WorldWideScience

Sample records for styphnate lead azide

  1. Photodissociation of aromatic azides

    Energy Technology Data Exchange (ETDEWEB)

    Budyka, M F [Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka, Moscow Region (Russian Federation)

    2008-08-31

    Quantitative data on the photochemical activity of aromatic azides and on the mechanism and kinetics of azido group photodissociation are analysed and described systematically for the first time. The results of quantum chemical calculations of the azide structure in the ground and lower electronically excited states and the potential energy surfaces along the reaction coordinate of the N-N{sub 2} bond dissociation are considered.

  2. Thermochemistry of organic azides revisited

    Energy Technology Data Exchange (ETDEWEB)

    Emel' yanenko, Vladimir N. [Department of Physical Chemistry, Kazan Federal University, Kremlevskaya str. 18, 420008 Kazan (Russian Federation); Algarra, Manuel [Centro de Investigação em Química, Departamento de Química, Faculdade de Ciências da Universidade do Porto, 4169-007 Porto (Portugal); Esteves da Silva, Joaquim C.G. [Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Málaga, 29071 Málaga (Spain); Hierrezuelo, Jesús [Department of Physical Chemistry, Kazan Federal University, Kremlevskaya str. 18, 420008 Kazan (Russian Federation); López-Romero, Juan M. [Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Málaga, 29071 Málaga (Spain); Verevkin, Sergey P., E-mail: sergey.verevkin@uni-rostock.de [Department of Physical Chemistry, Kazan Federal University, Kremlevskaya str. 18, 420008 Kazan (Russian Federation); Department of Physical Chemistry and Department “Science and Technology of Life, Light and Matter”, University of Rostock, Dr-Lorenz-Weg 1, D-18059, Rostock (Germany)

    2014-12-10

    Highlights: • Pure samples of 4-nitro-phenyl azide, 1-octyl- and 1-decyl-azides were prepared. • Vapour pressures, sublimation and vaporization enthalpies measured by transpiration. • Enthalpy of formation of 1-alkyl azides measured by combustion calorimetry. • Enthalpy of fusion of 4-nitro-phenyl azide measured by DSC. • Experimental gas enthalpies of formation were in agreement with calculated by G4. - Abstract: Highly pure samples of 4-nitro-phenyl azide, 1-octyl azide and 1 decyl-azide were prepared for thermochemical studies. Vapour pressures over the solid and the liquid sample of 4-nitro-phenyl azide have been determined by the transpiration method. The molar enthalpies of vaporization/sublimation for this compound were derived from the temperature dependencies of vapour pressures. The molar enthalpy of fusion of 4-nitro-phenyl azide was measured by DSC. The measured data set for 4-nitro-phenyl azide was successfully checked for internal consistency. Molar enthalpies of vaporization of 1-octyl azide and 1 decyl-azide were measured by transpiration. The molar enthalpies of formation of the liquid 1-octyl azide and 1 decyl-azides were derived from the combustion calorimetry. New experimental results for these organic azides have been used to derive their molar enthalpies of formation in the gas state and for comparison with results from quantum-chemical method G4.

  3. Thiophene-2-carbonyl azide

    Directory of Open Access Journals (Sweden)

    Michael Findlater

    2013-08-01

    Full Text Available The title compound, C5H3N3OS, is almost planar (r.m.s. deviation for the ten non-H atoms = 0.018 Å and forms an extended layer structure in the (100 plane, held together via hydrogen-bonding interactions between adjacent molecules. Of particular note is the occurrence of RC—H...N−=N+=NR interactions between an aromatic C—H group and an azide moiety which, in conjunction with a complementary C—H...O=C interaction, forms a nine-membered ring.

  4. Single-Step Azide Introduction in Proteins via an Aqueous Diazo Transfer

    NARCIS (Netherlands)

    van Dongen, Stijn; Teeuwen, R.L.M.; Nallani, Madhavan; van Berkel, S.S; Cornelissen, Jeroen Johannes Lambertus Maria; Nolte, Roeland; van Hest, Jan

    2009-01-01

    The controlled introduction of azides in proteins provides targetable handles for selective protein manipulation. We present here an efficient diazo transfer protocol that can be applied in an aqueous solution, leading to the facile introduction of azides in the side chains of lysine residues and at

  5. Life Cicle Inventory for Lead Azide Manufacture

    OpenAIRE

    Galante, E.B.F.; Haddad, A.; Boer, D.; Bonifácio,D.

    2014-01-01

    ABSTRACT: Like any other manufactured chemical compounds, explosives are produced using chemical reactants and other utilities (steam, heat, compressed air, feed water and electricity) and generate a set of environmental impacts (waste water, solid and water residue and waste heat, for example). On top of that, one can count the intrinsic hazard characteristic of explosives and the possibility of accidents involving these compounds. Within this framework, explosives present themselves as chem...

  6. Recent Advances in the Synthesis of High Explosive Materials

    Science.gov (United States)

    2016-05-09

    toxic mercury fulminate (1), adopted for use in some of the first percussion primer formulations in the early 1800s [6] and later by Alfred Nobel for...high sensitivity of mercury fulminate , and its ability to lose performance under high loading pressures paved the way for lead azide (2) to replace the... mercury fulminate (1), lead azide (2) and normal lead styphnate (3) and basic lead styphnate (4). 2.2. Why “Green” Primary Explosives? Over the past two

  7. DoD Contractors’ Safety Manual for Ammunition and Explosives

    Science.gov (United States)

    1986-03-01

    use as initiating elements in an explosive train. Examples are wet lead azide, wet lead styphnate, wet mercury fulminate , wet tetracene, and dry PETN...original shipping conLdiner or equivalent) L 1.3 Mercury Fulminate , wet A 1.I Nitrates (inorganic), except ammonium nitrate (in original shipping container...dry HMX, dry Lead azide, wet Lead styphnate, wet Mercury fulminate , wet PETN, dry Tetracene, wet GROUP B Cartridge cases, primed (w/o propellant

  8. DOD Ammunition and Explosives Safety Standards

    Science.gov (United States)

    2008-02-29

    following: bulk lead azide, lead styphnate, mercury fulminate , tetracene, dry cyclotrimethylenetrinitramine (RDX) (also known as cyclonite, hexogen, or...primary explosives are lead azide and mercury fulminate . AP1.191. Primary fragment. A fragment from material in intimate contact with reacting AE

  9. Towards the Synthesis of Graphene Azide from Graphene Oxide.

    Science.gov (United States)

    Halbig, Christian E; Rietsch, Philipp; Eigler, Siegfried

    2015-11-26

    In the last decades, organic azides haven proven to be very useful precursors in organic chemistry, for example in 1,3-dipolar cycloaddition reactions (click-chemistry). Likewise, azides can be introduced into graphene oxide with an almost intact carbon framework, namely oxo-functionalized graphene (oxo-G₁), which is a highly oxidized graphene derivative and a powerful precursor for graphene that is suitable for electronic devices. The synthesis of a graphene derivative with exclusively azide groups (graphene azide) is however still a challenge. In comparison also hydrogenated graphene, called graphene or halogenated graphene remain challenging to synthesize. A route to graphene azide would be the desoxygenation of azide functionalized oxo-G₁. Here we show how treatment of azide functionalized oxo-G₁ with HCl enlarges the π-system and removes strongly adsorbed water and some oxo-functional groups. This development reflects one step towards graphene azide.

  10. Metal azides under pressure: An emerging class of high energy ...

    Indian Academy of Sciences (India)

    ical properties.1 These materials belong to the category of primary explosives and can be used to detonate the secondary explosives.2 Among the inorganic metal azides, monovalent azides such as alkali metal azides are chemically and structurally simple compounds and have wide range of practical importance as ...

  11. Facile Quenching and Spatial Patterning of Cylooctynes via Strain-Promoted Alkyne-Azide Cycloaddition of Inorganic Azides.

    Science.gov (United States)

    Bjerknes, Matthew; Cheng, Hazel; McNitt, Christopher D; Popik, Vladimir V

    2017-05-17

    Little is known about the reactivity of strain-promoted alkyne-azide cycloaddition (SPAAC) reagents with inorganic azides. We explore the reactions of a variety of popular SPAAC reagents with sodium azide and hydrozoic acid. We find that the reactions proceed in water at rates comparable to those with organic azides, yielding in all cases a triazole adduct. The azide ion's utility as a cyclooctyne quenching reagent is demonstrated by using it to spatially pattern uniformly doped hydrogels. The facile quenching of cyclooctynes demonstrated here should be useful in other bioorthogonal ligation techniques in which cyclooctynes are employed, including SPANC, Diels-Alder, and thiol-yne.

  12. Medium Caliber Lead-Free Electric Primer. Version 2

    Science.gov (United States)

    2012-09-01

    conventional micron thermite powders resulting in significantly higher reaction rates. By 1998, LANL and the Naval Air Warfare Center Weapons...2 called MIC, Super- Thermite , Nano- Thermite and Nano-Structured Energetic Materials. An example of the reaction of an ENC is between aluminum...between 100 to 1000 times faster than traditional micron thermite composites and its energy content is superior to lead styphnate (-1.83 kJ/g and -4.49 kJ

  13. Metal azides under pressure: An emerging class of high energy ...

    Indian Academy of Sciences (India)

    Metal azides are well-known for their explosive properties such as detonation or deflagration. As chemically pure sources of nitrogen, alkali metal azides under high pressure have the ability to form polymeric nitrogen, an ultimate green high energy density material with energy density three times greater than that of known ...

  14. Selective Enrichment of Azide-Containing Peptides from Complex Mixtures

    NARCIS (Netherlands)

    Nessen, Merel A.; Kramer, Gertjan; Back, Jaapwillem; Baskin, Jeremy M.; Smeenk, Linde E. J.; de Koning, Leo J.; van Maarseveen, Jan H.; de Jong, Luitzen; Bertozzi, Carolyn R.; Hiemstra, Henk; de Koster, Chris G.

    2009-01-01

    A general method is described to sequester peptides containing azides from complex peptide mixtures, aimed at facilitating mass spectrometric analysis to study different aspects of proteome dynamics. The enrichment method is based on covalent capture of azide-containing peptides by the

  15. Proceedings of the Symposium on Lead and Copper Azides

    Science.gov (United States)

    1966-10-26

    placing an .lectronic relative humidity sensor inside a canister containing the polythene vessel and evacuating the air in the canister to 1/3 of...atmosphere. Signals from the R.H. sensor wc: e received externally. later permeated the polythene and, during the temperature fluctuations of the ISi’T(A...such as 1,2,3-benzo- triazole , and sacrificial methods employing zinc. In all cases where hydrazoic acid was converted into something less

  16. A Review of Safety Practices and Safety Training for the Explosives Field

    Science.gov (United States)

    1985-02-01

    burning, operators exposed to explosive fumes have a health hazard [e.g., lead from lead azide; mercury from mercury fulminate ; nitroglycerin (gela- 12 -~J...due to passage of electrical current, or by im- pact. Examples of primary explosives are: lead azide, mercury fulminate , and lead styphnate. Some of...protect personnel. Protective clothing is often required. Because of the toxic hazard from mercury vapor, a facility must be designed to take care of

  17. Reactivity studies of eta sup (6)-p-cymene ruthenium(II) carboxylato complexes towards azide some neutral ligands

    Digital Repository Service at National Institute of Oceanography (India)

    Singh, K.S.; Kollipara, M.R.

    azide in ethanol afforded a a dimeric compound [{(p- cymene)Ru(N 3 )Cl} 2 ] analogous to the complex obtained by the reaction of [{(η 6 -p-cymene)RuCl} 2 ] with trimethylsilyl azide by Bates et al. 16 (Scheme 2). The formation of this complex follows... of chlorine in the complexes 7 and 10 by other anions was achieved by treatment of the complexes with silver salts. Thus, reaction of complex 7 with silver acetate or trifluoro-silver acetate in ethanol leads to the displacement of chlorine with acetate...

  18. Vapor pressures and enthalpies of vaporization of azides

    Energy Technology Data Exchange (ETDEWEB)

    Verevkin, Sergey P., E-mail: sergey.verevkin@uni-rostock.de [Department of Physical Chemistry, University of Rostock, Dr-Lorenz-Weg 1, D-18059 Rostock (Germany); Emel' yanenko, Vladimir N. [Department of Physical Chemistry, University of Rostock, Dr-Lorenz-Weg 1, D-18059 Rostock (Germany); Algarra, Manuel [Centro de Geologia do Porto, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Manuel Lopez-Romero, J. [Department of Organic Chemistry, University of Malaga. Campus de Teatinos s/n, 29071 Malaga (Spain); Aguiar, Fabio; Enrique Rodriguez-Borges, J.; Esteves da Silva, Joaquim C.G. [Centro de Investigacao em Quimica (CIQ-UP), Faculdade de Ciencias da Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal)

    2011-11-15

    Highlights: > We prepared and measured vapor pressures and vaporization enthalpies of 7 azides. > We examined consistency of new and available in the literature data. > Data for geminal azides and azido-alkanes selected for thermochemical calculations. - Abstract: Vapor pressures of some azides have been determined by the transpiration method. The molar enthalpies of vaporization {Delta}{sub l}{sup g}H{sub m} of these compounds were derived from the temperature dependencies of vapor pressures. The measured data sets were successfully checked for internal consistency by comparison with vaporization enthalpies of similarly structured compounds.

  19. Lead

    Science.gov (United States)

    ... is serious about making sure companies that break the law are held accountable In the past year, EPA ... the health effects of lead in drinking water The law mandates no-lead products for drinking water after ...

  20. Lead

    Science.gov (United States)

    ... Test Safety Alert: Learn about CDC Recommendations Second Informational Call (CDC-RFA-17-1701PPHF17), April 5, 2017, ... CLPPP CAP Healthy Homes Assessment Tools Lead Health Literacy Initiative Refugee Tool Kit Resources Healthy Homes and ...

  1. Azide- and alkyne-derivatised α-amino acids

    DEFF Research Database (Denmark)

    Johansson, Karl Henrik; Pedersen, D.S.

    2012-01-01

    for their synthesis. In this review we have compiled available methods for synthesising optically active azide- and alkyne-derivatised α-amino acids that can be prepared from readily available α-amino acids. We highlight a number of commonly overlooked problems associated with existing methods and direct attention......With the emergence of the copper-catalysed Huisgen cycloaddition the use of azide- and alkyne-derivatised α-amino acids has found widespread use within most chemistry disciplines. Despite a growing interest in these building blocks researchers are struggling to identify the best way...... to unexplored possibilities. Azide- and alkyne-derivatised α-amino acids are finding widespread use within most chemistry disciplines. However, it is far from clear what the best way for the synthesis of these useful building blocks is. Herein we show the available methods for synthesis of optically active...

  2. Applications of Azide-Based Bioorthogonal Click Chemistry in Glycobiology

    Directory of Open Access Journals (Sweden)

    Xiu Zhang

    2013-06-01

    Full Text Available Click chemistry is a powerful chemical reaction with excellent bioorthogonality features: biocompatible, rapid and highly specific in biological environments. For glycobiology, bioorthogonal click chemistry has created a new method for glycan non-invasive imaging in living systems, selective metabolic engineering, and offered an elite chemical handle for biological manipulation and glycomics studies. Especially the [3 + 2] dipolar cycloadditions of azides with strained alkynes and the Staudinger ligation of azides and triarylphosphines have been widely used among the extant click reactions. This review focuses on the azide-based bioorthogonal click chemistry, describing the characteristics and development of these reactions, introducing some recent applications in glycobiology research, especially in glycan metabolic engineering, including glycan non-invasive imaging, glycomics studies and viral surface manipulation for drug discovery as well as other applications like activity-based protein profiling and carbohydrate microarrays.

  3. A practical one-pot synthesis of azides directly from alcohols

    Indian Academy of Sciences (India)

    Abstract. Alkyl/benzyl azides can be readily synthesized in excellent yields from their corresponding alcohols by stirring a solution of sodium azide in DMSO with a thoroughly ground equimolecular mixture of triphenylphosphine, iodine and imidazole.

  4. pH-dependent inhibition by azide and fluoride of the iron superoxide dismutase from Propionibacterium shermanii.

    Science.gov (United States)

    Meier, B; Scherk, C; Schmidt, M; Parak, F

    1998-04-15

    The iron-containing superoxide dismutase from Propionibacterium shermanii shows, in contrast with other iron superoxide dismutases, only a minor inhibition by azide or fluoride (10-100 mM) of up to 23% at pH 7.8. The activity of the protein with Mn bound to the active site was not diminished under the same conditions. The binding constant between azide and the Fe3+ ion was determined as approx. 2 mM and for fluoride approx. 2.3 mM; they are so far comparable to those known for other iron superoxide dismutases. This seems to be a discrepancy because all other iron superoxide dismutases so far known are described as being inhibited by 50-70% by 10 mM azide. However, towards lower pH there was a drastically increased inhibition by both anions. At pH 6.8 about 80% inhibition was exhibited by azide or fluoride at a concentration of 10 mM or higher. In contrast, on increasing the pH, azide or fluoride still bound to the Fe3+ at the active site but their inhibition capacity decreased. This observation implies that both anions bind to the metal at a position that is empty at low pH, whereas at higher pH water or a negatively charged hydroxyl anion is bound. It is likely that the superoxide anion binds to the same position and has to replace the sixth ligand, leading to a diminished catalytic activity of the superoxide dismutase owing to steric and/or electrostatic inhibition of the ligand.

  5. Morphogical effects of sodium azide on tomato ( Lycopersicon ...

    African Journals Online (AJOL)

    Dry seeds of tomato (Lycopersicon esculentun Mill), varieties T106, T244 and T420 obtained from the Institute of Agriculture Research, Ahmadu Bello University Zaria, Nigeria were treated with sodium azide at concentrations of 1.0, 2.0 and 4.0 mM aimed at determining the effects of the mutagen on the morphological ...

  6. The effects of sodium azide and colchicine treatments on ...

    African Journals Online (AJOL)

    GREGO

    2007-03-05

    Mar 5, 2007 ... The frequency of mutation/injury increased with increasing concentrations of the mutagens. The LC50 values based on survival percentages in the M1 generation were fixed at 0.0776 and 0.0473% for sodium azide and colchicine respectively. There were dose related effects of the mutagenic treatments on ...

  7. 40 CFR 721.983 - Sulfonyl azide intermediate (generic).

    Science.gov (United States)

    2010-07-01

    ...). 721.983 Section 721.983 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC... subject to reporting. (1) The chemical substance identified generically as sulfonyl azide intermediate... subpart A of this part apply to this section except as modified by this paragraph. (1) Recordkeeping...

  8. Electron Transfer from Azide Radical to Histidine Generates ...

    African Journals Online (AJOL)

    The formation of histidinyl radical (HR), which is a product of electron transfer reaction between histidine and some free radicals, was studied by pulse radiolysis. The reaction between histidine and azide radicals was found to produce HR, which has a distinct absorption spectrum with peaks at 300, 480 and 520 nm.

  9. Effects of sodium azide on yield parameters of groundnut (Arachis ...

    African Journals Online (AJOL)

    GREGO

    2007-03-19

    Mar 19, 2007 ... J. K. Mensah*, and B. Obadoni. Department of Botany Ambrose Alli University, Ekpoma, Nigeria. Accepted 22 January, 2007. The mutagenic effects of different concentrations of sodium azide (0.01 – 0.05%) on groundnut (Arachis hypogaea L. cv SS1145B and RMP 91) were investigated. The characters ...

  10. Thermal Decompositon Studies Of Pre-Irradiated Nickel (II) Azides ...

    African Journals Online (AJOL)

    The effect of pre-irradiation on the thermal decomposition of three samples of nickel (II) azide was studied. It was found that the rates of thermal decomposition of Ni(OH)N3 increased substantially with increase in pre-irradiation dosage. The initial reaction rates change from time-dependant nucleation law for the unirradiated ...

  11. Cyanogen Azide. Ionization Potentials and Ab Initio SCF MO Calculation

    DEFF Research Database (Denmark)

    Bak, Börge; Jansen, Peter; Stafast, Herbert

    1975-01-01

    The Ne(I) and He(I) photoelectron(PE) spectra of cyanogen azide, NCN3, have been recorded at high resolution. Their interpretation is achieved by comparison with the PE spectrum of HN3 and an ab initio LCGO SCF MO calculation. Deviations from Koopmans' theorem of quite different magnitudes...

  12. Copper-catalyzed azide alkyne cycloaddition polymer networks

    Science.gov (United States)

    Alzahrani, Abeer Ahmed

    -CuAAC reaction and a chain-growth acrylate homopolymerization were demonstrated and used to form branched polymer structures. A bulk, organic soluble initiation system consisting of a Cu(II) salt and a primary amine was also examined in both model reactions and in bulk polymerizations. The system was shown to be highly efficient, leading to nearly complete CuAAC polymerization at ambient temperature. Increasing the ratio of amine to copper from 1 to 4 increases the CuAAC reaction rate significantly from 4 mM/min for 1:1 ratio of Cu(II):hexyalmine to 14mM/min for 1:4 ratio. The concentration dependence of the amine on the reaction rate enables the polymerization rate to be controlled simply by manipulating the hexylamine concentration. Sequential thiol--acrylate and photo-CuAAC click reactions were utilized to form two-stage reactive polymer networks capable of generating wrinkles in a facile manner. The click thiol-Michael addition reaction was utilized to form a cross-linked polymer with residual, reactive alkyne sites that remained tethered throughout the network. The latent, unreacted alkyne sites are subsequently reacted with diazide monomers via a photoinduced Cu(I)-catalyzed alkyne-azide cycloaddition (CuAAC) reaction to increase the cross-link density. Increased cross-linking raised the modulus and glass transition temperature from 1.6 MPa and 2 °C after the thiol-acrylate reaction to 4.4 MPa and 22 °C after the CuAAC reaction, respectively. The double click reaction approach led to micro-wrinkles with well-controlled wavelength and amplitude of 8.50 +/- 1.6 and 1.4 μm, respectively, for a polymer with a 1280 μm total film thickness. Additionally, this approach further enables spatial selectivity of wrinkle formation by photo-patterning. The CuAAC-based polymerization was also used to design smart, responsive porous materials from well-defined CuAAC networks, which possesses a high glass transition temperature (Tg= 115°C) due to the formation of the triazole linkages

  13. Techniques in gas-phase thermolyses - Part 7. Direct surface participation in gas-phase Curie-point pyrolysis: The pyrolysis of phenyl azide

    DEFF Research Database (Denmark)

    Egsgaard, Helge; Carlsen, Lars

    1986-01-01

    The possible direct participation of the hot reactor surface in the formation of pyrolysis products was elucidated through the pyrolytic decomposition of phenyl azide. It is demonstrated that the intermediate phenyl nitrene generated reacts with elemental carbon at the filament surface, leading...

  14. Photolysis of nickel hydroxy azide. | IROM | Global Journal of Pure ...

    African Journals Online (AJOL)

    This is evident in the linear dependence of the rate of photolysis on the intensity. The rate of photolysis of Ni(OH)N3 is observed to be lower than that of Ni(N3)2 by about a factor of 10. Global Journal of Pure and Applied Sciences Volume , No 1 January (2001) pp. 73-80. KEY WORDS: Photolysis, Azide, Quantum Yield, ...

  15. Imaging bacterial peptidoglycan with near-infrared fluorogenic azide probes

    Science.gov (United States)

    Shieh, Peyton; Siegrist, M. Sloan; Cullen, Andrew J.; Bertozzi, Carolyn R.

    2014-01-01

    Fluorescent probes designed for activation by bioorthogonal chemistry have enabled the visualization of biomolecules in living systems. Such activatable probes with near-infrared (NIR) emission would be ideal for in vivo imaging but have proven difficult to engineer. We present the development of NIR fluorogenic azide probes based on the Si-rhodamine scaffold that undergo a fluorescence enhancement of up to 48-fold upon reaction with terminal or strained alkynes. We used the probes for mammalian cell surface imaging and, in conjunction with a new class of cyclooctyne d-amino acids, for visualization of bacterial peptidoglycan without the need to wash away unreacted probe. PMID:24706769

  16. Mutagenic Effects of Sodium Azide on Capsicum anuum L.

    OpenAIRE

    Cecilie Longid

    1992-01-01

    Dry seeds from pure lines of three varieties of pepper (Capsicum anuum L.) were treated for 2 hours at 30ÉC with solutions of 0.12, 0.25, 0.50 and O.75 mM sodium azide in phosphate buffer at pH 3. Data in the M1 show a decrease in germination percentage, height at different stages of growth, number of leaves and seed set. Germination percentage and seed set were reduced significantly. Chlorophyll-deficient seedlings were observed in the M2. The most frequent chlorophyll mutations were the vir...

  17. Evolving Structural Diversity and Metallicity in Compressed Lithium Azide

    KAUST Repository

    Prasad, Dasari L. V. K.

    2013-10-10

    In pursuit of new stable nitrogen-rich phases and of a possible insulator-metal transition, the ground-state electronic structure of lithium azide, LiN3, is investigated from 1 atm to 300 GPa (∼2-fold compression) using evolutionary crystal structure exploration methods coupled with density functional theoretical calculations. Two new LiN3 phases, containing slightly reduced and well-separated N2 units, are found to be enthalpically competitive with the known lithium azide crystal structure at 1 atm. At pressures above 36 GPa nitrogen-rich assemblies begin to evolve. These incorporate NN bond formation beyond that in N2 or N3 -. N6 rings and infinite one-dimensional linear nitrogen chains (structural analogues to polyacetylene) appear. Above 200 GPa quasi-one- and two-dimensional extended puckered hexagonal and decagonal nitrogen layers emerge. The high-pressure phase featuring linear chains may be quenchable to P = 1 atm. With increasing pressure the progression in electrical conductivity is from insulator to metal. © 2013 American Chemical Society.

  18. A Pressure Bar Test Free of Asbestos for Determination of Detonator Performance

    Science.gov (United States)

    1988-10-01

    used in Initiating Devices Cal/g kJ/g A. SINGLE COMPOUNDS: Lead 2,4-Dinitroresorcinate (RD 1337) 270 1.13 Lead Azide (Service) 385 1.61 Mercury ... Fulminate 420 1.76 Lead Styphnate (Normal) 450 1.88 CE, density 1.35 to 1.41 Mg/m 3 910 3.81 CE, density 1.65 Mg/m 1020 4.27 CE, max. pressing density 1110

  19. Collagen labelling with an azide-proline chemical reporter in live cells.

    Science.gov (United States)

    Amgarten, Beatrice; Rajan, Rakesh; Martínez-Sáez, Nuria; Oliveira, Bruno L; Albuquerque, Inês S; Brooks, Roger A; Reid, David G; Duer, Melinda J; Bernardes, Gonçalo J L

    2015-03-28

    We have developed a strategy for selective imaging of collagen in live foetal ovine osteoblasts. Our approach involves the incorporation of an azide-tagged proline in the biosynthesis of collagen followed by labelling using a strain-promoted [3+2] azide-alkyne cycloaddition reaction.

  20. Azide binding to the trinuclear copper center in laccase and ascorbate oxidase

    DEFF Research Database (Denmark)

    Gromov, I; Marchesini, A; Farver, O

    1999-01-01

    Azide binding to the blue copper oxidases laccase and ascorbate oxidase (AO) was investigated by electron paramagnetic resonance (EPR) and pulsed electron-nuclear double resonance (ENDOR) spectroscopies. As the laccase : azide molar ratio decreases from 1:1 to 1:7, the intensity of the type 2 (T2...... characteristics was found in the AO : azide (1:7) sample. The g binding disrupts the anti-ferromagnetic coupling of the type 3 (T3) Cu(II) pair. Analysis of the position of the g ... of the protein molecules, and in the remaining part a different azide binding mode is observed. The 130 K EPR spectra of AO and laccase with azide (1:7) exhibit, in addition to an unperturbed T2 Cu(II) signal, new features in the g parallel region that are attributed to a perturbed T2 in protein molecules where...

  1. Mutagenic Effects of Sodium Azide on Capsicum anuum L.

    Directory of Open Access Journals (Sweden)

    Cecilie Longid

    1992-06-01

    Full Text Available Dry seeds from pure lines of three varieties of pepper (Capsicum anuum L. were treated for 2 hours at 30ÉC with solutions of 0.12, 0.25, 0.50 and O.75 mM sodium azide in phosphate buffer at pH 3. Data in the M1 show a decrease in germination percentage, height at different stages of growth, number of leaves and seed set. Germination percentage and seed set were reduced significantly. Chlorophyll-deficient seedlings were observed in the M2. The most frequent chlorophyll mutations were the viridis type followed by chlorina, xantha and albina. Very few xantha and albina mutants were observed.

  2. Evidence that azide occupies the chloride binding site near the manganese cluster in photosystem II.

    Science.gov (United States)

    Yu, Hui; Aznar, Constantino P; Xu, Xianzhong; Britt, R David

    2005-09-13

    The effect of adding azide to photosystem II (PS II) membrane samples (BBY preparation), with or without chloride, has been investigated using continuous wave (CW) and pulsed EPR spectroscopy. In the BBY samples with 25 mM chloride, we observed that the inhibition induced by azide is partly recovered by the addition of bicarbonate. Electron spin-echo envelope modulation (ESEEM) was used to search for spin transitions of 15N nuclei magnetically coupled to the S2 state Mn cluster (multiline EPR signal form) in 15N (single terminal label) azide-treated samples with negative results. However, an 15N ESEEM peak was observed in parallel chloride-depleted PS II samples when the 15N-labeled azide is added. However, this peak is absent in chloride-depleted samples incubated in buffer containing both chloride and [15N]azide. Thus these results demonstrate an azide binding site in the immediate vicinity of the Mn cluster, and since this site appears to be competitive with chloride, these results provide further evidence that chloride is bound proximal to the Mn cluster as well. Discussion on the possible interplay between azide, chloride, and bicarbonate is provided.

  3. Azide resistance in Rhizobium ciceri linked with superior symbiotic nitrogen fixation.

    Science.gov (United States)

    Bhaskar, V Vijay

    2004-12-01

    Isolated azide resistant (AzR) native R. ciceri strain 18-7 was resistant to sodium azide at 10 microg/ml. To find if nif-reiteration is responsible for azide resistance and linked to superior symbiotic nitrogen fixation, transposon (Tn5) induced azide sensitive mutants were generated. Using 4 kb nif-reiterated Sinorhizobium meliloti DNA, a clone C4 that complemented azide sensitivity was isolated by DNA hybridization from genomic library of chickpea Rhizobium strain Rcd301. EcoRI restriction mapping revealed the presence of 7 recognition sites with a total insert size of 19.17 kb. Restriction analysis of C4 clone and nif-reiterated DNA (pRK 290.7) with EcoRI and XhoI revealed similar banding pattern. Wild type strain 18-7, mutant M126 and complemented mutant M126(C4) were characterized for symbiotic properties (viz., acetylene reduction assay, total nitrogen content, nodule number and fresh and dry weight of the infected plants) and explanta nitrogenase activity. Our results suggested that azide resistance, nif-reiteration, and superior symbiotic effectiveness were interlinked with no correlation between ex-planta nitrogenase activity and azide resistance in R. ciceri.

  4. Stereoselective Dynamic Cyclization of Allylic Azides: Synthesis of Tetralins, Chromanes, and Tetrahydroquinolines.

    Science.gov (United States)

    Porter, Matthew R; Shaker, Rami M; Calcanas, Cristian; Topczewski, Joseph J

    2018-01-10

    This report describes the stereoselective synthesis of 3-azido-tetralins, -chromanes, and -tetrahydroquinolines via a tandem allylic azide rearrangement/Friedel-Crafts alkylation. Exposure of allylic azides with a pendant trichloroacetimidate to catalytic quantities of AgSbF6 proved optimal for this transformation. This cascade successfully differentiates the equilibrating azide isomers, providing products in excellent yield and selectivity (>25 examples, up to 94% yield and >25:1 dr). In many cases, the reactive isomer is only a trace fraction of the equilibrium mixture, keenly illustrating the dynamic nature of these systems. We demonstrate the utility of this process via a synthesis of hasubanan.

  5. Effects of sodium azide on the abundance of prokaryotes and viruses in marine samples.

    Directory of Open Access Journals (Sweden)

    Christian Winter

    Full Text Available Flow cytometry is set to become the standard method for enumerating prokaryotes and viruses in marine samples. However, the samples need to be flash-frozen in liquid nitrogen directly after aldehyde fixation. Because liquid nitrogen may not always be available, we tested the potential of sodium azide as a preservative for prokaryotes and viruses in marine samples as a possible alternative. For that we conducted incubation experiments with untreated and sodium azide treated marine water samples at 4°C and room temperature. The data indicate that sodium azide cannot be used to maintain marine samples used for the enumeration of prokaryotes and viruses.

  6. Electronic Structure of the Azide Group in 3¢-Azido-3¢-deoxythymidine (AZT Compared to Small Azide Compounds

    Directory of Open Access Journals (Sweden)

    Feng Wang

    2009-07-01

    Full Text Available Theoretical calculations for some structural and electronic properties of the azide moiety in the nucleoside reverse transcriptase (RT inhibitor 3¢-azido-3¢-deoxythymidine (AZT are reported. These properties, which include geometrical properties in three dimensional space, Hirshfeld charges, electrostatic potential (MEP, vibrational frequencies, and core and valence ionization spectra, are employed to study how the azide group is affected by the presence of a larger fragment. For this purpose, two small but important organic azides, hydrazoic acid and methyl azide, are also considered. The general features of trans Cs configuration for RNNN fragments[1] is distorted in the large AZT bio-molecule. Hirshfeld charge analysis shows charges are reallocated more evenly on azide when the donor group R is not a single atom. Infrared and photoelectron spectra reveal different aspects of the compounds. In conclusion, the electronic structural properties of the compounds depend on the specific property, the local structure and chemical environment of a species.

  7. Cyanide vs. azide "magnetic arm wrestling": Mn(II)-Nb(IV) and Mn(II)-Mo(IV) magnetic coordination polymers with mixed bridging.

    Science.gov (United States)

    Handzlik, Gabriela; Kozieł, Marcin; Olejniczak, Anna; Sieklucka, Barbara; Pinkowicz, Dawid

    2017-08-29

    Two magnetic coordination polymers with mixed cyanide-azide bridging based on octacyanoniobate(iv) and octacyanomolybdate(iv) are reported: {(NH4)[(H2O)Mn(II)-(μ-N3)-Mn(II)(H2O)][M(IV)(CN)8]·3H2O}n Mn2MN3 (M = Nb or Mo). Cyanide ligands form the 3-D framework of Mn2MN3, while azide ligands connect two Mn(II) centres together. Both CN(-) and N3(-) are known in magnetochemistry for their marked magnetic coupling abilities which in the case of Mn2NbN3 lead to competitive antiferromagnetic interactions within the Nb(IV)-CN-Mn(II) and Mn(II)-N3-Mn(II) structural motifs. This competition results in a peculiar magnetic behaviour consistent with a non-collinear magnetic structure.

  8. Synergistic cytotoxic effect of tetrachlorocatechol and sodium azide in Escherichia coli: toxicity, metabolism, and mechanistic aspects.

    Science.gov (United States)

    Levy, Smadar; Chevion, Mordechai

    2009-07-01

    Pentachlorophenol (PCP) is used in industrial and domestic applications, including as a biocide and a wood preservative. Metabolism of PCP undergoes oxidative dechlorination, forming tetrachlorocatechol (TCC) and tetrachlorohydroquinone (TCHQ). Both sodium azide (NaN(3)) and TCC appear naturally in soil. None of them are cytotoxic by themselves or facilitate autooxidation. Here, we show that their combination leads to synergistic cytotoxicity (>6 log bacterial killing) to Escherichia coli. The rate of oxygen consumption in a cell-free system showed that NaN(3) increases TCC oxidation by 520-fold. The synergism coefficient to cells was calculated as 96 or greater, and we have shown the formation of a new compound. It is suggested that the intermediate species, o-tetrachlorosemiquinine, and an unknown, nitrogen-centered free radical, both visualized by electron-spin resonance, are harmful species responsible for the synergistic cytotoxicity of TCC/NaN(3), rather than the endproduct formed during the reaction. Desferrioxamine and 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide offered nearly complete protection, but through radical scavenging rather than through chelating properties. The mechanism of damage for TCC compared to its analogue, TCHQ, were investigated, and whereas the cellular damage of TCHQ/NaN(3) is through a site-specific mechanism, in the case of TCC/NaN(3) it is through the accumulation of the component(s) in the bacterial cell membrane, eventually leading to dysfunction, as evidenced by electron microscopy.

  9. Feasibility of Obtaining Hypervelocity Acceleration Using Propellant Lined Launch Tubes

    Science.gov (United States)

    1970-10-01

    the same way.10 For example, mercury fulminate ignited by a hot wire may burn with an initial speed as low as 5 cm. sec. Lead styphnate and the organic...on the Velocity of Detonation of Tetryl; Density O.9g.c ......... 22 2 Detonation Velocities in Thin Films of Some Inorganic Azides and Fulminates ...mm of mercury ) and then the pressure of the surroundings of the strand was lowered to the desired level. Burn rates were measured using high speed

  10. Alkylating efficiency of sodium azide on pod yield, nut size and ...

    African Journals Online (AJOL)

    Alkylating efficiency of sodium azide on pod yield, nut size and nutrition composition of Samnut 10 and Samnut 20 varieties of groundnut (Arachis hypogea L.) D A Animasaun, S Oyedeji, M A Azeez, A O Onasanya ...

  11. Accelerating Strain-Promoted Azide-Alkyne Cycloaddition Using Micellar Catalysis.

    Science.gov (United States)

    Anderton, Grant I; Bangerter, Alyssa S; Davis, Tyson C; Feng, Zhiyuan; Furtak, Aric J; Larsen, Jared O; Scroggin, Triniti L; Heemstra, Jennifer M

    2015-08-19

    Bioorthogonal conjugation reactions such as strain-promoted azide-alkyne cycloaddition (SPAAC) have become increasingly popular in recent years, as they enable site-specific labeling of complex biomolecules. However, despite a number of improvements to cyclooctyne design, reaction rates for SPAAC remain significantly lower than those of the related copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. Here we explore micellar catalysis as a means to increase reaction rate between a cyclooctyne and hydrophobic azide. We find that anionic and cationic surfactants provide the most efficient catalysis, with rate enhancements of up to 179-fold for reaction of benzyl azide with DIBAC cyclooctyne. Additionally, we find that the presence of surfactant can provide up to 51-fold selectivity for reaction with a hydrophobic over hydrophilic azide. A more modest, but still substantial, 11-fold rate enhancement is observed for micellar catalysis of the reaction between benzyl azide and a DIBAC-functionalized DNA sequence, demonstrating that micellar catalysis can be successfully applied to hydrophilic biomolecules. Together, these results demonstrate that micellar catalysis can provide higher conjugation yields in reduced time when using hydrophobic SPAAC reagents.

  12. Structural Determinants of Alkyne Reactivity in Copper-Catalyzed Azide-Alkyne Cycloadditions

    Directory of Open Access Journals (Sweden)

    Xiaoguang Zhang

    2016-12-01

    Full Text Available This work represents our initial effort in identifying azide/alkyne pairs for optimal reactivity in copper-catalyzed azide-alkyne cycloaddition (CuAAC reactions. In previous works, we have identified chelating azides, in particular 2-picolyl azide, as “privileged” azide substrates with high CuAAC reactivity. In the current work, two types of alkynes are shown to undergo rapid CuAAC reactions under both copper(II- (via an induction period and copper(I-catalyzed conditions. The first type of the alkynes bears relatively acidic ethynyl C-H bonds, while the second type contains an N-(triazolylmethylpropargylic moiety that produces a self-accelerating effect. The rankings of reactivity under both copper(II- and copper(I-catalyzed conditions are provided. The observations on how other reaction parameters such as accelerating ligand, reducing agent, or identity of azide alter the relative reactivity of alkynes are described and, to the best of our ability, explained.

  13. Structure of a Switchable Subtilisin Complexed with a Substrate and with the Activator Azide

    Energy Technology Data Exchange (ETDEWEB)

    Gallagher, Travis; Ruan, Biao; London, Mariya; Bryan, Molly A.; Bryan, Philip N.; NIST

    2010-01-12

    An engineered variant of the protease subtilisin from Bacillus amyloliquefaciens, in which the D32A mutation renders the enzyme's activity dependent on the presence of certain small anions such as fluoride or azide, has been produced. This modified enzyme has applications as an azide or fluoride-triggered expression-purification tool. We report activity measurements showing that the enzyme is activated more than 3000-fold by azide and describe the 1.8 {angstrom} resolution structure of an inactive form (by replacing the catalytic nucleophile Ser 221 with alanine) of the protease, in complex with azide and with a substrate that spans the active site. Both enzyme and substrate have been engineered to increase their stability and the affinity of their interaction. The substrate is based on a stabilized subtilisin prodomain, extended across the active site by the addition of four residues at its C-terminus. In the crystal structure, the substrate is well-ordered across the active site, and the azide anion is observed bound adjacent to Ala 32. The structures of the substrate complex in three different crystals (anion-free, fluoride-soaked, and azide-soaked) are compared. These structures provide extensive information for understanding subtilisin's substrate binding and catalytic mechanism, and for the development of biotechnology tools based on anion-activated proteolysis. The mechanism of anion-dependent proteolysis appears to be a slight modification of the accepted charge-relay mechanism for serine proteases.

  14. Metal-catalysed azidation of tertiary C-H bonds suitable for late-stage functionalization

    Science.gov (United States)

    Sharma, Ankit; Hartwig, John F.

    2015-01-01

    Many enzymes oxidize unactivated aliphatic C-H bonds selectively to form alcohols; however, biological systems do not possess enzymes that catalyse the analogous aminations of C-H bonds. The absence of such enzymes limits the discovery of potential medicinal candidates because nitrogen-containing groups are crucial to the biological activity of therapeutic agents and clinically useful natural products. In one prominent example illustrating the importance of incorporating nitrogen-based functionality, the conversion of the ketone of erythromycin to the -N(Me)CH2- group in azithromycin leads to a compound that can be dosed once daily with a shorter treatment time. For such reasons, synthetic chemists have sought catalysts that directly convert C-H bonds to C-N bonds. Most currently used catalysts for C-H bond amination are ill suited to the intermolecular functionalization of complex molecules because they require excess substrate or directing groups, harsh reaction conditions, weak or acidic C-H bonds, or reagents containing specialized groups on the nitrogen atom. Among C-H bond amination reactions, those forming a C-N bond at a tertiary alkyl group would be particularly valuable, because this linkage is difficult to form from ketones or alcohols that might be created in a biosynthetic pathway by oxidation. Here we report a mild, selective, iron-catalysed azidation of tertiary C-H bonds that occurs without excess of the valuable substrate. The reaction tolerates aqueous environments and is suitable for the functionalization of complex structures in the late stages of a multistep synthesis. Moreover, this azidation makes it possible to install a range of nitrogen-based functional groups, including those from Huisgen `click' cycloadditions and the Staudinger ligation. We anticipate that these reactions will create opportunities to modify natural products, their precursors and their derivatives to produce analogues that contain different polarity and charge as a

  15. EPR and ENDOR spectroscopic study of the reactions of aromatic azides with gallium trichloride.

    Science.gov (United States)

    Bencivenni, Giorgio; Cesari, Riccardo; Nanni, Daniele; El Mkami, Hassane; Walton, John C

    2010-11-21

    The reactions of gallium trichloride with phenyl and deuterio-phenyl azides, as well as with 4-methoxyphenyl azide and deuterium isotopomers, were examined by product analysis, CW EPR spectroscopy and pulsed ENDOR spectroscopy. The products included the corresponding anilines together with 4-aminodiphenylamine type dimers, and polyanilines. Complex CW EPR spectra of the radical cations of the dimers [ArNHC(6)H(4)NH(2)](+)˙ and trimers [ArNHC(6)H(4)NHC(6)H(4)NH(2)](+)˙ were obtained. These EPR spectra were analysed with the help of data from the deuterium-substituted analogues as well as the pulse Davies ENDOR spectra. DFT computations of the radical cations provided corroborating evidence and suggested the unpaired electrons were accommodated in extensive π-delocalised orbitals. A mechanism to account for the reductive conversion of aromatic azides to the corresponding anilines and thence to the dimers and trimers is proposed.

  16. Imaging Newly Transcribed RNA in Cells by Using a Clickable Azide-Modified UTP Analog.

    Science.gov (United States)

    Sawant, Anupam A; Galande, Sanjeev; Srivatsan, Seergazhi G

    2018-01-01

    Robust RNA labeling and imaging methods that enable the understanding of cellular RNA biogenesis and function are highly desired. In this context, we describe a practical chemical labeling method based on a bioorthogonal reaction, namely, azide-alkyne cycloaddition reaction, which facilitates the fluorescence imaging of newly transcribed RNA in both fixed and live cells. This strategy involves the transfection of an azide-modified UTP analog (AMUTP) into mammalian cells, which gets specifically incorporated into RNA transcripts by RNA polymerases present inside the cells. Subsequent posttranscriptional click reaction between azide-labeled RNA transcripts and a fluorescent alkyne substrate enables the imaging of newly synthesized RNA in cells by confocal microscopy. Typically, 50 μM to 1 mM of AMUTP and a transfection time of 15-60 min produce significant fluorescence signal from labeled RNA transcripts in cells.

  17. Functionalization of Graphene Nanoplatelets Using Sugar Azide for Graphene/Epoxy Nanocomposites

    Science.gov (United States)

    2014-06-20

    was supplied by XG Sciences, USA. 2,3,4-Tri-O-acetyl-β-D-xylopyranosyl azide, known as Sugar azide (SA) was purchased from Sigma Aldrich. Epoxy ( Epon ... 828 ) was purchased from Miller Stephenson. Ethyl acetate (EtOAc), sodium methoxide (NaOMe) and Metaphenylene Diamine (MPDA) were purchased from...Neat Epon 355 394 153.7 1.09 Epon /GnP (2%) 339 384 144.8 0.95 Epon /SAMG (2%) 363 408 163.6 1.03

  18. clickECM: Development of a cell-derived extracellular matrix with azide functionalities.

    Science.gov (United States)

    Ruff, S M; Keller, S; Wieland, D E; Wittmann, V; Tovar, G E M; Bach, M; Kluger, P J

    2017-04-01

    In vitro cultured cells produce a complex extracellular matrix (ECM) that remains intact after decellularization. The biological complexity derived from the variety of distinct ECM molecules makes these matrices ideal candidates for biomaterials. Biomaterials with the ability to guide cell function are a topic of high interest in biomaterial development. However, these matrices lack specific addressable functional groups, which are often required for their use as a biomaterial. Due to the biological complexity of the cell-derived ECM, it is a challenge to incorporate such functional groups without affecting the integrity of the biomolecules within the ECM. The azide-alkyne cycloaddition (click reaction, Huisgen-reaction) is an efficient and specific ligation reaction that is known to be biocompatible when strained alkynes are used to avoid the use of copper (I) as a catalyst. In our work, the ubiquitous modification of a fibroblast cell-derived ECM with azides was achieved through metabolic oligosaccharide engineering by adding the azide-modified monosaccharide Ac4GalNAz (1,3,4,6-tetra-O-acetyl-N-azidoacetylgalactosamine) to the cell culture medium. The resulting azide-modified network remained intact after removing the cells by lysis and the molecular structure of the ECM proteins was unimpaired after a gentle homogenization process. The biological composition was characterized in order to show that the functionalization does not impair the complexity and integrity of the ECM. The azides within this "clickECM" could be accessed by small molecules (such as an alkyne-modified fluorophore) or by surface-bound cyclooctynes to achieve a covalent coating with clickECM. The clickECM was produced by the incorporation of azide-functionalized sugar analogues into the extracellular glycans of fibroblast cell cultures by metabolic oligosaccharide engineering. By introducing these azide groups into the glycan structures, we enabled this cell-derived ECM for bioorthogonal click

  19. Protein enrichment by capture-release based on strain-promoted cycloaddition of azide with bicyclononyne (BCN).

    NARCIS (Netherlands)

    Temming, R.P.; Scherpenzeel, M. van; Brinke, E. te; Schoffelen, S.; Gloerich, J.; Lefeber, D.J.; Delft, F.L. van

    2012-01-01

    An enrichment strategy was devised for azide derivatized macromolecules, based on strain-promoted alkyne-azide cycloaddition (SPAAC) and a cleavable linker. A ring-strained alkyne, bicyclo[6.1.0]non-4-yne (BCN), was covalently attached to agarose beads via a hydrazine-sensitive linker. Benchmark

  20. Site-specific bioconjugation of a murine dihydrofolate reductase enzyme by copper(I-catalyzed azide-alkyne cycloaddition with retained activity.

    Directory of Open Access Journals (Sweden)

    Sung In Lim

    Full Text Available Cu(I-catalyzed azide-alkyne cycloaddition (CuAAC is an efficient reaction linking an azido and an alkynyl group in the presence of copper catalyst. Incorporation of a non-natural amino acid (NAA containing either an azido or an alkynyl group into a protein allows site-specific bioconjugation in mild conditions via CuAAC. Despite its great potential, bioconjugation of an enzyme has been hampered by several issues including low yield, poor solubility of a ligand, and protein structural/functional perturbation by CuAAC components. In the present study, we incorporated an alkyne-bearing NAA into an enzyme, murine dihydrofolate reductase (mDHFR, in high cell density cultivation of Escherichia coli, and performed CuAAC conjugation with fluorescent azide dyes to evaluate enzyme compatibility of various CuAAC conditions comprising combination of commercially available Cu(I-chelating ligands and reductants. The condensed culture improves the protein yield 19-fold based on the same amount of non-natural amino acid, and the enzyme incubation under the optimized reaction condition did not lead to any activity loss but allowed a fast and high-yield bioconjugation. Using the established conditions, a biotin-azide spacer was efficiently conjugated to mDHFR with retained activity leading to the site-specific immobilization of the biotin-conjugated mDHFR on a streptavidin-coated plate. These results demonstrate that the combination of reactive non-natural amino acid incorporation and the optimized CuAAC can be used to bioconjugate enzymes with retained enzymatic activity.

  1. Catalytic Intermolecular Cross-Couplings of Azides and LUMO-Activated Unsaturated Acyl Azoliums

    KAUST Repository

    Li, Wenjun

    2017-02-15

    An example for the catalytic synthesis of densely functionalized 1,2,3-triazoles through a LUMO activation mode has been developed. The protocol is enabled by intermolecular cross coupling reactions of azides with in situ-generated alpha,beta-unsaturated acyl azoliums. High yields and broad scope as well as the investigation of reaction mechanism are reported.

  2. Regioselectivity Control of the Ring Opening of Epoxides With Sodium Azide in a Microreactor

    NARCIS (Netherlands)

    Munirathinam, Rajesh; Joe, D.J.; Huskens, Jurriaan; Verboom, Willem

    2012-01-01

    The reaction of different types of aromatic and aliphatic epoxides with sodium azide to give vicinal azido alcohols was studied in a microreactor with and without pillars in the channels. Dependent on the substrate, the regioselectivity of the ring opening is affected by the used solvent system,

  3. 49 CFR 173.182 - Barium azide-50 percent or more water wet.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Barium azide-50 percent or more water wet. 173.182 Section 173.182 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS... Class 1 and Class 7 § 173.182 Barium azide—50 percent or more water wet. Barium azide—50 percent or more...

  4. In situ generation of the Ohira-Bestmann Reagent from stable sulfonyl azide

    DEFF Research Database (Denmark)

    Jepsen, Tue Heesgaard; Kristensen, Jesper Langgaard

    2014-01-01

    We report an improved method for in situ generation of the Ohira-Bestmann reagent. Using the recently reported bench stable imidazole-1-sulfonyl azide as diazotransfer reagent, this new method represents a safe and scalable approach for the transformation of aldehydes into terminal alkynes...

  5. Azidoperfluoroalkanes: Synthesis and Application in Copper(I)-Catalyzed Azide-Alkyne Cycloaddition

    Czech Academy of Sciences Publication Activity Database

    Blastik, Zsófia E.; Voltrová, Svatava; Matoušek, V.; Jurásek, Bronislav; Manley, David W.; Klepetářová, Blanka; Beier, Petr

    2017-01-01

    Roč. 56, č. 1 (2017), s. 346-349 ISSN 1433-7851 EU Projects: European Commission(XE) 607787 - FLUOR21 Institutional support: RVO:61388963 Keywords : azides * click reactions * fluorine * perfluoroalkanes * triazoles Subject RIV: CC - Organic Chemistry Impact factor: 11.994, year: 2016 http://onlinelibrary.wiley.com/doi/10.1002/anie.201609715/full

  6. Synthesis of N-sugar-substituted phthalimides and their derivatives from sugar azides and phthalic anhydride.

    Science.gov (United States)

    Zhang, Su-Na; Li, Zhong-Jun; Cai, Meng-Shen

    2004-06-01

    N-Sugar-substituted phthalimides and tetrachlorophthalimide derivatives can be prepared in good yields under essentially neutral conditions. Mixing a sugar azide, NaI, Me3SiCl, phthalic or substituted phthalic anhydride and tetrabutylammonium iodide as catalyst in acetonitrile at rt or 60 degrees C, afforded 12 imides in 83-95% yields. Copyright 2004 Elsevier Ltd.

  7. Biomolecular patterning of glass surfaces via strain-promoted cycloaddition of azides and cyclooctynes

    NARCIS (Netherlands)

    Wijdeven, M.A.; Nicosia, Carlo; Borrmann, A.; Huskens, Jurriaan; van Delft, F.L.

    2014-01-01

    Metal-free, strain-promoted alkyne–azide cycloaddition (SPAAC) is employed as a versatile technology for the modification of glass with biomolecules. Patterning is executed by stamping of a fluorogenic azidocoumarin or a cyclooctyne to the glass surface, to obtain a unique anchor point for

  8. Copper on Chitosan: A Recyclable Heterogeneous Catalyst for Azide-alkyne Cycloaddition Reactions in Water

    Science.gov (United States)

    Copper sulfate is immobilized over chitosan by simply stirring an aqueous suspension of chitosan in water with copper sulfate; the ensuing catalyst has been utilized for the azide-alkyne cycloaddition in aqueous media and it can be recycled and reused many time without loosing it...

  9. All-in-One azides: empowered click reaction for in vivo labeling and imaging of biomolecules.

    Science.gov (United States)

    Su, Yaning; Li, Li; Wang, Haibin; Wang, Xiaochen; Zhang, Zhiyuan

    2016-02-04

    We designed and synthesized All-in-One (AIO) reactive azide reagents for bioorthogonal reactions with highly efficient Cu(I) ligand moieties, an azido group, and functional tags for imaging or purification. The AIO reagents displayed fast and efficient click ligation and can be applied in a wide range of in vivo systems.

  10. Reaction of Tris(cyclopentadienyl)uranium compounds with amines, azides, and related ligands

    Energy Technology Data Exchange (ETDEWEB)

    Rosen, R.K.

    1989-12-01

    The trivalent uranium compound, (MeC{sub 5}H{sub 4}){sub 3}U(thf), serves as a one- or two-electron reducing agent towards azides, RN{sub 3}. These reactions produce either the uranium(IV) azide, (MeC{sub 5}H{sub 4}){sub 3}UN{sub 3}, or uranium(V) imides, (MeC{sub 5}H{sub 4}){sub 3}UNR. The role of steric and electronic effects upon this reaction has been investigated using several series of azides. For Me{sub 3}XN{sub 3}, the imides are produced when X = C or Si, both products are formed when X = Ge, and the azide is produced when X = Sn. For Ph{sub 3}XN{sub 3}, the azide is produced when X = C or Sn. For Ph{sub 3-x}CH{sub 3}N{sub 3}, the imide is produced when x = 2 and both compounds are produced when x = 1. For substituted phenylazides, RC{sub 6}H{sub 4}N{sub 3}, only the imides are produced. The magnetic properties of uranium diimides, ((MeC{sub 5}H{sub 4}){sub 3}U){sub 2}({mu}-NRN), were investigated. Several uranium(III) amines, (MeC{sub 5}H{sub 4}){sub 3}U(NH{sub 2}R), were produced from (MeC{sub 5}H{sub 4}){sub 3}U(thf) and RNH{sub 2}, and NH{sub 3} was found to be a better ligand towards (MeC{sub 5}H{sub 4}){sub 3}U than is PMe{sub 3}.

