WorldWideScience

Sample records for bromine iodides

  1. Bromine

    Science.gov (United States)

    Ober, J.A.

    2013-01-01

    The element bromine is found principally as a dissolved species in seawater, evaporitic (salt) lakes and underground brines associated with petroleum deposits. Seawater contains about 65 parts per million of bromine or an estimated 907 Gt (100 trillion st). In the Middle East, the highly saline waters of the Dead Sea are estimated to contain 907 Mt (1 billion st) of bromine. Bromine also may be recovered from seawater as a coproduct during evaporation to produce salt.

  2. Potassium Iodide

    Science.gov (United States)

    Potassium iodide is used to protect the thyroid gland from taking in radioactive iodine that may be ... damage the thyroid gland. You should only take potassium iodide if there is a nuclear radiation emergency ...

  3. Bromine Safety

    Energy Technology Data Exchange (ETDEWEB)

    Meyers, B

    2001-04-09

    The production and handling in 1999 of about 200 million kilograms of bromine plus substantial derivatives thereof by Great Lakes Chemical Corp. and Albemarle Corporation in their southern Arkansas refineries gave OSHA Occupational Injury/Illness Rates (OIIR) in the range of 0.74 to 1.60 reportable OIIRs per 200,000 man hours. OIIRs for similar industries and a wide selection of other U.S. industries range from 1.6 to 23.9 in the most recent OSHA report. Occupational fatalities for the two companies in 1999 were zero compared to a range in the U.S.of zero for all computer manufacturing to 0.0445 percent for all of agriculture, forestry and fishing in the most recent OSHA report. These results show that bromine and its compounds can be considered as safe chemicals as a result of the bromine safety standards and practices at the two companies. The use of hydrobromic acid as an electrical energy storage medium in reversible PEM fuel cells is discussed. A study in 1979 of 20 megawatt halogen working fluid power plants by Oronzio de Nora Group found such energy to cost 2 to 2.5 times the prevailing base rate at that time. New conditions may reduce this relative cost. The energy storage aspect allows energy delivery at maximum demand times where the energy commands premium rates. The study also found marginal cost and performance advantages for hydrobromic acid over hydrochloric acid working fluid. Separate studies in the late 70s by General Electric also showed marginal performance advantages for hydrobromic acid.

  4. Bromination of Phenol

    Science.gov (United States)

    Talbot, Christopher

    2013-01-01

    This "Science note" examines the bromination of phenol, a reaction that is commonly taught at A-level and IB (International Baccalaureate) as an example of electrophilic substitution. Phenol undergoes bromination with bromine or bromine water at room temperature. A white precipitate of 2,4,6-tribromophenol is rapidly formed. This…

  5. Synthesis of mercuric iodide and bismuth tri-iodide nanoparticles for heavy metal iodide films nucleation

    Energy Technology Data Exchange (ETDEWEB)

    Fornaro, L.; Pereira, H.Bentos [Compound Semiconductors Group, CURE, Universidad de la Republica, Rocha (Uruguay); Aguiar, I.; Perez Barthaburu, M. [Compound Semiconductors Group, Facultad de Quimica, Univ. de la Republica, Montevideo (Uruguay)

    2011-12-15

    We synthesized mercuric iodide and bismuth tri-iodide nanoparticles by suspension in octadecene, from Hg(NO{sub 3}){sub 2}.H{sub 2}O and I{sub 2}, and from Bi(NO{sub 3}){sub 3}.5H{sub 2}O and I{sub 2}, respectively. The best synthesis conditions were 2 h at 70-80 C, followed by 10 min at 110 C for mercuric iodide nanoparticles, and 4 h at 80-110 C, followed by 10 min at 180-210 C for bismuth tri-iodide ones. Nanoparticles were then washed and centrifuged with ether repeatedly. Compounds identity was confirmed by X-ray diffraction (XRD) and energy dispersive spectrometry (EDS). We found shifts of the X-ray diffraction maxima for nanoparticles of both compounds. We characterized the nanoparticles by transmission (TEM) and scanning (SEM) electron microscopy. We obtained disk-like and squared mercuric iodide nanostructures, 80-140 nm and 100-125 nm in size respectively. We also obtained rounded and rod-like bismuth tri-iodide nanoparticles, 30-500 nm in size. Acetonitrile and isopropanol suspensions of mercuric iodide nanoparticles, and acetonitrile suspension of bismuth tri-iodide nanoparticles exhibited peak maxima shifts in their UV-Vis spectra. We synthesized for the first time mercuric iodide and bismuth tri-iodide nanoparticles by the suspension method, although we have not yet obtained uniform shape and size distributions. They offer interesting perspectives for crystalline film nucleation and for improving current applications of these materials, as well as for opening new ones. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  6. 21 CFR 172.375 - Potassium iodide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium iodide. 172.375 Section 172.375 Food and... Dietary and Nutritional Additives § 172.375 Potassium iodide. The food additive potassium iodide may be safely used in accordance with the following prescribed conditions: (a) Potassium iodide may be...

  7. Mercuric iodide sensor technology

    International Nuclear Information System (INIS)

    This report describes the improvement in the performance and the manufacturing yield of mercuric iodide detectors achieved by identifying the dominant impurities, carrier traps, and processing steps limiting device performance. Theoretical studies of electron and hole transport in this material set fundamental limits on detector performance and provided a standard against which to compare experimental results. Spectroscopy techniques including low temperature photoluminescence and thermally stimulated current spectroscopy were applied to characterize the deep level traps in this material. Traps and defects that can be introduced into the detector during growth, from the contact, and during the various steps in detector fabrication were identified. Trap energy levels and their relative abundances were determined. Variations in material quality and detector performance at the micron scale were investigated to understand the distribution in electric field in large volume detectors suitable for gamma-ray spectroscopy. Surface aging and contact degradation was studied extensively by techniques including atomic force microscopy, transmission electron microscopy, and variable angle spectroscopic ellipsometry. Preferred handling and processing procedures for maximizing detector performance and yield were established. The manufacturing yield of high resolution gamma-ray detectors was improved from a few percent to more than 30%

  8. Toxic impact of bromide and iodide on drinking water disinfected with chlorine or chloramines.

    Science.gov (United States)

    Yang, Yang; Komaki, Yukako; Kimura, Susana Y; Hu, Hong-Ying; Wagner, Elizabeth D; Mariñas, Benito J; Plewa, Michael J

    2014-10-21

    Disinfectants inactivate pathogens in source water; however, they also react with organic matter and bromide/iodide to form disinfection byproducts (DBPs). Although only a few DBP classes have been systematically analyzed for toxicity, iodinated and brominated DBPs tend to be the most toxic. The objectives of this research were (1) to determine if monochloramine (NH2Cl) disinfection generated drinking water with less toxicity than water disinfected with free chlorine (HOCl) and (2) to determine the impact of added bromide and iodide in conjunction with HOCl or NH2Cl disinfection on mammalian cell cytotoxicity and genomic DNA damage induction. Water disinfected with chlorine was less cytotoxic but more genotoxic than water disinfected with chloramine. For both disinfectants, the addition of Br(-) and I(-) increased cytotoxicity and genotoxicity with a greater response observed with NH2Cl disinfection. Both cytotoxicity and genotoxicity were highly correlated with TOBr and TOI. However, toxicity was weakly and inversely correlated with TOCl. Thus, the forcing agents for cytotoxicity and genotoxicity were the generation of brominated and iodinated DBPs rather than the formation of chlorinated DBPs. Disinfection practices need careful consideration especially when using source waters containing elevated bromide and iodide.

  9. 21 CFR 184.1634 - Potassium iodide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Potassium iodide. 184.1634 Section 184.1634 Food... Specific Substances Affirmed as GRAS § 184.1634 Potassium iodide. (a) Potassium iodide (KI, CAS Reg. No. 7681-11-0) is the potassium salt of hydriodic acid. It occurs naturally in sea water and in...

  10. 21 CFR 582.5634 - Potassium iodide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Potassium iodide. 582.5634 Section 582.5634 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Supplements 1 § 582.5634 Potassium iodide. (a) Product. Potassium iodide. (b) Tolerance. 0.01 percent....

  11. Interactions of bromine, chlorine, and iodine photochemistry during ozone depletions in Barrow, Alaska

    Directory of Open Access Journals (Sweden)

    C. R. Thompson

    2014-11-01

    Full Text Available The springtime depletion of tropospheric ozone in the Arctic is known to be caused by active halogen photochemistry resulting from halogen atom precursors emitted from snow, ice, or aerosol surfaces. The role of bromine in driving ozone depletion events (ODEs has been generally accepted, but much less is known about the role of chlorine radicals in ozone depletion chemistry. While the potential impact of iodine in the High Arctic is more uncertain, there have been indications of active iodine chemistry through observed enhancements in filterable iodide, probable detection of tropospheric IO, and recently, detection of atmospheric I2. Despite decades of research, significant uncertainty remains regarding the chemical mechanisms associated with the bromine-catalyzed depletion of ozone, as well as the complex interactions that occur in the polar boundary layer due to halogen chemistry. To investigate this, we developed a zero-dimensional photochemical model, constrained with measurements from the 2009 OASIS field campaign in Barrow, Alaska. We simulated a 7 day period during late March that included a full ozone depletion event lasting 3 days and subsequent ozone recovery to study the interactions of halogen radicals under these different conditions. In addition, the effects of iodine added to our base model were investigated. While bromine atoms were primarily responsible for ODEs, chlorine and iodine were found to enhance the depletion rates and iodine was found to be more efficient per atom at depleting ozone than Br. The interaction between chlorine and bromine is complex, as the presence of chlorine can increase the recycling and production of Br atoms, while also increasing reactive bromine sinks under certain conditions. Chlorine chemistry was also found to have significant impacts on both HO2 and RO2. The results of this work highlight the need for future studies on the production mechanisms of Br2 and Cl2, as well as on the potential

  12. Interactions of bromine, chlorine, and iodine photochemistry during ozone depletions in Barrow, Alaska

    Science.gov (United States)

    Thompson, C. R.; Shepson, P. B.; Liao, J.; Huey, L. G.; Apel, E. C.; Cantrell, C. A.; Flocke, F.; Orlando, J.; Fried, A.; Hall, S. R.; Hornbrook, R. S.; Knapp, D. J.; Mauldin, R. L., III; Montzka, D. D.; Sive, B. C.; Ullmann, K.; Weibring, P.; Weinheimer, A.

    2015-08-01

    The springtime depletion of tropospheric ozone in the Arctic is known to be caused by active halogen photochemistry resulting from halogen atom precursors emitted from snow, ice, or aerosol surfaces. The role of bromine in driving ozone depletion events (ODEs) has been generally accepted, but much less is known about the role of chlorine radicals in ozone depletion chemistry. While the potential impact of iodine in the High Arctic is more uncertain, there have been indications of active iodine chemistry through observed enhancements in filterable iodide, probable detection of tropospheric IO, and recently, observation of snowpack photochemical production of I2. Despite decades of research, significant uncertainty remains regarding the chemical mechanisms associated with the bromine-catalyzed depletion of ozone, as well as the complex interactions that occur in the polar boundary layer due to halogen chemistry. To investigate this, we developed a zero-dimensional photochemical model, constrained with measurements from the 2009 OASIS field campaign in Barrow, Alaska. We simulated a 7-day period during late March that included a full ozone depletion event lasting 3 days and subsequent ozone recovery to study the interactions of halogen radicals under these different conditions. In addition, the effects of iodine added to our Base Model were investigated. While bromine atoms were primarily responsible for ODEs, chlorine and iodine were found to enhance the depletion rates and iodine was found to be more efficient per atom at depleting ozone than Br. The interaction between chlorine and bromine is complex, as the presence of chlorine can increase the recycling and production of Br atoms, while also increasing reactive bromine sinks under certain conditions. Chlorine chemistry was also found to have significant impacts on both HO2 and RO2, with organic compounds serving as the primary reaction partner for Cl atoms. The results of this work highlight the need for future

  13. Iodine and bromine speciation in snow and the effect of orographically induced precipitation

    Directory of Open Access Journals (Sweden)

    H. Biester

    2007-05-01

    Full Text Available Iodine is an essential trace element for all mammals and may also influence climate through new aerosol formation. Atmospheric bromine cycling is also important due to its well-known ozone depletion capabilities. Despite precipitation being the ultimate source of iodine in the terrestrial environment, the processes effecting its distribution, speciation and transport are relatively unknown. The aim of this study was to determine the effect of orographically induced precipitation on iodine concentrations in snow and also to quantify the inorganic and organic iodine and bromine species. Snow samples were collected over an altitude profile (~840 m from the northern Black Forest and were analysed by ion-chromatography - inductively coupled plasma mass spectrometry (IC-ICP-MS for iodine and bromine species and trace metals (ICP-MS. All elements and species concentrations in snow showed significant (r2>0.65 exponential decrease relationships with altitude despite the short (5 km horizontal distance of the transect. In fact, total iodine more than halved (38 to 13 nmol/l over the 840 m height change. The results suggest that orographic lifting and subsequent precipitation has a major influence on iodine concentrations in snow. This orographically induced removal effect may be more important than lateral distance from the ocean in determining iodine concentrations in terrestrial precipitation. The microphysical removal process was common to all elements indicating that the iodine and bromine are internally mixed within the snow crystals. We also show that organically bound iodine is the dominant iodine species in snow (61–75%, followed by iodide. Iodate was only found in two samples despite a detection limit of 0.3 nmol/l. Two unknown but most likely anionic organo-I species were also identified in IC-ICP-MS chromatograms and comprised 2–10% of the total iodine. The majority of the bromine was inorganic bromide with a max. of 32% organo-Br.

  14. Speciation of the bio-available iodine and bromine forms in edible seaweed by high performance liquid chromatography hyphenated with inductively coupled plasma-mass spectrometry

    International Nuclear Information System (INIS)

    Highlights: ► Bioavailable iodine and bromine speciation in edible seaweed were developed. ► In vitro dialyzability was used to assess the bioavailable fractions. ► AEC hyphenated with inductively coupled plasma-mass spectrometry was used. ► Iodide, MIT, DIT, bromide and bromate were found in dialyzates from edible seaweed. ► Positive correlation between bioavailability and protein contents was found. - Abstract: A bioavailability study based on an in vitro dialyzability approach has been applied to assess the bio-available fractions of iodine and bromine species from edible seaweed. Iodide, iodate, 3-iodo-tyrosine (MIT), 3,5-diiodo-tyrosine (DIT), bromide and bromate were separated by anion exchange chromatography under a gradient elution mode (175 mM ammonium nitrate plus 15% (v/v) methanol, pH 3.8, as a mobile phase, and flow rates within the 0.5–1.5 mL min−1 range). Inductively coupled plasma-mass spectrometry (ICP-MS) was used as a selective detector for iodine (127I) and bromine (79Br). Low dialyzability ratios (within the 2.0–18% range) were found for iodine species; whereas, moderate dialyzability percentages (from 9.0 to 40%) were obtained for bromine species. Iodide and bromide were the major species found in the dialyzates from seaweed, although MIT and bromate were also found in the dialyzates from most of the seaweed samples analysed. However, DIT was only found in dialyzates from Wakame, Kombu, and NIES 09 (Sargasso) certified reference material; whereas, iodate was not found in any dialyzate. Iodine dialyzability was found to be dependent on the protein content (negative correlation), and on the carbohydrate and dietary fibre levels (positive correlation). However, bromine dialyzability was only dependent on the protein amount in seaweed (negative correlation).

  15. Uptake of iodide in the marine haptophyte Isochrysis sp. (T.ISO) driven by iodide oxidation.

    Science.gov (United States)

    van Bergeijk, Stef A; Hernández Javier, Laura; Heyland, Andreas; Manchado, Manuel; Pedro Cañavate, José

    2013-08-01

    Uptake of iodide was studied in the marine microalga Isochrysis sp. (isol. Haines, T.ISO) during short-term incubations with radioactive iodide ((125) I(-) ). Typical inhibitors of the sodium/iodide symporter (NIS) did not inhibit iodide uptake, suggesting that iodide is not taken up through this transport protein, as is the case in most vertebrate animals. Oxidation of iodide was found to be an essential step for its uptake by T.ISO and it seemed likely that hypoiodous acid (HOI) was the form of iodine taken up. Uptake of iodide was inhibited by the addition of thiourea and of other reducing agents, like L-ascorbic acid, L-glutathione and L-cysteine and increased after the addition of oxidized forms of the transition metals Fe and Mn. The simultaneous addition of both hydrogen peroxide (H2 O2 ) and a known iodide-oxidizing myeloperoxidase (MPO) significantly increased iodine uptake, but the addition of H2 O2 or MPO separately, had no effect on uptake. This confirms the observation that iodide is oxidized prior to uptake, but it puts into doubt the involvement of H2 O2 excretion and membrane-bound or extracellular haloperoxidase activity of T.ISO. The increase of iodide uptake by T.ISO upon Fe(III) addition suggests the nonenzymatic oxidation of iodide by Fe(III) in a redox reaction and subsequent influx of HOI. This is the first report on the mechanism of iodide uptake in a marine microalga.

  16. Neutron Detection with Mercuric Iodide

    CERN Document Server

    Bell, Z A

    2003-01-01

    Mercuric iodide is a high-density, high-Z semiconducting material useful for gamma ray detection. This makes it convertible to a thermal neutron detector by covering it with a boron rich material and detecting the 478 keV gamma rays resulting from the sup 1 sup 0 B(n, alpha) sup 7 Li* reaction. However, the 374 barn thermal capture cross section of sup n sup a sup t Hg, makes the detector itself an attractive absorber, and this has been exploited previously. Since previous work indicates that there are no low-energy gamma rays emitted in coincidence with the 368 keV capture gamma from the dominant sup 1 sup 9 sup 9 Hg(n, gamma) sup 2 sup 0 sup 0 Hg reaction, only the 368 keV capture gamma is seen with any efficiency a relatively thin (few mm) detector. In this paper we report preliminary measurements of neutrons via capture reactions in a bare mercuric iodide crystal and a crystal covered in sup 1 sup 0 B-loaded epoxy. The covered detector is an improvement over the bare detector because the presence of both ...

  17. Neutron Detection with Mercuric Iodide

    Energy Technology Data Exchange (ETDEWEB)

    Bell, Z.A.

    2003-06-17

    Mercuric iodide is a high-density, high-Z semiconducting material useful for gamma ray detection. This makes it convertible to a thermal neutron detector by covering it with a boron rich material and detecting the 478 keV gamma rays resulting from the {sup 10}B(n, {alpha}){sup 7}Li* reaction. However, the 374 barn thermal capture cross section of {sup nat}Hg, makes the detector itself an attractive absorber, and this has been exploited previously. Since previous work indicates that there are no low-energy gamma rays emitted in coincidence with the 368 keV capture gamma from the dominant {sup 199}Hg(n, {gamma}){sup 200}Hg reaction, only the 368 keV capture gamma is seen with any efficiency a relatively thin (few mm) detector. In this paper we report preliminary measurements of neutrons via capture reactions in a bare mercuric iodide crystal and a crystal covered in {sup 10}B-loaded epoxy. The covered detector is an improvement over the bare detector because the presence of both the 478 and 368 keV gamma rays removes the ambiguity associated with the observation of only one of them. Pulse height spectra, obtained with and without lead and cadmium absorbers, showed the expected gamma rays and demonstrated that they were caused by neutrons.

  18. Rare, severe hypersensitivity reaction to potassium iodide

    DEFF Research Database (Denmark)

    Nielsen, Anne Sofie Korsholm; Ebbehøj, Eva; Richelsen, Bjørn

    2014-01-01

    The literature reports a large variety of adverse reactions to potassium iodide. A severe hypersensitivity reaction to potassium iodide in a 51-year-old woman with Graves' thyrotoxicosis is described. Following administration the patient developed sialadenitis, conjunctivitis, stomatitis and acne...

  19. Two new brominated diterpenes from Laurencia decumbens

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Two new brominated diterpenes, namely, laurendecumtriol and 11-deacetylpinnaterpene C, were isolated and identified from the marine red alga Laurencia decumbens. Their structures were established on the basis of various NMR spectroscopic techniques and HR-ESI-MS analyses.

  20. Stability and metastability of bromine clathrate polymorphs.

    Science.gov (United States)

    Nguyen, Andrew H; Molinero, Valeria

    2013-05-23

    Clathrate hydrates are crystals in which water forms a network of fully hydrogen-bonded polyhedral cages that contain small guests. Clathrate hydrates occur mostly in two cubic crystal polymorphs, sI and sII. Bromine is one of two guests that yield a hydrate with the tetragonal structure (TS), the topological dual of the Frank-Kasper σ phase. There has been a long-standing disagreement on whether bromine hydrate also forms metastable sI and sII crystals. To date there are no data on the thermodynamic range of stability (e.g., the melting temperatures) of the metastable polymorphs. Here we use molecular dynamics simulations with the coarse-grained model of water mW to (i) investigate the thermodynamic stability of the empty and guest-filled the sI, sII, TS, and HS-I hydrate polymorphs, (ii) develop a coarse-grained model of bromine compatible with mW water, and (iii) evaluate the stability of the bromine hydrate polymorphs. The mW model predicts the same relative energy of the empty clathrate polymorphs and the same phase diagram as a function of water-guest interaction than the fully atomistic TIP4P water model. There is a narrow region in water-guest parameter space for which TS is marginally more stable than sI or sII. We parametrize a coarse-grained model of bromine compatible with mW water and use it to determine the order of stability of the bromine hydrate polymorphs. The melting temperatures of the bromine hydrate polymorphs predicted by the coarse-grained model are 281 ± 1 K for TS, 279 ± 1 K for sII, and 276 ± 1 K for sI. The closeness of the melting temperatures supports the plausibility of formation of metastable sII and sI bromine hydrates.

  1. Iodine and Bromine speciation in snow and the effect of elevation

    Directory of Open Access Journals (Sweden)

    B. S. Gilfedder

    2007-01-01

    Full Text Available Iodine is an essential trace element for all mammals and may also influence climate through new aerosol formation. Atmospheric bromine cycling is also important due to its well-known ozone depletion capabilities. Despite precipitation being the ultimate source of iodine in the terrestrial environment, the processes effecting the distribution, speciation and transport of these elements are relatively unknown. The aim of this study was to determine the effect of orographic lifting on iodine concentrations and also quantify inorganic and organic iodine and bromine species. Snow samples were collected over an altitude profile (~800 m from the northern Black Forest and were analysed (IC-ICP-MS for iodine and bromine species and trace metals (ICP-MS. All elements and species showed a significant (r2>0.65 inverse relationship with altitude despite the short (5 km horizontal distance of the transect. In fact, total iodine more than halved (38 to 13 nmol/l over the 800 m height change. The results suggest that orographic lifting of cloud masses has a major influence on iodine levels in precipitation and is perhaps more important than lateral distances in determining iodine concentrations in terrestrial precipitation. The microphysical removal process was common to all elements. We also show that organically bound iodine is the dominant iodine species in snow (61–75%, followed by iodide. Iodate was only found in two samples despite a detection limit of 0.3 nmol/l. Two unknown but most likely anionic organo-I species were also identified in IC-ICP-MS chromatograms and comprised 2–10% of the total iodine. The majority of the bromine was inorganic bromide with a max.~of 32% organo-Br.

  2. Predissociation dynamics of lithium iodide

    CERN Document Server

    Schmidt, H; Stienkemeier, F; Bogomolov, A S; Baklanov, A V; Reich, D M; Skomorowski, W; Koch, C P; Mudrich, M

    2015-01-01

    The predissociation dynamics of lithium iodide (LiI) in the first excited A-state is investigated for molecules in the gas phase and embedded in helium nanodroplets, using femtosecond pump-probe photoionization spectroscopy. In the gas phase, the transient Li+ and LiI+ ion signals feature damped oscillations due to the excitation and decay of a vibrational wave packet. Based on high-level ab initio calculations of the electronic structure of LiI and simulations of the wave packet dynamics, the exponential signal decay is found to result from predissociation predominantly at the lowest avoided X-A potential curve crossing, for which we infer a coupling constant V=650(20) reciprocal cm. The lack of a pump-probe delay dependence for the case of LiI embedded in helium nanodroplets indicates fast droplet-induced relaxation of the vibrational excitation.

  3. Predissociation dynamics of lithium iodide

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, H.; Vangerow, J. von; Stienkemeier, F.; Mudrich, M., E-mail: mudrich@physik.uni-freiburg.de [Physikalisches Institut, Universität Freiburg, 79104 Freiburg (Germany); Bogomolov, A. S. [Institute of Chemical Kinetics and Combustion, Novosibirsk 630090 (Russian Federation); Baklanov, A. V. [Institute of Chemical Kinetics and Combustion, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Reich, D. M.; Skomorowski, W.; Koch, C. P. [Theoretische Physik, Universität Kassel, Heinrich-Plett-Str. 40, 34132 Kassel (Germany)

    2015-01-28

    The predissociation dynamics of lithium iodide (LiI) in the first excited A-state is investigated for molecules in the gas phase and embedded in helium nanodroplets, using femtosecond pump-probe photoionization spectroscopy. In the gas phase, the transient Li{sup +} and LiI{sup +} ion signals feature damped oscillations due to the excitation and decay of a vibrational wave packet. Based on high-level ab initio calculations of the electronic structure of LiI and simulations of the wave packet dynamics, the exponential signal decay is found to result from predissociation predominantly at the lowest avoided X-A potential curve crossing, for which we infer a coupling constant V{sub XA} = 650(20) cm{sup −1}. The lack of a pump-probe delay dependence for the case of LiI embedded in helium nanodroplets indicates fast droplet-induced relaxation of the vibrational excitation.

  4. A, a Brominated Flame Retardant

    Directory of Open Access Journals (Sweden)

    Tomomi Takeshita

    2013-01-01

    Full Text Available Tetrabromobisphenol A (TBBPA, a brominated flame retardant, has been found to exacerbate pneumonia in respiratory syncytial virus- (RSV- infected mice. We examined the effect of Brazilian propolis (AF-08 on the exacerbation of RSV infection by TBBPA exposure in mice. Mice were fed a powdered diet mixed with 1% TBBPA alone, 0.02% AF-08 alone, or 1% TBBPA and 0.02% AF-08 for four weeks and then intranasally infected with RSV. TBBPA exposure increased the pulmonary virus titer and level of IFN-γ, a representative marker of pneumonia due to RSV infection, in the lungs of infected mice without toxicity. AF-08 was significantly effective in reducing the virus titers and IFN-γ level increased by TBBPA exposure. Also, AF-08 significantly reduced proinflammatory cytokine (TNF-α and IL-6 levels in the lungs of RSV-infected mice with TBBPA exposure, but Th2 cytokine (IL-4 and IL-10 levels were not evidently increased. Neither TBBPA exposure nor AF-08 treatment affected the anti-RSV antibody production in RSV-infected mice. In flow cytometry analysis, AF-08 seemed to be effective in reducing the ratio of pulmonary CD8a+ cells in RSV-infected mice with TBBPA exposure. TBBPA and AF-08 did not exhibit anti-RSV activity in vitro. Thus, AF-08 probably ameliorated pneumonia exacerbated by TBBPA exposure in RSV-infected mice by limiting excess cellular immune responses.

  5. Abiotic Bromination of Soil Organic Matter.

    Science.gov (United States)

    Leri, Alessandra C; Ravel, Bruce

    2015-11-17

    Biogeochemical transformations of plant-derived soil organic matter (SOM) involve complex abiotic and microbially mediated reactions. One such reaction is halogenation, which occurs naturally in the soil environment and has been associated with enzymatic activity of decomposer organisms. Building on a recent finding that naturally produced organobromine is ubiquitous in SOM, we hypothesized that inorganic bromide could be subject to abiotic oxidations resulting in bromination of SOM. Through lab-based degradation treatments of plant material and soil humus, we have shown that abiotic bromination of particulate organic matter occurs in the presence of a range of inorganic oxidants, including hydrogen peroxide and assorted forms of ferric iron, producing both aliphatic and aromatic forms of organobromine. Bromination of oak and pine litter is limited primarily by bromide concentration. Fresh plant material is more susceptible to bromination than decayed litter and soil humus, due to a labile pool of mainly aliphatic compounds that break down during early stages of SOM formation. As the first evidence of abiotic bromination of particulate SOM, this study identifies a mechanistic source of the natural organobromine in humic substances and the soil organic horizon. Formation of organobromine through oxidative treatments of plant material also provides insights into the relative stability of aromatic and aliphatic components of SOM.

  6. 21 CFR 180.30 - Brominated vegetable oil.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Brominated vegetable oil. 180.30 Section 180.30... Brominated vegetable oil. The food additive brominated vegetable oil may be safely used in accordance with... used on an interim basis as a stabilizer for flavoring oils used in fruit-flavored beverages, for...

  7. 40 CFR 721.9740 - Brominated triazine derivative.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Brominated triazine derivative. 721... Substances § 721.9740 Brominated triazine derivative. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as a brominated triazine...

  8. Plasma etching of cesium iodide

    International Nuclear Information System (INIS)

    Thick films of cesium iodide (CsI) are often used to convert x-ray images into visible light. Spreading of the visible light within CsI, however, reduces the resolution of the resulting image. Anisotropic etching of the CsI film into an array of micropixels can improve the image resolution by confining light within each pixel. The etching process uses a high-density inductively coupled plasma to pattern CsI samples held by a heated, rf-biased chuck. Fluorine-containing gases such as CF4 are found to enhance the etch rate by an order of magnitude compared to Ar+ sputtering alone. Without inert-gas ion bombardment, however, the CF4 etch becomes self-limited within a few microns of depth due to the blanket deposition of a passivation layer. Using CF4+Ar continuously removes this layer from the lateral surfaces, but the formation of a thick passivation layer on the unbombarded sidewalls of etched features is observed by scanning electron microscopy. At a substrate temperature of 220 deg. C, the minimum ion-bombardment energy for etching is Ei∼50 eV, and the rate depends on Ei1/2 above 65 eV. In dilute mixtures of CF4 and Ar, the etch rate is proportional to the gas-phase density of atomic fluorine. Above 50% CF4, however, the rate decreases, indicating the onset of net surface polymer deposition. These observations suggest that anisotropy is obtained through the ion-enhanced inhibitor etching mechanism. Etching exhibits an Arrhenius-type behavior in which the etch rate increases from ∼40 nm/min at 40 deg. C to 380 nm/min at 330 deg. C. The temperature dependence corresponds to an activation energy of 0.13±0.01 eV. This activation energy is consistent with the electronic sputtering mechanism for alkali halides

  9. PHONONS IN GRAPHITE INTERCALATED WITH BROMINE

    OpenAIRE

    Batallan, F.; Rosenman, I.; Simon, C; Furdin, G.; Lauter, H.

    1981-01-01

    We have investigated the phonon spectrum in stage 2 graphite intercalate with bromine by using inelastic neutron scattering. We have observed longitudinal and transverse phonons along the c direction as well as in the layer plane. Results are presented for energies up to 15 THz at 300 K. A linear chain model explains most of our results.

  10. Brominated flame retardants and endocrine disruption

    NARCIS (Netherlands)

    Vos, J.G.; Becher, G.; Berg, van den M.; Boer, de J.; Leonards, P.E.G.

    2003-01-01

    From an environmental point of view, an increasing important group of organohalogen compounds are the brominated flame retardants (BFRs), which are widely used in polymers and textiles and applied in construction materials, furniture, and electronic equipment. BFRs with the highest production volume

  11. Bromination of selected pharmaceuticals in water matrices.

    Science.gov (United States)

    Benitez, F Javier; Acero, Juan L; Real, Francisco J; Roldan, Gloria; Casas, Francisco

    2011-11-01

    The bromination of five selected pharmaceuticals (metoprolol, naproxen, amoxicillin, phenacetin, and hydrochlorothiazide) was studied with these compounds individually dissolved in ultra-pure water. The apparent rate constants for the bromination reaction were determined as a function of the pH, obtaining the sequence amoxicillin>naproxen>hydrochlorothiazide≈phenacetin≈metoprolol. A kinetic mechanism specifying the dissociation reactions and the species formed for each compound according to its pK(a) value and the pH allowed the intrinsic rate constants to be determined for each elementary reaction. There was fairly good agreement between the experimental and calculated values of the apparent rate constants, confirming the goodness of the proposed reaction mechanism. In a second stage, the bromination of the selected pharmaceuticals simultaneously dissolved in three water matrices (a groundwater, a surface water from a public reservoir, and a secondary effluent from a WWTP) was investigated. The pharmaceutical elimination trend agreed with the previously determined rate constants. The influence of the main operating conditions (pH, initial bromine dose, and characteristics of the water matrix) on the degradation of the pharmaceuticals was established. An elimination concentration profile for each pharmaceutical in the water matrices was proposed based on the use of the previously evaluated apparent rate constants, and the theoretical results agreed satisfactorily with experiment. Finally, chlorination experiments performed in the presence of bromide showed that low bromide concentrations slightly accelerate the oxidation of the selected pharmaceuticals during chlorine disinfection.

  12. The partitioning of iodides into steam

    International Nuclear Information System (INIS)

    In order to estimate the likely releases of radioactive iodine during steam generator tube rupture (SGTR) faults, it is necessary to know the relevant partition coefficients as a function of temperature and solution composition. It has been suggested previously that, under SGTR fault conditions, partitioning of free or ion-paired I- into the steam may be more extensive than that for molecular HI. This report uses available information on the partitioning of iodides and other salts to provide a means of estimating the partition coefficient of the iodide ion as a function of boric acid concentration and temperature. (author)

  13. Adsorption of radioactive iodide by natural zeolites

    International Nuclear Information System (INIS)

    Two natural zeolites from Iranian deposits (clinoptilolite and natrolite) were characterized and their ability for adsorption of iodide from nuclear wastewaters was evaluated. The adsorption behavior was studied on natural and modified zeolites by γ-spectrometry using 131I as radiotracer. Adsorption isotherms and distribution coefficient (Kd) were measured. The results showed that clinoptilolite is a more promising zeolite for removal of iodide compared to natrolite. Furthermore, the adsorption was higher in silver, lead and thallium forms, whereas the lowest desorption was observed in lead modified zeolite. (author)

  14. Electrochemical reaction rates in a dye sentisised solar cell - the iodide/tri-iodide redox system

    DEFF Research Database (Denmark)

    Bay, Lasse; West, Keld; Winter-Jensen, Bjørn;

    2006-01-01

    The electrochemical reaction rate of the redox couple iodide / tri-iodide in acetonitrile is characterised by impedance spectroscopy. Different electrode materials relevant for the function of dye-sensitised solar cells (DSSC) are investigated. Preferably, the reaction with the iodide / tri......), and polyaniline (PANI) - all deposited onto fluorine doped tin oxide (FTO) glass. Both Pt and PEDOT are found to have sufficiently high catalytic activities for practical use as counter electrode in DSSC. The reaction resistance on FTO and anatase confirmed the beneficial effect of a compact anatase layer on top...

  15. 21 CFR 184.1265 - Cuprous iodide.

    Science.gov (United States)

    2010-04-01

    ... the following specific limitations: Category of food Maximum treatment level in food Functional use... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Cuprous iodide. 184.1265 Section 184.1265 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR...

  16. Electronic and optical properties of lead iodide

    DEFF Research Database (Denmark)

    Ahuja, R.; Arwin, H.; Ferreira da Silva, A.;

    2002-01-01

    The electronic properties and the optical absorption of lead iodide (PbI2) have been investigated experimentally by means of optical absorption and spectroscopic ellipsometry, and theoretically by a full-potential linear muffin-tin-orbital method. PbI2 has been recognized as a very promising...

  17. Symproportionation versus Disproportionation in Bromine Redox Systems

    International Nuclear Information System (INIS)

    Graphical abstract: Display Omitted -- Highlights: • The disproportionation and symproportionation of bromine in different media is presented. • All the redox systems are elaborated according to the principles of the generalized approach to electrolytic redox systems (GATES/GEB). • All physicochemical knowledge is involved in the algorithm applied for this purpose. • The graphical representation of the systems is the basis of gaining the detailed physicochemical knowledge on the systems in question. -- Abstract: The paper refers to dynamic (titration) redox systems where symproportionation or disproportionation of bromine species occur. The related systems are modeled according to principles assumed in the Generalized Approach to Electrolytic Redox Systems (GATES), with Generalized Electron Balance (GEB) concept involved in the GATES/GEB software. The results obtained from calculations made with use of iterative computer programs prepared according to MATLAB computational software, are presented graphically, as 2D and 3D graphs

  18. Membrane-less hydrogen bromine flow battery

    CERN Document Server

    Braff, W A; Buie, C R

    2014-01-01

    In order for the widely discussed benefits of flow batteries for electrochemical energy storage to be applied at large scale, the cost of the electrochemical stack must come down substantially. One promising avenue for reducing stack cost is to increase the system power density while maintaining efficiency, enabling smaller stacks. Here we report on a membrane-less, hydrogen bromine laminar flow battery as a potential high power density solution. The membrane-less design enables power densities of 0.795 W cm$^{-2}$ at room temperature and atmospheric pressure, with a round-trip voltage efficiency of 92\\% at 25\\% of peak power. Theoretical solutions are also presented to guide the design of future laminar flow batteries. The high power density achieved by the hydrogen bromine laminar flow battery, along with the potential for rechargeable operation, will translate into smaller, inexpensive systems that could revolutionize the fields of large-scale energy storage and portable power systems.

  19. Cu-catalyzed trifluoromethylation of aryl iodides with trifluoromethylzinc reagent prepared in situ from trifluoromethyl iodide

    OpenAIRE

    Yuzo Nakamura; Motohiro Fujiu; Tatsuya Murase; Yoshimitsu Itoh; Hiroki Serizawa; Kohsuke Aikawa; Koichi Mikami

    2013-01-01

    The trifluoromethylation of aryl iodides catalyzed by copper(I) salt with trifluoromethylzinc reagent prepared in situ from trifluoromethyl iodide and Zn dust was accomplished. The catalytic reactions proceeded under mild reaction conditions, providing the corresponding aromatic trifluoromethylated products in moderate to high yields. The advantage of this method is that additives such as metal fluoride (MF), which are indispensable to activate silyl groups for transmetallation in the corresp...

  20. Oxidative treatment of bromide-containing waters: formation of bromine and its reactions with inorganic and organic compounds--a critical review.