  11. Sequential One-Pot Ruthenium-Catalyzed Azide−Alkyne Cycloaddition from Primary Alkyl Halides and Sodium Azide

    KAUST Repository

    Johansson, Johan R.

    2011-04-01

    An experimentally simple sequential one-pot RuAAC reaction, affording 1,5-disubstituted 1H-1,2,3-triazoles in good to excellent yields starting from an alkyl halide, sodium azide, and an alkyne, is reported. The organic azide is formed in situ by treating the primary alkyl halide with sodium azide in DMA under microwave heating. Subsequent addition of [RuClCp*(PPh 3) 2] and the alkyne yielded the desired cycloaddition product after further microwave irradiation. © 2011 American Chemical Society.

  12. 14N NMR Spectroscopy Study of Binding Interaction between Sodium Azide and Hydrated Fullerene

    Directory of Open Access Journals (Sweden)

    Tamar Chachibaia

    2017-04-01

    Full Text Available Our study is the first attempt to study the interaction between NaN3 and hydrated fullerenes C60 by means of a non-chemical reaction-based approach. The aim is to study deviations of signals obtained by 14N NMR spectroscopy to detect the binding interaction between sodium azide and hydrated fullerene. We considered 14N NMR spectroscopy as one of the most suitable methods for the characterization of azides to show resonance signals corresponding to the three non-equivalent nitrogen atoms. The results demonstrate that there are changes in the chemical shift positions and line-broadening, which are related to the different molar ratios of NaN3:C60 in the samples.

  13. Consecutive hydrazino-Ugi-azide reactions: synthesis of acylhydrazines bearing 1,5-disubstituted tetrazoles

    Directory of Open Access Journals (Sweden)

    Angélica de Fátima S. Barreto

    2017-12-01

    Full Text Available Isocyanide-based multicomponent reactions (IMCRs allow the construction of relatively complex molecules through a one-pot synthesis. The combination of IMCRs in a consecutive or sequential fashion further extends the complexity of the molecules obtained. Herein, we report the efficient application of this approach to the synthesis of acylhydrazines bearing 1,5-disubstituted tetrazoles. Our strategy was accomplished in only three steps: first, a one-pot hydrazino-Ugi-azide four-component reaction; second a hydrazinolysis and finally an additional hydrazino-Ugi-azide reaction. This sequence provides the title compounds in moderate to excellent yields. The products synthesized herein contain functional groups within their structures that can be easily modified to obtain new acylhydrazino 1,5-disubstituted tetrazoles.

  14. Azide-derivatized gold nanosphere "clicked" to indium and zinc phthalocyanines for improved nonlinear optical limiting

    Science.gov (United States)

    Bankole, Owolabi M.; Nyokong, Tebello

    2017-05-01

    We report on the conjugation of azide-derivatized gold nanoparticles (AuNPs) to alkyne moieties of ZnPc and InPc via azide-alkyne Huisgen cycloaddition reaction to form phthalocyanines-AuNPs (MPc-AuNPs) conjugates. The detailed structural characterizations of the composites were in good agreement with the expected results. The nonlinear absorption coefficients and other nonlinear optical limiting parameters were almost two times larger for the conjugates compared to free phthalocyanines. We established direct relationship between improved photophysical characterizations and enhanced nonlinear effects of reverse saturable absorption mechanisms favoured by excited triplet absorption of the phthalocyanines in the presence of AuNPs. The combination of InPc with AuNPs resulted in the lowest limiting intensity value of 0.06 J/cm2, hence the best performance in terms of optical limiting.

  15. Azide-water intermolecular coupling measured by 2-color 2D IR spectroscopy

    Directory of Open Access Journals (Sweden)

    Perakis F.

    2013-03-01

    Full Text Available We present 2-color two-dimensional infrared spectroscopy of intermolecular coupling between azide ions and their solvation shell water molecules. The cross-peak between azide asymmetric stretch vibration and the OD-stretch vibration is a result of low- probability uphill population transfer. Narrow bleach/excited state absorption peak shows selectivity to solvation shell water molecules only and the characteristics of the cross-peak suggest that the solvation shell hydrogen bond potential has similar anharmonic properties as the hydrogen bond in ice Ih. Population and depopulation of the excited state of the OD-stretch vibration happen on 150 fs and 1.7 ps timescales, respectively, with early manifesting heating effects that limit the selectivity to population times up to 1 ps.

  16. A fluorogenic probe for the catalyst-free detection of azide-tagged molecules.

    Science.gov (United States)

    Friscourt, Frédéric; Fahrni, Christoph J; Boons, Geert-Jan

    2012-11-14

    Fluorogenic reactions in which non- or weakly fluorescent reagents produce highly fluorescent products can be exploited to detect a broad range of compounds including biomolecules and materials. We describe a modified dibenzocyclooctyne that under catalyst-free conditions undergoes fast strain-promoted cycloadditions with azides to yield strongly fluorescent triazoles. The cycloaddition products are more than 1000-fold brighter compared to the starting cyclooctyne, exhibit large Stokes shift, and can be excited above 350 nm, which is required for many applications. Quantum mechanical calculations indicate that the fluorescence increase upon triazole formation is due to large differences in oscillator strengths of the S(0) ↔ S(1) transitions in the planar C(2v)-symmetric starting material compared to the symmetry-broken and nonplanar cycloaddition products. The new fluorogenic probe was successfully employed for labeling of proteins modified by an azide moiety.

  17. A practical one-pot synthesis of azides directly from alcohols

    Indian Academy of Sciences (India)

    azides, direct methods for the said transformation are only a few. The most familiar and versatile one is the. Mitsunobu displacement,4 where hydrazoic acid is used as ..... Lim J-O, Choi H-K, Suh Y-G, Park H-G, Oh U, Kim. H-D, Park Y-H, Ha H-J, Kin Y-H, Toth A, Wang Y, Tran. R, Pearce L V, Lundberg D J and Blumberg P M ...

  18. 1,3-Dipolar Cycloaddition Reactions of Substituted Benzyl Azides with Acetylenic Compounds

    Directory of Open Access Journals (Sweden)

    Sultan T. Abu-Orabi

    2002-02-01

    Full Text Available We review in this article some of our work which has been published over the last fifteen years in the area of 1,3-dipolar cycloaddition reactions of substituted benzyl azides with acetylenic compounds to form the corresponding 1,2-3-triazoles. Several triazole derivatives were transformed into triazolopyridazine and triazolo-1,3,4-oxadiazole derivatives upon their reactions with hydrazine.

  19. A theoretical study on the reaction pathways and the mechanism of 1,3- dipolar cycloaddition of vinyl acetylene and methyl azide.

    Science.gov (United States)

    Siadati, Seyyed Amir; Mahboobifar, Ali; Nasiri, Ramin

    2014-01-01

    1,3-dipolar cycloaddition procedure is one of the most widely practiced methods in order to synthesize heterocyclic compounds. Although, it seems very simple, but, there are numerous precursors of heterocyclic molecules who have more than one positions to react with a 1,3-dipole species. As a result, while using a precursor with more than one position for reaction, it is probable to synthesize several products with different structures. This paper studies all possible interactions of vinyl acetylene, which has two positions for reaction, with methyl azide. This reaction could lead to the emergence of any 1,3-dipolar cycloaddition products. Our ultimate goal is to help researchers to find out how precursors containing both carbon-carbon double, and the triple bonds interact with 1,3- dipolar species. The present study used the DFT calculations at B3LYP/6-311++G(3df,pd) level to check all probable interactions between vinyl acetylene and methyl azide, and determined Potential Energy Surface, and optimized all species.

  20. Synthesis and Characterization of [60]Fullerene-Glycidyl Azide Polymer and Its Thermal Decomposition

    Directory of Open Access Journals (Sweden)

    Ting Huang

    2015-05-01

    Full Text Available A new functionalized [60]fullerene-glycidyl azide polymer (C60-GAP was synthesized for the first time using a modified Bingel reaction of [60]fullerene (C60 and bromomalonic acid glycidyl azide polymer ester (BM-GAP. The product was characterized by Fourier transform infrared (FTIR, ultraviolet-visible (UV-Vis, and nuclear magnetic resonance spectroscopy (NMR analyses. Results confirmed the successful preparation of C60-GAP. Moreover, the thermal decomposition of C60-GAP was analyzed by differential scanning calorimetry (DSC, thermogravimetric analysis coupled with infrared spectroscopy (TGA-IR, and in situ FTIR. C60-GAP decomposition showed a three-step thermal process. The first step was due to the reaction of the azide group and fullerene at approximately 150 °C. The second step was ascribed to the remainder decomposition of the GAP main chain and N-heterocyclic at approximately 240 °C. The final step was attributed to the burning decomposition of amorphous carbon and carbon cage at around 600 °C.

  1. Synthesis and Luminescence Properties of Iridium(III Azide- and Triazole-Bisterpyridine Complexes

    Directory of Open Access Journals (Sweden)

    Timothy W. Schmidt

    2013-07-01

    Full Text Available We describe here the synthesis of azide-functionalised iridium(III bisterpyridines using the “chemistry on the complex” strategy. The resulting azide-complexes are then used in the copper(I-catalysed azide-alkyne Huisgen 1,3-dipolar cycloaddition “click chemistry” reaction to from the corresponding triazole-functionalised iridium(III bisterpyridines. The photophysical characteristics, including lifetimes, of these compounds were also investigated. Interestingly, oxygen appears to have very little effect on the lifetime of these complexes in aqueous solutions. Unexpectedly, sodium ascorbate acid appears to quench the luminescence of triazole-functionalised iridium(III bisterpyridines, but this effect can be reversed by the addition of copper(II sulfate, which is known to oxidize ascorbate under aerobic conditions. The results demonstrate that iridium(III bisterpyridines can be functionalized for use in “click chemistry” facilitating the use of these photophysically interesting complexes in the modification of polymers or surfaces, to highlight just two possible applications.

  2. Combustion mechanism of high energy composite propellants (V). Combustion of azide/nitramine propellants

    Energy Technology Data Exchange (ETDEWEB)

    Mazaki, H.; Iida, A.; Mitarai, Y. [Asahi Chemical Industry Co. Ltd., Osaka (Japan)

    1998-01-01

    Theoretical and experimental studies have been carried out on the combustion of azide polymers used as a binder in high-energy propellants. AMMO (3-azidemethyl-3`-methyloxetane) is one of the energetic azide polymers which contain N3 groups in their molecular structures. EDNA (ethylenedinitramine) is a linear nitramine which has modest properties in the flame temperature and the molecular weight of burned gases as compared with HMX (cyclotetramethylenetetranitramine) and NQ (nitroguanidine). In this study, the burning rate characteristics of azide/nitramine propellants were investigated in order to gain a wide spectrum of burning rate. As a result, the burning rate of AMMO/EDNA propellant is higher than that of AMMO/HMX propellant and the pressure exponent of AMMO/EDNA propellant is lower than that of AMMO/HMX propellant. Both AMMO/EDNA and AMMO/HMX propellants exhibited the same combustion wave structure as inert polymer/nitramine propellants. The burning surface temperature and the temperature at the end of the first-stage reaction zone for AMMO/EDNA and AMMO/HMX propellants are approximately the same in the pressure range between 1.0 and 5.0 MPa. 12 refs., 7 figs., 2 tabs.

  3. A small azide-modified thiazole-based reporter molecule for fluorescence and mass spectrometric detection

    Directory of Open Access Journals (Sweden)

    Stefanie Wolfram

    2014-10-01

    Full Text Available Molecular probes are widely used tools in chemical biology that allow tracing of bioactive metabolites and selective labeling of proteins and other biomacromolecules. A common structural motif for such probes consists of a reporter that can be attached by copper(I-catalyzed 1,2,3-triazole formation between terminal alkynes and azides to a reactive headgroup. Here we introduce the synthesis and application of the new thiazole-based, azide-tagged reporter 4-(3-azidopropoxy-5-(4-bromophenyl-2-(pyridin-2-ylthiazole for fluorescence, UV and mass spectrometry (MS detection. This small fluorescent reporter bears a bromine functionalization facilitating the automated data mining of electrospray ionization MS runs by monitoring for its characteristic isotope signature. We demonstrate the universal utility of the reporter for the detection of an alkyne-modified small molecule by LC–MS and for the visualization of a model protein by in-gel fluorescence. The novel probe advantageously compares with commercially available azide-modified fluorophores and a brominated one. The ease of synthesis, small size, stability, and the universal detection possibilities make it an ideal reporter for activity-based protein profiling and functional metabolic profiling.

  4. A small azide-modified thiazole-based reporter molecule for fluorescence and mass spectrometric detection.

    Science.gov (United States)

    Wolfram, Stefanie; Würfel, Hendryk; Habenicht, Stefanie H; Lembke, Christine; Richter, Phillipp; Birckner, Eckhard; Beckert, Rainer; Pohnert, Georg

    2014-01-01

    Molecular probes are widely used tools in chemical biology that allow tracing of bioactive metabolites and selective labeling of proteins and other biomacromolecules. A common structural motif for such probes consists of a reporter that can be attached by copper(I)-catalyzed 1,2,3-triazole formation between terminal alkynes and azides to a reactive headgroup. Here we introduce the synthesis and application of the new thiazole-based, azide-tagged reporter 4-(3-azidopropoxy)-5-(4-bromophenyl)-2-(pyridin-2-yl)thiazole for fluorescence, UV and mass spectrometry (MS) detection. This small fluorescent reporter bears a bromine functionalization facilitating the automated data mining of electrospray ionization MS runs by monitoring for its characteristic isotope signature. We demonstrate the universal utility of the reporter for the detection of an alkyne-modified small molecule by LC-MS and for the visualization of a model protein by in-gel fluorescence. The novel probe advantageously compares with commercially available azide-modified fluorophores and a brominated one. The ease of synthesis, small size, stability, and the universal detection possibilities make it an ideal reporter for activity-based protein profiling and functional metabolic profiling.

  5. Pressure-accelerated azide-alkyne cycloaddition: micro capillary versus autoclave reactor performance.

    Science.gov (United States)

    Borukhova, Svetlana; Seeger, Andreas D; Noël, Timothy; Wang, Qi; Busch, Markus; Hessel, Volker

    2015-02-01

    Pressure effects on regioselectivity and yield of cycloaddition reactions have been shown to exist. Nevertheless, high pressure synthetic applications with subsequent benefits in the production of natural products are limited by the general availability of the equipment. In addition, the virtues and limitations of microflow equipment under standard conditions are well established. Herein, we apply novel-process-window (NPWs) principles, such as intensification of intrinsic kinetics of a reaction using high temperature, pressure, and concentration, on azide-alkyne cycloaddition towards synthesis of Rufinamide precursor. We applied three main activation methods (i.e., uncatalyzed batch, uncatalyzed flow, and catalyzed flow) on uncatalyzed and catalyzed azide-alkyne cycloaddition. We compare the performance of two reactors, a specialized autoclave batch reactor for high-pressure operation up to 1800 bar and a capillary flow reactor (up to 400 bar). A differentiated and comprehensive picture is given for the two reactors and the three methods of activation. Reaction speedup and consequent increases in space-time yields is achieved, while the process window for favorable operation to selectively produce Rufinamide precursor in good yields is widened. The best conditions thus determined are applied to several azide-alkyne cycloadditions to widen the scope of the presented methodology. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Click functionalization of phenyl-capped bithiophene on azide-terminated self-assembled monolayers

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Yijun; Cui, Jiaxi [Max Planck Institute for Polymer Research (MPIP), Ackermannweg 10, Mainz 55128 (Germany); Ikeda, Taichi, E-mail: IKEDA.Taichi@nims.go.jp [Max Planck Institute for Polymer Research (MPIP), Ackermannweg 10, Mainz 55128 (Germany); Polymer Materials Unit, National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba 305-0044 (Japan)

    2015-11-15

    Graphical abstract: - Highlights: • Electrochemically-active self-assembled monolayers with phenyl-capped bithiophene were prepared. • Post-functionalization method based on click chemistry solved the solubility issue of phenyl-capped thiophene alkanethiol. • The capture and release of the counter anions during the redox reaction were detectable by E-QCM. - Abstract: We immobilized tetra(ethylene glycol)-substituted phenyl-capped bithiophene with alkyne terminals (Ph2TPh-alkyne) on azide-terminated self-assembled monolayers (N{sub 3}-SAMs) by Cu-catalyzed azide-alkyne cycloaddition reaction. Ph2TPh-functionalized SAMs on a gold substrate showed reversible electrochemical response. The surface densities of the azide groups in N{sub 3}-SAMs and Ph2TPh units in Ph2TPh-functionalized SAMs were estimated to be 7.3 ± 0.3 × 10{sup −10} mol cm{sup −2} and 4.6 ± 0.3 × 10{sup −10} mol cm{sup −2}, respectively, by quartz crystal microbalance (QCM). Most of Ph2TPh-alkynes are considered to be anchored on N{sub 3}-SAMs via both terminal groups. Ph2TPh-functionalized SAMs exhibited reversible redox peaks in cyclic voltammetry (CV). In redox reaction, reversible capture and release of the counter anion could be monitored by electrochemical QCM (E-QCM).

  7. Metal Free Azide-Alkyne Click Reaction: Role of Substituents and Heavy Atom Tunneling.

    Science.gov (United States)

    Karmakar, Sharmistha; Datta, Ayan

    2015-09-03

    Metal free click reactions provide an excellent noninvasive tool to modify and understand the processes in biological systems. Release of ring strain in cyclooctynes on reaction with azides on the formation of triazoles results in small activation energies for various intermolecular Huisgen reactions (1-9). Substitution of difluoro groups at the α, α' position of the cyclooctyne ring enhances the rates of cycloadditions by 10 and 20 times for methyl azide and benzyl azide respectively at room temperature. The computed rate enhancement on difluoro substitution using direct dynamical calculations using the canonical variational transition state theory (CVT/CAG) with small curvature tunneling (SCT) corrections are in excellent agreement with the experimental results. For the intramolecular click reaction (10) notwithstanding its much higher activation energy, quantum mechanical tunneling (QMT) enhances the rate of cycloaddition significantly and increases the N(14)/N(15) primary kinetic isotope effect at 298 K. QMT is shown to be rather efficient in 10 due to a thin barrier of ∼2.4 Å. The present study shows that tunneling effects can be significant for intramolecular click reactions.

  8. Clinical and analytical problems of sodium azide poisonings as exemplified by a case of fatal suicidal poisoning

    Directory of Open Access Journals (Sweden)

    Sebastian Rojek

    2016-03-01

    Full Text Available Aim of the study: To present clinical and analytical aspects associated with sodium azide poisoning. The problems were verified on the basis of a case of sodium azide poisoning which was unique due to its circumstances and the development of an analytical method applied for medico-legal practice. Material and methods : The object of the study was a toxicological analysis of biological specimens collected from a woman who ingested two doses of sodium azide purchased over the Internet, in a suicide attempt. After the ingestion of the first dose, the clinical management in the form of symptomatic treatment indicated a possibility of recovery. However, the ingestion of a second dose of the xenobiotic, already in the hospital, caused death. Toxicological findings were obtained with the dedicated technique of gas chromatography-mass spectrometry (GC-EI-MS-MS after extraction combined with derivatization using pentafluorobenzyl bromide (PFBBr. Results : Post-mortem toxicological studies demonstrated sodium azide in the blood (0.18 mg/l and urine (6.50 mg/l samples collected from the woman. Conclusions : Cases of sodium azide poisoning are rare and difficult to treat, but a review of the literature over a longer interval of time shows that they continue to occur. Therefore, case studies of sodium azide poisoning, together with descriptions of research methodology, can be useful both in clinical terms and in the preparation of toxicological expert opinions for medico-legal purposes.

  9. Luminescence study of lanthanide(III) ions in non-aqueous solutions containing azide ions

    Energy Technology Data Exchange (ETDEWEB)

    Lis, S.; Kimura, T.; Yoshida, Z.; But, S

    2004-10-20

    Luminescence lifetime and intensity measurements of lanthanide(III) ions, Ln{sup 3+} (Eu, Gd and Tb), in non-aqueous solutions containing azide ions (N{sub 3}{sup -}) have been performed to study the quenching effect of N{sub 3}{sup -} using time-resolved laser-induced luminescence spectroscopy and conventional luminescence spectroscopy. The luminescence Stern-Volmer quenching constants K{sub sv}{sup P}HI and azide non-radiative decay constants k{sub N{sub 3}} of the excited Eu(III) ion in the presence of N{sub 3}{sup -} were measured in N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methylformamide (NMF), formamide (FA) and methanol (MeOH). The obtained quenching effect of the Ln{sup 3+} luminescence by azide in the non-aqueous solvents shows the order: Gd>Eu>Tb, which does not obey the energy gap law, {delta}E, between the emitting and the ground state of the Ln{sup 3+} ion (Gd>Tb>Eu). The anomaly in the quenching pattern observed in the case of Eu{sup 3+} can be attributed to its partial reduction to Eu{sup 2+}, additionally to the energy transfer from excited state of Eu{sup 3+} to N{sub 3}{sup -}. The values of quenching rate constants k{sub N{sub 3}} measured for Eu{sup 3+} in various solutions depend on the acceptor number (AN) of the solvents used.

  10. Carbohydrate conjugation through microwave-assisted functionalization of single-walled carbon nanotubes using perfluorophenyl azides.

    Science.gov (United States)

    Kong, Na; Shimpi, Manishkumar R; Ramström, Olof; Yan, Mingdi

    2015-03-20

    Carbohydrate-functionalized single-walled carbon nanotubes (SWNTs) were synthesized using microwave-assisted reaction of perfluorophenyl azide with the nanotubes. The results showed that microwave radiation provides a rapid and effective means to covalently attach carbohydrates to SWNTs, producing carbohydrate-SWNT conjugates for biorecognition. The carbohydrate-functionalized SWNTs were furthermore shown to interact specifically with cognate carbohydrate-specific proteins (lectins), resulting in predicted recognition patterns. The carbohydrate-presenting SWNTs constitute a new platform for sensitive protein- or cell recognition, which pave the way for glycoconjugated carbon nanomaterials in biorecognition applications. Copyright © 2014 Elsevier Ltd. All rights reserved.

  11. Azide- and Alkyne-Functionalised α- and β3-Amino Acids

    DEFF Research Database (Denmark)

    Sminia, T.J.; Pedersen, Daniel Sejer

    2012-01-01

    The synthesis and full characterisation of bifunctional β -amino acids that have side chains functionalised with terminal azides (S)-4 and (R)-4 or acetylenes 5 and 6 is reported for the first time. The building blocks incorporate a turn-inducing β -segment and a side chain that can...... be functionalised further, for example, through copper-catalysed Huisgen cycloaddition. Moreover, the corresponding α-amino acids 1 and 3 have been synthesised and characterised. All amino acid building blocks were of high optical purity as demonstrated by derivatisation and subsequent NMR analysis....

  12. Sodium Azide

    Science.gov (United States)

    ... Mercury (Organic) Case Definition: Mercury (Inorganic) Case Definition: Mercury (Elemental) Methyl bromide Case Definition: Methyl Bromide Poisoning Methyl isocyanate Case Definition: Methyl Isocyanate Poisoning Mustard ...

  13. Room Temperature Activation of Aryloxysulfonyl Azides by [Co(II)(TPP)] for Selective Radical Aziridination of Alkenes via Metalloradical Catalysis.

    Science.gov (United States)

    Subbarayan, Velusamy; Jin, Li-Mei; Xin, Cui; Zhang, X Peter

    2015-06-03

    Aryloxysulfonyl azides can be effectively activated by commercially available cobalt(II) complex of meso-tetraphenylporphyrin ([Co(TPP)]) at room temperature under neutral and nonoxidative conditions for selective radical aziridination of alkenes via metalloradical catalysis. The [Co(TPP)]-catalyzed radical aziridination system is suitable for different combinations of olefin substrates and aryloxysulfonyl azides, producing various N-aryloxysulfonyl aziridine derivatives in good to excellent yields. In addition to generating the environmentally benign N2 as the only byproduct, this Co(II)-based metalloradical aziridination process features mild reaction conditions and operational simplicity.

  14. Solid-phase synthesis of NH-1,2,3-triazoles using 4,4′- bismethoxybenzhydryl azide

    DEFF Research Database (Denmark)

    Cohrt, Anders Emil O'Hanlon; Le Quement, Sebastian Thordal; Nielsen, Thomas Eiland

    2014-01-01

    Readily available 4,4′-bismethoxybenzhydryl azide was found to be a useful building block for the synthesis of NH-1,2,3-triazoles through copper(I)-catalyzed cycloaddition reactions with solid-supported terminal alkynes, followed by acid-mediated deprotection. Peptide-containing NH-1,2,3-triazoles...

  15. A highly active and magnetically recoverable tris(triazolyl)-Cu(I) catalyst for alkyne-azide cycloaddition reactions.

    Science.gov (United States)

    Wang, Dong; Etienne, Laetitia; Echeverria, María; Moya, Sergio; Astruc, Didier

    2014-04-01

    Nanoparticle-supported tris(triazolyl)-CuBr, with a diameter of approximately 25 nm measured by TEM spectroscopy, has been easily prepared, and its catalytic activity was evaluated in the copper-catalyzed azide-alkyne cycloaddition (CuAAC) reaction. In initial experiments, 0.5 mol % loading successfully promoted the CuAAC reaction between benzyl azide and phenylacetylene, in water at room temperature (25 °C). During this process, the iron oxide nanoparticle-supported tris(triazolyl)-CuBr displayed good monodispersity, excellent recoverability, and outstanding reusability. Indeed, it was simply collected and separated from the reaction medium by using an external magnet, then used for another five catalytic cycles without significant loss of catalytic activity. Inductively coupled plasma (ICP) analysis for the first cycle revealed that the amount of copper leached from the catalyst into the reaction medium is negligible (1.5 ppm). The substrate scope has been examined, and it was found that the procedure can be successfully extended to various organic azides and alkynes and can also be applied to the one-pot synthesis of triazoles, through a cascade reaction involving benzyl bromides, alkynes, and sodium azide. In addition, the catalyst was shown to be an efficient CuAAC catalyst for the synthesis of allyl- and TEG-ended (TEG=triethylene glycol) 27-branch dendrimers. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Surface Modification of Poly(divinylbenzene) Microspheres via Thiol-Ene Chemistry and Alkyne-Azide Click Reactions

    NARCIS (Netherlands)

    Goldmann, Anja S.; Walther, Andreas; Nebhani, Leena; Joso, Raymond; Ernst, Dominique; Loos, Katja; Barner-Kowollik, Christopher; Barner, Leonie; Mueller, Axel H. E.; Müller, Axel H.E.

    2009-01-01

    We report the functionalization of cross-linked poly(divinylbenzene) (pDVB) microspheres using both thiol-ene chemistry and azide-alkyne click reactions. The RAFT technique was carried out to synthesize SH-functionalized poly(N-isopropylacrylimide) (pNIPAAm) and utilized to generate pNIPAAm

  17. Sensitive Western-Blot Analysis of Azide-Tagged Protein Post Translational Modifications Using Thermoresponsive Polymer Self-Assembly.

    Science.gov (United States)

    Liu, Tong; Zhang, Wanjun; Zhang, Zheng; Chen, Mingli; Wang, Jianhua; Qian, Xiaohong; Qin, Weijie

    2018-02-06

    Western-blot (WB) is a powerful analytical technique for protein identification in complex biological samples and has been widely used in biological studies for decades. Detection specificity and sensitivity of WB largely relies on quality of the antibodies and performance of the conjugated HRP. However, the application of WB analysis for the detection of protein post-translational modifications (PTMs) is hampered by the low abundance of protein PTMs and by the limited availability of antibodies that specifically differentiate various kinds of PTMs from their protein substrates. Therefore, new recognition mechanisms and signal amplification strategies for WB analysis of protein PTMs is in high demand. In this work, we prepared a soluble polymer that detects various azide-tagged PTM proteins in WB analysis using triarylphosphine and HRP modified thermoresponsive polymer. Specific and efficient detection of azide-tagged PTM protein is achieved via the bioorthogonal reaction between azide and triarylphosphine. More importantly, the chemiluminiscent signal in the WB analysis is largely amplified by the temperature induced self-assembly of numerous thermoresponsive polymer chains carrying multiple HRPs. As a result, approximately 100 times more sensitive detection than commercial antibodies is achieved by this method using standard PTM proteins. Though, this new reagent does not directly detect native PTMs in cell, tissue or blood samples, it still has important application potential in protein PTM studies, considering the wide availability of azide-tagging techniques to a variety of PTMs.

  18. Evidence for sodium azide as an artifact mediating the modulation of inducible nitric oxide synthase by C-reactive protein.

    Science.gov (United States)

    Lafuente, Nuria; Azcutia, Verónica; Matesanz, Nuria; Cercas, Elena; Rodríguez-Mañas, Leocadio; Sánchez-Ferrer, Carlos F; Peiró, Concepción

    2005-03-01

    C-reactive protein (CRP) is an acute-phase protein identified as a cardiovascular risk marker. In recent years, an increasing number of studies have investigated the possible direct effects of CRP on the vasculature, using mainly commercial CRP. In the present work, a potential role for CRP as a modulator of inducible nitric oxide synthase (iNOS) induction was explored. Cultured human aortic vascular smooth muscle cells (HASMC) were stimulated for 18 hours with 10 ng/mL interleukin-1beta (IL-1beta), resulting in a marked increase of iNOS levels and NO production, as determined by Western blotting and nitrite measurement, respectively. Commercial CRP (1 to 100 microg/mL) concentration-dependently inhibited the effects elicited by IL-1beta. Unexpectedly, similar results were observed when the commercial CRP solution was replaced by the corresponding vehicle medium containing growing concentrations of sodium azide. The inhibitory effects of commercial CRP or vehicle medium were lost on sodium azide removal by dialysis. In conclusion, sodium azide from the commercial CRP solution, but not CRP itself, mainly accounts for the inhibitory effect on IL-1beta-evoked iNOS induction and NO release. Care should be taken before attributing any biologic role to commercial CRP containing sodium azide.

  19. MORPHOLOGICAL CHARACTERS OF CHILLI PEPPER (Capsicum frutescens L. AS INFLUENCED BY SODIUM AZIDE AT GENERATIVE STAGE OF M1 GENERATION

    Directory of Open Access Journals (Sweden)

    I Gusti Agung Eka Saraswati

    2013-04-01

    Full Text Available Chili pepper (Capsicum frutescens L. is one vegetable crop that has high economic value.  There are several problems in cultivation of chili pepper, for examples limited land, bad weather, and pests and diseases, which result in low production. These problems can be solved by developing new cultivar which has superior quality.  New cultivars of chili pepper plants can be obtained through induced mutation using chemical mutagen. In this research sodium azide (NaN3 was used as mutagen in chili pepper in order to obtain genetic variations that are useful in  increasing its  production.  The research was designed in  randomized  block  design. The observations were made on the response of plant morphology at generative stage, including plant height, number of branch, number of leaf, leaf length and leaf width.  The results showed that sodium azide increased plant height, branch number, leaf number and leaf length.  Sodium azide at concentrations of 2 mM and 5 mM were most effective in increasing plant height, number of leaves and number of branches. Keywords: Capsicum frutescens L., morphology, mutation, sodium azide

  20. Preparation of glycosyl thiourea derivatives from glycosyl azides using sulfamic acid and sodium iodide in one-pot.

    Science.gov (United States)

    Gucchait, Arin; Jana, Manas; Jana, Kuladip; Misra, Anup Kumar

    2016-11-03

    Novel one-pot reaction conditions have been developed for the preparation of glycosyl thiourea derivatives directly from glycosyl azides mediated by a combination of sulfamic acid and sodium iodide. The reaction conditions were clean, non-toxic and the products were isolated in good to excellent yield. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Lithium Azide as an Electrolyte Additive for All-Solid-State Lithium-Sulfur Batteries.

    Science.gov (United States)

    Eshetu, Gebrekidan Gebresilassie; Judez, Xabier; Li, Chunmei; Bondarchuk, Oleksandr; Rodriguez-Martinez, Lide M; Zhang, Heng; Armand, Michel

    2017-11-27

    Of the various beyond-lithium-ion battery technologies, lithium-sulfur (Li-S) batteries have an appealing theoretical energy density and are being intensely investigated as next-generation rechargeable lithium-metal batteries. However, the stability of the lithium-metal (Li°) anode is among the most urgent challenges that need to be addressed to ensure the long-term stability of Li-S batteries. Herein, we report lithium azide (LiN3 ) as a novel electrolyte additive for all-solid-state Li-S batteries (ASSLSBs). It results in the formation of a thin, compact and highly conductive passivation layer on the Li° anode, thereby avoiding dendrite formation, and polysulfide shuttling. It greatly enhances the cycling performance, Coulombic and energy efficiencies of ASSLSBs, outperforming the state-of-the-art additive lithium nitrate (LiNO3 ). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Azide-Alkyne Huisgen [3+2] Cycloaddition Using CuO Nanoparticles

    Directory of Open Access Journals (Sweden)

    Hyunjoon Song

    2012-11-01

    Full Text Available Recent developments in the synthesis of CuO nanoparticles (NPs and their application to the [3+2] cycloaddition of azides with terminal alkynes are reviewed. With respect to the importance of click chemistry, CuO hollow NPs, CuO hollow NPs on acetylene black, water-soluble double-hydrophilic block copolymer (DHBC nanoreactors and ZnO–CuO hybrid NPs were synthesized. Non-conventional energy sources such as microwaves and ultrasound were also applied to these click reactions, and good catalytic activity with high regioselectivity was observed. CuO hollow NPs on acetylene black can be recycled nine times without any loss of activity, and water-soluble DHBC nanoreactors have been developed for an environmentally friendly process.

  3. Synthesis, solid-state structure, and bonding analysis of a homoleptic beryllium azide

    Energy Technology Data Exchange (ETDEWEB)

    Naglav, Dominik; Tobey, Briac; Lyhs, Benjamin; Roemer, Beate; Blaeser, Dieter; Woelper, Christoph; Jansen, Georg; Schulz, Stephan [Faculty of Chemistry and Center for Nanointegration Duisburg-Essen (Cenide), Duisburg-Essen Univ., Essen (Germany)

    2017-07-10

    [Ph{sub 4}P]{sub 2}[Be(N{sub 3}){sub 4}] (1) and [PNP]{sub 2}[Be(N{sub 3}){sub 4}] (2; PNP=Ph{sub 3}PNPPh{sub 3}) were synthesized by reacting Be(N{sub 3}){sub 2} with [Ph{sub 4}P]N{sub 3} and [PNP]N{sub 3}. Compound 1 represents the first structurally characterized homoleptic beryllium azide. The electronic structure and bonding situation in the tetraazidoberyllate dianion [Be(N{sub 3}){sub 4}]{sup 2-} were investigated by quantum-chemical calculations (NPA, ELF, LOL). (copyright 2017 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Electronic effects of ruthenium-catalyzed [3+2]-cycloaddition of alkynes and azides

    KAUST Repository

    Hou, Duenren

    2010-11-01

    A combined experimental and theoretical study of ruthenium-catalyzed azide-alkyne cycloaddition (RuAAC) reactions is presented and various electronic analyses were conducted to provide a basis in understanding the observed regioselectivity of the 1,2,3-triazole products. Computational studies using density functional theory (DFT) and atoms in molecules quantum theory (AIM) further yield fresh details on the electronic factors that determine the regioselectivity in the RuAAC. It is found that the formation of 1,2,3-triazole products is irreversible and from the Hammett study, the pathway involving a vinyl cationic intermediate is ruled out. The electronic effect favors the formation of 5-electron-donating-group substituted-1,2,3-trizoles. © 2010 Elsevier Ltd. All rights reserved.

  5. Millimeter-Wave Spectroscopy of Formyl Azide (HC(O)N_3)

    Science.gov (United States)

    Walters, Nicholas A.; Amberger, Brent K.; Esselman, Brian J.; Woods, R. Claude; McMahon, Robert J.

    2015-06-01

    Formyl azide (HC(O)N_3) is a highly unstable molecule (t1/2˜2 hours at room temperature as a gas) that has only recently been studied spectroscopically by UV, IR, Raman and NMR methods. We have synthesized formyl azide and obtained its absorption spectrum at room temperature over the range 250-360 GHz. As in the case of carbonyl diazide, two conformers are expected for HC(O)N_3, with the syn-isomer 2.8 kcal/mol lower in energy than the anti-isomer (CCSD(T)/ANO1). Calculations at the same level of theory and the same basis set predict the dipole moments for the syn-isomer (μ = 1.56 D) and anti-isomer (μ = 2.56 D). These calculations also indicate that b-type transitions should dominate the syn-isomer spectrum, while a-type transitions become more significant in the case of the anti-isomer. Despite the anti-isomer having a larger dipole moment, the syn-isomer still gives rise to all the dominant features of the spectrum. Thus far, five vibrational states (νb{9}, νb{12}, 2νb{9}, νb{9} + νb{12}, νb{11}) have been studied for the syn-isomer, with the highest energy state νb{11} = 582.6 wn. Searches for the spectra of the anti-isomer are ongoing. Banert, K. et al. Angew. Chem. Int. Ed. 2012, 51, 4718-4721 Zeng, X. et al. Angew. Chem. Int. Ed. 2013, 52, 3503-3506 Amberger, B.K. et al. J. Mol. Spectrosc. 259, (2014) 15-20

  6. Azide protection of bacteroides superoxide dismutases from inactivation by hydrogen peroxide

    Energy Technology Data Exchange (ETDEWEB)

    Barkley, K.B.; Gregory, E.M.

    1986-05-01

    The anaerobes Bacteroides fragilis, B. distasonis and B. thetaiotaomicron produce an iron-containing superoxide dismutase (FeSOD). These FeSODs are reversibly inhibited by 1 mM azide (NaN/sub 3/) and are irreversibly inactivated upon incubation with hydrogen peroxide (H/sub 2/O/sub 2/). H/sub 2/O/sub 2/ inactivation of the enzyme likely depends on a Fenton type reaction with the production of hydroxyl radical (OH). Addition of NaN/sub 3/ to the enzyme solution decreased the rate of inactivation by H/sub 2/O/sub 2/. After 20 minutes incubation of purified B. distasonis FeSOD with 2.5 mM H/sub 2/O/sub 2/, 61% of the initial enzymatic activity remained when 1 mM NaN/sub 3/ was also present compared with 29% activity without NaN/sub 3/. Similar results were seen with FeSOD from B. fragilis and B. thetaiotaomicron. Metal analyses of the native, peroxidized, and NaN/sub 3/ protected samples are consistent with loss of Fe from the enzyme upon peroxidation, but retention of Fe and enzymatic activity in the NaN/sub 3/ protected sample. Protection of FeSOD activity from H/sub 2/O/sub 2/ inactivation was dependent on NaN/sub 3/ concentration. Anionic hydroxyl radical scavengers, such as urate and xanthine did not significantly protect the enzyme. The results are consistent with binding of azide to the active site either preventing entry of H/sub 2/O/sub 2/ or altering Fe redox potential, preventing OH production.

  7. Synthesis of Dendronized Poly(l-Glutamate via Azide-Alkyne Click Chemistry

    Directory of Open Access Journals (Sweden)

    Peter Perdih

    2016-03-01

    Full Text Available Poly(l-glutamate (PGlu was modified with a second-generation dendron to obtain the dendronized polyglutamate, P(Glu-D. Synthesized P(Glu-D exhibited a degree of polymerization (DPn of 46 and a 43% degree of dendronization. Perfect agreement was found between the P(Glu-D expected structure and the results of nuclear magnetic resonance spectroscopy (NMR and size-exclusion chromatography coupled to a multi-angle light-scattering detector (SEC-MALS analysis. The PGlu precursor was modified by coupling with a bifunctional building block (N3-Pr-NH2 in the presence of 4-(4,6-dimethoxy-1,3,5-triazin-2-yl-4-methylmorpholinium chloride (DMTMM coupling reagent. The second-generation polyamide dendron was prepared by a stepwise procedure involving the coupling of propargylamine to the l-lysine carboxyl group, followed by attaching the protected 2,2-bis(methylolpropionic acid (bis-MPA building block to the l-lysine amino groups. The hydroxyl groups of the resulting second-generation dendron were quantitatively deprotected under mild acidic conditions. The deprotected dendron with an acetylene focal group was coupled to the pendant azide groups of the modified linear copolypeptide, P(Glu-N3, in a Cu(I catalyzed azide-alkyne cycloaddition reaction to form a 1,4-disubstituted triazole. The dendronization reaction proceeded quantitatively in 48 hours in aqueous medium as confirmed by 1H NMR and Fourier transform infrared spectroscopy (FT-IR spectroscopy.

  8. Site-selective azide incorporation into endogenous RNase A via a "chemistry" approach.

    Science.gov (United States)

    Chen, Xi; Henschke, Lars; Wu, Qianzhen; Muthoosamy, Kasturi; Neumann, Boris; Weil, Tanja

    2013-01-14

    Site-selective labeling of endogenous proteins represents a major challenge in chemical biology, mainly due to the absence of unique reactive groups that can be addressed selectively. Recently, we have shown that surface-exposed lysine residues of two endogenous proteins and a peptide exhibit subtle changes in their individual reactivities. This feature allows the modification of a single residue in a highly site-selective fashion if kinetically controlled labeling conditions are applied. In order to broaden the scope of the "kinetically-controlled protein labeling" (KPL) approach and highlight additional applications, the water-soluble bioorthogonal reagent, biotin-TEO-azido-NHS (11), is developed which enables the site-selective introduction of an azido group onto endogenous proteins/peptides. This bioconjugation reagent features a biotin tag for affinity purification, an azido group for bioorthogonal labeling, a TEO (tetraethylene oxide) linker acting as a spacer and to impart water solubility and an N-hydroxysuccinimidyl (NHS) ester group for reacting with the exposed lysine residue. As a proof of concept, the native protein ribonuclease A (RNase A) bearing ten available lysine residues at the surface is furnished with a single azido group at Lys 1 in a highly site-selective fashion yielding azido-(K1)RNase A. The K1 site-selectivity is demonstrated by the combined application and interpretation of high resolution MALDI-ToF mass spectroscopy, tandem mass spectroscopy and extracted ion chromatography (XIC). Finally, the water soluble azide-reactive phosphine probe, rho-TEO-phosphine (21) (rho: rhodamine), has been designed and applied to attach a chromophore to azido-(K1)RNase A via Staudinger ligation at physiological pH indicating that the introduced azido group is accessible and could be addressed by other established azide-reactive bioorthogonal reaction schemes.

  9. Mono and dinuclear arene ruthenium(II) triazoles by 1,3-dipolar cycloadditions to a coordinated azide in ruthenium(II) compounds

    Digital Repository Service at National Institute of Oceanography (India)

    Singh, K.S.; Svitlyk, V.; Mozharivskyj, Y.

    reaction of [(η 6 - C 6 Me 6 )Ru(L 2 )Cl] with sodium azide. Notably, as mentioned earlier, a direct reaction of [(η 6 -C 6 Me 6 ) Ru(L 1 )Cl] (1) with NaN 3 in ethanol yielded tetra azido compound of formulation [{(η 6 - C 6 Me 6 )Ru(N 3 )(N 3 )} 2... sodium azide. As a part of our study on arene ruthenium (II) azide compounds, 11 herein, we would like to report, the synthesis of (η 6 -C 6 Me 6 ) ruthenium (II) azido compound 2 and the subsequent 1,3-dipolar cycloaddition reaction of 1 and 2...

  10. CATIONIC POLYMERIZATION OF 1,3-PENTADIENE INITIATED BY ORGANIC AZIDE/Et2AlCl

    Institute of Scientific and Technical Information of China (English)

    PENG Yuxing; DAI Hansong; LIU Jialin; CUN Linfeng

    1995-01-01

    The cationic polymerization of 1,3-pentadiene was initiated by the organic azide/Et2AlCl initiating system in CH2Cl2 and n-hexane. The polymerizations were also carried out in parallel with organic chloride/Et2AlCl and Et2AlCl alone for comparison. The Et2AlCl- induced polymerization gives a low yield while the polymerization initiated by organic chloride/Et2AlCl produces mainly insoluble product. In contrast, the polymerization with azide/Et2AlCl has a high conversion and the resulting polymer having a high molecular weight is totally soluble. The SEC spectra of the polymers have clearly shown the differences between these initiating systems.

  11. Regioselective Sequential Modification of Chitosan via Azide-Alkyne Click Reaction: Synthesis, Characterization, and Antimicrobial Activity of Chitosan Derivatives and Nanoparticles

    OpenAIRE

    Atif Sarwar; Haliza Katas; Siti Noradila Samsudin; Noraziah Mohamad Zin

    2015-01-01

    Recently, the attention of researchers has been drawn toward the synthesis of chitosan derivatives and their nanoparticles with enhanced antimicrobial activities. In this study, chitosan derivatives with different azides and alkyne groups were synthesized using click chemistry, and these were further transformed into nanoparticles by using the ionotropic gelation method. A series of chitosan derivatives was successfully synthesized by regioselective modification of chitosan via an azide-alkyn...

  12. The orbital ground state of the azide-substrate complex of human heme oxygenase is an indicator of distal H-bonding: implications for the enzyme mechanism.

    Science.gov (United States)

    Ogura, Hiroshi; Evans, John P; Peng, Dungeng; Satterlee, James D; Ortiz de Montellano, Paul R; La Mar, Gerd N

    2009-04-14

    The active site electronic structure of the azide complex of substrate-bound human heme oxygenase 1 (hHO) has been investigated by (1)H NMR spectroscopy to shed light on the orbital/spin ground state as an indicator of the unique distal pocket environment of the enzyme. Two-dimensional (1)H NMR assignments of the substrate and substrate-contact residue signals reveal a pattern of substrate methyl contact shifts that places the lone iron pi-spin in the d(xz) orbital, rather than the d(yz) orbital found in the cyanide complex. Comparison of iron spin relaxivity, magnetic anisotropy, and magnetic susceptibilities argues for a low-spin, (d(xy))(2)(d(yz),d(xz))(3), ground state in both azide and cyanide complexes. The switch from singly occupied d(yz) for the cyanide to d(xz) for the azide complex of hHO is shown to be consistent with the orbital hole determined by the azide pi-plane in the latter complex, which is approximately 90 degrees in-plane rotated from that of the imidazole pi-plane. The induction of the altered orbital ground state in the azide relative to the cyanide hHO complex, as well as the mean low-field bias of methyl hyperfine shifts and their paramagnetic relaxivity relative to those in globins, indicates that azide exerts a stronger ligand field in hHO than in the globins, or that the distal H-bonding to azide is weaker in hHO than in globins. The Asp140 --> Ala hHO mutant that abolishes activity retains the unusual WT azide complex spin/orbital ground state. The relevance of our findings for other HO complexes and the HO mechanism is discussed.

  13. The orbital ground state of the azide-substrate complex of human heme oxygenase is an indicator of distal H-bonding: Implications for the enzyme mechanism‡

    Science.gov (United States)

    Ogura, Hiroshi; Evans, John P.; Peng, Dungeng; Satterlee, James D.; de Montellano, Paul R. Ortiz; Mar, Gerd N. La

    2009-01-01

    The active site electronic structure of the azide complex of substrate-bound human heme oxygenase-1, (hHO) has been investigated by 1H NMR spectroscopy to shed light on the orbital/spin ground state as an indicator of the unique distal pocket environment of the enzyme. 2D 1H NMR assignments of the substrate and substrate-contact residue signals reveal a pattern of substrate methyl contact shifts, that places the lone iron π-spin in the dxz orbital, rather than the dyz orbital found in the cyanide complex. Comparison of iron spin relaxivity, magnetic anisotropy and magnetic susceptibilities argues for a low-spin, (dxy)2(dyz,dxz)3, ground state in both azide and cyanide complexes. The switch from singly-occupied dyz for the cyanide to dxz for the azide complex of hHO is shown to be consistent with the orbital hole determined by the azide π-plane in the latter complex, which is ∼90° in-plane rotated from that of the imidazole π-plane. The induction of the altered orbital ground state in the azide relative to the cyanide hHO complex, as well as the mean low-field bias of methyl hyperfine shifts and their paramagnetic relaxivity relative to those in globins, indicate that azide exerts a stronger ligand field in hHO than in the globins, or that the distal H-bonding to azide is weaker in hHO than in globins. The Asp140 → Ala hHO mutant that abolishes activity retains the unusual WT azide complex spin/orbital ground state. The relevance of our findings for other HO complexes and the HO mechanism is discussed. PMID:19243105

  14. Copper(I)-Catalyzed Cycloaddition of Bismuth(III) Acetylides with Organic Azides: Synthesis of Stable Triazole Anion Equivalents

    Science.gov (United States)

    Worrell, Brady T.; Ellery, Shelby P.

    2014-01-01

    Readily accessible and shelf-stable 1-bismuth(III) acetylides react rapidly and regiospecifically with organic azides in the presence of a copper(I) catalyst. The reaction tolerates many functional groups and gives excellent yields of the previously unreported, bench-stable 5-bismuth triazolides. This uniquely reactive intermediates can be further functionalized under extremely mild conditions to give fully substituted 1,2,3-triazoles. PMID:24130150

  15. Synthesis of novel bis(perfluorophenyl azides) coupling agents: Evaluation of their performance by crosslinking of poly(ethylene oxide)

    KAUST Repository

    Mehenni, Hakim

    2011-11-01

    Novel bis(perfluorophenyl azides) coupling agents, containing spacer arms from ethylene or ethylene glycol subunits, were successfully synthesized. Nitrenes photogenerated from these novel bis(PFPA) coupling agents were applied successfully to the cross-linking of poly(ethylene oxide) (PEO10,000) in either aqueous medium or at the solid state, thus, we demonstrated the potential of these bis(PFPA) molecules as promising coupling agents in surface engineering. © 2011 Elsevier Ltd. All rights reserved.

  16. Ribosome-Templated Azide-Alkyne Cycloadditions: Synthesis of Potent Macrolide Antibiotics by In Situ Click Chemistry.

    Science.gov (United States)

    Glassford, Ian; Teijaro, Christiana N; Daher, Samer S; Weil, Amy; Small, Meagan C; Redhu, Shiv K; Colussi, Dennis J; Jacobson, Marlene A; Childers, Wayne E; Buttaro, Bettina; Nicholson, Allen W; MacKerell, Alexander D; Cooperman, Barry S; Andrade, Rodrigo B

    2016-03-09

    Over half of all antibiotics target the bacterial ribosome-nature's complex, 2.5 MDa nanomachine responsible for decoding mRNA and synthesizing proteins. Macrolide antibiotics, exemplified by erythromycin, bind the 50S subunit with nM affinity and inhibit protein synthesis by blocking the passage of nascent oligopeptides. Solithromycin (1), a third-generation semisynthetic macrolide discovered by combinatorial copper-catalyzed click chemistry, was synthesized in situ by incubating either E. coli 70S ribosomes or 50S subunits with macrolide-functionalized azide 2 and 3-ethynylaniline (3) precursors. The ribosome-templated in situ click method was expanded from a binary reaction (i.e., one azide and one alkyne) to a six-component reaction (i.e., azide 2 and five alkynes) and ultimately to a 16-component reaction (i.e., azide 2 and 15 alkynes). The extent of triazole formation correlated with ribosome affinity for the anti (1,4)-regioisomers as revealed by measured Kd values. Computational analysis using the site-identification by ligand competitive saturation (SILCS) approach indicated that the relative affinity of the ligands was associated with the alteration of macrolactone+desosamine-ribosome interactions caused by the different alkynes. Protein synthesis inhibition experiments confirmed the mechanism of action. Evaluation of the minimal inhibitory concentrations (MIC) quantified the potency of the in situ click products and demonstrated the efficacy of this method in the triaging and prioritization of potent antibiotics that target the bacterial ribosome. Cell viability assays in human fibroblasts confirmed 2 and four analogues with therapeutic indices for bactericidal activity over in vitro mammalian cytotoxicity as essentially identical to solithromycin (1).

  17. Reaction of azides and enolisable aldehydes under the catalysis of organic bases and Cinchona based quaternary ammonium salts.

    Science.gov (United States)

    Destro, Dario; Sanchez, Sandra; Cortigiani, Mauro; Adamo, Mauro F A

    2017-06-21

    Herein we report a two-step sequence for the preparation of amides starting from azides and enolisable aldehydes. The reaction proceeded via the formation of triazoline intermediates that were converted into amides via Lewis acid catalysis. Preliminary studies on the preparation of triazolines under chiral phase transfer catalysis are also presented, demonstrating that enantioenriched amides could be prepared from achiral aldehydes in moderate to low enantioselectivity.

  18. Sterically biased 3,3-sigmatropic rearrangement of chiral allylic azides: application to the total syntheses of alkaloids.

    Science.gov (United States)

    Lauzon, Sophie; Tremblay, François; Gagnon, David; Godbout, Cédrickx; Chabot, Christine; Mercier-Shanks, Catherine; Perreault, Stéphane; DeSève, Hélène; Spino, Claude

    2008-08-15

    We describe a tandem Mitsunobu/3,3-sigmatropic rearrangement of allylic azides on a chiral auxiliary system that favors one regioisomer thanks to its exceptional steric bias. The sequence may be completed by the oxidative cleavage of the auxiliary or by a ring-closing metathesis reaction that produces a carbo- or heterocycle directly and a recyclable form of the chiral auxiliary. Applications of the methodology to the total synthesis of (+)-coniine, (+)-lentiginosin, and (+)-pumiliotoxin C are reported.

  19. Sterically biased 3,3-sigmatropic rearrangement of azides: efficient preparation of nonracemic alpha-amino acids and heterocycles.

    Science.gov (United States)

    Gagnon, David; Lauzon, Sophie; Godbout, Cédrickx; Spino, Claude

    2005-10-13

    [reaction: see text] Homochiral alpha-amino acids, heterocycles, and carbocycles are efficiently constructed via a short sequence of reactions starting from the chiral auxiliary p-menthane-3-carboxaldehyde. The key feature of the sequence is a highly selective tandem Mitsunobu/3,3-sigmatropic rearrangement of hydrazoic acid that procures enantiomerically enriched allylic azides. The sequence is either terminated by oxidative cleavage to provide amino acids or by ring-closing metathesis to provide heterocycles or carbocycles bearing nitrogen.

  20. Alkyne-Azide Cycloaddition Catalyzed by Silver Chloride and “Abnormal” Silver N-Heterocyclic Carbene Complex

    Science.gov (United States)

    Ortega-Arizmendi, Aldo I.; Aldeco-Pérez, Eugenia; Cuevas-Yañez, Erick

    2013-01-01

    A library of 1,2,3-triazoles was synthesized from diverse alkynes and azides using catalytic amounts of silver chloride instead of copper compounds. In addition, a novel “abnormal” silver N-heterocyclic carbene complex was tested as catalyst in this process. The results suggest that the reaction requires only 0.5% of silver complex, affording 1,2,3-triazoles in good yields. PMID:24307866

  1. +Facile extraction of azide in sartan drugs using magnetized anion-exchange metal-organic frameworks prior to ion chromatography.

    Science.gov (United States)

    Zhang, Sainan; Han, Peipei; Xia, Yan

    2017-09-08

    Quaternary amine functionalized metal-organic framework MIL-101(Cr) (MIL-101(Cr)-NMe3) was prepared as the sorbent for the magnetic solid-phase extraction (MSPE) of azide from sartan drugs before ion chromatography determination. Magnetization of MIL-101-NMe3 were achieved concurrently by adding MIL-101-NMe3 and Fe3O4@SiO2 to the sample solution under ultrasonication. The prepared Fe3O4@SiO2/MIL-101-NMe3 gave the adsorption capacity of 37.5mgg-1. The developed method had a detection limit of 0.24μgL-1 and quantitation limit of 0.79μgL-1 for azide. The relative standard deviations for the intra-day retention time and peak area were 0.52% and 0.36% (n=5), respectively. The developed method was successfully applied for the determination of azide in sartan drugs with the recoveries from 96.5% to 100.5%. Copyright © 2017. Published by Elsevier B.V.

  2. Improved metal-adhesive polymers from copper(I)-catalyzed azide-alkyne cycloaddition.

    Science.gov (United States)

    Accurso, Adrian A; Delaney, Mac; O'Brien, Jeff; Kim, Hyonny; Iovine, Peter M; Díaz Díaz, David; Finn, M G

    2014-08-18

    Electrically conductive adhesive polymers offer many potential advantages relative to Sn-Pb solders, including reduced toxicity, low cost, low processing temperatures, and the ability to make application-specific formulations. Polymers generated from the copper(I)-catalyzed cycloaddition (CuAAC) reaction between multivalent azides and alkynes have previously been identified as strong metal-binding adhesives. Herein we demonstrate that the performance of these materials can be remarkably improved by the incorporation of a flexibility-inducing difunctionalized component and a tertiary amine additive in optimized concentrations. The best formulations were identified by means of rapid adhesion testing of a library of potential candidates by using a custom-built instrument and validated in an American Society for Testing and Materials (ASTM)-standard lap-shear test. Characteristic phase transitions were identified by differential scanning calorimetry (DSC) for adhesives with and without the additives as a function of curing temperature. The incorporation of flexible components was found to more than double the strength of the adhesive. Moreover, the adhesive was made electrically conductive by the inclusion of 20 wt% silver-coated copper flakes and further improved in this regard by the incorporation of multiwalled carbon nanotubes in the formulation. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Azide-based cross-linking of polymers of intrinsic microporosity (PIMs) for condensable gas separation

    KAUST Repository

    Du, Naiying

    2011-03-11

    Cross-linked polymers of intrinsic microporosity (PIM)s for gas separation membranes, were prepared by a nitrene reaction from a representative PIM in the presence of two different diazide cross-linkers. The reaction temperature was optimized using TGA. The homogenous membranes were cast from THF solutions of different ratios of PIM to azides. The resulting cross-linked structures of the PIMs membranes were formed at 175 °C after 7.5 h and confirmed by TGA, XPS, FT-IR spectroscopy and gel content analysis. These resulting cross-linked polymeric membranes showed excellent gas separation performance and can be used for O 2/N 2 and CO 2/N 2 gas pairs, as well as for condensable gases, such as CO 2/CH 4, propylene/propane separation. Most importantly, and differently from typical gas separation membranes derived from glassy polymers, the crosslinked PIMs showed no obvious CO 2 plasticization up to 20 atm pressure of pure CO 2 and CO 2/CH 4 mixtures. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Hydrophilic block azidation of PCL-b-PEO block copolymers from epichlorohydrin.

    Science.gov (United States)

    Liu, Junjie; Gan, Zhihua

    2014-05-01

    Amphiphilic diblock copolymers poly(ϵ-caprolactone)-b-poly(ethylene oxide) (PCL-b-PEO) with well-controlled pendant azido groups along the hydrophilic PEO block, that is, poly(ϵ-caprolactone)-b-poly(ethylene oxide-co-glycidyl azide) (PCL-b-P(EO-co-GA)), are synthesized from poly(ϵ-caprolactone)-b-poly(ethylene oxide-co-epichlorohydrin) (PCL-b-P(EO-co-ECH)). The further conversion of those azido groups along the hydrophilic block of copolymers into amino or carboxyl groups via click chemistry is studied. The micelles self-assembled from PCL-b-P(EO-co-GA) with azido groups on the shell are crosslinked by the dialkynyl-PEO. The micelles with crosslinked shell show better stability, higher drug loading capacities, subsequent faster drug release rate, and higher cytotoxicity to cancer cells. The introduction of azido groups into PCL-b-PEO amphiphilic diblock copolymers from epichlorohydrin in PEO hydrophilic block in this work provides a new method for biofunctionalization of micelles via mild click chemistry. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Performance Evaluation of Liquid Fuel 2-Dimethyl Amino Ethyl Azide (DMAZ) with Liquid Oxidizers

    Science.gov (United States)

    Pakdehi, Shahram G.; Ajdari, S.; Hashemi, A.; Keshavarz, Mohammad Hossein

    2015-01-01

    2-Dimethyl amino ethyl azide (DMAZ) has attracted much attention as a suitable liquid fuel replacement for monomethyl hydrazine (MMH) and unsymmetrical dimethyl hydrazine (UDMH) in propellant systems because, in contrast to these fuels, it is nontoxic. In this article, performance and ignition delay of DMAZ were studied with common liquid oxidizers including inhibited red fuming nitric acid (IRFNA), anhydrous nitric acid, dinitrogen tetroxide (N2O4), hydrogen peroxide (H2O2), liquid oxygen (LOX), and mixed oxides of nitrogen (MON). Results showed that combustion of DMAZ and LOX provides the highest specific impulse (305.8 s) compared to the other mentioned oxidizers. Moreover, DMAZ and H2O2 gave the highest density specific impulse (360.2 s) at an optimum oxidizer-to-fuel ratio due to the higher density of hydrogen peroxide. Furthermore, a mixture of DMAZ and N2O4 had the minimum ignition delay time (68 ms). Therefore, it seems that the DMAZ-N2O4 propellant combination is suitable for space systems.

  6. Tethering antimicrobial peptides onto chitosan: Optimization of azide-alkyne "click" reaction conditions.

    Science.gov (United States)

    Barbosa, Mariana; Vale, Nuno; Costa, Fabíola M T A; Martins, M Cristina L; Gomes, Paula

    2017-06-01

    Antimicrobial peptides (AMP) are promising alternatives to classical antibiotics, due to their high specificity and potency at low concentrations, and low propensity to elicit pathogen resistance. Immobilization of AMP onto biomaterials is an emergent field of research, towards creation of novel antimicrobial materials able to avoid formation of biofilms on the surfaces of medical devices. Herein, we report the chemical route towards one such material, where chitosan was used as biocompatible carrier for the covalent grafting of Dhvar-5, a well-known potent AMP, via the chemoselective ("click") Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC). The material's structure, as well as peptide loading, were confirmed by Fourier-transformed infra-red (FT-IR) and X-ray photoelectron (XPS) spectroscopies, and by Amino Acid Analysis (AAA), respectively. Results herein reported demonstrate that, with proper optimization, the "click" CuAAC is an attractive approach for the tethering of AMP onto chitosan, in order to create novel antimicrobial materials potentially valuable for biomedical applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Azide-based cross-linking of polymers of intrinsic microporosity (PIMs) for condensable gas separation.

    Science.gov (United States)

    Du, Naiying; Cin, Mauro M Dal-; Pinnau, Ingo; Nicalek, Andrzej; Robertson, Gilles P; Guiver, Michael D

    2011-04-19

    Cross-linked polymers of intrinsic microporosity (PIM)s for gas separation membranes, were prepared by a nitrene reaction from a representative PIM in the presence of two different diazide cross-linkers. The reaction temperature was optimized using TGA. The homogenous membranes were cast from THF solutions of different ratios of PIM to azides. The resulting cross-linked structures of the PIMs membranes were formed at 175 °C after 7.5 h and confirmed by TGA, XPS, FT-IR spectroscopy and gel content analysis. These resulting cross-linked polymeric membranes showed excellent gas separation performance and can be used for O(2) /N(2) and CO(2) /N(2) gas pairs, as well as for condensable gases, such as CO(2) /CH(4) , propylene/propane separation. Most importantly, and differently from typical gas separation membranes derived from glassy polymers, the crosslinked PIMs showed no obvious CO(2) plasticization up to 20 atm pressure of pure CO(2) and CO(2) /CH(4) mixtures. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Photografting of perfluoroalkanes onto polyethylene surfaces via azide/nitrene chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Siegmann, Konstantin, E-mail: konstantin.siegmann@zhaw.ch [Institute of Materials and Process Engineering (IMPE), School of Engineering (SoE), Zurich University of Applied Sciences - ZHAW, Technikumstrasse 9, CH-8401 Winterthur (Switzerland); Inauen, Jan, E-mail: jan.inauen@zhaw.ch [Institute of Materials and Process Engineering (IMPE), School of Engineering (SoE), Zurich University of Applied Sciences - ZHAW, Technikumstrasse 9, CH-8401 Winterthur (Switzerland); Villamaina, Diego, E-mail: diego.villamaina@gmail.com [Visiting scientist at IMPE, Permanent address: Rapidplatz 3, CH-8953 Dietikon (Switzerland); Winkler, Martin, E-mail: martin.winkler@zhaw.ch [Institute of Materials and Process Engineering (IMPE), School of Engineering (SoE), Zurich University of Applied Sciences - ZHAW, Technikumstrasse 9, CH-8401 Winterthur (Switzerland)

    2017-02-28

    The purpose of this study is to render polyethylene surfaces strongly and permanently hydrophobic. Polyethylene is a common plastic and, because of its inertness, difficult to graft. We chose polyethylene as example because of its ubiquity and model character. As graft chains linear perfluoroalkyl residues (−C{sub 4}F{sub 9}, −C{sub 6}F{sub 13}, −C{sub 8}F{sub 17} and −C{sub 10}F{sub 21}) were chosen, and photografting was selected as grafting method. Photolytically generated nitrenes can insert into carbon–hydrogen bonds and are therefore suited for binding to polyethylene. Hydrophobic photo reactive surface modifiers based on azide/nitrene chemistry are designed, synthesized in high yield and characterized. Four new molecules are described. Water contact angles exceeding 110° were achieved on grafted polyethylene. One problem is to demonstrate that the photografted surface modifiers are bound covalently to the polyethylene. Abrasion tests show that all new molecules, when photografted to polyethylene, have a higher abrasion resistance than a polyethylene surface coated with a long-chain perfluoroalkane. Relative abrasion resitances of 1.4, 2.0, 2.1 and 2.5 compared to the fluoroalkane coating were obtained for the four compounds. An abrasion model using ice is developed. Although all four compounds have the same λ{sub max} of 266 nm in acetonitrile solution, their molar extincition coefficients increase from 1.6·10{sup 4} to 2.2·10{sup 4} with increasing length of the fluorotelomer chain. Exitonic coupling of the chromophores of the surface modifiers is observed for specific molecules in the neat state. A linear correlation of water contact angle with fluorine surface content, as measured by photoelectron spectroscopy, in grafted polyethylene surfaces is established.

  9. Non-Catalyzed Click Reactions of ADIBO Derivatives with 5-Methyluridine Azides and Conformational Study of the Resulting Triazoles

    Science.gov (United States)

    Smyslova, Petra; Popa, Igor; Lyčka, Antonín; Tejral, Gracian; Hlavac, Jan

    2015-01-01

    Copper-free click reactions between a dibenzoazocine derivative and azides derived from 5-methyluridine were investigated. The non-catalyzed reaction yielded both regioisomers in an approximately equivalent ratio. The NMR spectra of each regioisomer revealed conformational isomery. The ratio of isomers was dependent on the type of regioisomer and the type of solvent. The synthesis of various analogs, a detailed NMR study and computational modeling provided evidence that the isomery was dependent on the interaction of the azocine and pyrimidine parts. PMID:26673606

  10. A ratiometric fluorescent on-off Zn2+ chemosensor based on a tripropargylamine pyrene azide click adduct.

    Science.gov (United States)

    Ingale, Sachin A; Seela, Frank

    2012-10-19

    A new, easy-to-prepare and highly selective pyrene-linked tris-triazole amine fluorescent chemosensor has been designed from tripropargylamine and pyrene azide using Cu(I)-catalyzed click chemistry. The fluorescence on-off sensor 1 is highly selective for Zn(2+) displaying a ratiometric change in emission. The relative intensity ratio of monomer to excimer fluorescence (M(376)/E(465)) of the sensor increases 80-fold upon the addition of 10 equiv of Zn(2+) ions (with a detection limit of 0.2 μM).

  11. Effect of gamma-radiation and sodium azide on quantitative characters in rice (Oryza sativa L.

    Directory of Open Access Journals (Sweden)

    Ricardo Montalván

    1998-03-01

    Full Text Available Seeds of rice cultivar IAC-1246 received single and combined treatments of 10 or 20 Krad gamma-rays and 0.5 mM sodium azide (SA. The experiments were carried out to assess the effect of treatments on the mean and variance in second generation plants of the following quantitative traits: number of days to flowering (NDF, culm length (CL and tiller number (TN. In general, the mutagenic treatments increased variance, but did not change the mean for the characters NDF and CL in the M2 generation. There was no increase in the mean or variance of TN. The combined treatments of gamma-rays and SA resulted in larger variance in CL than for the treatments with gamma-rays alone, but not higher than obtained with SA alone. Combined treatments with gamma-rays and SA did not increase the variance of NDF and TN when compared with the corresponding single treatments.Sementes do cultivar de arroz IAC-1246 receberam tratamento individual e combinado de 10 e 20 Krad de raios-gama e 0,5 de azida sódica (SA. O experimento foi realizado para avaliar o efeito dos tratamentos sobre a média e a variância de plantas M2 nos seguintes caracteres quantitativos: número de dias para a maturação (NDF, comprimento de colmo (CL e número de perfílhos (TN. Em geral, os tratamentos mutagênicos incrementaram a variância, sem mudar a média para os caracteres NDF e CL na geração M2. Todavia, não foi encontrado nenhum incremento seja para a média ou para a variância no caráter TN. Para o caráter CL, os tratamentos combinados de raios-gama e SA mostraram maior variância que aquela observada no tratamento individual com raios-gama, não sendo superior que aquela correspondente ao tratamento individual com SA. Para os caracteres NDF e TN, os tratamentos combinados de raios-gama e SA não incrementaram a variância, quando comparados aos correspondentes tratamentos individuais.

  12. Lead Test

    Science.gov (United States)

    ... Links Patient Resources For Health Professionals Subscribe Search Lead Send Us Your Feedback Choose Topic At a ... Related Content View Sources Also Known As Blood Lead Test Blood Lead Level BLL Formal Name Lead, ...

  13. Hydrothermal synthesis, characterization, and thermal properties of alumino silicate azide sodalite, Na8[AlSiO4]6(N3)2

    Science.gov (United States)

    Borhade, A. V.; Wakchaure, S. G.; Dholi, A. G.; Kshirsagar, T. A.

    2017-07-01

    First time we report the synthesis, structural characterization and thermal behavior of an unusual N3 - containing alumino-silicate sodalite mineral. Azide sodalite, Na8[AlSiO4]6(N3)2 has been synthesized under hydrothermal conditions at 433 K in steel lined Teflon autoclave. The structural and microstructural properties of azide sodalite mineral was characterized by various methods including FT-IR, XRD, SEM, TGA, and MAS NMR. Crystal structure have been refined by Rietveld method in P\\bar 43n space group, indicating that the N3 - sodalite has cubic in lattice. High temperature study was carried out to see the effect of thermal expansion on cell dimension ( a o) of azide sodalite. Thermal behavior of sodalite was also assessed by thermogravimetric method.

  14. Strain-promoted alkyne azide cycloaddition for the functionalization of poly(amide)-based dendrons and dendrimers.

    Science.gov (United States)

    Ornelas, Cátia; Broichhagen, Johannes; Weck, Marcus

    2010-03-24

    Functionalization of a poly(amido)-based dendron with ethylene glycol chains (PEG) using copper-catalyzed alkyne azide cycloaddition (CuAAC) afforded dendrons with significant levels of copper contaminations, preventing the use of such materials for biological applications. We suggest that the presence of amide, PEG, and triazole functional groups allows for copper complexation, thereby preventing the separation of the copper catalyst from the final dendron. To minimize this problem, synthetic variations on CuAAC including the addition of "click" additives for copper sequestering as well as the use of copper wire as the copper source were investigated. None of these strategies, however, resulted in copper-free products. In contrast, we developed a copper-free strain-promoted alkyne azide cycloaddition (SPAAC) strategy that functionalized poly(amide)-based dendrons and dendrimers with PEG chains quantitatively under mild reaction conditions without any metal contamination. The SPAAC products were characterized by (1)H and (13)C NMR, 2D HSQC and COSY NMR, mass spectrometry, and elemental analysis. This is the first report on the use of SPAAC for dendrimer functionalization, and the results obtained here show that SPAAC is an important tool to the dendrimer and more general biomaterials community for the functionalization of macromolecular structures due to the mild and metal-free reaction conditions, no side products, tolerance toward functional groups, and high yields.

  15. Highly sensitive visual detection of copper (II) using water-soluble azide-functionalized gold nanoparticles and silver enhancement.

    Science.gov (United States)

    Zhang, Zhen; Li, Wenqing; Zhao, Qiuling; Cheng, Ming; Xu, Li; Fang, Xiaohong

    2014-09-15

    A high-sensitive method for the visual detection of copper ions in aqueous solution is developed. The method is based on copper ion-catalyzed 'click' reaction between the water-soluble azide-functionalized gold nanoparticles (AuNPs) and alkyne-modified glass slide. The PEG linker was employed as a stabilizing component along with the terminal azide group to keep the AuNPs stably dispersed in water without the assistance of any organic solvent. In the presence of copper ions, the AuNPs are 'clicked' on the slide, and the darkness of the AuNPs in the sample spot is promoted by silver enhancement process. Only a tiny amount of sample (10 μl) is needed with the detectable concentration down to 62 pM by the commonly used flatbed scanner, which is 2-3 orders of magnitude lower than those in previous reports. The selectivity relative to other potentially interfering ions and the applicability in real samples, human serum and tap water, have also been evaluated. Our method has a good potential in point-of-use applications and environment surveys. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. An Optimized Protocol for the Efficient Radiolabeling of Gold Nanoparticles by Using a 125I-labeled Azide Prosthetic Group.

    Science.gov (United States)

    Jeon, Jongho; Shim, Ha Eun; Mushtaq, Sajid; Choi, Mi Hee; Park, Sang Hyun; Choi, Dae Seong; Jang, Beom-Su

    2016-10-10

    Here, we demonstrate a detailed protocol for the radiosynthesis of a 125I-labeled azide prosthetic group and its application to the efficient radiolabeling of DBCO-group-functionalized gold nanoparticles using a copper-free click reaction. Radioiodination of the stannylated precursor (2) was carried out by using [125I]NaI and chloramine T as an oxidant at room temperature for 15 min. After HPLC purification of the crude product, the purified 125I-labeled azide (1) was obtained with high radiochemical yield (75 ± 10%, n = 8) and excellent radiochemical purity (>99%). For the synthesis of radiolabeled 13-nm-sized gold nanoparticles, the DBCO-functionalized gold nanoparticles (3) were prepared by using a thiolated polyethylene glycol polymer. A copper-free click reaction between 1 and 3 gave the 125I-labeled gold nanoparticles (4) with more than 95% of radiochemical yield as determined by radio-thin-layer chromatography (radio-TLC). These results clearly indicate that the present radiolabeling method using a strain-promoted copper-free click reaction will be useful for the efficient and convenient radiolabeling of DBCO-group-containing nanomaterials.

  17. "Bis-Click" Ligation of DNA: Template-Controlled Assembly, Circularisation and Functionalisation with Bifunctional and Trifunctional Azides.

    Science.gov (United States)

    Yang, Haozhe; Seela, Frank

    2017-03-08

    Ligation and circularisation of oligonucleotides containing terminal triple bonds was performed with bifunctional or trifunctional azides. Both reactions are high yielding. Template-assisted bis-click ligation of two individual non-complementary oligonucleotide strands was accomplished to yield heterodimers exclusively. In this context, the template fulfils two functions: it accelerates the ligation reaction and controls product assembly (heterodimer vs. homodimer formation). Intermolecular bis-click circularisation of one oligonucleotide strand took place without template assistance. For construction of oligonucleotides with terminal triple bonds in the nucleobase side chain, 7- or 5-functionalised 7-deaza-dA and dU residues were used. These oligonucleotides are directly accessible by solid-phase synthesis. When trifunctional azides were employed instead of bifunctional linkers, functionalisation of the remaining azido group was performed with small molecules such as 1-ethynyl pyrene, biotin propargyl amide or with ethynylated oligonucleotides. By this means, branched DNA was constructed. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Facile synthesis of linear-dendritic cholesteryl-poly(epsilon-caprolactone)-b-(L-lysine)(G2) by thiol-ene and azide-alkyne "click" reactions

    DEFF Research Database (Denmark)

    Javakhishvili, Irakli; Binder, W.H.; Tanner, S.

    2010-01-01

    The construction of a linear-dendritic block copolymer consisting of terminal cholesteryl moiety, poly(epsilon-caprolactone), and a second generation L-lysine dendron has been accomplished by the combination of copper(I) catalyzed azide-alkyne and UV-triggered thiol-ene "click" reactions. Ring......-opening polymerization of E-caprolactone initiated by 5-hexyn-1-ol and Mitsunobu coupling with 4-pentenoic acid provide hetero-telechelic poly(epsilon-caprolactone) bearing terminal alkyne and alkene groups. It is then employed in the sequential "click" reactions with the azide-functionalized dendritic wedge...

  19. Versatility of azide in serendipitous assembly of copper(II) magnetic polyclusters.

    Science.gov (United States)

    Mukherjee, Sandip; Mukherjee, Partha Sarathi

    2013-11-19

    Engineering at the molecular level is one of the most exciting new developments for the generation of functional materials. However, the concept of designing polynuclear extended structures from bottom up is still not mature. Although progress has been made with secondary building units (SBUs) in metal organic frameworks (MOFs), the control seems to be just an illusion when it comes to bridging ligands such as the azide ion. When we say that the azido ligand is versatile in its bridging capabilities, what we mean is that it would be difficult to predict or control its bridging properties. However, this kind of serendipity is not always bad news. For example, scientists have shown that the azido ligand can mediate magnetic exchanges between paramagnetic metals in a predictable fashion (usually depending upon the bonding geometries). Therefore, it is a well-respected ligand in polynuclear assemblies. Serendipitous assemblies offer new magnetic structures that we may not otherwise even think about synthesizing. The azido ligand forms a variety of complexes with copper(II) using different blocking amines or pyridine based ligands. Its structural nature changes upon changing the substitution on amine, as well as the amount of blocking ligand. In principle, if we take any of these complexes and provide more coordination sites to the bridging azido ligands by removing a fraction of the blocking ligands, we can get new complexes with intricate structural networks and therefore different magnetic properties with the same components as used for the parent complex. In this Account, we mainly discuss the development of a number of new topological and magnetic exchange systems synthesized using this concept. Not all of these new complexes can be grouped according to their basic building structures or even by the ratio of the metal to blocking ligand. Therefore, we divided the discussion by the nuclearity of the basic building structures. Some of the complexes with the same

  20. Lead Poisoning

    Science.gov (United States)

    Lead is a metal that occurs naturally in the earth's crust. Lead can be found in all parts of our ... from human activities such as mining and manufacturing. Lead used to be in paint; older houses may ...

  1. Antimicrobial photodynamic inactivation with decacationic functionalized fullerenes: oxygen-independent photokilling in presence of azide and new mechanistic insights.

    Science.gov (United States)

    Yin, Rui; Wang, Min; Huang, Ying-Ying; Landi, Giacomo; Vecchio, Daniela; Chiang, Long Y; Hamblin, Michael R

    2015-02-01

    Functionalized fullerenes are gaining wide interest for mediating photodynamic therapy (PDT) of diseases such as cancers and infections. We recently reported the synthesis of two new decacationic fullerene monoadducts: C60[>M(C3N6(+)C3)2]-(I(-))10(LC14) and its derivative with a light-harvesting antenna conjugated as a C60[>CPAF-(MN6(+)C3)2]-(I(-))10 nanostructure (LC15). We studied the ability of these compounds to mediate PDT of human cancer cells in vitro when excited by UVA light or by white light. Here we report the synthesis of a new fullerene derivative C60[>M(C3N6(+)C3)2][>M(C3N6C3)2]-(I(-))10 (LC16 derived from LC14), as a malonate bisadduct containing a covalently bound decatertiary amine arm. We investigated the relative abilities of the three compounds to generate singlet oxygen ((1)O2), hydroxyl radicals (HO·), and hydrogen peroxide (H2O2) after excitation by UVA or by white light. We used three different classes of pathogenic microbial cells (Gram-positive bacterium, methicillin-resistant Staphylococcus aureus (MRSA), Gram-negative bacterium Escherichia coli, and fungal yeast Candida albicans). LC15 was the most powerful broad spectrum antimicrobial fullerenyl photosensitizer (FPS) followed by LC16, and LC14 was least powerful. Killing depended on both fullerene monoadduct concentration and light fluence. UVA was five times more effective than white light for killing, but not for generation of ROS and relative absorption was greater in white spectral region. Bacterial killing was not much inhibited by addition of azide anions and in some cases was potentiated. In the absence of oxygen, microbial photokilling was highly potentiated (up to 5 logs) by the addition of azide anions. We conclude that molecular functional addends that encourage a type I electron-transfer mechanism increase the ability of photoactivated fullerene monoadducts to kill microbial cells. Oxygen-independent photokilling is possible with fullerene monoadducts in the presence of

  2. Antimicrobial photodynamic inactivation with decacationic functionalized fullerenes: oxygen independent photokilling in presence of azide and new mechanistic insights

    Science.gov (United States)

    Yin, Rui; Wang, Min; Huang, Ying-Ying; Landi, Giacomo; Vecchio, Daniela; Chiang, Long Y; Hamblin, Michael R

    2016-01-01

    Functionalized fullerenes are becoming of wide interest to mediate photodynamic therapy (PDT) of diseases such as cancers and infections. We recently reported the synthesis of two new decacationic fullerene monoadducts: C60[>M(C3N6+C3)2]−(I−)10(LC14) and its derivative with a light-harvesting antenna conjugated as a C60[>CPAF-(MN6+C3)2]−(I−)10nanostructure (LC15). We studied the ability of these compounds to mediate PDT of human cancer cells in vitro when excited by UVA light or by white light. Here we report the synthesis of a new fullerene derivative C60[>M(C3N6+C3)2][>M(C3N6C3)2]−(I−)10(LC16 derived from LC14), as a malonatebisadduct containing a covalently-bound deca-tertiary amine arm. We investigated the relative abilities of the three compounds to generate singlet oxygen (1O2), hydroxyl radicals (HO·), and hydrogen peroxide (H2O2) after excitation by UVA or by white light. We used three different classes of pathogenic microbial cells (Gram-positive bacterium, methicillin-resistant Staphylococcus aureus (MRSA), Gram-negative bacterium Escherichia coli, and fungal yeast Candida albicans). LC15 was the most powerful broad spectrum antimicrobial fullerenylphotosensitizer (FPS) followed by LC16 and LC14 was least powerful. Killing depended on both fullerene monoadduct concentration and light fluence. UVA was five times more effective than white light for killing, but not for generation of ROS and relative absorption was greater in white spectral region. Bacterial killing was not much inhibited by addition of azide anions and in some cases was potentiated. In the absence of oxygen, microbial photokilling was highly potentiated (up to 5 logs) by addition of azide anions. We conclude that molecular functional addends that encourage a Type-I electron-transfer mechanism increase the ability of photoactivated fullerene monoadducts to kill microbial cells. Oxygen-independent photokilling is possible with fullerene monoadducts in the presence of azide anions

  3. Traceless Azido Linker for the Solid-Phase Synthesis of NH-1,2,3-Triazoles via Cu-Catalyzed Azide-Alkyne Cycloaddition Reactions

    DEFF Research Database (Denmark)

    Cohrt, Anders Emil; Jensen, Jakob Feldthusen; Nielsen, Thomas Eiland

    2010-01-01

    A broadly useful acid-labile traceless azido linker for the solid-phase synthesis of NH-1,2,3-triazoles is presented. A variety of alkynes were efficiently immobilized on a range of polymeric supports by Cu(I)-mediated azide-alkyne cycloadditions. Supported triazoles showed excellent compatibility...

  4. New and simple synthesis of acid azides, ureas and carbamates from carboxylic acids: application of peptide coupling agents EDC and HBTU.

    Science.gov (United States)

    Sureshbabu, Vommina V; Lalithamba, H S; Narendra, N; Hemantha, H P

    2010-02-21

    Conversion of carboxylic acids into acid azides using peptide coupling agents, EDC and HBTU is described. The procedure is efficient, practical and applicable to a diverse range of carboxylic acids including N-protected amino acids. Using the same reagents, one-pot synthesis of ureas, dipeptidyl urea esters and carbamates from acids has also been achieved.

  5. Ammonium azide: a commented example of an Ab initio structure (Re-) determination from X-ray powder diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Salim de Amorim, H.; Amaral, M.R. do [Instituto de Fisica, Universidade Federal do Rio de Janeiro, CP 68528, 21495-970 Rio de Janeiro (Brazil); Pattison, P. [Institute of Crystallography, BSP, University of Laussane, CH-1015, Laussane (Switzerland); Pereira L, I.; Mendes, J.C. [Departamento de Geologia, Universidade Federal do Rio de Janeiro, 21949-900, Rio de Janeiro (Brazil)

    2002-07-01

    The structure of ammonium azide (NH{sub 4})N{sub 3} was (re-)determined ab initio from x-ray powder diffraction experiment using synchrotron radiation. We tried to detail and comment the different steps involved in the structure determination. The compound crystallize in the orthorhombic Pmna space group (no.53) with a = 8.937(1) A, b= 3.8070(5) A, c = 8.664(1) A, V = 294.79(7) A{sup 3}; Z= 4. It was possible to locate and refine the hydrogen coordinates, in two different approaches, and to establish the H-bonds. The final structural parameters are in good agreement with previous results based on three-dimensional neutron diffraction. (Author)

  6. Solution NMR characterization of magnetic/electronic properties of azide and cyanide-inhibited substrate complexes of human heme oxygenase: implications for steric ligand tilt.

    Science.gov (United States)

    Peng, Dungeng; Ogura, Hiroshi; Ma, Li-Hua; Evans, John P; de Montellano, Paul R Ortiz; La Mar, Gerd N

    2013-04-01

    Solution 2D (1)H NMR was carried out on the azide-ligated substrate complex of human heme oxygenase, hHO, to provide information on the active site molecular structure, chromophore electronic/magnetic properties, and the distal H-bond network linked to the exogenous ligand by catalytically relevant oriented water molecules. While 2D NMR exhibited very similar patterns of two-dimensional nuclear Overhauser spectroscopy cross peaks of residues with substrate and among residues as the previously characterized cyanide complex, significant, broadly distributed chemical shift differences were observed for both labile and non-labile protons. The anisotropy and orientation of the paramagnetic susceptibility tensor, χ, were determined for both the azide and cyanide complexes. The most significant difference observed is the tilt of the major magnetic axes from the heme normal, which is only half as large for the azide than cyanide ligand, with each ligand tilted toward the catalytically cleaved α-meso position. The difference in chemical shifts is quantitatively correlated with differences in dipolar shifts in the respective complexes for all but the distal helix. The necessity of considering dipolar shifts, and hence determination of the orientation/anisotropy of χ, in comparing chemical shifts involving paramagnetic complexes, is emphasized. The analysis shows that the H-bond network cannot detect significant differences in H-bond acceptor properties of cyanide versus azide ligands. Lastly, significant retardation of distal helix labile proton exchange upon replacing cyanide with azide indicates that the dynamic stability of the distal helix is increased upon decreasing the steric interaction of the ligand with the distal helix. Copyright © 2013. Published by Elsevier Inc.

  7. Lead poisoning

    Science.gov (United States)

    ... or dust from lead-based paint. Toys and furniture painted before 1976. Painted toys and decorations made ... by decades of car exhaust or years of house paint scrapings. Lead is more common in soil ...

  8. Lead Poisoning

    Science.gov (United States)

    ... a hard, durable surface. In 1977, federal regulations banned lead from paint for general use. But homes ... OTHERS: Lead has recently been found in some plastic mini-blinds and vertical blinds which were made ...

  9. Relational Leading

    DEFF Research Database (Denmark)

    Larsen, Mette Vinther; Rasmussen, Jørgen Gulddahl

    2015-01-01

    This first chapter presents the exploratory and curious approach to leading as relational processes – an approach that pervades the entire book. We explore leading from a perspective that emphasises the unpredictable challenges and triviality of everyday life, which we consider an interesting......, relevant and realistic way to examine leading. The chapter brings up a number of concepts and contexts as formulated by researchers within the field, and in this way seeks to construct a first understanding of relational leading....

  10. Molecular and electronic structure of chromium(V) nitrido complexes with azide and isothiocyanate ligands

    DEFF Research Database (Denmark)

    Bendix, Jesper; Birk, Torben; Weyhermüller, Thomas

    2005-01-01

    and characterized by single-crystal X-ray diffraction. Reaction of [Cr(N)(NCS)4]2- with 1,10-phenanthroline furnishes six-coordinate [Cr(N)(NCS)3(phen)]- wherein phenanthroline coordinates to the position trans to the nitrido ligand. The trans influence of the nitrido ligand leads to a bond length difference of 0...

  11. Improved synthesis of [(18)F]FLETT via a fully automated vacuum distillation method for [(18)F]2-fluoroethyl azide purification.

    Science.gov (United States)

    Ackermann, Uwe; Plougastel, Lucie; Goh, Yit Wooi; Yeoh, Shinn Dee; Scott, Andrew M

    2014-12-01

    The synthesis of [(18)F]2-fluoroethyl azide and its subsequent click reaction with 5-ethynyl-2'-deoxyuridine (EDU) to form [(18)F]FLETT was performed using an iPhase FlexLab module. The implementation of a vacuum distillation method afforded [(18)F]2-fluoroethyl azide in 87±5.3% radiochemical yield. The use of Cu(CH3CN)4PF6 and TBTA as catalyst enabled us to fully automate the [(18)F]FLETT synthesis without the need for the operator to enter the radiation field. [(18)F]FLETT was produced in higher overall yield (41.3±6.5%) and shorter synthesis time (67min) than with our previously reported manual method (32.5±2.5% in 130min). Copyright © 2014 Elsevier Ltd. All rights reserved.

  12. Facile solid-phase ruthenium assisted azide-alkyne cycloaddition (RuAAC) utilizing the Cp*RuCl(COD)-catalyst

    DEFF Research Database (Denmark)

    Engholm, Ebbe; sgz228, sgz228; Blixt, Klas Ola

    2017-01-01

    The ruthenium assisted azide-alkyne cycloaddition (RuAAC) reaction is a well-established method for the generation of 1,5- and 1,4,5-substituted 1,2,3-triazoles, which we have extended to the solid-phase synthesis of 1,2,3-triazole-peptides. The 1,2,3-triazole moieties were formed upon the reaction...... of alkynes with a solid-phase bound secondary azide in the presence of the Cp*RuCl(COD) catalyst at room temperature. Both terminal and internal alkynes underwent highly regioselective cycloaddition reactions under mild conditions, facilitating release of the peptide construct from the resin with intact side...

  13. Double [3,3]-sigmatropic rearrangement in the enzymatic dioxygenation of benzyl azide: preparation of novel synthetically valuable azido-diols.

    Science.gov (United States)

    Thevenet, Natalia; de la Sovera, Victoria; Vila, María Agustina; Veiga, Nicolás; Gonzalez, David; Seoane, Gustavo; Carrera, Ignacio

    2015-02-06

    Enzymatic dioxygenation of benzyl azide by toluene dioxygenase produces the expected enantiopure cis-cyclohexadienediol along with an exocyclic diene formed by a spontaneous sequence of two [3,3] sigmatropic shifts. This novel dienediol presents high synthetic potential for natural product synthesis. The sigmatropic rearrangements can be reversed by protection of the diol moiety. An optimized production protocol for either of these valuable diols is presented.

  14. Synthesis and post-synthetic modification of amine-, alkyne-, azide- and nitro-functionalized metal-organic frameworks based on DUT-5.

    Science.gov (United States)

    Gotthardt, Meike A; Grosjean, Sylvain; Brunner, Tobias S; Kotzel, Johannes; Gänzler, Andreas M; Wolf, Silke; Bräse, Stefan; Kleist, Wolfgang

    2015-10-14

    Functionalized 4,4'-biphenyldicarboxylic acid molecules with additional amine, alkyne, azide or nitro groups were prepared and applied in the synthesis of novel metal-organic frameworks and mixed-linker metal-organic frameworks isoreticular to DUT-5. The properties of the frameworks could be tuned by varying the number of functional groups in the materials and the amine groups were employed in post-synthetic modification reactions without changing the framework structure or significantly decreasing the porosity of the materials.

  15. Well-defined polyethylene-based graft terpolymers by combining nitroxide-mediated radical polymerization, polyhomologation and azide/alkyne “click” chemistry†

    KAUST Repository

    Alkayal, Nazeeha

    2016-03-30

    Novel well–defined polyethylene–based graft terpolymers were synthesized via the “grafting onto” strategy by combining nitroxide-mediated radical polymerization (NMP), polyhomologation and copper (I)-catalyzed azide-alkyne cycloaddition (CuAAC) “click” chemistry. Three steps were involved in this approach: (i) synthesis of alkyne-terminated polyethylene-b-poly(ε-caprolactone) (PE-b-PCL-alkyne) block copolymers (branches) by esterification of PE-b-PCL-OH with 4-pentynoic acid; the PE-b-PCL-OH was obtained by polyhomologation of dimethylsulfoxonium methylide to afford PE-OH, followed by ring opening polymerization of ε-caprolactone using the PE-OH as macroinitiator, (ii) synthesis of random copolymers of styrene (St) and 4-chloromethylstyrene (4-CMS) with various CMS contents, by nitroxide-mediated radical copolymerization (NMP), and conversion of chloride to azide groups by reaction with sodium azide (NaN3) (backbone) and (iii) “click” linking reaction to afford the PE-based graft terpolymers. All intermediates and final products were characterized by high-temperature size exclusion chromatography (HT-SEC), Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (1H NMR) and differential scanning calorimetry (DSC).

  16. Lead Toxicity

    Science.gov (United States)

    ... blue-gray metal that is mined from the earth’s crust. • Lead has been used for many industrial ... including the kidneys, heart, and reproductive system, • Pregnant women should know that the developing fetus is very ...

  17. Lead Poisoning

    Science.gov (United States)

    ... has also been associated with juvenile delinquency and criminal behavior. In adults, lead can increase blood pressure ... and-forth manner, but rather from left to right (or vise-versa), or from the top of ...

  18. Lead Test

    Science.gov (United States)

    ... poison you. Most lead is present as an inorganic compound and does not move well through the ... D. R., Editors (© 2006). Contemporary Practice in Clinical Chemistry: AACC Press, Washington, DC. Pp 474. Wu, A. (© ...

  19. Inorganic–organic hybrid materials through post-synthesis modification: Impact of the treatment with azides on the mesopore structure

    Directory of Open Access Journals (Sweden)

    Miriam Keppeler

    2011-08-01

    Full Text Available Hybrid, hierarchically organized, monolithic silica gels, comprising periodically arranged mesopores and a cellular macroscopic network, have been prepared through a co-condensation reaction of tetrakis(2-hydroxyethylorthosilicate with chloromethyl-trimethoxysilane or 3-(chloropropyl-triethoxysilane. Subsequent conversion of the chloro groups into azido groups, by nucleophilic substitution with NaN3 in N,N-dimethylformamide, was conducted upon preservation of the monolithic structure. However, treatment with NaN3 had a strong influence on the structure in the mesoporous regime, with changes such as an increase of mesopore diameter, pore volume and lattice constants, as well as a concomitant decrease of the pore wall thickness, as confirmed by small angle X-ray scattering, transmission electron microscopy, and nitrogen sorption analysis. Similar effects were observed for unmodified silica gels by simple ageing in azide-containing media, whether a relatively small or a sterically demanding counter ion (Na+ or (H3C4N+ was used. The structural modification did not seem to depend greatly on whether an organic aprotic solvent (N,N-dimethylformamide, 1,1,3,3-tetramethylurea, 1,3-dimethyl-2-imidazolidinone or a protic solvent that can form hydrogen bonds, such as water, was used.

  20. Chelator-accelerated one-pot 'click' labeling of small molecule tracers with 2-[¹⁸F]fluoroethyl azide.

    Science.gov (United States)

    Galante, Eva; Schoultz, Bent Wilhelm; Koepp, Matthias; Arstad, Erik

    2013-05-10

    2-[¹⁸F]Fluoroethyl azide ([¹⁸F]FEA) can readily be obtained by nucleophilic substitution of 2-azidoethyl-4-toluenesulfonate with [¹⁸F]fluoride (half-life 110 min), and has become widely used as a reagent for 'click' labeling of PET tracers. However, distillation of [18F]FEA is typically required, which is time-consuming and unpractical for routine applications. In addition, copper(I)-catalyzed cycloaddition of [¹⁸F]FEA with non-activated alkynes, and with substrates containing labile functional groups, can be challenging. Herein, we report a highly efficient and practical ligand-accelerated one-pot/two-step method for 'click' labeling of small molecule tracers with [¹⁸F]FEA. The method exploits the ability of the copper(I) ligand bathophenanthrolinedisulfonate to accelerate the rate of the cycloaddition reaction. As a result, alkynes can be added directly to the crude reaction mixture containing [¹⁸F]FEA, and as cyclisation occurs almost immediately at room temperature, the reaction is tolerant to labile functional groups. The method was demonstrated by reacting [¹⁸F]FEA with a series of alkyne-functionalized 6-halopurines to give the corresponding triazoles in 55-76% analytical radiochemical yield.

  1. Sensitivity to friction for primary explosives.

    Science.gov (United States)

    Matyáš, Robert; Šelešovský, Jakub; Musil, Tomáš

    2012-04-30

    The sensitivity to friction for a selection of primary explosives has been studied using a small BAM friction apparatus. The probit analysis was used for the construction of a sensitivity curve for each primary explosive tested. Two groups of primary explosives were chosen for measurement (a) the most commonly used industrially produced primary explosives (e.g. lead azide, tetrazene, dinol, lead styphnate) and (b) the most produced improvised primary explosives (e.g. triacetone triperoxide, hexamethylenetriperoxide diamine, mercury fulminate, acetylides of heavy metals). A knowledge of friction sensitivity is very important for determining manipulation safety for primary explosives. All the primary explosives tested were carefully characterised (synthesis procedure, shape and size of crystals). The sensitivity curves obtained represent a unique set of data, which cannot be found anywhere else in the available literature. Copyright © 2012 Elsevier B.V. All rights reserved.

  2. Ecotoxicology: Lead

    Science.gov (United States)

    Scheuhammer, A.M.; Beyer, W.N.; Schmitt, C.J.; Jorgensen, Sven Erik; Fath, Brian D.

    2008-01-01

    Lead (Pb) is a naturally occurring metallic element; trace concentrations are found in all environmental media and in all living things. However, certain human activities, especially base metal mining and smelting; combustion of leaded gasoline; the use of Pb in hunting, target shooting, and recreational angling; the use of Pb-based paints; and the uncontrolled disposal of Pb-containing products such as old vehicle batteries and electronic devices have resulted in increased environmental levels of Pb, and have created risks for Pb exposure and toxicity in invertebrates, fish, and wildlife in some ecosystems.

  3. Leading men

    DEFF Research Database (Denmark)

    Bekker-Nielsen, Tønnes

    2016-01-01

    Through a systematic comparison of c. 50 careers leading to the koinarchate or high priesthood of Asia, Bithynia, Galatia, Lycia, Macedonia and coastal Pontus, as described in funeral or honorary inscriptions of individual koinarchs, it is possible to identify common denominators but also disting...

  4. Single-Step Synthesis of Small, Azide-Functionalized Gold Nanoparticles: Versatile, Water-Dispersible Reagents for Click Chemistry.

    Science.gov (United States)

    Elliott, Edward W; Ginzburg, Aurora L; Kennedy, Zachary C; Feng, Zhenshuo; Hutchison, James E

    2017-06-13

    Nanoparticles possessing functional groups that can be readily conjugated (e.g., through click chemistry) are important precursors for the preparation of customized nanohybrid products. Such nanoparticles, if they are stable against agglomeration, are easily dispersible and have well-defined surface chemistry and size. As click-ready reagents, they can be stored until their time of use and then simply dispersed and reacted with an appropriate substrate. Gold nanoparticles (AuNPs) are excellent candidates for this purpose, and some clickable gold nanoparticles have been developed; however, AuNPs for use in aqueous systems are often prepared through difficult multistep processes and/or can be poorly dispersible in water. Here we report a single-step synthesis of clickable, water-dispersible AuNPs. The synthesis yields uniform, 3.5 nm diameter cores coated with a well-defined molecular ligand shell that makes the AuNPs stable and dispersible in water. The AuNP mixed ligand shell consists of hydroxyl-terminated ethylene glycol-based ligands to promote dispersion in water and a small number of azide-terminated ligands that readily undergo click reactions with alkynes. The use of a mesofluidic reactor affords fine control over the core size and ligand shell composition and ensures reproducible results (e.g., less than 0.1 nm variation in core diameter between batches). The purified reagents were successfully coupled to a variety of alkyne-containing substrates using both Cu-catalyzed and strain-promoted click reactions. Particle size, morphology, stability, and surface composition were thoroughly characterized using small-angle X-ray scattering, transmission electron microscopy, X-ray photoelectron spectroscopy, UV-vis, and 1 H NMR before and after the click reactions. Both the parent nanoparticles and their click chemistry products are stable during storage and remained dispersible for over a year in water, suggesting their potential for environmental, biological, and

  5. Gas Phase Molecular Spectroscopy: Electronic Spectroscopy of Combustion Intermediates, Chlorine Azide kinetics, and Rovibrational Energy Transfer in Acetylene

    Science.gov (United States)

    Freel, Keith A.

    This dissertation is composed of three sections. The first deals with the electronic spectroscopy of combustion intermediates that are related to the formation of polycyclic aromatic hydrocarbons. Absorption spectra for phenyl, phenoxy, benzyl, and phenyl peroxy radicals were recorded using the technique of cavity ring-down spectroscopy. When possible, molecular constants, vibrational frequencies, and excited state lifetimes for these radicals were derived from these data. The results were supported by theoretical predictions. The second section presents a study of electron attachment to chlorine azide (ClN3) using a flowing-afterglow Langmuir-probe apparatus. Electron attachment rates were measured to be 3.5x10-8 and 4.5x10-8 cm3s-1 at 298 and 400 K respectively. The reactions of ClN3 with eighteen cations and seventeen anions were characterized. Rate constants were measured using a selected ion flow tube. The ionization energy (>9.6eV), proton affinity (713+/-41 kJ mol-1), and electron affinity (2.48+/-0.2 eV) for ClN 3 were determined from these data. The third section demonstrates the use of double resonance spectroscopy to observe state-selected rovibrational energy transfer from the first overtone asymmetric stretch of acetylene. The total population removal rate constants from various rotational levels of the (1,0,1,00,00) vibrational state were determined to be in the range of (9-17) x 10 -10 cm3s-1. Rotational energy transfer accounted for approximately 90% of the total removal rate from each state. Therefore, the upper limit of vibrational energy transfer from the (1,0,1,0 0,00) state was 10%.

  6. Who Leads China's Leading Universities?

    Science.gov (United States)

    Huang, Futao

    2017-01-01

    This study attempts to identify the major characteristics of two different groups of institutional leaders in China's leading universities. The study begins with a review of relevant literature and theory. Then, there is a brief introduction to the selection of party secretaries, deputy secretaries, presidents and vice presidents in leading…

  7. Ultrasound-promoted organocatalytic enamine–azide [3 + 2] cycloaddition reactions for the synthesis of ((arylselanylphenyl-1H-1,2,3-triazol-4-ylketones

    Directory of Open Access Journals (Sweden)

    Gabriel P. Costa

    2017-04-01

    Full Text Available The use of sonochemistry is described in the organocatalytic enamine–azide [3 + 2] cycloaddition between 1,3-diketones and aryl azidophenyl selenides. These sonochemically promoted reactions were found to be amenable to a range of 1,3-diketones or aryl azidophenyl selenides, providing an efficient access to new ((arylselanylphenyl-1H-1,2,3-triazol-4-ylketones in good to excellent yields and short reaction times. In addition, this protocol was extended to β-keto esters, β-keto amides and α-cyano ketones. Selanyltriazoyl carboxylates, carboxamides and carbonitriles were synthesized in high yields at short times of reaction under very mild reaction conditions.

  8. Azide-enolate 1,3-dipolar cycloaddition in the synthesis of novel triazole-based miconazole analogues as promising antifungal agents.

    Science.gov (United States)

    González-Calderón, Davir; Mejía-Dionicio, María G; Morales-Reza, Marco A; Ramírez-Villalva, Alejandra; Morales-Rodríguez, Macario; Jauregui-Rodríguez, Bertha; Díaz-Torres, Eduardo; González-Romero, Carlos; Fuentes-Benítes, Aydeé

    2016-04-13

    Seven miconazole analogs involving 1,4,5-tri and 1,5-disubstituted triazole moieties were synthesized by azide-enolate 1,3-dipolar cycloaddition. The antifungal activity of these compounds was evaluated in vitro against four filamentous fungi, including Aspergillus fumigatus, Trichosporon cutaneum, Rhizopus oryzae, and Mucor hiemalis as well as three species of Candida spp. as yeast specimens. These pre-clinical studies suggest that compounds 4b, 4d and 7b can be considered as drug candidates for future complementary biological studies due to their good/excellent antifungal activities. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  9. The orbital ground state of the azide-substrate complex of human heme oxygenase is an indicator of distal H-bonding: Implications for the enzyme mechanism‡

    OpenAIRE

    Ogura, Hiroshi; Evans, John P.; Peng, Dungeng; Satterlee, James D.; de Montellano, Paul R. Ortiz; Mar, Gerd N. La

    2009-01-01

    The active site electronic structure of the azide complex of substrate-bound human heme oxygenase-1, (hHO) has been investigated by 1H NMR spectroscopy to shed light on the orbital/spin ground state as an indicator of the unique distal pocket environment of the enzyme. 2D 1H NMR assignments of the substrate and substrate-contact residue signals reveal a pattern of substrate methyl contact shifts, that places the lone iron π-spin in the dxz orbital, rather than the dyz orbital found in the cya...

  10. Mechanochemical Iridium(III)-Catalyzed C-H Bond Amidation of Benzamides with Sulfonyl Azides under Solvent-Free Conditions in a Ball Mill.

    Science.gov (United States)

    Hermann, Gary N; Becker, Peter; Bolm, Carsten

    2016-03-07

    Mechanochemical conditions have been applied to an iridium(III)-catalyzed C-H bond amidation process for the first time. In the absence of solvent, the mechanochemical activation enables the formation of an iridium species that catalyzes the ortho-selective amidation of benzamides with sulfonyl azides as the nitrogen source. As the reaction proceeds in the absence of organic solvents without external heating and yields the desired products in excellent yields within short reaction times, this method constitutes a powerful, fast, and environmentally benign alternative to the common solvent-based standard approaches. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Cu/Pd-Catalyzed, Three-Component Click Reaction of Azide, Alkyne, and Aryl Halide: One-Pot Strategy toward Trisubstituted Triazoles.

    Science.gov (United States)

    Wei, Fang; Li, Haoyu; Song, Chuanling; Ma, Yudao; Zhou, Ling; Tung, Chen-Ho; Xu, Zhenghu

    2015-06-05

    A Cu/Pd-catalyzed, three-component click reaction of azide, alkyne, and aryl halide has been developed. By using this Cu/Pd transmetalation relay catalysis, a variety of 1,4,5-trisubstituted 1,2,3-triazoles were quickly assembled in one step in high yields with complete regioselectivity, just like assembling Lego bricks. Notably, different from the well-established CuAAC click reactions only working on terminal alkynes, this reaction offers an alternative solution for the problem of the click reaction of internal alkynes.

  12. Effects of metal chelator, sodium azide, and superoxide dismutase on the oxidative stability in riboflavin-photosensitized oil-in-water emulsion systems.

    Science.gov (United States)

    Lee, JaeHwan; Decker, Eric A

    2011-06-08

    The effects of riboflavin photosensitization on the oxidative stability of oil-in-water (O/W) emulsions were determined using lipid hydroperoxides and headspace volatile analyses. The influences of a metal chelator, sodium azide, and superoxide dismutase (SOD) on oxidation pathways were tested to gain a better understanding of the role of transition metals, singlet oxygen, and superoxide anion, respectively. Emulsions with riboflavin and visible light irradiation had significantly higher lipid hydroperoxides and volatiles (p activity of metals through their ability to produce lipid hydroperoxides and superoxide anion.

  13. Heterogeneous catalysis for azide-alkyne bioconjugation in solution via spin column: Attachment of dyes and saccharides to peptides and DNA.

    Science.gov (United States)

    Kallick, Jeremy; Harris, Sarah; Udit, Andrew K; Hill, Michael G

    2015-12-01

    Copper-catalyzed azide-alkyne cycloaddition (CuAAC) "click" chemistry is widely used and has demonstrated particular utility for bio-orthogonal conjugation reactions. Here we describe a one-pot, heterogeneous bioconjugation and purification method for selectively activated CuAAC. A Cu(II) precursor, with either the neutral ligand 1,10-phenanthroline-5,6-dione or the anionic ligand 4,7-diphenyl-1,10-phenanthroline-disulfonic acid, is converted to the active Cu(I) species within an ion-exchange matrix using zinc amalgam as the reducing agent. The Cu(I) complexes are then layered on top of a size-exclusion matrix within a commercial microcentrifuge spin column; passing a mixture of an ethynyl-labeled biomolecule and an azide-bearing ligand through the column results in clean and efficient coupling. The methodology is demonstrated by glycosylating a DNA oligonucleotide as well as by labeling a membrane-penetrating peptide (octa-arginine) with a coumarin dye.

  14. Site-Specific 64Cu Labeling of the Serine Protease, Active Site Inhibited Factor Seven Azide (FVIIai-N3), Using Copper Free Click Chemistry.

    Science.gov (United States)

    Jeppesen, Troels E; Kristensen, Lotte K; Nielsen, Carsten H; Petersen, Lars C; Kristensen, Jesper B; Behrens, Carsten; Madsen, Jacob; Kjaer, Andreas

    2018-01-17

    A method for site-specific radiolabeling of the serine protease active site inhibited factor seven (FVIIai) with 64Cu has been applied using a biorthogonal click reaction. FVIIai binds to tissue factor (TF), a trans-membrane protein involved in hemostasis, angiogenesis, proliferation, cell migration, and survival of cancer cells. First a single azide moiety was introduced in the active site of this 50 kDa protease. Then a NOTA moiety was introduced via a strain promoted azide-alkyne reaction and the corresponding conjugate was labeled with 64Cu. Binding to TF and the stability was evaluated in vitro. TF targeting capability of the radiolabeled conjugate was tested in vivo by positron emission tomography (PET) imaging in pancreatic human xenograft cancer mouse models with various TF expressions. The conjugate showed good stability (>91% at 16 h), an immunoreactivity of 93.5%, and a mean tumor uptake of 2.1 ± 0.2%ID/g at 15 h post injection. In conclusion, FVIIai was radiolabeled with 64Cu in single well-defined position of the protein. This method can be utilized to prepare conjugates from serine proteases with the label at a specific position.