    Science.gov (United States)

    Heeb, Michèle B; Criquet, Justine; Zimmermann-Steffens, Saskia G; von Gunten, Urs

    2014-01-01

    Bromide (Br(-)) is present in all water sources at concentrations ranging from ≈ 10 to >1000 μg L(-1) in fresh waters and about 67 mg L(-1) in seawater. During oxidative water treatment bromide is oxidized to hypobromous acid/hypobromite (HOBr/OBr(-)) and other bromine species. A systematic and critical literature review has been conducted on the reactivity of HOBr/OBr(-) and other bromine species with inorganic and organic compounds, including micropollutants. The speciation of bromine in the absence and presence of chloride and chlorine has been calculated and it could be shown that HOBr/OBr(-) are the dominant species in fresh waters. In ocean waters, other bromine species such as Br2, BrCl, and Br2O gain importance and may have to be considered under certain conditions. HOBr reacts fast with many inorganic compounds such as ammonia, iodide, sulfite, nitrite, cyanide and thiocyanide with apparent second-order rate constants in the order of 10(4)-10(9)M(-1)s(-1) at pH 7. No rate constants for the reactions with Fe(II) and As(III) are available. Mn(II) oxidation by bromine is controlled by a Mn(III,IV) oxide-catalyzed process involving Br2O and BrCl. Bromine shows a very high reactivity toward phenolic groups (apparent second-order rate constants kapp ≈ 10(3)-10(5)M(-1)s(-1) at pH 7), amines and sulfamides (kapp ≈ 10(5)-10(6)M(-1)s(-1) at pH 7) and S-containing compounds (kapp ≈ 10(5)-10(7)M(-1)s(-1) at pH 7). For phenolic moieties, it is possible to derive second-order rate constants with a Hammett-σ-based QSAR approach with [Formula in text]. A negative slope is typical for electrophilic substitution reactions. In general, kapp of bromine reactions at pH 7 are up to three orders of magnitude greater than for chlorine. In the case of amines, these rate constants are even higher than for ozone. Model calculations show that depending on the bromide concentration and the pH, the high reactivity of bromine may outweigh the reactions of chlorine during

  1. Electrochemical reaction rates in a dye-sensitised solar cell - the iodide/tri-iodide redox system

    DEFF Research Database (Denmark)

    Bay, L.; West, K.; Winther-Jensen, B.;

    2006-01-01

    The electrochemical reaction rate of the redox couple iodide/tri-iodide in acetonitrile is characterised by impedance spectroscopy. Different electrode materials relevant for the function of dye-sensitised solar cells (DSSC) are investigated. Preferably, the reaction with the iodide/tri-iodide co......The electrochemical reaction rate of the redox couple iodide/tri-iodide in acetonitrile is characterised by impedance spectroscopy. Different electrode materials relevant for the function of dye-sensitised solar cells (DSSC) are investigated. Preferably, the reaction with the iodide......), and polyaniline (PANI)-all deposited onto fluorine-doped tin oxide (FTO) glass. Both Pt and PEDOT are found to have sufficiently high catalytic activities for practical use as counter electrodes in DSSC. The reaction resistance on FTO and anatase confirmed the beneficial effect of a compact anatase layer on top...

  2. Brominated thiophenes as precursors in the preparation of brominated and arylated anthraquinones.

    Science.gov (United States)

    Thiemann, Thies; Tanaka, Yasuko; Iniesta, Jesus

    2009-01-01

    Brominated anthraquinones can be synthesized directly from bromothiophenes when these are reacted with 1,4-naphthoquinones in the presence of meta-chloroperoxybenzoic acid. The bromoanthraquinones are versatile building blocks in the preparation of arylated anthraquinones and of extended pi-systems with interspersed anthraquinone units. PMID:19305356

  3. Brominated Thiophenes as Precursors in the Preparation of Brominated and Arylated Anthraquinones

    Directory of Open Access Journals (Sweden)

    Thies Thiemann

    2009-03-01

    Full Text Available Brominated anthraquinones can be synthesized directly from bromothiophenes when these are reacted with 1,4-naphthoquinones in the presence of meta-chloroperoxybenzoic acid. The bromoanthraquinones are versatile building blocks in the preparation of arylated anthraquinones and of extended π-systems with interspersed anthraquinone units.

  4. Brominated Thiophenes as Precursors in the Preparation of Brominated and Arylated Anthraquinones

    OpenAIRE

    Thies Thiemann; Jesus Iniesta; Yasuko Tanaka

    2009-01-01

    Brominated anthraquinones can be synthesized directly from bromothiophenes when these are reacted with 1,4-naphthoquinones in the presence of meta-chloroperoxybenzoic acid. The bromoanthraquinones are versatile building blocks in the preparation of arylated anthraquinones and of extended π-systems with interspersed anthraquinone units.

  5. Polyvinylpolypyrrolidone-bromine complex: Mild and efficient polymeric reagent for bromination of activated aromatic compounds

    Institute of Scientific and Technical Information of China (English)

    Masoud Mokhtary; Moslem M. Lakouraj

    2011-01-01

    Mild and efficient method for bromination of electron-rich aromatic compounds is described using polyvinylpolypyrrolidonebromine complex (PVPP-Br2). The reaction proceeded smoothly with phenols and N,N-alkylated amines to afford the corresponding monobrominated product in good yields at ambient temperature.

  6. Composition and properties of thallium mercury iodide

    Science.gov (United States)

    Kennedy, John H.; Schaupp, Christopher; Yang, Yuan; Zhang, Zhengming; Novinson, Thomas; Hoffard, Theresa

    1990-10-01

    Conflicting reports exist in the literature concerning the composition of thallium mercury iodide. Solid state synthesis with HgI 2 and TlI has been reported to give Tl 4HgI 6 while synthesis from solution has been reported to give Tl 2HgI 4. In this report we show that the "orange compound" precipitating from solution is actually a 1:1 mole ratio mixture of Tl 4HgI 6 and HgI 2. Pure Tl 4HgI 6, which is yellow, can be produced by heating the mixture at 100°C for several days to volatilize HgI 2 or more simply, by adding Tl(I) to a solution containing 2:1 KI:K 2HgI 4 to provide the additional iodide ions needed for Tl 4HgI 6. Tl 4HgI 6, unlike Ag 2HgI 4 and Cu 2HgI 4, has no sharp thermochromic changes and has no measurable ionic conductivity. This provides another example of the significant role the metal ion plans in determining structure and properties of metal mercury iodide compounds.

  7. Formation of cyanogen iodide by lactoperoxidase.

    Science.gov (United States)

    Schlorke, Denise; Flemmig, Jörg; Birkemeyer, Claudia; Arnhold, Jürgen

    2016-01-01

    The haem protein lactoperoxidase (LPO) is an important component of the anti-microbial immune defence in external secretions and is also applied as preservative in food, oral care and cosmetic products. Upon oxidation of SCN(-) and I(-) by the LPO-hydrogen peroxide system, oxidised species are formed with bacteriostatic and/or bactericidal activity. Here we describe the formation of the inter(pseudo)halogen cyanogen iodide (ICN) by LPO. This product is formed when both, thiocyanate and iodide, are present together in the reaction mixture. Using (13)C nuclear magnetic resonance spectroscopy and gas chromatography-mass spectrometry we could identify this inter(pseudo)halogen after applying iodide in slight excess over thiocyanate. The formation of ICN is based on the reaction of oxidised iodine species with thiocyanate. Further, we could demonstrate that ICN is also formed by the related haem enzyme myeloperoxidase and, in lower amounts, in the enzyme-free system. As I(-) is not competitive for SCN(-) under physiologically relevant conditions, the formation of ICN is not expected in secretions but may be relevant for LPO-containing products.

  8. Fire-retardant coatings based on organic bromine/phenoxy or brominated epoxy systems

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, D.M.; Chiu, Ing L.

    1989-06-01

    Thin phenoxy and brominated epoxy/curing agent films were prepared by solvent casting on Mylar and Kapton. Thicknesses were approximated assuming volume additivity. Important parameters were uniformity of thickness, distribution of the bromine-containing fire retardant, adhesion to carrier substrate (either Mylar or Kapton), and uniformity of the coating, i.e., absence of pinholes, blush, blistering, etc. Wetting behavior was modified using fluoro, silicone or polyurea surfactants. Several solvent systems were examined and a ternary solvent system was ultimately used. Distribution of fire-retardant bromine was analyzed using electron microprobe, x-ray fluorescence and wet chemical methods. Significant discrepancies in the /mu/m-scale analyses of the microprobe measurements have not been resolved. Some of the brominated fire retardants were insoluble in the resin systems and the phase separation was immediately obvious. Similarly, some of the crystallizable epoxies could not be cast easily into homogeneous, amorphous films. Castings were made on a standard 8'' /times/ 10'' aluminum vacuum plate polished with jeweler's rouge prior to every casting. Solvent was removed in a forced air or vacuum oven. Removal and/or curing was accelerated with temperature. The fire-retardant bromine was required to be stable in alcohol/salt solutions. Final formulation used after a significant amount of testing was phenoxy resin PKHC in a ternary solvent system composed of methylethyl ketone, cellosolve acetate and toluene. Tetrabromobisphenol A was used as the flame retardant with FC-430 as surfactant. The dying schedule was 30 minutes at 150/degree/C. 4 refs., 6 figs., 3 tabs.

  9. Formation of THMs and HANs during bromination of Microcystis aeruginosa

    Institute of Scientific and Technical Information of China (English)

    Yunzhu Pu; Lingzhao Kong; Xin Huang; Guoji Ding; Naiyun Gao

    2013-01-01

    Bromine-contained disinfectants and biocides are widely used in swimming pools,recreational waters and cooling towers.The objective of this study was to evaluate the formation of thrihalomethanes (THMs) and haloacetonitriles (HANs) and their cytotoxicity in algae solutions during free bromine disinfection.Disinfection by-products formation potential experiments were conducted using modelsolutions containing 7mg/L (as total organic carbon) Microcystis aeruginosa cells.Effects of free bromine dosage,pH and ammonia were investigated.The results showed that brominated disinfection by-products were the major products when free bromine was applied.The total THMs formed during bromination was much as that formed during chlorination,whereas HANs were elevated by using bromination instead of chlorination.Dibromoacetonitrice (C2H2NBr2) and bromoform (CHBr3) were the only detected species during free bromine disinfection.The production of C2H2NBr2 and CHBr3 increased with disinfectant dosage but decreased with dosing ammonia.CHBr3 increased with the pH changing from 5 to 9.However,C2H2NBr2 achieved the highest production at neutral pH,which was due to a joint effect of variation in hydrolysis rate and free bromine reactivity.The hydrolysis of C2H2NBr2 was basecatalytic and nearly unaffected by disinfectant.Finally,estimation of cytotoxicity of the disinfected algae solutions showed that HANs formation was responsible for the majority of toxicity.Considering its highest toxicity among the measured disinfection by-products,the elevated C2H2NBr2 should be considered when using bromine-related algaecide.

  10. New infrared spectroscopic database for bromine nitrate

    Science.gov (United States)

    Wagner, Georg; Birk, Manfred

    2016-08-01

    Fourier transform infrared measurements of bromine nitrate have been performed in the spectral region 675-1400 cm-1 at 0.014 cm-1 spectral resolution. Absorption cross sections were derived from 38 spectra covering the temperature range from 203 to 296 K and air pressure range from 0 to 190 mbar. For line-by-line analysis, further spectra were recorded at 0.00094 cm-1 spectral resolution at 223 and 293 K. The sample was synthesized from ClONO2 and Br2. Band strengths of the bands ν3 around 803 cm-1 and ν2 around 1286 cm-1 were determined from three pure BrONO2 measurements at different temperatures and pressures. Number densities in the absorption cell were derived from pressure measurements of the purified sample taking into account small amounts of impurities determined spectroscopically. Resulting band strengths are Sν3 = 2.872(52) × 10-17 cm2 molec-1 cm-1 and Sν2 = 3.63(15) × 10-17 cm2 molec-1 cm-1. Absorption cross sections of all measurements were scaled to these band strengths. Further data reduction was achieved with an interpolation scheme based on two-dimensional polynomials in ln(pressure) and temperature. The database is well-suited for remote-sensing application and should reduce the atmospheric bromine nitrate error budget substantially.

  11. Effect of nitrogen and oxygen on radiolysis of iodide solution

    Energy Technology Data Exchange (ETDEWEB)

    Karasawa, H.; Endo, M. [Hitachi Ltd., Power and Industrial System R+D Divisions, Ibaraki (Japan)

    1996-12-01

    The effect of nitrogen and oxygen on radiolysis of iodide solution was examined. Direct decomposition of nitrogen by {gamma}-radiation produced nitric acid to decrease a water pH. This resulted in the iodine formation in the radiolysis of iodide solution. Hydrogen peroxide was produced by the radiolysis of water containing oxygen. This worked a reducing agent to suppress the formation of iodine in the radiolysis of iodide solution. In the analytical model, fourteen iodine species were considered and reaction scheme consisted in 124 reactions. The analytical model could estimate the oxidation state of iodide ions. (author) 4 figs., 4 refs.

  12. Mercuric Iodide Anticoincidence Shield for Gamma-Ray Spectrometer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We utilize a new detector material, polycrystalline mercuric iodide, for background suppression by active anticoincidence shielding in gamma-ray spectrometers. Two...

  13. Mercuric Iodide Anticoincidence Shield for Gamma-Ray Spectrometer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to utilize a new detector material, polycrystalline mercuric iodide, for background suppression by active anticoincidence shielding in gamma-ray...

  14. Europium-doped barium bromide iodide

    Energy Technology Data Exchange (ETDEWEB)

    Gundiah, Gautam; Hanrahan, Stephen M.; Hollander, Fredrick J.; Bourret-Courchesne, Edith D.

    2009-10-21

    Single crystals of Ba0.96Eu0.04BrI (barium europium bromide iodide) were grown by the Bridgman technique. The title compound adopts the ordered PbCl2 structure [Braekken (1932). Z. Kristallogr. 83, 222-282]. All atoms occupy the fourfold special positions (4c, site symmetry m) of the space group Pnma with a statistical distribution of Ba and Eu. They lie on the mirror planes, perpendicular to the b axis at y = +-0.25. Each cation is coordinated by nine anions in a tricapped trigonal prismatic arrangement.

  15. Novel mercuric iodide polycrystalline nuclear particles counters

    Energy Technology Data Exchange (ETDEWEB)

    Schieber, M. [Hebrew Univ. of Jerusalem (Israel)]|[Sandia National Lab., Livermore, CA (United States); Zuck, A.; Braiman, M.; Nissenbaum, J. [Hebrew Univ. of Jerusalem (Israel)] [and others

    1996-12-31

    Polycrystalline mercuric iodide nuclear radiation detectors having areas between 0.01 to 100 cm{sup 2} and thicknesses 30 to 600 microns, have been fabricated with single, linear strip and square pixel contact. The large area detectors 10 to 600 cm{sup 2} were produced by industrial ceramic equipment while the smaller ones, about 1 cm{sup 2} area, were produced in the laboratory. The large detectors still had large leakage currents and the production process is being revised. The smaller detectors were tested and their response to lower and higher gamma energy, beta and even 100 GeV muons at CERN will be reported.

  16. Large-area mercuric iodide photodetectors

    International Nuclear Information System (INIS)

    This article discusses the limits of the active area of mercuric iodide photodetectors imposed by the size of available crystals, electronic noise, and the uniformity of charge carrier collection. Theoretical calculations of the photodetector electronic noise are compared with the experimental results. Different entrance contacts were studied including semitransparent palladium films and conductive liquids. HgI2 photodetectors with active area up to 4 sq cm are matched with NaI(Tl) and CsI(Tl) scintillation crystals and are evaluated as gamma radiation spectrometers

  17. Transfer of the human sodium/iodide symporter gene enhances iodide uptake in melanoma cells

    International Nuclear Information System (INIS)

    Objective: To obtain human sodium/iodide symporter (hNIS) cDNA and to study its biological property and potential use as a therapeutic radioiodide for melanoma. Methods: hNIS gene cDNA was amplified with total RNA from human thyroid tissue by RT-PCR. The hNIS cDNA was inserted into cloning vector pUCm-T and subcloned into eukaryotic expression vector pcDNA3. The recombinant plasmid pcDNA3-hNIS was introduced into B16 cells using the electroporation technique. The uptake and efflux of iodide was examined in vitro. Results: The cloned hNIS cDNA sequence was identical to the published sequence. Two novel cell lines named B16-A containing hNIS and B16-B containing pcDNA3 only were established. The resultant cell line B16-A accumulated 17 and 19 times more radioiodide in vitro than B16 and B16-B did, respectively. However the efflux of iodide from B16-A was also rapid ( T1/2=10 min). Conclusions: Our preliminary data indicate that the transduction of the hNIS gene per se is sufficient to induce iodide transport in melanoma cells in vitro, but its T1/2 is short. With regard to therapeutic application, however, further investigation is necessary so as to develop a method of maintaining more radioiodide in the cells for long enough to produce greater therapeutic effects

  18. Use of Bromine and Bromo-Organic Compounds in Organic Synthesis.

    Science.gov (United States)

    Saikia, Indranirekha; Borah, Arun Jyoti; Phukan, Prodeep

    2016-06-22

    Bromination is one of the most important transformations in organic synthesis and can be carried out using bromine and many other bromo compounds. Use of molecular bromine in organic synthesis is well-known. However, due to the hazardous nature of bromine, enormous growth has been witnessed in the past several decades for the development of solid bromine carriers. This review outlines the use of bromine and different bromo-organic compounds in organic synthesis. The applications of bromine, a total of 107 bromo-organic compounds, 11 other brominating agents, and a few natural bromine sources were incorporated. The scope of these reagents for various organic transformations such as bromination, cohalogenation, oxidation, cyclization, ring-opening reactions, substitution, rearrangement, hydrolysis, catalysis, etc. has been described briefly to highlight important aspects of the bromo-organic compounds in organic synthesis.

  19. Production of Molecular Iodine and Tri-iodide in the Frozen Solution of Iodide: Implication for Polar Atmosphere.

    Science.gov (United States)

    Kim, Kitae; Yabushita, Akihiro; Okumura, Masanori; Saiz-Lopez, Alfonso; Cuevas, Carlos A; Blaszczak-Boxe, Christopher S; Min, Dae Wi; Yoon, Ho-Il; Choi, Wonyong

    2016-02-01

    The chemistry of reactive halogens in the polar atmosphere plays important roles in ozone and mercury depletion events, oxidizing capacity, and dimethylsulfide oxidation to form cloud-condensation nuclei. Among halogen species, the sources and emission mechanisms of inorganic iodine compounds in the polar boundary layer remain unknown. Here, we demonstrate that the production of tri-iodide (I3(-)) via iodide oxidation, which is negligible in aqueous solution, is significantly accelerated in frozen solution, both in the presence and the absence of solar irradiation. Field experiments carried out in the Antarctic region (King George Island, 62°13'S, 58°47'W) also showed that the generation of tri-iodide via solar photo-oxidation was enhanced when iodide was added to various ice media. The emission of gaseous I2 from the irradiated frozen solution of iodide to the gas phase was detected by using cavity ring-down spectroscopy, which was observed both in the frozen state at 253 K and after thawing the ice at 298 K. The accelerated (photo-)oxidation of iodide and the subsequent formation of tri-iodide and I2 in ice appear to be related with the freeze concentration of iodide and dissolved O2 trapped in the ice crystal grain boundaries. We propose that an accelerated abiotic transformation of iodide to gaseous I2 in ice media provides a previously unrecognized formation pathway of active iodine species in the polar atmosphere.

  20. Bromine content and brominated flame retardants in food and animal feed from the UK.

    Science.gov (United States)

    Fernandes, A R; Mortimer, D; Rose, M; Smith, F; Panton, S; Garcia-Lopez, M

    2016-05-01

    Current occurrence data for polybrominated diphenyl ethers (PBDE) and hexa-bromocyclododecane (HBCD) measured in most commonly consumed foods (n = 156) and animal feeds (n = 51) sampled in the UK, demonstrates an ongoing ubiquity of these contaminants in human and animal diets. PBDE concentrations for the sum of 17 measured congeners ranged from 0.02 ng/g to 8.91 ng/g whole weight for food, and 0.11 ng/g to 9.63 ng/g whole weight for animal feeds. The highest concentration ranges, and mean values were detected in fish, processed foods and fish feeds. HBCD diastereomers (alpha-HBCD was the most commonly detected) generally occurred at lower concentrations (from animal feed) and less frequently than PBDEs, but tetrabromobisphenol A which was also measured, was rarely detected. The total bromine content of the samples was also determined in an attempt to use a mass balance approach to investigate some of these samples for the occurrence of novel and emerging BFRs. Although the approach was further refined by measuring organic bromine content, the concentrations of bromine were too high (in most cases by orders of magnitude) to allow use of the approach. A selected sub-set of samples was screened by GC-MS, for the presence of novel/emerging brominated flame retardants (PBT, TBX, PBEB, DBHCTD, HCTBPH and OBTMPI) but these were not detected at the higher limits of detection that result from full scan (GC-MS) screening. This data will contribute to the EU wide risk assessment on these contaminants.

  1. Ruthenium-Catalyzed meta-Selective C—H Bromination

    Science.gov (United States)

    Teskey, Christopher J; Lui, Andrew Y W; Greaney, Michael F

    2015-01-01

    The first example of a transition-metal-catalyzed, meta-selective C–H bromination procedure is reported. In the presence of catalytic [{Ru(p-cymene)Cl2}2], tetrabutylammonium tribromide can be used to functionalize the meta C–H bond of 2-phenylpyridine derivatives, thus affording difficult to access products which are highly predisposed to further derivatization. We demonstrate this utility with one-pot bromination/arylation and bromination/alkenylation procedures to deliver meta-arylated and meta-alkenylated products, respectively, in a single step. PMID:26288217

  2. Ruthenium-Catalyzed meta-Selective C—H Bromination

    OpenAIRE

    Teskey, Christopher J; Lui, Andrew Y W; Greaney, Michael F.

    2015-01-01

    The first example of a transition-metal-catalyzed, meta-selective C–H bromination procedure is reported. In the presence of catalytic [{Ru(p-cymene)Cl2}2], tetrabutylammonium tribromide can be used to functionalize the meta C–H bond of 2-phenylpyridine derivatives, thus affording difficult to access products which are highly predisposed to further derivatization. We demonstrate this utility with one-pot bromination/arylation and bromination/alkenylation procedures to deliver meta-arylated and...

  3. Phase 2 Methyl Iodide Deep-Bed Adsorption Tests

    Energy Technology Data Exchange (ETDEWEB)

    Soelberg, Nick [Idaho National Lab. (INL), Idaho Falls, ID (United States); Watson, Tony [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2014-09-01

    Nuclear fission produces fission products (FPs) and activation products, including iodine-129, which could evolve into used fuel reprocessing facility off-gas systems, and could require off-gas control to limit air emissions to levels within acceptable emission limits. Research, demonstrations, and some reprocessing plant experience have indicated that diatomic iodine can be captured with efficiencies high enough to meet regulatory requirements. Research on the capture of organic iodides has also been performed, but to a lesser extent. Several questions remain open regarding the capture of iodine bound in organic compounds. Deep-bed methyl iodide adsorption testing has progressed according to a multi-laboratory methyl iodide adsorption test plan. This report summarizes the second phase of methyl iodide adsorption work performed according to this test plan using the deep-bed iodine adsorption test system at the Idaho National Laboratory (INL), performed during the second half of Fiscal Year (FY) 2014. Test results continue to show that methyl iodide adsorption using AgZ can achieve total iodine decontamination factors (DFs, ratios of uncontrolled and controlled total iodine levels) above 1,000, until breakthrough occurred. However, mass transfer zone depths are deeper for methyl iodide adsorption compared to diatomic iodine (I2) adsorption. Methyl iodide DFs for the Ag Aerogel test adsorption efficiencies were less than 1,000, and the methyl iodide mass transfer zone depth exceeded 8 inches. Additional deep-bed testing and analyses are recommended to (a) expand the data base for methyl iodide adsorption under various conditions specified in the methyl iodide test plan, and (b) provide more data for evaluating organic iodide reactions and reaction byproducts for different potential adsorption conditions.

  4. Magnetic Trapping of Cold Bromine Atoms

    CERN Document Server

    Rennick, C J; Doherty, W G; Softley, T P

    2014-01-01

    Magnetic trapping of bromine atoms at temperatures in the milliKelvin regime is demonstrated for the first time. The atoms are produced by photodissociation of Br$_2$ molecules in a molecular beam. The lab-frame velocity of Br atoms is controlled by the wavelength and polarization of the photodissociation laser. Careful selection of the wavelength results in one of the pair of atoms having sufficient velocity to exactly cancel that of the parent molecule, and it remains stationary in the lab frame. A trap is formed at the null point between two opposing neodymium permanent magnets. Dissociation of molecules at the field minimum results in the slowest fraction of photofragments remaining trapped. After the ballistic escape of the fastest atoms, the trapped slow atoms are only lost by elastic collisions with the chamber background gas. The measured loss rate is consistent with estimates of the total cross section for only those collisions transferring sufficient kinetic energy to overcome the trapping potential...

  5. Dissolution of gaseous methyl iodide into aqueous sodium hydroxide solutions

    International Nuclear Information System (INIS)

    Absorption process of gaseous methyl iodide by water or sodium hydroxide solutions was investigated using a semi-flow type experimental apparatus by measuring the concentration of all measurable chemical species in both the gas and the liquid phase. The experimental temperature ranged from 288 to 311 K and the gaseous methyl iodide and aqueous sodium hydroxide concentrations were approximately 0.6 x 10-3 to 7 x 10-3 and 0 to 0.2 mol/dm3, respectively. It is estimated that the dissolution of methyl iodide into the sodium hydroxide solution proceeds according to the following steps. Step (1) Methyl iodide in air dissolves physically into the aqueous phase. Physical dissolution process obeys Henry's law. Step (2) Methyl iodide dissolved into the aqueous phase is decomposed by a base catalytic hydrolysis and produces methyl alcohol and iodide ion. The equilibrium constants of physical dissolution were obtained from the steady concentration in both the gas and the liquid phases in the semi-flow type experiment because the hydrolysis reaction rate of methyl iodide is very slow in comparison with the physical dissolution in this experimental conditions. The obtained value of the standard heat of solution of methyl iodide into water was 7.2 kcal/mol. Salting-out effect was observed when the concentration of sodium hydroxide in the absorbent was over 0.01 mol/dm3. (auth.)

  6. The metabolism and de-bromination of bromotyrosine in vivo

    NARCIS (Netherlands)

    A.R. Mani (Ali); J.C. Moreno (José C.); T.J. Visser (Theo J.); K.P. Moore (Kevin P.)

    2016-01-01

    textabstractDuring inflammation, leukocyte-derived eosinophil peroxidase catalyses the formation of hypobromous acid, which can brominate tyrosine residues in proteins to form bromotyrosine. Since eosinophils are involved in the pathogenesis of allergic reactions, such as asthma, urinary bromotyrosi

  7. Novel mercuric iodide polycrystalline nuclear particle counters

    Energy Technology Data Exchange (ETDEWEB)

    Schieber, M. [Hebrew Univ. of Jerusalem (Israel)]|[Sandia National Labs., Livermore, CA (United States); Zuck, A.; Braiman, M.; Nissenbaum, J. [Hebrew Univ. of Jerusalem (Israel); Turchetta, R.; Dulinski, W.; Husson, D.; Riester, J.L. [LEPSI, Strasbourg (France)

    1997-12-01

    Polycrystalline mercuric iodide nuclear radiation detectors have been produced in a novel technology. Unlike the normal single-crystal technology, there is no intrinsic limit to the surface on which these detectors can be produced. Detectors with areas up to about 1.5 cm{sup 2}, thicknesses from 30 to 600 {micro}m, and with single electrodes as well as microstrip and pixel contacts have been fabricated and successfully tested with photons in the range of 40--660 keV, {beta} particle`s emitted from a Sr-Y source, and high energy (100 GeV) muons. Results on both charge collection and counting efficiency are reported as well as some very preliminary imaging results. The experimental results on charge collection have been compared with simulation, and a combined {mu}{tau} product 10{sup {minus}7} cm{sup 2}/V for electrons has been estimated.

  8. Ferroelastic Fingerprints in Methylammonium Lead Iodide Perovskite

    KAUST Repository

    Hermes, Ilka M.

    2016-02-12

    Methylammonium lead iodide (MAPbI3) perovskite materials show an outstanding performance in photovoltaic devices. However, certain material properties, especially the possible ferroic behavior, remain unclear. We observed distinct nanoscale periodic domains in the piezoresponse of MAPbI3(Cl) grains. The structure and the orientation of these striped domains indicate ferroelasticity as their origin. By correlating vertical and lateral piezoresponse force microscopy experiments performed at different sample orientations with x-ray diffraction, the preferred domain orientation was suggested to be the a1-a2-phase. The observation of these ferroelastic fingerprints appears to strongly depend on the film texture and thus the preparation route. The formation of the ferroelastic twin domains could be induced by internal strain during the cubic-tetragonal phase transition.

  9. Conserved charged amino acid residues in the extracellular region of sodium/iodide symporter are critical for iodide transport activity

    Directory of Open Access Journals (Sweden)

    Liang Ji-An

    2010-11-01

    Full Text Available Abstract Background Sodium/iodide symporter (NIS mediates the active transport and accumulation of iodide from the blood into the thyroid gland. His-226 located in the extracellular region of NIS has been demonstrated to be critical for iodide transport in our previous study. The conserved charged amino acid residues in the extracellular region of NIS were therefore characterized in this study. Methods Fourteen charged residues (Arg-9, Glu-79, Arg-82, Lys-86, Asp-163, His-226, Arg-228, Asp-233, Asp-237, Arg-239, Arg-241, Asp-311, Asp-322, and Asp-331 were replaced by alanine. Iodide uptake abilities of mutants were evaluated by steady-state and kinetic analysis. The three-dimensional comparative protein structure of NIS was further modeled using sodium/glucose transporter as the reference protein. Results All the NIS mutants were expressed normally in the cells and targeted correctly to the plasma membrane. However, these mutants, except R9A, displayed severe defects on the iodide uptake. Further kinetic analysis revealed that mutations at conserved positively charged amino acid residues in the extracellular region of NIS led to decrease NIS-mediated iodide uptake activity by reducing the maximal rate of iodide transport, while mutations at conserved negatively charged residues led to decrease iodide transport by increasing dissociation between NIS mutants and iodide. Conclusions This is the first report characterizing thoroughly the functional significance of conserved charged amino acid residues in the extracellular region of NIS. Our data suggested that conserved charged amino acid residues, except Arg-9, in the extracellular region of NIS were critical for iodide transport.

  10. The Effect on Sodium/Iodide Symporter and Pendrin in Thyroid Colloid Retention Developed by Excess Iodide Intake.

    Science.gov (United States)

    Chen, Xiao-Yi; Lin, Chu-Hui; Yang, Li-Hua; Li, Wang-Gen; Zhang, Jin-Wei; Zheng, Wen-Wei; Wang, Xiang; Qian, Jiang; Huang, Jia-Luan; Lei, Yi-Xiong

    2016-07-01

    It is well known that excess iodide can lead to thyroid colloid retention, a classic characteristic of iodide-induced goiter. However, the mechanism has not been fully unrevealed. Iodide plays an important role in thyroid function at multiple steps of thyroid colloid synthesis and transport among which sodium/iodide symporter (NIS) and pendrin are essential. In our study, we fed female BALB/c mice with different concentrations of high-iodine water including group A (control group, 0 μg/L), group B (1500 μg/L), group C (3000 μg/L), group D (6000 μg/L), and group E (12,000 μg/L). After 7 months of feeding, we found that excess iodide could lead to different degrees of thyroid colloid retention. Besides, NIS and pendrin expression were downregulated in the highest dose group. The thyroid iodide intake function detected by urine iodine assay and thyroidal (125)I experiments showed that the urine level of iodine increased, while the iodine intake rate decreased when the concentration of iodide used in feeding water increased (all p control group). In addition, transmission electron microscopy (TEM) indicated a reduction in the number of intracellular mitochondria of thyroid cells. Based on these findings, we concluded that the occurrence of thyroid colloid retention exacerbated by excess iodide was associated with the suppression of NIS and pendrin expression, providing an additional insight of the potential mechanism of action of excess iodide on thyroid gland. PMID:26660892

  11. Expression of the human sodium/iodide symporter (hNIS) in xenotransplanted human thyroid carcinoma

    NARCIS (Netherlands)

    Smit, J.W.A.; Schröder - van der Elst, J.P.; Karperien, M.; Que, I.; Romijn, J.A.; Heide, van der D.

    2001-01-01

    The uptake of iodide in thyroid epithelial cells is mediated by the sodium/iodide symporter (NIS). The uptake of iodide is of vital importance for thyroid physiology and is a prerequisite for radioiodine therapy in thyroid cancer. Loss of iodide uptake due to diminished expression of the human NIS (

  12. Probing the tropical tropopause layer for organic and inorganic bromine

    Science.gov (United States)

    Werner, Bodo; Pfeilsticker, Klaus; Atlas, Elliot; Cheung, Ross; Chipperfield, Martyn; Colosimo, Fedele; Deutschmann, Tim; Elkins, Jim; Fahey, David; Feng, Wu; Festa, James; Gao, Ru-Shan; Hossaini, Ryan; Navarro, Maria; Raecke, Rasmus; Scalone, Lisa; Spolaor, Max; Thornberry, Troy; Tsai, Catalina; Stutz, Jochen

    2016-04-01

    Bromine chemistry impacts the levels of ozone in the upper troposphere and the stratosphere. An accurate quantitative understanding of the sources, sinks, and chemical transformation of bromine species is thus important to understand the photochemistry and budget of bromine in the tropical upper troposphere, tropopause layer and lowermost stratosphere (UT/TTL/LS). These regions are also known to serve as a gateway for delivery of ozone depleting gases to the stratosphere. CH3Br, halons, short-lived organic bromine precursors (VSLS), such as CHBr3, CH2Br2, and possibly inorganic product gases have been identified as the main bromine gases delivered to the stratosphere. However, many important details of the transport and delivery of VSLS and inorganic bromine compounds through the TTL are still uncertain. Moreover, a number of chemical processes, including the transformation of the source gases and cycling of inorganic bromine species at low ambient temperature and on ice particles are also poorly understood. The presentation reports measurements of CH4, O3, NO2, and BrO performed by different instruments and techniques during the 2013 NASA-ATTREX flights in the TTL and LS. The interpretation of our measurements is supported by chemical transport model (SLIMCAT) simulations. SLIMCAT results, in conjunction with extensive radiative transfer calculations using the Monte Carlo model McArtim, also are used to improve retrieval of O3, NO2, and BrO concentrations from limb scattered sunlight measurements made with the Differential Optical Absorption Spectroscopy (DOAS) technique during ATTREX. The chemical transport model also allows us to attribute observed concentration variations to transport and to photochemical processes. When properly accounting for the transport-related concentration variations in methane and ozone, we find that measured BrO mostly agrees with model simulations. An exception are regions where the contribution of the short-lived CH2Br2 or the

  13. Bromine pretreated chitosan for adsorption of lead (II) from water

    Indian Academy of Sciences (India)

    Rajendra Dongre; Minakshi Thakur; Dinesh Ghugal; Jostna Meshram

    2012-10-01

    Pollution by heavy metals like lead (II) is responsible for health hazards and environmental degradation. Adsorption is a prevalent method applied for removal of heavy metal pollutants from water. This study explored adsorption performances of 30% bromine pretreated chitosan for lead (II) abatement from water. Bromine pretreatment alters porosity and specific surface area of chitosan by means of physicochemical interaction with cationic sites of chitosan skeleton, besides imparting anionic alteration at amino linkages of chitosan, to remove lead (II) by chemical interactions on superfluous active sites as characterized by FTIR, SEM, DTA and elemental analysis. Lead adsorptions were studied in batch mode by varying parameters viz. pH, bromine loading, sorbent dosage, initial lead concentration, contact time and temperature. The adsorption equilibrium data was well fitted to Freundlich isotherm and maximum sorption capacity of 30% bromine pretreated chitosan sorbent was 1.755 g/kg with 85–90% lead removal efficiency. Though cost and applicability of sorbent is unproven, yet contrast to raw chitosan derivatives, activated carbons and some resins, 30% bromine pretreated chitosan endow benign and efficient lead abatement technique.

  14. Improved Stability of Mercuric Iodide Detectors for Anticoincidence Shields Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to utilize guard ring electrode structures and a new film growth technique to create improved polycrystalline mercuric iodide detectors for background...

  15. Levels and trends of brominated flame retardants in the European environment

    NARCIS (Netherlands)

    Law, R.J.; Allchin, C.R.; Boer, de J.; Covaci, A.; Herzke, D.; Lepom, P.; Morris, S.; Tronczynski, J.; Wit, de C.A.

    2006-01-01

    In this paper, we review those data which have recently become available for brominated flame retardants (particularly the brominated diphenyl ethers (BDEs) and hexabromocyclododecane (HBCD)) in samples from the European environment. Environmental compartments studied comprise the atmosphere, sedime

  16. Prevention of organic iodide formation in BWR`s

    Energy Technology Data Exchange (ETDEWEB)

    Karjunen, T. [Finnish Centre for Radiation and Nuclear Safety, Helsinki (Finland); Laitinen, T.; Piippo, J.; Sirkiae, P. [VTT Manufacturing Technology (Finland)

    1996-12-01

    During an accident, many different forms of iodine may emerge. Organic iodides, such as methyl iodide and ethyl iodide, are relatively volatile, and thus their appearance leads to increased concentration of gaseous iodine. Since organic iodides are also relatively immune to most accident mitigation measures, such as sprays and filters, they can affect the accident source term significantly even when only a small portion of iodine is in organic form. Formation of organic iodides may not be limited by the amount of organic substances available. Excessive amounts of methane can be produced, for example, during oxidation of boron carbide, which is used in BWR`s as a neutron absorber material. Another important source is cable insulation. In a BWR, a large quantity of cables is placed below the pressure vessel. Thus a large quantity of pyrolyse gases will be produced, should the vessel fail. Organic iodides can be formed as a result of many different reactions, but at least in certain conditions the main reaction takes place between an organic radical produced by radiolysis and elemental iodine. A necessary requirement for prevention of organic iodide production is therefore that the pH in the containment water pools is kept high enough to eliminate formation of elemental iodine. In a typical BWR the suppression pool water is usually unbuffered. As a result, the pH may be dominated by chemicals introduced during an accident. If no system for adding basic chemicals is operable, the main factor affecting pool water pH may be hydrochloric acid released during cable degradation. Should this occur, the conditions could be very favorable for production of elemental iodine and, consequently, formation of organic iodides. Although high pH is necessary for iodine retention, it could have also adverse effects. High pH may, for example, accelerate corrosion of containment materials and alter the characteristics of the solid corrosion products. (author) 6 figs., 1 tab., 13 refs.