  15. Electron-transporting layer doped with cesium azide for high-performance phosphorescent and tandem white organic light-emitting devices

    Science.gov (United States)

    Yu, Yaoyao; Chen, Xingming; Jin, Yu; Wu, Zhijun; Yu, Ye; Lin, Wenyan; Yang, Huishan

    2017-07-01

    Cesium azide was employed as an effective n-dopant in the electron-transporting layer (ETL) of organic light-emitting devices (OLEDs) owing to its low deposition temperature and high ambient stability. By doping cesium azide onto 4,7-diphenyl-1,10-phenanthroline, a green phosphorescent OLED having best efficiencies of 66.25 cd A-1, 81.22 lm W-1 and 18.82% was realized. Moreover, the efficiency roll-off from 1000 cd m-2 to 10 000 cd m-2 is only 12.9%, which is comparable with or even lower than that of devices utilizing the co-host system. Physical mechanisms for the improvement of device performance were studied in depth by analyzing the current density-voltage (J-V) characteristics of the electron-only devices. In particular, by comparing the J-V characteristics of the electron-only devices instead of applying the complicated ultraviolet photoelectron spectrometer measurements, we deduced the decrease in barrier height for electron injection at the ETL/cathode contact. Finally, an efficient tandem white OLED utilizing the n-doped layer in the charge generation unit (CGU) was constructed. As far as we know, this is the first report on the application of this CGU for fabricating tandem white OLEDs. The emissions of the tandem device are all in the warm white region from 1213 cd m-2 to 10870 cd m-2, as is beneficial to the lighting application.

  16. A Theoretical Study of the Relationship between the Electrophilicity ω Index and Hammett Constant σp in [3+2] Cycloaddition Reactions of Aryl Azide/Alkyne Derivatives

    Directory of Open Access Journals (Sweden)

    Hicham Ben El Ayouchia

    2016-10-01

    Full Text Available The relationship between the electrophilicity ω index and the Hammett constant σp has been studied for the [2+3] cycloaddition reactions of a series of para-substituted phenyl azides towards para-substituted phenyl alkynes. The electrophilicity ω index—a reactivity density functional theory (DFT descriptor evaluated at the ground state of the molecules—shows a good linear relationship with the Hammett substituent constants σp. The theoretical scale of reactivity correctly explains the electrophilic activation/deactivation effects promoted by electron-withdrawing and electron-releasing substituents in both azide and alkyne components.

  17. Poli (metil azoteto de glicidila - GAP. I: síntese e caracterização Glycidyl azide polymer (GAP. I: syntheses and characterization

    Directory of Open Access Journals (Sweden)

    Sandro P. Ribeiro

    2012-01-01

    Full Text Available O poli (metil azoteto de glicidila - GAP - é um material energético que pode ser utilizado como aglutinante (binder e como plastificante energético em compostos explosivos e propulsores de foguetes. Neste trabalho, foi abordada a síntese do (GAP através da conversão direta da epicloridrina (ECH a GAP. Os reagentes utilizados foram azida de sódio, epicloridrina e vários álcoois extensores de cadeias, o etanodiol, o 1,4-butanodiol, o dietilenoglicol e o glicerol. Alguns parâmetros de operação foram avaliados, como o tempo de reação, a proporção entre os reagentes, dois tipos de solvente e a ordem de adição dos reagentes. A variável observada para a análise foi a massa molecular do GAP. Todos os materiais sintetizados também foram caracterizados por análises de FTIR, UV, RMN, DSC, análise elementar e TGA. Uma maior massa molecular, maior rendimento e uma melhor conversão do grupo azida a GAP foram obtidos com a adição de epicloridrina sobre a azida de sódio e usando DMF como solvente.GAP is an aliphatic polyether that includes hydroxyl groups and highly energetic azide groups. Thus, it is an energetic material that can be used as binder or plasticizing agent in propellants and explosive mixtures. The glycidyl azide polymer (GAP was synthesized and characterized by direct conversion of epichlorohydrin. GAP was synthesized by reaction of sodium azide, epichlorohydrin, and some extensor alcohols. The investigation focused on the effects of some key reaction parameters including reagent proportions, reaction time and two different solvents. The product was characterized by FTIR, UV, NMR, DSC, elemental analysis, TGA and GPC. The species were also evaluated through molecular weight (GPC, glass transition temperature (DSC, ignition time and sensitivity.

  18. [Ru(IV)(F20-TPP)Cl2] efficiently catalysed inter- and intra-molecular nitrene insertion into sp3 C-H bonds of hydrocarbons using phosphoryl azides as nitrene sources.

    Science.gov (United States)

    Xiao, Wenbo; Wei, Jinhu; Zhou, Cong-Ying; Che, Chi-Ming

    2013-05-21

    [Ru(IV)(F20-TPP)Cl2][H2(F20-TPP) = meso-tetrakis(pentafluorophenyl)porphyrin] is an active catalyst for both inter- and intra-molecular nitrene insertion into sp(3) C-H bonds of hydrocarbons in good to high product yields using phosphoryl azides as nitrene sources.

  19. Solvent-resistant small molecule solar cells by roll-to-roll fabrication via introduction of azide cross-linkable group

    DEFF Research Database (Denmark)

    Chen, Mei-Rong; Fan, Cong-Cheng; Andersen, Thomas Rieks

    2014-01-01

    , without dissolving the pre-patterned layers. In order to investigate the photovoltaic performances of the newly synthesized compound, large area solar cells were produced by roll coating technique. Two set of devices were fabricated by employing DPP(BT-N-3)(2) as either an electron donor or acceptor....... A best power conversion efficiency of 0.067%, combined with an open circuit voltage of 0.53 V, and a fill factor of 37.6% were obtained for the device with DPP(BT-N-3)(2) as an electron acceptor. In addition, we could prove that the large area small molecule based organic solar cells could be fabricated......A novel cross-linkable azide-functionalized diketopyrrolopyrrole based compound DPP(BT-N-3)(2) was designed and synthesized via Stille coupling. Cross-linking of such molecule could help us fabricate insoluble film which could be used to fabricate heterostructures through solution processing...

  20. Poli (metil azoteto de glicidila - GAP. II: mecanismo de reação Glycidyl azide polymer (GAP. II: reaction mechanism

    Directory of Open Access Journals (Sweden)

    Sandro P. Ribeiro

    2012-01-01

    Full Text Available O poli (metil azoteto de glicidila - GAP - é um material energético que pode ser utilizado como aglutinante (binder e como plastificante energético em compostos explosivos e propulsores de foguetes. O GAP de baixo peso molecular pode ser obtido pela conversão direta da epicloridrina (ECH a GAP. Neste trabalho, é proposto um possível mecanismo para esta conversão direta, fundamentado em análises de infravermelho de espécies intermediárias.GAP is an energetic material that can be used as binder or plasticizing agent in propellants and explosive mixtures. The glycidyl azide polymer (GAP can be synthesized by direct conversion of epichlorohydrin. Here, a mechanism is proposed for the reaction used, based on an analysis of infrared spectra of intermediate species.

  1. Assessment of the Full Compatibility of Copper(I)-Catalyzed Alkyne-Azide Cycloaddition and Oxime Click Reactions for bis-Labelling of Oligonucleotides.

    Science.gov (United States)

    Estalayo-Adriàn, Sandra; Lartia, Rémy; Meyer, Albert; Vasseur, Jean-Jacques; Morvan, François; Defrancq, Eric

    2015-04-01

    The conjugation of oligonucleotides with reporters is of great interest for improving their intrinsic properties or endowing new ones. In this context, we report herein a new procedure for the bis-labelling of oligonucleotides through oxime ligation (Click-O) and copper(I)-catalyzed alkyne-azide cycloaddition (Click-H). 5'-Azido and 3'-aldehyde precursors were incorporated into oligonucleotides, and subsequent coupling reactions through Click-O and Click-H (or vice versa) were successfully achieved. In particular, we exhaustively investigated the full compatibility of each required step for both tethering strategies. The results demonstrate that click Huisgen and click oxime reactions are fully compatible. However, whilst both approaches can deliver the targeted doubly conjugated oligonucleotide, the route involving click oxime ligation prior to click Huisgen is significantly more successful. Thus the reactions investigated here can be considered to be key elements of the chemical toolbox for the synthesis of highly sophisticated bioconjugates.

  2. Synthesis of 8-(1,2,3-triazol-1-yl)-7-deazapurine nucleosides by azide-alkyne click reactions and direct C-H bond functionalization.

    Science.gov (United States)

    Kavoosi, Sam; Rayala, Ramanjaneyulu; Walsh, Brenna; Barrios, Maria; Gonzalez, Walter G; Miksovska, Jaroslava; Mathivathanan, Logesh; Raptis, Raphael G; Wnuk, Stanislaw F

    2016-09-28

    Treatment of toyocamycin or sangivamycin with 1,3-dibromo-5,5-dimethylhydantoin in MeOH (r.t./30 min) gave 8-bromotoyocamycin and 8-bromosangivamycin in good yields. Nucleophilic aromatic substitution of 8-bromotoyocamycin with sodium azide provided novel 8-azidotoyocamycin. Strain promoted click reactions of the latter with cyclooctynes resulted in the formation of the 1,2,3-triazole products. Iodine-mediated direct C8-H bond functionalization of tubercidin with benzotriazoles in the presence of tert-butyl hydroperoxide gave the corresponding 8-benzotriazolyltubercidin derivatives. The 8-(1,2,3-triazol-1-yl)-7-deazapurine derivatives showed moderate quantum yields and a large Stokes shifts of ~ 100 nm.

  3. Kinetics and mechanics of photo-polymerized triazole-containing thermosetting composites via the copper(I)-catalyzed azide-alkyne cycloaddition.

    Science.gov (United States)

    Song, Han Byul; Wang, Xiance; Patton, James R; Stansbury, Jeffrey W; Bowman, Christopher N

    2017-06-01

    Several features necessary for polymer composite materials in practical applications such as dental restorative materials were investigated in photo-curable CuAAC (copper(I)-catalyzed azide-alkyne cycloaddition) thermosetting resin-based composites with varying filler loadings and compared to a conventional BisGMA/TEGDMA based composite. Tri-functional alkyne and di-functional azide monomers were synthesized for CuAAC resins and incorporated with alkyne-functionalized glass microfillers for CuAAC composites. Polymerization kinetics, in situ temperature change, and shrinkage stress were monitored simultaneously with a tensometer coupled with FTIR spectroscopy and a data-logging thermocouple. The glass transition temperature was analyzed by dynamic mechanical analysis. Flexural modulus/strength and flexural toughness were characterized in three-point bending on a universal testing machine. The photo-CuAAC polymerization of composites containing between 0 and 60wt% microfiller achieved ∼99% conversion with a dramatic reduction in the maximum heat of reaction (∼20°C decrease) for the 60wt% filled CuAAC composites as compared with the unfilled CuAAC resin. CuAAC composites with 60wt% microfiller generated more than twice lower shrinkage stress of 0.43±0.01MPa, equivalent flexural modulus of 6.1±0.7GPa, equivalent flexural strength of 107±9MPa, and more than 10 times higher energy absorption of 10±1MJm -3 when strained to 11% relative to BisGMA-based composites at equivalent filler loadings. Mechanically robust and highly tough, photo-polymerized CuAAC composites with reduced shrinkage stress and a modest reaction exotherm were generated and resulted in essentially complete conversion. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  4. Sensitivity to friction for primary explosives

    Energy Technology Data Exchange (ETDEWEB)

    Matyas, Robert, E-mail: robert.matyas@upce.cz [Institute of Energetic Materials, Faculty of Chemical Technology, University of Pardubice, Pardubice 532 10 (Czech Republic); Selesovsky, Jakub; Musil, Tomas [Institute of Energetic Materials, Faculty of Chemical Technology, University of Pardubice, Pardubice 532 10 (Czech Republic)

    2012-04-30

    Highlights: Black-Right-Pointing-Pointer The friction sensitivity of 14 samples of primary explosives was determined. Black-Right-Pointing-Pointer The same apparatus (small scale BAM) and the same method (probit analysis) was used. Black-Right-Pointing-Pointer The crystal shapes and sizes were documented with microscopy. Black-Right-Pointing-Pointer Almost all samples are less sensitive than lead azide, which is commercially used. Black-Right-Pointing-Pointer The organic peroxides (TATP, DADP, HMTD) are not as sensitive as often reported. - Abstract: The sensitivity to friction for a selection of primary explosives has been studied using a small BAM friction apparatus. The probit analysis was used for the construction of a sensitivity curve for each primary explosive tested. Two groups of primary explosives were chosen for measurement (a) the most commonly used industrially produced primary explosives (e.g. lead azide, tetrazene, dinol, lead styphnate) and (b) the most produced improvised primary explosives (e.g. triacetone triperoxide, hexamethylenetriperoxide diamine, mercury fulminate, acetylides of heavy metals). A knowledge of friction sensitivity is very important for determining manipulation safety for primary explosives. All the primary explosives tested were carefully characterised (synthesis procedure, shape and size of crystals). The sensitivity curves obtained represent a unique set of data, which cannot be found anywhere else in the available literature.

  5. ECG monitoring leads and special leads.

    Science.gov (United States)

    Francis, Johnson

    ECG monitoring is common place in the hospital and even pre-hospital setting. The need for different types of lead systems in different settings has been emphasised. Simple three electrode bipolar recording is ubiquitous for monitoring. This can be used to record modified bipolar chest leads as well. Using five leads gives the option of getting a chest lead in addition to bipolar limb leads, enhancing detection of ischemia during procedures. Lead stability is important when the movement of the subject is maximum as in exercise testing. Mason-Likar modification with limb leads shifted to the torso is popular for exercise testing, though the diagnostic value of the ECG is altered. Lund system with leads on proximal part of limbs have both stability and fair diagnostic value. EASI lead system permits derivation of 12 leads from just five electrodes. Lewis lead and the newly devised modified limb lead system are useful in enhancing detection of atrial activity. Fontaine lead has been designed to improve visualization of Epsilon wave in arrhythmogenic right ventricular dysplasia. Copyright © 2016 Indian Heart Rhythm Society. Production and hosting by Elsevier B.V. All rights reserved.

  6. Regioselective Sequential Modification of Chitosan via Azide-Alkyne Click Reaction: Synthesis, Characterization, and Antimicrobial Activity of Chitosan Derivatives and Nanoparticles

    Science.gov (United States)

    Sarwar, Atif; Katas, Haliza; Samsudin, Siti Noradila; Zin, Noraziah Mohamad

    2015-01-01

    Recently, the attention of researchers has been drawn toward the synthesis of chitosan derivatives and their nanoparticles with enhanced antimicrobial activities. In this study, chitosan derivatives with different azides and alkyne groups were synthesized using click chemistry, and these were further transformed into nanoparticles by using the ionotropic gelation method. A series of chitosan derivatives was successfully synthesized by regioselective modification of chitosan via an azide-alkyne click reaction. The amino moieties of chitosan were protected during derivatization by pthaloylation and subsequently unblocked at the end to restore their functionality. Nanoparticles of synthesized derivatives were fabricated by ionic gelation to form complexes of polyanionic penta-sodium tripolyphosphate (TPP) and cationic chitosan derivatives. Particle size analysis showed that nanoparticle size ranged from 181.03 ± 12.73 nm to 236.50 ± 14.32 nm and had narrow polydispersity index and positive surface charge. The derivatives and corresponding nanoparticles were evaluated in vitro for antibacterial and antifungal activities against three gram-positive and gram-negative bacteria and three fungal strains, respectively. The minimum inhibitory concentration (MIC) of all derivatives ranged from 31.3 to 250 µg/mL for bacteria and 188 to1500 µg/mL for fungi and was lower than that of native chitosan. The nanoparticles with MIC ranging from 1.56 to 25 µg/mLfor bacteria and 94 to 750 µg/mL for fungi exhibited higher activity than the chitosan derivatives. Chitosan O-(1-methylbenzene) triazolyl carbamate and chitosan O-(1-methyl phenyl sulfide) triazolyl carbamate were the most active against the tested bacterial and fungal strains. The hemolytic assay on erythrocytes and cell viability test on two different cell lines (Chinese hamster lung fibroblast cells V79 and Human hepatic cell line WRL68) demonstrated the safety; suggesting that these derivatives could be used in future

  7. Regioselective Sequential Modification of Chitosan via Azide-Alkyne Click Reaction: Synthesis, Characterization, and Antimicrobial Activity of Chitosan Derivatives and Nanoparticles.

    Directory of Open Access Journals (Sweden)

    Atif Sarwar

    Full Text Available Recently, the attention of researchers has been drawn toward the synthesis of chitosan derivatives and their nanoparticles with enhanced antimicrobial activities. In this study, chitosan derivatives with different azides and alkyne groups were synthesized using click chemistry, and these were further transformed into nanoparticles by using the ionotropic gelation method. A series of chitosan derivatives was successfully synthesized by regioselective modification of chitosan via an azide-alkyne click reaction. The amino moieties of chitosan were protected during derivatization by pthaloylation and subsequently unblocked at the end to restore their functionality. Nanoparticles of synthesized derivatives were fabricated by ionic gelation to form complexes of polyanionic penta-sodium tripolyphosphate (TPP and cationic chitosan derivatives. Particle size analysis showed that nanoparticle size ranged from 181.03 ± 12.73 nm to 236.50 ± 14.32 nm and had narrow polydispersity index and positive surface charge. The derivatives and corresponding nanoparticles were evaluated in vitro for antibacterial and antifungal activities against three gram-positive and gram-negative bacteria and three fungal strains, respectively. The minimum inhibitory concentration (MIC of all derivatives ranged from 31.3 to 250 µg/mL for bacteria and 188 to1500 µg/mL for fungi and was lower than that of native chitosan. The nanoparticles with MIC ranging from 1.56 to 25 µg/mLfor bacteria and 94 to 750 µg/mL for fungi exhibited higher activity than the chitosan derivatives. Chitosan O-(1-methylbenzene triazolyl carbamate and chitosan O-(1-methyl phenyl sulfide triazolyl carbamate were the most active against the tested bacterial and fungal strains. The hemolytic assay on erythrocytes and cell viability test on two different cell lines (Chinese hamster lung fibroblast cells V79 and Human hepatic cell line WRL68 demonstrated the safety; suggesting that these derivatives could be

  8. Learn about Lead

    Science.gov (United States)

    ... Protection Agency Search Search Lead Contact Us Share Learn about Lead General Lead Information Read more about ... water, soil, consumer products, food, and occupational settings. Learn more about sources of lead exposure: At home ...

  9. Lead Poisoning Prevention Tips

    Science.gov (United States)

    ... or removed safely. How are children exposed to lead? Lead-based paint and lead contaminated dust are ... What can be done to prevent exposure to lead? It is important to determine the construction year ...

  10. Lead levels - blood

    Science.gov (United States)

    Blood lead levels ... is used to screen people at risk for lead poisoning. This may include industrial workers and children ... also used to measure how well treatment for lead poisoning is working. Lead is common in the ...

  11. Mechanism of cobalt(II) porphyrin-catalyzed C−H amination with organic azides: radical nature and H-atom abstraction ability of the key cobalt(III)-nitrene intermediates

    NARCIS (Netherlands)

    Lyaskovskyy, V.; Olivos Suarez, A.I.; Lu, H.; Jiang, H.; Zhang, X.P.; de Bruin, B.

    2011-01-01

    The mechanism of cobalt(II) porphyrin-catalyzed benzylic C-H bond amination of ethylbenzene, toluene, and 1,2,3,4-tetrahydronaphthalene (tetralin) using a series of different organic azides [N3C(O)OMe, N3SO2Ph, N3C(O)Ph, and N3P(O)(OMe)2] as nitrene sources was studied by means of density functional

  12. Ultrasonically-enhanced preparation, characterization of CaFe-layered double hydroxides with various interlayer halide, azide and oxo anions (CO32-, NO3-, ClO4-).

    Science.gov (United States)

    Szabados, Márton; Varga, Gábor; Kónya, Zoltán; Kukovecz, Ákos; Carlson, Stefan; Sipos, Pál; Pálinkó, István

    2018-01-01

    An ultrasonically-enhanced mechanochemical method was developed to synthesize CaFe-layered double hydroxides (LDHs) with various interlayer anions (CO 3 2- , NO 3 - , ClO 4 - , N 3 - , F - , Cl - , Br - and I - ). The duration of pre-milling and ultrasonic irradiation and the variation of synthesis temperature in the wet chemical step were investigated to obtain the optimal parameters of preparation. The main method to characterize the products was X-ray diffractometry, but infrared and synchrotron-based X-ray absorption spectroscopies as well as thermogravimetric measurements were also used to learn about fine structural details. The synthesis method afforded successful intercalation of the anions, among others the azide anion, a rarely used counter ion providing a system, which enables safe handling the otherwise highly reactive anion. The X-ray absorption spectroscopic measurements revealed that the quality of the interlayered anions could modulate the spatial arrangement of the calcium ions around the iron(III) ions, but only in the second coordination sphere. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Electronic Structure of Manganese Complexes of the Redox-Non-innocent Tetrazene Ligand and Evidence for the Metal-Azide/Imido Cycloaddition Intermediate.

    Science.gov (United States)

    Vaddypally, Shivaiah; McKendry, Ian G; Tomlinson, Warren; Hooper, Joseph P; Zdilla, Michael J

    2016-07-18

    The first synthetic manganese tetrazene complexes are described as a redox pair comprising anionic [Mn(N4 Ad2 )2 ](-) (1) and neutral Mn(N4 Ad2 )2 (2) complexes (N4 Ad2 =[Ad-N-N=N-N-Ad](2-) ). Compound 1 is obtained in two forms as lithium salts, one as a cationic Li2 Mn cluster, and one as a Mn-Li 1D ionic polymer. Compound 1 is electronically described as a Mn(III) center with two [N4 Ad2 ](2-) ligands. The one-electron oxidized 2 is crystalized in two morphologies, one as pure 2 and one as an acetonitrile adduct. Despite similar composition, the behavior of 2 differs in the two morphologies. Compound 2-MeCN is relatively air and temperature stable. Crystalline 2, on the other hand, exhibits a compositional, dynamic disorder wherein the tetrazene metallacycle ring-opens into a metal imide/azide complex detectable by X-ray crystallography and FTIR spectroscopy. Electronic structure of 2 was examined by EPR and XPS spectroscopies and DFT calculations, which indicate 2 is best described as a Mn(III) ion with an anion radical delocalized across the two ligands through spin-polarization effects. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Circular DNA by "Bis-Click" Ligation: Template-Independent Intramolecular Circularization of Oligonucleotides with Terminal Alkynyl Groups Utilizing Bifunctional Azides.

    Science.gov (United States)

    Yang, Haozhe; Seela, Frank

    2016-01-22

    A highly effective and convenient "bis-click" strategy was developed for the template-independent circularization of single-stranded oligonucleotides by employing copper(I)-assisted azide-alkyne cycloaddition. Terminal triple bonds were incorporated at both ends of linear oligonucleotides. Alkynylated 7-deaza-2'-deoxyadenosine and 2'-deoxyuridine residues with different side chains were used in solid-phase synthesis with phosphoramidite chemistry. The bis-click ligation of linear 9- to 36-mer oligonucleotides with 1,4-bis(azidomethyl)benzene afforded circular DNA in a simple and selective way; azido modification of the oligonucleotide was not necessary. Short ethynyl side chains were compatible with the circularization of longer oligonucleotides, whereas octadiynyl residues were used for short 9-mers. Compared with linear duplexes, circular bis-click constructs exhibit a significantly increased duplex stability over their linear counterparts. The intramolecular bis-click ligation protocol is not limited to DNA, but may also be suitable for the construction of other macrocycles, such as circular RNAs, peptides, or polysaccharides. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Phlomis mauritanica extracts reduce the xanthine oxidase activity, scavenge the superoxide anions, and inhibit the aflatoxin B1-, sodium azide-, and 4-nitrophenyldiamine-induced mutagenicity in bacteria.

    Science.gov (United States)

    Limem, Ilef; Bouhlel, Ines; Bouchemi, Meriem; Kilani, Soumaya; Boubaker, Jihed; Ben-Sghaier, Mohamed; Skandrani, Ines; Behouri, Wissem; Neffati, Aicha; Ghedira, Kamel; Chekir-Ghedira, Leila

    2010-06-01

    Four extracts were prepared from the leaves of Phlomis mauritanica: lyophilized infusion, total oligomer flavonoids, methanol, and ethyl acetate extracts. The antimutagenic properties of these extracts were investigated by assessing the inhibition of the mutagenic effects of direct-acting mutagens such as sodium azide and 4-nitrophenylenediamine and indirect-acting mutagens like aflatoxin B1 (AFB1) using the Ames assay. The four extracts prepared from P. mauritanica strongly inhibit the mutagenicity induced by AFB1 in both Salmonella typhimurium TA 100 and TA 98 assay systems. Lyophilized infusion and methanol extracts at the dose of 250 microg per plate reduced AFB1 mutagenicity by 93% and 91%, respectively, in S. typhymurium strain TA 100. We examined also the antioxidant effect of these extracts by the enzymatic xanthine/xanthine oxidase assay. Result indicated that total oligomer flavonoids and ethyl acetate and methanol extracts were potent inhibitors of xanthine oxidase activity. In contrast, lyophilized infusion, total oligomer flavonoids, and methanol extracts exhibited a high degree of superoxide anion scavenging. Our findings emphasize the potential of P. mauritanica extracts to prevent mutations and oxidant effects. Furthermore, the results presented here could be an additional argument to support the use of this species as a medicinal and dietary plant.

  16. Chelator-Accelerated One-Pot ‘Click’ Labeling of Small Molecule Tracers with 2-[18F]Fluoroethyl Azide

    Directory of Open Access Journals (Sweden)

    Erik Årstad

    2013-05-01

    Full Text Available 2-[18F]Fluoroethyl azide ([18F]FEA can readily be obtained by nucleophilic substitution of 2-azidoethyl-4-toluenesulfonate with [18F]fluoride (half-life 110 min, and has become widely used as a reagent for ‘click’ labeling of PET tracers. However, distillation of [18F]FEA is typically required, which is time-consuming and unpractical for routine applications. In addition, copper(I-catalyzed cycloaddition of [18F]FEA with non-activated alkynes, and with substrates containing labile functional groups, can be challenging. Herein, we report a highly efficient and practical ligand-accelerated one-pot/two-step method for ‘click’ labeling of small molecule tracers with [18F]FEA. The method exploits the ability of the copper(I ligand bathophenanthrolinedisulfonate to accelerate the rate of the cycloaddition reaction. As a result, alkynes can be added directly to the crude reaction mixture containing [18F]FEA, and as cyclisation occurs almost immediately at room temperature, the reaction is tolerant to labile functional groups. The method was demonstrated by reacting [18F]FEA with a series of alkyne-functionalized 6-halopurines to give the corresponding triazoles in 55–76% analytical radiochemical yield.

  17. Preparation of Azidated Polybutadiene(Az-PBD)/Ethylene-Vinyl Acetate Copolymer(EVA) Blends for the Application of Energetic Thermoplastic Elastomer

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Sang Won; Choi, Myung Chan; Chang, Young-Wook; Noh, Si-Tae [Hanyang University, Ansan (Korea, Republic of); Kwon, Soon Kil [Agency for Defense Development, Daejeon (Korea, Republic of)

    2015-02-15

    A new energetic thermoplastic elastomer based on the azidated polybutadiene(Az-PBD)/ethylene vinyl acetate copolymer (EVA) blends was prepared, and structure and properties of the blends were investigated by SEM, DSC, DMA, tensile testing and combustion test. The Az-PBD was synthesized via a two-step process involving the addition reaction of commercially available 1,2-PBD with Br{sub 2} and subsequent nucleophilic substitution reaction of the brominated PBD with NaN{sub 3}. EVA/Az-PBD with 90/10, 80/20, 70/30 (wt/wt) was prepared by a solution blending. SEM, DSC, and DMA results revealed that the blends are partially compatible and Az-PBD is dispersed in continuous EVA matrix. Tensile test showed that modulus and tension set increased while elongation-at-break of the blends decreased with increasing Az-PBD content in the blends, but all the blends showed a elongation at break as high as 700% and a tension set of less than 5%, indicating that the blends are typically elastomeric. Combustion test showed that, with increasing Az-PBD content in the blend, higher energy can be released.

  18. Lead and the Romans

    Science.gov (United States)

    Reddy, Aravind; Braun, Charles L.

    2010-01-01

    Lead poisoning has been a problem since early history and continues into modern times. An appealing characteristic of lead is that many lead salts are sweet. In the absence of cane and beet sugars, early Romans used "sugar of lead" (lead acetate) to sweeten desserts, fruits, and sour wine. People most at risk would have been those who…

  19. Lead (Pb) Air Pollution

    Science.gov (United States)

    ... Environmental Protection Agency Search Search Lead (Pb) Air Pollution Contact Us Share As a result of EPA's ... protect aquatic and terrestrial ecosystems. Lead (Pb) Air Pollution Basic Information How does lead get in the ...

  20. Cryogenic current leads

    Energy Technology Data Exchange (ETDEWEB)

    Zizek, F.

    1982-01-01

    Theoretical, technical and design questions are examined of cryogenic current leads for SP of magnetic systems. Simplified mathematical models are presented for the current leads. To illustrate modeling, the calculation is made of the real current leads for 500 A and three variants of current leads for 1500 A for the enterprise ''Shkoda.''

  1. Fully recoverable rigid shape memory foam based on copper-catalyzed azide-alkyne cycloaddition (CuAAC) using a salt leaching technique.

    Science.gov (United States)

    Alzahrani, Abeer A; Saed, Mohand; Yakacki, Christopher M; Song, Han Byul; Sowan, Nancy; Walston, Joshua J; Shah, Parag K; McBride, Matthew K; Stansbury, Jeffrey W; Bowman, Christopher N

    2018-01-07

    This study is the first to employ the use of the copper-catalyzed azide-alkyne cycloaddition (CuAAC) polymerization to form a tough and stiff, porous material from a well-defined network possessing a high glass transition temperature. The effect of the network linkages formed as a product of the CuAAC reaction, i.e., the triazoles, on the mechanical behavior at high strain was evaluated by comparing the CuAAC foam to an epoxy-amine-based foam, which consisted of monomers with similar backbone structures and mechanical properties (i.e., T g of 115 °C and a rubbery modulus of 1.0 MPa for the CuAAC foam, T g of 125 °C and a rubbery modulus of 1.2 MPa for the epoxy-amine foam). When each foam was compressed uniformly to 80% strain at ambient temperature, the epoxy-amine foam was severely damaged after only reaching 70% strain in the first compression cycle with a toughness of 300 MJ/m 3 . In contrast, the CuAAC foam exhibited pronounced ductile behavior in the glassy state with three times higher toughness of 850 MJ/m 3 after the first cycle of compression to 80% strain. Additionally, when the CuAAC foam was heated above T g after each of five compression cycles to 80% strain at ambient temperature, the foam completely recovered its original shape while exhibiting a gradual decrease in mechanical performance over the multiple compression cycles. The foam demonstrated almost complete shape fixity and recovery ratios even through five successive cycles, indicative of "reversible plasticity", making it highly desirable as a glassy shape memory foams.

  2. Effect of vitamin E and selenium separately and in combination on biochemical, immunological and histological changes induced by sodium azide in male mice.

    Science.gov (United States)

    El-Shenawy, Nahla S; AL-Harbi, Mohammad S; Hamza, Reham Z

    2015-01-01

    Sodium azide (SA) is used as an active ingredient to control a broad spectrum of soil borne pathogens including insects, weeds, nematodes, fungi, and bacteria. The purpose of this study was to evaluate the ameliorator property of vitamin E (Vit E) or/and selenium (Se) against SA-induced injury in male mice at the biochemical, immunological and histological levels. The mice were divided into nine groups (10/group). The first three groups were served as control, Vit E and Se while, the second three groups were treated with three different doses of SA. The last three groups were treated with high dose of SA with Vit E or Se or Vit E and Se and all animals were treated for a period of 30 days. Exposure to SA at the three doses to mice led to an alternation of liver and kidney functions, decrease the testosterone concentration, decreased IgG and IgM levels as well as the increasing the TNF-α. The effects of SA on the biochemical parameters of mice were dose-dependent. Administration of Se or/and Vit E to SA-treated mice attenuates the toxicity of this compound, objectified by biochemical and histological improvement of liver, kidney and testis. But, the alleviation is more pronounced with the both antioxidants. Thus, the synergistic effect of Se and Vit E is most powerful in reducing the toxicity induced by SA and improving the humoral immune response of mice. Copyright © 2014 Elsevier GmbH. All rights reserved.

  3. Lead content of foodstuffs.

    Science.gov (United States)

    Mitchell, D G; Aldous, K M

    1974-05-01

    The lead content of a number of foodstuffs, particularly baby fruit juices and milk, is reported. Samples were analyzed in quadruplicate by using an automated Delves cup atomic absorption procedure. A large proportion of the products examined contained significant amounts of lead. Of 256 metal can examined, the contents of 62% contained a lead level of 100 mug/l. or more, 37% contained 200 mug/l. or more and 12% contained 400 mug/l. lead or more. Of products in glass and aluminum containers, only 1% had lead levels in excess of 200 mug/l. Lead levels of contents also correlate with the seam length/volume ratio of the leaded seam can. A survey of bulk milk showed a mean lead level of 40 mug/l. for 270 samples; for canned evaporated milk the mean level was 202 mug/l. These data indicate a potential health hazard.

  4. Lead and tap water

    Science.gov (United States)

    Water contaminated with lead ... The Environmental Protection Agency (EPA) monitors drinking water in the United States. It requires water suppliers to produce annual water quality reports. These reports include information about lead amounts, and they ...

  5. NA49: lead-lead collision

    CERN Multimedia

    1996-01-01

    This is an image of an actual lead ion collision taken from tracking detectors on the NA49 experiment, part of the heavy ion project at CERN. These collisions produce a very complicated array of hadrons as the heavy ions break up. It is hoped that one of these collisions will eventually create a new state of matter known as quark-gluon plasma.

  6. Lead Poisoning (For Parents)

    Science.gov (United States)

    ... Needs a Kidney Transplant Vision Facts and Myths Lead Poisoning KidsHealth > For Parents > Lead Poisoning Print A ... Family en español La intoxicación por plomo About Lead Poisoning If you have young kids, it's important ...

  7. Lead Poisoning in Childhood.

    Science.gov (United States)

    Pueschel, Siegfried M., Ed.; Linakis, James G., Ed.; Anderson, Angela C., Ed.

    The magnitude of childhood lead poisoning has been inexplicably neglected by modern medicine and by legislators. However, since the 1970s, increased attention has been focused on lead poisoning, and advances have been made in several areas, including understanding of the neurodevelopmental and behavioral ramifications of lead poisoning, and…

  8. Lead poisoning: An overview

    Science.gov (United States)

    Gendel, Neil

    1993-01-01

    A problem that should be of great concern to all of us is the lead poisoning of children. First, I would like to present a short overview concerning the reasons everyone should care about lead poisoning, then discuss the history of lead poisoning, what is happening today across the country, and the future.

  9. Lead Poisoning in Children.

    Science.gov (United States)

    Drummond, A. H., Jr.

    1981-01-01

    Early symptoms of lead poisoning in children are often overlooked. Lead poisoning has its greatest effects on the brain and nervous system. The obvious long-term solution to the lead poisoning problem is removal of harmful forms of the metal from the environment. (JN)

  10. Synthesis of 6-amino-5-cyano-1,4-disubstituted-2(1H)-pyrimidinones via copper-(I)-catalyzed alkyne-azide 'click chemistry' and their reactivity.

    Science.gov (United States)

    Najahi, Ennaji; Sudor, Jan; Chabchoub, Fakher; Nepveu, Françoise; Zribi, Fethi; Duval, Romain

    2010-12-03

    In this paper we present the room temperature synthesis of a novel serie of 1,4-disubstituted-1,2,3-triazoles 4a-l by employing the (3+2) cycloaddition reaction of pyrimidinones containing alkyne functions with different model azides in the presence of copper sulphate and sodium ascorbate. To obtain the final triazoles, we also synthesized the major precursors 6-amino-5-cyano-1,4-disubstituted-2(1H)-pyrimidinones 3a-r from ethyl 2,2-dicyanovinylcarbamate derivatives 2a-c and various primary aromatic amines containing an alkyne group. The triazoles were prepared in good to very good yields.

  11. L-Proline catalyzed one-step synthesis of 4,5-diaryl-2H-1,2,3-triazoles from heteroaryl cyanostilbenes via [3+2] cycloaddition of azide.

    Science.gov (United States)

    Penthala, Narsimha Reddy; Madadi, Nikhil Reddy; Janganati, Venumadhav; Crooks, Peter A

    2014-10-01

    Use of a novel reagent has been established for the synthesis of a series of 4,5-diaryl-2H-1,2,3-triazoles (6a-i and 9a-e) from cyanostilbene analogs of benzo[b]thiophene, benzo[b]furan and indole, catalyzed by L-proline via Lewis base-catalyzed one-step [3+2]cycloaddition of azide. This method provides an efficient, simple and environmentally benign procedure that affords good yields and relatively short reaction times.

  12. Arene ruthenium(II) azido complexes incorporating N intersection O chelate ligands: Synthesis, spectral studies and 1,3-dipolar-cycloaddition to a coordinated azide in ruthenium(II) compounds

    Digital Repository Service at National Institute of Oceanography (India)

    Singh, K.S.; Kaminsky, W.

    (Arrora Matthey), L-proline, glycine, dimethylacetylene dicarboxylate (DMD), diethylacetylene 3    dicarboxylate (DED) and sodium azide (Sigma Aldrich), were used as received. NMR spectra were recorded on a Bruker Avance 300 MHz spectrometer at 300.13 (1...)Cl]2 (0.1g, 0.159 mmol) and sodium salt of glycine (0.034 g, 0.351 mmol) in methanol. Yield: 0.076g (68%). Alternative method: This complex was prepared using an alternative method as described for complex 6 using [(p-cymene)Ru(µN3)Cl]2 (0.072g...

  13. Lead encephalopathy in adults

    Directory of Open Access Journals (Sweden)

    Janapareddy Vijaya Bhaskara Rao

    2014-01-01

    Full Text Available Lead poisoning is a common occupational health hazard in developing countries. We report the varied clinical presentation, diagnostic and management issues in two adult patients with lead encephalopathy. Both patients worked in a battery manufacturing unit. Both patients presented with seizures and one patient also complained of abdominal colic and vomiting. Both were anemic and a lead line was present. Blood lead level in both the patients was greater than 25 µg/dl. Magnetic resonance imaging of brain revealed bilateral symmetric involvement of the thalamus, lentiform nucleus in both patients and also the external capsules, sub-cortical white matter in one patient. All these changes, seen as hyperintensities in T2-weighted images suggested demyelination. They were advised avoidance of further exposure to lead and were treated with anti-epileptics; one patient also received D-penicillamine. They improved well on follow-up. Lead encephalopathy is an uncommon but important manifestation of lead toxicity in adults.

  14. Lead in the environment

    Science.gov (United States)

    Pattee, Oliver H.; Pain, Deborah J.; Hoffman, David J.; Rattner, Barnett A.; Burton, G. Allen; Cairns, John

    2003-01-01

    Anthropogenic uses of lead have probably altered its availability and environmental distribution more than any other toxic element. Consequently, lead concentrations in many living organisms may be approaching thresholds of toxicity for the adverse effects of lead. Such thresholds are difficult to define, as they vary with the chemical and physical form of lead, exposure regime, other elements present and also vary both within and between species. The technological capability to accurately quantify low lead concentrations has increased over the last decade, and physiological and behavioral effects have been measured in wildlife with tissue lead concentrations below those previously considered safe for humans.s.236 Consequently. lead criteria for the protection of wildlife and human health are frequently under review, and 'thresholds' of lead toxicity are being reconsidered. Proposed lead criteria for the protection of natural resources have been reviewed by Eisler. Uptake of lead by plants is limited by its generally low availability in soils and sediments, and toxicity may be limited by storage mechanisms and its apparently limited translocation within most plants. Lead does not generally accumulate within the foliar parts of plants, which limits its transfer to higher trophic levels. Although lead may concentrate in plant and animal tissues, no evidence of biomagnification exists. Acid deposition onto surface waters and soils with low buffering capacity may influence the availability of lead for uptake by plants and animals, and this may merit investigation at susceptible sites. The biological significance of chronic low-level lead exposure to wildlife is sometimes difficult to quantify. Animals living in urban environments or near point sources of lead emission are inevitably subject to greater exposure to lead and enhanced risk of lead poisoning. Increasingly strict controls on lead emissions in many countries have reduced exposure to lead from some sources

  15. ALICE: Simulated lead-lead collision

    CERN Document Server

    2003-01-01

    This track is an example of simulated data modelled for the ALICE detector on the Large Hadron Collider (LHC) at CERN, which will begin taking data in 2008. ALICE will focus on the study of collisions between nuclei of lead, a heavy element that produces many different particles when collided. It is hoped that these collisions will produce a new state of matter known as the quark-gluon plasma, which existed billionths of a second after the Big Bang.

  16. Organic Lead Toxicology

    Directory of Open Access Journals (Sweden)

    Jiří Patočka

    2008-01-01

    Full Text Available Lead is one of the oldest known and most widely studied occupational and environmental poison. Despite intensive study, there is still debate about the toxic effects of lead, both from low-level exposure in the general population owing to environmental pollution and historic use of lead in paint and plumbing and from exposure in the occupational setting. Significant position have organic lead compounds used more than 60 years as antiknock additives in gasoline. Chemical and toxicological characteristics of main tetraalkyl leads used as gasoline additives are discussed in this article. The majority of industries historically associated with high lead exposure have made dramatic advances in their control of occupational exposure. However, cases of unacceptably high exposure and even of frank lead poisoning are still seen, predominantly in the demolition and tank cleaning industries. Nevertheless, in most industries blood lead levels have declined below levels at which signs or symptoms are seen and the current focus of attention is on the subclinical effects of exposure. The significance of some of these effects for the overt health of the workers is often the subject of debate. Inevitably there is pressure to reduce lead exposure in the general population and in working environments, because current studies show that no level of lead exposure appears to be a ‘safe’ and even the current ‘low’ levels of exposure, especially in children, are associated with neurodevelopmental deficits.

  17. Lead-Free Piezoelectrics

    CERN Document Server

    Nahm, Sahn

    2012-01-01

    Ecological restrictions in many parts of the world are demanding the elimination of Pb from all consumer items. At this moment in the piezoelectric ceramics industry, there is no issue of more importance than the transition to lead-free materials. The goal of Lead-Free Piezoelectrics is to provide a comprehensive overview of the fundamentals and developments in the field of lead-free materials and products to leading researchers in the world. The text presents chapters on demonstrated applications of the lead-free materials, which will allow readers to conceptualize the present possibilities and will be useful for both students and professionals conducting research on ferroelectrics, piezoelectrics, smart materials, lead-free materials, and a variety of applications including sensors, actuators, ultrasonic transducers and energy harvesters.

  18. Lead and the skin

    Energy Technology Data Exchange (ETDEWEB)

    Allen, B.R.; Moore, M.R.; Hunter, J.A.A.

    1975-01-01

    The increasing use of lead will continue to give rise to problems of toxicity. Protective measures have resulted in florid lead poisoning becoming rare. Attention has recently turned to the possibility of prolonged exposure to low doses of lead causing morbidity in the absence of the classical clinical features of poisoning. Lead is absorbed mostly through the lungs and gastrointestinal tract. Some is also absorbed through the skin but with inorganic compounds the amount is small. Shortly after the most widely used compound, tetraethyl lead, was first manufactured, cases of toxicity began to occur. Manufacture was forbidden until plant design produced greater safety. Significant absorption can occur through the skin. The hazard to those handling leaded gasoline in a normal manner is probably small, mainly because 95 percent of a dose applied to the open skin surface evaporates. Hair has been used as a biopsy material to assess lead exposure. The biological effects of lead poisoning are discussed, including the synergistic effects of lead and agents provoking porphyria.

  19. EFFECT OF LEAD ACETATE

    African Journals Online (AJOL)

    MICROSOFT

    The project was conducted to evaluate the effect of lead administered as lead acetate at different dosage levels via drinking water in broiler chicks. Thirty-five healthy chicks were divided into seven groups (five chicks each) and one group was kept as un-medicated control. Groups A, B, C, D, E and F were medicated with ...

  20. Leading Acquisition Reform

    Science.gov (United States)

    2011-03-22

    Army and Undersecretary of Defense for Acquisition, for a reduction of the Excalibur and Accelerated Precision Mortar initiative rounds.25...Can’t Dance? Leading a Great Enterprise Through Dramatic Change, (New York: HarperCollins Publishers, 2003), 235. 13 John P. Kotter , Leading Change

  1. Developmental immunotoxicology of lead.

    Science.gov (United States)

    Dietert, Rodney R; Lee, Ji-Eun; Hussain, Irshad; Piepenbrink, Michael

    2004-07-15

    The heavy metal, lead, is a known developmental immunotoxicant that has been shown to produce immune alterations in humans as well as other species. Unlike many compounds that exert adverse immune effects, lead exposure at low to moderate levels does not produce widespread loss of immune cells. In contrast, changes resulting from lead exposure are subtle at the immune cell population level but, nevertheless, can be functionally dramatic. A hallmark of lead-induced immunotoxicity is a pronounced shift in the balance in T helper cell function toward T helper 2 responses at the expense of T helper 1 functions. This bias alters the nature and range of immune responses that can be produced thereby influencing host susceptibility to various diseases. Immunotoxic responses to lead appear to differ across life stages not only quantitatively with regard to dose response, but also qualitatively in terms of the spectrum of immune alterations. Experimental studies in several lab animal species suggest the latter stages of gestation are a period of considerable sensitivity for lead-induced immunotoxicity. This review describes the basic characteristics of lead-induced immunotoxicity emphasizing experimental animal results. It also provides a framework for the consideration of toxicant exposure effects across life stages. The existence of and probable basis for developmental windows of immune hyper-susceptibility are presented. Finally, the potential for lead to serve as a perinatal risk factor for childhood asthma as well as other diseases is considered.

  2. Lead - nutritional considerations

    Science.gov (United States)

    ... lead soldered cans goes into effect. If imported wine containers have a lead foil wrapper, wipe the rim and neck of the bottle with a towel moistened with lemon juice, vinegar, or wine before using. DO NOT store wine, spirits, or ...

  3. Lead toxicity: Current concerns

    Energy Technology Data Exchange (ETDEWEB)

    Goyer, R.A. (Univ. of Western Ontario, London (Canada))

    1993-04-01

    Over the 20-year period since the first issue of Environmental Health Perspectives was published, there has been considerable progress in the understanding of the potential toxicity of exposure to lead. Many of these advances have been reviewed in published symposia, conferences, and review papers in EHP. This brief review identifies major advances as well as a number of current concerns that present opportunities for prevention and intervention strategies. The major scientific advance has been the demonstration that blood lead (PbB) levels of 10-15 micrograms/dL in newborn and very young infants result in cognitive and behavioral deficits. Further support for this observation is being obtained by prospective or longitudinal studies presently in progress. The mechanism(s) for the central nervous system effects of lead is unclear but involve lead interactions within calcium-mediated intracellular messenger systems and neurotransmission. Effects of low-level lead exposure on blood pressure, particularly in adult men, may be related to the effect of lead on calcium-mediated control of vascular smooth muscle contraction and on the renin-angiotensin system. Reproductive effects of lead have long been suspected, but low-level effects have not been well studied. Whether lead is a carcinogen or its association with renal adenocarcinoma is a consequence of cystic nephropathy is uncertain. Major risk factors for lead toxicity in children in the United States include nutrition, particularly deficiencies of essential metals, calcium, iron, and zinc, and housing and socioeconomic status. A goal for the year 2000 is to reduce prevalence of blood lead levels exceeding 15 micrograms/dL. 97 refs.

  4. Re-engineering nalidixic acid's chemical scaffold: A step towards the development of novel anti-tubercular and anti-bacterial leads for resistant pathogens.

    Science.gov (United States)

    Peraman, Ramalingam; Varma, Raghu Veer; Reddy, Y Padmanabha

    2015-10-01

    Occurrence of antibacterial and antimycobacterial resistance stimulated a thrust to discover new drugs for infectious diseases. Herein we report the work on re-engineering nalidixic acid's chemical scaffold for newer leads. Stepwise clubbing of quinoxaline, 1,2,4-triazole/1,3,4-oxadiazole with nalidixic acid yielded better compounds. Compounds were screened against ciprofloxacin resistant bacteria and Mycobacterium tuberculosis H37Rv species. Results were obtained as minimum inhibitory concentration, it was evident that molecule with quinoxaline linked azide as side chain served as antitubercular lead (<6.25 μg/ml) whilst molecule with oxadiazole or triazole linked quinoxaline side chain served as anti-bacterial lead. Few compounds were significantly active against Escherichia coli and Proteus vulgaris with MIC less than 0.06 μg/ml and relatively potent than ciprofloxacin. No true compound was potentially active against Salmonella species as compared to amoxicillin. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Lead User Innovation

    DEFF Research Database (Denmark)

    Brem, Alexander; Larsen, Henry

    2015-01-01

    User innovation and especially the integration of lead users is a key topic in the innovation management literature of recent years. This paper contributes by providing a rare perspective into what easily could be seen as innovation failure, shown from two perspectives. We show how a lack of shared...... imagination hampers participation and kills innovation between interdependent stakeholders at the threshold between invention and innovation in practice. We present a first case in the fun-sport industry where an external lead user and diverse firm representatives in different functions fail to create......, deliver and capture the value of an innovatively new device together. From the perspective of the lead user, we show antecedents and effects of social interaction between organizational actors and the lead user on the development of social capital, especially trust and shared imagination. The second case...

  6. Magnesium Diboride Current Leads

    Science.gov (United States)

    Panek, John

    2010-01-01

    A recently discovered superconductor, magnesium diboride (MgB2), can be used to fabricate conducting leads used in cryogenic applications. Dis covered to be superconducting in 2001, MgB2 has the advantage of remaining superconducting at higher temperatures than the previously used material, NbTi. The purpose of these leads is to provide 2 A of electricity to motors located in a 1.3 K environment. The providing environment is a relatively warm 17 K. Requirements for these leads are to survive temperature fluctuations in the 5 K and 11 K heat sinks, and not conduct excessive heat into the 1.3 K environment. Test data showed that each lead in the assembly could conduct 5 A at 4 K, which, when scaled to 17 K, still provided more than the required 2 A. The lead assembly consists of 12 steelclad MgB2 wires, a tensioned Kevlar support, a thermal heat sink interface at 4 K, and base plates. The wires are soldered to heavy copper leads at the 17 K end, and to thin copper-clad NbTi leads at the 1.3 K end. The leads were designed, fabricated, and tested at the Forschungszentrum Karlsruhe - Institut foer Technische Physik before inclusion in Goddard's XRS (X-Ray Spectrometer) instrument onboard the Astro-E2 spacecraft. A key factor is that MgB2 remains superconducting up to 30 K, which means that it does not introduce joule heating as a resistive wire would. Because the required temperature ranges are 1.3-17 K, this provides a large margin of safety. Previous designs lost superconductivity at around 8 K. The disadvantage to MgB2 is that it is a brittle ceramic, and making thin wires from it is challenging. The solution was to encase the leads in thin steel tubes for strength. Previous designs were so brittle as to risk instrument survival. MgB2 leads can be used in any cryogenic application where small currents need to be conducted at below 30 K. Because previous designs would superconduct only at up to 8 K, this new design would be ideal for the 8-30 K range.

  7. Lead toxicity in plants

    OpenAIRE

    Sharma, Pallavi; Dubey, Rama Shanker

    2005-01-01

    Contamination of soils by heavy metals is of widespread occurrence as a result of human, agricultural and industrial activities. Among heavy metals, lead is a potential pollutant that readily accumulates in soils and sediments. Although lead is not an essential element for plants, it gets easily absorbed and accumulated in different plant parts. Uptake of Pb in plants is regulated by pH, particle size and cation exchange capacity of the soils as well as by root exudation and other physico-che...

  8. Synthesis of 6-Amino-5-cyano-1,4-disubstituted-2(1H-Pyrimidinones via Copper-(I-catalyzed Alkyne-azide ‘Click Chemistry’ and Their Reactivity

    Directory of Open Access Journals (Sweden)

    Fethi Zribi

    2010-12-01

    Full Text Available In this paper we present the room temperature synthesis of a novel serie of 1,4-disubstituted-1,2,3-triazoles 4a-l by employing the (3 + 2 cycloaddition reaction of pyrimidinones containing alkyne functions with different model azides in the presence of copper sulphate and sodium ascorbate. To obtain the final triazoles, we also synthesized the major precursors 6-amino-5-cyano-1,4-disubstituted-2(1H-pyrimidinones 3a-r from ethyl 2,2-dicyanovinylcarbamate derivatives 2a-c and various primary aromatic amines containing an alkyne group. The triazoles were prepared in good to very good yields.

  9. Síntese e atividade citotóxica de alguns azido-ciclopaladados estabilizados com ligantes bifosfínicos Synthesis and cytotoxicity of some cyclometallated palladium (II complexes containing coordinated azide and diphosphines

    Directory of Open Access Journals (Sweden)

    Antonio Carlos Fávero Caires

    1999-06-01

    Full Text Available Some cyclopalladated compounds containing the azido group ligand and the (C-N ring of N,N-dimethylbenzylamine have been prepared by bridge opening reactions of dimmer azide complex precursor with some diphosphines in different stoichiometric quantities. The neutral or ionic, mono or binuclear complexes synthesized were characterized by elemental analyses, I. R. spectroscopy and NMR techniques. The series of complexes was screened for cytotoxicity against a panel three human tumour cells lines(C6,Hep-2,HeLa. All complexes were found to be cytotoxic (IC50 at µM concentrations while one complex having the coordination bond N-Pd ruptured also displayed some differential cytotoxicity.

  10. Rhodium(II-Catalysed Intramolecular O-H Insertion of a-Diazo-g-Azido-d-Hydroxy-b-Ketoesters: Evidence for a Novel Sigmatropic Rearrangement of an Allylic Azide Intermediate

    Directory of Open Access Journals (Sweden)

    Padwa Albert

    1999-01-01

    Full Text Available The Rh2(OAc4 catalyzed intramolecular O-H insertion reaction of delta-hydroxy-alpha-diazoesters affords 3(2H-furanone-2-carboxylates in good yield but with moderate selectivity (d.e. ca 60%. The initially formed 2,5-substituted cis-furanones were found to epimerize to the corresponding 2,5-trans isomers when subjected to silica gel chromatography. The Rh2(OAc4 catalyzed decomposition of gamma-azido-delta-hydroxy-alpha-diazoesters also furnished 3(2H-furanone-2-carboxylates. These compounds are derived by a sequential O-H insertion reaction followed by a concerted [3,3]-sigmatropic shift of the allylic azide intermediate.

  11. Leading through Conflict

    Science.gov (United States)

    Gerzon, Mark

    2006-01-01

    This article talks about leading significant learning opportunities through conflict of ideas in a school system. Catalyzing school change can turn emotional differences of opinion into learning opportunities. Leaders who want to deal effectively with these challenging, often tense situations need to be more than good managers. They need to be…

  12. Turning lead into gold

    DEFF Research Database (Denmark)

    Jensen, Steffen Moltrup Ernø

    For years the field of entrepreneurship has been blinded by the alchemical promise of turning lead into gold, of finding the ones most likely to become the next Branson, Zuckerberg or Gates. The promise has been created in the midst of political and scientific agendas where certain individuals...