  17. A review of polytypism in lead iodide

    Energy Technology Data Exchange (ETDEWEB)

    Beckmann, P.A. [Department of Physics, Bryn Mawr College, Bryn Mawr, Pennsylvania (United States)

    2010-05-15

    Lead Iodide (PbI{sub 2}) is an important inorganic solid for both basic scientific research and possible technological applications and in this brief review we discuss the structure of PbI{sub 2}. Although the basic structure is a simple I-Pb-I layered structure with a[PbI{sub 6}]{sup 4-} near-octahedron being the basic building block, there are many ways of stacking the layers which results in many polytypes. We present 20 of the 23 entries for the structure of PbI{sub 2} from the Inorganic Structural Database and order them by polytype. This represents more than 80 years of crystallographic research in the structure of this compound. We present a simple way to view the 2H, 4H, 6H, and 6R polytypes and extend the procedure to higher-order polytypes. We note a relationship, not generally appreciated, between the distortion of the near [PbI{sub 6}]{sup 4-} octahedrons and the polytype. We suggest that the significance of vacancies has only recently been appreciated. We suggest that small discrepancies in structure determination are probably due to different distributions of vacancies and that there are, in practice, very many structures for macroscopic or even mesoscopic samples of a given polytype when vacancies are considered. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  18. Chloride, bromide and iodide scintillators with europium

    Energy Technology Data Exchange (ETDEWEB)

    Zhuravleva, Mariya; Yang, Kan

    2016-09-27

    A halide scintillator material is disclosed where the halide may comprise chloride, bromide or iodide. The material is single-crystalline and has a composition of the general formula ABX.sub.3 where A is an alkali, B is an alkali earth and X is a halide which general composition was investigated. In particular, crystals of the formula ACa.sub.1-yEu.sub.yI.sub.3 where A=K, Rb and Cs were formed as well as crystals of the formula CsA.sub.1-yEu.sub.yX.sub.3 (where A=Ca, Sr, Ba, or a combination thereof and X=Cl, Br or I or a combination thereof) with divalent Europium doping where 0.ltoreq.y.ltoreq.1, and more particularly Eu doping has been studied at one to ten mol %. The disclosed scintillator materials are suitable for making scintillation detectors used in applications such as medical imaging and homeland security.

  19. Environmental monitoring of brominated flame retardants

    Science.gov (United States)

    Vagula, Mary C.; Kubeldis, Nathan; Nelatury, Charles F.

    2011-06-01

    Brominated flame retardants (BFRs) are synthetic organobromide compounds which inhibit ignition and combustion processes. Because of their immense ability to retard fire and save life and property, they have been extensively used in many products such as TVs, computers, foam, plastics etc. The five major classes of BFRs are tetrabromobisphenol-A (TBBPA), hexabromocyclododecane (HBCD), pentabromodiphenyl ether, octabromodiphenyl ether, and decabromodiphenyl ether. The last three are also commonly called PBDEs. BDE-85 and BDE-209 are the two prominent congeners of PBDEs and this study reports the adverse effects of these congeners in rodents. Exposure of rat sciatic nerves to 5 μg/mL and 20 μg/mL of BDE-85 and BDE-209 respectively lead to significant, concentration dependent reduction in nerve conduction function. Glucose absorption in the rat intestinal segments exposed to 5 μg/mL of BDE-85 and BDE-209 was significantly reduced for both the compounds tested. Lastly, mice when exposed to 0.25 mg/kg body weight for four days showed a disruption in oxidant and antioxidant equilibrium. The tissues namely liver and brain have shown increase in the levels of lipid hydroperoxides indicating oxidative stress. Moreover, all the protective enzymes namely superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase, and glutathione S transferase (GST) have shown tissue specific alterations indicating the induction of damaging oxidative stress and setting in of lipid peroxidation in exposed animals. The results indicate monitoring of PBDEs in the environment is essential because levels as low as 5 μg/mL and 0.25 mg/kg body weight were able to cause damage to the functions of rodents.

  20. The geochemistry of stable chlorine and bromine isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Eggenkamp, Hans [Onderzock and Beleving, Bussum (Netherlands)

    2014-11-01

    First book solely dedicated to the geochemistry of chlorine and bromine isotopes. Detailed description of analytical techniques, including their advantages and disadvantages. Indication of research fields where measurement of these isotopes is especially useful. This book provides detailed information on the history, analysis and applications of chlorine and bromine isotope geochemistry. Chlorine and bromine are geochemically unique as they prefer to exist as single charged negative ions. For this reason isotope fractionation reflects mostly processes that are not related to changes in the redox state and this fractionation is generally modest. The book will describe the processes that are most easily detected using these isotopes. Also isotope variations, and processes that cause them, measured in oxidised species such as perchlorates and in organic molecules will be described in this book.

  1. 40 CFR 180.519 - Bromide ion and residual bromine; tolerances for residues.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Bromide ion and residual bromine... Tolerances § 180.519 Bromide ion and residual bromine; tolerances for residues. (a) General. The food additives, bromide ion and residual bromine, may be present in water, potable in accordance with...

  2. Iodide kinetics and experimental I-131 therapy in a xenotransplanted human sodium-iodide symporter-transfected human follicular thyroid carcinoma cell line

    NARCIS (Netherlands)

    Smit, J.W.A.; Elst, van der J.P.; Karperien, M.; Que, I.; Stokkel, M.; Heide, van der D.; Romijn, J.A.

    2002-01-01

    Uptake of iodide is a prerequisite for radioiodide therapy in thyroid cancer. However, loss of iodide uptake is frequently observed in metastasized thyroid cancer, which may be explained by diminished expression of the human sodium-iodide symporter (hNIS). We studied whether transfection of hNIS int

  3. Evaluation of mercuric iodide ceramic semiconductor detectors

    Energy Technology Data Exchange (ETDEWEB)

    Schieber, M.; Zuck, A.; Braiman, M.; Nissenbaum, J. [Hebrew Univ., Jerusalem (Israel); Turchetta, R.; Dulinski, W.; Husson, D.; Riester, J.L. [LEPSI (ULP/IN2P3), Strasbourg (France)

    1998-02-01

    Mercuric iodide ceramic radiation detectors, which can act as nuclear particle counters, have been fabricated with single continuos electrical contacts and with linear strip contacts. They have been tested with different kinds of {gamma} and {beta} sources as well as in a high energy beam at CERN. The detectors were also successfully tested for radiation hardness with irradiation of 5*10{sup 14} neutrons/cm{sup 2}. The ratio of detected photons over the number of absorbed photons has been measured with {gamma} sources of different energies, and it ranges from 20% at 44 keV up to about 30% at 660 keV. An absolute efficiency of 70% has been measured for a 350 {mu}m thick detector for {beta} particles emitted by a {sup 90}Sr source. Charge collection efficiency, defined as the amount of charge induced on the electrodes by a mminimum ionizing particle (MIP) traversing the detector, has been measured in two samples. The average collected charge fits well with a linear curve with slope of 35 electrons/(kV/cm) per 100 {mu}m. This result is well described by a dynamic device simulation, where the free carrier mean lifetime is used as a free parameter, adjusted to a value of 1.5 ns, i.e. about 1/100 of the corresponding lifetime in single crystal HgI{sub 2} detectors. The response to MIP has also been studied with a high energy (100 GeV) muon beam in CERN. A preliminary beam profile is presented while a more detailed analysis is still in progress and will be presented elsewhere. These results together with the low cost of the material make ceramic HgI{sub 2} detectors excellent candidates for large area particle tracking and imaging applications, even in a radiation harsh environment. (orig.). 14 refs.

  4. Global sea-to-air flux climatology for bromoform, dibromomethane and methyl iodide

    Directory of Open Access Journals (Sweden)

    F. Ziska

    2013-02-01

    Full Text Available Volatile halogenated organic compounds containing bromine and iodine, which are naturally produced in the ocean, are involved in ozone depletion in both the troposphere and stratosphere. Three prominent compounds transporting large amounts of marine halogens into the atmosphere are bromoform (CHBr3, dibromomethane (CH2Br2 and methyl iodide (CH3I. The input of marine halogens to the stratosphere is based on observations and modeling studies using low resolution oceanic emission scenarios derived from top down approaches. In order to improve emission inventory estimates, we calculate data-based high resolution global sea-to-air flux estimates of these compounds from surface observations within the HalOcAt database (https://halocat.geomar.de/. Global maps of marine and atmospheric surface concentrations are derived from the data which are divided into coastal, shelf and open ocean regions. Considering physical and biogeochemical characteristics of ocean and atmosphere, the open ocean water and atmosphere data are classified into 21 regions. The available data are interpolated onto a 1° × 1° grid while missing grid values are interpolated with latitudinal and longitudinal dependent regression techniques reflecting the compounds' distributions. With the generated surface concentration climatologies for the ocean and atmosphere, global concentration gradients and sea-to-air fluxes are calculated. Based on these calculations we estimate a total global flux of 1.5/2.5 Gmol Br yr−1 for CHBr3, 0.78/0.98 Gmol Br yr−1 for CH2Br2 and 1.24/1.45 Gmol I yr−1 for CH3I (Robust Fit/Ordinary Least Square regression technique. Contrary to recent studies, negative fluxes occur in each sea-to-air flux climatology, mainly in the Arctic and Antarctic region. "Hot spots" for global

  5. Global sea-to-air flux climatology for bromoform, dibromomethane and methyl iodide

    Directory of Open Access Journals (Sweden)

    F. Ziska

    2013-09-01

    Full Text Available Volatile halogenated organic compounds containing bromine and iodine, which are naturally produced in the ocean, are involved in ozone depletion in both the troposphere and stratosphere. Three prominent compounds transporting large amounts of marine halogens into the atmosphere are bromoform (CHBr3, dibromomethane (CH2Br2 and methyl iodide (CH3I. The input of marine halogens to the stratosphere has been estimated from observations and modelling studies using low-resolution oceanic emission scenarios derived from top-down approaches. In order to improve emission inventory estimates, we calculate data-based high resolution global sea-to-air flux estimates of these compounds from surface observations within the HalOcAt (Halocarbons in the Ocean and Atmosphere database (https://halocat.geomar.de/. Global maps of marine and atmospheric surface concentrations are derived from the data which are divided into coastal, shelf and open ocean regions. Considering physical and biogeochemical characteristics of ocean and atmosphere, the open ocean water and atmosphere data are classified into 21 regions. The available data are interpolated onto a 1°×1° grid while missing grid values are interpolated with latitudinal and longitudinal dependent regression techniques reflecting the compounds' distributions. With the generated surface concentration climatologies for the ocean and atmosphere, global sea-to-air concentration gradients and sea-to-air fluxes are calculated. Based on these calculations we estimate a total global flux of 1.5/2.5 Gmol Br yr−1 for CHBr3, 0.78/0.98 Gmol Br yr−1 for CH2Br2 and 1.24/1.45 Gmol Br yr−1 for CH3I (robust fit/ordinary least squares regression techniques. Contrary to recent studies, negative fluxes occur in each sea-to-air flux climatology, mainly in the Arctic and Antarctic regions. "Hot spots" for global polybromomethane emissions are located in the equatorial region, whereas methyl iodide emissions are enhanced in the

  6. Methyl Iodide Formation Under Postulated Nuclear Reactor Accident Conditions

    International Nuclear Information System (INIS)

    The formation of methyl iodide under conditions of postulated nuclear reactor accidents is discussed. Although thermodynamic calculations indicate the equilibrium methyl iodide concentrations would be quite low, calculations based on a simple kinetic scheme involving reaction between small hydrocarbon species and iodine indicate that concentrations higher than equilibrium can occur during the course of the reaction. Such calculations were performed over a wide range of initial species concentrations and a range of temperatures representative of some reactor accident situations. These calculations suggest that little methyl iodide would be expected within the core volume where temperatures are maximum. As the gas leaves the core volume and expands into the plenum region, it cools and the concentration of methyl iodide increases. At the intermediate temperatures which might characterize this region, the formation of methyl iodide from thermally induced reactions could reach its maximum rate. The gas continues to cool, however, and it is probable that by the time it leaves the plenum region it has cooled to the point where thermally induced reactions may be of little importance. Although the thermally induced reactions will become slower as the gas expands and cools, the radiation-induced reactions will not be slowed to the same extent. The gases leaving the core carry fission products and hence a radiation source is available to initiate reaction by a temperature-independent process. An investigation of the radiation chemical formation and decomposition of methyl iodide in the presence of steam suggests that radiation-induced methyl iodide formation will generally be rapid under the postulated accident situations. Thus, in the plenum region where thermal reactions have become slow, the radiation-induced reaction can still proceed and may well become the dominant factor. The same situation probably pertains as well to the containment region. (author)

  7. Development of crystals based in cesium iodide for application as radiation detectors

    International Nuclear Information System (INIS)

    Inorganic scintillators with fast luminescence decay time, high density and high light output have been the object of studies for application in nuclear physics, high energy physics, nuclear tomography and other fields of science and engineering. Scintillation crystals based on cesium iodide (CsI) are matters with relatively low higroscopy, high atomic number, easy handling and low cost, characteristics that favor their use as radiation detectors. In this work, the growth of pure CsI crystals, CsI:Br and CsI:Pb, using the Bridgman technique, is described. The concentration of the bromine doping element (Br) was studied in the range of 1,5x10-1 M to 10-2 M and the lead (Pb) in the range of 10-2 M to 5x10-4 M. To evaluate the scintillators developed, systematic measurements were carried out for luminescence emission and luminescence decay time for gamma radiation, optical transmittance assays, Vickers micro-hardness assays, determination of the doping elements distribution along the grown crystals and analysis of crystals response to the gamma radiation in the energy range of 350 keV to 1330 keV and alpha particles from a 241Am source, with energy of 5.54 MeV. It was obtained 13 ns to 19 ns for luminescence decay time for CsI:Br and CsI:Pb crystals. These results were very promising. The results obtained for micro-hardness showed a significant increase in function of the doping elements concentration, when compared to the pure CsI crystal, increasing consequently the mechanical resistance of the grown crystals. The validity of using these crystals as radiation sensors may be seen from the results of their response to gamma radiation and alpha particles. (author)

  8. Discovery of zinc, selenium, bromine, and neodymium isotopes

    International Nuclear Information System (INIS)

    Currently, thirty-two zinc, thirty-two selenium, twenty-nine bromine, and thirty-one neodymium isotopes have been observed and the discovery of these isotopes is described here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.

  9. Thymol bromination: a comparison between enzymatic and chemical catalysis

    NARCIS (Netherlands)

    F. Sabuzi; E. Churakova; P. Galloni; R. Wever; F. Hollmann; B. Floris; V. Conte

    2015-01-01

    The catalytic activity of the vanadium-dependent bromoperoxidase isolated from the brown alga Ascophyllum nodosum is compared with the activity of a cheap, commercially available V-catalyst precursor in the bromination of thymol. Organic solvents have been avoided to make the system appealing from a

  10. Bromine provides new weapons to combat mercury emissions

    Energy Technology Data Exchange (ETDEWEB)

    Hardtke, W. [Albermarle Europe (Germany)

    2011-04-15

    Brominated powdered activated carbon has been demonstrated to capture over 90% of mercury emissions from coal fired plants, operating at high temperatures and capturing the metal in concrete-friendly, non-leaching forms to help tackle a rising global health threat. 6 refs., 5 figs.

  11. Brominated Dioxins: Little-Known New Health Hazards - A Review

    Directory of Open Access Journals (Sweden)

    Piskorska-Pliszczyńska Jadwiga

    2014-10-01

    Full Text Available This article reviews the present state of the science concerning the polybrominated dibenzo-p-dioxins (PBDDs and dibenzofurans (PBDFs. Everywhere in the world people are exposed to anthropogenic origin chemicals. Some of them are long-lived organic compounds, which persist over the years in the environment. Persistent organic pollutants, such as organohalogen compounds, accumulate in environmental and biological compartments and have adverse effects on the health of humans and animals. Little is known about the brominated and mixed chloro/bromo dioxin and furans. Existing literature suggests that brominated dioxins and furans have similar toxicity profiles to their chlorinated analogues. The exposure data are extremely limited, showing a major data gap in estimating the potential environmental and health risk of these chemicals. The rapid increase in the use of brominated flame retardants (the main source of these pollutants has raised the level of concern over environmental and health damage from brominated dioxins and furans. It is likely that human as well as wildlife exposure to these contaminants will increase with their greater use. The findings reported here present strong evidence of the PBDDs and PBDFs as an emerging new class of contaminants.

  12. Discovery of Zinc, Selenium, Bromine, and Neodymium Isotopes

    OpenAIRE

    J.L. Gross; Claes, J.; Kathawa, J.; Thoennessen, M

    2010-01-01

    Currently, thirty-two zinc, thirty-two selenium, twenty-nine bromine and thirty-one neodymium isotopes have been observed and the discovery of these isotopes is discussed here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented.

  13. Airborne measurements of organic bromine compounds in the Pacific tropical tropopause layer.

    Science.gov (United States)

    Navarro, Maria A; Atlas, Elliot L; Saiz-Lopez, Alfonso; Rodriguez-Lloveras, Xavier; Kinnison, Douglas E; Lamarque, Jean-Francois; Tilmes, Simone; Filus, Michal; Harris, Neil R P; Meneguz, Elena; Ashfold, Matthew J; Manning, Alistair J; Cuevas, Carlos A; Schauffler, Sue M; Donets, Valeria

    2015-11-10

    Very short-lived brominated substances (VSLBr) are an important source of stratospheric bromine, an effective ozone destruction catalyst. However, the accurate estimation of the organic and inorganic partitioning of bromine and the input to the stratosphere remains uncertain. Here, we report near-tropopause measurements of organic brominated substances found over the tropical Pacific during the NASA Airborne Tropical Tropopause Experiment campaigns. We combine aircraft observations and a chemistry-climate model to quantify the total bromine loading injected to the stratosphere. Surprisingly, despite differences in vertical transport between the Eastern and Western Pacific, VSLBr (organic + inorganic) contribute approximately similar amounts of bromine [∼6 (4-9) parts per trillion] [corrected] to the stratospheric input at the tropical tropopause. These levels of bromine cause substantial ozone depletion in the lower stratosphere, and any increases in future abundances (e.g., as a result of aquaculture) will lead to larger depletions. PMID:26504212

  14. Bismuth tri-iodide radiation detector development

    Science.gov (United States)

    Gokhale, Sasmit S.

    Bismuth tri-iodide is an attractive material for room temperature radiation detection. BiI3 demonstrates a number of properties that are apt for semiconductor radiation detection, especially gamma ray spectroscopy. The high atomic number (ZBi = 83 and ZI = 53) and the relatively high density (5.78 g/cm3) cause the material to have good photon stopping power, while the large band-gap (1.67 eV ) allows it to function as a room temperature radiation detector without any cooling mechanism. This work presents the fabrication and characterization of BiI3 radiation detectors. For the purpose of this research detectors were fabricated by cutting BiI3 crystal boules, followed by mechanical and chemical surface treatments. Detectors with various electrode geometries enabling single polarity charge sensing were fabricated. The electrical characteristics and the radiation response of the detectors were measured. The radiation response measurement was performed at room temperature using a 241Am alpha particle source and a 241Am sealed gamma-ray source. The spectral resolutions of the detectors varied from 2.09% - 6.1% for 59.5 keV gamma-rays and between 26% - 40% for 5.48 MeV alpha particles. Charge carrier properties such as the electron and hole mobility and lifetime were also estimated. The electron mobility for an ultrapure BiI 3 detector was estimated to be approximately 433 cm 2/Vs while that for antimony doped BiI3 was estimated to be around 956 cm2/Vs and the mobility-lifetime product for electrons was estimated to be around 5.44 x 10-4 cm 2/V. Detector simulation was performed using the Monte Carlo simulation code MCNP5. A Matlab script which incorporates charge carrier trapping and statistical variation was written to generate a gamma-ray spectrum from the simulated energy deposition spectra. Measured and simulated spectra were compared to extract the charge carrier mobility-lifetime products, which for electrons and holes were estimated to be 5 x 10-3 cm2/V and 1.3 x

  15. Macrosegregation during Plane Front Solidification of Cesium Iodide wt Percent Thallium Iodide Alloy

    Science.gov (United States)

    Sidawi, Ibrahim M. S.

    Macrosegregation produced during directional solidification of CsI-1 wt% TlI by vertical Bridgman technique has been examined in crucibles of varying diameter, from 0.5 to 2.0 cm. Phase diagram and temperature dependence of the thermal conductivity have been determined. The experimentally observed liquid-solid interface shape and the fluid flow behavior have been compared with that computed from the commercially available code FIDAP. Thallium iodide content of the alloy was observed to increase along the length of the directionally solidified specimens, resulting in continuously decreasing light output. The experimentally observed solutal distribution agrees with predictions from the boundary layer model of Favier. The observed macrosegregation behavior suggests that there is a significant convection in the melt even in the smallest crucible diameter of 0.5 cm.

  16. Bromine measurements in ozone depleted air over the Arctic Ocean

    Directory of Open Access Journals (Sweden)

    J. A. Neuman

    2010-07-01

    Full Text Available In situ measurements of ozone, photochemically active bromine compounds, and other trace gases over the Arctic Ocean in April 2008 are used to examine the chemistry and geographical extent of ozone depletion in the arctic marine boundary layer (MBL. Data were obtained from the NOAA WP-3D aircraft during the Aerosol, Radiation, and Cloud Processes affecting Arctic Climate (ARCPAC study and the NASA DC-8 aircraft during the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS study. Fast (1 s and sensitive (detection limits at the low pptv level measurements of BrCl and BrO were obtained from three different chemical ionization mass spectrometer (CIMS instruments, and soluble bromide was measured with a mist chamber. The CIMS instruments also detected Br2. Subsequent laboratory studies showed that HOBr rapidly converts to Br2 on the Teflon instrument inlets. This detected Br2 is identified as active bromine and represents a lower limit of the sum HOBr + Br2. The measured active bromine is shown to likely be HOBr during daytime flights in the arctic. In the MBL over the Arctic Ocean, soluble bromide and active bromine were consistently elevated and ozone was depleted. Ozone depletion and active bromine enhancement were confined to the MBL that was capped by a temperature inversion at 200–500 m altitude. In ozone-depleted air, BrO rarely exceeded 10 pptv and was always substantially lower than soluble bromide that was as high as 40 pptv. BrCl was rarely enhanced above the 2 pptv detection limit, either in the MBL, over Alaska, or in the arctic free troposphere.

  17. Phase 1 Methyl Iodide Deep-Bed Adsorption Tests

    Energy Technology Data Exchange (ETDEWEB)

    Nick Soelberg; Tony Watson

    2014-08-01

    Nuclear fission results in the production of fission products (FPs) and activation products including iodine-129, which could evolve into used fuel reprocessing facility off-gas systems, and could require off-gas control to limit air emissions to levels within acceptable emission limits. Research, demonstrations, and some reprocessing plant experience have indicated that diatomic iodine can be captured with efficiencies high enough to meet regulatory requirements. Research on the capture of organic iodides has also been performed, but to a lesser extent [Jubin 2012b]. Several questions remain open regarding the capture of iodine bound in organic compounds. Deep-bed methyl iodide adsorption testing has progressed according to a multi-laboratory methyl iodide adsorption test plan. This report summarizes the first phase of methyl iodide adsorption work performed according to this test plan using the deep-bed iodine adsorption test system at the Idaho National Laboratory (INL), performed during Fiscal Year (FY) 2013 and early FY-2014. Testing has been performed to address questions posed in the test plan, and followed the testing outline in the test plan. Tests established detection limits, developed procedures for sample analysis with minimal analytical interferences, and confirmed earlier results that show that the methyl iodide reacts when in contact with the AgZ sorbent, and not significantly in the gas flow upstream of the sorbent. The reaction(s) enable separation of the iodine from the organic moiety, so that the iodine can chemisorb onto the sorbent. The organic moiety can form other compounds, some of which are organic compounds that are detected and can be tentatively identified using GC-FID and GCMS. Test results also show that other gas constituents (NOx and/or H2O) can affect the methyl iodide reactions. With NOx and H2O present in the gas stream, the majority of uncaptured iodine exiting iodine-laden sorbent beds is in the form of I2 or HI, species that

  18. Standard free energy of formation of iron iodide

    Science.gov (United States)

    Khandkar, A.; Tare, V. B.; Wagner, J. B., Jr.

    1983-01-01

    An experiment is reported where silver iodide is used to determine the standard free energy of formation of iron iodide. By using silver iodide as a solid electrolyte, a galvanic cell, Ag/AgI/Fe-FeI2, is formulated. The standard free energy of formation of AgI is known, and hence it is possible to estimate the standard free energy of formation of FeI2 by measuring the open-circuit emf of the above cell as a function of temperature. The free standard energy of formation of FeI2 determined by this method is -38784 + 24.165T cal/mol. It is estimated that the maximum error associated with this method is plus or minus 2500 cal/mol.

  19. A novel peculiar mutation in the sodium/iodide symporter gene in spanish siblings with iodide transport defect.

    Science.gov (United States)

    Kosugi, Shinji; Okamoto, Hiroomi; Tamada, Aiko; Sanchez-Franco, F

    2002-08-01

    Previously, we reported two Spanish siblings with congenital hypothyroidism due to total failure of iodide transport. These were the only cases reported to date who received long-term iodide treatment over 10 yr. We examined the sodium/iodide symporter (NIS) gene of these patients. A large deletion was observed by long and accurate PCR using primers derived from introns 2 and 7 of the NIS gene. PCR-direct sequencing revealed a deletion of 6192 bases spanning from exon 3 to intron 7 and an inverted insertion of a 431-base fragment spanning from exon 5 to intron 5 of the NIS gene. The patients were homozygous for the mutation, and their mother was heterozygous. In the mutant, deletion of exons 3-7 was suggested by analysis using programs to predict exon/intron organization, resulting in an in-frame 182-amino acid deletion from Met(142) in the fourth transmembrane domain to Gln(323) in the fourth exoplasmic loop. The mutant showed no iodide uptake activity when transfected into COS-7 cells, confirming that the mutation was the direct cause of the iodide transport defect in these patients. Further, the mutant NIS protein was synthesized, but not properly expressed, on the cell surface, but was mostly accumulated in the cytoplasm, suggesting impaired targeting to the plasma membrane. PMID:12161518

  20. Enhanced Olefin Cross Metathesis Reactions: The Copper Iodide Effect

    Science.gov (United States)

    Voigtritter, Karl; Ghorai, Subir

    2011-01-01

    Copper iodide has been shown to be an effective co-catalyst for the olefin cross metathesis reaction. In particular, it has both a catalyst stabilizing effect due to iodide ion, as well as copper(I)-based phosphine-scavenging properties that apply to use of the Grubbs-2 catalyst. A variety of Michael acceptors and olefinic partners can be cross-coupled under mild conditions in refluxing diethyl ether that avoid chlorinated solvents. This effect has also been applied to chemistry in water at room temperature using the new surfactant TPGS-750-M. PMID:21528868

  1. Mercuric iodide dosimeter response to high energy electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Loewinger, E.; Nissenbaum, J.; Schieber, M.M.

    1988-01-01

    Mercuric iodide solid state dosimeter response to high energy electron beams of up to 35 MeV is reported. High sensitivity of up to 1.5 V/cGy was observed with a 200 V external bias, as well as several mV/cGy, with no external bias for small volume (approx. 10 mm/sup 3/) detectors. The physical characteristics of the detector response are discussed, showing the feasibility of mercuric iodide as a reliable dosimeter for high energy electron beams.

  2. Occurrence of bromine in fluidised bed combustion of solid recovered fuel

    Energy Technology Data Exchange (ETDEWEB)

    Vainikka, P.

    2011-12-15

    Corrosive ash species are the single most important factor limiting the electric efficiency of steam boiler plants fired with waste or biomass. Chlorine has been found to have a central role in the chemistry involved as it reduces the melting temperature of ash, forms corrosive vapour and gas species in the furnace and halogenated deposits on boiler heat transfer surfaces. In this context chlorine has been extensively researched. At the time of writing this thesis there was hardly any published data available on the occurrence of bromine (Br) in the aforementioned context. The objective of this work was to review the occurrence of bromine in solid fuels and characterise the behaviour of bromine in full-scale fluidised bed combustion. The review on the occurrence of bromine in solid fuels revealed that in anthropogenic wastes bromine is mainly found in connection to flame retarded substances. Several weight percentages of bromine can be found in plastics treated with brominated flame retardants (BFRs). Bromine is typically found some 100-200 mg kg-1 in mixed municipal solid wastes (MSW). Bromine may be enriched in fuels with high share of plastics, such as solid recovered fuel (SRF) or refuse derived fuel (RDF). Up to 2000 mg kg-1 was found as a monthly average in SRF, typical levels being 20-200 mg kg-1. Wastewater sludge from paper mills may contain bromine 20-100 mg kg-1 due the use of bromine based biocides. In other fuels bromine may be found in significant amounts in marine influenced coal deposits and peat as well as in biomass treated with brominated pesticides. In the experimental part SRF, spruce bark and wastewater sludge from a paper mill were co-fired in a full- scale bubbling fluidised bed (BFB) boiler, and the collected fuels, aerosols and waterwall deposits were analysed with the focus on the fate of bromine. Bromine was mainly found to form water soluble high vapour pressure alkali metal halides in the furnace - in the form of KBr(g) and NaBr(g) as

  3. Uptake of Iodide From Water in Atlantic Halibut Larvae (Hippoglossus Hippoglossus L.)

    DEFF Research Database (Denmark)

    Moren, Mari; Sloth, Jens Jørgen; Hamre, Kristin

    2008-01-01

    relative low levels of iodide (0-22 nM) and except for samples from one site; the levels of iodide and iodate were in agreement with previously published data. The uptake of iodide from seawater was measured by incubating Atlantic halibut larvae in water with a constant level of radioactive iodide (I-125...... is whether Atlantic halibut larvae are capable of absorbing iodide from the water and if so, can the seawater sustain the iodine requirement during larval development and metamorphosis. Levels of iodide and iodate in seawater samples from four different rearing facilities were analysed. All samples contained...... concentration of iodide in the water. The highest level of iodide used was 2000 nM,100 times higher than what was measured in the seawater samples. The uptake curves did not seem to reach equilibrium. This may be due to a constant nonspecific uptake or that the equilibrium level is higher than 2000 n...

  4. The electrosorption of tetraalkylammonium ions on silver iodide

    NARCIS (Netherlands)

    Keizer, de A.

    1981-01-01

    The object of the present investigations was to study the ef fect of the adsorption of charged organic ions on electrically charged, solid-liquid interfaces. To that end, symmetrical quater nary ammonium ions were adsorbed on a silver iodide-electrolyte interface at various surface charges. The elec

  5. Radiation-hard polycrystalline mercuric iodide semiconductor particle counters

    Energy Technology Data Exchange (ETDEWEB)

    Schieber, M. [Hebrew Univ., Jerusalem (Israel)]|[Sandia National Laboratories, Livermore Ca 94556 (United States); Zuck, A.; Melekhov, L.; Nissenbaum, J. [Hebrew Univ., Jerusalem (Israel); Turchetta, R.; Dulinski, W.; Husson, D.; Riester, J.L. [LEPSI (ULP/IN2P3), Strasbourg (France)

    1998-06-01

    Mercuric iodide polycrystalline radiation detectors, which can act as nuclear particle counters and for large area imaging devices, have been fabricated using three different methods. Response to X- and gamma rays, beta particles and to 100GeV muons, as well as radiation hardness results are briefly described. (orig.) 8 refs.

  6. Iodide volatility under condition relevant to PWR steam generator faults

    International Nuclear Information System (INIS)

    The evaluation of iodine volatility during steam generator tube rupture (SGTR) is hampered by three factors: (i) lack of suitable plant data under fault conditions, (ii) lack of experimental data (mainly due to the difficulty of performing experiments under the conditions required) and (iii) uncertainty in theoretical methods to extrapolate experimental data to the required conditions. This report summarises methods of estimating the volatility of hydrogen iodide and iodide salts at the required conditions of temperature and pressure. A thermodynamic method has been used to estimate HI volatility and the density correlation method for iodide salt volatility. It is assumed throughout that it is more conservative to predict higher volatility. Consideration is given to two explanations of experiments carried out at Oak Ridge National Laboratory (ORNL) on the influence of boric acid concentration and pH on the volatility of radioiodine ostensibly under SGTR conditions: (i) the results have been interpreted in terms of reactions involving volatility of iodide salt/ion-pairs and complexation by boric acid in the gas phase and (ii) the possibility is explored that the observed results are due to the influence of oxidation leading to the formation of much more volatile iodine species. (author)

  7. FY-2015 Methyl Iodide Deep-Bed Adsorption Test Report

    Energy Technology Data Exchange (ETDEWEB)

    Soelberg, Nicholas Ray [Idaho National Lab. (INL), Idaho Falls, ID (United States); Watson, Tony Leroy [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2015-09-30

    Nuclear fission produces fission and activation products, including iodine-129, which could evolve into used fuel reprocessing facility off-gas systems, and could require off-gas control to limit air emissions to levels within acceptable emission limits. Deep-bed methyl iodide adsorption testing has continued in Fiscal Year 2015 according to a multi-laboratory methyl iodide adsorption test plan. Updates to the deep-bed test system have also been performed to enable the inclusion of evaporated HNO3 and increased NO2 concentrations in future tests. This report summarizes the result of those activities. Test results showed that iodine adsorption from gaseous methyl iodide using reduced silver zeolite (AgZ) resulted in initial iodine decontamination factors (DFs, ratios of uncontrolled and controlled total iodine levels) under 1,000 for the conditions of the long-duration test performed this year (45 ppm CH3I, 1,000 ppm each NO and NO2, very low H2O levels [3 ppm] in balance air). The mass transfer zone depth exceeded the cumulative 5-inch depth of 4 bed segments, which is deeper than the 2-4 inch depth estimated for the mass transfer zone for adsorbing I2 using AgZ in prior deep-bed tests. The maximum iodine adsorption capacity for the AgZ under the conditions of this test was 6.2% (6.2 g adsorbed I per 100 g sorbent). The maximum Ag utilization was 51%. Additional deep-bed testing and analyses are recommended to (a) expand the data base for methyl iodide adsorption and (b) provide more data for evaluating organic iodide reactions and reaction byproducts for different potential adsorption conditions.

  8. FY-2015 Methyl Iodide Deep-Bed Adsorption Test Report

    International Nuclear Information System (INIS)

    Nuclear fission produces fission and activation products, including iodine-129, which could evolve into used fuel reprocessing facility off-gas systems, and could require off-gas control to limit air emissions to levels within acceptable emission limits. Deep-bed methyl iodide adsorption testing has continued in Fiscal Year 2015 according to a multi-laboratory methyl iodide adsorption test plan. Updates to the deep-bed test system have also been performed to enable the inclusion of evaporated HNO3 and increased NO2 concentrations in future tests. This report summarizes the result of those activities. Test results showed that iodine adsorption from gaseous methyl iodide using reduced silver zeolite (AgZ) resulted in initial iodine decontamination factors (DFs, ratios of uncontrolled and controlled total iodine levels) under 1,000 for the conditions of the long-duration test performed this year (45 ppm CH3I, 1,000 ppm each NO and NO2, very low H2O levels [3 ppm] in balance air). The mass transfer zone depth exceeded the cumulative 5-inch depth of 4 bed segments, which is deeper than the 2-4 inch depth estimated for the mass transfer zone for adsorbing I2 using AgZ in prior deep-bed tests. The maximum iodine adsorption capacity for the AgZ under the conditions of this test was 6.2% (6.2 g adsorbed I per 100 g sorbent). The maximum Ag utilization was 51%. Additional deep-bed testing and analyses are recommended to (a) expand the data base for methyl iodide adsorption and (b) provide more data for evaluating organic iodide reactions and reaction byproducts for different potential adsorption conditions.

  9. Bromination of hydrocarbons with CBr4, initiated by light-emitting diode irradiation

    Directory of Open Access Journals (Sweden)

    Yuta Nishina

    2013-08-01

    Full Text Available The bromination of hydrocarbons with CBr4 as a bromine source, induced by light-emitting diode (LED irradiation, has been developed. Monobromides were synthesized with high efficiency without the need for any additives, catalysts, heating, or inert conditions. Action and absorption spectra suggest that CBr4 absorbs light to give active species for the bromination. The generation of CHBr3 was confirmed by NMR spectroscopy and GC–MS spectrometry analysis, indicating that the present bromination involves the homolytic cleavage of a C–Br bond in CBr4 followed by radical abstraction of a hydrogen atom from a hydrocarbon.

  10. High selectively oxidative bromination of toluene derivatives by the H2O2-HBr system

    Institute of Scientific and Technical Information of China (English)

    Jie Ju; Yu Jin Li; Jian Rong Gao; Jian Hong Jia; Liang Han; Wei Jian Sheng; Yi Xia Jia

    2011-01-01

    An aqueous solution of hydrogen peroxide and hydrogen bromide illuminated by a 60 W incandescent light bulb serves as a source of bromine radicals. Various substituted toluenes (NO2,Cl, Br, H, CH3) were high selectively brominated at the benzyl position for monobromination in CH2C12 at ice water with catalyst free. This simple but effective bromination of toluene derivatives with an aqueous H2O2-HBr system is characterized with the use of inexpensive reagents and a lower impact on the environment, which make it a good alternative to the existing bromination methods.

  11. Elemental Bromine Production by TiO2 Photocatalysis and/or Ozonation.

    Science.gov (United States)

    Parrino, Francesco; Camera Roda, Giovanni; Loddo, Vittorio; Palmisano, Leonardo

    2016-08-22

    Significant production of elemental bromine (Br2 ) was observed for the first time when treating bromide containing solutions at acidic pH, with TiO2 photocatalyst, ozone, or a combination thereof. Br2 selectivities up to approximately 85 % were obtained and the corresponding bromine mass balance values satisfied. The process is general and may be applied at a laboratory scale for green bromination reactions, or industrially as a cheap, safe, and environmentally sustainable alternative to the currently applied bromine production methods.

  12. Specific heat of pristine and brominated graphite fibers, composites and HOPG. [Highly Oriented Pyrolytic Graphite

    Science.gov (United States)

    Hung, Ching-Chen; Maciag, Carolyn

    1987-01-01

    Differential scanning calorimetry was used to obtain specific heat values of pristine and brominated P-100 graphite fibers and brominated P-100/epoxy composite as well as pristine and brominated highly oriented pyrolytic graphite (HOPG) for comparison. Based on the experimental results obtained, specific heat values are calculated for several different temperatures, with a standard deviation estimated at 1.4 percent of the average values. The data presented here are useful in designing heat transfer devices (such as airplane de-icing heaters) from bromine fibers.

  13. Thermodynamic analysis of production of high purity titanium by thermal decomposition of titanium iodide

    Institute of Scientific and Technical Information of China (English)

    CHEN Xiao-hu; WANG Hua; LIU Yi-min; FANG Min

    2009-01-01

    High purity titanium was prepared by thermal decomposition of titanium iodide. The feasible synthetic route and optimum decompositon temperaure were obtained by thermodynamic analysis in the process of thermal decomposition of titanium iodide and nucleation growth theory. The temperature for the formation of titanium iodide is in the range of 800-900 K, at which a large amount of titanium iodide vapour can be obtained. The decomposition temperature of titanium iodide is in the range of 1 300-1 500 K, at which a favourable decomposition rate can be achieved. The experiment results show that the purity of the produced titanium is more than 99.995%.

  14. A novel mutation in the sodium/iodide symporter gene in the largest family with iodide transport defect.

    Science.gov (United States)

    Kosugi, S; Bhayana, S; Dean, H J

    1999-09-01

    We previously reported nine children with an autosomally recessive form of congenital hypothyroidism due to an iodide transport defect in a large Hutterite family with extensive consanguinity living in central Canada. Since the original report, we have diagnosed congenital hypothyroidism by newborn TSH screening in 9 additional children from the family. We performed direct sequencing of the PCR products of each NIS (sodium/iodide symporter) gene exon with flanking introns amplified from genomic DNA extracted from peripheral blood cells of the patients. We identified a novel NIS gene mutation, G395R (Gly395-->Arg; GGA-->AGA), in 10 patients examined in the present study. All of the parents tested were heterozygous for the mutation, suggesting that the patients were homozygous. The mutation was located in the 10th transmembrane helix. Expression experiments by transfection of the mutant NIS complimentary DNA into COS-7 cells showed no perchlorate-sensitive iodide uptake, confirming that the mutation is the direct cause of the iodide transport defect in these patients. A patient who showed an intermediate saliva/serum technetium ratio (14.0; normal, > or = 20) and was considered to have a partial or less severe defect in the previous report (IX-24) did not have a NIS gene mutation. It is now possible to use gene diagnostics of this unique NIS mutation to identify patients with congenital hypothyroidism due to an iodide transport defect in this family and to determine the carrier state of potential parents for genetic counseling and arranging rapid and early diagnosis of their infants. PMID:10487695

  15. Measurement-based modeling of bromine chemistry in the boundary layer: 1. Bromine chemistry at the Dead Sea

    OpenAIRE

    Tas, E.; Peleg, M.; D. U. Pedersen; Matveev, V; Pour Biazar, A.; Luria, M.

    2006-01-01

    International audience The Dead Sea is an excellent natural laboratory for the investigation of Reactive Bromine Species (RBS) chemistry, due to the high RBS levels observed in this area, combined with anthropogenic air pollutants up to several ppb. The present study investigated the basic chemical mechanism of RBS at the Dead Sea using a numerical one-dimensional chemical model. Simulations were based on data obtained from comprehensive measurements performed at sites along the Dead Sea. ...

  16. Inorganic bromine in the marine boundary layer: a critical review

    Directory of Open Access Journals (Sweden)

    R. Sander

    2003-06-01

    Full Text Available The cycling of inorganic bromine in the marine boundary layer (mbl has received increased attention in recent years. Bromide, a constituent of sea water, is injected into the atmosphere in association with sea-salt aerosol by breaking waves on the ocean surface. Measurements reveal that supermicrometer sea-salt aerosol is depleted in bromine by about 50% relative to conservative tracers, whereas marine submicrometer aerosol is often enriched in bromine. Model calculations, laboratory studies, and field observations strongly suggest that these depletions reflect the chemical transformation of particulate bromide to reactive inorganic gases that influence the processing of ozone and other important constituents of marine air. However, currently available techniques cannot reliably quantify many chem{Br}-containing compounds at ambient concentrations and, consequently, our understanding of inorganic Br cycling over the oceans and its global significance are uncertain. To provide a more coherent framework for future research, we have reviewed measurements in marine aerosol, the gas phase, and in rain. We also summarize sources and sinks, as well as model and laboratory studies of chemical transformations. The focus is on inorganic bromine over the open oceans, excluding the polar regions. The generation of sea-salt aerosol at the ocean surface is the major tropospheric source producing about 6.2 Tg/a of bromide. The transport of  Br from continents (as mineral aerosol, and as products from biomass-burning and fossil-fuel combustion can be of local importance. Transport of degradation products of long-lived Br-containing compounds from the stratosphere and other sources contribute lesser amounts. Available evidence suggests that, following aerosol acidification, sea-salt bromide reacts to form Br2 and BrCl that volatilize to the gas phase and photolyze in daylight to produce atomic Br and Cl. Subsequent transformations can destroy

  17. Defective organification of iodide causing congenital goitrous hypothyroidism.

    Science.gov (United States)

    Ishikawa, N; Eguchi, K; Ohmori, T; Momotani, N; Nagayama, Y; Hosoya, T; Oguchi, H; Mimura, T; Kimura, S; Nagataki, S; Ito, K

    1996-01-01

    A 26-yr-old Japanese woman with congenital goitrous hypo-thyroidism and sensorineural deafness underwent a thyroidectomy. Examination of the thyroid gland revealed characteristic features of multinodular goiter. The T3 and T4 content in thyroglobulin (Tg) were 0.03 and 0.02 mol/mol Tg, respectively. Iodide incorporation into Tg, using slices of the thyroid tissue, revealed that iodide organification of thyroid tissue from our patient was markedly lower than that of normal controls. Then, guaiacol and iodide oxidation activities of thyroid peroxidase (TPO) in our patient's thyroid tissue were lower than those of normal controls (guaiacol assay: 1.92 vs. 30.0 +/- 5.7 mGU/mg protein; iodide assay: 1.1 vs. 6.6 +/- 2.8 mIU/mg protein). Lineweaver-Burk plot analysis of the oxidation rates of guaiacol and iodide indicated that this patient's TPO had a defect in the binding of guaiacol and iodide, but the coupling activity of the patient's TPO was not decreased compared with those of two normal thyroids. In this case and in control subjects, Nothern gel analysis of TPO messenger RNA from unstimulated and TSH-stimulated thyroid cells revealed a 3.2 kilobase species in the former and four distinct messenger RNA species of 4.0, 3.2, 2.1, and 1.7 kilobases in the latter. Western blot analysis of TPOs obtained from this patient and from control subjects identified the same 107 kDa protein, using antimicrosomal antibody-positive serum. We analyzed the coding sequence in the patient's TPO gene by using polymerase chain reaction technique. A single point mutation of G-->C at 1265 base pair was detected only in the TPO gene, but this point mutation does not alter the amino acid residue. It is possible that posttranslational modification such as abnormal glycosylation may occur in the TPO molecules. Furthermore, it is possible that there are differences in the tertiary structures of the TPO molecules between our patient and normal subjects. The above abnormalities of TPO molecules

  18. New insight into photo-bromination processes in saline surface waters: The case of salicylic acid

    International Nuclear Information System (INIS)

    It was shown, through a combination of field and laboratory observations, that salicylic acid can undergo photo-bromination reactions in sunlit saline surface waters. Laboratory-scale experiments revealed that the photochemical yields of 5-bromosalicylic acid and 3,5-dibromosalicylic acid from salicylic acid were always low (in the 4% range at most). However, this might be of concern since these compounds are potential inhibitors of the 20α-hydroxysteroid dehydrogenase enzyme, with potential implications in endocrine disruption processes. At least two mechanisms were involved simultaneously to account for the photo-generation of brominated substances. The first one might involve the formation of reactive brominated radical species (Br·, Br2·−) through hydroxyl radical mediated oxidation of bromide ions. These ions reacted more selectively than hydroxyl radicals with electron-rich organic pollutants such as salicylic acid. The second one might involve the formation of hypobromous acid, through a two electron oxidation of bromine ions by peroxynitrite. This reaction was catalyzed by nitrite, since these ions play a crucial role in the formation of nitric oxide upon photolysis. This nitric oxide further reacts with superoxide radical anions to yield peroxynitrite and by ammonium through the formation of N-bromoamines, probably due to the ability of N-bromoamines to promote the aromatic bromination of phenolic compounds. Field measurements revealed the presence of salicylic acid together with 5-bromosalicylic and 3,5-dibromosalicylic acid in a brackish coastal lagoon, thus confirming the environmental significance of the proposed photochemically induced bromination pathways. -- Highlights: ► Brominated derivatives of salicylic acid were detected in a brackish lagoon. ► A photochemical pathway was hypothesized to account for bromination of salicylic acid. ► Radical bromine species are partly responsible for the bromination process. ► Hypobromous acid might

  19. Synthesis and Structure of Bis(4-nitrobenzaldehyde thiosemicarbazone) Cadmium Iodide

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The title complex, bis(4-nitrobenzaldehyde thiosemicarbazone) cadmium iodide (C16H16CdI2N8O4S2) crystallizes in the triclinic system, space group P1 with a=9.632(2), b=11.227(2), c=14.031(3), α= 67.50(3), β= 86.99(3), γ= 66.64(3)°, V=1278.13, Z = 2, Dc = 2.117gcm-3, F(000) = 772, μ =3.472mm-1 MoKα radiation (λ=0.71073), R = 0.0443, wR= 0.1425 for 4529 observed reflections [I>2σ(I)] of 4731 independent reflections. The result shows that the structure contains CdL2I2 (where L = 4-nitrobenzaldehyde thiosemicarbazone) distorted tetrahedral units in which the two ligands are S-bonded as monodentate to cadmium ion; the two iodide ions are also coordinated to Cd(II).

  20. (1,2-Dicarba-closo-dodecaboranyltrimethylmethanaminium iodide

    Directory of Open Access Journals (Sweden)

    Jong-Dae Lee

    2011-08-01

    Full Text Available The title compound, [1-(CH33NCH2-1,2-C2B10H11]+·I− or C6H22B10N+·I−, was obtained by the reaction of (1,2-dicarba-closo-dodecaboranyldimethylmethanamine with methyl iodide. The asymmetric unit contains two iodide anions and two (o-carboranyltetramethylammonium cations. The bond lengths and angles in the carborane cage are within normal ranges, but the N—Cmethylene—Ccage angle is very large [120.2 (2°] because of repulsion between the carborane and tetramethylammonium units. In the crystal, ions are linked through C—H...I hydrogen bonds.

  1. Methyl iodide production in the ocean: Implications for climate change

    Science.gov (United States)

    Smythe-Wright, Denise; Boswell, Stephen M.; Breithaupt, Petra; Davidson, Russell D.; Dimmer, Claudia H.; Eiras Diaz, Ledicia B.

    2006-09-01

    Methyl iodide concentrations of up to 45 pmol L-1, which flux into the marine boundary layer, have been found in low latitude waters of the Atlantic and Indian oceans. These high concentrations correlate well with the abundance of Prochlorococcus, and we have confirmed the release of methyl iodide by this species in laboratory culture experiments. Extrapolating, we estimate the global ocean flux of iodine to the marine boundary layer from this single source to be 5.3 × 1011 g I yr-1, which is a large fraction of the previously estimated total global flux and the implications are far reaching. Climate prediction models suggest increases in sea surface temperature and changes in biogeographical provenances in response to global warming. Such changes are likely to increase the abundance of Prochlorococcus, and we estimate a concomitant ˜15% increase in the release of iodine species to the atmosphere. Potentially, this could help mitigate global warming.

  2. New applications for the zinc iodide-osmium tetroxide technique.

    OpenAIRE

    Dağdeviren, A; ALP, H.; Ors, U

    1994-01-01

    The zinc iodide-osmium tetroxide (ZIO) fixation/staining method was applied for neurocytological studies and also to examine several other tissue samples including epidermal Langerhans cells, blood and bone marrow cells and lymphoid tissue. Although precise specificity cannot be attributed to the staining reaction, interesting staining patterns for different cell types were observed by using one of the ZIO staining solutions. The significance of ZIO positivity is briefly discussed.

  3. Heterogeneous ice nucleation on silver-iodide-like surfaces

    OpenAIRE

    Fraux, Guillaume; Doye, Jonathan P. K.

    2014-01-01

    We attempt to simulate the heterogeneous nucleation of ice at model silver-iodide surfaces and find relatively facile ice nucleation and growth at the Ag+ termi nated basal face, but never see nucleation at the I- terminated basal face or the prism and normal faces. Water molecules strongly adsorb onto the Ag+ terminate d face to give a well-ordered hexagonal ice-like bilayer that then acts as a template for further ice growth.

  4. Lead iodide perovskite light-emitting field-effect transistor

    OpenAIRE

    Chin, Xin Yu; Cortecchia, Daniele; Yin, Jun; Bruno, Annalisa; Soci, Cesare

    2015-01-01

    Despite the widespread use of solution-processable hybrid organic–inorganic perovskites in photovoltaic and light-emitting applications, determination of their intrinsic charge transport parameters has been elusive due to the variability of film preparation and history-dependent device performance. Here we show that screening effects associated to ionic transport can be effectively eliminated by lowering the operating temperature of methylammonium lead iodide perovskite (CH3NH3PbI3) field-eff...

  5. Radiative efficiency of lead iodide based perovskite solar cells

    OpenAIRE

    Kristofer Tvingstedt; Olga Malinkiewicz; Andreas Baumann; Carsten Deibel; Snaith, Henry J.; Vladimir Dyakonov; Bolink, Henk J.

    2015-01-01

    The maximum efficiency of any solar cell can be evaluated in terms of its corresponding ability to emit light. We herein determine the important figure of merit of radiative efficiency for Methylammonium Lead Iodide perovskite solar cells and, to put in context, relate it to an organic photovoltaic (OPV) model device. We evaluate the reciprocity relation between electroluminescence and photovoltaic quantum efficiency and conclude that the emission from the perovskite devices is dominated by a...

  6. Ionic transport in hybrid lead iodide perovskite solar cells

    OpenAIRE

    Eames, Christopher; Frost, Jarvist Moore; Piers R. F. Barnes; O'Regan, Brian C.; Walsh, Aron; Islam, M. Saiful

    2015-01-01

    Solar cells based on organic–inorganic halide perovskites have recently shown rapidly rising power conversion efficiencies, but exhibit unusual behaviour such as current–voltage hysteresis and a low-frequency giant dielectric response. Ionic transport has been suggested to be an important factor contributing to these effects; however, the chemical origin of this transport and the mobile species are unclear. Here, the activation energies for ionic migration in methylammonium lead iodide (CH3NH...

  7. The sodium iodide symporter: its implications for imaging and therapy

    International Nuclear Information System (INIS)

    The sodium iodide symporter (NIS) is an intrinsic plasma membrane glycoprotein that mediates the active transport of iodide in the thyroid gland and a number of extrathyroidal tissues, in particular lactating mammary gland. In addition to its key function in thyroid physiology, NIS-mediated iodide accumulation allows diagnostic thyroid scintigraphy as well as therapeutic radioiodine application in benign and malignant thyroid disease. NIS therefore represents one of the oldest targets for molecular imaging and therapy. Based on the effective administration of radioiodine that has been used for over 60 years in the management of follicular cell-derived thyroid cancer, cloning and characterization of the NIS gene has paved the way for the development of a novel cytoreductive gene therapy strategy based on targeted NIS expression in thyroidal and nonthyroidal cancer cells followed by therapeutic application of 131I or alternative radionuclides, including 188Re and 211At. In addition, the possibility of direct and non-invasive imaging of functional NIS expression by 123I- and 99mTc-scintigraphy or 124I-PET-imaging allows the application of NIS as a novel reporter gene. In conclusion, the dual role of NIS as diagnostic and therapeutic gene and the detection of extra-thyroidal endogenous NIS expression in breast cancer open promising perspectives in nuclear medicine and molecular oncology for diagnostic and therapeutic application of NIS outside the thyroid gland. (orig.)

  8. Synthesis and evaluation of iodide uptake inhibitors in thyroid gland

    International Nuclear Information System (INIS)

    This work was intended to discover small organic molecules acting as iodide uptake inhibitors in thyroid cells. These compounds can indeed be derivatized into biochemical probes for further characterization of proteins involved in iodide transport mechanisms. On the long term, these inhibitors also appear as attractive drug candidates for treatment of thyroid pathologies or radioprotection against iodine isotopes. A similar strategy was adopted for both of the two inhibitor families. First, we synthesized a chemical library of around 100 analogues; we measured their IC50 against iodide uptake in FRTL-5 cells to get structure-activity relationships. Absolute configuration of stereo-genic centers was also investigated, and a preferential stereochemistry was found to be responsible for activity. From this basis, around twenty 'second-generation' analogues were synthesized by combining fragments contributing to biological activity. Biological evaluation indicated that nine were very potent inhibitors, with IC50 ≤ 6 nM and satisfying physicochemical properties required for drug candidates. Finally, one photoactivatable biotinylated probe was developed in each family and used for photoaffinity labeling. Several specifically labeled proteins are still under identification and constitute new potential therapeutic targets. (author)

  9. Gold nanoelectrode ensembles for direct trace electroanalysis of iodide.

    Science.gov (United States)

    Pereira, Francisco C; Moretto, Ligia M; De Leo, Manuela; Zanoni, Maria V Boldrin; Ugo, Paolo

    2006-08-01

    A procedure for the standardization of ensembles of gold nanodisk electrodes (NEE) of 30 nm diameter is presented, which is based on the analytical comparison between experimental cyclic voltammograms (CV) obtained at the NEEs in diluted solutions of redox probes and CV patterns obtained by digital simulation. Possible origins of defects sometimes found in NEEs are discussed. Selected NEEs are then employed for the study of the electrochemical oxidation of iodide in acidic solutions. CV patterns display typical quasi-reversible behavior which involves associated chemical reactions between adsorbed and solution species. The main CV characteristics at the NEE compare with those observed at millimeter sized gold disk electrodes (Au-macro), apart a slight shift in E1/2 values and slightly higher peak to peak separation at the NEE. The detection limit (DL) at NEEs is 0.3 microM, which is more than one order of magnitude lower than DL at the Au-macro (4 microM). The mechanism of the electrochemical oxidation of iodide at NEEs is discussed. Finally, NEEs are applied to the direct determination of iodide at micromolar concentration levels in real samples, namely in some ophthalmic drugs and iodized table salt.

  10. Enhanced iodide sequestration by 3-biphenyl-5,6-dihydroimidazo 2,1-b thiazole in sodium/iodide sym-porter (NIS)-expressing cells

    International Nuclear Information System (INIS)

    The ability of the sodium/iodide sym-porter (NIS) to take up iodide has long provided the basis for cyto-reductive gene therapy and cancer treatment with radio-iodide. One of the major limitations of this approach is that radio-iodide retention in NIS-expressing cells is not sufficient for their destruction. We identified and characterized a small organic molecule capable of increasing iodide retention in HEK293 cells permanently transfected with human NIS cDNA (hNIS-HEK293) and in the rat thyroid-derived cell line FRTL-5. In the presence of 3-biphenyl-4'-yl-5,6-dihydroimidazo[2,1-b)thiazole (ISA1), the transmembrane iodide concentration gradient was increased up to 4.5-fold. Our experiments indicate that the imidazo-thiazole derivative acts either by inhibiting anion efflux mechanisms, or by promoting the relocation of iodide into subcellular compartments. This new compound is not only an attractive chemical tool to investigate the mechanisms of iodide flux at the cellular level, but also opens promising perspectives in the treatment of cancer after NIS gene transfer. (authors)

  11. Enhanced iodide sequestration by 3-biphenyl-5,6-dihydroimidazo 2,1-b thiazole in sodium/iodide sym-porter (NIS)-expressing cells

    Energy Technology Data Exchange (ETDEWEB)

    Lecat-Guillet, N.; Ambroise, Y. [CEA, DSV, Dept Bioorgan Chem andt IsotopLabelling, Inst Biol and Technol, iBiTecS, F-91191 Gif Sur Yvette (France)

    2008-07-01

    The ability of the sodium/iodide sym-porter (NIS) to take up iodide has long provided the basis for cyto-reductive gene therapy and cancer treatment with radio-iodide. One of the major limitations of this approach is that radio-iodide retention in NIS-expressing cells is not sufficient for their destruction. We identified and characterized a small organic molecule capable of increasing iodide retention in HEK293 cells permanently transfected with human NIS cDNA (hNIS-HEK293) and in the rat thyroid-derived cell line FRTL-5. In the presence of 3-biphenyl-4'-yl-5,6-dihydroimidazo[2,1-b)thiazole (ISA1), the transmembrane iodide concentration gradient was increased up to 4.5-fold. Our experiments indicate that the imidazo-thiazole derivative acts either by inhibiting anion efflux mechanisms, or by promoting the relocation of iodide into subcellular compartments. This new compound is not only an attractive chemical tool to investigate the mechanisms of iodide flux at the cellular level, but also opens promising perspectives in the treatment of cancer after NIS gene transfer. (authors)

  12. 40 CFR 721.775 - Brominated aromatic com-pound (generic name).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Brominated aromatic com-pound (generic name). 721.775 Section 721.775 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED... Specific Chemical Substances § 721.775 Brominated aromatic com-pound (generic name). (a)...

  13. Visible-light photoredox catalysis enabled bromination of phenols and alkenes

    Directory of Open Access Journals (Sweden)

    Yating Zhao

    2014-03-01

    Full Text Available A mild and efficient methodology for the bromination of phenols and alkenes has been developed utilizing visible light-induced photoredox catalysis. The bromine was generated in situ from the oxidation of Br− by Ru(bpy33+, both of which resulted from the oxidative quenching process.

  14. The Evolution of a Green Chemistry Laboratory Experiment: Greener Brominations of Stilbene

    Science.gov (United States)

    McKenzie, Lallie C.; Huffman, Lauren M.; Hutchison, James E.

    2005-01-01

    The use of green metrics to compare three bromination laboratory procedures demonstrates the effectiveness of an incremental greening process for chemistry curricula. Due to this process, the bromination of alkenes can be introduced to students through the use of a safe, effective, modern practice.

  15. Accurate measurement of bromine contents in plastic samples by instrumental neutron activation analysis.

    Science.gov (United States)

    Kim, I J; Lee, K S; Hwang, E; Min, H S; Yim, Y H

    2013-03-26

    Accurate measurements of bromine contents in plastic samples were made by the direct comparator instrumental neutron activation analysis (INAA). Individual factors affecting the measurements were comprehensively evaluated and compensated, including the volatility loss of bromine from standard comparators, the background bromine level in the filter papers used for preparation of the standard comparators, nuclear interference, γ-ray spectral interference and the variance among replicates of the samples. Uncertainty contributions from those factors were thoroughly evaluated and included in the uncertainty budgeting of the INAA measurement. (81)Br was chosen as the target isotope, and the INAA measurements for bromine were experimentally confirmed to exhibit good linearity within a bromine content range of 10-170 μg. The established method has been applied to the analysis of eight plastic samples: four commercially available certified reference materials (CRMs) of polyethylene and polystyrene and four acrylonitrile butadiene styrene (ABS) samples prepared as the candidate reference materials (KRISS CRM 113-01-012, -013, -014 and -015). The bromine contents of the samples were calculated at three different γ-ray energies and compared, showing good agreement. The results of the four CRMs also showed good consistency with their certified values within the stated uncertainties. Finally, the bromine contents of the ABS samples were determined with expanded uncertainties (at a 95% level of confidence) between 2.5% and 5% in a bromine content range of 25-900 mg kg(-1). PMID:23498117

  16. The Cyclotron Production and Nuclear Imaging of BROMINE-77.

    Science.gov (United States)

    Galiano, Eduardo

    In this investigation, bromine-77 was produced with a medical cyclotron and imaged with gamma cameras. Br -77 emits a 240 kev photon with a half life of 56 hours. The C-Br bond is stronger than the C-I bond and bromine is not collected in the thyroid. Bromine can be used to label many organic molecules by methods analogous to radioiodination. The only North American source of Br-77 in the 70's and 80's was Los Alamos National Laboratory, but it discontinued production in 1989. In this method, a p,3n reaction on Br-77 produces Kr-77 which decays with a 1.2 hour half life to Br-77. A cyclotron generated 40 MeV proton beam is incident on a nearly saturated NaBr or LiBr solution contained in a copper or titanium target. A cooling chamber through which helium gas is flowed separates the solution from the cyclotron beam line. Helium gas is also flowed through the solution to extract Kr-77 gas. The mixture flows through a nitrogen trap where Kr-77 freezes and is allowed to decay to Br-77. Eight production runs were performed, three with a copper target and five with a titanium target with yields of 40, 104, 180, 679, 1080, 685, 762 and 118 uCi respectively. Gamma ray spectroscopy has shown the product to be very pure, however corrosion has been a major obstacle, causing the premature retirement of the copper target. Phantom and in-vivo rat nuclear images, and an autoradiograph in a rat are presented. The quality of the nuclear scans is reasonable and the autoradiograph reveals high isotope uptake in the renal parenchyma, a more moderate but uniform uptake in pulmonary and hepatic tissue, and low soft tissue uptake. There is no isotope uptake in the brain or the gastric mucosa.

  17. Preparation of bromine-77 labeled proteins using bromoperoxidase

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, F.; Slegers, G. (Ghent Univ. (Belgium). Lab. of Radiopharmacy)

    1994-01-01

    The halogenating enzyme bromoperoxidase, isolated from the brown algae Ascophyllum nodosum, was used to catalyze the radiobromination of an anti-hPLAP monoclonal antibody. Radiobromination of bovine serum albumin was also performed and used as control method. The proteins are labeled with bromine-77, produced by the [sup 75]As ([alpha], 2n) [sup 77]Br reaction. The essential reaction parameters, such as concentration of protein and hydrogen peroxide, the amount of bromoperoxidase, the pH of the reaction mixture, the reaction time and temperature were optimized. The immunoreactivity of the radiolabeled monoclonal antibody was checked with a ''Sandwich'' ELISA. (author).

  18. Future chlorine-bromine loading and ozone depletion

    Science.gov (United States)

    Prather, Michael J.; Ibrahim, Abdel Moneim; Sasaki, Toru; Stordal, Frode; Visconti, Guido

    1991-01-01

    The prediction of future ozone requires three elements: (1) a scenario for the net emissions of chemically and radiatively active trace gases from the land and oceans; (2) a global atmospheric model that projects the accumulation of these gases; and (3) a chemical transport model that describes the distribution of ozone for a prescribed atmospheric composition and climate. This chapter, of necessity, presents models for all three elements and focuses on the following: (1) atmospheric abundance of chlorine and bromine in the form of halocarbons; and (2) the associated perturbations to stratospheric ozone.

  19. Electrochemistry of silver iodide the capacity of the double layer at the silver iodide-water interface

    NARCIS (Netherlands)

    Lyklema, J.; Overbeek, J.Th.G.

    1961-01-01

    A method is described for obtaining differential double layer capacities on silver iodide. Especially the influence of the nature and concentration of indifferent electrolytes was investigated, viz., the nitrates of Li·, K·, Rb·, NH4·, H·, Tl·, Mg··, Ba··, Co··, Cd··, Pb··, La···, Th····, the fluori

  20. Labeling of receptor ligands with bromine radionuclides. Progress report, March 1, 1981-February 28, 1982

    International Nuclear Information System (INIS)

    In recent years there has been an interest in the use of various radioisotopes of bromine as labels for radiopharmaceuticals. Although radioisotopes of iodine have been used extensively as radiopharmaceutical labels, there are several advantages associated with the use of radiobromine as a label, due primarily to increased stability of bonds to the radiohalide and smaller steric perturbation resulting from substitution of the radiohalide. Methods of attaching radiobromine to receptor ligands with the potential of mapping estrogen receptors in mammary tumors and uteri were studied. Two ligands were studied extensively in vitro and in animal models; preliminary studies were also carried out in humans. To date, the only radioisotope of bromine used was bromine-77. In addition, a series of model compounds were labeled with bromine-77 using a recently described method for rapid bromination; the scope and limitations of this new rapid radiobromination technique were evaluated

  1. Effect of bromine substituents in the formation of PXDD from poly halogenated phenols

    Energy Technology Data Exchange (ETDEWEB)

    Sakurai, T.; Ohono, T.; Weber, R.

    2002-07-01

    The condensation of chlorophenols has been studied extensively in the last two decades and was discussed as one mechanism in particular for the formation of PCDD in thermal processes. Brominated flame retardants and brominated and brominated-chlorinated dibenzodioxins and dibenzofurans have received increased attention recently due to the growing use of brominated flame retardants during the last decade. This is resulting than increase of brominated compounds in waste (e.g. Electric and electronic shredder waste), containing a considerable amount of bromine, in the form of brominated flame retardants. Many studies reported on the formation of PBDD/PBDF from brominated diphenylethers, or bromophenosl. However with the exception of Sodhu et al, a comparison of the condensation behaviour of bromophenols and chlorophenols was not done. The condensation of brominated phenols is interesting from several aspects. Bromophenols are used as flame retardants and might be a source of PBDD/F during thermal stress. Bromophenols can also be generated during the combustion/pyrolysis of bromodiphenylether or tetrabromobisphenol A containing material, serving as potential precursors for the formation of PBDD/PBDF. Further, in municipal waste incinerators with sufficient secondary combustion, the largest amount of chlorinated aromatic compounds (PCDD, PCDF, PCBs, PCNs, and chlorophenols) are formed in the cooling section (boiler, duct, dust filtration). Therefore in combustion processes involving high concentrations of brominated flame retardants, mixed PXDD/PXDF might be formed by condensation reactions of precursors or de novo synthesis in the cooling zone. Therefore we investigated the condensation of abrominated phenol in more detail and compare it to the condensation reaction of the analogous chlorophenol. (Author)

  2. Algae form brominated organic compounds in surface waters

    Energy Technology Data Exchange (ETDEWEB)

    Huetteroth, A.; Putschew, A.; Jekel, M. [Tech. Univ. Berlin (Germany)

    2004-09-15

    Monitoring of organic halogen compounds, measured as adsorbable organic bromine (AOBr) revealed seasonal high concentrations of organic bromine compounds in a surface water (Lake Tegel, Berlin, Germany). Usually, in late summer, concentrations are up to five times higher than during the rest of the year. The AOBr of the lake inflows (throughout the year less then 6 {mu}g/L) were always lower then those in the lake, which indicates a production of AOBr in the lake. A correlation of the AOBr and chlorophyll-a concentration (1) in the lake provides first evidence for the influence of phototrophic organisms. The knowledge of the natural production of organohalogens is relatively recent. Up to now there are more then 3800 identified natural organohalogen compounds that have been detected in marine plants, animals, and bacteria and also in terrestrial plants, fungi, lichen, bacteria, insects, some higher animals, and humans. Halogenated organic compounds are commonly considered to be of anthropogenic origin; derived from e.g. pharmaceuticals, herbicides, fungicides, insecticides, flame retardants, intermediates in organic synthesis and solvents. Additionally they are also produced as by-products during industrial processes and by waste water and drinking water disinfection. Organohalogen compounds may be toxic, persistent and/or carcinogenic. In order to understand the source and environmental relevance of naturally produced organobromine compounds in surface waters, the mechanism of the formation was investigated using batch tests with lake water and algae cultures.

  3. Comparative environmental analysis of waste brominated plastic thermal treatments

    International Nuclear Information System (INIS)

    The aim of this research activity is to investigate the environmental impact of different thermal treatments of waste electric and electronic equipment (WEEE), applying a life cycle assessment methodology. Two scenarios were assessed, which both allow the recovery of bromine: (A) the co-combustion of WEEE and green waste in a municipal solid waste combustion plant, and (B) the staged-gasification of WEEE and combustion of produced syngas in gas turbines. Mass and energy balances on the two scenarios were set and the analysis of the life cycle inventory and the life cycle impact assessment were conducted. Two impact assessment methods (Ecoindicator 99 and Impact 2002+) were slightly modified and then used with both scenarios. The results showed that scenario B (staged-gasification) had a potentially smaller environmental impact than scenario A (co-combustion). In particular, the thermal treatment of staged-gasification was more energy efficient than co-combustion, and therefore scenario B performed better than scenario A, mainly in the impact categories of 'fossil fuels' and 'climate change'. Moreover, the results showed that scenario B allows a higher recovery of bromine than scenario A; however, Br recovery leads to environmental benefits for both the scenarios. Finally the study demonstrates that WEEE thermal treatment for energy and matter recovery is an eco-efficient way to dispose of this kind of waste

  4. Maternal exposure to brominated flame retardants and infant Apgar scores.

    Science.gov (United States)

    Terrell, Metrecia L; Hartnett, Kathleen P; Lim, Hyeyeun; Wirth, Julie; Marcus, Michele

    2015-01-01

    Brominated flame retardants (BFRs) and other persistent organic pollutants have been associated with adverse health outcomes in humans and may be particularly toxic to the developing fetus. We investigated the association between in utero polybrominated biphenyl (PBB) and polychlorinated biphenyl (PCB) exposures and infant Apgar scores in a cohort of Michigan residents exposed to PBB through contaminated food after an industrial accident. PBB and PCB concentrations were measured in serum at the time the women were enrolled in the cohort. PBB concentrations were also estimated at the time of conception for each pregnancy using a validated elimination model. Apgar scores, a universal measure of infant health at birth, measured at 1 and 5min, were taken from birth certificates for 613 offspring born to 330 women. Maternal PCB concentrations at enrollment were not associated with below-median Apgar scores in this cohort. However, maternal PBB exposure was associated with a dose-related increase in the odds of a below-median Apgar score at 1min and 5min. Among infants whose mothers had an estimated PBB at conception above the limit of detection of 1 part per billion (ppb) to Apgar score increased with higher maternal PBB at conception. It remains critical that future studies examine possible relationships between in utero exposures to brominated compounds and adverse health outcomes.

  5. Abiotic formation of methyl iodide on synthetic birnessite: A mechanistic study

    Energy Technology Data Exchange (ETDEWEB)

    Allard, Sébastien, E-mail: s.allard@curtin.edu.au; Gallard, Hervé

    2013-10-01

    Methyl iodide is a well-known volatile halogenated organic compound that contributes to the iodine content in the troposphere, potentially resulting in damage to the ozone layer. Most methyl iodide sources derive from biological activity in oceans and soils with very few abiotic mechanisms proposed in the literature. In this study we report that synthetic manganese oxide (birnessite δ-MnO{sub 2}) can catalyze the formation of methyl iodide in the presence of natural organic matter (NOM) and iodide. Methyl iodide formation was only observed at acidic pH (4–5) where iodide is oxidized to iodine and NOM is adsorbed on δ-MnO{sub 2}. The effect of δ-MnO{sub 2}, iodide and NOM concentrations, nature of NOM and ionic strength was investigated. High concentrations of methyl iodide were formed in experiments conducted with the model compound pyruvate. The Lewis acid property of δ-MnO{sub 2} leads to a polarization of the iodine molecule, and catalyzes the reaction with natural organic matter. As manganese oxides are strong oxidants and are ubiquitous in the environment, this mechanism could significantly contribute to the global atmospheric input of iodine. Highlights: • Methyl iodide is formed when iodide, natural organic matter and MnO{sub 2} are in contact. • Iodide is oxidized to iodine by MnO{sub 2} which reacts with NOM already adsorbed on MnO{sub 2}. • High formation of methyl iodide was observed with pyruvate. • This abiotic mechanism could contribute to the input of iodine in the atmosphere. • This abiotic mechanism could impact the ozone layer in the troposphere.

  6. Abiotic formation of methyl iodide on synthetic birnessite: A mechanistic study

    International Nuclear Information System (INIS)

    Methyl iodide is a well-known volatile halogenated organic compound that contributes to the iodine content in the troposphere, potentially resulting in damage to the ozone layer. Most methyl iodide sources derive from biological activity in oceans and soils with very few abiotic mechanisms proposed in the literature. In this study we report that synthetic manganese oxide (birnessite δ-MnO2) can catalyze the formation of methyl iodide in the presence of natural organic matter (NOM) and iodide. Methyl iodide formation was only observed at acidic pH (4–5) where iodide is oxidized to iodine and NOM is adsorbed on δ-MnO2. The effect of δ-MnO2, iodide and NOM concentrations, nature of NOM and ionic strength was investigated. High concentrations of methyl iodide were formed in experiments conducted with the model compound pyruvate. The Lewis acid property of δ-MnO2 leads to a polarization of the iodine molecule, and catalyzes the reaction with natural organic matter. As manganese oxides are strong oxidants and are ubiquitous in the environment, this mechanism could significantly contribute to the global atmospheric input of iodine. Highlights: • Methyl iodide is formed when iodide, natural organic matter and MnO2 are in contact. • Iodide is oxidized to iodine by MnO2 which reacts with NOM already adsorbed on MnO2. • High formation of methyl iodide was observed with pyruvate. • This abiotic mechanism could contribute to the input of iodine in the atmosphere. • This abiotic mechanism could impact the ozone layer in the troposphere

  7. Expression of sodium-iodide symporter in thyroid gland tumors: immunohistochemical study

    Directory of Open Access Journals (Sweden)

    Bondarenko O.O.

    2009-01-01

    Full Text Available One of the key moments of radioiodine therapy, and also radioisotope diagnostics of cancers of a thyroid gland is ability of their cells to accumulate iodide. This ability is provided with activity of the specific transporter – sodium-iodide symporter. Our research has shown disorders of sodium-iodide symporter immunoexpression in all tumors of thyroid gland: from overexpression and absence of plasma membrane expression in differentiated carcinomas, up to weak or actually absent in low differentiated cancers and Hurtle-cells tumors. Thus, there is a prospect of application of the sodium-iodide symporter, as the prognostic marker of thyroid cancers.

  8. Pulse radiolysis studies of the reactions of bromine atoms and dimethyl sulfoxide-bromine atom complexes with alcohols

    International Nuclear Information System (INIS)

    Dimethylsulfoxide (DMSO)-Br complexes were generated by pulse radiolysis of DMSO/bromomethane mixtures and the formation mechanism and spectral characteristics of the formed complexes were investigated in detail. The rate constant for the reaction of bromine atoms with DMSO and the extinction coefficient of the complex were obtained to be 4.6x109 M-1 s-1 and 6300 M-1 cm-1 at the absorption maximum of 430 nm. Rate constants for the reaction of bromine atoms with a series of alcohols were determined in CBrCl3 solutions applying a competitive kinetic method using the DMSO-Br complex as the reference system. The obtained rate constants were ∼108 M-1 s-1, one or two orders larger than those reported for highly polar solvents. Rate constants of DMSO-Br complexes with alcohols were determined to be ∼ 107 M-1 s-1. A comparison of the reactivities of Br atoms and DMSO-Br complexes with those of chlorine atoms and chlorine atom complexes which are ascribed to hydrogen abstracting reactants strongly indicates that hydrogen abstraction from alcohols is not the rate determining step in the case of Br atoms and DMSO-Br complexes

  9. Temperature dependent energy levels of methylammonium lead iodide perovskite

    Energy Technology Data Exchange (ETDEWEB)

    Foley, Benjamin J.; Marlowe, Daniel L.; Choi, Joshua J., E-mail: jjc6z@virginia.edu, E-mail: mgupta@virginia.edu, E-mail: scudiero@wsu.edu [Department of Chemical Engineering, University of Virginia, Charlottesville, Virginia 22904 (United States); Sun, Keye; Gupta, Mool C., E-mail: jjc6z@virginia.edu, E-mail: mgupta@virginia.edu, E-mail: scudiero@wsu.edu [Department of Electrical and Computer Engineering, University of Virginia, Charlottesville, Virginia 22904 (United States); Saidi, Wissam A. [Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pittsburgh, Pennsylvania 15261 (United States); Scudiero, Louis, E-mail: jjc6z@virginia.edu, E-mail: mgupta@virginia.edu, E-mail: scudiero@wsu.edu [Chemistry Department and Materials Science and Engineering Program, Washington State University, Pullman, Washington 99164 (United States)

    2015-06-15

    Temperature dependent energy levels of methylammonium lead iodide are investigated using a combination of ultraviolet photoemission spectroscopy and optical spectroscopy. Our results show that the valence band maximum and conduction band minimum shift down in energy by 110 meV and 77 meV as temperature increases from 28 °C to 85 °C. Density functional theory calculations using slab structures show that the decreased orbital splitting due to thermal expansion is a major contribution to the experimentally observed shift in energy levels. Our results have implications for solar cell performance under operating conditions with continued sunlight exposure and increased temperature.