  13. Relational Perspectives on Leading

    DEFF Research Database (Denmark)

    Relational Perspectives on Leading discusses leadership from a relational and social constructionism perspective as practiced on an everyday basis between people. The book pursues a fast growing, practice-based approach - particularly within the Anglo-Saxon parts of the world - to organization...

  14. Relational Perspectives on Leading

    DEFF Research Database (Denmark)

    Larsen, Mette Vinther; Rasmussen, Jørgen Gulddahl

    2015-01-01

    Relational Perspectives on Leading discusses leadership from a relational and social constructionism perspective as practiced on an everyday basis between people. The book pursues a fast growing, practice-based approach - particularly within the Anglo-Saxon parts of the world - to organization...

  15. [Effects of Shenwu capsule on learning-memory ability and cholinergic function of brain in AD-like rat model induced by chronic infusion of sodium azide by minipump].

    Science.gov (United States)

    Zhang, Lan; Zhang, Ru-Yi; Li, Ya-Li; Zhang, Li; Ye, Cui-Fei; Li, Lin

    2013-05-01

    Because of the proposed importance of mitochondrial cytochrome C oxidase (COX) decrease in Alzheimer's disease (AD) , the protective effect of Shenwu capsule on mitochondrial deficiency model rats and its pharmacological mechanism were investigated in present study. Rats were administered with azide at 1 mg . kg-1 . h-1 subcutaneously via an Alzet minipump for 30 days. Tweny-four hours after the operation, the rats were administered intragastrically by Shenwu capsule with the dose of 0. 45, 0. 9 and 1. 8 g . kg-1 . d-1 for one month. Then learning-memory ability was determined by the watermaze test and passive avoidance tests. The activity of choline-acetyl-transfertase(ChAT) and acetylcholinesterase (AChE) in hippocampus and cortex of rats were measured by radiochemical method and hydroxylamine colorimetry separately. M-cholinergic receptor binding ability (M-binding) was assayed by radio binding. Chronic infusion of sodium azide via minipump induced learning-memory deficiency of rats. Both ChAT activity and M-binding decreased in hippocampus and cortex of model rats, however, the activity of AChE increased in hippocampus and was not affected at the cortex. As the result, the cholinergic function of the brain decreased in model rats. Shenwu capsule significantly improved learning and memory ability and the mechanism may be related with the improved cholinergic function in model brain: ChAT activity and M-binding significantly increased in Shenwu treated groups compared with model group; and the increased activity of AChE in hippocampus returned to normal. Mitochondria, especially mitochondrial cytochrome C oxidase, may play the key role in the early event of AD. Chronic, partial in vivo inhibition of mitochondrial cytochrome C oxidase in rats provides a suitable model mimicking several aspects of AD. Shenwu capsule indicate effectiveness in AD-like mitochondrial deficiency model rats, so it would be applied in the treatment of AD.

  16. Managing, Leading, and Bossing

    Science.gov (United States)

    2011-08-01

    Defense AT&L: July–August 2011 76 Managing , Leading, and Bossing Stan Emelander Boss Manager Leader Emelander is a project manager in the Army’s...and management . He is level II certified in program management and level I in systems engineering. Leaders fascinate us. From the smallest shop to...me about your boss” will work. Another great question is, “What’s the difference between a leader and a manager ?” Early in my career, I thought there

  17. Lead tungstate scintillation material

    CERN Document Server

    Annenkov, A N; Lecoq, P

    2002-01-01

    In this paper we summarize the results of a research programme on lead-tungstate (PWO) crystals performed by the CMS Collaboration at CERN, as well as by other groups who promoted the progress of the PWO scintillation crystal technology. Crystal properties, mass production technology, scintillation mechanism, origin of colouring, defects in crystal and radiation induced phenomena, light yield improvement and results of beam tests are described. (96 refs).

  18. Problem of lead in petrol: The effect of triethyl lead

    Energy Technology Data Exchange (ETDEWEB)

    Roederer, G.

    1985-10-01

    Triethyl lead is a highly toxic derivate of the anti-knock agent tetraethyl lead. Contrary to anorganic lead compounds triethyl lead causes serious disorders in the central nervous system of poisoned mammals leading to dramatic mental changes. Triethyl lead destroys microtubuli in the cells of plants and animals. It is assumed that the neurotoxic effect of triethyl lead is caused by its interacting with the microtubuli of the nerves (neurotubuli) and their subsequent destruction.

  19. lead glass brick

    CERN Multimedia

    When you look through the glass at a picture behind, the picture appears raised up because light is slowed down in the dense glass. It is this density (4.06 gcm-3) that makes lead glass attractive to physicists. The refractive index of the glass is 1.708 at 400nm (violet light), meaning that light travels in the glass at about 58% its normal speed. At CERN, the OPAL detector uses some 12000 blocks of glass like this to measure particle energies.

  20. Leading change: 2--planning.

    Science.gov (United States)

    Kerridge, Joanna

    National initiatives have outlined the importance of involving frontline staff in service improvement, and the ability to influence and manage change has been identified as an essential skill for delivering new models of care. Nurses often have to take the lead in managing change in clinical practice. The second in a three-part series is designed to help nurses at all levels develop the knowledge and skills to function as change agents within their organisations. This article focuses on planning the change and dealing with resistance.

  1. Lead and lead-based alloys as waste matrix materials

    Energy Technology Data Exchange (ETDEWEB)

    Arustamov, A.E.; Ojovan, M.I.; Kachalov, M.B.

    1999-07-01

    Metals and alloys with relatively low melting temperatures such as lead and lead-based alloys are considered in Russia as prospective matrices for encapsulation of spent nuclear fuel in containers in preparation for final disposal in underground repositories. Now lead and lead-based alloys are being used for conditioning spent sealed radioactive sources at radioactive waste disposal facilities.

  2. HAIR LEAD CONCENTRATION IN NAKHLAK LEAD MINERS VERSUS CONTROL GROUP

    Directory of Open Access Journals (Sweden)

    N IZADI

    2002-03-01

    Full Text Available Introduction. Lead poisoning is a major problem in environmental health. Exposure can occur via air, soil, food and water. Occupational exposure is the most common source of lead poisoning in adults. Lead miners are exposed to an additional source of poisoning in long term. Hair analysis may be used to evaluate chronic lead toxicity. This study compare the hair lead concentration in Nakhlak lead miners and Mohammadieh people who live 130 km far from the lead mine. Methods. Hair samples from 24 Nakhlak lead miners and 26 adult men of Mohammadieh village were gathered, washed by detergent and distilled water and dissolved by wet digestion. Lead concentrations of the samples were measured by flame atomic absorption spectroscopy. Results. There was a significant difference between hair lead concentration of Nakhlak lead miners and Mohammadieh people (P < 0.001. The mean of lead concentrations were 52.43±27.7 µg/g (mean ± SD and 17.32±3.43 µg/g hair of the lead mine workers and the Mohammadieh people, respectively. There was also a significant regression between the number of exposure years and the lead concentration of hair in Nakhlak lead miners (P < 0.001, r=0.8. Discussion. Presence of lead compounds in work environment especially in the air may be an important factor for the difference between hair lead concentration of Nakhlak lead miners and Mohammadieh people. However, the hair lead concentration in Mohammadieh people is also reasonably high. It means that these people are also exposed to lead through the other sources e.g. food, soil, water and air.

  3. Human lead metabolism: Chronic exposure, bone lead and physiological models

    Science.gov (United States)

    Fleming, David Eric Berkeley

    Exposure to lead is associated with a variety of detrimental health effects. After ingestion or inhalation, lead may be taken up from the bloodstream and retained by bone tissue. X-ray fluorescence was used to make in vivo measurements of bone lead concentration at the tibia and calcaneus for 367 active and 14 retired lead smelter workers. Blood lead levels following a labour disruption were used in conjunction with bone lead readings to examine the endogenous release of lead from bone. Relations between bone lead and a cumulative blood lead index differed depending on time of hiring. This suggests that the transfer of lead from blood to bone has changed over time, possibly as a result of varying exposure conditions. A common polymorphism in the δ-aminolevulinate dehydratase (ALAD) enzyme may influence the distribution of lead in humans. Blood lead levels were higher for smelter workers expressing the more rare ALAD2 allele. Bone lead concentrations, however, were not significantly different. This implies that a smaller proportion of lead in blood is distributed to tissue for individuals expressing the ALAD2 allele. The O'Flaherty physiological model of lead metabolism was modified slightly and tested with input from the personal exposure histories of smelter workers. The model results were consistent with observation in tern of endogenous exposure to lead and accumulation of lead in cortical bone. Modelling the calcaneus as a trabecular bone site did not reproduce observed trends. variations in lead metabolism between different trabecular sites may therefore be significant. The model does not incorporate a genetic component, and its output did not reflect observed differences in this respect. This result provides further support for the influence of the ALAD polymorphism on lead metabolism. Experimental trials with a digital spectrometer revealed superior energy resolution and count throughput relative to the conventional X-ray fluorescence system. The associated

  4. Drowning: a leading killer!

    Directory of Open Access Journals (Sweden)

    Nuno Domingos Garrido

    2016-10-01

    Full Text Available Drowning kills at least 372,000 people worldwide every year and is the 3rd leading cause of unintentional death, accounting for 7% of all deaths stemming from accidents (WHO, 2014. Conceptually, “drowning” is a complex and multi-faceted phenomenon, characterized as a chain of events (Bierens, 2006. Drowning is defined as the process of experiencing respiratory impairment from immersion or submersion in liquid. Research on drowning as a phenomenon presents several difficulties - most of all, that global data concerning the number of occurrences are not accurate. Nevertheless, detailed analysis of the registered incidents allows the identification of risk factors of drowning. An in-depth analysis of the risk factors is the basis for the creation of targeted and effective strategies to prevent drowning. Due to variability of situations which could lead to a drowning episode, experts suggest the adoption of a multi-layer prevention model, rather than opting for isolated measures, since no single measure can prevent all deaths and injuries caused by submersion. Among the preventive measures we would like to emphasize instruction in swimming and water safety. So, what does "knowing how to swim" really mean? Some authors define mastery of this competence as swimming a given distance, while others put the emphasis on how this/any given distance is swum (Stallman, Junge, & Blixt, 2008. It has long been realized that there is no contradiction between learning those competencies which make a person less susceptible to drowning and those competencies which prepare the path towards higher levels of performance and competition. Aquatic movement researchers and practitioners and drowning prevention researchers and practitioners, share in the responsibility for drowning prevention though they are often unaware of it. The question “What should be taught to children?” is too infrequently asked. There remains great variation in what is taught and programs

  5. Leading Your Leaders

    Science.gov (United States)

    Hale, Wayne N.

    2008-01-01

    life is good. More often when an unbelievably difficult test fails, we are left with a very long discussion of why and what was wrong in the design or execution of the test. Make sure that the test is well defined. Even then, it is important to explain to your leaders what inherent accuracy (or error) the test conditions or equipment have and what the assumptions or initial conditions were for the test. Test results without a good understanding of the test's accuracy or the pedigree of the test assumptions are worth very little. Finally, there is flight test data. Always limited, never at the edge of the envelope, it still shows how the real hardware works in a combined environment. Flight experience is dangerous because it typically doesn't show how close to the edge of the cliff the equipment is operating, but it does demonstrate how the hardware really works. A flight test is the ultimate test, again taken with the knowledge that it is probably not the extreme but something more like the middle of the environmental and systems performance. Good understanding of a problem and its solution always relies on a combination of all these methods. Be sure to lead your leaders by using all the tools you have at your disposal. At the end of the day, decisions in space flight always come down to a risk trade. Our business is not remotely safe, not in the sense that the public, the media, or our legislators use the term. Everything we do has a risk, cost, schedule, or performance trade-off. For your leaders to make an appropriate decision, you need to educate them, lead them, talk with them, and engage them in the discussion until full understanding takes place. It's your job. *

  6. Leading clever people.

    Science.gov (United States)

    Goffee, Rob; Jones, Gareth

    2007-03-01

    In an economy driven by ideas and intellectual know-how, top executives recognize the importance of employing smart, highly creative people. But if clever people have one defining characteristic, it's that they do not want to be led. So what is a leader to do? The authors conducted more than 100 interviews with leaders and their clever people at major organizations such as PricewaterhouseCoopers, Cisco Systems, Novartis, the BBC, and Roche. What they learned is that the psychological relationships effective leaders have with their clever people are very different from the ones they have with traditional followers. Those relationships can be shaped by seven characteristics that clever people share: They know their worth--and they know you have to employ them if you want their tacit skills. They are organizationally savvy and will seek the company context in which their interests are most generously funded. They ignore corporate hierarchy; although intellectual status is important to them, you can't lure them with promotions. They expect instant access to top management, and if they don't get it, they may think the organization doesn't take their work seriously. They are plugged into highly developed knowledge networks, which both increases their value and makes them more of a flight risk. They have a low boredom threshold, so you have to keep them challenged and committed. They won't thank you--even when you're leading them well. The trick is to act like a benevolent guardian: to grant them the respect and recognition they demand, protect them from organizational rules and politics, and give them room to pursue private efforts and even to fail. The payoff will be a flourishing crop of creative minds that will enrich your whole organization.

  7. [Fe(III)(F(20)-tpp)Cl] is an effective catalyst for nitrene transfer reactions and amination of saturated hydrocarbons with sulfonyl and aryl azides as nitrogen source under thermal and microwave-assisted conditions.

    Science.gov (United States)

    Liu, Yungen; Che, Chi-Ming

    2010-09-10

    [Fe(III)(F(20)-tpp)Cl] (F(20)-tpp=meso-tetrakis(pentafluorophenyl)porphyrinato dianion) is an effective catalyst for imido/nitrene insertion reactions using sulfonyl and aryl azides as nitrogen source. Under thermal conditions, aziridination of aryl and alkyl alkenes (16 examples, 60-95 % yields), sulfimidation of sulfides (11 examples, 76-96 % yields), allylic amidation/amination of α-methylstyrenes (15 examples, 68-83 % yields), and amination of saturated C--H bonds including that of cycloalkanes and adamantane (eight examples, 64-80 % yields) can be accomplished by using 2 mol % [Fe(III)(F(20)-tpp)Cl] as catalyst. Under microwave irradiation conditions, the reaction time of aziridination (four examples), allylic amination (five examples), sulfimidation (two examples), and amination of saturated C--H bonds (three examples) can be reduced by up to 16-fold (24-48 versus 1.5-6 h) without significantly affecting the product yield and substrate conversion.

  8. Síntese e caracterização do polímero energético Metil Azoteto de Glicidila (GAP via análises instrumentais Characterization of energetic Methyl Glycidyl Azide Polymer

    Directory of Open Access Journals (Sweden)

    Jairo Sciamareli

    2009-06-01

    Full Text Available Na área aeroespacial é constante a pesquisa em busca de novos materiais que permitam um melhor desempenho de foguetes, mísseis e explosivos. Entre outros, compostos mais energéticos, de maior estabilidade térmica e/ou química, menos agressivos ao meio ambiente, de menor custo e de mais fácil manuseio. Um destes materiais é o metil azoteto de glicidila (GAP, que pode ser utilizado para produzir propelentes mais energéticos e/ou sem fumaça, bem como composições explosivas de baixa sensibilidade. O GAP foi sintetizado e caracterizado por análises FT-IR, elementar, cromatográfica de permeação de gel e térmica.To obtain more energetic, safe propellants, with improved performance, better mechanical properties and low cost, new materials have been researched and tested. One of these materials is Methyl Glycidyl Azide Polymer (GAP. It can be used to make energetic and/or smokeless propellants as well as composite explosives with low sensitivity. GAP was synthesized and characterized by FT-IR, elemental analysis, gel permeation chromatography (GPC and thermal analysis.

  9. Safety and Health Topics: Lead

    Science.gov (United States)

    ... gray, heavy metal that occurs naturally in the Earth’s crust. Lead was one of the first metals ... even at very low blood lead levels. Pregnant women or those who might become pregnant must avoid ...

  10. Lead Exposure Hazard Management Guide

    Science.gov (United States)

    1993-12-01

    effects of lead on humans beings have been known for many years. Acute overexposure to lead can kill in a matter of days. Chronic overexposure to lead in...8217--: -7 Thserconnsa*Im will help achive one of dh nationial health objectives specified by Healthy Peple 2000, which is to eliminate exposures that

  11. Lead poisoning in an adult: lead mobilization by pregnancy?

    Science.gov (United States)

    Riess, Matthias L; Halm, Josiah K

    2007-08-01

    We report a case of acute lead poisoning in an adult female who had last been exposed to lead 7 years ago. She presented with abdominal pain, knee pain, and neurological symptoms, hypertension, chronic kidney disease, and anemia with basophilic stippling and lead gum lines. Compared to during her recent pregnancy, her lead level had almost tripled in 5 months to 81 mcg/dL. Chelation therapy was initiated and improved the patient's symptoms and lead level significantly. In the absence of any new lead exposure or other reasons for increased bone turnover, this acute lead increase was likely due to skeletal mobilization caused by increased resorption from mineralized tissue during and after her pregnancy. This case report illustrates the seriousness of long-term health effects associated with lead poisoning at a multi-organ level, even years after the initial exposure. Thus, patient care should not be limited to the acute treatment of increased lead levels, but also include prevention of increased mobilization and bone turnover and appropriate patient education. In this context, we review various aspects of lead toxicity, especially during pregnancy and lactation.

  12. Determining lead sources in Mexico using the lead isotope ratio

    Directory of Open Access Journals (Sweden)

    Chaudhary-Webb Madhu

    2003-01-01

    Full Text Available OBJECTIVE: Lead poisoning can, in some cases, be traced to a specific route or source of exposure on the basis of the individual's blood lead isotope ratio. To assess the major source of lead exposure among women residing in Mexico City, we compared blood, ceramic, and gasoline lead isotope ratios. MATERIAL AND METHODS: The study population, randomly selected from participants of a large trial, (1/1996-12/1996 comprised of 16 women whose lead levels exceeded 10 µg/dl and who reported using lead-glazed ceramics. Lead isotope ratios were performed on a Perkin Elmer 5000 Inductively Coupled Plasma Mass Spectrometer (ICP-MS interfaced with a Perkin Elmer HGA-600MS Electrothermal Vaporization System (ETV. RESULTS: The isotope ratios (206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb of both the blood specimens and their corresponding ceramic specimens were highly correlated, with r=0.9979, r²=0.9958, r=0.9957, r²=0.9915 and r=0.9945, r²=0.9890 values for the three isotope ratios, respectively, suggesting that the lead exposure most likely resulted from the use of these ceramic. Measurements of lead isotope ratios from leaded gasoline in use at the time of blood sampling, differed from those in blood and ceramics. CONCLUSIONS: Determining lead isotope ratios can be an efficient tool to identify a major source of lead exposure and to support the implementation of public health prevention and control measures.

  13. Chronic lead poisoning in horses

    Energy Technology Data Exchange (ETDEWEB)

    Knight, H.D.; Burau, R.G.

    1973-05-01

    Chronic lead poisoning in horses was manifested as anorexia, loss of body weight, muscular weakness, anemia, laryngeal hemiplegia, and, terminally, inhalation pneumonia. Some deaths were sudden and unexplained. The lead content in liver specimens from 10 horses was greater than that considered indicative of lead intoxication; however, the lead content of blood was equivocal. The most conclusive laboratory finding was increased urine lead concentration after chelation therapy. The concentration of lead in a sample of vegetation considered to be representative of what a horse would eat if he was grazing in the area sampled was 325 ppM (oven-dry basis). It was determined that a 450-kg horse grazing grass of this lead content would consume 2.9 Gm of lead daily (6.4 mg/kg of body weight), an amount considered toxic for horses. Leaching lowered the calcium content of the forage but failed to reduce the lead concentration of the plants significantly, thus opening the possibility that winter rains might have influenced the onset of poisoning. Airborne fallout from a nearby lead smelter was proposed as the primary mode of pasture contamination.

  14. Childhood lead poisoning: an overview.

    Science.gov (United States)

    Hon, K L; Fung, C K; Leung, A Kc

    2017-12-01

    Childhood lead poisoning is a major public health concern in many countries. In 2015, the Hong Kong SAR Government and its citizens faced a major public health crisis due to the presence of lead in the drinking water of a number of public housing estates. Fortunately, no child was diagnosed with lead poisoning that required treatment with chelation. Lead is a ubiquitous, naturally occurring material that exists in air, dust, soil, and water. It is also widely present in industrial products including petrol, paints, ceramics, food cans, candies, cosmetics, traditional remedies, batteries, solder, stained glass, crystal vessels, ammunition, ceramic glazes, jewellry, and toys. It can also be found in human milk. There is no safe blood lead level and it may be impossible to completely eliminate lead from any city. Hence routine measurement of blood lead levels is not considered useful. Acute poisoning, especially with encephalopathy, deserves immediate medical treatment in hospital. Chelation therapy is recommended if blood lead level is 45 μg/dL or higher. For blood levels between 20 and 45 μg/dL, treatment is indicated if the child is symptomatic. For blood levels below 20 μg/dL in otherwise asymptomatic children, the principle of treatment is to provide long-term neurodevelopmental follow-up and counselling. In all cases, immediate removal of the source of lead exposure is vital. Even low levels of lead exposure can significantly impair learning, educational attainment, and neurodevelopment.

  15. Lead toxicity in battery workers.

    Science.gov (United States)

    Qasim, Saeeda Fouzia; Baloch, Malka

    2014-11-01

    Lead poisoning is a medical condition caused by increased levels of lead in the body. Routes of exposure include contaminated air, water, soil, food and consumer products. Occupational exposure is the main cause of lead poisoning in the adults. Two cases of occupational lead poisoning in adult battery workers are hereby presented. Both male patients had initial non-specific symptoms of intermittent abdominal pain, fatigue and headache for 6 - 8 years. Later on, they developed psychosis, slurred speech, tremors of hands and initially underwent treatment for Parkinsonism and Wilson's disease because of clinical misdiagnosis. They were diagnosed with lead poisoning later and were treated successfully with lead chelator (CaNa2 EDTA).

  16. Taking the Lead : Gender, Social Context and Preference to Lead

    NARCIS (Netherlands)

    Hong, A.P.C.I.; Schaafsma, J.; van der Wijst, P.J.

    Previous research has demonstrated that women tend to emerge as leaders less often than men. In the present study, we examined to what extent women's and men's preference to lead is influenced by social context. It was hypothesized that women have a less strong preference to lead than men in a

  17. Undue Lead Absorption and Lead Poisoning in Children: An Overview.

    Science.gov (United States)

    Lin-Fu, J. S.

    The toxic effects of lead, a useful metal ubiquitous in the human environment, have long been known. The occupational hazards of lead poisoning were well established by the early 19th century, but plumbism in children caused by paint ingestion was not reported until the turn of the century. Even in 1924, the child was said to live in a "lead…

  18. Leading Millennials Motivating And Leading Millennial Service Members

    Science.gov (United States)

    2016-02-20

    AIR WAR COLLEGE AIR UNIVERSITY LEADING MILLENNIALS MOTIVATING AND LEADING MILLENNIAL SERVICE MEMBERS by Joanne MacGregor, LTC...young adults ( Millennials ) serving in the U.S. military. These factors may not be readily apparent to Generation X and Y leaders. This paper argues...motivate, and discipline millennial subordinates while maximizing their talents through active and thoughtful professional development. 5

  19. Strategic Military Leaders - Leading Tomorrow

    Science.gov (United States)

    2008-02-29

    St ra te gy R es ea rc h Pr oj ec t STRATEGIC MILITARY LEADERS –LEADING TOMORROW BY COLONEL NG WAI KIT Singapore Army DISTRIBUTION...Strategic Military Leaders - Leading Tomorrow 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Ng Kit 5d. PROJECT...STRATEGIC MILITARY LEADERS – LEADING TOMORROW by Colonel Ng Wai Kit Singapore Army Dr. Leonard Wong Project

  20. Safe Leads and Lead Changes in Competitive Team Sports

    CERN Document Server

    Clauset, A; Redner, S

    2015-01-01

    We investigate the time evolution of lead changes within individual games of competitive team sports. Exploiting ideas from the theory of random walks, the number of lead changes within a single game follows a Gaussian distribution. We show that the probability that the last lead change and the time of the largest lead size are governed by the same arcsine law, a bimodal distribution that diverges at the start and at the end of the game. We also determine the probability that a given lead is "safe" as a function of its size $L$ and game time $t$. Our predictions generally agree with comprehensive data on more than 1.25 million scoring events in roughly 40,000 games across four professional or semi-professional team sports, and are more accurate than popular heuristics currently used in sports analytics.

  1. Safe leads and lead changes in competitive team sports

    Science.gov (United States)

    Clauset, A.; Kogan, M.; Redner, S.

    2015-06-01

    We investigate the time evolution of lead changes within individual games of competitive team sports. Exploiting ideas from the theory of random walks, the number of lead changes within a single game follows a Gaussian distribution. We show that the probability that the last lead change and the time of the largest lead size are governed by the same arcsine law, a bimodal distribution that diverges at the start and at the end of the game. We also determine the probability that a given lead is "safe" as a function of its size L and game time t . Our predictions generally agree with comprehensive data on more than 1.25 million scoring events in roughly 40 000 games across four professional or semiprofessional team sports, and are more accurate than popular heuristics currently used in sports analytics.

  2. High temperature superconductor current leads

    Science.gov (United States)

    Hull, John R.; Poeppel, Roger B.

    1995-01-01

    An electrical lead having one end for connection to an apparatus in a cryogenic environment and the other end for connection to an apparatus outside the cryogenic environment. The electrical lead includes a high temperature superconductor wire and an electrically conductive material distributed therein, where the conductive material is present at the one end of the lead at a concentration in the range of from 0 to about 3% by volume, and at the other end of the lead at a concentration of less than about 20% by volume. Various embodiments are shown for groups of high temperature superconductor wires and sheaths.

  3. Lead Poisoning in Wild Birds

    Science.gov (United States)

    Lahner, Lesanna L.; Franson, J. Christian

    2009-01-01

    Lead in its various forms has been used for thousands of years, originally in cooking utensils and glazes and more recently in many industrial and commercial applications. However, lead is a potent, potentially deadly toxin that damages many organs in the body and can affect all animals, including humans. By the mid 1990s, lead had been removed from many products in the United States, such as paint and fuel, but it is still commonly used in ammunition for hunting upland game birds, small mammals, and large game animals, as well as in fishing tackle. Wild birds, such as mourning doves, bald eagles, California condors, and loons, can die from the ingestion of one lead shot, bullet fragment, or sinker. According to a recent study on loon mortality, nearly half of adult loons found sick or dead during the breeding season in New England were diagnosed with confirmed or suspected lead poisoning from ingestion of lead fishing weights. Recent regulations in some states have restricted the use of lead ammunition on certain upland game hunting areas, as well as lead fishing tackle in areas frequented by common loons and trumpeter swans. A variety of alternatives to lead are available for use in hunting, shooting sports, and fishing activities.

  4. Lead Exposure: Weighing Down IQ.

    Science.gov (United States)

    Science News, 1979

    1979-01-01

    Researchers at Harvard Medical School and the Children's Hospital Medical Center in Boston have found that children exposed to high but well below identified toxic levels of lead show significantly lower IQ levels and a higher incidence of undesirable classroom behavior than do children with low levels of lead exposure. (Author/BB)

  5. Lead Exposure and Child Behavior.

    Science.gov (United States)

    Sciarillo, William G.; And Others

    1992-01-01

    Provides evidence of detrimental effects of lead exposure on child behavior at levels typical of present-day exposure. Behavior and lead-blood level were examined for 201 African-American children aged 2 through 5 years. A standardized parent report measure and consideration of maternal morale are features of study methodology. (SLD)

  6. Lead poisoning from souvenir earthenware.

    Science.gov (United States)

    Hellström-Lindberg, Eva; Björklund, Andreas; Karlson-Stiber, Christine; Harper, Pauline; Seldén, Anders I

    2006-02-01

    A case of massive lead poisoning from juice contained in a Greek earthenware jug as well as six satellite cases of high lead exposure of similar origin is reported. The intoxicated patient was successfully treated with dimercaptosuccinic acid. Ceramic producers should adhere to the longstanding European legislation.

  7. Lead-free primary explosives

    Science.gov (United States)

    Huynh, My Hang V.

    2010-06-22

    Lead-free primary explosives of the formula (cat).sub.Y[M.sup.II(T).sub.X(H.sub.2O).sub.6-X].sub.Z, where T is 5-nitrotetrazolate, and syntheses thereof are described. Substantially stoichiometric equivalents of the reactants lead to high yields of pure compositions thereby avoiding dangerous purification steps.

  8. Leading change: a concept analysis.

    Science.gov (United States)

    Nelson-Brantley, Heather V; Ford, Debra J

    2017-04-01

    To report an analysis of the concept of leading change. Nurses have been called to lead change to advance the health of individuals, populations, and systems. Conceptual clarity about leading change in the context of nursing and healthcare systems provides an empirical direction for future research and theory development that can advance the science of leadership studies in nursing. Concept analysis. CINAHL, PubMed, PsycINFO, Psychology and Behavioral Sciences Collection, Health Business Elite and Business Source Premier databases were searched using the terms: leading change, transformation, reform, leadership and change. Literature published in English from 2001 - 2015 in the fields of nursing, medicine, organizational studies, business, education, psychology or sociology were included. Walker and Avant's method was used to identify descriptions, antecedents, consequences and empirical referents of the concept. Model, related and contrary cases were developed. Five defining attributes of leading change were identified: (a) individual and collective leadership; (b) operational support; (c) fostering relationships; (d) organizational learning; and (e) balance. Antecedents were external or internal driving forces and organizational readiness. The consequences of leading change included improved organizational performance and outcomes and new organizational culture and values. A theoretical definition and conceptual model of leading change were developed. Future studies that use and test the model may contribute to the refinement of a middle-range theory to advance nursing leadership research and education. From this, empirically derived interventions that prepare and enable nurses to lead change to advance health may be realized. © 2016 John Wiley & Sons Ltd.

  9. Blood Test: Lead (For Parents)

    Science.gov (United States)

    ... Important? Top 10 Homework Tips Raising Confident Kids Blood Test: Lead KidsHealth > For Parents > Blood Test: Lead Print A A A What's in this ... locate a vein Helping Your Child Having a blood test is relatively painless. Still, many children are afraid ...

  10. Biosorption of lead phosphates by lead-tolerant bacteria as a mechanism for lead immobilization.

    Science.gov (United States)

    Rodríguez-Sánchez, Viridiana; Guzmán-Moreno, Jesús; Rodríguez-González, Vicente; Flores-de la Torre, Juan Armando; Ramírez-Santoyo, Rosa María; Vidales-Rodríguez, Luz Elena

    2017-08-01

    The study of metal-tolerant bacteria is important for bioremediation of contaminated environments and development of green technologies for material synthesis due to their potential to transform toxic metal ions into less toxic compounds by mechanisms such as reduction, oxidation and/or sequestration. In this study, we report the isolation of seven lead-tolerant bacteria from a metal-contaminated site at Zacatecas, México. The bacteria were identified as members of the Staphylococcus and Bacillus genera by microscopic, biochemical and 16S rDNA analyses. Minimal inhibitory concentration of these isolates was established between 4.5 and 7.0 mM of Pb(NO3)2 in solid and 1.0-4.0 mM of Pb(NO3)2 in liquid media. A quantitative analysis of the lead associated to bacterial biomass in growing cultures, revealed that the percentage of lead associated to biomass was between 1 and 37% in the PbT isolates. A mechanism of complexation/biosorption of lead ions as inorganic phosphates (lead hydroxyapatite and pyromorphite) in bacterial biomass, was determined by Fourier transform infrared spectroscopy and X-ray diffraction analyses. Thus, the ability of the lead-tolerant isolates to transform lead ions into stable and highly insoluble lead minerals make them potentially useful for immobilization of lead in mining waste.

  11. Experimental model of lead nephropathy

    Energy Technology Data Exchange (ETDEWEB)

    Khalil-Manesh, F.; Gonick, H.C. (Cedars-Sinai Medical Center, Los Angeles, CA (United States)); Cohen, A. (UCLA-Harbor General Hospital, Torrance, CA (United States)); Bergamaschi, E.; Mutti, A. (Univ. of Parma (Italy))

    1992-06-01

    Male Sprague-Dawley rats were exposed to high-dose (0.5%) lead acetate for periods ranging from 1 to 9 months; then lead exposure was discontinued, and animals were sacrificed after 12 months. Two additional groups of low-dose (0.01%) and high-dose (0.5%) rats were exposed to lead for 6 months, then lead was discontinued and the rats were treated with three 5-day courses of 0.5% DMSA (dimercaptosuccinic acid) over the next 6 months. Low-dose lead-treated rats showed no significant pathological changes with or without DMSA treatment, but exhibited a significant increase in GFR after DMSA. High-dose lead-treated animals showed no functional or pathological changes when lead exposure was discontinued after 1 month. However, when duration of exposure was 6 or 9 months, GFR was decreased and serum creatinine and urea nitrogen were increased as compared to controls. Tubulointerstitial disease was severe. Administration of DMSA resulted in an improvement in GFR and a decrease in albuminuria, together with a reduction in size and number of nuclear inclusion bodies in proximal tubules. However, tubulointerstitial scarring was only minimally reduced. It may be concluded that, except for brief initial exposure, discontinuation of high-dose lead exposure fails to reverse lead-induced renal damage. Treatment with the chelator, DMSA, improves renal function but has less effect on pathological alterations. As GFR improved after DMSA treatment in both low-dose and high-dose lead-treated rats, irrespective of the degree of pathological alterations, it may be concluded that the DMSA effect is most likely mediated by hemodynamic changes.

  12. Environmental lead hazard to children.

    Science.gov (United States)

    Mittal, S K

    1992-01-01

    Clinically evident lead poisoning is rare in Indian children but is more common than in adults. In children, lead poisoning may appear as fever, seizures, anemia, or abdominal pain, while in adults it is more likely to manifest as chronic minor peripheral neuropathy or gum pigmentation. Children with acute lead poisoning can be treated with chelators such as EDTA and BAL, but many are left with permanent brain damage. The most common sources of acute lead poisoning in Indian children are inhalation of fumes from burned car batteries, ingestion of flaking paint, consuming food cooked in cheap aluminum or brass utensils, and eating contaminated soil. The sources of chronic lead poisoning are water from lead pipes and fumes from industrial or automotive exhaust. Another common source in India is application of "kajjal" to children's eyes. Sources of lead in Western countries, such as drinking water, canned food, residential paint, automotive fuel, and ambient air quality, are regulated by law. None of these are regulated in India.

  13. Correlation between lead in plasma and other indicators of lead exposure among lead-exposed workers.

    Science.gov (United States)

    Hirata, M; Yoshida, T; Miyajima, K; Kosaka, H; Tabuchi, T

    1995-01-01

    In order to clarify the bioavailability of lead in plasma (PbP), we performed a study on five workers in a Japanese factory manufacturing lead glass-based paints. Blood and urine samples were obtained over a period of 15 months, during which time the workers took it in turns to perform sifting work (with the highest level of lead exposure) for 1-month periods. A total of 75 sets of blood and urine samples were thus obtained. We determined whole blood lead (PbB), PbP, Urinary coproporphyrin (CPU), urinary delta-aminolevulinic acid (ALAU), urinary lead (PbU) and ALA in plasma (ALAP). In the 15 sets of samples obtained at the end of the period with a high level of lead exposure, PbP correlated significantly with ALAU, CPU, PbU and ALAP, but PbB correlated significantly only with PbU. In the 60 sets of samples obtained following a low level of lead exposure, correlation coefficients between the concentrations of PbP and of ALAU, CPU and PbU exceeded those between the concentrations of PbB and of ALAU, CPU and PbU. These findings indicate that PbP is a better dose indicator of lead biochemically available for heme synthesis and that PbU has a closer correlation with PbP than with PbB.

  14. Ligand Synthesis Catalyst and Complex Metal Ion: Multicomponent Synthesis of 1,3-Bis(4-phenyl-[1,2,3]triazol-1-yl-propan-2-ol Copper(I Complex and Application in Copper-Catalyzed Alkyne-Azide Cycloaddition

    Directory of Open Access Journals (Sweden)

    María Teresa Ramírez-Palma

    2016-01-01

    Full Text Available A new bistriazole copper complex was synthesized by direct treatment of an alkyne, an azide, and CuI as copper salt through in situ ligand formation under a multicomponent reaction process. This complex was analyzed by XPS, TGA, DSC, and SEM techniques and revealed a triangular-shaped morphology, high thermal stability, and catalytic power in CuAAC reactions, requiring only 2.5% mol catalyst to afford 1,2,3-triazoles in good yields which can be reused at least for 4 cycles.

  15. Lead poisoning from Ayurvedic medicines.

    Science.gov (United States)

    Tsutsui, Rayji S; Van Schalkwyk, Johan; Spriggs, David

    2013-05-10

    A case of lead poisoning with established exposure to Ayurvedic medicines is presented. This patient migrated from India to New Zealand 8 years previously. He regularly visits India where he purchases "herbal remedies" for his wellbeing.

  16. Application of azides in chemoselective amidation reactions

    NARCIS (Netherlands)

    Merkx, N.S.M.

    2009-01-01

    Chemical methods that enable the synthesis and the site-selective modification of biomolecules offer great possibilities for studying their biological function and have found widespread use in chemical biology. Most often these methods employ chemoselective ligation reactions which feature mutually

  17. Lead poisoning after gunshot wound

    Directory of Open Access Journals (Sweden)

    Paulo Roberto de Madureira

    2000-05-01

    Full Text Available CONTEXT: Despite the absence of symptoms in the majority of patients carrying lead bullet fragments in their bodies, there needs to be an awareness of the possible signs and symptoms of lead intoxication when bullets are lodged in large joints like knees, hips and shoulders. Such patients merit closer follow-up, and even surgical procedure for removing the fragments. OBJECTIVE: To describe a patient who developed clinical lead intoxication several years after a gunshot wound. DESIGN: Case report. CASE REPORT: A single white 23-year-old male, regular job as a bricklayer, with a history of chronic alcohol abuse, showed up at the emergency department complaining of abdominal pain with colic, weakness, vomiting and diarrhea with black feces. All the symptoms had a duration of two to three weeks, and had been recurrent for the last two years, with calming during interval periods of two to three weeks. Abdominal radiograms showed a bullet lodged in the left hip, with a neat bursogram of the whole synovial capsule. A course of chelating treatment using calcium versenate (EDTACaNa2 intravenously was started. After the chelation therapy the patient had recurrence of his symptoms and a radical solution for the chronic mobilization of lead was considered. A hip arthroplasty procedure was performed, leading to complete substitution of the left hip.

  18. Blood lead level as biomarker of environmental lead pollution in ...

    African Journals Online (AJOL)

    Research has demonstrated a positive link between the presence of lead in freshwater, sediments or food organisms and the onset of sub-lethal effects characterized by neurological defects, kidney dysfunction, endocrine disruption, reproductive/developmental defects, behavioural abnormalities and anemia in demersal ...

  19. Lead Contamination and Microbial Lead Tolerance in Soils at Major ...

    African Journals Online (AJOL)

    Devika

    effects of combined metals (lead, zinc, copper, manganese, iron) showed that at lower concentrations, metals ... battery manufacturing operations (Atuanya et al.,. 1999; Fagade and Adetutu, 1999). This study examined ... Soil samples for analyses were air-dried, sieved through a 2mm sieve and weighed. Microbial Isolation: ...

  20. CAN FLUORIDATION AFFECT WATER LEAD LEVELS AND LEAD NEUROTOXICITY?

    Science.gov (United States)

    Recent reports have attempted to show that certain approaches to fluoridating potable water is linked to increased levels of lead(II) in the blood. We examine these claims in light of the established science and critically evaluate their significance. The completeness of nexafluo...

  1. Green primary explosives: 5-nitrotetrazolato-N2-ferrate hierarchies.

    Science.gov (United States)

    Huynh, My Hang V; Coburn, Michael D; Meyer, Thomas J; Wetzler, Modi

    2006-07-05

    The sensitive explosives used in initiating devices like primers and detonators are called primary explosives. Successful detonations of secondary explosives are accomplished by suitable sources of initiation energy that is transmitted directly from the primaries or through secondary explosive boosters. Reliable initiating mechanisms are available in numerous forms of primers and detonators depending upon the nature of the secondary explosives. The technology of initiation devices used for military and civilian purposes continues to expand owing to variations in initiating method, chemical composition, quantity, sensitivity, explosive performance, and other necessary built-in mechanisms. Although the most widely used primaries contain toxic lead azide and lead styphnate, mixtures of thermally unstable primaries, like diazodinitrophenol and tetracene, or poisonous agents, like antimony sulfide and barium nitrate, are also used. Novel environmentally friendly primary explosives are expanded here to include cat[Fe(II)(NT)(3)(H(2)O)(3)], cat(2)[Fe(II)(NT)(4)(H(2)O)(2)], cat(3)[Fe(II)(NT)(5)(H(2)O)], and cat(4)[Fe(II)(NT)(6)] with cat = cation and NT(-) = 5-nitrotetrazolato-N(2). With available alkaline, alkaline earth, and organic cations as partners, four series of 5-nitrotetrazolato-N(2)-ferrate hierarchies have been prepared that provide a plethora of green primaries with diverse initiating sensitivity and explosive performance. They hold great promise for replacing not only toxic lead primaries but also thermally unstable primaries and poisonous agents. Strategies are also described for the systematic preparation of coordination complex green primaries based on appropriate selection of ligands, metals, and synthetic procedures. These strategies allow for maximum versatility in initiating sensitivity and explosive performance while retaining properties required for green primaries.

  2. Inadvertent transarterial pacemaker lead placement

    Directory of Open Access Journals (Sweden)

    Ravi R. Bajaj

    2015-09-01

    Full Text Available We present a case of a 73-year-old patient with acute left-sided hemiparesis four months after right ventricular pacemaker insertion. Post-procedural electrocardiogram revealed a paced RBBB complex and an abnormal lead path on chest X-ray. Subsequent echocardiography and computed tomography showed left ventricular pacemaker malposition with retrograde passage to the punctured subclavian artery. We also discuss the utility of routine cardiac investigations post-insertion to identify signal lead malposition as well as management strategies once identified.

  3. OPAL 96 Blocks Lead Glass

    CERN Multimedia

    This array of 96 lead glass bricks formed part of the OPAL electromagnetic calorimeter. One half of the complete calorimeter is shown in the picture above. There were 9440 lead glass counters in the OPAL electromagnetic calorimeter. These are made of Schott type SF57 glass and each block weighs about 25 kg and consists of 76% PbO by weight. Each block has a Hamamatsu R2238 photomultiplier glued on to it. The complete detector was in the form of a cylinder 7m long and 6m in diameter. It was used to measure the energy of electrons and photons produced in LEP interactions.

  4. Chronic lead intoxication; Chronische Bleiintoxikation

    Energy Technology Data Exchange (ETDEWEB)

    Wieseler, B.; Leng, G. [Duesseldorf Univ. (Germany). Inst. fuer Hygiene; Lenz, S.; Schultz, C. [Klinikum Remscheid GmbH, Remscheid (Germany); Wilhelm, M. [Bochum Univ. (Germany). Inst. fuer Hygiene, Sozial- und Umweltmedizin

    1999-02-01

    The case of a female 68 years old patient is described. Here, a chronic lead intoxication was diagnosed after a two year old medical history with increasing attacks of colic-like abdominal pain often described as life-threatening. After repeated hospitalizations and intensive search for the cause of the symptoms, porphyria and anemia was found to be a sign of a chronic lead poisoning. The blood lead concentrations were always about a level of 600 {mu}g/L. The source of exposure could not be found by now. Neither home inspection nor environmental investigations have shown a recent source of lead intake by the patient. However, a possible occupational source of lead exposure at a blast furnace was established by anamnesis for 1952 to 1962. Thus, osteoporosis induced lead mobilisation was suspected. Noticeable are the results of the six abdominal survey radiographies taken during hospitalization within one year; three radiographies were taken following clinical admission and three before discharge of the patient. In comparison, the course shows a chronic relapsing alimentary supply from metallic particles of unknown genesis. The patient was treated with the sodium salt of 2,3-dimercapto-1-propansulfonic acid (DMPS, Dimaval{sup TM}). She was free of complain afterwards. Following therapy, the blood lead concentrations fell under a level of 400 {mu}m/L, but after several weeks the lead level raised up to the original level of 600 {mu}g/L. (orig.) [Deutsch] Es wird eine 68jaehrige Patientin vorgestellt, bei der nach fast zweijaehriger Krankengeschichte, die gekennzeichnet war durch rezidivierende, teils als lebensbedrohlich geschilderte Bauchkoliken, eine chronische Bleiintoxikation diagnostiziert wurde. Erst nach wiederholten stationaeren Krankenhausaufenthalten mit intensiver Suche nach der Krankheitsursache wurden das Krankheitsbild und die Laborwerte durch Zusatzuntersuchungen ergaenzt, so dass sich in der festgestellten Porphyrie und Anaemie die Diagnose der

  5. Registered Nurses Leading Innovative Changes

    Science.gov (United States)

    Thomas, Timothy W; Seifert, Patricia C; Joyner, Jane Clare

    2016-09-30

    As innovators, all registered nurses (RNs) act as agents of change to drive processes and policy and leverage technology to prove better, more affordable care for individuals and the community. The authors consider examples of RNs leading innovative ideas and practices to create new knowledge; develop healthcare policies and practices; improve the quality of care; and advance health information technology. This article describes a number of key innovation goals identified by the American Nurses Association Professional Issues Panel, Barriers to RN Scope of Practice, discusses relevant literature related to overcoming barriers to innovation, and identifies recommendations for leading innovative change to achieve innovation goals.

  6. Leading in a Technological Age

    Science.gov (United States)

    Yadgir, Sheri A.

    2011-01-01

    Technology is advancing more rapidly than at any time in history since the beginning of the Industrial Revolution. In fact, experts say that the world is leaving the Industrial Age of the 20th century and entering an Information Age that will lead into the future. These advances mean that important changes are being made in all areas of life--and…

  7. OPAL Various Lead Glass Blocks

    CERN Multimedia

    These lead glass blocks were part of a CERN detector called OPAL (one of the four experiments at the LEP particle detector). OPAL uses some 12 000 blocks of glass like this to measure particle energies in the electromagnetic calorimeter. This detector measured the energy deposited when electrons and photons were slowed down and stopped.

  8. Blood Lead and Reading Readiness

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap

    2013-08-01

    Full Text Available Investigators at the University of Maryland School of Nursing, Johns Hopkins School of Public Health, and Department of Health, Providence, Rhode Island, evaluated the relationship between reading readiness test scores for children attending public kindergarten in Providence, RI, and state health department records of blood lead levels (BLLs.

  9. Developments in lead-acid batteries: a lead producer's perspective

    Science.gov (United States)

    Frost, P. C.

    Rapid progress is being made in many aspects of materials, design and construction for lead-acid batteries. Much of this work has taken place under the auspices of the Advanced Lead-Acid Battery Consortium (ALABC). From the general tone of the literature, it seems likely that several of these developments will be adopted in commercial products, and that there will be cross-fertilization between the emerging electric vehicle (EV) battery technology and the starting, lighting and ignition (SLI) battery. Given the impetus for improvement from several different factors, the development process appears to be accelerating. To those not intimately involved in the battery design and specification process, it is not clear which of the possible developments will make it from the laboratory to general commercial adoption. Some of the possible changes in materials, design and construction could have an impact on the recovery, recycling, smelting and refining of lead-acid batteries. Some of the possible developments are outlined and their possible impact is discussed. It is likely that negative effects may be minimized if battery developments are considered from other perspectives, largely based on the overall life-cycle, as early in the design phase of new products as possible. Three strategies for minimizing undesirable effects are advocated: first, improved communication between car manufacturers, battery manufacturers and lead producers second, use of life-cycle analysis (LCA) to identify and optimize all attributes of the product throughout its life-cycle third, concerted and coordinated action to deal with issues important to the industry once trends are identified.

  10. Lead-antimony alloys for electrode supports for lead accumulators

    Energy Technology Data Exchange (ETDEWEB)

    Dalibard, G.; Viaud, N.

    1984-04-17

    The grain size and resistance to corrosion of lead-antimony alloys containing less than 4% of antimony and 0.005 to 0.1% copper, are improved by incorporating therein from 0.001 to 0.1% of a mixture of rare earths, preferably misch metal. The alloys may also contain up to 0.5% arsenic or up to 0.8% of tin.

  11. Lead and Drinking Water from Private Wells

    Science.gov (United States)

    ... type=”submit” value=”Submit” /> Healthy Water Home Lead and Drinking Water from Private Wells Recommend on ... remove lead from my drinking water? What is lead? Lead is a naturally occurring bluish-gray metal ...

  12. Deformation properties of lead isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Tolokonnikov, S. V.; Borzov, I. N.; Lutostansky, Yu. S.; Saperstein, E. E., E-mail: saper43-7@mail.ru [National Research Center Kurchatov Institute (Russian Federation)

    2016-01-15

    The deformation properties of a long lead isotopic chain up to the neutron drip line are analyzed on the basis of the energy density functional (EDF) in the FaNDF{sup 0} Fayans form. The question of whether the ground state of neutron-deficient lead isotopes can have a stable deformation is studied in detail. The prediction of this deformation is contained in the results obtained on the basis of the HFB-17 and HFB-27 Skyrme EDF versions and reported on Internet. The present analysis reveals that this is at odds with experimental data on charge radii and magnetic moments of odd lead isotopes. The Fayans EDF version predicts a spherical ground state for all light lead isotopes, but some of them (for example, {sup 180}Pb and {sup 184}Pb) prove to be very soft—that is, close to the point of a phase transition to a deformed state. Also, the results obtained in our present study are compared with the predictions of some other Skyrme EDF versions, including SKM*, SLy4, SLy6, and UNE1. By and large, their predictions are closer to the results arising upon the application of the Fayans functional. For example, the SLy4 functional predicts, in just the same way as the FaNDF{sup 0} functional, a spherical shape for all nuclei of this region. The remaining three Skyrme EDF versions lead to a deformation of some light lead isotopes, but their number is substantially smaller than that in the case of the HFB-17 and HFB-27 functionals. Moreover, the respective deformation energy is substantially lower, which gives grounds to hope for the restoration of a spherical shape upon going beyond the mean-field approximation, which we use here. Also, the deformation properties of neutron-rich lead isotopes are studied up to the neutron drip line. Here, the results obtained with the FaNDF{sup 0} functional are compared with the predictions of the HFB-17, HFB-27, SKM*, and SLy4 Skyrme EDF versions. All of the EDF versions considered here predict the existence of a region where neutron

  13. Leading Hadron Production at HERA

    Directory of Open Access Journals (Sweden)

    Buniatyan Armen

    2013-06-01

    Full Text Available Data from the recent measurements of very forward baryon and photon production with the H1 and ZEUS detectors at electron-proton collider HERA are presented and compared to the theoretical calculations and Monte Carlo models. Results are presented of the production of leading protons, neutrons and photons in deep inelastic scattering (ep → e' pX, ep → e'nX, ep → e'γX as well as the leading neutron production in the photoproduction of dijets (ep → ejjXn. The forward baryon and photon results from the H1 and ZEUS Experiments are compared also with the models of the hadronic interactions of high energy Cosmic Rays. The sensitivity of the HERA data to the differences between the models is demonstrated.

  14. Anthropogenic lead isotopes in Antarctica

    Energy Technology Data Exchange (ETDEWEB)

    Rosman, K.J.R.; Chisholm, W. [Curtin Univ. of Technology, Bentley (Australia); Boutron, C.F. [Laboratoire de Glaciologie et Geophysique de l`Environnement du CNRS, St. Martin d`Heres (France)]|[Domaine Universitaire, Grenoble (France); Candelone, J.P. [Laboratoire de Glaciologie et Geophysique de l`Environnement du CNRS, St. Martin d`Heres (France); Patterson, C.C. [California Institute of Technology, Pasadena, CA (United States)

    1994-12-01

    The authors present results from the first Pb isotopic study of the sources of lead in snow samples from the Antarctic. Samples of recent snow fields were compared with measurements of samples taken from deep cores, and they reveal that recent snows show pronounced influence of anthropogenic sources. These results are independent of geochemical arguments based on influences of Al, Na, or SO{sub 4}.

  15. How to lead complex situations

    DEFF Research Database (Denmark)

    Hansen, Michael Pingel

    2013-01-01

    The military leader is experiencing increasingly more complex situations, whether it is as leader in a foreign combat environment or in the home-based public administration. Complex situations like these call for a special set of managerial responses and a special way of leading organisations....... The proposition of this article is that the methods that drive innovative processes, strengthening the creative culture, are necessary to manage complex situations in military contexts....

  16. Picornavirus infection leading to immunosuppression

    OpenAIRE

    Cusick, Matthew F; Libbey, Jane E.; Fujinami, Robert S.

    2014-01-01

    Viruses, such as HIV, hepatitis A, poliovirus, coxsackievirus B3 and foot-and-mouth disease virus, use a variety of mechanisms to suppress the human immune system in order to evade clearance by the host. Therefore, investigating how a few changes in the viral genome of a nonlethal virus can lead to an alteration in disease, from survivable to immunosuppression and death, would provide valuable information into viral pathogenesis. In addition, we propose that gaining a better insight into how ...

  17. Leading Indian Business-Groups

    Directory of Open Access Journals (Sweden)

    Maria Alexandrovna Vorobyeva

    2016-01-01

    Full Text Available The goal of this paper is to investigate the evolution of the leading Indian business-groups under the conditions of economical liberalization. It is shown that the role of modern business-groups in the Indian economy is determined by their high rate in the gross domestic product (GDP, huge overall actives, substantial pert in the e[port of goods and services, as well as by their activities in modern branch structure formatting, and developing labor-intensive and high-tech branches. They strongly influence upon economical national strategies, they became a locomotive of internationalization and of transnationalization of India, the basis of the external economy factor system, the promoters of Indian "economical miracle" on the world scene, and the dynamical segment of economical and social development of modern India. The tendencies of the development of the leading Indian business groups are: gradual concentration of production in few clue sectors, "horizontal" structure, incorporation of the enterprises into joint-stock structure, attraction of hired top-managers and transnationaliziation. But against this background the leading Indian business-groups keep main traditional peculiarities: they mostly still belong to the families of their founders, even today they observe caste or communal relations which are the basis of their non-formal backbone tides, they still remain highly diversificated structures with weak interrelations. Specific national ambivalence and combination of traditions and innovations of the leading Indian business-groups provide their high vitality and stability in the controversial, multiform, overloaded with caste and confessional remains Indian reality. We conclude that in contrast to the dominant opinion transformation of these groups into multisectoral corporations of the western type is far from completion, and in the nearest perspective they will still possess all their peculiarities and incident social and economical

  18. The LHC Lead Injector Chain

    CERN Document Server

    Beuret, A; Blas, A; Burkhardt, H; Carli, Christian; Chanel, M; Fowler, A; Gourber-Pace, M; Hancock, S; Hourican, M; Hill, C E; Jowett, John M; Kahle, K; Küchler, D; Lombardi, A M; Mahner, E; Manglunki, Django; Martini, M; Maury, S; Pedersen, F; Raich, U; Rossi, C; Royer, J P; Schindl, Karlheinz; Scrivens, R; Sermeus, L; Shaposhnikova, Elena; Tranquille, G; Vretenar, Maurizio; Zickler, T

    2004-01-01

    A sizeable part of the LHC physics programme foresees lead-lead collisions with a design luminosity of 1027 cm-2 s-1. This will be achieved after an upgrade of the ion injector chain comprising Linac3, LEIR, PS and SPS machines [1,2]. Each LHC ring will be filled in 10 min by almost 600 bunches, each of 7×107 lead ions. Central to the scheme is the Low Energy Ion Ring (LEIR) [3,4], which transforms long pulses from Linac3 into high-brilliance bunches by means of multi-turn injection, electron cooling and accumulation. Major limitations along the chain, including space charge, intrabeam scattering, vacuum issues and emittance preservation are highlighted. The conversion from LEAR (Low Energy Antiproton Ring) to LEIR involves new magnets and power converters, high-current electron cooling, broadband RF cavities, and a UHV vacuum system with getter (NEG) coatings to achieve a few 10-12 mbar. Major hardware changes in Linac3 and the PS are also covered. An early ion scheme with fewer bunches (but each at nominal...