  10. Mechanochromic and thermochromic luminescence of a copper iodide cluster.

    Science.gov (United States)

    Perruchas, Sandrine; Le Goff, Xavier F; Maron, Sébastien; Maurin, Isabelle; Guillen, François; Garcia, Alain; Gacoin, Thierry; Boilot, Jean-Pierre

    2010-08-18

    The mechanochromic and thermochromic luminescence properties of a molecular copper(I) iodide cluster formulated [Cu(4)I(4)(PPh(2)(CH(2)CH=CH(2)))(4)] are reported. Upon mechanical grinding in a mortar, its solid-state emission properties are drastically modified as well as its thermochromic behavior. This reversible phenomenon has been attributed to distortions in the crystal packing leading to modifications of the intermolecular interactions and thus of the [Cu(4)I(4)] cluster core geometry. Notably, modification of the Cu-Cu interactions seems to be involved in this phenomenon directly affecting the emissive properties of the cluster. PMID:20698644

  11. Persistent photovoltage in methylammonium lead iodide perovskite solar cells

    OpenAIRE

    Baumann, A.; Tvingstedt, K.; Heiber, M. C.; Väth, S.; C. Momblona; H. J. Bolink; Dyakonov, V.

    2014-01-01

    We herein perform open circuit voltage decay (OCVD) measurements on methylammonium lead iodide (CH3NH3PbI3) perovskite solar cells to increase the understanding of the charge carrier recombination dynamics in this emerging technology. Optically pulsed OCVD measurements are conducted on CH3NH3PbI3 solar cells and compared to results from another type of thin-film photovoltaics, namely, the two reference polymer–fullerene bulk heterojunction solar cell devices based on P3HT:PC60BM and PTB7:PC70...

  12. Temperature dependent energy levels of methylammonium lead iodide perovskite

    International Nuclear Information System (INIS)

    Temperature dependent energy levels of methylammonium lead iodide are investigated using a combination of ultraviolet photoemission spectroscopy and optical spectroscopy. Our results show that the valence band maximum and conduction band minimum shift down in energy by 110 meV and 77 meV as temperature increases from 28 °C to 85 °C. Density functional theory calculations using slab structures show that the decreased orbital splitting due to thermal expansion is a major contribution to the experimentally observed shift in energy levels. Our results have implications for solar cell performance under operating conditions with continued sunlight exposure and increased temperature

  13. Measuring Cell Death by Propidium Iodide Uptake and Flow Cytometry.

    Science.gov (United States)

    Crowley, Lisa C; Scott, Adrian P; Marfell, Brooke J; Boughaba, Jeanne A; Chojnowski, Grace; Waterhouse, Nigel J

    2016-01-01

    Propidium iodide (PI) is a small fluorescent molecule that binds to DNA but cannot passively traverse into cells that possess an intact plasma membrane. PI uptake versus exclusion can be used to discriminate dead cells, in which plasma membranes become permeable regardless of the mechanism of death, from live cells with intact membranes. PI is excited by wavelengths between 400 and 600 nm and emits light between 600 and 700 nm, and is therefore compatible with lasers and photodetectors commonly available in flow cytometers. This protocol for PI staining can be used to quantitate cell death in most modern research facilities and universities. PMID:27371595

  14. Polarized spectral complexes of optical functions of monovalent mercury iodide

    Science.gov (United States)

    Sobolev, V. V.; Sobolev, V. Val.; Anisimov, D. V.

    2015-12-01

    Spectral complexes of optical functions of monovalent mercury iodide Hg2I2 were determined for E ⊥ c and E || c polarizations in the range from 2 to 5.5 eV at 4.2 K. The permittivity and characteristic electron energy loss spectra were expanded in simple components with the determination of their main parameters, including the energy of the maximum and the oscillator strength. The calculations were performed based on known reflectance spectra. Computer programs based on Kramers-Kronig relations and the improved parameter-free method of Argand diagrams were used.

  15. Electronic properties and Compton profiles of silver iodide

    Indian Academy of Sciences (India)

    Alpa Dashora; Ambica Marwal; K R Soni; B L Ahuja

    2010-06-01

    We have carried out an extensive study of electronic properties of silver iodide in - and -phases. The theoretical Compton profiles, energy bands, density of states and anisotropies in momentum densities are computed using density functional theories. We have also employed full-potential linearized augmented plane-wave method to derive the energy bands and the density of states. To compare our theoretical data, isotropic Compton profile measurement on -AgI using 137Cs Compton spectrometer at an intermediate resolution of 0.38 a.u. has been undertaken. The theoretical anisotropies are also interpreted on the basis of energy bands.

  16. The contribution of anthropogenic bromine emissions to past stratospheric ozone trends: a modelling study

    Directory of Open Access Journals (Sweden)

    B.-M. Sinnhuber

    2009-04-01

    Full Text Available Bromine compounds play an important role in the depletion of stratospheric ozone. We have calculated the changes in stratospheric ozone in response to changes in the halogen loading over the past decades, using a two-dimensional (latitude/height model constrained by source gas mixing ratios at the surface. Model calculations of the decrease of total column ozone since 1980 agree reasonably well with observed ozone trends, in particular when the contribution from very short-lived bromine compounds is included. Model calculations with bromine source gas mixing ratios fixed at 1959 levels, corresponding approximately to a situation with no anthropogenic bromine emissions, show an ozone column reduction between 1980 and 2005 at Northern Hemisphere mid-latitudes of only ≈55% compared to a model run including all halogen source gases. In this sense anthropogenic bromine emissions are responsible for ≈45% of the model estimated column ozone loss at Northern Hemisphere mid-latitudes. However, since a large fraction of the bromine induced ozone loss is due to the combined BrO/ClO catalytic cycle, the effect of bromine would have been smaller in the absence of anthropogenic chlorine emissions. The chemical efficiency of bromine relative to chlorine for global total ozone depletion from our model calculations, expressed by the so called α-factor, is 64 on an annual average. This value is much higher than previously published results. Updates in reaction rate constants can explain only part of the differences in α. The inclusion of bromine from very short-lived source gases has only a minor effect on the global mean α-factor.

  17. Brominated lipids identify lipid binding sites on the surface of the reaction center from Rhodobacter sphaeroides.

    Science.gov (United States)

    Roszak, Aleksander W; Gardiner, Alastair T; Isaacs, Neil W; Cogdell, Richard J

    2007-03-20

    This study describes the use of brominated phospholipids to distinguish between lipid and detergent binding sites on the surface of a typical alpha-helical membrane protein. Reaction centers isolated from Rhodobacter sphaeroides were cocrystallized with added brominated phospholipids. X-ray structural analysis of these crystals has revealed the presence of two lipid binding sites from the characteristic strong X-ray scattering from the bromine atoms. These results demonstrate the usefulness of this approach to mapping lipid binding sites at the surface of membrane proteins.

  18. Progress in tumor therapy with human sodium iodide symporter

    International Nuclear Information System (INIS)

    The sodium iodide symporter (NIS) is an intrinsic plasma membrane protein that mediates active iodide transport into the thyroid gland and several extrathyroidal tissues, in particular the lactation mammary gland. Because of the cloning characterization of NIS, its key role in thyroid pathology and physiology could be investigated. The progress would be significant if the mechanisms of NIS expression in lactating mammary gland and breast cancer are elucidated, in which more than 80% of cases express endogenous NIS. In the future, two approaches could extend the use of radioiodide treatment to thyroid cancer and nonthyroidal cancer. One is by using the main mechanisms involving tumorous transformation to treat the tumor, based on the reinducing NIS expression in thyroid and cancer. The other is based on the application of NIS as a novel cytoreductive gene therapy strategy. NIS offers the unique advantage that it can be used both as a reporter and as a therapeutic gene, so that it is possible to image, monitor, and treat the tumor with radioiodide, just as in differentiated thyroid cancer. (authors)

  19. Polymorphic copper iodide clusters: insights into the mechanochromic luminescence properties.

    Science.gov (United States)

    Benito, Quentin; Le Goff, Xavier F; Maron, Sébastien; Fargues, Alexandre; Garcia, Alain; Martineau, Charlotte; Taulelle, Francis; Kahlal, Samia; Gacoin, Thierry; Boilot, Jean-Pierre; Perruchas, Sandrine

    2014-08-13

    An in-depth study of mechanochromic and thermochromic luminescent copper iodide clusters exhibiting structural polymorphism is reported and gives new insights into the origin of the mechanochromic luminescence properties. The two different crystalline polymorphs exhibit distinct luminescence properties with one being green emissive and the other one being yellow emissive. Upon mechanical grinding, only one of the polymorphs exhibits great modification of its emission from green to yellow. Interestingly, the photophysical properties of the resulting partially amorphous crushed compound are closed to those of the other yellow polymorph. Comparative structural and optical analyses of the different phases including a solution of clusters permit us to establish a correlation between the Cu-Cu bond distances and the luminescence properties. In addition, the local structure of the [Cu4I4P4] cluster cores has been probed by (31)P and (65)Cu solid-state NMR analysis, which readily indicates that the grinding process modifies the phosphorus and copper atoms environments. The mechanochromic phenomenon is thus explained by the disruption of the crystal packing within intermolecular interactions inducing shortening of the Cu-Cu bond distances in the [Cu4I4] cluster core and eventually modification of the emissive state. These results definitely establish the role of cuprophilic interactions in the mechanochromism of copper iodide clusters. More generally, this study constitutes a step further into the understanding of the mechanism involved in the mechanochromic luminescent properties of metal-based compounds. PMID:25076411

  20. Nuclear detonation, thyroid cancer and potassium iodide prophylaxis

    Directory of Open Access Journals (Sweden)

    Viroj Wiwanitkit

    2011-01-01

    Full Text Available The recent nuclear disaster at Japan has raised global concerns about effects of radioactive leakage in the environment, associated hazards, and how they can be prevented. In this article, we have tried to explain about the guidelines laid down by World Health Organization for a potassium iodide prophylaxis following a nuclear disaster, and its mechanism of action in preventing thyroid cancer. Data was collected mainly from the studies carried out during the Chernobyl disaster of Russia in 1986 and the hazardous effects especially on the thyroid gland were studied. It was seen that radioactive iodine leakage from the nuclear plants mainly affected the thyroid gland, and especially children were at a higher risk at developing the cancers. Potassium Iodide prophylaxis can be administered in order to prevent an increase in the incidence of thyroid cancers in the population of an area affected by a nuclear disaster. However, one has to be cautious while giving it, as using it without indication has its own risks.

  1. Nonradiometric and radiometric testing of radioiodine sorbents using methyl iodide

    International Nuclear Information System (INIS)

    A nonradiometric test of adsorbents and adsorbers with normal methyl iodide (CH3127I) is desirable. Use of methyl radioiodide (CH3131I) requires special precautions and facilities and results in bed contamination. However, first it must be established to what extent the removal of CH3127I by adsorbents is indicative of the removal of CH3131I. An experimental apparatus was built and used to simultaneously measure the penetrations of CH3I molecules and the radioisotope in CH3131I through charcoal absorbent beds. Gas chromatography with electron capture detection was used to measure CH3I. Radioiodine was measured using charcoal traps within NaI scintillation well crystals. Real time (5-min interval) radioiodine measurement provided immediate penetration results directly comparable to the real time penetrations of methyl iodide. These penetrations were compared for typical charcoal adsorbents with these impregnants: (a) 5% KI3, (b) 5% KI3 + 2% TEDA, (c) 5% TEDA, and (d) metal salts (Whetlerite). Differences between CH3I and CH3131I penetrations observed for the two iodized charcoals were attributed to isotope exchange reactions. Equivalent penetrations were observed for non-iodized adsorbents and for iodized ones at initial time. First order rates were confirmed for reactions with TEDA and for isotope exchange. This was one more confirmation of the lack of a challenge concentration effect on efficiencies at low test bed loadings. In addition to other removal mechanisms, reversible physical adsorption was observed with all charcoals

  2. Numerical modelling of methyl iodide in the eastern tropical Atlantic

    Directory of Open Access Journals (Sweden)

    I. Stemmler

    2013-06-01

    Full Text Available Methyl iodide (CH3I is a volatile organic halogen compound that contributes significantly to the transport of iodine from the ocean to the atmosphere, where it plays an important role in tropospheric chemistry. CH3I is naturally produced and occurs in the global ocean. The processes involved in the formation of CH3I, however, are not fully understood. In fact, there is an ongoing debate whether production by phytoplankton or photochemical degradation of organic matter is the main source term. Here, both the biological and photochemical production mechanisms are considered in a biogeochemical module that is coupled to a one-dimensional water column model for the eastern tropical Atlantic. The model is able to reproduce observed subsurface maxima of CH3I concentrations. But, the dominating source process cannot be clearly identified as subsurface maxima can occur due to both direct biological and photochemical production. However, good agreement between the observed and simulated difference between surface and subsurface methyl iodide concentrations is achieved only when direct biological production is taken into account. Production rates for the biological CH3I source that were derived from published laboratory studies are shown to be inappropriate for explaining CH3I concentrations in the eastern tropical Atlantic.

  3. Enhancement of the carbon electrode capacitance by brominated hydroquinones

    Science.gov (United States)

    Gastol, Dominika; Walkowiak, Jedrzej; Fic, Krzysztof; Frackowiak, Elzbieta

    2016-09-01

    This paper presents supercapacitors utilizing new redox-active electrolytes with bromine species. Two sources of Br specimen were investigated, i.e. dibromodihydroxybenzene dissolved in KOH and potassium bromide dissolved in KOH with hydroxybenzene additive. KOH-activated carbon, exhibiting a well-developed porosity, was incorporated as an electrode material. The tested systems revealed a capacitance enhancement explained by Br- and partial BrO3- redox activity. The optimisation of the electrolyte concentration resulted in a capacitance value of 314 F g-1 achieved at 1.1 V voltage range. Good cyclability performance (11% capacitance loss) combined with a high capacitance value (244 F g-1) were obtained for the system operating in 0.2 mol L- 1 C6H4Br2O2 in 2 mol L-1 KOH electrolytic solution.

  4. Selective nitration and bromination of surprisingly ruffled phosphorus corroles.

    Science.gov (United States)

    Pomarico, Giuseppe; Tortora, Luca; Fronczek, Frank R; Smith, Kevin M; Paolesse, Roberto

    2016-05-01

    Phosphorus complexes of corrole have recently attracted increasing interest since these compounds can be easily prepared in good yields, are stable, and show unusual optical properties. For these reasons, phosphorus corroles represent a class of interesting compounds to be exploited in the field of material science or for biomedical investigations and the definition of synthetic pathways for their functionalization is an important step to optimize their properties for various applications. We report here the reactivity of the phosphorus complex of 5,10,15-tritolylcorrole in the nitration or bromination reaction. Both these attempts were successful, allowing the preparation of substituted phosphorus corroles, which can be used as intermediates of more complex architectures endowed with useful properties. Furthermore, the crystallographic characterization of both complexes shows that they have an unusual ruffled geometry of the corrole core, a conformation that has not been considered possible for such a macrocycle.

  5. The third international interlaboratory study on brominated flame retardants

    Energy Technology Data Exchange (ETDEWEB)

    Boer, J. de [Netherlands Institute for Fisheries Research, IJmuiden (Netherlands); Wells, D. [FRS Marine Laboratory, Aberdeen (United Kingdom)

    2004-09-15

    Polybrominated diphenyl ethers (PBDEs) have been produced as brominated flame retardants (BFRs) since the early 1970s and have been found in the aquatic environment since the late 1970s. However, as a result of their detection in sperm whales from deeper Atlantic waters and in human milk, many laboratories are now measuring PBDEs in environmental samples. A first international interlaboratory study (ILS) on the analysis of PBDEs, organised by the Bromine Science and Environmental Forum (BSEF), Brussels, Belgium, in collaboration with the Netherlands Institute for Fisheries Research (RIVO) was conducted in 1999-2000. The results showed that the 18 participating laboratories produced comparable results for BDE 47 in various matrices but had analytical difficulties for other BDEs, in particular for the BDEs 99 and 209. A second study was organised in 2001-2002 by BSEF, QUASIMEME and RIVO. That study showed improvement in comparability of the participating laboratories for BDE99 and some other BDEs. However, there was no improvement for BDE209. Hexabromocyclododecane (HBCD), tetrabromobisphenol-A (TBBP-A) and the dimethyl derivative of TBBP-A (dimethyl TBBP-A) were included in the second study. However, it appeared that only two or three laboratories were able to analyse these determinands. Others laboratories were still in the development phase with their methods for these BFRs. This third study was organised as a development exercise by QUASIMEME, in collaboration with RIVO between September and December 2003. The BFRs selected were the same as in the second study. Two biota test materials, a harbor sediment, a sewage sludge, and two standard solutions were dispatched to the participants.

  6. CuI-catalyzed Synthesis of Aryl Thiocyanates from Aryl Iodides

    Institute of Scientific and Technical Information of China (English)

    Ye Feng WANG; Yuan ZHOU; Jia Rui WANG; Lei LIU; Qing Xiang GUO

    2006-01-01

    An operationally simple and inexpensive catalyst system was developed for the cross coupling of potassium thiocyanate with aryl iodides by using CuI as catalyst, 1, 10-phenanthroline as ligand, and tetraethylammonium iodide as activator. The procedure is applicable for the synthesis of diverse aryl thiocyanates without any exotic, poisonous reagents.

  7. Bibenzimidazole containing mixed ligand cobalt(III) complex as a selective receptor for iodide

    Digital Repository Service at National Institute of Oceanography (India)

    Indumathy, R.; Parameswarana, P.S.; Aiswarya, C.V.; Nair, B.U.

    -, OH- and OAc- do not bring about any dramatic visual colorimetric changes. However, metallo-receptor 2 brings about vivid color change with iodide anion visually and this could be due to charge transfer transition via ion pair formation with iodide ion...

  8. Synthesis, growth, structural, thermal, optical properties of new metal-organic crystals: Methyltriphenylphosphonium iodide thiourea and methyltriphenylphosphonium iodide chloroform hemisolvate

    Science.gov (United States)

    Shivachev, Boris L.; Kossev, Krassimir; Dimowa, Louiza T.; Yankov, Georgi; Petrov, Todor; Nikolova, Rositsa P.; Petrova, Nadia

    2013-08-01

    Crystals of methyltriphenylphosphonium iodide thiourea (1) and methyltriphenylphosphonium iodide chloroform hemisolvate (2) were obtained for the first time. Fourier transform infrared (FTIR) spectral studies have been performed to identify the functional groups. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) were used to study their thermal properties. The optical transmittance window and the lower cutoff wavelength have been identified by UV-vis studies. Crystals of the title compounds suitable for single crystal X-ray analyses were successfully grown by slow evaporation and diffraction data were collected to elucidate the molecular structure and interactions. The proton donors (phosphonium) and proton acceptor (iodine) in the structure of 1 provide infrastructure to introduce charge asymmetry while in 2 chloroform molecule is not involved in the charge transfer. An optical quality crystal of 1 (5×4×2 mm3) was obtained by macroseeding. The crystal has developed facets with major ones (001) and (00¯1). A crystal of 1 was tested with 1060 nm laser radiation and showed second harmonic generation (SHG).

  9. Fabrication of Efficient Low-Bandgap Perovskite Solar Cells by Combining Formamidinium Tin Iodide with Methylammonium Lead Iodide

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Weiqiang; Zhao, Dewei; Yu, Yue; Shrestha, Niraj; Ghimire, Kiran; Grice, Corey R.; Wang, Changlei; Xiao, Yuqing; Cimaroli, Alexander J.; Ellingson, Randy J.; Podraza, Nikolas J.; Zhu, Kai; Xiong, Ren-Gen; Yan, Yanfa

    2016-09-28

    Mixed tin (Sn)-lead (Pb) perovskites with high Sn content exhibit low bandgaps suitable for fabricating the bottom cell of perovskite-based tandem solar cells. In this work, we report on the fabrication of efficient mixed Sn-Pb perovskite solar cells using precursors combining formamidinium tin iodide (FASnI3) and methylammonium lead iodide (MAPbI3). The best-performing cell fabricated using a (FASnI3)0.6(MAPbI3)0.4 absorber with an absorption edge of ~1.2 eV achieved a power conversion efficiency (PCE) of 15.08 (15.00)% with an open-circuit voltage of 0.795 (0.799) V, a short-circuit current density of 26.86(26.82) mA/cm2, and a fill factor of 70.6(70.0)% when measured under forward (reverse) voltage scan. The average PCE of 50 cells we have fabricated is 14.39 +/- 0.33%, indicating good reproducibility.

  10. Dynamic dielectric properties and the γ transition of bromine doped polyacrylonitrile

    Directory of Open Access Journals (Sweden)

    2007-10-01

    Full Text Available Based on monitoring the γ process (the lowest temperature-relaxation in polyacrylonitrile (PAN by dynamic dielectric spectroscopy, new evidence for the formation of a charge transfer complex between bromine dopants and nitrile groups is presented. The experimental work is carried out on PAN and nitrile polymerized PAN with and without bromine doping and the effects of these factors on the γ process are measured. Nitrile polymerization results in diminishing of the γ process and in a 15% increase in its activation energy, whereas bromine doping produces splitting of the original γ process in PAN – coupled with a significant activation energy increase – and its complete disappearance in nitrile polymerized PAN. Both the splitting of the γ process and the higher activation energy reflect bromine-nitrile adduct formation..

  11. Potent competitive interactions of some brominated flame retardants and related compounds with human transthyretin in vitro

    NARCIS (Netherlands)

    Meerts, I.A.T.M.; Zanden, van J.J.; Luijks, E.A.C.; Leeuwen-Bol, van I.; Marsh, G.; Jakobsson, E.; Bergman, A.; Brouwer, A.

    2000-01-01

    Brominated flame retardants such as polybrominated diphenyl ethers (PBDEs), pentabromophenol (PBP), and tetrabromobisphenol A (TBBPA) are produced in large quantities for use in electronic equipment, plastics, and building materials. Because these compounds have some structural resemblance to the th

  12. A Novel Protocol for the Regioselective Bromination of Primary Alcohols in Unprotected Carbohydrates or Glycosides

    Institute of Scientific and Technical Information of China (English)

    薛伟华; 张立芬

    2012-01-01

    The regioselective and efficient bromination of primary hydroxyl groups in unprotected carbohydrates or glycosides is successfully achieved by using (chloro-phenylthio-methylene)dimethylammoniumchloride (CPMA) in the presence of tetrabutylammonium bromide (TBAB) in dry DMF.

  13. Bromine determination by neutron activation analysis and its distribution in the atmosphere

    International Nuclear Information System (INIS)

    Bromine, one of the main participants in ozone layer destruction, is 10 to 100 times more effective than chlorine. There are two principal sources of methyl bromide emissions: the oceans and some pesticides that are used in farming. Bromine was detected in 'premium' and 'magna sin' gasolines (2.86±0.96 and 1.54±0.38 ppm, respectively) as well as in condensed water found in exhaust pipes of vehicles. In addition, samples of rainwater were also analyzed to determine atmospheric bromine concentration. In water samples Br concentrations ranging from 2.09 to 0.06 ppm were found. The techniques utilised were neutron activation analysis and high voltage electrophoresis, the latter to determine the chemical form of bromine in condensed water samples. Finally, suspended particles from rainwater were also analysed by scanning electron microscopy (SEM). (author)

  14. Colorimetric sensing of iodide based on triazole-acetamide functionalized gold nanoparticles

    International Nuclear Information System (INIS)

    We have modified gold nanoparticles (AuNPs) with triazole acetamide to obtain a material for the sensitive and selective colorimetric determination of iodide. The functionalized AuNPs were prepared by a reductive single chemical step using a Cu(I)-catalyzed click reaction. The presence of iodide ions induces the aggregation of these AuNPs and results in a color change from wine-red to purple. The iodide-induced aggregation can be detected visually with bare eyes, but also by photometry. The detection limit is as low as 15 nM. The method displays excellent selectivity for iodide over other anions due to the selective interaction with the amido groups of the triazole. The method was applied to the determination of iodide in spiked lake waters. (author)

  15. New insight into photo-bromination processes in saline surface waters: The case of salicylic acid

    Energy Technology Data Exchange (ETDEWEB)

    Tamtam, Fatima; Chiron, Serge, E-mail: serge.chiron@msem.univ-montp2.fr

    2012-10-01

    It was shown, through a combination of field and laboratory observations, that salicylic acid can undergo photo-bromination reactions in sunlit saline surface waters. Laboratory-scale experiments revealed that the photochemical yields of 5-bromosalicylic acid and 3,5-dibromosalicylic acid from salicylic acid were always low (in the 4% range at most). However, this might be of concern since these compounds are potential inhibitors of the 20{alpha}-hydroxysteroid dehydrogenase enzyme, with potential implications in endocrine disruption processes. At least two mechanisms were involved simultaneously to account for the photo-generation of brominated substances. The first one might involve the formation of reactive brominated radical species (Br{center_dot}, Br{sub 2}{center_dot}{sup -}) through hydroxyl radical mediated oxidation of bromide ions. These ions reacted more selectively than hydroxyl radicals with electron-rich organic pollutants such as salicylic acid. The second one might involve the formation of hypobromous acid, through a two electron oxidation of bromine ions by peroxynitrite. This reaction was catalyzed by nitrite, since these ions play a crucial role in the formation of nitric oxide upon photolysis. This nitric oxide further reacts with superoxide radical anions to yield peroxynitrite and by ammonium through the formation of N-bromoamines, probably due to the ability of N-bromoamines to promote the aromatic bromination of phenolic compounds. Field measurements revealed the presence of salicylic acid together with 5-bromosalicylic and 3,5-dibromosalicylic acid in a brackish coastal lagoon, thus confirming the environmental significance of the proposed photochemically induced bromination pathways. -- Highlights: Black-Right-Pointing-Pointer Brominated derivatives of salicylic acid were detected in a brackish lagoon. Black-Right-Pointing-Pointer A photochemical pathway was hypothesized to account for bromination of salicylic acid. Black

  16. METHOD OF SEPARATING URANIUM, PLUTONIUM AND FISSION PRODUCTS BY BROMINATION AND DISTILLATION

    Science.gov (United States)

    Jaffey, A.H.; Seaborg, G.T.

    1958-12-23

    The method for separation of plutonium from uranium and radioactive fission products obtained by neutron irradiation of uranlum consists of reacting the lrradiated material with either bromine, hydrogen bromide, alumlnum bromide, or sulfur and bromine at an elevated temperature to form the bromides of all the elements, then recovering substantlally pure plutonium bromide by dlstillatlon in combinatlon with selective condensatlon at prescribed temperature and pressure.

  17. Bromine-lithium exchange: An efficient tool in the modular construction of biaryl ligands.

    Science.gov (United States)

    Bonnafoux, Laurence; Leroux, Frédéric R; Colobert, Françoise

    2011-01-01

    Regioselective bromine-lithium exchange reactions on polybrominated biaryls enable the modular synthesis of various polysubstituted biphenyls such as bis(dialkylphosphino)-, bis(diarylphosphino)- and dialkyl(diaryl)phosphinobiphenyls. All permutations of substituents at the ortho positions of the biphenyls are possible. In a similar manner, one can gain access to monophosphine analogues. So far, such a process, based on the effective discrimination between bromine atoms as a function of their chemical environment, has been observed only sporadically.

  18. Bromine atom production and chain propagation during springtime Arctic ozone depletion events in Barrow, Alaska

    OpenAIRE

    Thompson, Chelsea R.; Shepson, Paul B.; Liao, Jin; Huey, L. Greg; Cantrell, Chris; Flocke, Frank; Orlando, John

    2016-01-01

    Ozone depletion events (ODEs) in the Arctic are primarily controlled by a bromine radical-catalyzed destruction mechanism that depends on the efficient production and recycling of Br atoms. Numerous laboratory and modeling studies have suggested the importance of heterogeneous recycling of Br through HOBr reaction with bromide on saline surfaces. However, the gas-phase regeneration of bromine atoms through BrO-BrO radical reactions has been assumed to be an efficient, if not dominant, pa...

  19. Gaia Paradigm: A Biotic Origin Of The Polar Sunrise Arctic Bromine Explosion

    OpenAIRE

    Iudin, M.

    2008-01-01

    The main attention is given to discussion of the natural causes and regularities of the Arctic bromine pollution. We make notice of marine microbial organisms and their metabolism as a prime driving force for the elemental biogeochemical cycles. One of the important conclusions of this study is on similarity between ocean bromine concentrating as by-product of the marine microbial activities and nitrogen fixation by soil bacteria. In both cases, microbial organisms and their food webs maintai...

  20. Performance and Degradation of A Lithium-Bromine Rechargeable Fuel Cell Using Highly Concentrated Catholytes

    OpenAIRE

    Bai, Peng; Bazant, Martin Z.

    2016-01-01

    Lithium-air batteries have been considered as ultimate solutions for the power source of long-range electrified transportation, but state-of-the-art prototypes still suffer from short cycle life, low efficiency and poor power output. Here, a lithium-bromine rechargeable fuel cell using highly concentrated bromine catholytes is demonstrated with comparable specific energy, improved power density, and higher efficiency. The cell is similar in structure to a hybrid-electrolyte Li-air battery, wh...

  1. Vanadate-dependent bromoperoxidases from Ascophyllum nodosum in the synthesis of brominated phenols and pyrroles.

    Science.gov (United States)

    Wischang, Diana; Radlow, Madlen; Hartung, Jens

    2013-09-01

    Bromoperoxidases from the brown alga Ascophyllum nodosum, abbreviated as V(Br)PO(AnI) and V(Br)PO(AnII), show 41% sequence homology and differ by a factor of two in the percentage of α-helical secondary structures. Protein monomers organize into homodimers for V(Br)PO(AnI) and hexamers for V(Br)PO(AnII). Bromoperoxidase II binds hydrogen peroxide and bromide by approximately one order of magnitude stronger than V(Br)PO(AnI). In oxidation catalysis, bromoperoxidases I and II turn over hydrogen peroxide and bromide similarly fast, yielding in morpholine-4-ethanesulfonic acid (MES)-buffered aqueous tert-butanol (pH 6.2) molecular bromine as reagent for electrophilic hydrocarbon bromination. Alternative compounds, such as tribromide and hypobromous acid are not sufficiently electrophilic for being directly involved in carbon-bromine bond formation. A decrease in electrophilicity from bromine via hypobromous acid to tribromide correlates in a frontier molecular orbital (FMO) analysis with larger energy gaps between the π-type HOMO of, for example, an alkene and the σ*(Br,X)-type LUMO of the bromination reagent. By using this approach, the reactivity of substrates and selectivity for carbon-bromine bond formation in reactions mediated by vanadate-dependent bromoperoxidases become predictable, as exemplified by the synthesis of bromopyrroles occurring naturally in marine sponges of the genera Agelas, Acanthella, and Axinella. PMID:23881071

  2. Photothermally induced bromination of carbon/polymer bipolar plate materials for fuel cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Schade, Martin; Franzka, Steffen [Fakultät für Chemie, Universität Duisburg-Essen, 45117 Essen (Germany); Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Carl-Benz-Straße 199, 47057 Duisburg (Germany); Cappuccio, Franco; Peinecke, Volker; Heinzel, Angelika [Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Carl-Benz-Straße 199, 47057 Duisburg (Germany); Zentrum für BrennstoffzellenTechnik (ZBT), Carl-Benz-Straße 201, 47057 Duisburg (Germany); Hartmann, Nils, E-mail: nils.hartmann@uni-due.de [Fakultät für Chemie, Universität Duisburg-Essen, 45117 Essen (Germany); Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Carl-Benz-Straße 199, 47057 Duisburg (Germany)

    2015-05-01

    Graphical abstract: - Highlights: • Photothermal laser bromination of carbon/polymer materials is demonstrated. • Using a microfocused laser functionalized domains with diameters of 5 μm and 100 μm and more can be fabricated. • Bromine groups can be transformed in a variety of other chemical functionalities, i.e. amine groups. • Depending on the chemical functionality, the local chemical affinity and wettability is changed. • The routine can be applied to standard bipolar plate materials used for fuel cell applications. - Abstract: A facile photothermal procedure for direct functionalization of carbon/polymer bipolar plate materials is demonstrated. Through irradiation with a microfocused beam of an Ar{sup +}-laser at λ = 514 nm in gaseous bromine and distinct laser powers and pulse lengths local bromination of the carbon/polymer material takes place. At a 1/e spot diameter of 2.1 μm, functionalized surface areas with diameters down to 5 μm are fabricated. In complementary experiments large-area bromination is investigated using an ordinary tungsten lamp. For characterization contact angle goniometry, X-ray photoelectron spectroscopy and electron microscopy in conjunction with labeling techniques are employed. After irradiation bromine groups can easily be substituted by other chemical functionalities, e.g. azide and amine groups. This provides a facile approach in order to fabricate surface patterns and gradient structures with varying wetting characteristics. Mechanistic aspects and prospects of photothermal routines in micropatterning of carbon/polymer materials are discussed.

  3. Springtime surface ozone fluctuations at high Arctic latitudes and their possible relationship to atmospheric bromine

    Science.gov (United States)

    Oltmans, Samuel J.; Sheridan, Patrick J.; Schnell, Russell C.; Winchester, John W.

    1988-01-01

    At high Arctic stations such as Barrow, Alaska, springtime near-surface ozone amounts fluctuate between the highest and lowest values seen during the course of the year. Episodes when the surface ozone concentration is essentially zero last up to several days during this time of year. In the Arctic Gas and Aerosol Sampling Program (AGASP-I and AGASP-II) in 1983 and 1986, it was found that ozone concentrations often showed a very steep gradient in altitude with very low values near the surface. The cold temperatures, and snow-covered ground make it unlikely that the surface itself would rapidly destroy significant amounts of ozone. The AGASP aircraft measurements that found low ozone concentrations in the lowest layers of the troposphere also found that filterable excess bromine (the amount of bromine in excess of the sea salt component) in samples collected wholly or partially beneath the temperature inversion had higher bromine concentrations than other tropospheric samples. Of the four lowest ozone minimum concentrations, three of them were associated with the highest bromine enrichments. Surface measurements of excess filterable bromine at Barrow show a strong seasonal dependence with values rising dramatically early in March, then declining in May. The concentration of organic bromine gases such as bromoform rise sharply during the winter and then begin to decline after March with winter and early spring values at least three times greater than the summer minimum.

  4. Addition of bromine as a diagnostic gas to inertial confinement fusion target microspheres

    International Nuclear Information System (INIS)

    Currently, direct fuel rho r measurements on Inertial Confinement Fusion (ICF) targets by neutron activation of the argon tracer gas mixed with the DT fuel would require a 100 fold increase in neutron yield. Bromine, on the other hand, has excellent properties for neutron activation analysis at neutron yields of 10two' to 108, when present at an internal pressure of from 0.1 to 0.2 atmospheres. Bromine addition is accomplished in a 2 furnace system using the dried-gel method of microsphere production. An upper furnace operated at 15000C is separated from a lower furnace by a cooled zone. The lower furnace is filled with bromine gas and operated at approximately 12500C. The upper furnace is the glass production furnace. The cooled zone in between the upper and lower furnace is to prevent the hot bromine gas from rising into the upper furnace. The microspheres pass through the cooled zone and immediately into the 12500C bromine furnace where the bromine permeates into the spheres

  5. Horizontal Ampoule Growth and Characterization of Mercuric Iodide at Controlled Gas Pressures for X-Ray and Gamma Ray Spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    McGregor, Douglas S. [Kansas State Univ., Manhattan, KS (United States). Semiconductor Materials and Radiological Technologies Lab., Dept. of Nuclear and Mechanical Engineering; Ariesanti, Elsa [Kansas State Univ., Manhattan, KS (United States). Semiconductor Materials and Radiological Technologies Lab., Dept. of Nuclear and Mechanical Engineering; Corcoran, Bridget [Kansas State Univ., Manhattan, KS (United States). Semiconductor Materials and Radiological Technologies Lab., Dept. of Nuclear and Mechanical Engineering

    2004-04-30

    The project developed a new method for producing high quality mercuric iodide crystals of x-ray and gamma spectrometers. Included are characterization of mercuric iodide crystal properties as a function of growth environment and fabrication and demonstration of room-temperature-operated high-resolution mercuric iodide spectrometers.

  6. Strawberry growers wavered over methyl iodide, feared public backlash

    Directory of Open Access Journals (Sweden)

    Julie Guthman

    2016-08-01

    Full Text Available Methyl iodide, once promoted as a suitable alternative to methyl bromide for soil fumigation in strawberry systems, was withdrawn from the market in 2012 after a contentious regulatory battle that revolved around its high toxicity. At the time of its withdrawal, Arysta LifeScience, the maker of the chemical, claimed that it was no longer economically viable. In this study, I investigated what made the chemical nonviable, with a specific focus on growers' nonadoption of it. Interviews with strawberry growers in the four top California strawberry-growing counties revealed that growers' decisions not to use it were primarily related to public disapproval, although the continued availability of methyl bromide and other fumigants played a contributing role by making adoption less urgent. The study results suggest that policies in place during the methyl bromide phaseout did not strongly encourage the development and extension of less toxic alternatives, which undermined the strawberry industry's position.

  7. Betaine potassium iodide dihydrate: a new compound of betaine

    International Nuclear Information System (INIS)

    Betaine potassium iodide dihydrate, [(CH3)3N+CH2COO-]2.KI.2H2O, BKI for short, is a new compound of the aminoacid betaine with a triclinic symmetry and the space group P1-bar at room temperature. The study of dielectric properties provided evidence for the existence of a structural phase transition occurring around 100 K. The spontaneous electric polarization is zero in both phases. A study of dielectric dispersion disclosed two relaxational modes with different relevance in the high and in the low temperature phases. The main features observed in BKI are consistently described by the Landau theory, by assuming a quadratic coupling between the primary order parameter and the electric polarization. (author). Letter-to-the-editor

  8. Mercuric iodide crystals obtained by solvent evaporation using ethanol

    International Nuclear Information System (INIS)

    Millimeter-sized mercuric iodide crystals were fabricated by the solvent evaporation technique using pure ethanol as a solvent. Three different conditions for solution evaporation were tested: (i) in the dark at room temperature; (ii) in the presence of light at room temperature and (iii) in an oven at 40 deg. C. Morphology, structure, optical and electrical properties were investigated using several techniques. Crystals fabricated in the dark show better properties and stability than others, possibly because the larger the energy of the system, the larger the number of induced growth defects. The crystals fabricated in the dark have adequate structure for higher resistivity and activation energy close to half the optical band-gap, as desired. With proper encapsulation these crystals might be good candidates for the development of ionizing radiation sensors.

  9. Photon recycling in lead iodide perovskite solar cells

    Science.gov (United States)

    Pazos-Outón, Luis M.; Szumilo, Monika; Lamboll, Robin; Richter, Johannes M.; Crespo-Quesada, Micaela; Abdi-Jalebi, Mojtaba; Beeson, Harry J.; Vrućinić, Milan; Alsari, Mejd; Snaith, Henry J.; Ehrler, Bruno; Friend, Richard H.; Deschler, Felix

    2016-03-01

    Lead-halide perovskites have emerged as high-performance photovoltaic materials. We mapped the propagation of photogenerated luminescence and charges from a local photoexcitation spot in thin films of lead tri-iodide perovskites. We observed light emission at distances of ≥50 micrometers and found that the peak of the internal photon spectrum red-shifts from 765 to ≥800 nanometers. We used a lateral-contact solar cell with selective electron- and hole-collecting contacts and observed that charge extraction for photoexcitation >50 micrometers away from the contacts arose from repeated recycling between photons and electron-hole pairs. Thus, energy transport is not limited by diffusive charge transport but can occur over long distances through multiple absorption-diffusion-emission events. This process creates high excitation densities within the perovskite layer and allows high open-circuit voltages.

  10. Investigation of sodium iodide hydration and dehydration in moist atmosphere

    International Nuclear Information System (INIS)

    Effect of different factors on NaI hydration and dehydration kinetics under nonequilibrium conditions is studied. NaIx2H2O solid or homogeneous solution is established to be formed at sodium iodide interaction with water vapour depending on air humidity. At low humidity water absorption is not observed. Effect of water vapour pressure, the NaI particle size, the air flux rate over a salt on the absorption rate is studied. The latter points to process rate limitation by diffusion in a gaseous phase. The NaI solution decomposition at light with iodine formation is marked. The character of NaIx2H2O dehydration depends on water vapour removing from the over-salt space. Total water removing before and after crystal hydrate thermal degradation when aqueous solution evaporation occurs, is possible. At 143 deg C the water vapour pressure over solution equals the atmospheric one

  11. Development of mercuric iodide detectors for XAS and XRD measurements

    International Nuclear Information System (INIS)

    A prototype element for an energy dispersive detector (EDD) array was constructed using a Mercuric Iodide detector. Both detector and front end FET could be thermoelectrically cooled. Tested at SSRL, the detector had 250 eV electronic noise and 315 eV resolution at 5.9 keV. K line fluorescence spectra were collected for selected elements between Cl (2622 eV) and Zn (8638 eV). Count rate capability to 60,000 cps was demonstrated. Several detector parameters were measured, including energy linearity, resolution vs. shaping time, and detector dead time. An EXAFS (extended x-ray absorption fine structure) spectrum was recorded and compared to simultaneously collected transmission data

  12. XPS STUDIES ON SURFACE MODIFIED POLY[1-(TRIMETHYLSILYL)-1-PROPYNE] MEMBRANES Ⅱ SURFACE MODIFICATION BY BROMINE VAPOR

    Institute of Scientific and Technical Information of China (English)

    XU Guanfan; SUN Xiaoguang; QIU Xuepeng; ZHANG Jinlan; ZHENG Guodong

    1994-01-01

    Surface modification of poly [ 1-(trimethylsilyl )-1-propyne ] ( PTMSP ) membranes by bromine vapor has been studied. It is shown that Br/C atomic ratio at the surfacesincreased with the time of bromination until about 60 min, then it reached a plateau. The results of XPS and IR studies indicated that the addition of bromine to double bonds and the replacement of H on CH3 by bromine had taken place so that a new peak at 286.0 eV (C-Br)in C1sspectra and some new bands, e. g. at 1220 and 580cm-1,in IR spectra were formed. The fact, Po2, permeability of oxygen, decreased and αO2/N2, separation factor of oxygen relative to nitrogen, increased with bromination time, shows that surface modification of PTMSP by bromine may be an efficient approachto prepare PTMSP membranes used for practical gas separations.

  13. Utilization of a Green Brominating Agent for the Spectrophotometric Determination of Pipazethate HCl in Pure Form and Pharmaceutical Preparations

    OpenAIRE

    Ayman A. Gouda

    2013-01-01

    Five simple, accurate, and sensitive spectrophotometric methods (A–E) have been described for the indirect assay of pipazethate HCl (PZT) either in pure form or in pharmaceutical preparations. The proposed methods are based on the bromination of pipazethate HCl with a solution of excess bromate-bromide mixture in hydrochloric acid medium and subsequent estimation of the residual bromine by different reaction schemes. In the first three methods (A–C), the determination of the residual bromine ...

  14. Evaluation of quaternary ammonium halides for removal of methyl iodide from flowing air streams

    International Nuclear Information System (INIS)

    The quaternary ammonium halides of several tertiary amines were used as impregnants on activated carbon and were tested for methyl iodide penetration in accordance with test Method A, ASTM D3803, 1979, ''Standard Test Methods for Radio-iodine Testing of Nuclear Grade Gas Phase Adsorbents''. The results suggest that the primary removal mechanism for methyl iodide-131 is isotopic exchange with the quaternary ammonium halide. For example, a 5 wt% impregnation of each of the tetramethyl, tetraethyl, tetrapropyl and tetrabutyl ammonium iodides on activated carbon yielded percent penetrations of 0.47, 0.53, 0.78, and 0.08 respectively when tested according to Method A of ASTM D3803. A sample impregnated with 5% tetramethyl ammonium hydroxide gave a methyl iodide penetration of 64.87%, thus supporting the isotopic exchange mechanism for removal. It has been a generally held belief that the success of tertiary amines as impregnants for radioiodine removal is a result of their ability to complex with the methyl iodide. The results of the work indicates that the superiority of the tertiary amines similar to triethylene diamine and quinuclidine, when compared to their straight chain analogs, is a result of their ease in reacting with methyl iodide-127 to form the quaternary ammonium iodide followed by isotopic exchange

  15. Bromine partitioning between olivine and melt at OIB source conditions: Indication for volatile recycling

    Science.gov (United States)

    Joachim, Bastian; Ruzié, Lorraine; Burgess, Ray; Pawley, Alison; Clay, Patricia L.; Ballentine, Christopher J.

    2016-04-01

    Halogens play a key role in our understanding of volatile transport processes in the Earth's mantle. Their moderate (fluorine) to highly (iodine) incompatible and volatile behavior implies that their distribution is influenced by partial melting, fractionation and degassing processes as well as fluid mobilities. The heavy halogens, particularly bromine and iodine, are far more depleted in the Earth's mantle than expected from their condensation temperature (Palme and O'Neill 2014), so that their very low abundances in basalts and peridotites (ppb-range) make it analytically challenging to investigate their concentrations in Earth's mantle reservoirs and their behavior during transport processes (Pyle and Mather, 2009). We used a new experimental technique, which combines the irradiation technique (Johnson et al. 2000), laser ablation and conventional mass spectrometry. This enables us to present the first experimentally derived bromine partition coefficient between olivine and melt. Partitioning experiments were performed at 1500° C and 2.3 GPa, a P-T condition that is representative for partial melting processes in the OIB source region (Davis et al. 2011). The bromine partition coefficient between olivine and silicate melt at this condition has been determined to DBrol/melt = 4.37•10-4± 1.96•10-4. Results show that bromine is significantly more incompatible than chlorine (˜1.5 orders of magnitude) and fluorine (˜2 orders of magnitude) due to its larger ionic radius. We have used our bromine partitioning data to estimate minimum bromine abundances in EM1 and EM2 source regions. We used minimum bromine bulk rock concentrations determined in an EM1 (Pitcairn: 1066 ppb) and EM2 (Society: 2063 ppb) basalt (Kendrick et al. 2012), together with an estimated minimum melt fraction of 0.01 in OIB source regions (Dasgupta et al. 2007). The almost perfect bromine incompatibility results in minimum bromine abundances in EM1 and EM2 OIB source regions of 11 ppb and 20

  16. Non-polar halogenated natural products bioaccumulated in marine samples. II. Brominated and mixed halogenated compounds.

    Science.gov (United States)

    Vetter, Walter; Jun, Wu

    2003-07-01

    Several identified and potential natural brominated bioaccumulative compounds were studied in this work. 4,6-dibromo-2-(2('),4(')-dibromo)phenoxyanisole (BC-2) previously detected in Australian marine mammals and isolated from sponges, was synthesized. Two byproducts (a tetrabromo isomer and a tribromo congener) were investigated as well. The byproducts of the synthesis were not identified in the environmental samples investigated. Previously described natural brominated compounds (BC-1, BC-2, BC-3, BC-10, BC-11, MHC-1) and anthropogenic brominated diphenyl ethers (BDE-47, BDE-99, BDE-100, BDE-154) were detected in a sample of human milk. The sample was from a woman from the Faeroe Islands who frequently consumed fish as well as whale blubber and meat. The most abundant compound originated from the natural tetrabromo phenoxyanisole BC-3 which may have a 3:1 distribution of bromine on the two phenyl units. This sample also accumulated a dibromochloroanisole, as well as a previously unknown mixed halogenated compound (MHC-X) and an unknown, most likely aromatic brominated compound. Co-elutions on a DB-5 column were found for BDE-99 and BC-11 as well as BDE-154 and the unknown brominated compound. This suggests that quantification of these two compounds has to be carried out carefully.Two samples of lower trophic level, namely Baltic cod liver and Mexican mussel tissue, were investigated as well. The cod liver samples contained BDE congeners but also abundant signals for the natural 2,3,3('),4,4('),5,5(')-heptachloro-1(')-methyl-1,2(')-bipyrrole Q1 and tribromoanisole (TBA). The mussel sample contained Q1, TBA, another halogenated anisole, BC-1, BC-2, and BC-3, as well as additional, potential natural brominated compounds in the elution range of tribromophenoxyanisoles. PMID:12738265

  17. An exemplary case of a bromine explosion event linked to cyclone development in the Arctic

    Science.gov (United States)

    Blechschmidt, A.-M.; Richter, A.; Burrows, J. P.; Kaleschke, L.; Strong, K.; Theys, N.; Weber, M.; Zhao, X.; Zien, A.

    2016-02-01

    Intense, cyclone-like shaped plumes of tropospheric bromine monoxide (BrO) are regularly observed by GOME-2 on board the MetOp-A satellite over Arctic sea ice in polar spring. These plumes are often transported by high-latitude cyclones, sometimes over several days despite the short atmospheric lifetime of BrO. However, only few studies have focused on the role of polar weather systems in the development, duration and transport of tropospheric BrO plumes during bromine explosion events. The latter are caused by an autocatalytic chemical chain reaction associated with tropospheric ozone depletion and initiated by the release of bromine from cold brine-covered ice or snow to the atmosphere. In this manuscript, a case study investigating a comma-shaped BrO plume which developed over the Beaufort Sea and was observed by GOME-2 for several days is presented. By making combined use of satellite data and numerical models, it is shown that the occurrence of the plume was closely linked to frontal lifting in a polar cyclone and that it most likely resided in the lowest 3 km of the troposphere. In contrast to previous case studies, we demonstrate that the dry conveyor belt, a potentially bromine-rich stratospheric air stream which can complicate interpretation of satellite retrieved tropospheric BrO, is spatially separated from the observed BrO plume. It is concluded that weather conditions associated with the polar cyclone favoured the bromine activation cycle and blowing snow production, which may have acted as a bromine source during the bromine explosion event.

  18. Excited atomic bromine energy transfer and quenching mechanisms

    Science.gov (United States)

    Johnson, Ray O.

    1993-08-01

    Pulsed and steady-state photolysis experiments have been conducted to determine the rate coefficients for collisional deactivation of the spin-orbit excited state of atomic bromine, Br((sup 2)P(sub 1/2)). Pulsed lifetime studies for quenching by Br2 and CO2 established absolute rate coefficients at room temperature of k(sub Br2) = 1.2 +/- 0.1 x 10(exp-12) and k(sub CO2) = 1.5 +/0.2 x 10(exp-11) cu cm/molecule-s. Steady-state photolysis methods were used to determine the quenching rates for the rare gases, N2, 02, H2, D2, NO, NO2, N2O, SF6, CF4, CH4, CO, CO2, COS, SO2, H2S, HBr, HC1, and HI relative to that for Br2. Quenching rate temperature dependence was examined for Br2, CO2, N2O, HCl, COS, NO, and NO2 for temperatures from 300 to 420 K. Diffusion and three body effects were examined in order to determine the slowest relative quenching rate measurable by this experimental technique.

  19. Untypical bromine corrosion in boilers co-firing biomass

    Directory of Open Access Journals (Sweden)

    A. Hernas

    2012-09-01

    Full Text Available Purpose: The aim of this study was to determine the untypical corrosion resistance of rotary air preheaters in a biomass co-fired power plant.Design/methodology/approach: The selected results of some components of regenerative rotary air preheaters in a biomass co-fired power plant are presented. The macro and microstructure of corroded components of a LUVO preheater after 3 years of service are presented. The chemical composition of corrosion products was determined by X-ray microanalysis.Findings: Data concerning toxicity and identification of PBDEs (Polibrominated diphenyl ethers in the biomass is very limited. The presented research provides information and the proposed corrosion reaction mechanism in environments containing biomass with aggressive compounds like Cl, Si, H and Br.Research limitations/implications: An extended research on PBDEs in power plant fuels is necessary to give a full assessment of the corrosion mechanism in the presented environment; obligatory classification of the co-fired biomass.Originality/value: Firstly, an assessment of the danger for boiler materials co-firing biomass containing brominated organic flame and presentation of the reaction during the corrosion process and degradation of power boiler components in the presented environment. Secondly, the highlighting of the problem that there is a need to properly select and determine the chemical composition of the biomass used.

  20. Brominated flame retardants in Belgian little owl (Athene noctua) eggs

    Energy Technology Data Exchange (ETDEWEB)

    Jaspers, V.; Covaci, A.; Maervoet, J.; Dauwe, T.; Schepens, P.; Eens, M. [Antwerp Univ. (Belgium)

    2004-09-15

    Since the 1960s, polybrominated diphenylethers (PBDEs), a class of brominated flame retardants (BFRs), are widely used in textiles, plastics, electronic equipment and other materials. Their massive use has led to the ubiquitous presence of PBDEs in the environment and in biota in which the PBDE levels seem to increase rapidly. High concentrations of some congeners may cause adverse effects in both wildlife and in human populations1 and this has led to the growing concern of scientists over the last decade and to the need for more data on environmental levels of PBDEs. The little owl (Athene noctua) is a small sedentary predator, which makes it a very suitable biomonitoring species. This owl species feeds on a variety of preys, including small mammals and birds, reptiles, amphibians, earthworms and beetles, depending on the season and the local circumstances. Because very limited information is available about contamination levels in the little owl, a study was conducted to determine the concentrations of PBDEs, polybrominated biphenyls (PBBs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in deserted or addled eggs of little owls in Belgium. Eggs have been used successfully as a monitoring tool for persistent organic pollutants (POPs) in several studies. Although the analysis of POPs in deserted or addled eggs has clear limitations, these can be partially avoided by analysing only highly persistent components, for which the original composition will not change due to 'posthatching' microbiological degradation.

  1. Measurement-based modeling of bromine chemistry in the boundary layer: 1. Bromine chemistry at the Dead Sea

    Directory of Open Access Journals (Sweden)

    E. Tas

    2006-01-01

    Full Text Available The Dead Sea is an excellent natural laboratory for the investigation of Reactive Bromine Species (RBS chemistry, due to the high RBS levels observed in this area, combined with anthropogenic air pollutants up to several ppb. The present study investigated the basic chemical mechanism of RBS at the Dead Sea using a numerical one-dimensional chemical model. Simulations were based on data obtained from comprehensive measurements performed at sites along the Dead Sea. The simulations showed that the high BrO levels measured frequently at the Dead Sea could only partially be attributed to the highly concentrated Br− present in the Dead Sea water. Furthermore, the RBS activity at the Dead Sea cannot solely be explained by a pure gas phase mechanism. This paper presents a chemical mechanism which can account for the observed chemical activity at the Dead Sea, with the addition of only two heterogeneous processes: the "Bromine Explosion" mechanism and the heterogeneous decomposition of BrONO2. Ozone frequently dropped below a threshold value of ~1 to 2 ppbv at the Dead Sea evaporation ponds, and in such cases, O3 became a limiting factor for the production of BrOx (BrO+Br. The entrainment of O3 fluxes into the evaporation ponds was found to be essential for the continuation of RBS activity, and to be the main reason for the jagged diurnal pattern of BrO observed in the Dead Sea area, and for the positive correlation observed between BrO and O3 at low O3 concentrations. The present study has shown that the heterogeneous decomposition of BrONO2 has a great potential to affect the RBS activity in areas influenced by anthropogenic emissions, mainly due to the positive correlation between the rate of this process and the levels of NO2. Further investigation of the influence of the decomposition of BrONO2 may be especially important in understanding the RBS activity at mid-latitudes.

  2. Measurement-based modeling of bromine chemistry in the boundary layer: 1. Bromine chemistry at the Dead Sea

    Directory of Open Access Journals (Sweden)

    A. Pour Biazar

    2006-06-01

    Full Text Available The Dead Sea is an excellent natural laboratory for the investigation of Reactive Bromine Species (RBS chemistry, due to the high RBS levels observed in this area, combined with anthropogenic air pollutants up to several ppb. The present study investigated the chemical mechanism of RBS at the Dead Sea using a numerical one-dimensional chemical model. Simulations were based on data obtained from comprehensive measurements performed at sites along the Dead Sea. The simulations showed that the high BrO levels measured frequently at the Dead Sea could only partially be attributed to the highly concentrated Br− present in the Dead Sea water. Further, the RBS activity at the Dead Sea cannot solely be explained by a pure gas phase mechanism. This paper presents a chemical mechanism which can account for the observed chemical activity at the Dead Sea, with the addition of only two heterogeneous processes: the "Bromine Explosion" mechanism and the heterogeneous decomposition of BrONO2. Ozone frequently dropped below a threshold value of ~1 to 2 ppbv at the Dead Sea evaporation ponds, and in such cases, O3 became a limiting factor for the production of BrOx (BrO+Br. The entrainment of O3 fluxes into the evaporation ponds was found to be essential for the continuation of RBS activity, and to be the main reason for the positive correlation observed between BrO and O3 at low O3 concentrations, and for the jagged diurnal pattern of BrO observed in the Dead Sea area. The present study has shown that the heterogeneous decomposition of BrONO2 has the potential to greatly affect the RBS activity in areas under anthropogenic influence, mainly due to the positive correlation between the rate of this process and the levels of NO2. Further investigation of the influence of the decomposition of BrONO2 may be especially important in understanding the RBS activity at mid-latitudes.

  3. Brominated flame retardants in end-of-life management not problematic regarding formation of brominated dioxins/furans (PBDD/F)

    Energy Technology Data Exchange (ETDEWEB)

    Drohmann, D. [Great Lakes Chemical, Bergisch Gladbach (Germany); Tange, L. [Eurobrom B.V., Rijswijk (Netherlands); Rothenbacher, K. [Bromine Science and Environmental Forum, Brussels (Belgium)

    2004-09-15

    Bromine is used as the building block for some of the most effective flame retarding agents available to the plastics industry today. They are used to protect against the risk of accidental fires in a wide range of products. Brominated flame retardants (BFRs), as all flame retardants, act to decrease the risk of fire by increasing the fire resistance of the materials in which they are applied. There is a perception that BFRs affect adversely the end-of-life management of plastics through formation of brominated dioxins and furans (PBDD/F). In fact, there exists a wide range of data and practical experience demonstrating that the end-of-life management of plastics containing BFRs are fully compliant with legislation setting the strictest limit values for PBDD/F and is fully compatible with an integrated waste management concept. Furthermore, all existing EU Risk Assessments on BFRs according to the European Existing Substance Regulations include an assessment of the potential formation of dioxins and furans. All assessments conclude that the risks along the life-cycle of the chemicals for human health and the environment associated with the potential formation of PBDD/F are negligible. Moreover, two recent Swedish studies found, that consumer products with BFRs emit less pollutants than the same products without any FRs. This paper summarises available studies and presents the latest results regarding potential formation of brominated dioxins and furans in end-of-life management of plastics containing brominated flame retardants. Additionally, before BFR products enter the market they are tested for PBDD/F according to the ''German Dioxin Ordinance''. Depending on the substitution pattern the limit values for PBDD/F are set at <1{mu}g/kg (ppb) respectively <5{mu}g/kg (ppb).

  4. Terminal elimination half-lives of the brominated flame retardants TBBPA, HBCD, and lower brominated PBDEs in humans

    Energy Technology Data Exchange (ETDEWEB)

    Geyer, H.J.; Schramm, K.W.; Feicht, E.A.; Fried, K.W.; Henkelmann, B.; Lenoir, D. [GSF-National Research Center, Institute of Ecological Chemistry, Neuherberg (Germany); Darnerud, P.O.; Aune, M. [Swedish National Food Administration, Uppsala (Sweden); Schmid, P. [Swiss Federal Laboratories for Materials Testing and Research, Laboratory of Organic Chemistry, EMPA Duebendorf (Switzerland); McDonald, T.A. [Office of Environmental Health Assessment, California EPA, Oakland, CA (United States)

    2004-09-15

    Brominated flame retardants (BFRs) are widely used in polymers and textiles and applied in electronic equipment, construction materials, and furniture for the purpose of fire prevention. BFRs with the highest production volume are tetrabromobisphenol A (TBBPA), 1,2,5,6,9,10- hexabromocyclododecanes (HBCDs: {alpha}-HBCD + {beta}-HBCD + {gamma}-HBCD), and polybrominated diphenyl ethers (PBDEs). Several BFRs are highly lipophilic persistent organic pollutants (POPs) which have been identified in the aquatic and terrestrial environment including wildlife and humans. In exposed organisms including humans toxic effects, bioaccumulation, metabolism, and pharmacokinetics (especially half-life t{sub 1/2}) are important criterions in the hazard assessment. The aim of the present study was to estimate the terminal elimination half-lives (t{sub 1/2H}) of the main BFRs from the whole body (also named body-burden half-life) and/or from the adipose tissue (fat) of adult humans. The t{sub 1/2H} data for the following BFRs were evaluated: TBBPA, HBCD, 2,2',4,4'- tetrabromodiphenyl ether (BDE-47), 2,2',4,4',5-pentaBDE (BDE-99), 2,2',4,4',6-pentaBDE (BDE- 100), 2,2',4,4',5,5'-hexaBDE (BDE-153), and 2,2',4,4',5,6-hexaBDE (BDE-154).

  5. GAS SORPTION AND TRANSPORT IN POLY (PHENYLENE OXIDE )(PPO)AND ARYL-BROMINATED PPO MEMBRANES

    Institute of Scientific and Technical Information of China (English)

    JIA Lianda; F.R.SHEU, R.T. CHERN; H.B. HOPFENBERG

    1989-01-01

    The apparent solubility (S), concentration- average diffusivity (D), and permeability (P), for CO2,CH4 and N2 through PPO and aryl- brominated PPO at 35 ℃ for pressure ranging from 1 to 26 atm are reported. It is found that P,D, and Sof the membranes to all the three gases vary with the extent of bromination. S increases with the increase of the perecnt of bromine in each case, but D to CO2 increases remarkably only at higher degree of bromination, and therefore, P to CO2 is increased by more than 100% over a wide range of pressure in the case .The solubility data are well described by the dual mode sorption model. It is found that the gas molecules sorbed by the Langmuir mode are relatively more immobilized and the contribution of the nonequilibrium character of the polymer to gas permeation increases obviously for CO2 and is hardly changed for CH4 with increasing bromine content. These observations are interpreted in terms of changes in specific free volume (SFV)and the cohesive energy density (CED) of the polymers.

  6. Removal of brominated flame retardant from electrical and electronic waste plastic by solvothermal technique

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Cong-Cong [Research Center For Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085 (China); Zhang, Fu-Shen, E-mail: fszhang@rcees.ac.cn [Research Center For Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085 (China)

    2012-06-30

    Highlights: Black-Right-Pointing-Pointer A process for brominated flame retardants (BFRs) removal in plastic was established. Black-Right-Pointing-Pointer The plastic became bromine-free with the structure maintained after this treatment. Black-Right-Pointing-Pointer BFRs transferred into alcohol solvent were easily debrominated by metallic copper. - Abstract: Brominated flame retardants (BFRs) in electrical and electronic (E and E) waste plastic are toxic, bioaccumulative and recalcitrant. In the present study, tetrabromobisphenol A (TBBPA) contained in this type of plastic was tentatively subjected to solvothermal treatment so as to obtain bromine-free plastic. Methanol, ethanol and isopropanol were examined as solvents for solvothermal treatment and it was found that methanol was the optimal solvent for TBBPA removal. The optimum temperature, time and liquid to solid ratio for solvothermal treatment to remove TBBPA were 90 Degree-Sign C, 2 h and 15:1, respectively. After the treatment with various alcohol solvents, it was found that TBBPA was finally transferred into the solvents and bromine in the extract was debrominated catalyzed by metallic copper. Bisphenol A and cuprous bromide were the main products after debromination. The morphology and FTIR properties of the plastic were generally unchanged after the solvothermal treatment indicating that the structure of the plastic maintained after the process. This work provides a clean and applicable process for BFRs-containing plastic disposal.

  7. Effect of the Bromine-Based Flame Retardant Plastic Pyrolysis of Hydrotalcite

    Directory of Open Access Journals (Sweden)

    Morita N.

    2016-01-01

    Full Text Available In this study, a method is presented to decrease halogen compounds in the product oil from thermolysis of polystyrene and polypropylene mixed plastic spiked with tetrabromobisphenol A. A mixture of hydrotalcite and plastic was pyrolyzed in a glass reactor at 400 °C under a nitrogen atmosphere. Bromine compounds in the residual substances were measured. The yield of product oil increased using hydrotalcite as an additive. The bromine compounds that were the major ingredients in the oil after thermolysis at 400 °C from the mixed plastic, which also included toluene, ethyl benzene, styrene, and 1-methylethyl benzene, were 2-bromohexane, 3-bromo-1-propenyl benzene, 4,5-dibromodecane, 1-bromomethylbenzene, 3-bromophenol, and 4-bromo-2,6-dimethylbenzaniline. However, bromine compounds were not detected in the product oil, residue, or gas when hydrotalcite was added. After the thermolysis of the plastic, bromine compounds in the product oil may decrease because bromine was captured by the added hydrotalcite.

  8. Bromine and bromide content in soils: Analytical approach from total reflection X-ray fluorescence spectrometry.

    Science.gov (United States)

    Gallardo, Helena; Queralt, Ignasi; Tapias, Josefina; Candela, Lucila; Margui, Eva

    2016-08-01

    Monitoring total bromine and bromide concentrations in soils is significant in many environmental studies. Thus fast analytical methodologies that entail simple sample preparation and low-cost analyses are desired. In the present work, the possibilities and drawbacks of low-power total reflection X-ray fluorescence spectrometry (TXRF) for the determination of total bromine and bromide contents in soils were evaluated. The direct analysis of a solid suspension using 20 mg of fine ground soil (soils (Br content range in soils = 5-40 mg kg(-1)). Information about bromide determination in soils is also possible by analyzing the Br content in water soil extracts. In this case, the TXRF analysis can be directly performed by depositing 10 μL of the internal standardized soil extract sample on a quartz glass reflector in a measuring time of 1500 s. The bromide limit of detection by this approach was 10 μg L(-1). Good agreement was obtained between the TXRF results for the total bromine and bromide determinations in soils and those obtained by other popular analytical techniques, e.g. energy dispersive X-ray fluorescence spectrometry (total bromine) and ionic chromatography (bromide). As a study case, the TXRF method was applied to study bromine accumulation in two agricultural soils fumigated with a methyl bromide pesticide and irrigated with regenerated waste water. PMID:27179429

  9. Brominated Skeletal Components of the Marine Demosponges, Aplysina cavernicola and Ianthella basta: Analytical and Biochemical Investigations

    Directory of Open Access Journals (Sweden)

    Eike Brunner

    2013-04-01

    Full Text Available Demosponges possess a skeleton made of a composite material with various organic constituents and/or siliceous spicules. Chitin is an integral part of the skeleton of different sponges of the order Verongida. Moreover, sponges of the order Verongida, such as Aplysina cavernicola or Ianthella basta, are well-known for the biosynthesis of brominated tyrosine derivates, characteristic bioactive natural products. It has been unknown so far whether these compounds are exclusively present in the cellular matrix or whether they may also be incorporated into the chitin-based skeletons. In the present study, we therefore examined the skeletons of A. cavernicola and I. basta with respect to the presence of bromotyrosine metabolites. The chitin-based-skeletons isolated from these sponges indeed contain significant amounts of brominated compounds, which are not easily extractable from the skeletons by common solvents, such as MeOH, as shown by HPLC analyses in combination with NMR and IR spectroscopic measurements. Quantitative potentiometric analyses confirm that the skeleton-associated bromine mainly withstands the MeOH-based extraction. This observation suggests that the respective, but yet unidentified, brominated compounds are strongly bound to the sponge skeletons, possibly by covalent bonding. Moreover, gene fragments of halogenases suggested to be responsible for the incorporation of bromine into organic molecules could be amplified from DNA isolated from sponge samples enriched for sponge-associated bacteria.

  10. Characterization of unknown brominated disinfection byproducts during chlorination using ultrahigh resolution mass spectrometry.

    Science.gov (United States)

    Zhang, Haifeng; Zhang, Yahe; Shi, Quan; Zheng, Hongdie; Yang, Min

    2014-03-18

    Brominated disinfection byproducts (Br-DBPs), formed from the reaction of disinfectant(s) with natural organic matter in the presence of bromide in raw water, are generally more cytotoxic and genotoxic than their chlorinated analogues. To date, only a few Br-DBPs in drinking water have been identified, while a significant portion of Br-DBPs in drinking water is still unknown. In this study, negative ion electrospray ionization ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) was used to characterize unknown Br-DBPs in artificial drinking water. In total, 441 formulas for one-bromine-containing products and 37 formulas for two-bromine-containing products, most of which had not been previously reported, were detected in the chlorinated sample. Most Br-DBPs have corresponding chlorine-containing analogues with identical CHO composition. In addition, on-resonance collision-induced dissociation (CID) of single ultrahigh resolved bromine containing mass peaks was performed in the ICR cell to isolate single bromine-containing components in a very complex natural organic matter spectrum and provide structure information. Relatively abundant neutral loss of CO2 was observed in MS-MS spectra, indicating that the unknown Br-DBPs are rich in carboxyl groups. The results demonstrate that the ESI FT-ICR MS method could provide valuable molecular composition and structure information on unknown Br-DBPs.

  11. Removal efficiency of radioactive methyl iodide on TEDA-impregnated activated carbons

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Garcia, C.M.; Gonzalez, J.F.; Roman, S. [Extremadura Univ., Badajoz (Spain). Dept. de Fisica Aplicada

    2011-02-15

    Activated carbons were prepared by different series of carbon dioxide and steam activation from walnut shells for their optimal use as radioactive methyl iodide adsorbents in Nuclear Plants. The knowledge of the most favourable textural characteristics of the activated carbons was possible by the previous study of the commercial activated carbon currently used for this purpose. In order to increase their methyl iodide affinity, the effect of triethylenediamine impregnation was studied at 5 and 10 wt.%. The results obtained indicated that in both cases the adsorption efficiency is markedly improved by the addition of impregnant, which allows the adsorbate uptake to occur not only by physical adsorption, via non-specific interactions (as in non-impregnated carbons) but also by the specific interaction of triethylenediamine with radioactive methyl iodide. Methyl iodide retention efficiencies up to 98.1% were achieved. (author)

  12. Kinetics and mechanism of the mercury(II)-assisted hydrolysis of methyl iodide.

    Science.gov (United States)

    Celo, Valbona; Scott, Susannah L

    2005-04-01

    The kinetics and mechanism of the reaction of aqueous Hg(II) with methyl iodide have been investigated. The overall reaction is best described as Hg(II)-assisted hydrolysis, resulting in quantitative formation of methanol and, in the presence of excess methyl iodide, ultimately, HgI2 via the intermediate HgI+. The kinetics are biexponential when methyl iodide is in excess. At 25 degrees C, the acceleration provided by Hg2+ is 7.5 times greater than that caused by HgI+, while assistance of hydrolysis was not observed for HgI2. Thus, the reactions are not catalytic in Hg(II). The kinetics are consistent with an SN2-M+ mechanism involving electrophilic attack at iodide. As expected, methylation of mercury is not a reaction pathway; traces of methylmercury(II) are artifacts of the extraction/preconcentration procedure used for methylmercury analysis.

  13. Fluorescence characteristics of 5-amino salicylic acid: An iodide recognition study

    Science.gov (United States)

    Arora, Priyanka; Suyal, Kanchan; Joshi, Neeraj K.; Joshi, Hem Chandra; Pant, Sanjay

    In this paper we report the effect of iodide on the fluorescence of 5-amino salicylic acid (5-ASA). In the absence of iodide, prominent blue green (BG) emission band at ˜465 nm (broad) is observed in aprotic solvents whereas violet (V) emission at ˜408 nm, blue green (BG) at ˜480 nm and green (G) at ˜500 nm are observed in case of protic solvents. On the addition of iodide ion (I-), the intensity of BG fluorescence is enhanced in case of aprotic solvents. On the other hand the G band is enhanced in protic solvents and decrease in the intensity of the V band is observed. The effect of hydrogen bonding as well as the interplay of neutral and ionic species is invoked to explain the observed results. The study projects the application of this system in iodide recognition in protic/aprotic environments.

  14. A Direct Transformation of Aryl Aldehydes to Benzyl Iodides Via Reductive Iodination

    Energy Technology Data Exchange (ETDEWEB)

    Ruso, Jayaraman Sembian; Rajendiran, Nagappan; Kumaran, Rajendran Senthil [Univ. of Madras, Chennai (India)

    2014-02-15

    A facile transformation of aryl aldehydes to benzyl iodides through one-pot reductive iodination is reported. This protocol displays remarkable functional group tolerance and the title compound was obtained in good to excellent yield.

  15. Horseradish Peroxidase-Mediated, Iodide-Catalyzed Cascade Reaction for Plasmonic Immunoassays.

    Science.gov (United States)

    Xianyu, Yunlei; Chen, Yiping; Jiang, Xingyu

    2015-11-01

    This report outlines an enzymatic cascade reaction for signal transduction and amplification for plasmonic immunoassays by using horseradish peroxidase (HRP)-mediated aggregation of gold nanoparticles (AuNPs). HRP-catalyzed oxidation of iodide and iodide-catalyzed oxidation of cysteine is employed to modulate the plasmonic signals of AuNPs. It agrees well with the current immunoassay platforms and allows naked-eye readout with enhanced sensitivity, which holds great promise for applications in resource-constrained settings.

  16. Polarization Effects in Methylammonium Lead Iodide Electronic Devices

    Science.gov (United States)

    Labram, John; Fabini, Douglas; Perry, Erin; Lehner, Anna; Wang, Hengbin; Glaudell, Anne; Wu, Guang; Evans, Hayden; Buck, David; Cotta, Robert; Echegoyen, Luis; Wudl, Fred; Seshadri, Ram; Chabinyc, Michael

    The immense success of group IV and III-V semiconductors has resulted in disruptive new photovoltaic (PV) cell technologies emerging extremely infrequently. For this reason, the recent progress in Methylammonium Lead Iodide (MAPbI3) solar cells can be viewed as a highly significant historic event. Despite the staggering recent progress made in reported power conversion efficiency (PCE), debate remains intense on the nature of the various instabilities synonymous with these devices. Using various electronic device measurements, we here present a body of experimental evidence consistent with the existence of a mobile ionic species within the MAPbI3 perovskite. Temperature-dependent transistor measurements reveal operating FET devices only below approximately 210K. This is attributed to ionic screening of the (otherwise charge-neutral) semiconductor-dielectric interface. Temperature-dependent pulsed-gate and impedance spectroscopy experiments also reveal behavior consistent with this interpretation. MAPbI3 PV cells were found to possess a PCE which decreases significantly below 210K. Combined, these set of measurements provide an interesting and consistent description of the internal processes at play within the MAPbI3 perovskite structure.

  17. Thermopower and activation energy of silver iodide based superionic materials

    International Nuclear Information System (INIS)

    Silver iodide based glasses, 60Agl-20Ag sub 2 O-20B sub 2O sub 3, 6 Agl-20Ag sub 2 O-20 MoO sub 3 and 60Agl-20Ag sub 2O-20WO sub 3, all in the mol % ratio, were prepared by rapidly quenching the melts of the chemicals in a stainless steel container; kept in a liquid nitrogen bath. The glassy nature of the as-quenched materials was confirmed by X-ray diffraction (XRD). The electrical conductivity of the glasses was measured at various temperatures ranging from 30 to 70 degree C using an impedance bridge operating in the frequency range between 40 Hz to 100 kHz. The plot of In σT versus 1000/T for each glassy material obeys Arrhenius law and the activation energy obtained is between 0.2 to 0.3 eV. Thermopower measurement was also carried out in the same temperature range as the conductivity measurement to obtain the heat of transport

  18. Chloride, bromide and iodide scintillators with europium doping

    Science.gov (United States)

    Zhuravleva, Mariya; Yang, Kan

    2014-08-26

    A halide scintillator material is disclosed where the halide may comprise chloride, bromide or iodide. The material is single-crystalline and has a composition of the general formula ABX.sub.3 where A is an alkali, B is an alkali earth and X is a halide which general composition was investigated. In particular, crystals of the formula ACa.sub.1-yEu.sub.yI.sub.3 where A=K, Rb and Cs were formed as well as crystals of the formula CsA.sub.1-yEu.sub.yX.sub.3 (where A=Ca, Sr, Ba, or a combination thereof and X=Cl, Br or I or a combination thereof) with divalent Europium doping where 0.ltoreq.y.ltoreq.1, and more particularly Eu doping has been studied at one to ten mol %. The disclosed scintillator materials are suitable for making scintillation detectors used in applications such as medical imaging and homeland security.