  19. Relational Leading and Dialogic Process

    DEFF Research Database (Denmark)

    Hansen, Lone Hersted

    The Ph.D. thesis contributes to a relational orientation to leading, emphasizing leadership as a shared, collaborative and co-creative activity. In this paradigm major emphasis is put on dialogue and interaction. Inspired by social constructionist ideas, the thesis considers approaches to learning...... with the thesis, dialogically based practices inspired by action research with the aim to enhance collaborative knowledge building, reflexivity and dialogical skills in groups and teams were carried out, analyzed and documented. Participants included school principals, leaders of kindergartens, teachers...

  20. Lead-nickel electrochemical batteries

    CERN Document Server

    Glaize, Christian

    2012-01-01

    The lead-acid accumulator was introduced in the middle of the 19th Century, the diverse variants of nickel accumulators between the beginning and the end of the 20th Century. Although old, these technologies are always very present on numerous markets. Unfortunately they are still not used in optimal conditions, often because of the misunderstanding of the internal electrochemical phenomena.This book will show that batteries are complex systems, made commercially available thanks to considerable amounts of scientific research, empiricism and practical knowledge. However, the design of

  1. Elevation leads to altruistic behavior.

    Science.gov (United States)

    Schnall, Simone; Roper, Jean; Fessler, Daniel M T

    2010-03-01

    Feelings of elevation, elicited by witnessing another person perform a good deed, have been hypothesized to motivate a desire to help others. However, despite growing interest in the determinants of prosocial behavior, there is only limited evidence that elevation leads to increases in altruistic behavior. In two experiments, we tested the relationship between elevation and helping behavior. Prior to measuring helping behavior, we measured elevation among participants in an elevation-inducing condition and control conditions in order to determine whether witnessing altruistic behavior elicited elevation. In Experiment 1, participants experiencing elevation were more likely to volunteer for a subsequent unpaid study than were participants in a neutral state. In Experiment 2, participants experiencing elevation spent approximately twice as long helping the experimenter with a tedious task as participants experiencing mirth or a neutral emotional state. Further, feelings of elevation, but not feelings of amusement or happiness, predicted the amount of helping. Together, these results provide evidence that witnessing another person's altruistic behavior elicits elevation, a discrete emotion that, in turn, leads to tangible increases in altruism.

  2. All roads lead to Meyrin

    CERN Multimedia

    Communication locale

    2011-01-01

    Tous les chemins mènent à Meyrin - All roads lead to Meyrin From 29 September to 16 October, 2011, come to the Salle Antoine Verchère in Meyrin for Tous les chemins mènent à Meyrin. The celebration will include an exposition as well as a theatrical performance about Meyrin, the first satellite city in Switzerland. With the help of the memories and testimonies from the people of Meyrin, Tous les chemins mènent à Meyrin is putting the collective memories of the commune on display. It is an occasion for everyone, whether you're from near or far, to find out how all the roads lead to Meyrin.  Salle Antoine-Verchère Route de Meyrin 294 – 1217 Meyrin Tram 18 – Stop: Meyrin Village Thursdays / Fridays / Saturdays at 8pm Sundays at 5pm Regular ticket: CHF 15.- Concession ticket (students, chômeurs, AVS, AI): CHF 12.- Children up to 16: CHF 10.- Family ticket: CHF 35.-

  3. Helping Parents Prevent Lead Poisoning. ERIC Digest.

    Science.gov (United States)

    Binns, Helen J.; Ricks, Omar Benton

    Children are at greater risk than adults for lead poisoning because children absorb lead more readily than adults, and a small amount of lead in children's bodies can do a great deal of harm. Some of the causes and effects of childhood lead poisoning and suggests some lead poisoning prevention strategies that parent educators can share with…

  4. Anti-cancer Lead Molecule

    KAUST Repository

    Sagar, Sunil

    2014-04-17

    Derivatives of plumbagin can be selectively cytotoxic to breast cancer cells. Derivative `A` (Acetyl Plumbagin) has emerged as a lead molecule for testing against estrogen positive breast cancer and has shown low hepatotoxicity as well as overall lower toxicity in nude mice model. The toxicity of derivative `A` was determined to be even lower than vehicle control (ALT and AST markers). The possible mechanism of action identified based on the microarray experiments and pathway mapping shows that derivative `A` could be acting by altering the cholesterol-related mechanisms. The low toxicity profile of derivative `A` highlights its possible role as future anti-cancer drug and/or as an adjuvant drug to reduce the toxicity of highly toxic chemotherapeutic drugs

  5. Multi-lead heat sink

    Science.gov (United States)

    Roose, Lars D.

    1984-01-01

    The disclosure relates to a heat sink used to protect integrated circuits from the heat resulting from soldering them to circuit boards. A tubular housing contains a slidable member which engages somewhat inwardly extending connecting rods, each of which is rotatably attached at one end to the bottom of the housing. The other end of each rod is fastened to an expandable coil spring loop. As the member is pushed downward in the housing, its bottom edge engages and forces outward the connecting rods, thereby expanding the spring so that it will fit over an integrated circuit. After the device is in place, the member is slid upward and the spring contracts about the leads of the integrated circuit. Soldering is now conducted and the spring absorbs excess heat therefrom to protect the integrated circuit. The placement steps are repeated in reverse order to remove the heat sink for use again.

  6. Lead-Based Paint and Demolition

    Science.gov (United States)

    The Lead Renovation, Repair, and Painting Rule does not apply to total demolition of a structure. Learn about EPA recommended lead-safe practices during total demolition activities to prevent and minimize exposure to lead.

  7. [XANES study of lead speciation in duckweed].

    Science.gov (United States)

    Chu, Bin-Bin; Luo, Li-Qiang; Xu, Tao; Yuan, Jing; Sun, Jian-Ling; Zeng, Yuan; Ma, Yan-Hong; Yi, Shan

    2012-07-01

    Qixiashan lead-zinc mine of Nanjing was one of the largest lead zinc deposits in East China Its exploitation has been over 50 years, and the environmental pollution has also been increasing. The lead concentration in the local environment was high, but lead migration and toxic mechanism has not been clear. Therefore, biogeochemistry research of the lead zinc mine was carried out. Using ICP-MS and Pb-L III edge XANES, lead concentration and speciation were analyzed respectively, and duckweed which can tolerate and enriched heavy metals was found in the pollution area. The results showed that the lead concentration of duckweed was 39.4 mg x kg(-1). XANES analysis and linear combination fit indicated that lead stearate and lead sulfide accounted for 65% and 36.9% respectively in the lead speciation of duckweed, suggesting that the main lead speciation of duckweed was sulfur-containing lead-organic acid.

  8. Basic Information about Lead in Drinking Water

    Science.gov (United States)

    ... Health) Lead can also be transmitted through breast milk. Read more on lead exposure in pregnancy and lactating women (PDF) (302 pp, 4.3 MB, About PDF ) . Adults Lead is also harmful to adults. Adults exposed ...

  9. The identification of lead ammunition as a source of lead exposure in First Nations: The use of lead isotope ratios

    Energy Technology Data Exchange (ETDEWEB)

    Tsuji, Leonard J.S. [Department of Environment and Resource Studies, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada)], E-mail: ljtsuji@fes.uwaterloo.ca; Wainman, Bruce C. [Faculty of Health Sciences, McMaster University, Hamilton, Ontario, L8N 3Z5 (Canada); Martin, Ian D. [Department of Environment and Resource Studies, University of Waterloo, Waterloo, Ontario, N2L 3G1 (Canada); Sutherland, Celine [Attawapiskat First Nation Health Services, Attawapiskat, Ontario, P0L 1A0 (Canada); Weber, Jean-Philippe; Dumas, Pierre [Centre de toxicologie, Institut national de sante publique du Quebec, Quebec City, Quebec, G1V 5B3 (Canada); Nieboer, Evert [Faculty of Health Sciences, McMaster University, Hamilton, Ontario, L8N 3Z5 (Canada); Institute of Community Medicine, University of Tromso, Tromso N-9037 (Norway)

    2008-04-15

    The use of lead shotshell to hunt water birds has been associated with lead-contamination in game meat. However, evidence illustrating that lead shotshell is a source of lead exposure in subsistence hunting groups cannot be deemed definitive. This study seeks to determine whether lead shotshell constitutes a source of lead exposure using lead isotope ratios. We examined stable lead isotope ratios for lichens, lead shotshell and bullets, and blood from residents of Fort Albany and Kashechewan First Nations, and the City of Hamilton, Ontario, Canada. Data were analyzed using ANOVA and regression analyses. ANOVA of isotope ratios for blood revealed significant differences with respect to location, but not sex. Hamilton differed from both Kashechewan and Fort Albany; however, the First Nations did not differ from each other. ANOVA of the isotope ratios for lead ammunition and lichens revealed no significant differences between lichen groups (north and south) and for the lead ammunition sources (pellets and bullets). A plot of {sup 206}Pb/{sup 204}Pb and {sup 206}Pb/{sup 207}Pb values illustrated that lichens and lead ammunition were distinct groupings and only the 95% confidence ellipse of the First Nations group overlapped that of lead ammunition. In addition, partial correlations between blood-lead levels (adjusted for age) and isotope ratios revealed significant (p < 0.05) positive correlations for {sup 206}Pb/{sup 204}Pb and {sup 206}Pb/{sup 207}Pb, and a significant negative correlation for {sup 208}Pb/{sup 206}Pb, as predicted if leaded ammunition were the source of lead exposure. In conclusion, lead ammunition was identified as a source of lead exposure for First Nations people; however, the isotope ratios for lead shotshell pellets and bullets were indistinguishable. Thus, lead-contaminated meat from game harvested with lead bullets may also be contributing to the lead body burden.

  10. Association of Lead Levels and Cerebral Palsy

    OpenAIRE

    Neha Bansal MD; Anju Aggarwal MD, FIAP, MNAMS; M. M. A. Faridi MD, FIAP, MNAMS; Tusha Sharma PhD; B. D. Baneerjee PhD

    2017-01-01

    Background: Cerebral palsy is a common motor disability in childhood. Raised lead levels affect cognition. Children with cerebral palsy may have raised lead levels, further impairing their residual cognitive motor and behavioral abilities. Environmental exposure and abnormal eating habits may lead to increased lead levels. Aims and Objectives: To measure blood lead levels in children with cerebral palsy and compare them with healthy neurologically normal children. To correlate blood lead leve...

  11. Evaluation and management of lead exposure

    OpenAIRE

    Kim, Hwan-Cheol; Jang, Tae-Won; Chae, Hong-Jae; Choi, Won-Jun; Ha, Mi-Na; Ye, Byeong-Jin; Kim, Byoung-Gwon; Jeon, Man-Joong; Kim, Se-yeong; Hong, Young-Seoub

    2015-01-01

    Lead, which is widely used in industry, is a common element found in low concentrations in the Earth?s crust. Implementations to reduce environmental lead concentrations have resulted in a considerable reduction of lead levels in the environment (air) and a sustained reduction in the blood lead levels of the average citizen. However, people are still being exposed to lead through a variety of routes in everyday commodities. Lead causes health problems such as toxicity of the liver, kidneys, h...

  12. Blood lead levels and cumulative blood lead index (CBLI) as predictors of late neurodevelopment in lead poisoned children

    Science.gov (United States)

    Nie, Linda H.; Wright, Robert O.; Bellinger, David C.; Hussain, Javed; Amarasiriwardena, Chitra; Chettle, David R.; Pejović-Milić, Ana; woolf, Alan; Shannon, Michael

    2011-01-01

    Objective To find the best lead exposure assessment marker for children. Methods We recruited 11 children, calculated a cumulative blood lead index (CBLI) for the children, measured their concurrent BLL, assessed their development, and measured their bone lead level. Results Nine of 11 children had clinically significant neurodevelopment problems. CBLI and current blood lead level, but not the peak lead level, were significantly or marginally negatively associated with the full-scale IQ score. Conclusion Lead exposure at younger age significantly impacts a child’s later neurodevelopment. CBLI may be a better predictor of neurodevelopment than are current or peak blood lead levels. PMID:21827276

  13. Darwinian selection leads to Gaia.

    Science.gov (United States)

    Staley, Mark

    2002-09-07

    The Gaia hypothesis, in its strongest form, states that the Earth's atmosphere, oceans, and biota form a tightly coupled system that maintains environmental conditions close to optimal for life. According to Gaia theory, optimal conditions are intrinsic, immutable properties of living organisms. It is assumed that the role of Darwinian selection is to favor organisms that act to stabilize environmental conditions at these optimal levels. In this paper, an alternative form of Gaia theory based on more traditional Darwinian principles is proposed. In the new approach, environmental regulation is a consequence of population dynamics, not Darwinian selection. The role of selection is to favor organisms that are best adapted to prevailing environmental conditions. However, the environment is not a static backdrop for evolution, but is heavily influenced by the presence of living organisms. The resulting co-evolving dynamical process eventually leads to the convergence of equilibrium and optimal conditions. A simple Daisyworld model is used to illustrate this convergence phenomenon. Sensitivity analysis of the Daisyworld model suggests that in stable ecosystems, the convergence of equilibrium and optimal conditions is inevitable, provided there are no externally driven shocks to the system. The end result may appear to be the product of a cooperative venture, but is in fact the outcome of Darwinian selection acting upon "selfish" organisms.

  14. Leading local politicians visit CERN

    CERN Multimedia

    2001-01-01

    Left to right:  Professor Maiani, Ernest Nycollin, Anne-Marie Comparini, and Jean Pépin surrounded by young PRAC. On the 13th of November leading local politicians : Mme Anne-Marie Comparini, Présidente du Conseil régional de Rhône-Alpes, M. Ernest Nycollin, Président du Conseil général de la Haute-Savoie et M. Jean Pépin, Président du Conseil général de l'Ain took part in a ceremony which featured the insertion of one of the first LHC magnets into its cryostat.  The department of l'Ain financed a large part of the contruction of building SMA 18 which will see intense activity during the assembly of LHC magnets over the next four years. The department of Haute-Savoie helped in the development of the ultrasonic welding machine for the superconducting cables and the conception of integrated circuits that will be used to measure temperature and pressure inside the magnets. T...

  15. Dietary exposure to lead in the Netherlands

    NARCIS (Netherlands)

    Boon PE; te Biesebeek JD; van Donkersgoed G; VVH; V&Z

    2017-01-01

    Uptake from the soil is the main route by which lead ends up in food. Lead in soil has its origin in both natural and anthropogenic sources. The lead concentration in food has decreased over the last decennia by the use of unleaded petrol and paint, and the replacement of lead water pipes.

  16. Lead Poisoning: A Need for Education.

    Science.gov (United States)

    Lipnickey, Susan Cross

    1981-01-01

    Each year approximately 200 children die of lead poisoning. Especially vulnerable to the toxic effects of lead poisoning are the nervous system, kidneys, and the bones. Physiological effects of lead on the school-age child, screening processes, and roles of school personnel in dealing with suspected victims of lead poisoning are discussed. (JN)

  17. Sodium Azide Associated Acute Hyperkalemia in a Swine Model of Sodium Azide Toxicity

    Science.gov (United States)

    2017-06-16

    Surgical Center (WHASC) internship and residency programs. 3. Please know that if you are a Graduate Health Sciences Education student and your...Continued Graph 1. Potassium trends over time In treated vs. non treated animals Limitations ....•..• Potil1isium r Conclusions r--.J" ..J’--J’-...j...J.’-.J’,J, ....~,..J,j\\""r--’-i~-....f’.J’ J I , .a- ,.... _ ••••••••1 _ •.•••••• J _ •• ~ zo_ 110_ __ W_ fO$ Figure 1. ST elevation In animal #8611

  18. catena-Poly[[(1,10-phenanthroline-κ2N,N′lead(II]-μ-azido-κ2N1:N3-μ-nitrito-κ3O,O′:O′-[(1,10-phenanthroline-κ2N,N′lead(II]-di-μ-azido-κ4N1:N1

    Directory of Open Access Journals (Sweden)

    Gholamhossein Mohammadnezhad

    2010-07-01

    Full Text Available The title coordination polymer, [Pb2(N33(NO2(C12H8N22]n, has as the repeat unit a centrosymmetric dinuclear molecule having azide and nitrite groups that bridge adjacent heterocycle-coordinated metal centers. One of the azide group uses its terminal ends to bridge whereas the nitrite group chelates to one metal atom and uses one of its O atoms to bridge. The azide and nitrite groups are disordered with respect to each other in a 1:1 ratio. Adjacent dinuclear molecules are further bridged by the other two azide groups, generating a linear chain motif parallel to [010]. Half of the Pb atoms show a Ψ-dodecahedral coordination and the other half show a Ψ-pentagonal-bipyramidal coordination.

  19. Lead poisoning in captive wild animals

    Energy Technology Data Exchange (ETDEWEB)

    Zook, B.C.; Sauer, R.M.; Garner, F.M.

    1972-07-01

    Lead poisoning was diagnosed post-mortem in 34 simian primates, 11 parrots, and 3 Australian fruit bats at the National Zoological Park. Diagnoses were made by the finding of acid-fast intranuclear inclusion bodies in renal epithelia or hepatocytes and, in most cases, by finding excess lead in samples of liver. The estimated prevalence of lead intoxication among autopsied primates and parrots was 44% and 50% respectively. Leaded paint was found in many animal enclosures at this zoo and it was available to all the lead-poisoned animals in this study. The finding of renal intranuclear inclusion bodies in animals at several zoos, scattered reports of lead intoxication of animals dwelling in various zoos, the occurrence of leaded paint in many zoos and the high incidence of lead poisoning at this zoo, indicated that lead poisoning of zoo animals is much more common than was previously thought.

  20. Leading gravitational corrections and a unified universe

    DEFF Research Database (Denmark)

    Codello, Alessandro; Jain, Rajeev Kumar

    2016-01-01

    Leading order gravitational corrections to the Einstein-Hilbert action can lead to a consistent picture of the universe by unifying the epochs of inflation and dark energy in a single framework. While the leading local correction induces an inflationary phase in the early universe, the leading...... nonlocal term leads to an accelerated expansion of the universe at the present epoch. We argue that both the leading UV and IR terms can be obtained within the framework of a covariant effective field theory of gravity. The perturbative gravitational corrections therefore provide a fundamental basis...

  1. Lead poisoning in children: a case report.

    Science.gov (United States)

    Jouhadi, Zineb; Bensabbahia, Dalal; Chafiq, Fouad; Oukkache, Bouchra; Guebessi, Nisrine Bennani; Abdellah, El Abidi; Najib, Jilali

    2016-01-01

    Lead colic is a rare cause of abdominal pain. The diagnosis of lead poisoning is most often mentioned in at risk populations (children, psychotic). We report the case of a 2 year old child that was presented for acute abdomen. Abdominal plain radiograph showed multiple intra-colonic metallic particles and suggested lead poisoning diagnosis. Anamnesis found a notion of pica and consumption of peeling paint. Elevated blood lead levels (BLL) confirmed the diagnosis. The lead poisoning is a public health problem especially in children, but its manifestation by a lead colic is rare and could simulate an acute abdomen table.

  2. Clinical utility of computed electrocardiographic leads.

    Science.gov (United States)

    Batchvarov, Velislav N; Behr, Elijah R

    2014-01-01

    The standard 12-lead electrocardiogram (ECG) is only one of the possible ways to present the voltage differences between the nine recording electrodes. Other "non-conventional" leads may be constructed by physically connecting two or more electrodes in a different manner or by computation from the digital 12-lead ECG. Examples include bipolar or multipolar precordial leads and bipolar chest leads (between one precordial and one limb electrode). Such leads can remove or decrease noise originating from a limb cable/electrode that is present in the unipolar precordial leads. They can be diagnostically useful in Brugada syndrome and can display QRS fractionation that is not visible in the respective unipolar precordial or limb leads. Multipolar precordial leads sometimes display potentially useful information that is not visible in the respective unipolar leads and in bipolar leads computed from them. In conclusion, these computed ECG leads represent a potentially useful supplement to the conventional 12-lead ECG. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Lead Smelting and Refining at Kosaka Smelter

    National Research Council Canada - National Science Library

    MITSUNE, Yutaka; SATOH, Shigeki

    2007-01-01

      Kosaka Smelting and Refining Co., Ltd. operates lead smelting to produce electrolytic lead and to recover precious metals and bismuth with mainly secondary materials from copper smelter and zinc refinery...

  4. Some Lead Poisoning Tests May Be Faulty

    Science.gov (United States)

    ... https://medlineplus.gov/news/fullstory_165668.html Some Lead Poisoning Tests May Be Faulty But the majority of ... More Health News on Children's Health Laboratory Tests Lead Poisoning Recent Health News Related MedlinePlus Health Topics Children's ...

  5. Lead Poisoning in Remodeling of Old Homes

    Science.gov (United States)

    Barnes, Bart

    1973-01-01

    An article based on Dr. Muriel D. Wolf's study of elevated blood lead levels in children and adults present during the remodeling of old homes. Lead poisoning examples, symptoms, and precautions are given. (ST)

  6. WETTABILITY STUDIES OF LEAD-FREE SOLDERS

    African Journals Online (AJOL)

    2012-03-01

    Mar 1, 2012 ... language and behavioural problems [3]. Pregnant women and young children are particularly vul- nerable to lead ... However, this is controlled by a combination of several factors .... placement of tin-lead solders. Contact ...

  7. A Public Health Approach to Addressing Lead

    Science.gov (United States)

    Describes EPA’s achievements in reducing childhood lead exposures and emphasizes the need to continue actions to further reduce lead exposures, especially in those communities where exposures remain high.

  8. Observations on lead pollution in milk

    Energy Technology Data Exchange (ETDEWEB)

    Maffeo, G.; Renon, P.

    1976-08-01

    The problem of lead pollution in milk in highly industrialized areas (district of Milan) has been evaluated. Potentially dangerous rates of lead have been checked in milk, agricultural fields, fodders and entrails of slaughtered animals.

  9. Leading Change: Military Leadership in Civilian Organizations

    Science.gov (United States)

    2012-03-19

    lead to a very frustrating stalemate for both the military leader and the organization they join. LEADING CHANGE: MILITARY LEADERSHIP IN...Civilian adds, “For the military leader , managing a civilian workforce is different from leading military subordinates.”4 Military members must...must plot a course to get the organization on the right path. Finally, the leader must lead and manage change in their organization while keeping

  10. Lead exposure from aluminum cookware in Cameroon

    Energy Technology Data Exchange (ETDEWEB)

    Weidenhamer, Jeffrey D.; Kobunski, Peter A. [Department of Chemistry, Geology and Physics, 401 College Ave., Ashland University, Ashland, OH 44805 (United States); Kuepouo, Gilbert [Research and Education Centre for Development (CREPD), Yaounde (Cameroon); Corbin, Rebecca W. [Department of Chemistry, Geology and Physics, 401 College Ave., Ashland University, Ashland, OH 44805 (United States); Gottesfeld, Perry, E-mail: pgottesfeld@okinternational.org [Occupational Knowledge International, San Francisco, CA (United States)

    2014-10-15

    Blood lead levels have decreased following the removal of lead from gasoline in most of the world. However, numerous recent studies provide evidence that elevated blood lead levels persist in many low and middle-income countries around the world at much higher prevalence than in the more developed countries. One potential source of lead exposure that has not been widely investigated is the leaching of lead from artisanal aluminum cookware, which is commonly used in the developing world. Twenty-nine samples of aluminum cookware and utensils manufactured by local artisans in Cameroon were collected and analyzed for their potential to release lead during cooking. Source materials for this cookware included scrap metal such as engine parts, radiators, cans, and construction materials. The lead content of this cookware is relatively low (< 1000 ppm by X-ray fluorescence), however significant amounts of lead, as well as aluminum and cadmium were released from many of the samples using dilute acetic acid extractions at boiling and ambient temperatures. Potential exposures to lead per serving were estimated to be as high as 260 μg, indicating that such cookware can pose a serious health hazard. We conclude that lead, aluminum and cadmium can migrate from this aluminum cookware during cooking and enter food at levels exceeding recommended public health guidelines. Our results support the need to regulate lead content of materials used to manufacture these pots. Artisanal aluminum cookware may be a major contributor to lead poisoning throughout the developing world. Testing of aluminum cookware in other developing countries is warranted. - Highlights: • Cookware is manufactured in Cameroon from scrap aluminum including car parts. • Twenty-nine cookware samples were evaluated for their potential to leach lead. • Boiling extractions to simulate the effects of cooking released significant lead. • Potential lead exposures per serving are estimated as high as 260 μg.

  11. Developmental Effects of Lead Exposure in Children.

    Science.gov (United States)

    Tesman, Johanna Rich; Hills, Amanda

    1994-01-01

    This report presents an overview of research on childhood lead exposure and poisoning, and the related social issues. The report first summarizes the history of lead poisoning and its prevalence in the United States, and discusses the basis for recent changes in guidelines for lead exposure by the Centers for Disease Control (CDC). The report then…

  12. Hematological evaluation of lead intoxication in mallards

    Energy Technology Data Exchange (ETDEWEB)

    Mautino, M.; Bell, J.U.

    1987-01-01

    The measurement of blood lead has been the most widely accepted laboratory test for monitoring environmental lead exposure. Many technical difficulties are inherent in the precise quantification of blood lead at low concentrations and a margin of error of fifteen percent is not uncommon. Measurement of critical biochemical alterations resulting from lead exposure may provide a better indication of the toxic response of an individual than the actual measurement of blood lead. Lead exposure alters a number of enzymes resulting in impaired heme synthesis and an elevation or excretion of intermediates. Although the determination of blood lead has been the reference standard for monitoring lead exposure, the measurement of delta-aminolevulinic acid dehydratase activity (delta-ALAD) and free erythrocyte protoporphyrin concentrations (FEP) have been utilized to evaluate the extent of lead exposure in several species. In humans, there is a good correlation between both delta-ALAD and FEP and the deleterious effects seen following lead exposure. In avian species, investigators have measured elevated lead concentrations and an inhibition of delta-ALAD activity in lead-dosed mallards.

  13. Is Your Child Safe from Lead Poisoning?

    Centers for Disease Control (CDC) Podcasts

    2008-10-02

    In this podcast, Dr. Mary Jean Brown, chief of CDC's Lead Poisoning and Prevention Program, discusses the importance of testing children for lead poisoning, who should be tested, and what parents can do to prevent lead poisoning.  Created: 10/2/2008 by National Center for Environmental Health (NCEH).   Date Released: 10/2/2008.

  14. WETTABILITY STUDIES OF LEAD-FREE SOLDERS

    African Journals Online (AJOL)

    2012-03-01

    Mar 1, 2012 ... wettability, solder, lead, alloy, tin. 1. Introduction. Tin-lead solder has been the standard mate- rial used in electronic, chemical, automotive and other industries due to its low cost and unique material properties like low melting point, avail- ability etc. However, the toxicity of lead during industrial production of ...

  15. Lead poisoning of a marbled godwit

    Science.gov (United States)

    Locke, L.N.; Smith, M.R.; Windingstad, R.M.; Martin, S.J.

    1991-01-01

    A thin adult female marbled godwit (Limosa fedoa) found dead at Benton Lake National Wildlife Refuge, Montana, was found to have 17 ingested lead shot in its gizzard. Its liver contained 51.7 ppm lead (wet weight). Based on these necropsy findings a diagnosis of lead poisoning was made.

  16. Childhood Lead Poisoning: Blueprint for Prevention.

    Science.gov (United States)

    Rochow, K. W. James; Rapuano, Maria

    Current programs to deal with childhood lead poisoning, the primary environmental disease of U.S. children, screen individual children, treat those with serious cases of lead poisoning, and subsequently return children to hazardous environments. This approach has led to repeated diagnoses of lead poisoning. This handbook is designed to convince…

  17. Revision Surgery of Deep Brain Stimulation Leads.

    Science.gov (United States)

    Falowski, Steven M; Bakay, Roy A E

    2016-07-01

    Deep brain stimulation (DBS) is widely used for various movement disorders. DBS lead revisions are becoming more common as the indications and number of cases increases. Patients undergoing DBS lead revisions at a single institution were retrospectively analyzed based on diagnosis, reason for revision, where the lead was relocated, and surgical technique. We reviewed 497 consecutive DBS lead placements and found that there was need for 25 DBS lead revisions with at least six months of follow-up. Loss of efficacy and development of adverse effects over time were the most common reasons for lead revision across all diagnosis. Lead malfunction was the least common. Ten patients requiring 19 DBS lead revisions that underwent their original surgery at another institution were also analyzed. Surgical technique dictated replacing with a new lead while maintaining brain position and tract with the old lead until final placement. Methods to seal exposed wire were developed. Surgical technique, as well as variable options are important in lead revision and can be dictated based on reason for revision. Over time patients who have had adequate relief with DBS placement may experience loss of efficacy and development of adverse effects requiring revision of the DBS lead to maintain its effects. © 2016 International Neuromodulation Society.

  18. Historical View on Lead: Guidelines and Regulations.

    Science.gov (United States)

    Pohl, Hana R; Ingber, Susan Z; Abadin, Henry G

    2017-04-10

    Lead has been used in many commodities for centuries. As a result, human exposure has occurred through the production and use of these lead-containing products. For example, leaded gasoline, lead-based paint, and lead solder/pipes in water distribution systems have been important in terms of exposure potential to the general population. Worker exposures occur in various industrial activities such as lead smelting and refining, battery manufacturing, steel welding or cutting operations, printing, and construction. Some industrial locations have also been a source of exposure to the surrounding communities. While the toxicity of relatively high lead exposures has been recognized for centuries, modern scientific studies have shown adverse health effects at very low doses, particularly in the developing nervous system of fetuses and children. This chapter reflects on historical and current views on lead toxicity. It also addresses the development and evolution of exposure prevention policies. As discussed here, these lead policies target a variety of potential exposure routes and sources. The changes reflect our better understanding of lead toxicity. The chapter provides lead-related guidelines and regulations currently valid in the U. S. and in many countries around the world. The reader will learn about the significant progress that has been made through regulations and guidelines to reduce exposure and prevent lead toxicity.

  19. LEAD POISONING IN ANCIENT ROME 1. INTRODUCTION

    African Journals Online (AJOL)

    of organic lead compounds such as tetra-ethyl lead, found in modern .... organic bone matrix. An adjustment formula taking the age of the adult into consideration is therefore necessary. There is no difference in bone lead content between men and women ... architect, Vitruvius (viii.6.10, 11), tells us that water from clay pipes.

  20. Load Dependent Lead Times and Sustainability

    DEFF Research Database (Denmark)

    Pahl, Julia; Voss, Stefan

    2016-01-01

    to prevent decreased quality or waste of production parts and products. This gains importance because waiting times imply longer lead times charging the production system with work in process inventories. Longer lead times can lead to quality losses due to depreciation, so that parts need to be reworked...

  1. Electrical polarization of lead bromide crystals. I

    NARCIS (Netherlands)

    Schoonman, A.; Macke, A.J.H.

    An attempt was made to measure electronic conductivity in lead bromide in equilibrium with lead, since experimental data on the cell −Pb/PbBr2/C+ in the literature are not consistent with existing theories. Combination of our results with published data for bromine-induced hole conduction in lead

  2. LEAD POISONING IN ANCIENT ROME 1. INTRODUCTION

    African Journals Online (AJOL)

    development of the region and the course of its history. 2. THE LEAD INDUSTRY IN ANCIENT ROME. 2.1 Lead production. From the 5th millennium BC ... production of olive oil were often made of or lined with lead (Cato,. De re rustica cv, lxvi). The wine fermentation process, too, often made use of casks or containers lined ...

  3. Distribution of Lead in Kerbside Soils

    African Journals Online (AJOL)

    NJD

    Lead in emissions from motor vehicles using leaded petrol are usually monitored by analysing gas samples. In view of the many problems associated with gas sampling, this project focussed on the analysis of lead in kerbside samples. To this end, soil .... was thoroughly mixed by shaking the soil in a clean plastic box.

  4. Early Reading Proficiency. Leading Indicator Spotlight

    Science.gov (United States)

    Musen, Lindsey

    2010-01-01

    In "Beyond Test Scores: Leading Indicators for Education," Foley and colleagues (2008) define leading indicators as those that "provide early signals of progress toward academic achievement" (p. 1) and stress that educators "need leading indicators to help them see the direction their efforts are going in and to take…

  5. A green lead hydrometallurgical process based on a hydrogen-lead oxide fuel cell.

    Science.gov (United States)

    Pan, Junqing; Sun, Yanzhi; Li, Wei; Knight, James; Manthiram, Arumugam

    2013-01-01

    The automobile industry consumed 9 million metric tons of lead in 2012 for lead-acid batteries. Recycling lead from spent lead-acid batteries is not only related to the sustainable development of the lead industry, but also to the reduction of lead pollution in the environment. The existing lead pyrometallurgical processes have two main issues, toxic lead emission into the environment and high energy consumption; the developing hydrometallurgical processes have the disadvantages of high electricity consumption, use of toxic chemicals and severe corrosion of metallic components. Here we demonstrate a new green hydrometallurgical process to recover lead based on a hydrogen-lead oxide fuel cell. High-purity lead, along with electricity, is produced with only water as the by-product. It has a >99.5% lead yield, which is higher than that of the existing pyrometallurgical processes (95-97%). This greatly reduces lead pollution to the environment.

  6. Eryptosis in lead-exposed workers

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar-Dorado, Itzel-Citlalli [Biochemistry Department, Centro de Investigación y Estudios Avanzados IPN, México, DF (Mexico); Hernández, Gerardo [Section of Methodology of Science, Centro de Investigación y Estudios Avanzados IPN, México, DF (Mexico); Quintanar-Escorza, Martha-Angelica [Faculty of Medicine, UJED, Durango, DGO (Mexico); Maldonado-Vega, María [CIATEC, León, GTO (Mexico); Rosas-Flores, Margarita [Biochemistry Department, Centro de Investigación y Estudios Avanzados IPN, México, DF (Mexico); Calderón-Salinas, José-Víctor, E-mail: jcalder@cinvestav.mx [Biochemistry Department, Centro de Investigación y Estudios Avanzados IPN, México, DF (Mexico)

    2014-12-01

    Eryptosis is a physiological phenomenon in which old and damaged erythrocytes are removed from circulation. Erythrocytes incubated with lead have exhibited major eryptosis. In the present work we found evidence of high levels of eryptosis in lead exposed workers possibly via oxidation. Blood samples were taken from 40 male workers exposed to lead (mean blood lead concentration 64.8 μg/dl) and non-exposed workers (4.2 μg/dl). The exposure to lead produced an intoxication characterized by 88.3% less δ-aminolevulinic acid dehydratase (δALAD) activity in lead exposed workers with respect to non-lead exposed workers. An increment of oxidation in lead exposed workers was characterized by 2.4 times higher thiobarbituric acid-reactive substance (TBARS) concentration and 32.8% lower reduced/oxidized glutathione (GSH/GSSG) ratio. Oxidative stress in erythrocytes of lead exposed workers is expressed in 192% higher free calcium concentration [Ca{sup 2+}]{sub i} and 1.6 times higher μ-calpain activity with respect to non-lead exposed workers. The adenosine triphosphate (ATP) concentration was not significantly different between the two worker groups. No externalization of phosphatidylserine (PS) was found in non-lead exposed workers (< 0.1%), but lead exposed workers showed 2.82% externalization. Lead intoxication induces eryptosis possibly through a molecular pathway that includes oxidation, depletion of reduced glutathione (GSH), increment of [Ca{sup 2+}], μ-calpain activation and externalization of PS in erythrocytes. Identifying molecular signals that induce eryptosis in lead intoxication is necessary to understand its physiopathology and chronic complications. - Graphical abstract: Fig. 1. (A) Blood lead concentration (PbB) and (B) phosphatidylserine externalization on erythrocyte membranes of non-lead exposed (□) and lead exposed workers (■). Values are mean ± SD. *Significantly different (P < 0.001). - Highlights: • Erythrocytes of lead exposed workers

  7. Eliminating Childhood Lead Poisoning: A Federal Strategy Targeting Lead Paint Hazards.

    Science.gov (United States)

    2000

    Noting that lead poisoning is a preventable disease, this report details a coordinated federal program to eliminate childhood lead poisoning in the United States. The report describes how lead poisoning harms children, how pervasive lead poisoning is, and how lead paint hazards in housing could be eliminated in 10 years. Following information on…

  8. Delayed visual maturation and lead pollution.

    Science.gov (United States)

    Gulson, B L; Yui, L A; Howarth, D

    1998-12-11

    Three children were born in the Broken Hill Australia lead mining community with delayed visual maturation of the optic nerve (blindness) within a period of 19 months. Because of the association with the lead pollution, the delayed visual maturation was attributed to lead exposure of the fetus during pregnancy. Lead isotopic analyses of the shed deciduous teeth from the three children demonstrate that they were not exposed to increased levels of lead from a mining or any other source during pregnancy and the etiology of the delayed visual maturation must be sought elsewhere.

  9. Occupational lead exposure and renin release.

    Science.gov (United States)

    Campbell, B C; Beattie, A D; Elliott, H L; Goldberg, A; Moore, M R; Beevers, D G; Tree, M

    1979-01-01

    Hypertension may result from chronic lead exposure. Lead poisoning arising from "moonshine whiskey" drinking has been associated with a rise in plasma renin activity. In the present study, plasma renin concentration following intravenous administration of frusemide was measured in eleven subjects with moderate or severe lead poisoning of industrial origin. The results were compared with those obtained for seven normal, control subjects. There was no significant difference in response obtained in the two groups. Industrial lead poisoning does not appear to affect renin release. The combined insult of lead and alcohol may explain the findings in the previous study.

  10. Percutaneous extraction of stented device leads.

    Science.gov (United States)

    Baranowski, Bryan; Wazni, Oussama; Chung, Roy; Martin, David O; Rickard, John; Tanaka-Esposito, Christine; Bassiouny, Mohammed; Wilkoff, Bruce L

    2012-05-01

    There are limited published data regarding the percutaneous extraction of device leads jailed by a venous stent. In this study we assessed the feasibility and safety of percutaneous extraction of stented device leads. We reviewed our experience percutaneously extracting 7 chronically implanted device leads jailed to the wall of the left innominate and/or subclavian veins by a previously placed stent. All leads were successfully extracted by using a percutaneous approach. Both pacing leads and defibrillator leads were extracted. The oldest pacing lead extracted was 14 years old. The oldest defibrillator lead extracted was 6 years old. Three of the leads were extracted with simple manual traction alone. The 4 remaining leads required a more complex, femoral extraction approach for successful removal. In our experience extracting 7 stented device leads, complete percutaneous removal was feasible 100% of the time using a combination of simple manual traction and a femoral approach. No major complications were associated with the extraction procedures. Copyright © 2012 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  11. Validation of defibrillator lead performance registry data

    DEFF Research Database (Denmark)

    Kristensen, Anders Elgaard; Larsen, Jacob Moesgaard; Nielsen, Jens Cosedis

    2017-01-01

    AIMS: The validity of registry data on defibrillator lead performance is described only sparsely, despite its clinical importance. This study investigated the validity of defibrillator lead performance registry data in a nationwide and population-based registry. METHODS AND RESULTS: We identified.......9% (95% CI: 85.2-90.2%) with a κ value of 0.82 (95% CI:0.78-0.86) representing an almost perfect match. CONCLUSION: The validity of data on defibrillator lead performance recorded in the DPIR is excellent for the specific types of lead intervention and good for the specific reasons for defibrillator lead...... intervention. The validity of the less detailed overall reasons for lead interventions commonly used to report lead performance is also excellent. These findings indicate high registry data quality appropriate for scientific analysis and industry-independent post-marketing surveillance....

  12. Lead sources in human diet in Greenland

    DEFF Research Database (Denmark)

    Bjerregaard, Peter; Johansen, Poul; Mulvad, Gert

    2004-01-01

    Although blood lead levels have declined in Greenland, they are still elevated despite the fact that lead levels in the Greenland environment are very low. Fragments of lead shot in game birds have been suggested as an important source of dietary exposure, and meals of sea birds, particularly eider......, contain high concentrations of lead. In a cross-sectional population survey in Greenland in 1993-1994, blood lead adjusted for age and sex was found to be associated with the reported consumption of sea birds. Participants reporting less than weekly intake of sea birds had blood lead concentrations...... of approximately 75 microg/L, whereas those who reported eating sea birds several times a week had concentrations of approximately 110 microg/L, and those who reported daily intake had concentrations of 170 microg/L (p = 0.01). Blood lead was not associated with dietary exposure to other local or imported food...

  13. Lead intoxication in Sydney Harbour Bridge workers.

    Science.gov (United States)

    Pollock, C A; Ibels, L S

    1988-02-01

    Thirty-eight Sydney Harbour Bridge workers were assessed for possible lead intoxication. Forty-seven per cent were found to have significant lead intoxication as assessed by calcium disodium edetate chelation (Ca EDTA) testing and were subsequently effectively and safely treated with Ca EDTA. The prevalence of neurological, constitutional, gastrointestinal and musculoskeletal symptoms was significantly greater in those with, than those without, lead toxicity. Although blood lead levels and, to a lesser extent, hematological parameters were of some use in diagnosis, they were not sufficiently sensitive and thus should not be used in screening workers at risk of lead intoxication. Ca EDTA testing remains the diagnostic method of choice. Patients exposed to lead dust and fumes, in whom symptoms of lead intoxication are present, should undergo such testing and if a positive result is obtained, then EDTA chelation therapy should be instituted.

  14. How lead loses its toxicity to plants

    Directory of Open Access Journals (Sweden)

    Małgorzata Wierzbicka

    2014-01-01

    Full Text Available This paper is a brief review of the problem of lead-in the environment, particularly constitutional tolerance to lead about which little is known. Taking Allium cepa L. roots as a model it has been shown that after an initial phase in which lead is toxic to cells, defence processes appear with the results that lead is no longer poisonous. The lead which penetrates into the root symplast is detoxified in vacuoles, cell walls and dictiosomal vesicles. Initial cells of the meristem (quescent centre which play a basic role in the root regeneration processes are protected against lead penetration. This surprising result is in agreement with the absence of any symptoms of lead poisoning in plants growing in natural conditions, and suggests that there is a defence mechanism specific only for plant cells.

  15. Experimental oral lead toxicity in young dogs

    Energy Technology Data Exchange (ETDEWEB)

    Stowe, H.D.; Goyer, R.A.; Krigman, M.M.; Wilson, M.; Cates, M.

    1973-02-01

    Litter-mate male pups were fed a calcium-and-phosphorus-low purified diet with and without 100 ppm of lead as lead acetate from age 6 to 18 weeks. Lead-toxic dogs exhibited cyclic but terminally severe anorexia and cachexia, significant anemia, normoblastocytosis and leukopenia within six weeks, hypoproteinemia, decreased serum albumin, ..cap alpha../sub 1/-globulin, ..beta../sub 2/-globulin, alkaline phosphatase and lactic dehydrogenase 1, elevated serum glutamic oxaloacetic and pyruvic transaminases, delayed closure of the thoracic vertebral epiphyses, lead lines in the distal radii and thoracic spinous processes, enlargement of liver, kidney, and brain, hepatic fatty metamorphosis, focal proximal renal tubular necrosis, hydropic degeneration of spermatognia, and lead inclusion body formation. Approximately 97% of the tissue lead was estimated to be skeletal; the greatest concentration of lead in the brain was found in the occipital gray matter.

  16. Editorial: Lead Risk Assessment and Health Effects.

    Science.gov (United States)

    Mielke, Howard W

    2016-06-14

    In 1980, Clair C. Patterson stated: "Sometime in the near future it probably will be shown that the older urban areas of the United States have been rendered more or less uninhabitable by the millions of tons of poisonous industrial lead residues that have accumulated in cities during the past century". We live in the near future about which this quote expressed concern. This special volume of 19 papers explores the status of scientific evidence regarding Dr. Patterson's statement on the habitability of the environments of communities. Authors from 10 countries describe a variety of lead issues in the context of large and small communities, smelter sites, lead industries, lead-based painted houses, and vehicle fuel treated with lead additives dispersed by traffic. These articles represent the microcosm of the larger health issues associated with lead. The challenges of lead risk require a concerted global action for primary prevention.

  17. Association of Lead Levels and Cerebral Palsy

    Directory of Open Access Journals (Sweden)

    Neha Bansal MD

    2017-03-01

    Full Text Available Background: Cerebral palsy is a common motor disability in childhood. Raised lead levels affect cognition. Children with cerebral palsy may have raised lead levels, further impairing their residual cognitive motor and behavioral abilities. Environmental exposure and abnormal eating habits may lead to increased lead levels. Aims and Objectives: To measure blood lead levels in children with cerebral palsy and compare them with healthy neurologically normal children. To correlate blood lead levels with environmental factors. Material and Methods: Design: Prospective case-control study. Setting: Tertiary care hospital. Participants: Cases comprised 34 children with cerebral palsy, and controls comprised 34 neurologically normal, age- and sex-matched children. Methods: Clinical and demographic details were recorded as per proforma. Detailed environmental history was recorded to know the source of exposure to lead. These children were investigated and treated as per protocol. Venous blood was collected in ethylenediaminetetraacetic acid vials for analysis of blood lead levels. Lead levels were estimated by Schimadzu Flame AA-6800 (atomic absorption spectrophotometer. Data were analyzed using SPSS version 17. P < .05 was taken as significant. Results: Mean blood lead levels were 9.20 ± 8.31 µg/dL in cerebral palsy cases and 2.89 ± 3.04 µg/dL in their controls (P < .001. Among children with cerebral palsy, 19 (55.88% children had blood lead levels ≥5 µg/dL. Lead levels in children with pica were 12.33 ± 10.02 µg/dL in comparison to children with no history of pica, 6.70 ± 4.60 µg/dL (P = .029. No correlation was found between hemoglobin and blood lead levels in cases and controls. Conclusion: In our study, blood lead levels are raised in children with cerebral palsy. However, further studies are required to show effects of raised levels in these children.

  18. Get the Lead Out: Facts about Childhood Lead Poisoning [and] Housekeeping Tips To Reduce Lead Exposure [and] Nutrition and Lead Poisoning [and] The Medical Consequences of Lead Poisoning [and] Lead Poisoning for Health Care Providers.

    Science.gov (United States)

    Illinois State Dept. of Public Health, Springfield.

    This document is comprised of five fact sheets from the Illinois Department of Public Health regarding childhood lead poisoning. Recent studies claim that childhood lead poisoning can contribute to problems later in life, such as academic failure, juvenile delinquency, and high blood pressure. Directed to parents, caregivers, and health care…

  19. Vagus nerve stimulation after lead revision.

    Science.gov (United States)

    Dlouhy, Brian J; Viljoen, Steven V; Kung, David K; Vogel, Timothy W; Granner, Mark A; Howard, Matthew A; Kawasaki, Hiroto

    2012-03-01

    Vagus nerve stimulation (VNS) has demonstrated benefit in patients with medically intractable partial epilepsy. As in other therapies with mechanical devices, hardware failure occurs, most notably within the VNS lead, requiring replacement. However, the spiral-designed lead electrodes wrapped around the vagus nerve are often encased in dense scar tissue hampering dissection and removal. The objective in this study was to characterize VNS lead failure and lead revision surgery and to examine VNS efficacy after placement of a new electrode on the previously used segment of vagus nerve. The authors reviewed all VNS lead revisions performed between October 2001 and August 2011 at the University of Iowa Hospitals and Clinics. Twenty-four patients underwent 25 lead revisions. In all cases, the helical electrodes were removed, and a new lead was placed on the previously used segment of vagus nerve. All inpatient and outpatient records of the 25 lead revisions were retrospectively reviewed. Four cases were second lead revisions, and 21 cases were first lead revisions. The average time to any revision was 5 years (range 1.8-11.1 years), with essentially no difference between a first and second lead revision. The most common reason for a revision was intrinsic lead failure resulting in high impedance (64%), and the most common symptom was increased seizure frequency (72%). The average duration of surgery for the initial implantation in the 15 patients whose VNS system was initially implanted at the authors' institution was much shorter (94 minutes) than the average duration of lead revision surgery (173 minutes). However, there was a significant trend toward shorter surgical times as more revision surgeries were performed. Sixteen of the 25 cases of lead revision were followed up for more than 3 months. In 15 of these 16 cases, the revision was as effective as the previous VNS lead. In most of these cases, both the severity and frequency of seizures were decreased to levels

  20. Exposure to lead from intake of coffee

    DEFF Research Database (Denmark)

    Hansen, Max; Sloth, Jens Jørgen; Rasmussen, Rie Romme

    Food and beverages is one of the primary sources of intake of and exposure to lead, with beverages accounting for almost 50%. Previous studies from Denmark have estimated that the intake of lead from coffee is very high and may contribute to up to 20% of the total lead intake from food and bevera......Food and beverages is one of the primary sources of intake of and exposure to lead, with beverages accounting for almost 50%. Previous studies from Denmark have estimated that the intake of lead from coffee is very high and may contribute to up to 20% of the total lead intake from food...... and beverages. This estimate is, however, based on older, non-published data. In the current project extensive chemical analyses of coffee beans, drinking water and ready-to-drink coffee have been performed. The results hereof have been compared to calculations of the total intake of lead from food...... and beverages. The results show that the intake of lead from coffee is considerably lower than previously estimated and account for 4.2% and 3.3% of the total lead intake from food and beverages for Danish men and women, respectively. It can generally be concluded that the intake of lead from coffee is low...

  1. Lead contamination of paint remediation workers' vehicles.

    Science.gov (United States)

    Boraiko, Carol; Wright, Eva M; Ralston, Faye

    2013-03-01

    Exposure to lead has been shown to be harmful to adults; it is a teratogen, it can damage the peripheral nervous system, and it adversely affects the reproductive system. Professional lead-based paint remediation workers are at risk of exposure to lead dust. The authors' study was conducted to determine if these remediation workers transfer lead from their work site to their vehicles and then potentially expose their families. It was hypothesized that remediation workers transported the lead from the remediation work site to the floorboards of their vehicles due to not following required protective equipment use. The laboratory's level of quantitation for lead on the wipe samples, 10 microg/ft2, was used to indicate lead contamination. This level was exceeded in 50% of the floorboards sampled. These results confirm that many vehicle floorboards used by remediation workers are contaminated with lead dust, potentially resulting in transfer of lead dust. The ultimate detrimental outcome could be the transfer of lead particles to other family members, causing the poisoning of a child or other at-risk person.

  2. Hypogonadism in chronically lead-poisoned men.

    Science.gov (United States)

    Braunstein, G D; Dahlgren, J; Loriaux, D L

    1978-01-01

    The hypothalamic-pituitary-testicular axis was evaluated in 10 men with occupational lead exposure, 9 of whom had noted a decrease in libido and frequency of intercourse following this exposure. 6 of these men had clinically apparent lead poisoning while 4 were classified as being only lead-exposed. Results of the endocrine evaluation of these patients were compared to those obtained on 9 age and socioeconomically matched control patients. Both lead poisoned and lead-exposed patients had reduced basal serum testosterone levels and normal basal serum testosterone-estradiol-binding globulin capacity, estradiol, LH, FSH, and prolactin levels. Both groups demonstrated an appropriate rise in serum testosterone following hCG stimulation and a normal increment in serum FSH in response to clomiphene citrate and gonadotropin-releasing hormone in comparison to the control group. The lead poisoned patients demonstrated a significantly reduced increment in serum LH after clomiphene citrate and gonadotropin-releasing hormone administration while the lead-exposed patients had normal LH dynamics. Testicular biopsies carried out on the 2 most severely lead-poisoned men showed peritubular fibrosis, oligospermia, and vacuolization of the Sertoli cells. These results suggest that lead poisoning may lead to a pituitary-hypothalamic defect in LH secretion and may also result in direct testicular seminiferous tubular injury.

  3. Lead in food and food containers

    Energy Technology Data Exchange (ETDEWEB)

    Chu, A.O. [Univ. of California, Berkeley, CA (United States)

    1994-04-01

    We investigated food and food containers suspected of containing high levels of lead. Food containers investigated were bought in Northern California and were linked to several cases of lead poisoning in children and adults. Coffee mugs and Mexican pottery were leached with acetic and citric acid, respectively. The amount of lead leached from the lip and rim area of eleven coffee mugs ranged from non detectable to 79 ppm. Lead leached from Mexican potteries ranged from non detectable to 584 ppm of lead. Although there are no regulations pertaining to the amount of lead in the lip and rim area of ceramic ware, under California proposition 65 vendors are required to warn consumers of the presence of toxic materials in consumer products. Foods analyzed for lead content were candy and beans. A sample of tamarindo candy taken from the center of its storage container, a mexican clay pot, was found to contain 1.0 ppm of lead, while the candy in contact with the glaze contained 16 ppm of lead. Beans cooked in Mexican clay cooking pots contained lead ranging from 2.8 to 9.2 ppm. Two-thirds of the food containers investigated and the food analyzed did not meet the provisional Total Tolerable Daily Intake level let by the U.S. FDA, assuming a reasonable amount of liquid and food was ingested.

  4. Association of Lead Levels and Cerebral Palsy.

    Science.gov (United States)

    Bansal, Neha; Aggarwal, Anju; Faridi, M M A; Sharma, Tusha; Baneerjee, B D

    2017-01-01

    Background: Cerebral palsy is a common motor disability in childhood. Raised lead levels affect cognition. Children with cerebral palsy may have raised lead levels, further impairing their residual cognitive motor and behavioral abilities. Environmental exposure and abnormal eating habits may lead to increased lead levels. Aims and Objectives: To measure blood lead levels in children with cerebral palsy and compare them with healthy neurologically normal children. To correlate blood lead levels with environmental factors. Material and Methods:Design: Prospective case-control study. Setting: Tertiary care hospital. Participants: Cases comprised 34 children with cerebral palsy, and controls comprised 34 neurologically normal, age- and sex-matched children. Methods: Clinical and demographic details were recorded as per proforma. Detailed environmental history was recorded to know the source of exposure to lead. These children were investigated and treated as per protocol. Venous blood was collected in ethylenediaminetetraacetic acid vials for analysis of blood lead levels. Lead levels were estimated by Schimadzu Flame AA-6800 (atomic absorption spectrophotometer). Data were analyzed using SPSS version 17. P cerebral palsy cases and 2.89 ± 3.04 µg/dL in their controls (P cerebral palsy, 19 (55.88%) children had blood lead levels ≥5 µg/dL. Lead levels in children with pica were 12.33 ± 10.02 µg/dL in comparison to children with no history of pica, 6.70 ± 4.60 µg/dL (P = .029). No correlation was found between hemoglobin and blood lead levels in cases and controls. Conclusion: In our study, blood lead levels are raised in children with cerebral palsy. However, further studies are required to show effects of raised levels in these children.