  19. Digermylene Oxide Stabilized Group 11 Metal Iodide Complexes.

    Science.gov (United States)

    Yadav, Dhirendra; Siwatch, Rahul Kumar; Sinhababu, Soumen; Karwasara, Surendar; Singh, Dharmendra; Rajaraman, Gopalan; Nagendran, Selvarajan

    2015-12-01

    Use of a substituted digermylene oxide as a ligand has been demonstrated through the isolation of a series of group 11 metal(I) iodide complexes. Accordingly, the reactions of digermylene oxide [{(i-Bu)2ATIGe}2O] (ATI = aminotroponiminate) (1) with CuI under different conditions afforded [({(i-Bu)2ATIGe}2O)2(Cu4I4)] (2) with a Cu4I4 octahedral core, [({(i-Bu)2ATIGe}2O)2(Cu3I3)] (3) with a Cu3I3 core, and [{(i-Bu)2ATIGe}2O(Cu2I2)(C5H5N)2] (4) with a butterfly-type Cu2I2 core. The reactions of compound 1 with AgI and AuI produced [({(i-Bu)2ATIGe}2O)2(Ag4I4)] (5) with a Ag4I4 octahedral core and [{(i-Bu)2ATIGe}2O(Au2I2)] (6) with a Au2I2 core, respectively. The presence of metallophilic interactions in these compounds is shown through the single-crystal X-ray diffraction and atom-in-molecule (AIM) studies. Preliminary photophysical studies on compound 6 are also carried out. PMID:26558406

  20. Persistent photovoltage in methylammonium lead iodide perovskite solar cells

    Directory of Open Access Journals (Sweden)

    A. Baumann

    2014-08-01

    Full Text Available We herein perform open circuit voltage decay (OCVD measurements on methylammonium lead iodide (CH3NH3PbI3 perovskite solar cells to increase the understanding of the charge carrier recombination dynamics in this emerging technology. Optically pulsed OCVD measurements are conducted on CH3NH3PbI3 solar cells and compared to results from another type of thin-film photovoltaics, namely, the two reference polymer–fullerene bulk heterojunction solar cell devices based on P3HT:PC60BM and PTB7:PC70BM blends. We observe two very different time domains of the voltage transient in the perovskite solar cell with a first drop on a short time scale that is similar to the decay in the studied organic solar cells. However, 65%–70% of the maximum photovoltage persists on much longer timescales in the perovskite solar cell than in the organic devices. In addition, we find that the recombination dynamics in all time regimes are dependent on the starting illumination intensity, which is also not observed in the organic devices. We then discuss the potential origins of these unique behaviors.

  1. Lead iodide X-ray and gamma-ray spectrometers for room and high temperature operation

    Energy Technology Data Exchange (ETDEWEB)

    Hermon, H.; James, R.B.; Cross, E. [and others

    1997-02-01

    In this study, we report on the results of the investigation of lead iodide material properties. The effectiveness of zone refining purification methods on the material purity is determined by ICP-MS and ICP-OES and correlated to the electrical and physical material properties. We show that this zone refining method is very efficient in removing impurities from lead iodide and we also determine the segregation coefficient for some of these impurities. Triple axis x- ray diffraction (TAD) analysis has been used to determine the crystalline perfection of the lead iodide after applying various cutting, etching, and fabrication methods. The soft lead iodide crystal was found to be damaged when cleaved by a razor blade, but by using a diamond wheel saw, followed by etching, the crystallinity of the material was improved, as observed by TAD. Low temperature photoluminescence also indicates an improvement in the material properties of the purified lead iodide. Electrical properties of lead iodide such as carrier mobility, were calculated based on carrier- phonon scattering. The results for the electrical properties were in good agreement with the experimental data.

  2. Critical Evaluation of Acetylthiocholine Iodide and Acetylthiocholine Chloride as Substrates for Amperometric Biosensors Based on Acetylcholinesterase

    Directory of Open Access Journals (Sweden)

    Gabriel-Lucian Radu

    2013-01-01

    Full Text Available Numerous amperometric biosensors have been developed for the fast analysis of neurotoxic insecticides based on inhibition of cholinesterase (AChE. The analytical signal is quantified by the oxidation of the thiocholine that is produced enzymatically by the hydrolysis of the acetylthiocholine pseudosubstrate. The pseudosubstrate is a cation and it is associated with chloride or iodide as corresponding anion to form a salt. The iodide salt is cheaper, but it is electrochemically active and consequently more difficult to use in electrochemical analytical devices. We investigate the possibility of using acetylthiocholine iodide as pseudosubstrate for amperometric detection. Our investigation demonstrates that operational conditions for any amperometric biosensor that use acetylthiocholine iodide must be thoroughly optimized to avoid false analytical signals or a reduced sensitivity. The working overpotential determined for different screen-printed electrodes was: carbon-nanotubes (360 mV, platinum (560 mV, gold (370 mV, based on a catalytic effect of iodide or cobalt phthalocyanine (110 mV, but with a significant reduced sensitivity in the presence of iodide anions.

  3. Experimental study of retinoic acid on improving iodide uptake in MCF-7 breast cancer cells

    Institute of Scientific and Technical Information of China (English)

    FU Hong-Liang; WU Jing-Chuan; DU Xue-Liang; LI Jia-Ning; WU Zhen; ZOU Ren-Jian

    2005-01-01

    The study aims to investigate the effect of retinoic acid on the iodide uptake of MCF-7 cells and its mechanism. The iodide uptake and expression of hNIS(human sodium/iodide symporter)mRNA in the breast cancer MCF-7 cells were compared individually before and after the intervention of all-trans retinoic acid (ATRA) with the iodide uptake assay and RT-PCR. The following results are obtained: (1) when treated with all-trans retinoic acid in the concentration of 1.0 μmol/L, the capacity of iodide uptake of MCF-7 cells reached about 1.5 times of the basal state; (2) 12 h after the intervention of 1.0 μmol/L ATRA, the hNISmRNA expression of the MCF-7 cells reached maximum. The study shows that all-trans retinoic acid has the effect to improve the iodide uptake of the MCF-7 cells and this effect may result from its up-regulation of the hNISmRNA expression.

  4. Modelling iodide – iodate speciation in atmospheric aerosol: Contributions of inorganic and organic iodine chemistry

    Directory of Open Access Journals (Sweden)

    S. Pechtl

    2007-01-01

    Full Text Available The speciation of iodine in atmospheric aerosol is currently poorly understood. Models predict negligible iodide concentrations but accumulation of iodate in aerosol, both of which is not confirmed by recent measurements. We present an updated aqueous phase iodine chemistry scheme for use in atmospheric chemistry models and discuss sensitivity studies with the marine boundary layer model MISTRA. These studies show that iodate can be reduced in acidic aerosol by inorganic reactions, i.e., iodate does not necessarily accumulate in particles. Furthermore, the transformation of particulate iodide to volatile iodine species likely has been overestimated in previous model studies due to negligence of collision-induced upper limits for the reaction rates. However, inorganic reaction cycles still do not seem to be sufficient to reproduce the observed range of iodide – iodate speciation in atmospheric aerosol. Therefore, we also investigate the effects of the recently suggested reaction of HOI with dissolved organic matter to produce iodide. If this reaction is fast enough to compete with the inorganic mechanism, it would not only directly lead to enhanced iodide concentrations but, indirectly via speed-up of the inorganic iodate reduction cycles, also to a decrease in iodate concentrations. Hence, according to our model studies, organic iodine chemistry, combined with inorganic reaction cycles, is able to reproduce observations. The presented chemistry cycles are highly dependent on pH and thus offer an explanation for the large observed variability of the iodide – iodate speciation in atmospheric aerosol.

  5. A selective iodide ion sensor electrode based on functionalized ZnO nanotubes.

    Science.gov (United States)

    Ibupoto, Zafar Hussain; Khun, Kimleang; Willander, Magnus

    2013-01-01

    In this research work, ZnO nanotubes were fabricated on a gold coated glass substrate through chemical etching by the aqueous chemical growth method. For the first time a nanostructure-based iodide ion selective electrode was developed. The ZnO nanotubes were functionalized with miconazole ion exchanger and the electromotive force (EMF) was measured by the potentiometric method. The iodide ion sensor exhibited a linear response over a wide range of concentrations (1 × 10-6 to 1 × 10-1 M) and excellent sensitivity of -62 ± 1 mV/decade. The detection limit of the proposed sensor was found to be 5 × 10-7 M. The effects of pH, temperature, additive, plasticizer and stabilizer on the potential response of iodide ion selective electrode were also studied. The proposed iodide ion sensor demonstrated a fast response time of less than 5 s and high selectivity against common organic and the inorganic anions. All the obtained results revealed that the iodide ion sensor based on functionalized ZnO nanotubes may be used for the detection of iodide ion in environmental water samples, pharmaceutical products and other real samples. PMID:23385412

  6. A Selective Iodide Ion Sensor Electrode Based on Functionalized ZnO Nanotubes

    Directory of Open Access Journals (Sweden)

    Magnus Willander

    2013-02-01

    Full Text Available In this research work, ZnO nanotubes were fabricated on a gold coated glass substrate through chemical etching by the aqueous chemical growth method. For the first time a nanostructure-based iodide ion selective electrode was developed. The ZnO nanotubes were functionalized with miconazole ion exchanger and the electromotive force (EMF was measured by the potentiometric method. The iodide ion sensor exhibited a linear response over a wide range of concentrations (1 × 10−6 to 1 × 10−1 M and excellent sensitivity of –62 ± 1 mV/decade. The detection limit of the proposed sensor was found to be 5 × 10−7 M. The effects of pH, temperature, additive, plasticizer and stabilizer on the potential response of iodide ion selective electrode were also studied. The proposed iodide ion sensor demonstrated a fast response time of less than 5 s and high selectivity against common organic and the inorganic anions. All the obtained results revealed that the iodide ion sensor based on functionalized ZnO nanotubes may be used for the detection of iodide ion in environmental water samples, pharmaceutical products and other real samples.

  7. The effect of elemental and hydrocarbon impurities on mercuric iodide gamma ray detector performance

    Science.gov (United States)

    Cross, Eilene S.; Buffleben, George; Soria, Ed; James, Ralph; Schieber, Michael; Natarajan, Raj; Gerrish, Vern

    Mercuric iodide is a room temperature semiconductor material that is used for gamma ray and x-ray radiation detection. Mercuric iodide is synthesized from mercuric chloride and potassium iodide and is then purified by a series of melts and sublimation steps and by zone refining. The mercuric iodide is grown into crystals and platelets and then fabricated into detectors. Elemental contamination may be a determining factor in the performance of these detectors. These contaminates may be present in the starting material or may be introduced during, or be unaffected by, the purification, growth or fabrication steps. Methods have been developed for the analysis of trace levels of elemental contamination. Inductively Coupled Plasma/Mass Spectroscopy (ICP/MS), Inductively Coupled Plasma/Optical Emission Spectroscopy (ICP/OES) and Gas Chromatography/Mass Spectroscopy (GC/MS) are used to determine sub ppm levels of many trace elemental impurities. Trace levels of many elemental impurities in the raw mercuric iodide are significantly reduced during the purification and zone refining processes. Though the levels of impurities are reduced, poor performing mercuric iodide detectors have contamination levels remaining or reintroduced which are higher for Ag, Al, Ca, Cu, Mg, Mn, Na, Pb and Zn than detectors with good gamma ray response. This paper will discuss the analytical methodology, the effects of purification on impurity levels, and the correlation between detector performance and impurity levels.

  8. The NBS Reaction: A Simple Explanation for the Predominance of Allylic Substitution over Olefin Addition by Bromine at Low Concentrations.

    Science.gov (United States)

    Wamser, Carl C.; Scott, Lawrence T.

    1985-01-01

    Examines mechanisms related to use of N-bromosuccinimide (NBS) for bromination at an allylic position. Also presents derived rate laws for three possible reactions of molecular bromine with an alkene: (1) free radical substitution; (2) free radical addition; and (3) electrophilic addition. (JN)

  9. Determination of bromine contents in blood and hair of workers exposed to methyl by radioactivation analysis method bromide

    International Nuclear Information System (INIS)

    The bromine contained in blood and hair samples obtained from workers exposed to methyl bromide was analyzed by nondestructive activation analysis. The samples were irradiated for 1 min in pneumatic irradiation facility of Kyoto University research reactor with an estimated thermal neutron flux density at 2 x 1013 n.cm-2.sec-1. The irradiation was counted with Ge(Li) detector. The duration of measurement of radionuclide bromine in blood and hair was 200 sec within 2 - 10 min after irradiation. The bromine content of serum sample obtained from a worker suspected of methyl bromide poisoning was found to be 412 μg/g on 13 days apart from exposure to methyl bromide. The biological half-life of bromine in this case was found to be about 16 days. Then bromine contents in serum and hair samples obtained from workers exposed to methyl bromide were found to be 1.7 and 2.6 times higher respectively than those of nonexposed workers. Any correlations of bromine contents were not observed between serum and hair samples obtained from workers exposed to methyl bromide, nor between bromine amount in the serum of workers exposed to methyl bromide and the terms exposed to it, but statistically significant positive correlation was observed between bromine amount in the hair of workers exposed to methyl bromide and the terms exposed to it. (author)

  10. Bromination of Marine Dissolved Organic Matter following Full Scale Electrochemical Ballast Water Disinfection.

    Science.gov (United States)

    Gonsior, Michael; Mitchelmore, Carys; Heyes, Andrew; Harir, Mourad; Richardson, Susan D; Petty, William Tyler; Wright, David A; Schmitt-Kopplin, Philippe

    2015-08-01

    An extensively diverse array of brominated disinfection byproducts (DBPs) were generated following electrochemical disinfection of natural coastal/estuarine water, which is one of the main treatment methods currently under consideration for ballast water treatment. Ultra-high-resolution mass spectrometry revealed 462 distinct brominated DBPs at a relative abundance in the mass spectra of more than 1%. A brominated DBP with a relative abundance of almost 22% was identified as 2,2,4-tribromo-5-hydroxy-4-cyclopentene-1,3-dione, which is an analogue to several previously described 2,2,4-trihalo-5-hydroxy-4-cyclopentene-1,3-diones in drinking water. Several other brominated molecular formulas matched those of other known brominated DBPs, such as dibromomethane, which could be generated by decarboxylation of dibromoacetic acid during ionization, dibromophenol, dibromopropanoic acid, dibromobutanoic acid, bromohydroxybenzoic acid, bromophenylacetic acid, bromooxopentenoic acid, and dibromopentenedioic acid. Via comparison to previously described chlorine-containing analogues, bromophenylacetic acid, dibromooxopentenoic acid, and dibromopentenedioic acid were also identified. A novel compound at a 4% relative abundance was identified as tribromoethenesulfonate. This compound has not been previously described as a DBP, and its core structure of tribromoethene has been demonstrated to show toxicological implications. Here we show that electrochemical disinfection, suggested as a candidate for successful ballast water treatment, caused considerable production of some previously characterized DBPs in addition to novel brominated DBPs, although several hundred compounds remain structurally uncharacterized. Our results clearly demonstrate that electrochemical and potentially direct chlorination of ballast water in estuarine and marine systems should be approached with caution and the concentrations, fate, and toxicity of DBP need to be further characterized.

  11. Photochemical bromination of substituted indan-1-one derivatives: synthesis of new polybromoindan-1-one derivatives

    OpenAIRE

    KUŞ, Nermin Şimşek

    2009-01-01

    The photobromination of substituted indan derivatives was studied. Four products, 2,3-dibromo-inden-1-one (5), trans-2,3-dibromoindan-1-one (6), 2,2-dibromoindan-1,3-dione (7) and 2,2-dibromoindan-1-one (8), were obtained by the bromination of indan-1-one (4). The bromination of 2-methyl indanone (9) and 3-methyl-indanone (13) gave the corresponding monobromo, dibromo, and tribromo compounds in high yield. 4-Nitro indan (16) was tribrominated under same condition reaction. The stru...

  12. Effect of Brominated Furanones on the Formation of Biofilm by Escherichia coli on Polyvinyl Chloride Materials

    OpenAIRE

    Lianhua, Ye; Yunchao, Huang; Geng, Xu; Youquang, Zhou; Guangqiang, Zhao; Yujie, Lei

    2013-01-01

    To study the influence of brominated furanones on the biofilm (BF) formation by Escherichia coli (E. coli) on polyvinyl chloride (PVC) material, and to provide new ways of surface modification of materials to clinically prevent biomaterial centered infection. Three brominated furanones, dissolved in ethanol, furanone-1(3,4-dibromo-5-hydroxyl-furanone), furanone-2(4-bromo-5-(4-methoxypheny)-3-(methylamino)-furanone), and furanone-3(3,4-dibromo-5,5-dimethoxypheny-2(5H)-furanone) with representa...

  13. A glucose bio-battery prototype based on a GDH/poly(methylene blue) bioanode and a graphite cathode with an iodide/tri-iodide redox couple.

    Science.gov (United States)

    Wang, Jen-Yuan; Nien, Po-Chin; Chen, Chien-Hsiao; Chen, Lin-Chi; Ho, Kuo-Chuan

    2012-07-01

    A glucose bio-battery prototype independent of oxygen is proposed based on a glucose dehydrogenase (GDH) bioanode and a graphite cathode with an iodide/tri-iodide redox couple. At the bioanode, a NADH electrocatalyst, poly(methylene blue) (PMB), which can be easily grown on the electrode (screen-printed carbon paste electrode, SPCE) by electrodeposition, is harnessed and engineered. We find that carboxylated multi-walled carbon nanotubes (MWCNTs) are capable of significantly increasing the deposition amount of PMB and thus enhancing the PMB's electrocatalysis of NADH oxidation and the glucose bio-battery's performance. The choice of the iodide/tri-iodide redox couple eliminates the dependence of oxygen for this bio-battery, thus enabling the bio-battery with a constant current-output feature similar to that of the solar cells. The present glucose bio-battery prototype can attain a maximum power density of 2.4 μW/cm(2) at 25 °C. PMID:22541949

  14. Characterization of strontium iodide scintillators with silicon photomultipliers

    Science.gov (United States)

    Mitchell, Lee J.; Phlips, Bernard

    2016-06-01

    This work characterizes a commercially available europium-doped strontium iodide detector recently developed by Radiation Monitoring Devices (RMD). The detector has been chosen for a space-based mission scheduled to launch in early 2017. The primary goal of this work was to characterize the detector's response over the expected operational range of -10 °C to 30 °C as well as the expected operational voltage range of +26.5-+28.5 V and identify background interferences that may develop due to neutron activation produced by cosmic-ray interactions. The 8 mm×8 mm×20 mm detectors use KETEK silicon photomultipliers (SiPM), with an active area of 6 mmx6 mm (KETEK PM6660). Our results show substantial integral nonlinearity due to the SiPM ranging from 0% to 25% at room temperature over the energy range of 80-2614 keV. The nonlinearity, a function of temperature and overvoltage, leads to an underestimate of the full width at half max (FWHM), which is 2.6% uncorrected at 662 keV and 3.8% corrected at 662 keV. The temperature dependence of the detector results in a noise threshold that increases substantially above 30 °C due to the SiPM dark rate. In an effort to simulate the harsh environment of space, neutron activation of the detector was also explored. Gamma-ray lines at 127 keV and 164 keV were observed in the detector along with Kα x-rays associated with europium. Beta decay from europium- and iodine-activation products were also observed within the detector.

  15. THERAPY OF GRAVES’ DISEASE WITH SODIUM IODIDE-131

    Directory of Open Access Journals (Sweden)

    I Wayan Hartadi Noor

    2013-11-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 Graves’ disease is the most common form of thyrotoxicosis, with a peak incidence in the 20-40 year of age group. Females are involved about five times more commonly than male. The easiest sign to recognize patients with Graves’ disease is the present of Graves’ ophthalmopathy. The diagnosis of Graves’ disease may sometimes base only on a physical examination and a medical history. Diffuse thyroid enlargement and sign of thyrotoxicosis, mainly ophthalmopathy and to lesser extent dermopathy, usually adequate for diagnosis. TSH test combined with FT4 test is usually the first laboratory test performs in these patients. The patients suffered Graves’ disease can be treated with antithyroid drug therapy or undergo subtotal Thyroidectomy. Another therapy is by using sodium iodide-131, where this therapy has advantages including easy administration, effectiveness, low expense, and absence of pain. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;}

  16. Imaging with polycrystalline mercuric iodide detectors using VLSI readout

    Energy Technology Data Exchange (ETDEWEB)

    Turchetta, R.; Dulinski, W.; Husson, D.; Riester, J.L.; Schieber, M.; Zuck, A.; Melekhov, L.; Saado, Y.; Hermon, H.; Nissenbaum, J

    1999-06-01

    Potentially low cost and large area polycrystalline mercuric iodide room-temperature radiation detectors, with thickness of 100-600 {mu}m have been successfully tested with dedicated low-noise, low-power mixed signal VLSI electronics which can be used for compact, imaging solutions. The detectors are fabricated by depositing HgI{sub 2} directly on an insulating substrate having electrodes in the form of microstrips and pixels with an upper continuous electrode. The deposition is made either by direct evaporation or by screen printing HgI{sub 2} mixed with glue such as Poly-Vinyl-Butiral. The properties of these first-generation detectors are quite uniform from one detector to another. Also for each single detector the response is quite uniform and no charge loss in the inter-electrode space have been detected. Because of the low cost and of the polycrystallinity, detectors can be potentially fabricated in any size and shape, using standard ceramic technology equipment, which is an attractive feature where low cost and large area applications are needed. The detectors which act as radiation counters have been tested with a beta source as well as in a high-energy beam of 100 GeV muons at CERN, connected to VLSI, low noise electronics. Charge collection efficiency and uniformity have been studied. The charge is efficiently collected even in the space between strips indicating that fill factors of 100% could be reached in imaging applications with direct detection of radiation. Single photon counting capability is reached with VLSI electronics. These results show the potential of this material for applications demanding position sensitive, radiation resistant, room-temperature operating radiation detectors, where position resolution is essential, as it can be found in some applications in high-energy physics, nuclear medicine and astrophysics.

  17. Retinoic acid induces sodium/iodide symporter gene expression and radioiodide uptake in the MCF-7 breast cancer cell line

    OpenAIRE

    Kogai, Takahiko; Schultz, James J.; Johnson, Laura S.; Huang, Min; Brent, Gregory A.

    2000-01-01

    The sodium/iodide symporter (NIS) stimulates iodide uptake in normal lactating breast, but is not known to be active in nonlactating breast or breast cancer. We studied NIS gene regulation and iodide uptake in MCF-7 cells, an estrogen receptor (ER)-positive human breast cancer cell line. All-trans retinoic acid (tRA) treatment stimulated iodide uptake in a time- and dose-dependent fashion up to ≈9.4-fold above baseline. Stimulation with selective retinoid compounds indicated that the inductio...

  18. Development of crystals based in cesium iodide for application as radiation detectors; Desenvolvimento de cristais baseados em iodeto de cesio para aplicacao como detectores de radiacao

    Energy Technology Data Exchange (ETDEWEB)

    Pereira, Maria da Conceicao Costa

    2006-07-01

    Inorganic scintillators with fast luminescence decay time, high density and high light output have been the object of studies for application in nuclear physics, high energy physics, nuclear tomography and other fields of science and engineering. Scintillation crystals based on cesium iodide (CsI) are matters with relatively low higroscopy, high atomic number, easy handling and low cost, characteristics that favor their use as radiation detectors. In this work, the growth of pure CsI crystals, CsI:Br and CsI:Pb, using the Bridgman technique, is described. The concentration of the bromine doping element (Br) was studied in the range of 1,5x10{sup -1} M to 10{sup -2} M and the lead (Pb) in the range of 10{sup -2} M to 5x10{sup -4} M. To evaluate the scintillators developed, systematic measurements were carried out for luminescence emission and luminescence decay time for gamma radiation, optical transmittance assays, Vickers micro-hardness assays, determination of the doping elements distribution along the grown crystals and analysis of crystals response to the gamma radiation in the energy range of 350 keV to 1330 keV and alpha particles from a {sup 241}Am source, with energy of 5.54 MeV. It was obtained 13 ns to 19 ns for luminescence decay time for CsI:Br and CsI:Pb crystals. These results were very promising. The results obtained for micro-hardness showed a significant increase in function of the doping elements concentration, when compared to the pure CsI crystal, increasing consequently the mechanical resistance of the grown crystals. The validity of using these crystals as radiation sensors may be seen from the results of their response to gamma radiation and alpha particles. (author)

  19. Performance and Degradation of A Lithium-Bromine Rechargeable Fuel Cell Using Highly Concentrated Catholytes

    CERN Document Server

    Bai, Peng

    2016-01-01

    Lithium-air batteries have been considered as ultimate solutions for the power source of long-range electrified transportation, but state-of-the-art prototypes still suffer from short cycle life, low efficiency and poor power output. Here, a lithium-bromine rechargeable fuel cell using highly concentrated bromine catholytes is demonstrated with comparable specific energy, improved power density, and higher efficiency. The cell is similar in structure to a hybrid-electrolyte Li-air battery, where a lithium metal anode in nonaqueous electrolyte is separated from aqueous bromine catholytes by a lithium-ion conducting ceramic plate. The cell with a flat graphite electrode can discharge at a peak power density around 9mW cm-2 and in principle could provide a specific energy of 791.8 Wh kg-1, superior to most existing cathode materials and catholytes. It can also run in regenerative mode to recover the lithium metal anode and free bromine with 80-90% voltage efficiency, without any catalysts. Degradation of the sol...

  20. Bromine partitioning in the tropical tropopause layer: implications for stratospheric injection

    Directory of Open Access Journals (Sweden)

    R. P. Fernandez

    2014-07-01

    Full Text Available Very short-lived (VSL bromocarbons are produced at a prodigious rate by ocean biology and these source compounds (SGVSL, together with their degradation inorganic products (PGVSL, are lofted by vigorous convection to the tropical tropopause layer (TTL. Using a state-of-the-art photochemical mechanism within a global model, we calculate annual average stratospheric injection of total bromine due to VSL sources to be 5 pptv, with ~3 pptv entering the stratosphere as PGVSL and ~2 pptv as SGVSL. The geographic distribution and partitioning of VSL bromine within the TTL, and its consequent stratospheric injection, is highly dependent on the oceanic flux, the strength of convection and the occurrence of heterogeneous recycling reactions. Our calculations indicate atomic Br should be the dominant inorganic species in large regions of the TTL during daytime, due to the low ozone and cold conditions of this region. We propose the existence of a "tropical ring of atomic bromine" located approximately between 15 and 19 km and 30° N to 30° S. Daytime Br / BrO ratios of up to ~4 are predicted within the Br ring in regions of highly convective transport, such as the tropical Western Pacific. Then, we suggest experimental programs designed to quantify the bromine budget of the TTL and the stratospheric injection of VSL biogenic bromocarbons should include a strategy for the measurement of atomic Br during daytime and HOBr or BrCl during nighttime.

  1. Regioselective chlorination and bromination of unprotected anilines under mild conditions using copper halides in ionic liquids

    OpenAIRE

    Han Wang; Kun Wen; Nurbiya Nurahmat; Yan Shao; He Zhang; Chao Wei; Ya Li; Yongjia Shen; Zhihua Sun

    2012-01-01

    By using ionic liquids as solvents, the chlorination or bromination of unprotected anilines at the para-position can be achieved in high yields with copper halides under mild conditions, without the need for potentially hazardous operations such as supplementing oxygen or gaseous HCl.

  2. Regioselective chlorination and bromination of unprotected anilines under mild conditions using copper halides in ionic liquids

    Directory of Open Access Journals (Sweden)

    Han Wang

    2012-05-01

    Full Text Available By using ionic liquids as solvents, the chlorination or bromination of unprotected anilines at the para-position can be achieved in high yields with copper halides under mild conditions, without the need for potentially hazardous operations such as supplementing oxygen or gaseous HCl.

  3. Microbial degradation of the brominated flame retardant TBNPA by groundwater bacteria: laboratory and field study.

    Science.gov (United States)

    Balaban, Noa; Bernstein, Anat; Gelman, Faina; Ronen, Zeev

    2016-08-01

    In the present study, the biodegradation of the brominated flame retardant tribromoneopentylalcohol (TBNPA) by a groundwater enrichment culture was investigated using a dual carbon ((13)C/(12)C)- bromine ((81)Br/(79)Br) stable isotope analysis. An indigenous aerobic bacterial consortium was enriched from the polluted groundwater underlying an industrial site in the northern Negev Desert, Israel, where TBNPA is an abundant pollutant. Aerobic biodegradation was shown to be rapid, with complete debromination within a few days, whereas anaerobic biodegradation was not observed. Biodegradation under aerobic conditions was accompanied by a significant carbon isotope effect with an isotopic enrichment factor of ɛCbulk = -8.8‰ ± 1.5‰, without any detectable bromine isotope fractionation. It was found that molecular oxygen is necessary for biodegradation to occur, suggesting an initial oxidative step. Based on these results, it was proposed that H abstraction from the C-H bond is the first step of TBNPA biodegradation under aerobic conditions, and that the C-H bond cleavage results in the formation of unstable intermediates, which are rapidly debrominated. A preliminary isotopic analysis of TBNPA in the groundwater underlying the industrial area revealed that there are no changes in the carbon and bromine isotope ratio values downstream of the contamination source. Considering that anoxic conditions prevail in the groundwater of the contaminated site, the lack of isotope shifts in TBNPA indicates the lack of TBNPA biodegradation in the groundwater, in accordance with our findings. PMID:27183339

  4. METABOLISM OF BROMINATED FLAME RETARDANTS IN HUMAN ASTROCYTES AND EFFECTS ON THYROID HORMONE HOMEOSTASIS

    Science.gov (United States)

    In this proposed study, hydroxylated PBDEs and brominated phenols likely will be formed in astrocytes as a result of cytochrome p450-mediated metabolism. Previous studies have shown that polychlorinated biphenyls (PCBs) affect the regulation of thyroid hormones at the bloo...

  5. Photothermally induced bromination of carbon/polymer bipolar plate materials for fuel cell applications

    Science.gov (United States)

    Schade, Martin; Franzka, Steffen; Cappuccio, Franco; Peinecke, Volker; Heinzel, Angelika; Hartmann, Nils

    2015-05-01

    A facile photothermal procedure for direct functionalization of carbon/polymer bipolar plate materials is demonstrated. Through irradiation with a microfocused beam of an Ar+-laser at λ = 514 nm in gaseous bromine and distinct laser powers and pulse lengths local bromination of the carbon/polymer material takes place. At a 1/e spot diameter of 2.1 μm, functionalized surface areas with diameters down to 5 μm are fabricated. In complementary experiments large-area bromination is investigated using an ordinary tungsten lamp. For characterization contact angle goniometry, X-ray photoelectron spectroscopy and electron microscopy in conjunction with labeling techniques are employed. After irradiation bromine groups can easily be substituted by other chemical functionalities, e.g. azide and amine groups. This provides a facile approach in order to fabricate surface patterns and gradient structures with varying wetting characteristics. Mechanistic aspects and prospects of photothermal routines in micropatterning of carbon/polymer materials are discussed.

  6. XAS AND XPS CHARACTERIZATION OF MERCURY BINDING ON BROMINATED ACTIVATED CARBON

    Science.gov (United States)

    Brominated powdered activated carbon sorbents have been shown to e quite effective for mercury capture when injected into the flue gas duct at coal-fired power plants and are especially useful when buring Western low-chlorine subbituminous coals. X-ray absorption spectroscopy (X...

  7. On the bromination of the dihydroazulene/vinylheptafulvene photo-/thermoswitch

    DEFF Research Database (Denmark)

    Mazzanti, Virginia; Cacciarini, Martina; Broman, Søren Lindbæk;

    2012-01-01

    Background: The dihydroazulene (DHA)/vinylheptafulvene (VHF) system (with two cyano groups at C1) functions as a photo-/thermoswitch. Direct ionic bromination of DHA has previously furnished a regioselective route to a 7,8-dibromide, which by elimination was converted to a 7-bromo-substituted DHA...

  8. Canadian Arctic sea ice reconstructed from bromine in the Greenland NEEM ice core.

    Science.gov (United States)

    Spolaor, Andrea; Vallelonga, Paul; Turetta, Clara; Maffezzoli, Niccolò; Cozzi, Giulio; Gabrieli, Jacopo; Barbante, Carlo; Goto-Azuma, Kumiko; Saiz-Lopez, Alfonso; Cuevas, Carlos A; Dahl-Jensen, Dorthe

    2016-09-21

    Reconstructing the past variability of Arctic sea ice provides an essential context for recent multi-year sea ice decline, although few quantitative reconstructions cover the Holocene period prior to the earliest historical records 1,200 years ago. Photochemical recycling of bromine is observed over first-year, or seasonal, sea ice in so-called "bromine explosions" and we employ a 1-D chemistry transport model to quantify processes of bromine enrichment over first-year sea ice and depositional transport over multi-year sea ice and land ice. We report bromine enrichment in the Northwest Greenland Eemian NEEM ice core since the end of the Eemian interglacial 120,000 years ago, finding the maximum extension of first-year sea ice occurred approximately 9,000 years ago during the Holocene climate optimum, when Greenland temperatures were 2 to 3 °C above present values. First-year sea ice extent was lowest during the glacial stadials suggesting complete coverage of the Arctic Ocean by multi-year sea ice. These findings demonstrate a clear relationship between temperature and first-year sea ice extent in the Arctic and suggest multi-year sea ice will continue to decline as polar amplification drives Arctic temperatures beyond the 2 °C global average warming target of the recent COP21 Paris climate agreement.

  9. Bromine-82 Labelling of Human Serum Albumin, Insulin and Fibrinogen by Electrochemical Means

    International Nuclear Information System (INIS)

    The authors describe results obtained with a method using bromine-82 to label human serum albumin, fibrinogen and insulin, three organic substances of special importance in diagnostics and biological research. The method involves electrolytic bromination in an aqueous solution; this is performed in an electrolysis cell, whose anodic zone containing the substance to be labelled is partitioned from the cathodic zone by a dialysis membrane. For each of the three substances mentioned, the degree of bromination produced by a direct current (200, 200, 300 x 10-6 Å) was studied as a function of anode potential in 10-3 and 10-4 M solutions of NH4Br, the amount of bromine-labelled substance formed being checked by radio electrophoresis for various anodic potential values differing from each other by 50 mV. By immuno- electrophoresis it was ascertained that denaturation of albumin and fibrinogen only starts at anodic potential values for which the degree of labelling is already very high as compared with that yielded by chemical methods of labelling. The method here described has the advantage of rapid execution and is well suited to remote handling in a shielded zone. (author)

  10. In vitro profiling of the endocrine-disrupting potency of brominated flame retardants

    NARCIS (Netherlands)

    Hamers, T.H.M.; Kamstra, J.H.; Sonneveld, E.; Murk, A.J.; Kester, M.H.A.; Andersson, P.L.; Legler, J.; Brouwer, A.

    2006-01-01

    Over the last years, increasing evidence has become available that some brominated flame retardants (BFRs) may have endocrine disrupting (ED) potencies. The goal of the current study was to perform a systematic in vitro screening of the ED potencies of BFRs (1) to elucidate possible modes of action

  11. Molecular characterization of brominated persistent pollutants using extended X-ray absorption fine structure (EXAFS) spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Bergknut, Magnus; Skyllberg, Ulf [Swedish University of Agricultural Sciences (SLU), Department of Forest Ecology and Management, Umeaa (Sweden); Persson, Per [Umeaa University, Department of Chemistry, Umeaa (Sweden)

    2008-02-15

    X-ray absorption fine structure (EXAFS) spectroscopy spectra were collected for three brominated persistent pollutants: 6-bromo-2,4,5-trichlorophenol (BrTriClP), pentabromophenol (PentaBrP) and 3,3',5,5'-tetrabromobisphenol A (TBBA). The substances were selected to be symmetrical (BrTriClP and TBBA) or asymmetrical (PentaBrP) with respect to the atomic Br positions and to differ in the number of bromine and other halide atoms, as well as their relative positions. The asymmetrical PentaBrP was modelled with special detail as not all bromine atoms have identical coordination environments. The studied substances displayed unique EXAFS spectra, which could be used to determine the molecular structure in fair detail. We conclude that EXAFS spectroscopy is a suitable technique for molecular characterization of the comparatively complex molecules within the class of compounds of brominated organic persistent pollutants. A detailed understanding of the EXAFS spectra of the pure compounds opens up possibilities to study the interactions with soil and sediment matrices by means of EXAFS spectroscopy. (orig.)

  12. Deposition history of brominated flame retardant compounds in an ice core from Holtedahlfonna, Svalbard, Norway

    NARCIS (Netherlands)

    Hermanson, M.H.; Isaksson, E.; Forsström, S.; Teixeira, C.; Muir, D.C.G.; Pohjola, V.A.; van de Wal, R.S.W.

    2010-01-01

    Brominated flame retardants (BFRs) have been found in Arctic wildlife, lake sediment, and air. To identify the atmospheric BFR deposition history on Svalbard, Norway, we analyzed 19 BFRs, including hexabromocyclododecane (HBCD), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), decabromodiphenyl ethane

  13. Kinetics of aerobic cometabolic biodegradation of chlorinated and brominated aliphatic hydrocarbons: A review.

    Science.gov (United States)

    Jesus, João; Frascari, Dario; Pozdniakova, Tatiana; Danko, Anthony S

    2016-05-15

    This review analyses kinetic studies of aerobic cometabolism (AC) of halogenated aliphatic hydrocarbons (HAHs) from 2001-2015 in order to (i) compare the different kinetic models proposed, (ii) analyse the estimated model parameters with a focus on novel HAHs and the identification of general trends, and (iii) identify further research needs. The results of this analysis show that aerobic cometabolism can degrade a wide range of HAHs, including HAHs that were not previously tested such as chlorinated propanes, highly chlorinated ethanes and brominated methanes and ethanes. The degree of chlorine mineralization was very high for the chlorinated HAHs. Bromine mineralization was not determined for studies with brominated aliphatics. The examined research period led to the identification of novel growth substrates of potentially high interest. Decreasing performance of aerobic cometabolism were found with increasing chlorination, indicating the high potential of aerobic cometabolism in the presence of medium- and low-halogenated HAHs. Further research is needed for the AC of brominated aliphatic hydrocarbons, the potential for biofilm aerobic cometabolism processes, HAH-HAH mutual inhibition and the identification of the enzymes responsible for each aerobic cometabolism process. Lastly, some indications for a possible standardization of future kinetic studies of HAH aerobic cometabolism are provided. PMID:26874310

  14. Toxicity of brominated flame retardants in fish, with emphasis on endocrine effects and reproduction

    NARCIS (Netherlands)

    Kuiper, R.V.

    2007-01-01

    Abstract The abundant use of brominated flame retardants (BFRs) in modern polymers has over the passed decades resulted in contamination of the environment, and BFRs are increasingly found in fish. Laboratory studies have shown that a number of BFRs and BFR-metabolites can interfere with thyroid and

  15. Brominated Flame Retardants in the Environment - The Price for our Convenience?

    NARCIS (Netherlands)

    Boer, de J.

    2004-01-01

    This paper reviews information on the occurrence of brominated flame retardants (BFRs) in various environmental compartments. The lack of information on BFRs other than pentabrominated diphenylethers (pentaBDEs) is emphasized, as well as the need for better analytical methods and the need for more t

  16. Brominated Flame Retardants and their metabolites: Novel insights into endocrine disruptive properties.

    NARCIS (Netherlands)

    Fernández Cantón, R.