  5. Assessment of lead in cosmetic products.

    Science.gov (United States)

    Al-Saleh, Iman; Al-Enazi, Sami; Shinwari, Neptune

    2009-07-01

    There have been a number of recent reports in the media and on the internet about the presence of lead in brand-names lipsticks. This has drawn our attention to assess the safety of various cheap brands of cosmetics sold at 2-riyals stores in Saudi market that are imported from countries where safety regulations are poorly enforced as well as they lack perfect conditions for manufacturing. Lead contents were determined in 26 and eight different brands of lipsticks and eye shadows using the Zeeman atomic absorption spectrophotometer coupled to graphite tube atomizer after an acid digestion procedure. Lead was detected in all the studied samples. The median (25th-75th percentile) lead content in 72 lipsticks samples was 0.73 (0.49-1.793) PPM wet wt. in the range of 0.27-3760 PPM wet wt. There were four brands of lipsticks with lead content above the FDA lead limit as impurities in color additives (20 PPM). The FDA does not set a limit for lead in lipstick. Three of them were extremely high points and considered outliers. The median (25th-75th percentile) lead contents in pressed powder eye shadow was 1.38 (0.944-1.854) PPM wet wt. (n=22) in the range of 0.42-58.7 PPM wet wt. One brand was above 20 PPM the US FDA's lead limit as impurities. The overall results indicate that lead in lipsticks and eye shadows are below the FDA lead limit as impurities and, thus, probably have no significant toxicological effects. Nevertheless, few brands had lead content above 20 PPM that might put consumers at the risk of lead poisoning. Lead is a cumulative, and applying lead-containing cosmetics several times a day or every day, can potentially add up to significant exposure levels. Pregnant and nursing mothers are vulnerable population because lead passes through placenta and human milk and affect fetus or infant's developments. Our findings call for an immediate mandatory regular testing program to check lead and other toxic metals in lipsticks and other cosmetic products imported

  6. The refining of secondary lead for use in advanced lead-acid batteries

    Science.gov (United States)

    Ellis, Timothy W.; Mirza, Abbas H.

    Secondary lead, i.e. material produced by the recycling of lead-acid batteries has become the primary source of lead in much of the world. This has been important to the secondary lead industry as other uses have dwindled, e.g. lead based pigments, chemicals, fuel additives, solders and CRT glasses [1]. Presently, battery manufacturing accounts for greater than 80% of lead consumption while recycled lead accounts for approximately the same market share of lead supply. These two facts strongly demonstrate the battery manufacturing and recycled lead are intimately coupled in everyday life. In this paper we will explore how recycled lead has become the material of choice for battery construction through the development of a recovery and refining process that exceeds the industries requirements. Particular focus will be on addressing the results presented by Prengaman [2] on the effects of contaminant or tramp elements on gassing in lead-acid batteries.

  7. Lead Poisoning Due to Herbal Medications.

    Science.gov (United States)

    Chambial, Shailja; Bhardwaj, Pankaj; Mahdi, Abbas Ali; Sharma, Praveen

    2017-06-01

    Lead ranks as one of the most serious environmental poisons all over the world amongst toxic heavy metals with no known biological function useful for the human body. A case of lead toxicity due to consumption of herbal medicine is being discussed. The case presented with gastrointestinal complaints and history of intake of herbal medicines for diabetes control for past 8 months. The analysis of the powdered herbal medicine procured from ayurveda practitioner was found to have high content of lead responsible for the lead toxicity. The patient is under regular followup. He has improved symptomatically on chelating therapy and blood lead levels have gradually improved. Regular awareness programs should be conducted in the population regarding possible exposure through home made herbal remedies so that general public can be made aware of the dangerous side effects of lead and other heavy metals on health.

  8. Innovation Management, Lead Users and Social Media

    DEFF Research Database (Denmark)

    Ernst, M.; Brem, Alexander; Voigt, K.-I.

    2013-01-01

    to integrate external knowledge into innovation processes. This approach is discussed by considering the integration of customers and especially Lead-Users into corporate product development. Based on the concept of Open Innovation, we reflect the role of Lead-Users in the innovation process critically....... Mounting on our reflections, we show the potentials of social media for integrating Lead-Users and develop a conceptual framework for the integration of Lead-Users using different social media applications. Findings — In this paper, a conceptual framework for integrating Lead-Users by using different...... social media applications is developed and introduced. Originality/value — The unique conceptual framework derived in this chapter is enriched with a discussion of the challenges resulting from the implementation of Lead-User integration along with social media in corporate innovation management...

  9. Apparatus and methods for purifying lead

    Science.gov (United States)

    Tunison, Harmon M.

    2016-01-12

    Disclosed is an exemplary method of purifying lead which includes the steps of placing lead and a fluoride salt blend in a container; forming a first fluid of molten lead at a first temperature; forming a second fluid of the molten fluoride salt blend at a second temperature higher than the first temperature; mixing the first fluid and the second fluid together; separating the two fluids; solidifying the molten fluoride salt blend at a temperature above a melting point of the lead; and removing the molten lead from the container. In certain exemplary methods the molten lead is removed from the container by decanting. In still other exemplary methods the molten salt blend is a Lewis base fluoride eutectic salt blend, and in yet other exemplary methods the molten salt blend contains sodium fluoride, lithium fluoride, and potassium fluoride.

  10. Extraction of superfluous device leads: A comparison with removal of infected leads.

    Science.gov (United States)

    Huang, Xin-Miao; Fu, Haixia; Osborn, Michael J; Asirvatham, Samuel J; McLeod, Christopher J; Glickson, Michael; Acker, Nancy G; Friedman, Paul A; Cha, Yong-Mei

    2015-06-01

    Although increasingly more lead extraction was performed for superfluous leads, the extraction of such leads remains controversial. The objective of this study was to determine the outcomes and complications of transvenous extraction of superfluous leads in a single center in the era of laser technology. Four hundred eighty transvenous lead extraction procedures performed from January 2001 through October 2012 at Mayo Clinic (Rochester, Minnesota) were retrospectively reviewed. Of these, 123 procedures were performed for superfluous functional or nonfunctional leads. Data were collected from electronic medical records and an institutional database of cardiovascular implantable electronic devices. A total of 167 superfluous leads (mean [SD] lead duration 53 [53] months; median 34 months) were removed during the 123 procedures. Forty-one percent of procedures were for lead malfunction. The procedural complete-success rate was 96.7%. Major complications occurred in 1 patient (0.8%), who had a superior vena cava tear that required thoracotomy. Superfluous leads had been implanted for a shorter period of time than infected leads (mean [SD] 53 [53] vs 81 [59] months; P leads than for leads associated with infection (97% vs 92%; P = .05). Transvenous extraction of superfluous leads is highly successful, with few procedural complications. Extraction of superfluous leads at the time of device upgrade or lead revision is considered reasonable to avoid the increasing risk of extraction complications with lead aging. Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  11. Lead in tissues of mallard ducks dosed with two types of lead shot

    Science.gov (United States)

    Finley, M.T.; Dieter, M.P.; Locke, L.N.

    1976-01-01

    Mallard ducks (Anas platyrhynchos) were sacrificed one month after ingesting one number 4 all-lead shot or one number 4 lead-iron shot. Livers, kidneys, blood, wingbones, and eggs were analyzed for lead by atomic absorption. Necropsy of sacrificed ducks failed to reveal any of the tissue lesions usually associated with lead poisoning in waterfowl. Lead levels in ducks given all-lead shot averaged about twice those in ducks given lead-iron shot, reflecting the amount of lead in the two types of shot. Lead in the blood of ducks dosed with all-lead shot averaged 0.64 ppm, and 0.28 ppm in ducks given lead-iron shot. Lead residues in livers and kidneys of females given all-lead shot were significantly higher than in males. In both dosed groups, lead levels in wingbones of females were about 10 times those in males, and were significantly correlated with the number of eggs laid after dosage. Lead levels in contents and shells of eggs laid by hens dosed with all-lead shot were about twice those in eggs laid by hens dosed with lead-iron shot. Eggshells were found to best reflect levels of lead in the blood. Our results indicate that mallards maintained on a balanced diet and dosed with one lead shot may not accumulate extremely high lead levels in the liver and kidney. However, extremely high lead deposition may result in the bone of laying hens after ingesting sublethal amounts of lead shot as a result of mobilization of calcium from the bone during eggshell formation.

  12. NASA DOD Lead Free Electronics Project

    Science.gov (United States)

    Kessel, Kurt R.

    2008-01-01

    The primary'technical objective of this project is to undertake comprehensive testing to generate information on failure modes/criteria to better understand the reliability of: Packages (e.g., Thin Small Outline Package [TSOP], Ball Grid Array [BGA], Plastic Dual In-line Package [PDIPD assembled and reworked with lead-free alloys Packages (e.g., TSOP, BGA, PDIP) assembled and reworked with mixed (lead/lead-free) alloys.

  13. Lead in ancient Rome's city waters

    OpenAIRE

    Delile, Hugo; Blichert-Toft, Janne; Goiran, Jean-Philippe; Keay, Simon; Albarède, Francis

    2014-01-01

    International audience; It is now universally accepted that utilization of lead for domestic purposes and water distribution presents a major health hazard. The ancient Roman world was unaware of these risks. How far the gigantic network of lead pipes used in ancient Rome compromised public health in the city is unknown. Lead isotopes in sediments from the harbor of Imperial Rome register the presence of a strong anthropogenic component during the beginning of the Common Era and the Early Mid...

  14. PRODUCTION OF LEAD-FREE SOLDER POWDERS

    OpenAIRE

    Mustafacan , Kutsal

    2014-01-01

    The intentional use of conventional tin-lead (Sn-Pb) solder alloys was restricted with legislations across the world due to the toxic nature and the adverse effects of lead on health and the environment. Consequently, the development of new lead-free solder alloys has become a significant area of research. In addition to these health concerns, the continuing miniaturization trend of the consumer electronics has been pushing the production of solders from bulk form to powder form. In this stud...

  15. Healthy People 2020: Leading Health Indicators

    Science.gov (United States)

    ... Maternal, Infant, and Child Health Mental Health Nutrition, Physical Activity, and Obesity Oral Health Reproductive and Sexual Health Social Determinants Substance Abuse Tobacco Leading Health Indicators Healthy ...

  16. Toxicity of dietary lead in young cockerels.

    Science.gov (United States)

    Franson, J C; Custer, T W

    1982-12-01

    Day-old cockerels received 1850 ppm dietary lead for 4 wks. Blood delta-aminolevulinic acid dehydratase (ALAD) activity was reduced to 1.6% of control activity by the end of the study. Hemoglobin concentration (Hb) in lead-exposed cockerels was significantly less than that of controls at 7, 14, and 28 days, and packed cell volume (PCV) was significantly reduced at 14 days. Blood lead residues reached 832 micrograms/dl in exposed cockerels; kidney residues were about three times liver residues. At the termination of the study mean body weight of lead-exposed birds was 47% of controls.

  17. Testing of sealed lead-acid batteries

    Energy Technology Data Exchange (ETDEWEB)

    Bush, D.M.; Sealey, J.D.; Miller, D.W.

    1984-02-01

    In early January 1981, Sandia National Laboratories began testing sealed lead-acid batteries which were being developed under Sandia contracts. The goal was to develop a totally maintenance-free sealed lead-acid battery capable of deep-discharge operation in a photovoltaic power system. Sealed lead-acid batteries and a group of conventional, flooded lead-acid batteries were exposed to a matrix test plan, with some approaching 1000 cycles. This performance was achieved with the standard National Electrical Manufacturers' Association cycle test, as well as the partial-state-of-charge cycle test. Modes of failure are being investigated.

  18. Lead in wild blackberries from suburban roadsides

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, J.G.

    1979-01-01

    A mean lead content of 0.79 mg kg/sup -1/ was found for wild blackberries from roadside hedgerows in a suburban area of Glasgow. This represents a five-fold enhancement in lead content relative to blackberries from non-roadside environments and can be attributed to the emission of lead-containing compounds from car exhaust. Washing typically removed less than or equal to 0.1 mg kg/sup -1/. However, M.A.F.F. (1975) recommended limits for lead in fresh food (1 mg kg/sup -1/) and canned fruits and preserves (2 mg kg/sup -1/) were not, in general, exceeded.

  19. Production Planning with Load Dependent Lead Times

    DEFF Research Database (Denmark)

    Pahl, Julia

    2005-01-01

    Lead times impact the performance of the supply chain significantly. Although there is a large literature concerning queuing models for the analysis of the relationship between capacity utilization and lead times, and there is a substantial literature concerning control and order release policies...... that take lead times into consideration, there have been only few papers describing models at the aggregate planning level that recognize the relationship between the planned utilization of capacity and lead times. In this paper we provide an in-depth discussion of the state-of-the art in this literature...

  20. Lead poisoning in woodpeckers in Sweden.

    Science.gov (United States)

    Mörner, T; Petersson, L

    1999-10-01

    Lead poisoning was demonstrated in two gray-headed woodpeckers (Picus canus) and one white-backed woodpecker (Dendrocopus leucotos) in Sweden; they had liver lead levels between 9.4 and 26.2 mg(-1) wet weight. At necropsy one gray-headed woodpecker showed signs of emaciation and the other one had severe traumatic injuries, caused by a cat. The white-backed woodpecker died in the transportation box during a translocation program. The source of the lead could not be determined, but it was suspected that it may have originated from lead pellets shot into trees and picked out by the woodpeckers during food search.

  1. Can deunionization lead to international outsourcing?

    National Research Council Canada - National Science Library

    Lommerud, Kjell Erik; Meland, Frode; Straume, Odd Rune

    2009-01-01

    .... Such outsourcing leads to increased wages for the remaining in-house production. We find that stronger unions, which imply higher domestic wages, reduce incentives for international outsourcing...

  2. Learning Media Programme, leads for innovation

    NARCIS (Netherlands)

    Westera, Wim

    2010-01-01

    Westera, W. (2010, 25 January). Learning Media Programme, leads for innovation. Presentation for Deans of Open University of the Netherlands, Heerlen, The Netherlands: Open University of the Netherlands.

  3. 76 FR 12944 - Children's Products Containing Lead; Technological Feasibility of 100 ppm for Lead Content...

    Science.gov (United States)

    2011-03-09

    ... COMMISSION Children's Products Containing Lead; Technological Feasibility of 100 ppm for Lead Content; Notice... feasibility of meeting the 100 ppm lead content limit for children's products and associated public health... laboratories regarding the technological feasibility of meeting the 100 ppm lead content limit. At the hearing...

  4. 76 FR 44463 - Children's Products Containing Lead; Technological Feasibility of 100 ppm for Lead Content...

    Science.gov (United States)

    2011-07-26

    ... Lead Content; Notice of Effective Date of 100 ppm Lead Content Limit in Children's Products AGENCY: U.S... technological feasibility of meeting the 100 ppm lead content limit for children's products and associated... statutory 100 ppm lead content limit on August 14, 2011, unless otherwise excluded under CPSC regulations.\\1...

  5. The relationship between environmental lead and blood lead in children : a study in environmental epidemiology

    NARCIS (Netherlands)

    Brunekreef, B.

    1985-01-01

    This study deals with the relationship between environmental lead and blood lead in children.
    Chapter 1 provides a summary of the environmental health aspects of lead. The occurrence of lead in the environment and in man is described; children are discussed as a population at

  6. Evaluation of the use of salivary lead levels as a surrogate of blood lead or plasma lead levels in lead exposed subjects

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Fernando [Universidade de Sao Paulo, Departamento de Analises Clinicas, Toxicologicas e Bromatologicas, Faculdade de Ciencias Farmaceuticas de Ribeirao Preto, Ribeirao Preto, SP (Brazil); Correa Rodrigues, Maria H.; Buzalaf, Maria R. [Universidade de Sao Paulo, Departamento de Ciencias Biologicas/Bioquimica, Faculdade de Odontologia de Bauru, Bauru, SP (Brazil); Krug, Francisco J. [Universidade de Sao Paulo, Centro de Energia Nuclear na Agricultura, Piracicaba, SP (Brazil); Gerlach, Raquel F. [Universidade de Sao Paulo, Departamento de Morfologia, Estomatologia e Fisiologia, Faculdade de Odontologia de Ribeirao Preto, Ribeirao Preto, SP (Brazil); Tanus-Santos, Jose E. [Universidade de Sao Paulo, Departamento de Farmacologia, Faculdade de Medicina de Ribeirao Preto, Ribeirao Preto, SP (Brazil)

    2006-10-15

    We conducted a study to evaluate the use of parotid salivary lead (Pb-saliva) levels as a surrogate of the blood lead (Pb-B) or plasma lead levels (Pb-P) to diagnose lead exposure. The relationship between these biomarkers was assessed in a lead exposed population. Pb-saliva and Pb-P were determined by inductively coupled plasma mass spectrometry, while in whole blood lead was determined by graphite furnace atomic absorption spectrometry. We studied 88 adults (31 men and 57 women) from 18 to 60 years old. Pb-saliva levels varied from 0.05 to 4.4 {mu}g/l, with a mean of 0.85 {mu}g/l. Blood lead levels varied from 32.0 to 428.0 {mu}g/l in men (mean 112.3 {mu}g/l) and from 25.0 to 263.0 {mu}g/l (mean 63.5 {mu}g/l) in women. Corresponding Pb-Ps were 0.02-2.50 {mu}g/l (mean 0.77 {mu}g/l) and 0.03-1.6 {mu}g/l (mean 0.42 {mu}g/l) in men and women, respectively. A weak correlation was found between Log Pb-saliva and Log Pb-B (r=0.277, P<0.008), and between Log Pb-saliva and Log Pb-P (r=0.280, P=0.006). The Pb-saliva/Pb-P ratio ranged from 0.20 to 18.0. Age or gender does not affect Pb-saliva levels or Pb-saliva/Pb-P ratio. Taken together, these results suggest that salivary lead may not be used as a biomarker to diagnose lead exposure nor as a surrogate of plasma lead levels at least for low to moderately lead exposed population. (orig.)

  7. Measurement Challenges at Low Blood Lead Levels.

    Science.gov (United States)

    Caldwell, Kathleen L; Cheng, Po-Yung; Jarrett, Jeffery M; Makhmudov, Amir; Vance, Kathryn; Ward, Cynthia D; Jones, Robert L; Mortensen, Mary E

    2017-08-01

    In 2012, the Centers for Disease Control and Prevention (CDC) adopted its Advisory Committee on Childhood Lead Poisoning Prevention recommendation to use a population-based reference value to identify children and environments associated with lead hazards. The current reference value of 5 μg/dL is calculated as the 97.5th percentile of the distribution of blood lead levels (BLLs) in children 1 to 5 years old from 2007 to 2010 NHANES data. We calculated and updated selected percentiles, including the 97.5th percentile, by using NHANES 2011 to 2014 blood lead data and examined demographic characteristics of children whose blood lead was ≥90th percentile value. The 97.5th percentile BLL of 3.48 µg/dL highlighted analytical laboratory and clinical interpretation challenges of blood lead measurements ≤5 μg/dL. Review of 5 years of results for target blood lead values Lead and Multi-Element Proficiency quality assurance program showed 40% unable to quantify and reported a nondetectable result at a target blood lead value of 1.48 µg/dL, compared with 5.5% at a target BLL of 4.60 µg/dL. We describe actions taken at the CDC's Environmental Health Laboratory in the National Center for Environmental Health, which measures blood lead for NHANES, to improve analytical accuracy and precision and to reduce external lead contamination during blood collection and analysis. Copyright © 2017 by the American Academy of Pediatrics.

  8. Lead: Aspects of its ecology and environmental toxicity. [physiological effects of lead compound contamination of environment

    Science.gov (United States)

    Siegel, S. M.

    1973-01-01

    An analysis of lead toxicity in the Hawaiian environment was conducted. It was determined that lead enters the environment as an industrial contaminant resulting from the combustion of leaded gasoline. The amount of lead absorbed by the plants in various parts of the Hawaiian Islands is reported. The disposition of lead in the sediments of canals and yacht basins was investigated. The methods for conducting the surveys of lead content are described. Possible consequences of continued environmental pollution by burning leaded gasoline are discussed.

  9. Effect of Breast Milk Lead on Infant Blood Lead Levels at 1 Month of Age

    OpenAIRE

    Téllez-Rojo, Martha María; Hu, Howard; Hernández-Avila, Mauricio; Ettinger, Adrienne S.; Amarasiriwardena, Chitra J.; Bellinger, David C.; Peterson, Karen E.; Schwartz, Joel David

    2004-01-01

    Nursing infants may be exposed to lead from breast milk, but relatively few data exist with which to evaluate and quantify this relationship. This route of exposure constitutes a potential infant hazard from mothers with current ongoing exposure to lead as well as from mothers who have been exposed previously due to the redistribution of cumulative maternal bone lead stores. We studied the relationship between maternal breast milk lead and infant blood lead levels among 255 mother?infant pair...

  10. The energy efficiency of lead selfsputtering

    DEFF Research Database (Denmark)

    Andersen, Hans Henrik

    1968-01-01

    The sputtering efficiency (i.e. ratio between sputtered energy and impinging ion energy) has been measured for 30–75‐keV lead ions impinging on polycrystalline lead. The results are in good agreement with recent theoretical estimates. © 1968 The American Institute of Physics...

  11. Leading Learning: Science Departments and the Chair

    Science.gov (United States)

    Melville, Wayne; Campbell, Todd; Jones, Doug

    2016-01-01

    In this article, we have considered the role of the chair in leading the learning necessary for a department to become effective in the teaching and learning of science from a reformed perspective. We conceptualize the phrase "leading learning" to mean the chair's constitution of influence, power, and authority to intentionally impact…

  12. STABILIZATION OF LEAD-BASED PAINT WASTE

    Science.gov (United States)

    This study evaluated the ability of a cementitious stabilizing agent to reduce leachable lead from lead-based paint waste removed from substrate via blasting, and to evaluate the mechanism by which the reduction occurs. Testing demonstrated that the representative cementitious ag...

  13. Snapshots from a leading eco-city

    DEFF Research Database (Denmark)

    Mehlsen, Camilla

    2009-01-01

    The government of Singapore wants to make Singapore the leading Eco-city in Asia. Professor Kim Chuan Goh explains why this might be an achievable goal.......The government of Singapore wants to make Singapore the leading Eco-city in Asia. Professor Kim Chuan Goh explains why this might be an achievable goal....

  14. SHORT COMMUNICATION REMOVAL OF LEAD IONS FROM ...

    African Journals Online (AJOL)

    a

    ABSTRACT. A simple cost effective and eco-friendly method for the remediation of lead from industrial wastewater has been investigated. A novel biomaterial, Tridax procumbens (Asteraceae) a medicinal plant, was used for the removal of lead ions from synthetic wastewater and the method was also applied for real sample ...

  15. 29 CFR 1926.62 - Lead.

    Science.gov (United States)

    2010-07-01

    ... of paragraph (d)(10) of this section. (5) Negative initial determination. Where a determination... used to determine methods selected for controlling exposure to lead; (C) A report of the technology... potentially harmful effects of exposure to lead. (vii) The employer shall assure that the containers of...

  16. DROP AMALGAM VOLTAMMETRIC STUDY OF LEAD ...

    African Journals Online (AJOL)

    a

    ABSTRACT. A study of inorganic complexation of lead using drop amalgam voltammetry is described. The study has been carried out in simulated salt lake water and at ionic strength of. 7.35 M, the predetermined ionic strength of Lake Katwe. The complexation of lead with the simple ligands (Cl-, CO3. 2-) created anodic ...

  17. Leading edge gypsy moth population dynamics

    Science.gov (United States)

    M. R. Carter; F. W. Ravlin; M. L. McManus

    1991-01-01

    Leading edge gypsy moth populations have been the focus of several intervention programs (MDIPM, AIPM). Knowledge of gypsy moth population dynamics in leading edge area is crucial for effective management. Populations in these areas tend to reach outbreak levels (noticeable defoliation) within three to four years after egg masses are first detected. Pheromone traps...

  18. 29 CFR 1915.1025 - Lead.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Lead. 1915.1025 Section 1915.1025 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED... Lead. Note: The requirements applicable to shipyard employment under this section are identical to...

  19. Implantable Cardiac Defibrillator Lead Failure and Management.

    Science.gov (United States)

    Swerdlow, Charles D; Kalahasty, Gautham; Ellenbogen, Kenneth A

    2016-03-22

    The implantable-cardioverter defibrillator (ICD) lead is the most vulnerable component of the ICD system. Despite advanced engineering design, sophisticated manufacturing techniques, and extensive bench, pre-clinical, and clinical testing, lead failure (LF) remains the Achilles' heel of the ICD system. ICD LF has a broad range of adverse outcomes, ranging from intermittent inappropriate pacing to proarrhythmia leading to patient mortality. ICD LF is often considered in the context of design or construction defects, but is more appropriately considered in the context of the finite service life of a mechanical component placed in chemically stressful environment and subjected to continuous mechanical stresses. This clinical review summarizes LF mechanisms, assessment, and differential diagnosis of LF, including lead diagnostics, recent prominent lead recalls, and management of LF and functioning, but recalled leads. Despite recent advances in lead technology, physicians will likely continue to need to understand how to manage patients with transvenous ICD leads. Copyright © 2016 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  20. [Children exposure to lead in contaminated sites].

    Science.gov (United States)

    Flores-Ramírez, Rogelio; Rico-Escobar, Edna; Núñez-Monreal, Jorge E; García-Nieto, Edelmira; Carrizales, Leticia; Ilizaliturri-Hernández, César; Díaz-Barriga, Fernando

    2012-01-01

    To assess the exposure to lead in children living in various types of contaminated sites. The study was conducted from June 2008 to December 2009 at four sites in Mexico: Avalos metallurgical, Chihuahua; Morales metallurgical, San Luis Potosí (SLP); Trinidad pottery area, Tlaxcala and Cedral mine site, SLP. These sites contain different sources of lead. The metal levels were quantified in outdoor dust and in peripheral blood of children. Lead dust concentrations exceed the National Guidelines for residential soils (400 mg/kg) in a range of values for the four sites from 62 to 5 187 mg/kg. Regarding biological monitoring, the studied children showed maximum lead blood levels of 22 µg/dL in Cedral, 31 µg/dL in Morales, 32 µg/dL in Avalos, and 52 µg/dL in Trinidad. It is important to mention that in all the studied sites, a significative positive correlation was found between blood lead levels and the lead concentrations in dust. These sites are an example of the health risks related to lead exposure in Mexico; therefore, there is an urgent need for a national public health program aimed at reducing lead exposure in vulnerable populations.

  1. SPECTROSCOPIC STUDIES AND THERMAL ANALYSIS OF LEAD ...

    African Journals Online (AJOL)

    a

    KEY WORDS: Lead, Tin, Schiff base, Infrared spectra, Thermal analysis. INTRODUCTION ... elemental analysis, infrared spectra as well as by their thermal analysis (DTA and TG). Analysis results are reported in Table 1. The percentage of lead and tin metals were determined using ..... PbO + 5C + 10C2H2 + N2 + CO.

  2. SQUARE WAVE VOLTAMMETRIC DETERMINATION OF LEAD IN ...

    African Journals Online (AJOL)

    2011-12-31

    Dec 31, 2011 ... ABSTRACT. A simple sensitive square wave voltammetric method for the determination of lead contamination of several kohl samples purchased from Algeria retail stores was developed using glassy carbon electrode. The peak current response of 5 standards aqueous solution of lead in NaNO3 as ...

  3. Indigenous tooth powders = covert lead poisoning?

    Science.gov (United States)

    Hegde, Sapna; Shubha, A B; Rao, B Dinesh

    2013-01-01

    The present study aimed to measure the concentration of lead in various indigenous preparations of tooth powders available and used locally in and around Udaipur, Rajasthan, India. Seven different brands of tooth powders manufactured and/or marketed locally were obtained from stores all over Udaipur city. Some home-made powders commonly used for cleaning teeth were also collected. The tooth powders were analyzed for lead content by atomic absorption spectrophotometry. All tooth powders tested were found to contain high levels of lead ranging from 21 ppm to 82 ppm, above the maximum permissible level of 20 ppm prescribed by the Bureau of Indian Standards. Indigenous tooth powders contain high levels of lead and thus may be a source of lead poisoning that is often overlooked.

  4. Exploring how lead users develop radical innovation

    DEFF Research Database (Denmark)

    Lettl, Christopher; Gemuenden, Hans Georg; Hienerth, C.

    2008-01-01

    In this study, we explore how lead users develop radical innovations outside of manufacturing firms. We analyze the transition from a very early stage of activities to the ultimate commercialization of these innovations. The focus in this context is on the initiatives undertaken by lead users...... in order to transform their radically new solutions into functional prototypes and then to convince established manufacturers of the technological and market potential of their innovations. Using a comparative case study design in the high-tech field of medical equipment technology, we find that individual...... lead users as surgeons launch entrepreneurial activities and bridge periods in which established medical equipment manufacturers would not risk investing in radical innovations. By doing so, lead users create the conditions usually provided in manufacturer-initiated lead user projects, including...

  5. Vector boson and Charmonium production in proton-lead and lead-lead collisions with ATLAS at the LHC

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00241320; The ATLAS collaboration

    2016-01-01

    Electroweak bosons do not interact strongly with the dense and hot medium formed in nuclear collisions, and thus should be sensitive to the nuclear modification of parton distribution functions (nPDFs). The in-medium modification of heavy charmonium states plays an important role in studying the hot and dense medium. The ATLAS detector, optimized to search for new physics in proton-proton collisions, is well equipped to measure Z and W bosons as well as quarkonium in the high occupancy environment produced in heavy ion collisions. Results from the ATLAS experiment on W and Z boson yields as a function of centrality, transverse momentum and rapidity, in lead-lead and proton-lead collisions are presented. Quarkonium results from proton-lead collisions are also presented.

  6. Lead in new paints in Nepal.

    Science.gov (United States)

    Gottesfeld, Perry; Pokhrel, Dhiraj; Pokhrel, Amod K

    2014-07-01

    Samples from 75 paint products made by 21 domestic and foreign manufacturers were purchased from retail stores in five major cities in Nepal and tested for lead content. Information provided on product labels were noted. Samples were selected to be representative of the large number of brands and colors available in retail shops. Although a majority of the products purchased were manufactured in Nepal, paints from four additional countries were tested. Out of a total of 75 samples, 57 (76%) of the tested paints contained lead at concentrations greater than 90 ppm (ppm). Ninety-three percent of the paints that exceeded 90 ppm had levels in excess of 600 ppm. Lead concentrations in the tested paints ranged up to 200,000 ppm (20%) lead by weight and the median concentration was 5100 ppm. These results indicate that lead paint is commonly being sold for residential and other consumer applications in Nepal without any consumer warnings. Regulations are needed to specify the maximum concentration of lead allowed in paint products manufactured, imported, or distributed in the country to protect public health. Efforts must be made to get lead-containing paint products recalled from stores so that they are not used in homes, schools, and other child-occupied facilities. Copyright © 2014 Elsevier Inc. All rights reserved.

  7. Lead-acid batteries with foam grids

    Science.gov (United States)

    Tabaatabaai, S. M.; Rahmanifar, M. S.; Mousavi, S. A.; Shekofteh, S.; Khonsari, Jh.; Oweisi, A.; Hejabi, M.; Tabrizi, H.; Shirzadi, S.; Cheraghi, B.

    Conventional lead-acid batteries are relatively heavy and thus have a low specific energy. Therefore, to improve the energy density, a lighter grid has been proposed. In this work, a novel lead-acid battery with high specific surface area negative foam current collectors was designed and constructed. The collectors were studied by cyclic voltametery (CV) and electrochemical impedance spectroscopy (EIS). The foam collectors were designed and suitable paste composition and formation algorithm was obtained. The basic cells were manufactured and its performance was evaluated. The results showed that the foam grids resistance was lower than that for lead grids and the specific surface area of the foam grids was very greater than lead grids. The foam battery has good discharge characteristics compared with common lead-acid batteries. The discharge curve was flat and negative mass utilization efficiency was higher than 50% when the cell was discharged with C5/5 A (137 Ah kg -1 negative active materials). The foam grids were used as negative electrode for various types of lead-acid batteries such as 60 Ah starter battery, 2, 3 and 10 Ah VRLA batteries. The batteries with foam grids were shown longer cycle life than conventional lead-acid batteries.

  8. Lead poisoning and brain cell function

    Energy Technology Data Exchange (ETDEWEB)

    Goldstein, G.W. (Johns Hopkins School of Medicine, Baltimore, MD (USA) Kennedy Institute, Baltimore, MD (USA))

    1990-11-01

    Exposure to excessive amounts of inorganic lead during the toddler years may produce lasting adverse effects upon brain function. Maximal ingestion of lead occurs at an age when major changes are occurring in the density of brain synaptic connections. The developmental reorganization of synapses is, in part, mediated by protein kinases, and these enzymes are particularly sensitive to stimulation by lead. By inappropriately activating specific protein kinases, lead poisoning may disrupt the development of neural networks without producing overt pathological alterations. The blood-brain barrier is another potential vulnerable site for the neurotoxic action of lead. protein kinases appear to regulate the development of brain capillaries and the expression of the blood-brain barrier properties. Stimulation of protein kinase by lead may disrupt barrier development and alter the precise regulation of the neuronal environment that is required for normal brain function. Together, these findings suggest that the sensitivity of protein kinases to lead may in part underlie the brain dysfunction observed in children poisoned by this toxicant.

  9. Biological fractionation of lead isotopes in Sprague-Dawley rats lead poisoned via the respiratory tract.

    Science.gov (United States)

    Wu, Jing; Liu, Duojian; Xie, Qing; Wang, Jingyu

    2012-01-01

    It was considered that lead isotope ratios did not change during physical, chemical, or biological processes. Thus, lead isotope ratios have been used as fingerprints to identify possible lead sources. However, recent evidence has shown that the lead isotope ratios among different biological samples in human are not always identical from its lead origins in vitro. An animal experiment was conducted to explore the biological fractionation of lead isotopes in biological systems. 24 male Sprague-Dawley (SD) rats were divided into groups that received acute lead exposure (0, 0.02, 0.2, or 2 mg/kg body weight of lead acetate) via the respiratory route every day for 5 days. Biological samples (i.e., blood, urine, and feces) were collected for comparison with the lead acetate (test substance) and the low-lead animal feed (diet) administered to the rats. The lead isotope ratios were determined by inductively coupled plasma mass spectrometry (ICP-MS). There are significant differences (pisotope ratios between blood, urine, and feces. Moreover, a nonlinear relationship between the blood lead concentration and the blood lead isotope ratios was observed. There is also a threshold effect to the fractionation function. Only the blood isotope ratio of (204)Pb/(206)Pb matches the test substance well. As for feces, when (204)Pb/(206)Pb ratio is considered, there is no significant difference between feces-test substance pairs in medium and high dose group. The biological fractionation of lead isotopes in SD rats was observed. Moreover, there might be a threshold for the biological fractionation of lead isotopes which is depending on whole blood lead level. It is considered to be more reliable that we compared the isotope ratios of potential lead hazards with both blood and feces lead fingerprints especially for (204)Pb/(206)Pb ratio under high-dose exposure.

  10. A Case of Brugada Pattern Migrant from Right Precordial Leads to Peripheral Leads.

    Science.gov (United States)

    Luzza, Francesco; Crea, Pasquale; Nicotera, Angela; Picciolo, Giuseppe; Pugliatti, Pietro; Oreto, Giuseppe

    2016-05-01

    Since the first report in 1992, Brugada pattern (BP) diagnosis is mainly based on analysis of the precordial leads. In cases with no clear BP evidence in the conventional right precordial leads (4th intercostal space), limb leads analysis resulted helpful in suspecting BP. Fluctuations within right precordial leads between the diagnostic ECG pattern and nondiagnostic ECGs are well known. For the first time, in the patient herewith reported, the transformation of BP phenotype involves both precordial and peripheral leads, confirming that the analysis of all the 12 leads has a key role in BP diagnosis. © 2015 Wiley Periodicals, Inc.

  11. Acute Lead Poisoning In an Infant

    OpenAIRE

    Madhusudhanan, M.; Lall, S.B.

    2007-01-01

    A case of acute lead poisoning in an infant without overt clinical manifestations of encephalopathy is reported for the first time in Oman. The case was diagnosed at Rustaq Hospital on the basis of (i) history by the mother of giving the child a traditional remedy for treating constipation (ii) X-ray of abdomen showing radio-opaque speckles and (iii) detection of high blood lead levels (83.3 µg/dL) at the toxicology laboratory of the poison control centre. The source of lead was confirmed by ...

  12. Lead hepatotoxicity: Selected aspects of pathobiochemistry

    Directory of Open Access Journals (Sweden)

    Mateusz Labudda

    2013-08-01

    Full Text Available Lead (Pb that belongs to heavy metals is one of the major pollution components of the environment. Occupational and environmental exposure to lead can cause its absorption by the body and consequently exert toxic effects in the liver. In this paper biochemical determinants of hepatotoxicity caused by lead are presented. Generation of reactive oxygen species, disturbances in the cellular antioxidant system, lipid peroxidation, inhibition of enzymatic proteins and intercellular signaling are also discussed. Med Pr 2013;64(4:565–568

  13. Suspected lead toxicosis in a bald eagle

    Science.gov (United States)

    Jacobson, E.; Carpenter, J.W.; Novilla, M.

    1977-01-01

    An immature bald eagle (Haliaeetus leucocephalus) was submitted to the University of Maryland, College Park, for clinical examination. The bird was thin, had green watery feces, and was unable to maintain itself in upright posture. Following radiography, the bird went into respiratory distress and died. Numerous lead shot were recovered from the gizzard, and chemical analysis of liver and kidney tissue revealed 22.9 and 11.3 ppm lead, respectively. The clinical signs, necropsy findings, and chemical analysis of the eagle were compatible with lead toxicosis.

  14. OSHA issues new guidelines on lead.

    Science.gov (United States)

    1979-12-07

    The OSHA (Occupational Safety and Health Administration) issued new lead exposure standards which were effective February 1979. The policy provides that workers in childbearing years should receive protected earnings and benefits for 18 months while temporarily removed from their regular job to one with less lead exposure. Excessive lead exposure can reduce sex drive, cause impotence and sterility in men, and cause reduced fertility and menstrual disorders in women. Children of exposed parents may have birth defects, mental retardation, or die in their first year.

  15. Pb Neurotoxicity: Neuropsychological Effects of Lead Toxicity

    Directory of Open Access Journals (Sweden)

    Lisa H. Mason

    2014-01-01

    Full Text Available Neurotoxicity is a term used to describe neurophysiological changes caused by exposure to toxic agents. Such exposure can result in neurocognitive symptoms and/or psychiatric disturbances. Common toxic agents include heavy metals, drugs, organophosphates, bacterial, and animal neurotoxins. Among heavy metal exposures, lead exposure is one of the most common exposures that can lead to significant neuropsychological and functional decline in humans. In this review, neurotoxic lead exposure's pathophysiology, etiology, and epidemiology are explored. In addition, commonly associated neuropsychological difficulties in intelligence, memory, executive functioning, attention, processing speed, language, visuospatial skills, motor skills, and affect/mood are explored.

  16. Mission-Area Guide to Lead-Exposure Control

    Science.gov (United States)

    1996-03-01

    Lead-Exposure Control March 1996 63 DOD Memorandum, SUBJECT: Modification of Pediatric Blood Lead Screening Program, June 26, 1995. Universal...contain lead compounds in dyes (lead acetate, lead dioxide, lead chromate, and lead nitrate) and in coatings (waterproof fabric contains lead resinate ...resistance to corrosion, and biocompatibility. Dental materials containing metals and metal alloys include amalgams, impressions, fillings, crowns

  17. Distribution of lead in human milk fractions: relationship with essential minerals and maternal blood lead.

    Science.gov (United States)

    Anastácio, Alexandra da Silva; da Silveira, Carmem Lucia Porto; Miekeley, Norbert; Donangelo, Carmen Marino

    2004-01-01

    The purpose of this study was to determine the concentration and distribution of lead, calcium, iron, zinc, and copper in major fractions (fat, casein, whey) of mature milk from 38 nursing adult women with low environmental lead exposure. The potential associations between milk lead and maternal blood lead and between milk and blood lead and essential mineral data (nutritional status, dietary intake, and milk concentration) were investigated. Maternal blood lead (geometric mean, 60 microg/L) was negatively associated, although modestly, with dietary calcium intake (r=-0.32, p=0.02). Lead in whole milk (geometric mean, 1.2 microg/L) was positively associated with calcium in whole milk (r=0.56, p=0.005). Distribution of lead in milk fractions was 63%, 28%, and 9%, in whey, fat, and casein, respectively. Milk distribution of essential minerals was 67-76%, 17-18%, and 7-17% in whey, fat, and casein, respectively. Lead in milk whey was positively associated with lead in maternal blood (r=0.49, p=0.02). However, milk lead was not affected by nutritional status, dietary intake, and milk composition of the essential minerals. The high percentage of lead in the milk whey fraction, as seen for the essential minerals, suggests that most lead in human milk is bioavailable to the infant.

  18. Lead identification in soil surrounding a used lead acid battery smelter area in Banten, Indonesia

    Science.gov (United States)

    Adventini, N.; Santoso, M.; Lestiani, D. D.; Syahfitri, W. Y. N.; Rixson, L.

    2017-06-01

    A used lead acid battery smelter generates particulates containing lead that can contaminate the surrounding environment area. Lead is a heavy metal which is harmful to health if it enters the human body through soil, air, or water. An identification of lead in soil samples surrounding formal and informal used lead acid battery smelters area in Banten, Indonesia using EDXRF has been carried out. The EDXRF accuracy and precision evaluated from marine sediment IAEA 457 gave a good agreement to the certified value. A number of 16 soil samples from formal and informal areas and 2 soil samples from control area were taken from surface and subsurface soils. The highest lead concentrations from both lead smelter were approximately 9 folds and 11 folds higher than the reference and control samples. The assessment of lead contamination in soils described in Cf index was in category: moderately and strongly polluted by lead for formal and informal lead smelter. Daily lead intake of children in this study from all sites had exceeded the recommended dietary allowance. The HI values for adults and children living near both lead smelter areas were greater than the value of safety threshold 1. This study finding confirmed that there is a potential health risk for inhabitants surrounding the used lead acid battery smelter areas in Banten, Indonesia.

  19. Coronary Sinus Lead Removal: A Comparison between Active and Passive Fixation Leads.

    Science.gov (United States)

    Pecha, Simon; Kennergren, Charles; Yildirim, Yalin; Gosau, Nils; Aydin, Ali; Willems, Stephan; Treede, Hendrik; Reichenspurner, Hermann; Hakmi, Samer

    2016-01-01

    Implantation of coronary sinus (CS) leads may be a difficult procedure due to different vein anatomies and a possible lead dislodgement. The mode of CS lead fixation has changed and developed in recent years. We compared the removal procedures of active and passive fixation leads. Between January 2009 and January 2014, 22 patients at our centre underwent CS lead removal, 6 active and 16 passive fixation leads were attempted using simple traction or lead locking devices with or without laser extraction sheaths. Data on procedural variables and success rates were collected and retrospectively analyzed. The mean patient age was 67.2 ± 9.8 years, and 90.9% were male. The indication for lead removal was infection in all cases. All active fixation leads were Medtronic® Attain StarFix™ Model 4195 (Medtronic Inc., Minneapolis, MN, USA). The mean time from implantation for the active and passive fixation leads was 9.9 ± 11.7 months (range 1.0-30.1) and 48.7 ± 33.6 months (range 5.7-106.4), respectively (p = 0.012). Only 3 of 6 StarFix leads were successfully removed (50%) compared to 16 of 16 (100%) of the passive fixation CS leads (p = 0.013). No death or complications occurred during the 30-day follow-up. According to our experience, removal of the Starfix active fixation CS leads had a higher procedural failure rate compared to passive.

  20. NCHS - Leading Causes of Death: United States

    Data.gov (United States)

    U.S. Department of Health & Human Services — This dataset presents the age-adjusted death rates for the 10 leading causes of death in the United States beginning in 1999. Data are based on information from all...

  1. Mining, habitats lead space architecture work

    National Research Council Canada - National Science Library

    David Nixon

    2013-01-01

      Nixon narrates how space mining habitats lead space architecture work. NASA's current focus on an asteroid rendezvous mission as human space exploration's next big goal has begun to stimulate ideas from the space community at large...

  2. NIH Research Leads to Cervical Cancer Vaccine

    Science.gov (United States)

    ... Transmitted Diseases NIH Research Leads to Cervical Cancer Vaccine Past Issues / Fall 2008 Table of Contents For ... Douglas Lowy (left) and John Schiller developed the vaccine to prevent HPV infection in women, the cause ...

  3. The Earliest Lead Object in the Levant.

    Directory of Open Access Journals (Sweden)

    Naama Yahalom-Mack

    Full Text Available In the deepest section of a large complex cave in the northern Negev desert, Israel, a bi-conical lead object was found logged onto a wooden shaft. Associated material remains and radiocarbon dating of the shaft place the object within the Late Chalcolithic period, at the late 5th millennium BCE. Based on chemical and lead isotope analysis, we show that this unique object was made of almost pure metallic lead, likely smelted from lead ores originating in the Taurus range in Anatolia. Either the finished object, or the raw material, was brought to the southern Levant, adding another major component to the already-rich Late Chalcolithic metallurgical corpus known to-date. The paper also discusses possible uses of the object, suggesting that it may have been used as a spindle whorl, at least towards its deposition.

  4. Loneliness May Lead to Sleepless Nights

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_166146.html Loneliness May Lead to Sleepless Nights Study suggests that ... 1, 2017 THURSDAY, June 1, 2017 (HealthDay News) -- Loneliness may rob you of your sleep, British researchers ...

  5. Current practice in transvenous lead extraction

    DEFF Research Database (Denmark)

    Bongiorni, Maria Grazia; Blomström-Lundqvist, Carina; Kennergren, Charles

    2012-01-01

    AIM: Current practice with regard to transvenous lead extraction among European implanting centres was analysed by this survey. METHODS AND RESULTS: Among all contacted centres, 164, from 30 countries, declared that they perform transvenous lead extraction and answered 58 questions...... with a compliance rate of 99.9%. Data from the survey show that there seems to be an overall increasing experience of managing various techniques of lead extraction and a widespread involvement of cardiac centres in this treatment. Results and complication rates seem comparable with those of main international...... registries. CONCLUSION: This survey gives an interesting snapshot of lead extraction in Europe today and gives some clues for future research and prospective European registries....

  6. Environmental lead exposure increases micronuclei in children

    DEFF Research Database (Denmark)

    Kapka, Lucyna; Baumgartner, Adolf; Siwińska, Ewa

    2007-01-01

    The objective of this pilot study was to investigate the contribution of environmental exposures to lead in the development of cytogenetic damage detected as the frequency of micronuclei (MN) in children. The other aim was to apply the MN assay in combination with fluorescence in situ hybridization...... age from an unexposed recreational area. Exposure to lead was assessed by determination of lead concentrations in blood (PbB) by atomic absorption spectrophotometry, whereas the level of selenium (Se) in serum was detected by using graphite furnace atomic-absorption spectrometry. The frequency of MN...... was determined by the cytokinesis-block MN assay and fluorescence in situ hybridization performed using a specific pan-centromeric probe. Environmental exposure to lead resulted in significantly increased levels of PbB (5.29 +/- 2.09 versus 3.45 +/- 1.20 microg/dl in controls), although the average level...

  7. Asymptomatic congenital lead poisoning - case report.

    Science.gov (United States)

    Chinnakaruppan, Nachammai R; Marcus, Steven Matthew

    2010-07-01

    Congenital lead poisoning is uncommon and there is no consensus on the management of the newborn. A female infant was born to a lead-burdened woman identified by screening just prior to delivery. Maternal blood lead level (BLL) was 58 μg/dL. The infant's BLL on the second day of life was 72 μg/dL with a free erythrocyte protoporphyrin level of 175 μg/dL. The child was managed by an exchange transfusion followed by chelation. The BLL 6 h after exchange transfusion was 11.4 μg/dL. Follow-up 2 years later showed a BLL of 9 μg/dL and normal development. We present the details of a case of congenital lead poisoning treated aggressively which appears to have resulted in a favorable outcome.

  8. Ayurvedic herbal medicine and lead poisoning.

    Science.gov (United States)

    Gunturu, Krishna S; Nagarajan, Priyadharsini; McPhedran, Peter; Goodman, Thomas R; Hodsdon, Michael E; Strout, Matthew P

    2011-12-20

    Although the majority of published cases of lead poisoning come from occupational exposures, some traditional remedies may also contain toxic amounts of lead. Ayurveda is a system of traditional medicine that is native to India and is used in many parts of world as an alternative to standard treatment regimens. Here, we report the case of a 58-year-old woman who presented with abdominal pain, anemia, liver function abnormalities, and an elevated blood lead level. The patient was found to have been taking the Ayurvedic medicine Jambrulin prior to presentation. Chemical analysis of the medication showed high levels of lead. Following treatment with an oral chelating agent, the patient's symptoms resolved and laboratory abnormalities normalized. This case highlights the need for increased awareness that some Ayurvedic medicines may contain potentially harmful levels of heavy metals and people who use them are at risk of developing associated toxicities.

  9. Ayurvedic herbal medicine and lead poisoning

    Directory of Open Access Journals (Sweden)

    Gunturu Krishna S

    2011-12-01

    Full Text Available Abstract Although the majority of published cases of lead poisoning come from occupational exposures, some traditional remedies may also contain toxic amounts of lead. Ayurveda is a system of traditional medicine that is native to India and is used in many parts of world as an alternative to standard treatment regimens. Here, we report the case of a 58-year-old woman who presented with abdominal pain, anemia, liver function abnormalities, and an elevated blood lead level. The patient was found to have been taking the Ayurvedic medicine Jambrulin prior to presentation. Chemical analysis of the medication showed high levels of lead. Following treatment with an oral chelating agent, the patient's symptoms resolved and laboratory abnormalities normalized. This case highlights the need for increased awareness that some Ayurvedic medicines may contain potentially harmful levels of heavy metals and people who use them are at risk of developing associated toxicities.

  10. How lead loses its toxicity to plants

    National Research Council Canada - National Science Library

    Małgorzata Wierzbicka

    2014-01-01

    .... This surprising result is in agreement with the absence of any symptoms of lead poisoning in plants growing in natural conditions, and suggests that there is a defence mechanism specific only for plant cells.

  11. Treating Lead Toxicity: Possibilities beyond Synthetic Chelation

    Directory of Open Access Journals (Sweden)

    Shambhavi Tannir

    2013-01-01

    Full Text Available Lead, a ubiquitous metal, is one of the most abundant elements present on earth. Its easy availability and cost effectiveness made it an extremely popular component in the industrial revolution. However, its hazardous health effects were not considered at the time. Over the last few decades, with the adverse effects of lead coming to the forefront, nations across the world have started to recognize and treat lead toxicity. The most reliable and used method until now has been chelation therapy. Recent research has suggested the use of natural products and sources to treat lead poisoning with minimal or no side effects. This review has tried to summarize a few of the natural products/sources being investigated by various groups.

  12. FastStats: Leading Causes of Death

    Science.gov (United States)

    ... Chronic Sinusitis Whooping Cough or Pertussis Family Life Marriage and Divorce Health Care and Insurance Access to ... Cause of Death Contribute to the Hispanic Mortality Advantage in the United States? Leading Causes of Death ...

  13. Lead State Implementation Plan (SIP) Checklist Guide

    Science.gov (United States)

    Guidance documents and examples to assist air quality agencies of non-attainment areas in developing plans to implement national ambient air quality standards (NAAQS), including the lead air emissions standard.

  14. Effects of lead on plant growth

    Energy Technology Data Exchange (ETDEWEB)

    Fiussello, N.; Molinari, M.T.

    1973-01-01

    The poisonousness of lead nitrate to seedlings of several plant species has been tested in Petri dishes, with 10/sup -1/, 10/sup -2/, 10/sup -3/, 10/sup -4/ M conc. Distilled water and KNO/sub 3/ solutions 2 X 10/sup -1/, 2 X 10/sup -2/, 2 X 10/sup -3/, 2 X 10/sup -4/ M were employed as controls. The tested species show a decreasing sensitivity: Capsicum annum > Beta vulgaris > Phalaris canariensis > Vicia sativa > Helianthus annuus > Oryza sativa > Triticum vulgare Avena sativa > Pisum sativum. Avena sativa shows a diminution of 34% in ww, 23% in dw, 26% in chlorophyll content in comparison with the controls after 21 days 10/sup -4/ M lead nitrate. The chlorophyll content, referred to dry weight, is related to lead concentration. Since the early stages of chlorophyll biosynthesis are similar, if not identical, with those for Haemoglobin, lead could interfere as it does in haemoglobin synthesis.

  15. Lead sulphate leaching by sodium chloride solution

    National Research Council Canada - National Science Library

    Conić Vesna T; Pešovski Branka D; Cvetkovski Vladimir B; Stanojević-Šimšić Zdenka S; Dragulović Suzana S; Simonović Danijela B; Dimitrijević Silvana B

    2013-01-01

    Bioleaching treatment of complex multi-metallic Cu-Zn-Pb-Ag-Au mineral concentrates leds to the formation, besides easily soluble zinc and cooper sulphates, of hardly soluble lead (II) sulfate (PbSO4) sludge...

  16. Superconducting Current Leads for Cryogenic Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Space flight cryocoolers will be able to handle limited heat loads at their expected operating temperatures and the current leads may be the dominant contributor to...

  17. Distribution of Lead in Kerbside Soils

    African Journals Online (AJOL)

    NJD

    Leaded petrol was used on a large scale at the time this study was being carried out. The toxicity of lead to .... 2.4. Calibration of AAS, ICP-AES and GF-AAS. A multi-point calibration was used to optimize and calibrate ... calibration line obtained by plotting the data obtained. The same procedure was used for the other two ...

  18. Letting the Data Lead the Code

    Science.gov (United States)

    2015-08-01

    UNCLASSIFIED Page 1 of 4 UNCLASSIFIED: Distribution Statement A. Approved for public release. Letting the Data Lead the Code Darryl Bryk...31 AUG 2015 2. REPORT TYPE 3. DATES COVERED 00-00-2015 to 00-00-2015 4. TITLE AND SUBTITLE Letting the Data Lead the Code 5a. CONTRACT NUMBER...int.TryParse(s[i], out inum)) ilist.Add(inum

  19. Renovate Right: Prevent Lead Poisoning in Children

    Centers for Disease Control (CDC) Podcasts

    2008-10-02

    In this podcast, Dr. Maria Doa, Director of the Environmental Protection Agency's (EPA) National Program Chemicals Division, discusses EPA's new rule for renovations, repairs, and painting activities. The new rule includes information on lead-safe work practices when conducting renovations, repairs, and painting in pre-1978 homes and schools to prevent the spread of lead dust.  Created: 10/2/2008 by National Center for Environmental Health (NCEH).   Date Released: 10/2/2008.

  20. Lead Toxicity Risks in Gunshot Victims.

    Directory of Open Access Journals (Sweden)

    Gabriel Costa Serrão de Araújo

    Full Text Available Gunshot wounds require surgeons to decide whether to remove or leave bullet fragments in the body. Surgeons also decide how to follow up with patients who have lead fragments retained in their body. Current literature recommends to remove only intra-articular fragments without the need for a follow-up for patients with the metal retained. Therefore, this study investigates chronic lead toxicity for gunshot wounds.The study was performed in the metropolitan area of Rio de Janeiro/Brazil, between 2013 and 2015. It was a case-control study that included 45 victims of gunshot lesions with metallic fragments retained for more than 6 months. The 45 controls were matched for gender, age, and race. We compared the lead blood levels and frequency of symptoms.The control group had average blood lead levels of 2.17 μg/dL (95% Confidence Interval [CI]; 1.71-2.63 and median 2.1 μg/dL. The case group had average values of 9.01 μg/dL (CI; 6.07-11.96 and median values of 6.5 μg/dL with p-values < = 0.001. The case group reported the following more frequently: irritancy, bad mood, headache, memory losses, daylight drowsiness, myalgia, weakness, abdominal pain, joint pain, trembling, tingling limbs. There was statistical significance for the differences of symptoms frequencies and for odds ratio between groups.Although the mean lead levels found were lower than the current laboratory references, low levels have been associated with both rising morbidity and mortality. The WHO stated: "There is no known level of lead exposure that is considered safe". In conclusion, this work showed that bullets retained in the body are not innocuous. There are impacts in the blood lead levels and symptoms related to it, even with few fragments, extra-articular located or existing with low blood lead levels.

  1. Oral lead exposure induces dysbacteriosis in rats.

    Science.gov (United States)

    Sadykov, Rustam; Digel, Ilya; Artmann, Aysegül Temiz; Porst, Dariusz; Linder, Peter; Kayser, Peter; Artmann, Gerhard; Savitskaya, Irina; Zhubanova, Azhar

    2009-01-01

    Lead's (Pb(II)) possible role in intestinal pathologies of microbial etiology remains mostly unknown. The aim of this study was to examine the effects of lead on the gut microbial community and its interactions with rat intestinal epithelium. The lead-induced changes in different intestinal microbial groups (lactose-positive lac(+) and -negative lac(-) E.coli strains, lactobacilli and yeasts) were followed separately by the colony-forming unit (CFU) method. Samples were taken from outbred white rats subjected to different exposure schedules. Additionally, the impact of different lead doses on microbial adhesion to cultured intestinal cells (IEC-6) was investigated. Finally, the lead accumulation and distribution were measured by means of atomic absorption spectrometry. For the first time it was shown that oral lead exposure causes drastic changes in the gut microbial community. Proportional to the lead dose received, the relative number of lactose-negative E.coli cells increased dramatically (up to 1,000-fold) in comparison to the other microbial groups during 2 wk of exposure. Considering the number of microbes in the intestine, such a shift in intestinal microflora (dysbacteriosis) is very significant. Adhesion studies showed certain stimulating effects of lead on E. coli attachment to rat intestinal epithelium as compared to Lactobacillus attachment. The mechanisms providing the apparent competitive success of the lac(-) group are unclear but could be related to changes in surface interactions between microbial and host cells. This study may provide important clues for understanding the pathological effects of metal dietary toxins in human beings.

  2. EPA Leads the Way on Lead Exposure Science and Risk Management

    Science.gov (United States)

    EPA researchers have developed a modeling approach that improves our understanding of the relationship between lead concentrations of various sources (drinking water, soil and dust, food, and air) and children’s blood-lead levels.

  3. Corrosion by liquid lead and lead-bismuth: experimental results review and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Jinsuo [Los Alamos National Laboratory

    2008-01-01

    Liquid metal technologies for liquid lead and lead-bismuth alloy are under wide investigation and development for advanced nuclear energy systems and waste transmutation systems. Material corrosion is one of the main issues studied a lot recently in the development of the liquid metal technology. This study reviews corrosion by liquid lead and lead bismuth, including the corrosion mechanisms, corrosion inhibitor and the formation of the protective oxide layer. The available experimental data are analyzed by using a corrosion model in which the oxidation and scale removal are coupled. Based on the model, long-term behaviors of steels in liquid lead and lead-bismuth are predictable. This report provides information for the selection of structural materials for typical nuclear reactor coolant systems when selecting liquid lead or lead bismuth as heat transfer media.

  4. [Environmental lead poisoning from lead-glazed earthenware used for storing drinks].

    Science.gov (United States)

    Sabouraud, S; Coppéré, B; Rousseau, C; Testud, F; Pulce, C; Tholly, F; Blanc, M; Culoma, F; Facchin, A; Ninet, J; Chambon, P; Medina, B; Descotes, J

    2009-12-01

    Current unusual environmental sources of lead exposure mainly include traditional medicines, either ayurvedic remedies or others, traditional cosmetics (kohl, surma), and the use of traditional earthenware, for storage or cooking. We report two cases of lead poisoning in adults initially identified by paroxysmal abdominal pain or anemia. In both cases, the environmental investigation evidenced one main source of lead exposure, namely a lead-glazed earthenware jug in which a drink was stored, "kefir" in the first case, and "kombucha" tea in the second one. It is recommended to search for lead intoxication in patients with unexplained anemia. Environmental sources of lead can be multiple. Their relative importance has to be ranked during the environmental investigation and among these, lead-glazed earthenware must be considered as a source of high lead exposure when drinks are stored inside and thus can soak.

  5. Investigations on organolead compounds V. Lead---lead bond cleavage reactions of hexaphenyldilead

    NARCIS (Netherlands)

    Willemsens, L.C.; Kerk, G.J.M. van der

    1968-01-01

    It has been shown that a number of nucleophilic and weakly electrophilic reagents (organolithium and organomagnesium compounds, metallic lithium, potassium permanganate, sodium ethoxide, diaryl disulphides, sulphur, ozone, hypochlorous acid and iodine/iodide) selectively cleave the lead---lead bond

  6. Acute lead poisoning in an infant.

    Science.gov (United States)

    Madhusudhanan, M; Lall, S B

    2007-10-01

    A case of acute lead poisoning in an infant without overt clinical manifestations of encephalopathy is reported for the first time in Oman. The case was diagnosed at Rustaq Hospital on the basis of (i) history by the mother of giving the child a traditional remedy for treating constipation (ii) X-ray of abdomen showing radio-opaque speckles and (iii) detection of high blood lead levels (83.3 µg/dL) at the toxicology laboratory of the poison control centre. The source of lead was confirmed by high content of inorganic lead (20.2%) found in the sample of the traditional remedy (bint al dahab). The blood lead levels significantly decreased, after the intravenous calcium edetate (EDTA) therapy was given to the baby. The case highlights that early detection and treatment of acute lead poisoning in children can prevent morbidity and sequelae associated with encephalopathy. It also indicated the need for awareness and prevention programme for parents on this issue.

  7. Environmentally sound technologies for recycling secondary lead

    Science.gov (United States)

    Andrews, D.; Raychaudhuri, A.; Frias, C.

    Advances in hydrometallurgy are providing increasingly simple means for controlling the entire lead chain from concentrate to recycled lead. Used in parallel with pyrometallurgy, these processes allow furnace temperatures to be reduced to the minimum, which is essential for casting or alloying. Fumes and atmospheric pollution are minimized, furnace slags are digested, and most residues (other than purification cements) are non-toxic and convertible into marketable products. These new processes provide the cleanest and healthiest practicable means for recycling lead from batteries. By substituting melting for smelting, the heat requirement and cycle time per charge are reduced by more than half. A new hydrometallurgical plant could be installed alongside an existing pyrometallurgical plant without interference, doubling its potential capacity when operational (and more, if electrowinning is used). Over 99.5% of the lead originally present is recovered in tests of a combined PLACID-pyro plant. The average purity of electrowon PLACID lead is 99.995%. Results from the PLINT process should be similar. The purity of the lead chain can thereby be sustained through recycling. Perfect solid/paste separation is not mandatory, and PLINT-type plant units can be of any size. Such processes constitute a good basis for development of clean processes, which are suitable for use in Asian societies.

  8. Blood lead levels and chronic blood loss

    Energy Technology Data Exchange (ETDEWEB)

    Manci, E.A.; Cabaniss, M.L.; Boerth, R.C.; Blackburn, W.R.

    1986-03-01

    Over 90% of lead in blood is bound to the erythrocytes. This high affinity of lead for red cells may mean that chronic blood loss is a significant means for excretion of lead. This study sought correlations between blood lead levels and clinical conditions involving chronic blood loss. During May, June and July, 146 patients with normal hematocrits and red cell indices were identified from the hospital and clinic populations. For each patient, age, race, sex and medical history were noted, and a whole blood sample was analyzed by flameless atomic absorption spectrophotometry. Age-and race-matched pairs showed a significant correlation of chronic blood loss with lead levels. Patients with the longest history of blood loss (menstruating women) had the lowest level (mean 6.13 ..mu..g/dl, range 3.6-10.3 ..mu..g/dl). Post-menopausal women had levels (7.29 ..mu..g/dl, 1.2-14 ..mu..g/dl) comparable to men with peptic ulcer disease, or colon carcinoma (7.31 ..mu..g/dl, 5.3-8.6 ..mu..g/dl). The highest levels were among men who had no history of bleeding problems (12.39 ..mu..g/dl, 2.08-39.35 ..mu..g/dl). Chronic blood loss may be a major factor responsible for sexual differences in blood lead levels. Since tissue deposition of environmental pollutants is implicated in diseases, menstruation may represent a survival advantage for women.

  9. Lead exposure assessment from study near a lead-acid battery factory in China.

    Science.gov (United States)

    Chen, Laiguo; Xu, Zhencheng; Liu, Ming; Huang, Yumei; Fan, Ruifang; Su, Yanhua; Hu, Guocheng; Peng, Xiaowu; Peng, Xiaochun

    2012-07-01

    The production of lead-acid battery in China covered about one-third of the world total output and there are more than 2000 lead-acid battery factories. They may cause the major environment lead pollution. Blood lead levels of several hundreds of residents were over 100 μg/L due to the waste discharges from a lead-acid battery factory in Heyuan, Guangdong province. This study aimed to find out the environmental lead sources, the human lead exposure pathways, and the amplitudes from a lead-acid battery factory. The study results showed that lead levels in soil, dust, tree leaves and human blood declined with the distances increased from the production site. Twenty nine of 32 participants had blood lead levels of over 100 μg/L with an exceptional high value of 639 μg/L for one child. This result suggested that the lead-acid battery production from this factory has caused the elevated lead levels in its neighboring environment and residents. Dust intake was the dominant exposure pathway for humans (over 90%). The lead levels found in adult and toddler (6.19 and 50.1 μg/kg/d, respectively) in the polluted area were far higher than the provisional tolerable weekly intake (PTWI) of 25 μg/kg body weight (translated into 3.5 μg/kg/d), which was established by the joint FAO/WHO Expert Committee. Blood lead levels within the family members were strongly correlated with the house dust lead levels. Our results in this study suggested that further studies in this area should be performed to assess human exposure and relevant human health risks from living close to lead-acid battery factories. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Extraction of chronically implanted coronary sinus leads active fixation vs passive fixation leads.

    Science.gov (United States)

    Crossley, George H; Sorrentino, Robert A; Exner, Derek V; Merliss, Andrew D; Tobias, Serge M; Martin, David O; Augostini, Ralph; Piccini, Jonathan P; Schaerf, Raymond; Li, Shelby; Miller, Clayton T; Adler, Stuart W

    2016-06-01

    The Medtronic model 4195 (StarFix) left ventricular lead is an active fixation lead that provides additional support within the coronary sinus (CS) via deployable lobes. While this lead has been shown to have excellent stability within the CS, concerns about its extractability have been raised. The aim of this study was to compare the safety and efficacy of the extraction of the model 4195 lead vs other Medtronic CS leads in a prospective cohort study. Patients undergoing extraction of this and other CS leads for standard indications were prospectively enrolled and studied. The primary outcomes of interest were the removal success rates and associated complication rates. Patients were followed for a month postprocedure. The overall left ventricular lead extraction success rate was 97.6% (n = 205). Among 40 patients with chronic model 4195 leads, there were 37 successful extractions (92.5%) as compared to 98.8% for the 165 non-4195 leads. However, in 2 of the 3 StarFix lead extraction failures, standard extraction techniques were not used. All 10 of the model 4195 leads that had been implanted for less than 6 months were extracted without incident. In this largest study of CS lead extractions published to date, the overall success rate of the extraction of chronically implanted CS leads is high and the complication rate is similar in these lead models. The extraction of the model 4195 lead is clearly more challenging, but it can be accomplished in high-volume extraction centers with experienced operators. It is recommended that the model 4195 lead be extracted by experienced operators. Copyright © 2016. Published by Elsevier Inc.

  11. Leading by example to protect the environment : Do the costs of leading matter?

    NARCIS (Netherlands)

    van der Heijden, E.C.M.; Moxnes, E.

    2013-01-01

    Environmentalists often urge their home countries to take a leading role in reducing global environmental problems like climate change. A pertinent question is, Will examples set by leading nations influence others to follow suit, and if so, do the costs of leading matter? For instance, will costly

  12. Leading by Example to Protect the Environment; Do the Costs of Leading Matter?

    NARCIS (Netherlands)

    van der Heijden, E.C.M.; Moxnes, E.

    2011-01-01

    Environmentalists often urge their home countries to take a leading role in reducing global environmental problems like climate change. A pertinent question is: will examples set by leading nations influence others to follow suit, and if so, do the costs of leading matter? For instance, will costly

  13. 75 FR 43942 - Children's Products Containing Lead; Technological Feasibility of 100 ppm for Lead Content...

    Science.gov (United States)

    2010-07-27

    ... COMMISSION Children's Products Containing Lead; Technological Feasibility of 100 ppm for Lead Content... content limit for children's products. DATES: Written comments and submissions in response to this notice... for children 12 years old and younger, the total lead content limit by weight in any part of a...

  14. Lead-Free vs Tin-Lead Reliability of Advanced Electronic Assemblies

    Science.gov (United States)

    Ghaffarian, Reza

    2005-01-01

    This presentation will provide the technical background and specific information published in literature related to reliability test, analyses, modeling, and associated issues for lead-free solder package assemblies in comparison to their tin-lead solder alloys. It also presents current understanding of lead-free thermal cycle test performance in support.

  15. Association of defects in lead chloride and lead bromide: Ionic conductivity and dielectric loss measurements

    NARCIS (Netherlands)

    Brom, W.E. van den; Schoonman, J.; Wit, J.H.W. de

    The ionic conductivity data of pure and doped lead bromide without associated defects are used in order to explain the anomalous conductivity behaviour of copper (I) bromide and lead oxide-doped lead-bromide crystals. In these crystals precipitated dopant and associated defects are present. The

  16. Do newspapers lead with lead? A content analysis of how lead health risks to children are covered.

    Science.gov (United States)

    Brittle, Christine; Zint, Michaela

    2003-06-01

    Lead poses a serious environmental health risk to young children, causing such irreversible health effects as mental retardation, stunted growth, and hearing and visual impairment. Studies suggest that various sectors of the public, including children's caregivers, are not sufficiently concerned about this risk or knowledgeable about ways of minimizing it. Because newspapers are one of the primary ways members of the public learn about risks, the authors examined the characteristics and content of 152 newspaper articles on lead to determine when coverage occurred and what information was provided. Results revealed that newspapers most often covered lead as a local news story. Few articles identified children under six years of age as the most vulnerable group or provided important information on health effects, sources of exposure, or abatement methods. The authors' recommendations focus on helping environmental health professionals work with newspaper journalists to improve the information available to the public.

  17. Environmental lead in Mexico, 1990-2002.

    Science.gov (United States)

    Flores, Julio; Albert, Lilia A

    2004-01-01

    From the data presented here, it can be concluded that despite some important progress in recent years, in particular, the phaseout of the use of lead in gas, environmental exposure to lead remains a particularly severe problem in Mexico. The lack of recent and adequate information on the presence of lead in air, dust, soil, surface waters, the marine environment, and food is noteworthy. In particular, there are no data on the presence of lead in the environment of industrial cities or in areas where mining and metallurgical activities are predominant, including their nearby environment, such as river sediments or air, and in their inhabitants. As a result, the official conclusion that the major present source of lead for Mexicans is the manufacture and use of lead-glazed ceramics, and the few official actions in this regard lack a solid basis because they rely on data from a few limited studies carried out mainly in Mexico City and its Metropolitan Zone. Although there have been few studies in Mexico on the adverse effects of long-term exposure to lead, the data provided on its presence in human milk, lungs, and bones and the results of the scant studies on its neuropsychological effects on children should be taken into consideration to establish more effective control and protective measures and to support the additional studies required to document the present situation. In particular, more studies should be carried out in lead glazed-ceramic-producing communities and on the hazards of lead to the communities established near industrial areas and along river banks. In future studies, special attention should be paid to establishing a common protocol, with adequate analytical control measures, if possible, with intercalibration of the participating laboratories; this is essential, because at present many of the available data cannot be compared or extrapolated due to their deficiencies in this regard. The situation around the only primary lead smelter in Mexico

  18. Increasing lead burden correlates with externalized cables during systematic fluoroscopic screening of Riata leads.

    Science.gov (United States)

    Moorman, Liza P; Moorman, J Randall; DiMarco, John P; Malhotra, Rohit; Darby, Andrew; Bilchick, Kenneth; Ferguson, John D; Mangrum, J Michael; Kamath, Sandeep; Mason, Pamela K

    2013-06-01

    Riata and Riata ST defibrillator leads (St. Jude Medical, Sylmar, CA, USA) have been recalled due to increased risk of insulation failure leading to externalized cables. As this mechanical failure does not necessarily correlate with electrical failure, it can be difficult to diagnose. Fluoroscopic screening can identify insulation failure. Studies have suggested that insulation failure is predominantly seen in 8-Fr, single-coil models. Our patients have exclusively dual-coil leads and a high proportion of 7-Fr leads. Fluoroscopic screening was performed in 48 patients with recalled Riata leads. Twenty-three patients had 8-Fr Riata leads and 25 patients had 7-Fr Riata ST leads. Images were recorded in at least three projections and studies were reviewed by seven attending electrophysiologists. Externalized cables were seen in ten patients (21 %), and another five patients (10 %) had abnormal cable spacing. All device interrogations showed normal parameters. Patients with abnormal leads had more leads in situ (2.5 ± 0.7 vs. 1.6 ± 0.8 leads; P = 0.002) and a higher rate of nonischemic cardiomyopathy (80 vs. 24 %; P = 0.03). There were no differences between the groups with regards to patient age, body mass index, lead age, lead parameters, or vascular access site. There was no difference with regard to lead size (P = 0.76). The Riata family of leads has a high incidence of mechanical failure, as demonstrated on fluoroscopic screening. In this study, the 7-Fr models were just as likely to mechanically fail as the 8-Fr models. Increasing lead burden and a diagnosis of nonischemic cardiomyopathy correlated with insulation failure.

  19. Childhood lead poisoning and the new Centers for Disease Control and Prevention guidelines for lead exposure.

    Science.gov (United States)

    Schnur, Julie; John, Rita Marie

    2014-05-01

    This article will give a brief history, review the latest guidelines, discuss risk factors and sources, and discuss screening, diagnosis, and management of lead poisoning in children. Additionally, the role of the nurse practitioner (NP) caring for children will be reviewed. Review of published literature on lead poisoning and the 2012 lead prevention guidelines of the Advisory Committee on Childhood Lead Poisoning Prevention (ACCLPP) of the Centers for Disease Control and Prevention (CDC). While lead poisoning levels have decreased over the past several decades, newer research has shown that even low levels of lead in the blood can have negative effects on children's intelligence and neurodevelopment. As a result, ACCLPP of the CDC issued new, stricter lead prevention guidelines in 2012. Lead exposure and lead poisoning are pediatric public health risks. Studies have shown that no level of lead is considered safe, and the emphasis has shifted to primary prevention of lead exposure. Despite the focus on primary prevention, the NP must remain vigilant in history taking, exploring risk factors, and screening children in order to assure the best possible outcome. ©2014 The Author(s) ©2014 American Association of Nurse Practitioners.

  20. Environmentally sound technologies for recycling secondary lead

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, D. [Heathlands, Rugby (United Kingdom); Raychaudhuri, A. [VKA Associates, New Delhi (India); Frias, C. [Placid Processes, R and D Centre of Tecnicas Reunidas Sierra Nevada, Madrid (Spain)

    2000-05-01

    Advances in hydrometallurgy are poviding increasingly simple means for controlling the entire lead chain from concentrate to recycled lead. Used in parallel with pyrometallurgy, these processes allow furnace temperatures to be reduced to the minimum, which is essential for casting or alloying. Fumes and atmospheric pollution are minimized, furnace slags are digested, and most residues (other than purification cements) are non-toxic and convertible into marketable products. These new processes provide the cleanest and healthiest practicable means for recycling lead from batteries. By substituting melting for smelting, the heat requirement and cycle time per charge are reduced by more than half. A new hydrometallurgical plant could be installed alongside an existing pyrometallurgical plant without interference, doubling its potential capacity when operational (and more, if electrowinning is used). Over 99.5% of the lead originally present is recovered in tests of a combined PLACID-pyro plant. The average purity of electrowon PLACID lead is 99.995%. Results from the PLINT process should be similar. The purity of the chain can thereby be sustained through recycling. Perfect solid/paste separation is not mandatory, and PLINT-type plant units can be of any size. Such processes constitute a good basis for development of clean processes, which are suitable for use in Asian societies. (orig.)

  1. Overview of Explosive Initiators

    Science.gov (United States)

    2015-11-01

    generally evolved over time. Dating back to the mid-1800s, mercury fulminate -based formulations were the most commonly used primer mixes. In the 1920s...alternate priming mixes were discovered to replace mercury fulminate , as this previous composition was found to deteriorate rapidly under tropical...Frankford Arsenal in the 1950s were based on lead styphnate, which is much more stable than mercury fulminate , and are still in widespread use today

  2. The Identification and Synthesis of Lead Apatite Minerals Formed in Lead Water Pipes

    Directory of Open Access Journals (Sweden)

    Jeremy D. Hopwood

    2016-01-01

    Full Text Available Phosphate is added to drinking water in the UK to minimise the release of lead from lead water pipes. The phosphate encourages the formation of insoluble lead apatites on the walls of the pipe. Hydroxylpyromorphite Pb5(PO43OH is the lead apatite that is most often used to model lead levels in tap water; however, its presence has not been confirmed. Our aims were to identify the lead pipe apatite and synthesise it. The synthetic mineral would then be used in future solubility studies to produce better predictions of lead levels in tap water. XRD and FTIR were used to characterise the minerals on a range of lead pipes. Pyromorphite and hydroxylpyromorphite were absent and instead a range of mixed calcium lead apatites were present. For every five lead ions in the general formula Pb5(PO43X between one and two ions were replaced with calcium and there was evidence of substitution of PO43- by either CO32- or HPO42-. Calcium lead apatites with similar unit cell dimensions to those found on lead water pipes were then synthesised. The calcium : lead ratio in these reaction mixtures was in excess of 500 : 1 and the resulting crystals were shown by TEM to be nanosized rods and flakes. The synthetic apatites that most closely resembled the unit cell dimensions of the apatites on lead water pipes were shown to be Pb3.4Ca1.3(PO43Cl0.03OH0.97, Pb3.6Ca1.2(PO43Cl0.07OH0.93, and Pb3.6Ca1.2(PO43Cl0.27OH0.73.

  3. Stable lead isotopic analyses of historic and contemporary lead contamination of San Francisco Bay estuary

    Science.gov (United States)

    Ritson, P.I.; Bouse, R.M.; Flegal, A.R.; Luoma, S.N.

    1999-01-01

    Variations in stable lead isotopic composition (240Pb, 206Pb, 207Pb, 208Pb) in three sediment cores from the San Francisco Bay estuary document temporal changes in sources of lead during the past two centuries. Sediment, with lead from natural geologic sources, and relatively homogeneous lead isotopic compositions are overlain by sediments whose isotopic compositions indicate change in the sources of lead associated with anthropogenic modification of the estuary. The first perturbations of lead isotopic composition in the cores occur in the late 1800s concordant with the beginning of industrialization around the estuary. Large isotopic shifts, toward lower 206Pb/207Pb, occur after the turn of the century in both Richardson and San Pablo Bays. A similar relationship among lead isotopic compositions and lead concentrations in both Bays suggest contamination from the same source (a lead smelter). The uppermost sediments (post 1980) of all cores also have a relatively homogenous lead isotopic composition distinct from pre-anthropogenic and recent aerosol signatures. Lead isotopic compositions of leachates from fourteen surface sediments and five marsh samples from the estuary were also analyzed. These analyses suggest that the lead isotopic signature identified in the upper horizons of the cores is spatially homogeneous among recently deposited sediments throughout the estuary. Current aerosol lead isotopic compositions [Smith, D.R., Niemeyer, S., Flegal, A.R., 1992. Lead sources to California sea otters: industrial inputs circumvent natural lead biodepletion mechanisms. Environmental Research 57, 163-175] are distinct from the isotopic compositions of the surface sediments, suggesting that the major source of lead is cycling of historically contaminated sediments back through the water column. Both the upper core sediments and surface sediments apparently derive their lead predominantly from sources internal to the estuary. These results support the idea that

  4. Effect of lead on root growth

    Directory of Open Access Journals (Sweden)

    Mouna eFAHR

    2013-06-01

    Full Text Available Lead (Pb is one of the most widespread heavy metal contaminants in soils. It is highly toxic to living organism. Pb has no biological function but can cause morphological, physiological and biochemical dysfunctions in plants. Plants have developed a wide range of tolerance mechanisms that are activated in response to lead exposure. Pb affects plants primarily through their root systems. Plant roots rapidly respond either (i by the synthesis and deposition of callose, creating a barrier that stops lead entering (ii through the uptake of large amounts of Pb and its sequestration in the vacuole accompanied by changes in root growth and branching pattern or (iii by its translocation to the aboveground parts of plant in the case of hyperaccumulators plants. Here we review the interactions of roots with the presence of Pb in the rhizosphere and the effect of Pb on the physiological and biochemical mechanisms of root development.

  5. Thermoforming plastic in lead shield construction.

    Science.gov (United States)

    Abrahams, M E; Chow, C H; Loyd, M D

    1989-09-01

    Radiation treatments using low energy X-rays or electrons frequently require a final field defining shield to be placed on the patient's skin. A custom made lead cut-out is used to provide a close fit to a particular patient's surface contours. We have developed a procedure which utilizes POLYFORM thermoplastic to obtain a negative mold of the patient instead of the traditional plaster bandage or dental impression gel. The Polyform is softened in warm water, molded carefully over the patient's surface, and is removed when "set" or hardened, usually within five minutes. Then lead sheet cut-outs can be formed within this negative. For shielding cut-outs requiring thicker lead sheet, a positive is made from dental stone using this Polyform negative. We have found this procedure to be neat, fast and comfortable for both patient and the dosimetrist.

  6. Thermoforming plastic in lead shield construction

    Energy Technology Data Exchange (ETDEWEB)

    Abrahams, M.E.; Chow, C.H.; Loyd, M.D. (Univ. of Texas Medical Branch, Galveston (USA))

    1989-09-01

    Radiation treatments using low energy X-rays or electrons frequently require a final field defining shield to be placed on the patient's skin. A custom made lead cut-out is used to provide a close fit to a particular patient's surface contours. We have developed a procedure which utilizes POLYFORM thermoplastic to obtain a negative mold of the patient instead of the traditional plaster bandage or dental impression gel. The Polyform is softened in warm water, molded carefully over the patient's surface, and is removed when set or hardened, usually within five minutes. Then lead sheet cut-outs can be formed within this negative. For shielding cut-outs requiring thicker lead sheet, a positive is made from dental stone using this Polyform negative. We have found this procedure to be neat, fast and comfortable for both patient and the dosimetrist.

  7. Industrial dynamics beyond the lead firms

    DEFF Research Database (Denmark)

    Haakonsson, Stine Jessen; Slepniov, Dmitrij

    Since the turn of the millennium, China has developed into a core location for the wind energy industry and is today the largest market for wind turbines. These developments have caught attention among scholars. However, most research is on the development of the market and the lead firm strategies...... for market access or on innovation, capability building and technology transfer in the industry. The main objective of this paper is to look ‘beyond the lead firms’. We seek to advance the understanding of how the recent changes in the industry affect producers of key components and their role...... in the industry. The paper employs a qualitative methodology, which draws on explorative case studies of sub-suppliers in the wind turbine industry in China. A special empirical focus is on the first tier sub-suppliers. As the Western lead firms establish themselves in China, the sub-suppliers also have...

  8. Leading-edge vortex lifts swifts.

    Science.gov (United States)

    Videler, J J; Stamhuis, E J; Povel, G D E

    2004-12-10

    The current understanding of how birds fly must be revised, because birds use their hand-wings in an unconventional way to generate lift and drag. Physical models of a common swift wing in gliding posture with a 60 degrees sweep of the sharp hand-wing leading edge were tested in a water tunnel. Interactions with the flow were measured quantitatively with digital particle image velocimetry at Reynolds numbers realistic for the gliding flight of a swift between 3750 and 37,500. The results show that gliding swifts can generate stable leading-edge vortices at small (5 degrees to 10 degrees) angles of attack. We suggest that the flow around the arm-wings of most birds can remain conventionally attached, whereas the swept-back hand-wings generate lift with leading-edge vortices.

  9. Chemically prepared lead magnesium niobate dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    Tuttle, B.A.; Voigt, J.A.; Sipola, D.L.; Olson, W.R.; Goy, D.M.

    1998-11-01

    A chemical solution powder synthesis technique has been developed that produces first, uniform powders of lead magnesium niobate (PMN) with 60 to 80 nm crystallite size. The synthesis technique was based on the dissolution of lead acetate and alkoxide precursors in acetic acid followed by precipitation with oxalic acid/propanol solutions. Lead magnesium niobate ceramics fabricated from these chemically derived powders had smaller, more uniform grain size and higher dielectric constants than ceramics fabricated from mixed oxide powders that were processed under similar thermal conditions. Chem-prep PMN dielectrics with peak dielectric constants greater than 22,000 and polarizations in excess of 29 {micro}C/cm{sup 2} were obtained for 1,100 C firing treatments. Substantial decreases in dielectric constant and polarization were measured for chemically prepared PMN ceramics fired at lower temperatures, consistent with previous work on mixed oxide materials.

  10. Investigation of Multicomponent Lead-Free Solders

    Directory of Open Access Journals (Sweden)

    Gyenes A.

    2017-06-01

    Full Text Available According to the directives (RoHS and WEEE adopted by the European Union, lead has been banned from the manufacturing processes because of its health and environmental hazards. Therefore, the development of lead-free solders is one of the most important research areas of the electronic industry. This paper investigates multicomponent Sn-Ag-Cu based lead-free solders with different compositions. The properties of the six-component Innolot (SAC+BiSbNi and two low-Ag containing alloys were compared with the widespread used SAC307 solder. Microstructure investigations and X-ray diffraction measurements were performed to analyze and identify the formed phases, furthermore, tensile tests and microhardness measurements were executed to determine the mechanical properties of the examined solders.

  11. Optical anisotropy effects in lead tungstate crystals

    CERN Document Server

    Chipaux, Rémi

    1998-01-01

    The anisotropic crystal structure of lead tungstate leads to strong consequences in its optical properties and their characterization. Beyond the variation of surface reflections due to the birefringence of the material, we report the observation that part of the bulk light absorption is sensitive to the light polarization direction. This variable part varies with the quality of the crystal, and is clearly related to internal structural defects. Irradiation experiments with gamma rays or fast neutrons confirm the recent improvement of the short term resistance of this scintillator. Its long term behaviour remains identical, and acceptable for the use in high energy electromagnetic calorimetry. A polarization direction dependant induced absorption is observed, specially after high levels of radiation. Ray tracing programs in development for the simulation of the light yield in lead tungstate should take into account all these anisotropic effects.

  12. Materials aspects of implantable cardiac pacemaker leads.

    Science.gov (United States)

    Bruck, S D; Mueller, E P

    1988-01-01

    The reliability of the leads of the entire pacemaker system is vital as the risks of failure include: (1) loss of pacing due to the deterioration of the polymeric insulator in the physiological environment; (2) thromboembolism due to inadequate blood compatibility of the insulator; (3) tissue reactions at the electrode/tissue interface; (4) general foreign body rejection phenomena; (5) perforation of the leads; and (6) excessive stress applied by sutures causing abrasion and stress cracking. Although silicone has been used widely, some years ago Pellethane (a segmented polyetherurethane-urea) has been introduced as an alternate lead insulator, chiefly because it can be extruded using additives into smooth and thin tubes. The additives (antioxidants), extrusion aids, and low molecular weight polymer chains (oligomers) together represent up to approximately 8% by weight of leachables, depending on the extraction medium. The in vivo degradation of Pellethane is biologic in nature and is most likely associated with the absorption and premeation of body fluids from the surrounding physiologic environment leading to stress cracking via the formation of microvoids. Thermally and biologically unstable biuret and allophonate groups in this polyurethane, exposure of the polymer to high extrusion temperatures, and stresses created within the polymer also play key roles in the degradation process. In the case of electrodes, some corrosion can occur even with noble metals and ions formed with the involvement of penetrating body fluids which may combine with the urethane and/or urea groups of the polyurethane, leading to its further degradation in vivo. The totality of the situation indicates a need for the development of a standard guideline for the uniform and consistent pre-clinical testing and evaluation of new materials and fabrication processes of implantable pacemaker leads. Such guidelines should take into consideration, among others, the physiological environment

  13. Spray forming lead strip. Final report

    Energy Technology Data Exchange (ETDEWEB)

    McHugh, K.

    1996-04-10

    A cooperative research project was conducted between the Idaho National Engineering Laboratory (INEL) and Johnson Controls, Inc. (JCI) to adapt the INEL spray forming process to produce near-net-shape lead alloy strip. The emphasis of the work was to spray form lead strip samples at INEL, using a variety of spray conditions, for characterization at JCI. An existing glove box apparatus was modified at INEL to spray form lead. The main spray forming components were housed inside the glove box. They included a spray nozzle, tundish (crucible), substrate assembly, gas heater and furnaces to heat the nozzle and tundish. To spray form metal strip, liquid metal was pressure-fed at a controlled rate through a series of circular orifices that span the width of the nozzle. There the metal contacted high velocity, high temperature inert gas (nitrogen) which atomized the molten material into fine droplets, entrained the droplets in a directed flow, and deposited them onto glass plates that were swept through the spray plume to form strip samples. In-flight convection cooling of the droplets followed by conduction and convection cooling at the substrate resulted in rapid solidification of the deposit. During operation, the inside of the glove box was purged with an inert gas to limit the effects of in-flight oxidation of the particles and spray-formed strips, as well as to protect personnel from exposure to airborne lead particulate. Remote controls were used to start/stop the spray and control the speed and position of the substrate. In addition, substrate samples were loaded into the substrate translator manually using the gloved side ports of the box. In this way, the glove box remained closed during a series of spray trials, and was opened only when loading the crucible with a lead charge or when removing lead strip samples for shipment to JCI.

  14. The Number of Recalled Leads is Highly Predictive of Lead Failure: Results From the Pacemaker and Implantable Defibrillator Leads Survival Study ("PAIDLESS").

    Science.gov (United States)

    Kersten, Daniel J; Yi, Jinju; Feldman, Alyssa M; Brahmbhatt, Kunal; Asheld, Wilbur J; Germano, Joseph; Islam, Shahidul; Cohen, Todd J

    2016-12-01

    The purpose of this study was to determine if implantation of multiple recalled defibrillator leads is associated with an increased risk of lead failure. The authors of the Pacemaker and Implantable Defibrillator Leads Survival Study ("PAIDLESS") have previously reported a relationship between recalled lead status, lead failure, and patient mortality. This substudy analyzes the relationship in a smaller subset of patients who received more than one recalled lead. The specific effects of having one or more recalled leads have not been previously examined. This study analyzed lead failure and mortality of 3802 patients in PAIDLESS and compared outcomes with respect to the number of recalled leads received. PAIDLESS includes all patients at Winthrop University Hospital who underwent defibrillator lead implantation between February 1, 1996 and December 31, 2011. Patients with no recalled ICD leads, one recalled ICD lead, and two recalled ICD leads were compared using the Kaplan-Meier method and log-rank test. Sidak adjustment method was used to correct for multiple comparisons. All calculations were performed using SAS 9.4. P-values leads implanted during the trial period. There were 2400 leads (59%) in the no recalled leads category, 1620 leads (40%) in the one recalled lead category, and 58 leads (1%) in the two recalled leads category. No patient received more than two recalled leads. Of the leads categorized in the two recalled leads group, 12 experienced lead failures (21%), which was significantly higher (Pleads group (60 failures, 2.5%) and one recalled lead group (81 failures; 5%). Multivariable Cox's regression analysis found a total of six significant predictive variables for lead failure including the number of recalled leads (Pleads group). The number of recalled leads is highly predictive of lead failure. Lead-based multivariable Cox's regression analysis produced a total of six predictive variable categories for lead failure, one of which was the number

  15. Does Falling Smoking Lead to Rising Obesity?

    OpenAIRE

    Jonathan Gruber; Michael Frakes

    2005-01-01

    The strong negative correlation over time between smoking rates and obesity have led some to suggest that reduced smoking is increasing weight gain in the U.S.. This conclusion is supported by the findings of Chou et al. (2004), who conclude that higher cigarette prices lead to increased body weight. We investigate this issue and find no evidence that reduced smoking leads to weight gain. Using the cigarette tax rather than the cigarette price and controlling for non-linear time effects, we f...

  16. Lifetime modelling of lead acid batteries

    DEFF Research Database (Denmark)

    Bindner, H.; Cronin, T.; Lundsager, P.

    2005-01-01

    , therefore, lead to uncertainty in the viability of the system in the long term. This report details the work undertaken to investigate and develop two different battery life prediction methodologies withspecific reference to their use in hybrid renewable energy systems. Alongside this, results from battery...... been part of the European Union Benchmarking research project (ENK6-CT-2001-80576), funded by theEuropean Union, the United States and Australian governments together with other European states and other public and private financing bodies. The project has concentrated on lead acid batteries...

  17. Tool for Crimping Flexible Circuit Leads

    Science.gov (United States)

    Hulse, Aaron; Diftler, Myron A.

    2009-01-01

    A hand tool has been developed for crimping leads in flexible tails that are parts of some electronic circuits -- especially some sensor circuits. The tool is used to cut the tails to desired lengths and attach solder tabs to the leads. For tailoring small numbers of circuits for special applications, this hand tool is a less expensive alternative to a commercially available automated crimping tool. The crimping tool consists of an off-the-shelf hand crimping tool plus a specialized crimping insert designed specifically for the intended application.

  18. Lead Leached into Water from Select Plumbing Fixtures” Could Lead to Health Hazard

    Directory of Open Access Journals (Sweden)

    Ramsey Coles

    2014-01-01

    Full Text Available Background: Lead is an inert metal and is resistant to corrosion. It also increases tensile strength of many common materials in daily use. Lead was used during the Roman period to transport water (hence the name plumbing/plumber is common terminology even in the present day. Lead enters the biological system through the air, water, and dust. Fine particles of lead, having diameter less than 5 nm are directly absorbed by lungs. Inorganic lead is absorbed by the gastrointestinal tract, and organic lead is absorbed by the skin. Lead has long been known to be a toxic heavy metal and exposure is associated with many deleterious health effects. Still, lead remains a popular ingredient in products ranging from paint to batteries. The lead content in any given material is estimated using various methods. The least cumbersome method is found to be X-Ray Fluorescence technique (XRF. A portable XRF device was used in the present study. Aim: The main aim of this study to investigate whether lead is present in various commonly used plumbing materials. Material and Methods: All types of branded and commonly used pipes were gathered from a market in Bangalore and tested using the XRF machine. In order to evaluate to what extent lead from the pipes could leach into water, seven pipes were randomly selected and filled with Aquafina water (having undetectable level of lead for a 24 hour period. This water was tested at an NABL accredited laboratory in Bangalore, India for lead content. Result: It was determined that lead was present in many of the samples, at an unacceptable levels ranging from, well above the globally accepted level of 0.01 mg/L proof that lead was able to leach from the samples into water. Conclusions: As lead in drinking water represents a direct pathway for human exposure, the authors recommend that significant measures be taken to prevent use of lead in the plumbing industry for prevention of it’s deleterious effects. Authors have also

  19. Modeling of Blood Lead Levels in Astronauts Exposed to Lead from Microgravity-Accelerated Bone Loss

    Science.gov (United States)

    Garcia, H.; James, J.; Tsuji, J.

    2014-01-01

    Human exposure to lead has been associated with toxicity to multiple organ systems. Studies of various population groups with relatively low blood lead concentrations (bones, the adverse effects of lead correlate with the concentration of lead in the blood better than with that in the bones. NASA has found that prolonged exposure to microgravity during spaceflight results in a significant loss of bone minerals, the extent of which varies from individual to individual and from bone to bone, but generally averages about 0.5% per month. During such bone loss, lead that had been stored in bones would be released along with calcium. The effects on the concentration of lead in the blood (PbB) of various concentrations of lead in drinking water (PbW) and of lead released from bones due to accelerated osteoporosis in microgravity, as well as changes in exposure to environmental lead before, during, and after spaceflight were evaluated using a physiologically based pharmacokinetic (PBPK) model that incorporated exposure to environmental lead both on earth and in flight and included temporarily increased rates of osteoporosis during spaceflight.

  20. Pacemaker lead fracture without an increase in lead impedance caused by cardiac fibroma

    Directory of Open Access Journals (Sweden)

    Daisuke Sato

    2013-12-01

    Full Text Available We report the case of a 64-year-old man who had a permanent pacemaker with a unipolar silicone electrode positioned in the right ventricle in 1989 for sinus node dysfunction. On a routine checkup in June 2011, a 28-mm-diameter mass was discovered, which appeared to adhere to the tricuspid valve and the ventricular lead. The size of the mass did not change for the next 6 months, and the lead impedance was maintained at around 500–600 Ω. Because pacing failure was observed in January 2012, he underwent an urgent pacemaker check; however, the lead impedance was found not to have increased greatly (689 Ω. Nevertheless, the pacemaker lead was noted to be fractured at the tricuspid level. His echocardiogram showed new severe tricuspid regurgitation and a floating mass around the lead. We extracted the fractured lead, enucleated the tumor, replaced the tricuspid valve, and placed an epicardial lead. Macroscopic examination revealed that the tumor surrounded the fractured lead and covered the stump. Pathological examination revealed that the tumor was composed of fibrous connective tissue. We presumed that electric current continued to flow through the stump of the fractured unipolar lead to the generator, and this might have caused the limited increase in lead impedance.

  1. Lead level in seminal plasma may affect semen quality for men without occupational exposure to lead.

    Science.gov (United States)

    Wu, Hsien-Ming; Lin-Tan, Dan-Tzu; Wang, Mei-Li; Huang, Hong-Yuan; Lee, Chyi-Long; Wang, Hsin-Shih; Soong, Yung-Kuei; Lin, Ja-Liang

    2012-11-08

    Infertility affects approximately 10-15% of reproductive-age couples. Poor semen quality contributes to about 25% of infertile cases. Resulting from the direct effect on testicular function or hormonal alterations, heavy metals exposure has been related to impaired semen quality. The objective of this study was to assess the level of lead in the seminal plasma in men without occupational exposure to lead, and to determine the relationship between semen quality and lead concentration in the semen. This is a prospective and nonrandomized clinical study conducted in University infertility clinic and academic research laboratory. Three hundred and forty-one male partners of infertile couples undergoing infertility evaluation and management were recruited to the study. Semen samples collected for the analyses of semen quality were also used for the measurement of lead concentrations. Semen samples were evaluated according to the WHO standards. All subjects were married and from infertile couples without occupational exposure to lead. There is a significant inverse correlation between the lead concentration in seminal plasma and sperm count. A higher semen lead concentration was correlated with lower sperm count, but not with semen volume, sperm motility or sperm morphology as assessed by simple linear regression. We found that semen lead concentration was significantly higher among the patients with lower sperm count. To our knowledge, this is the first study to demonstrate that a high level of lead accumulation in semen may reduce the sperm count contributing to infertility of men without occupational exposure to lead.

  2. Lead sources to California sea otters: Industrial inputs circumvent natural lead biodepletion mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Smith, D.R.; Flegal, A.R. (Univ. of California, Santa Cruz (United States)); Niemeyer, S. (Lawrence Livermore National Lab., CA (United States))

    1992-04-01

    Lead levels (as Pb/Ca atom ratios) and stable isotopic compositions were measured in teeth of preindustrial and contemporary California sea otters (Enhydra lutris) to determine if postindustrial changes had occurred in the magnitude and source of accumulated lead. Lead/calcium atom ratios in teeth of some contemporary animals were significantly elevated and compared to level in other contemporary and preindustrial otters. The isotopic ratios revealed a change in the sources of accumulated leads, from natural continental-derived lead in the preindustrial animals ({sup 207}Pb/{sup 206}Pb = 0.820 {plus minus} 0.002) to industrial sources dominated by aerosol lead in the contemporary otters ({sup 207}Pb/{sup 206}Pb = 0.853), who contained lead derived from an industrial waste lead deposit in Monterey Harbor. These data establish distinguishable sources of lead assimilated by sea otters, and indicate that elevated exposures to some animals circumvented the natural biodepletion of lead through marine trophic pathways.

  3. Lead Contents and Distribution Characteristics of Soils and Vegetables Around an Abandoned Lead Smeltery

    Directory of Open Access Journals (Sweden)

    ZOU Tian-sen

    2016-07-01

    Full Text Available In order to disclose the degree and scope of lead pollution of the abandoned lead smeltery, 102 surface soil samples and 69 vegetables samples were collected by using the method of fan-shaped sampling points around an abandoned lead smeltery in Hubei Province. The lead contents of soils and vegetables were detected by graphite furnace atomic absorption spectrometry and inductively coupled plasma atomic emission spectrometry, respectively, and the lead spatial distribution was analyzed. The results showed that the geometric mean of lead contents in soils around the abandoned lead smeltery was 39.8 mg·kg-1 and exceeded the soil background value of Hubei Province(26.7 mg·kg-1. The mean value of geo-accumulation indexes of lead contents in soil was 0.09, and 36.4% of them exceeded zero. The geo-accumulation indexes of sampling distance of 500, 1000 m and 1500 m from the smeltery were 2.11, 0.61 and 0.33, respectively, while the values of sampling distances of more than 2000 m were all less than zero. 24.0%、36.0% and 6.3% of the lead contents exceeded the standard value of limited standards of contaminants in vagetables for cabbage, radish and green onion samples, respectively. The soils and vegetables around the abandonded lead smeltery within 500 m were contaminated seriously. The degree of lead pollution in soils was mild or moderate within 500 m to 2000 m, and the maximum scope in cabbage, radish and green onion was polluted within 500~1000, 1000~1500 m and 500~1000 m, respectively. Lead pollution in vegetables around the abandonded lead smeltery presented obvious characteristics of high pollution and enrichment.

  4. Failure of implantable cardioverter-defibrillator leads: a matter of lead size?

    Science.gov (United States)

    Rordorf, Roberto; Poggio, Luca; Savastano, Simone; Vicentini, Alessandro; Petracci, Barbara; Chieffo, Enrico; Klersy, Catherine; Landolina, Maurizio

    2013-02-01

    Small-diameter implantable cardioverter-defibrillator (ICD) Sprint Fidelis and Riata leads have been recalled owing to an increased risk of lead failure, thus arousing the suspicion that lead size might be a critical issue. To compare the incidence of failure of small-diameter (≤8 F) and standard-diameter (>8 F) ICD leads implanted in a single center. From January 2003 to December 2010, 190 Sprint Fidelis, 182 Riata/Riata ST, 99 Optim (Riata Optim/Durata), and 419 standard-diameter leads were implanted in our center. During a median follow-up of 33 months, the overall failure rate was 6.3%. Follow-up duration was similar for Sprint Fidelis, Riata, and standard-diameter leads but shorter for the Optim group. The failure rate was significantly higher in Sprint Fidelis leads than in both standard-diameter (4.8%/year vs 0.8%/year; Pleads. The incidence of lead failure in Riata/Riata ST leads proved significantly higher than in standard-diameter leads (2.6%/year vs 0.8%/year; P = .001). No cases of lead failure were recorded in the Optim group. On multivariable analyses, small-diameter (hazard ratio [HR] 5.03, 2.53-10.01, Pleads and agelead failure. Compared with standard-diameter leads, both Sprint Fidelis and Riata/Riata ST small-diameter ICD leads are at an increased risk of failure, although the incidence of events is significantly lower in the Riata than in the Sprint Fidelis group. Copyright © 2013 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  5. Soil is an important pathway of human lead exposure.

    OpenAIRE

    Mielke, H W; Reagan, P L

    1998-01-01

    This review shows the equal or greater importance of leaded gasoline-contaminated dust compared to lead-based paint to the child lead problem, and that soil lead, resulting from leaded gasoline and pulverized lead-based paint, is at least or more important than lead-based paint (intact and not pulverized) as a pathway of human lead exposure. Because lead-based paint is a high-dose source, the biologically relevant dosage is similar to lead in soil. Both lead-based paint and soil lead are asso...

  6. Can climate change lead to gap formation ?

    NARCIS (Netherlands)

    Berestycki, Henri; Desvillettes, Laurent; Diekmann, Odo

    2014-01-01

    Consider a situation where spatial heterogeneity leads to a cline, a gradual transition in dominance of two competing species. We first prove, in the context of a simplified competition–diffusion model, that there exists a stationary solution showing that the two species coexist in a transition

  7. Lead Paint Test Kits Workshop: Summary Report

    Science.gov (United States)

    The U.S. Environmental Protection Agency's (EPA) Office of Research and Development (ORD) designed and conducted the Lead Paint Test Kits Workshop on October 19 and 20, 2006, at the Environmental Protection Agency's Research Triangle Park, NC campus. The workshop was conducted as...

  8. Maritime Load Dependent Lead Times - An Analysis

    DEFF Research Database (Denmark)

    Pahl, Julia; Voss, Stefan

    2017-01-01

    Traditionally, the maritime sector follows a very conservative approach towards sharing information and adopting information technology (IT) to stream-line logistic activities. Late arrivals of ships create problems especially with the trend to build large ships leading to peak loads of process...

  9. Industrial Dynamics Beyond the Lead Firms

    DEFF Research Database (Denmark)

    Haakonsson, Stine Jessen; Slepniov, Dmitrij

    2013-01-01

    Since the turn of the millennium, China has developed into a core location for the wind energy industry and is today the largest market for wind turbines. These developments have caught attention among scholars. However, most research is on the development of the market and the lead firm strategi...

  10. CHILDHOOD RISK ESTIMATION OF LEAD METAL POISOINING ...

    African Journals Online (AJOL)

    Dr Osondu

    2011-10-28

    Oct 28, 2011 ... The childhood lead (Pb) poisoning risk from consumption and risk model data of snail meat from Pb metal contaminated sites of entrance (control), storage dump, dried effluent and waste dump at an abandoned battery factory, in Niger Delta, Nigeria were estimated. Results implicated snail meat from.

  11. Proton beam modification of lead white pigments

    Energy Technology Data Exchange (ETDEWEB)

    Beck, L., E-mail: lucile.beck@cea.fr [CEA, DEN, Service de Recherches de Métallurgie Physique, Laboratoire JANNUS, 91191 Gif-sur-Yvette (France); Centre de recherche et de restauration des musées de France (C2RMF), Palais du Louvre – Porte des Lions, 14 quai François Mitterrand, 75001 Paris (France); Gutiérrez, P.C. [Centre de recherche et de restauration des musées de France (C2RMF), Palais du Louvre – Porte des Lions, 14 quai François Mitterrand, 75001 Paris (France); Centro de Micro-Análisis de Materiales (CMAM), Universidad Autónoma de Madrid, Campus de Cantoblanco, E-28049 Madrid (Spain); Miserque, F. [CEA, DEN, DPC/SCCME/LECA, 91191 Gif-sur-Yvette (France); Thomé, L. [Centre de Spectrométrie Nucléaire et de Spectrométrie de Masse (CSNSM), CNRS/IN2P3 et Université Paris-Sud, Bât. 108, 91405 Orsay (France)

    2013-07-15

    Pigments and paint materials are known to be sensitive to particle irradiation. Occasionally, the analysis of paintings by PIXE can induce a slight or dark stain depending on the experimental conditions (beam current, dose, particle energy). In order to understand this discoloration, we have irradiated various types of art white pigments – lead white (hydrocerussite and basic lead sulfate), gypsum, calcite, zinc oxide and titanium oxide – with an external 3 MeV proton micro-beam commonly used for PIXE experiments. We have observed various sensitivities depending on the pigment. No visible change occurs for calcite and titanium oxide, whereas lead white pigments are very sensitive. For the majority of the studied compounds, the discoloration is proportional to the beam current and charge. The damage induced by proton beam irradiation in lead white pigments was studied by micro-Raman and XPS spectroscopies. Structural modifications and dehydration were detected. Damage recovery was investigated by thermal treatment and UV-light irradiation. The discoloration disappeared after one week of UV illumination, showing that PIXE experiments could be safely undertaken for pigments and paintings.

  12. Leading in a Culture of Change.

    Science.gov (United States)

    Fullan, Michael

    The more complex society gets, the more sophisticated leadership must become. This book is about how leaders can focus on certain key change themes that will allow them to lead effectively under messy conditions. Chapter 1 identifies theoretical reasons why change occurs as it does. They include moral purpose, understanding change, developing…

  13. Improving Order Lead Time: A Case Study

    Science.gov (United States)

    Villarreal, Bernardo; Salido, Lucy

    2009-01-01

    A fundamental challenge of globally competing companies is to increase their level of customer satisfaction, by devising and implementing strategies aimed at providing better price, quality, and service. This paper describes the efforts of a Mexican company to achieve this goal, and in particular, with the need to decrease order lead time…

  14. Acute hyperventilation leading to hypocalcaemia during spinal ...

    African Journals Online (AJOL)

    Adele

    semi open systems (Mapleson A to F) with appropriate flow or circle with absorber excluded and a low flow of gases would have achieved it.8 The resulting decrease in pH leads to a normalization of ionized calcium level. However, we were not able to use it because of the difficulty encountered in providing a tight mask ...

  15. Does Education Lead to Higher Generalized Trust?

    DEFF Research Database (Denmark)

    Charron, Nicholas; Rothstein, Bo

    2016-01-01

    to ‘trust others'. We hypothesize that higher levels of education will lead to higher social trust in individuals, given that the context (country or regions within countries) in which they reside has a sufficiently impartial and non-corrupt institutional setting. However, the positive effect of education...

  16. When municipalities lead co-production

    DEFF Research Database (Denmark)

    Tortzen, Anne

    2015-01-01

    This article explores the role played by municipalities as ‘key leaders’ in co-production processes initiated by local governments. The aim is to produce new insights into the challenges faced by public agencies leading co-production processes in practice. Drawing on an analytical framework derived...

  17. Do Policy Networks lead to Network Governing?

    DEFF Research Database (Denmark)

    Damgaard, Bodil

    This paper challenges the notion that creation of local policy networks necessarily leads to network governing. Through actor-centred case studies in the area of municipally implemented employment policy in Denmark it was found that the local governing mode is determined mainly by the municipality...

  18. Selected Bibliography on Lead Poisoning in Children.

    Science.gov (United States)

    Lin-Fu, Jane S., Comp.

    This comprehensive bibliography was prepared in response to the growing interest in the problem of childhood lead poisoning. Most of the papers noted are from the pediatric literature and include only those published in English. A limited number of papers on experiments in laboratory animals are cited. Documents are grouped under several general…

  19. Child Care Lead Poisoning Prevention. Training Curriculum.

    Science.gov (United States)

    California Dept. of Health Services, Oakland. Childhood Lead Poisoning Prevention Branch.

    In an effort to address young children's substantial risk for exposure to lead in out-of-home child care programs, outreach and training were developed for child care providers. This workshop curriculum consists of training activities and materials appropriate for child care providers in centers or homes for the purpose of educating them about the…

  20. Childhood Lead Poisoning: Resources for Prevention.

    Science.gov (United States)

    Alliance to End Childhood Lead Poisoning, Washington, DC.

    The current approach to dealing with childhood lead poisoning has led to repeated diagnoses of poisoning because such children are treated and then returned to their hazardous environments. This handbook, the third in a three-volume set, provides examples of specific materials currently or recently used in ongoing state and local childhood lead…