    2008-01-01

    Brominated flame retardants (BFRs) are chemicals that are added to materials to inhibit or suppress ignition and are incorporated during the manufacture of e.g. electronic equipment, furniture, construction materials and textiles. BFRs have become an increasingly important group of organohalogen com

  17. Canadian Arctic sea ice reconstructed from bromine in the Greenland NEEM ice core

    Science.gov (United States)

    Spolaor, Andrea; Vallelonga, Paul; Turetta, Clara; Maffezzoli, Niccolò; Cozzi, Giulio; Gabrieli, Jacopo; Barbante, Carlo; Goto-Azuma, Kumiko; Saiz-Lopez, Alfonso; Cuevas, Carlos A.; Dahl-Jensen, Dorthe

    2016-01-01

    Reconstructing the past variability of Arctic sea ice provides an essential context for recent multi-year sea ice decline, although few quantitative reconstructions cover the Holocene period prior to the earliest historical records 1,200 years ago. Photochemical recycling of bromine is observed over first-year, or seasonal, sea ice in so-called “bromine explosions” and we employ a 1-D chemistry transport model to quantify processes of bromine enrichment over first-year sea ice and depositional transport over multi-year sea ice and land ice. We report bromine enrichment in the Northwest Greenland Eemian NEEM ice core since the end of the Eemian interglacial 120,000 years ago, finding the maximum extension of first-year sea ice occurred approximately 9,000 years ago during the Holocene climate optimum, when Greenland temperatures were 2 to 3 °C above present values. First-year sea ice extent was lowest during the glacial stadials suggesting complete coverage of the Arctic Ocean by multi-year sea ice. These findings demonstrate a clear relationship between temperature and first-year sea ice extent in the Arctic and suggest multi-year sea ice will continue to decline as polar amplification drives Arctic temperatures beyond the 2 °C global average warming target of the recent COP21 Paris climate agreement. PMID:27650478

  18. Thermoelectric properties of bromine filled CoSb3 skutterudite

    Energy Technology Data Exchange (ETDEWEB)

    Ortiz, Brenden R.; Crawford, Caitlin M.; McKinney, Robert W.; Parilla, Philip A.; Toberer, Eric S.

    2016-01-01

    Historically, the improved thermoelectric performance of skutterudite compounds has largely been driven by the incorporation of electropositive donors on interstitial sites. These 'rattlers' serve to optimize both electronic and thermal properties by tuning the carrier concentration and scattering phonons. In this work, we show that interstitial bromine can be incorporated into CoSb3 and assess the impact on electronic and thermal transport. In contrast to prior high pressure syntheses with iodine, interstitial bromine incorporation is achieved at ambient pressure. Transport properties are stable up to at least 375 degrees C. Bromine serves as an electronegative acceptor and can induce degenerate (>5 x 1019 cm-3) hole densities. In contrast to other p-type skutterudite compositions, bromine preserves the intrinsically high hole mobility of CoSb3 while significantly reducing the lattice thermal conductivity. The development of a stable p-type dopant for the interstitial filler site enables the development of skutterudites with both donor and acceptor interstitials to maximize phonon scattering while maintaining the high mobility of CoSb3.

  19. Trapping radiodine, in the form of methyl iodide, on nuclear carbon

    Energy Technology Data Exchange (ETDEWEB)

    Nacapricha, D. [Mahidol Univ., Bangkok (Thailand); Taylor, C. [John Moores Univ., Liverpool (United Kingdom)

    1996-12-31

    Studies have been performed on potassium-iodide-impregnated charcoals of the type used in the nuclear industry for trapping radioiodine released during nuclear fission. The effects of various parameters on the trapping efficiency of methyl iodide have been investigated. A variation in particle size within a bulk charcoal caused poor precision in K value measurements because of differences in surface area, pore volume, and bed density, leading to differences in the deposition of the impregnant. Precision is improved by sieving the charcoal to a narrower size because smaller particles have a higher porosity. This finding is supported by surface area and pore measurements. Two methods of impregnation are compared by measuring K values and the deposition of potassium iodide. Charcoal impregnated by rotary evaporation exhibits both higher K values and higher potassium iodide contents than sprayed charcoal. Two designs of spraying drum are compared: a drum with helical vanes allows more efficient deposition and more uniform distribution of impregnant than a drum with axial vanes. A decrease in the K value with increasing humidity correlates with the available surface area. A similar correlation exists between water content and available pore volume. Aging of potassium-iodide-impregnated charcoal, caused by the formation of oxygen complexes on the surface, is associated with significant falls in K value. K values of charcoals also can be restored to at least their original values by heat treatment in the absence of air. 12 refs., 6 figs., 1 tab.

  20. Processes of adsorption/desorption of iodides and cadmium cations onto/from Ag(111

    Directory of Open Access Journals (Sweden)

    VLADIMIR D. JOVIĆ

    2011-02-01

    Full Text Available In this work, the adsorption/desorption processes of iodides and cadmium cations in the presence of iodides onto/from Ag(111 were investigated. It was shown that both processes were complex, characterized by several peaks on the cyclic voltammograms (CVs. By PeakFit analysis of the recorded CVs and subsequent fitting of the obtained peaks by the Frumkin adsorption isotherm, the interaction parameter (f and the Gibbs energy of adsorption (DGads for each adsorbed phase were determined. In the case of iodide adsorption, four peaks were characterized by negative values of f, indicating attractive lateral interaction between the adsorbed anions, while two of them possessed value of f < –4, indicating phase transition processes. The adsorption/desorption processes of cadmium cations (underpotential deposition – UPD of cadmium in the presence of iodide anions was characterized by two main peaks, each of them being composed of two or three peaks with negative values of f. By the analysis of charge vs. potential dependences obtained either from the CVs or current transients on potentiostatic pulses, it was concluded that adsorbed iodides did not undergo desorption during the process of Cd UPD, but became replaced by Cd ad-atoms and remained adsorbed on top of a Cd layer and/or in between Cd the ad-atoms.

  1. [Determination of iodide, thiocyanate and perchlorate ions in environmental water by two-dimensional ion chromatography].

    Science.gov (United States)

    Lin, Li; Wang, Haibo; Shi, Yali

    2013-03-01

    A procedure for the determination of iodide, thiocyanate and perchlorate ions in environmental water by two-dimensional ion chromatography has been developed. At first the iodide, thiocyanate and perchlorate ions were separated from interfering ions by a column (IonPac AS16, 250 mm x 4 mm). The iodide ion, thiocyanate and perchlorate ions were then enriched with an enrichment column (MAC-200, 80 mm x 0.75 mm). In the 2nd-dimensional chromatography, iodide thiocyanate and perchlorate ions were separated and quantified by a capillary column (IonPac AS20 Capillary, 250 mm x 0.4 mm). The linear ranges were 0.05 -100 pg/L with correlation coefficients of 0. 999 9, and the detection limits were 0. 02 - 0.05 micro gg/L. The spiked recoveries of iodide, thiocyanate and perchlorate ions were in the range of 85.1% to 100.1%. The relative standard deviations of the recoveries were 1.7% to 4.9%.

  2. Proton and iodine-127 nuclear magnetic resonance studies on the binding of iodide by lactoperoxidase

    Energy Technology Data Exchange (ETDEWEB)

    Sakurada, J.; Takahashi, S.; Shimizu, T.; Hatano, M.; Nakamura, S.; Hosoya, T.

    1987-10-06

    Interaction of an iodide ion with lactoperoxidase was studied by the use of /sup 1/H NMR, /sup 127/I NMR, and optical difference spectrum techniques. /sup 1/H NMR spectra demonstrated that a major broad hyperfine-shifted signal at about 60 ppm, which is ascribed to the heme peripheral methyl protons, was shifted toward high field by adding KI, indicating the binding of iodide to the active site of the enzyme; the dissociation constant was estimated to be 38 mM at pH 6.1. The binding was further detected by /sup 127/I NMR, showing no competition with cyanide. Both /sup 1/H NMR and /sup 127/I NMR revealed that the binding of iodide to the enzyme is facilitated by the protonation of an ionizable group with a pK/sup a/ value of 6.0-6.8, which is presumably the distal histidyl residue. Optical difference spectra showed that the binding of an aromatic donor molecule to the enzyme is slightly but distinctly affected by adding KI. On the basis of these results, it was suggested that an iodide ion binds to lactoperoxidase outside the heme crevice but at the position close enough to interact with the distal histidyl residue which possibly mediates electron transport in the iodide oxidation reaction.

  3. Alpha-lipoic acid induces sodium iodide symporter expression in TPC-1 thyroid cancer cell line

    International Nuclear Information System (INIS)

    Introduction: Patients with metastatic thyroid cancers that do not uptake iodine need effective therapeutic option. Differentiation-inducing agents have been tried to restore functional expression of sodium iodide symporter (NIS) without success. Our objective was to assess the effect of alpha-lipoic acid (ALA), known as potential antioxidant, on expression of sodium iodide symporter in thyroid cancer cells. Methods: Human thyroid cancer-derived cell lines, TPC-1, were treated with ALA, and changes in NIS mRNA and protein expression were measured. ALA's effect on NIS gene promoter was evaluated, and functional NIS expression was assessed by iodide uptake assay. Results: Treatment with ALA increased NIS mRNA expression up to ten folds of control dose-dependently after 24 h of exposure. ALA increased NIS promoter activity, and increased iodide uptake by 1.6 fold. ALA induced expression of NIS protein, but had no significant effect on the plasma membrane trafficking. ALA increased phosphorylation of CREB and nuclear translocation of pCREB, and co-treatment of ALA and trichostatin A increased iodide uptake by three folds in TPC-1 cells. Conclusions: ALA is a potential agent to increase NIS transcription in TPC-1. It could be used as an adjunctive agent to increase efficacy of radioiodine therapy if combined with a strategy to increase NIS protein trafficking to cell membrane.

  4. The Effects of Bromination Methods on the Microstructure of Brominated Natural Rubbers from Latex%溴化方式对胶乳法溴化天然橡胶结构的影响

    Institute of Scientific and Technical Information of China (English)

    赵法敏; 薛行华; 张子琦; 张利伟; 李光

    2013-01-01

    为改善溴化天然橡胶(BNR)的溶解性能,在胶乳法的基础上改变溴化方式,以常规溴化方式和分步溴化方式分别制备了BNR.通过实验发现,体系溴浓度相同时分步溴化方式的溴含量比常规溴化方式高,而凝胶含量较低,所以分步溴化方式在甲苯中的溶解性能较好.通过傅里叶红外光谱对样品进行表征,并使用核磁共振对其微观结构进行了定性定量分析.红外光谱分析表明,2种溴化方式制备的BNR产物均发生了一定程度的溴加成反应和溴取代反应;核磁共振的分析证实了在体系溴浓度较低的情况下,与胶乳法常规溴化相反,胶乳法分步溴化的溴化过程主要以溴加成反应为主,少量发生溴取代反应.%In order to improve the solubility property of the brominated natural rubbers (BNR)from latex, BNR were prepared by changing the bromination ways from conventional bromination to step bromination. Through the experiment, it was discovered that the bromine content of the latter was higher than the former, but the gel content was less under the same bromine concentration. The latter showed much better solubility in the solvent of toluene. The structure of the procured sample was characterized by Fourier transform infrared spectroscopy (FTIR), and the microstructures of brominated nature rubber were qualitatively and quantitatively analyzed by nuclear magnetic resonance (NMR). FTIR showed that there were both a degree of brominated addition reaction and brominated substitution reaction in the obtained BNR by two different methods; Contrary to the conventional bromination from latex, the analysis of NMR proved that the bromination process of step bromination from latex was mainly in the form of addition reaction, and only a small amount of the substitution reaction did occur.

  5. Bromine release from blowing snow and its impact on tropospheric chemistry

    Science.gov (United States)

    Griffiths, Paul; Yang, Xin; Abraham, N. Luke; Archibald, Alexander; Pyle, John

    2016-04-01

    In the last two decades, significant depletion of boundary layer ozone (ozone depletion events, ODEs) has been observed in both Arctic and Antarctic spring. ODEs are attributed to catalytic destruction by bromine radicals (Br plus BrO), especially during bromine explosion events (BEs), when high concentrations of BrO periodically occur. The source of bromine and the mechanism that sustains the high BrO levels are still the subject of study. Recent work by Pratt et al. (2013) posits Br2 production within saline snow and sea ice which leads to sudden ODEs. Previously, Yang et al. (2008) suggested snow could provide a source of (depleted) sea-salt aerosol if wicked from the surface of ice. They suggest that rapid depletion of bromide from the aerosol will constitute a source of photochemical Bry. Given the large sea ice extent in polar regions, this may constitute a significant source of sea salt and bromine in the polar lower atmosphere. While bromine release from blowing snow is perhaps less likely to trigger sudden ODEs, it may make a contribution to regional scale processes affecting ozone levels. Currently, the model parameterisations of Yang et al. assumes that rapid release of bromine occurs from fresh snow on sea ice during periods of strong wind. The parameterisation depends on an assumed sea-salt aerosol distribution generated via sublimation of the snow above the boundary layer, as well as taking into account the salinity of the snow. In this work, we draw on recent measurements by scientists from the British Antarctic Survey during a cruise aboard the Polarstern in the southern oceans. This has provided an extensive set of measurements of the chemical and physical characteristics of blowing snow over sea ice, and of the aerosol associated with it. Based on the observations, we have developed an improved parameterisation of the release of bromine from blowing snow. The paper presents results from the simulation performed using the United Kingdom Chemistry

  6. X-ray imaging performance of structured cesium iodide scintillators.

    Science.gov (United States)

    Zhao, Wei; Ristic, Goran; Rowlands, J A

    2004-09-01

    Columnar structured cesium iodide (CsI) scintillators doped with Thallium (Tl) have been used extensively for indirect x-ray imaging detectors. The purpose of this paper is to develop a methodology for systematic investigation of the inherent imaging performance of CsI as a function of thickness and design type. The results will facilitate the optimization of CsI layer design for different x-ray imaging applications, and allow validation of physical models developed for the light channeling process in columnar CsI layers. CsI samples of different types and thicknesses were obtained from the same manufacturer. They were optimized either for light output (HL) or image resolution (HR), and the thickness ranged between 150 and 600 microns. During experimental measurements, the CsI samples were placed in direct contact with a high resolution CMOS optical sensor with a pixel pitch of 48 microns. The modulation transfer function (MTF), noise power spectrum (NPS), and detective quantum efficiency (DQE) of the detector with different CsI configurations were measured experimentally. The aperture function of the CMOS sensor was determined separately in order to estimate the MTF of CsI alone. We also measured the pulse height distribution of the light output from both the HL and HR CsI at different x-ray energies, from which the x-ray quantum efficiency, Swank factor and x-ray conversion gain were determined. Our results showed that the MTF at 5 cycles/mm for the HR type was 50% higher than for the HL. However, the HR layer produces approximately 36% less light output. The Swank factor below K-edge was 0.91 and 0.93 for the HR and HL types, respectively, thus their DQE(0) were essentially identical. The presampling MTF decreased as a function of thickness L. The universal MTF, i.e., MTF plotted as a function of the product of spatial frequency f and CsI thickness L, increased as a function of L. This indicates that the light channeling process in CsI improved the MTF of

  7. Monitoring of WEEE plastics in regards to brominated flame retardants using handheld XRF

    Energy Technology Data Exchange (ETDEWEB)

    Aldrian, Alexia, E-mail: alexia.aldrian@unileoben.ac.at [Chair of Waste Processing Technology and Waste Management, Montanuniversitaet Leoben, Franz-Josef-Straße 18, 8700 Leoben (Austria); Ledersteger, Alfred, E-mail: a.ledersteger@saubermacher.at [Saubermacher Dienstleistungs AG, Hans-Roth-Straße 1, 8073 Feldkirchen bei Graz (Austria); Pomberger, Roland, E-mail: roland.pomberger@unileoben.ac.at [Chair of Waste Processing Technology and Waste Management, Montanuniversitaet Leoben, Franz-Josef-Straße 18, 8700 Leoben (Austria)

    2015-02-15

    Highlights: • Specification of an empirical factor for conversion from bromine to PBB and PBDE. • The handheld XRF device was validated for this particular application. • A very large number of over 4600 pieces of monitor housings was analysed. • The recyclable fraction mounts up to 85% for TV but only 53% of PC waste plastics. • A high percentage of pieces with bromine contents of over 50,000 ppm was obtained. - Abstract: This contribution is focused on the on-site determination of the bromine content in waste electrical and electronic equipment (WEEE), in particular waste plastics from television sets (TV) and personal computer monitors (PC) using a handheld X-ray fluorescence (XRF) device. The described approach allows the examination of samples in regards to the compliance with legal specifications for polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDEs) directly after disassembling and facilitates the sorting out of plastics with high contents of brominated flame retardants (BFRs). In all, over 3000 pieces of black (TV) and 1600 pieces of grey (PC) plastic waste were analysed with handheld XRF technique for this study. Especially noticeable was the high percentage of pieces with a bromine content of over 50,000 ppm for TV (7%) and PC (39%) waste plastics. The applied method was validated by comparing the data of handheld XRF with results obtained by GC–MS. The results showed the expected and sufficiently accurate correlation between these two methods. It is shown that handheld XRF technique is an effective tool for fast monitoring of large volumes of WEEE plastics in regards to BFRs for on-site measurements.

  8. Distribution of copper, silver and gold during thermal treatment with brominated flame retardants

    Energy Technology Data Exchange (ETDEWEB)

    Oleszek, Sylwia, E-mail: sylwia_oleszek@yahoo.com [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 1,1 Katahira, 2-Chome, Sendai 980-8577 (Japan); Institute of Environmental Engineering of the Polish Academy of Sciences, 34 M. Sklodowska-Curie St., 41-819 Zabrze (Poland); Grabda, Mariusz, E-mail: mariusz@mail.tagen.tohoku.ac.jp [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 1,1 Katahira, 2-Chome, Sendai 980-8577 (Japan); Institute of Environmental Engineering of the Polish Academy of Sciences, 34 M. Sklodowska-Curie St., 41-819 Zabrze (Poland); Shibata, Etsuro, E-mail: etsuro@tagen.tohoku.ac.jp [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 1,1 Katahira, 2-Chome, Sendai 980-8577 (Japan); Nakamura, Takashi, E-mail: ntakashi@tagen.tohoku.ac.jp [Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, 1,1 Katahira, 2-Chome, Sendai 980-8577 (Japan)

    2013-09-15

    Highlights: • Copper, silver and gold during thermal treatment with brominated flame retardants. • Distribution of copper, silver and gold during thermal processing. • Thermodynamic considerations of the bromination reactions. - Abstract: The growing consumption of electric and electronic equipment results in creating an increasing amount of electronic waste. The most economically and environmentally advantageous methods for the treatment and recycling of waste electric and electronic equipment (WEEE) are the thermal techniques such as direct combustion, co-combustion with plastic wastes, pyrolysis and gasification. Nowadays, this kind of waste is mainly thermally treated in incinerators (e.g. rotary kilns) to decompose the plastics present, and to concentrate metals in bottom ash. The concentrated metals (e.g. copper, precious metals) can be supplied as a secondary raw material to metal smelters, while the pyrolysis of plastics allows the recovery of fuel gases, volatilising agents and, eventually, energy. Indeed, WEEE, such as a printed circuit boards (PCBs) usually contains brominated flame retardants (BFRs). From these materials, hydrobromic acid (HBr) is formed as a product of their thermal decomposition. In the present work, the bromination was studied of copper, silver and gold by HBr, originating from BFRs, such as Tetrabromobisphenol A (TBBPA) and Tetrabromobisphenol A-Tetrabromobisophenol A diglycidyl ether (TTDE) polymer; possible volatilization of the bromides formed was monitored using a thermo-gravimetric analyzer (TGA) and a laboratory-scale furnace for treating samples of metals and BFRs under an inert atmosphere and at a wide range of temperatures. The results obtained indicate that up to about 50% of copper and silver can evolve from sample residues in the form of volatile CuBr and AgBr above 600 and 1000 °C, respectively. The reactions occur in the molten resin phase simultaneously with the decomposition of the brominated resin. Gold is

  9. A case study of a transported bromine explosion event in the Canadian high arctic

    Science.gov (United States)

    Zhao, X.; Strong, K.; Adams, C.; Schofield, R.; Yang, X.; Richter, A.; Friess, U.; Blechschmidt, A.-M.; Koo, J.-H.

    2016-01-01

    Ozone depletion events in the polar troposphere have been linked to extremely high concentrations of bromine, known as bromine explosion events (BEE). However, the optimum meteorological conditions for the occurrence of these events remain uncertain. On 4-5 April 2011, a combination of both blowing snow and a stable shallow boundary layer was observed during a BEE at Eureka, Canada (86.4°W, 80.1°N). Measurements made by a Multi-Axis Differential Optical Absorption Spectroscopy spectrometer were used to retrieve BrO profiles and partial columns. During this event, the near-surface BrO volume mixing ratio increased to ~20 parts per trillion by volume, while ozone was depleted to ~1 ppbv from the surface to 700 m. Back trajectories and Global Ozone Monitoring Experiment-2 satellite tropospheric BrO columns confirmed that this event originated from a bromine explosion over the Beaufort Sea. From 30 to 31 March, meteorological data showed high wind speeds (24 m/s) and elevated boundary layer heights (~800 m) over the Beaufort Sea. Long-distance transportation (~1800 km over 5 days) to Eureka indicated strong recycling of BrO within the bromine plume. This event was generally captured by a global chemistry-climate model when a sea-salt bromine source from blowing snow was included. A model sensitivity study indicated that the surface BrO at Eureka was controlled by both local photochemistry and boundary layer dynamics. Comparison of the model results with both ground-based and satellite measurements confirmed that the BEE observed at Eureka was triggered by transport of enhanced BrO from the Beaufort Sea followed by local production/recycling under stable atmospheric shallow boundary layer conditions.

  10. Amines and ammonium compounds. CXCVIII. Reaction of ammonium salts containing a 2-alkynyl group with bromine and iodine

    Energy Technology Data Exchange (ETDEWEB)

    Gyul' nazaryan, A.K.; Khachatryan, N.G.; Saakyan, T.A.; Kinoyan, F.S.; Panosyan, G.A.; Babayan, A.T.

    1988-08-10

    The reactions of monoammonium, 1,4-and 1,5-bistertiaryammonium, and bisquaternary ammonium salts containing a 2-alkynyl group with bromine and iodine were studied. It was shown that these salts form molecular complexes with iodine and that addition of iodine at the triple bond does not occur. In reaction with bromine in all cases except 1,4-bistrimethylammonio-2-butyne dihalides one molecule of the halogen adds at the triple bond with the formation of salts containing the 2,3-dibromo-2-alkenyl group, which then form a 1:1 complex with bromine.

  11. The effect of bromination of carbon fibers on the coefficient of thermal expansion of graphite fiber-epoxy composites

    Science.gov (United States)

    Jaworske, D. A.; Maciag, C.

    1987-01-01

    To examine the effect of bromination of carbon fibers on the coefficient of thermal expansion (CTE) of carbon fiber epoxy composites, several pristine and brominated carbon fiber-epoxy composite samples were subjected to thermomechanical analysis. The CTE's of these samples were measured in the uniaxial and transverse directions. The CTE was dominated by the fibers in the uniaxial direction, while it was dominated by the matrix in the transverse directions. Bromination had no effect on the CTE of any of the composites. In addition, the CTE of fiber tow was measured in the absence of a polymer matrix, using an extension probe. The results from this technique were inconclusive.

  12. Doping in mercuric iodide crystals and its influence on electronic properties and material structure

    International Nuclear Information System (INIS)

    Doping of mercuric iodide single crystals with SbI3 was studied. Three major aspects of the influence of doping were investigated: the α to β solid phase transition, the crystal structure and the semiconducting properties. A controlled doping method and a new growth technique from the melt were developed. A quantitative correlation between the antimony concentration and the charge carrier transport properties as well as the nuclear detector characteristics of HgI2 were established for the first time. In the present work the influence of various impurities (Sb, Cu, Ag, Bi) on the solid state phase transformation of mercuric iodide has been investigated. In the second part of the work a new growth method for mercuric iodide single crystals containing a controlled amount of SbI3, has been developed. In the last part of this work the influence of the presence of impurities in the crystal on the charge carrier transport properties has been investigated. (author)

  13. Quantification of propidium iodide delivery with millisecond electric pulses: A model study

    CERN Document Server

    Yu, Miao

    2014-01-01

    A model study of propidium iodide delivery with millisecond electric pulses is presented; this work is a companion of the experimental efforts by Sadik et al. [1]. Both membrane permeabilization and delivery are examined with respect to six extra-cellular conductivities. The transmembrane potential of the permeabilized regions exhibits a consistent value, which corresponds to a bifurcation point in the pore-radius-potential relation. Both the pore area density and membrane conductance increase with an increasing extra-cellular conductivity. On the other hand, the inverse correlation between propidium iodide delivery and extra-cellular conductivity as observed in the experiments is quantitatively captured by the model. This agreement confirms that this behavior is primarily mediated by electrophoretic transport during the pulse. The results suggest that electrophoresis is important even for the delivery of small molecules such as propidium iodide. The direct comparison between model prediction and experimental...

  14. Iodide retention by cinnabar (HgS) and chalcocite (Cu{sub 2}S)

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, H.L.; Balsley, S.D.; Brady, P.V.

    1995-07-01

    Sorption of iodide (I{sup {minus}}) on cinnabar (HgS) and chalcocite (Cu{sub 2}S) was examined as a function of pH at 25{degrees}C in a series of batch experiments. Calculated distribution ratios (K{sub d}) far exceed those reported for other minerals; maximal K{sub d}`s of 1375 cc/g (Cu{sub 2}S) and 3080 c/g (HgS) were observed between pH 4-5, but wre substantial at all pH`s measured (4 < pH < 10). Iodide sorption apparently occurs by the formation of an insoluble surface solid solution with exposed Hg and Cu sites. Surface solid solution formation is favored at low pH due to the lessened electrostatic repulsion of the iodide ion by the sulfide surfaces.

  15. Global atmospheric model for mercury including oxidation by bromine atoms

    Directory of Open Access Journals (Sweden)

    C. D. Holmes

    2010-12-01

    Full Text Available Global models of atmospheric mercury generally assume that gas-phase OH and ozone are the main oxidants converting Hg0 to HgII and thus driving mercury deposition to ecosystems. However, thermodynamic considerations argue against the importance of these reactions. We demonstrate here the viability of atomic bromine (Br as an alternative Hg0 oxidant. We conduct a global 3-D simulation with the GEOS-Chem model assuming gas-phase Br to be the sole Hg0 oxidant (Hg + Br model and compare to the previous version of the model with OH and ozone as the sole oxidants (Hg + OH/O3 model. We specify global 3-D Br concentration fields based on our best understanding of tropospheric and stratospheric Br chemistry. In both the Hg + Br and Hg + OH/O3 models, we add an aqueous photochemical reduction of HgII in cloud to impose a tropospheric lifetime for mercury of 6.5 months against deposition, as needed to reconcile observed total gaseous mercury (TGM concentrations with current estimates of anthropogenic emissions. This added reduction would not be necessary in the Hg + Br model if we adjusted the Br oxidation kinetics downward within their range of uncertainty. We find that the Hg + Br and Hg + OH/O3 models are equally capable of reproducing the spatial distribution of TGM and its seasonal cycle at northern mid-latitudes. The Hg + Br model shows a steeper decline of TGM concentrations from the tropics to southern mid-latitudes. Only the Hg + Br model can reproduce the springtime depletion and summer rebound of TGM observed at polar sites; the snowpack component of GEOS-Chem suggests that 40% of HgII deposited to snow in the Arctic is transferred to the ocean and land reservoirs, amounting to a net deposition flux to the Arctic of 60 Mg a−1. Summertime events of depleted Hg0 at Antarctic sites due to subsidence are much better simulated by

  16. Global atmospheric model for mercury including oxidation by bromine atoms

    Directory of Open Access Journals (Sweden)

    C. D. Holmes

    2010-08-01

    Full Text Available Global models of atmospheric mercury generally assume that OH and ozone are the main oxidants converting Hg0 to HgII and thus driving mercury deposition to ecosystems. However, thermodynamic considerations argue against the importance of these reactions. We demonstrate here the viability of atomic bromine (Br as an alternative Hg0 oxidant. We conduct a global 3-D simulation with the GEOS-Chem model assuming Br to be the sole Hg0 oxidant (Hg + Br model and compare to the previous version of the model with OH and ozone as the sole oxidants (Hg + OH/O3 model. We specify global 3-D Br concentration fields based on our best understanding of tropospheric and stratospheric Br chemistry. In both the Hg + Br and Hg + OH/O3 models, we add an aqueous photochemical reduction of HgII in cloud to impose a tropospheric lifetime for mercury of 6.5 months against deposition, as needed to reconcile observed total gaseous mercury (TGM concentrations with current estimates of anthropogenic emissions. This added reduction would not be necessary in the Hg + Br model if we adjusted the Br oxidation kinetics downward within their range of uncertainty. We find that the Hg + Br and Hg + OH/O3 models are equally capable of reproducing the spatial distribution of TGM and its seasonal cycle at northern mid-latitudes. The Hg + Br model shows a steeper decline of TGM concentrations from the tropics to southern mid-latitudes. Only the Hg + Br model can reproduce the springtime depletion and summer rebound of TGM observed at polar sites; the snowpack component of GEOS-Chem suggests that 40% of HgII deposited to snow in the Arctic is transferred to the ocean and land reservoirs, amounting to a net deposition flux of 60 Mg a−1. Summertime events of depleted Hg0 at Antarctic sites due to subsidence are much better simulated by the Hg + Br model. Model

  17. All-Solid-State Iodide Selective Electrode for Iodimetry of Iodized Salts and Vitamin C

    Directory of Open Access Journals (Sweden)

    TIRUWORK MEQUANINT

    2012-12-01

    Full Text Available A laboratory-made all-solid state iodide selective electrode, with Ag2S-AgI coated on a graphite rod recovered from dry cell battery, was prepared according to previous procedures. The electrode’s linear response to iodide was in the concentration range of 10-6 M to 10-1 M with a slope of 56.85 mV/decade and a detection limit of 6×10-7M. Iodate recovery test for laboratory formulated iodate-iodized salt was found to be 98.6 % with a standard deviation of 1.14%. The titratability of the iodized salt solution was at least 10-200 ppm potassium iodate (6-120 ppm iodine, exhibiting distinct endpoints in the range wider than the ones set in regulatory standards and reflecting that QC monitoring in production and stability decline of iodine content upon storage can be performed with the electrode method. On the basis this potentiometric titration, the application of the laboratory-made iodide electrode (vs. a saturated calomel reference electrode was extended to the determination of iodine in commercial iodized salts. In all the iodine assays, the iodate-iodized salt was initially treated with acid and an excess of iodide before titration against Na2S2O3 solution. The iodine content in table salts iodized with iodide was determined by direct potentiometry. The electrode was further used for vitamin C (ascorbic acid determinations in pharmaceutical tablets and orange juice by back titrating excess I3- against standard Na2S2O3 in acidic media. The overall outcome is that the iodide ISE can be used as sharp endpoint indicator for these titrimetric reactions in place of the well known official, but visually monitored, starch- triodide end-point reaction detection.

  18. Modeling of Turing Structures in the Chlorite-Iodide-Malonic Acid-Starch Reaction System

    Science.gov (United States)

    Lengyel, Istivan; Epstein, Irving R.

    1991-02-01

    Recent experiments on the chlorite-iodide-malonic acid-starch reaction in a gel reactor give the first evidence of the existence of the symmetry breaking, reaction-diffusion structures predicted by Turing in 1952. A five-variable model that describes the temporal behavior of the system is reduced to a two-variable model, and its spatial behavior is analyzed. Structures have been found with wavelengths that are in good agreement with those observed experimentally. The gel plays a key role by binding key iodine species, thereby creating the necessary difference in the effective diffusion coefficients of the activator and inhibitor species, iodide and chlorite ions, respectively.

  19. Iodide uptake in human anaplastic thyroid carcinoma cells after transfer of the human thyroid peroxidase gene

    Energy Technology Data Exchange (ETDEWEB)

    Haberkom, U. [Clinical Cooperation Unit Nuclear Medicine, German Cancer Research Center, Heidelberg (Germany); Dept. of Nuclear Medicine, Univ. of Heidelberg (Germany); Altmann, A.; Jiang, S.; Morr, I.; Mahmut, M. [Clinical Cooperation Unit Nuclear Medicine, German Cancer Research Center, Heidelberg (Germany); Eisenhut, M. [Dept. of Nuclear Medicine, Univ. of Heidelberg (Germany)

    2001-05-01

    Human thyroperoxidase (hTPO) is critical for the accumulation of iodide in thyroid tissues. Poorly differentiated and anaplastic thyroid tumours which lack thyroid-specific gene expression fail to accumulate iodide and, therefore, do not respond to iodine-131 therapy. We consequently investigated whether transfer of the hTPO gene is sufficient to restore the iodide-trapping capacity in undifferentiated thyroid and non-thyroid tumour cells. The human anaplastic thyroid carcinoma cell lines C643 and SW1736, the rat Morris hepatoma cell line MH3924A and the rat papillary thyroid carcinoma cell line L2 were used as in vitro model systems. Employing a bicistronic retroviral vector based on the myeloproliferative sarcoma virus for the transfer of the hTPO and the neomycin resistance gene, the C643 cells and SW1736 cells were transfected while the L2 cells and MH3924A cells were infected with retroviral particles. Seven recombinant C643 and seven SW1736 cell lines as well as four recombinant L2 and four MH3924A cell lines were established by neomycin selection. They were studied for hTPO expression using an antibody-based luminescence kit, followed by determination of the enzyme activity in the guaiacol assay and of the iodide uptake capacity in the presence of Na{sup 125}I. Genetically modified cell lines expressed up to 1,800 times more hTPO as compared to wild type tumour cells. The level of hTPO expression varied significantly between individual neomycin-resistant cell lines, suggesting that the recombinant retroviral DNA was integrated at different sites of the cellular genome. The accumulation of iodide, however, was not significantly enhanced in individual recombinant cell lines, irrespective of low or high hTPO expression. Moreover, there was no correlation between hTPO expression and enzyme activity in individual cell lines. The transduction of the hTPO gene per se is not sufficient to restore iodide trapping in non-iodide-concentrating tumour cells. Future

  20. A Selective Iodide Ion Sensor Electrode Based on Functionalized ZnO Nanotubes

    OpenAIRE

    Magnus Willander; Zafar Hussain Ibupoto; Kimleang Khun

    2013-01-01

    In this research work, ZnO nanotubes were fabricated on a gold coated glass substrate through chemical etching by the aqueous chemical growth method. For the first time a nanostructure-based iodide ion selective electrode was developed. The ZnO nanotubes were functionalized with miconazole ion exchanger and the electromotive force (EMF) was measured by the potentiometric method. The iodide ion sensor exhibited a linear response over a wide range of concentrations (1 × 10−6 to 1 × 10−1 M) and ...

  1. Tris(1,2-dimethoxyethane-κ2O,O′iodidocalcium iodide

    Directory of Open Access Journals (Sweden)

    Siou-Wei Ou

    2012-02-01

    Full Text Available In the title complex, [CaI(C4H10O23]I, the CaII atom is seven-coordinated by six O atoms from three 1,2-dimethoxyethane (DME ligands and one iodide anion in a distorted pentagonal–bipyramidal geometry. The I atom and one of the O atoms from a DME ligand lie in the axial positions while the other O atoms lie in the basal plane. The other iodide anion is outside the complex cation.

  2. Efficiency enhancement in dye sensitized solar cells using gel polymer electrolytes based on a tetrahexylammonium iodide and MgI2 binary iodide system.

    Science.gov (United States)

    Bandara, T M W J; Dissanayake, M A K L; Jayasundara, W J M J S R; Albinsson, I; Mellander, B-E

    2012-06-28

    Quasi-solid-state dye-sensitized solar cells have drawn the attention of scientists and technologists as a potential candidate to supplement future energy needs. The conduction of iodide ions in quasi-solid-state polymer electrolytes and the performance of dye sensitized solar cells containing such electrolytes can be enhanced by incorporating iodides having appropriate cations. Gel-type electrolytes, based on PAN host polymers and mixture of salts tetrahexylammonium iodide (Hex4N(+)I(-)) and MgI2, were prepared by incorporating ethylene carbonate and propylene carbonate as plasticizers. The salt composition in the binary mixture was varied in order to optimize the performance of solar cells. The electrolyte containing 120% Hex4N(+)I(-) with respect to weight of PAN and without MgI2 showed the highest conductivity out of the compositions studied, 2.5 × 10(-3) S cm(-1) at 25 °C, and a glass transition at -102.4 °C. However, the electrolyte containing 100% Hex4N(+)I(-) and 20% MgI2 showed the best solar cell performance highlighting the influence of the cation on the performance of the cell. The predominantly ionic behaviour of the electrolytes was established from the dc polarization data and all the electrolytes exhibit iodide ion transport. Seven different solar cells were fabricated employing different electrolyte compositions. The best cell using the electrolyte with 100% Hex4N(+)I(-) and 20% MgI2 with respect to PAN weight showed 3.5% energy conversion efficiency and 8.6 mA cm(-2) short circuit current density.

  3. Combustion and inorganic bromine emission of waste printed circuit boards in a high temperature furnace

    International Nuclear Information System (INIS)

    Highlights: ► The combustion efficiency of waste printed circuit boards (PCBs) depends on temperature, excess air factor, and high temperature zone residence time. Temperature has the most significant impact. Under the proposed condition, combustion of waste PCBs alone is quite complete within the furnace. ► High temperature prompts a more complete bromine release and conversion. When temperature is high enough, 99.9% organobrominated compounds, the potential precursors for brominated dixoins formation, are destroyed efficiently and convert to inorganic bromine in flue gas, as HBr and Br2. ► Temperature has crucial influence over the inhibition of HBr conversion to Br2, while the oxygen partial pressure plays a reverse role in the conversion to a very small extent. Increasing temperature will decrease the volume percentage ratio of Br2/HBr in flue gas greatly. ► The thermodynamic equilibrium approach of bromine conversion was investigated. The two forms of inorganic bromine in flue gas substantially reach thermodynamic equilibrium within 0.25 s. Under the proposed operating condition, the reaction of Br transfer and conversion finish. - Abstract: High temperature combustion experiments of waste printed circuit boards (PCBs) were conducted using a lab-scale system featuring a continuously-fed drop tube furnace. Combustion efficiency and the occurrence of inorganic bromine (HBr and Br2) were systematically studied by monitoring the main combustion products continuously. The influence of furnace temperature (T) was studied from 800 to 1400 °C, the excess air factor (EAF) was varied from 1.2 to 1.9 and the residence time in the high temperature zone (RTHT) was set at 0.25, 0.5, or 0.75 s. Combustion efficiency depends on temperature, EAF and RTHT; temperature has the most significant effect. Conversion of organic bromine from flame retardants into HBr and Br2 depends on temperature and EAF. Temperature has crucial influence over the ratio of HBr to Br2

  4. Studying Equilibrium in the Chemical Reaction between Ferric and Iodide Ions in Solution Using a Simple and Inexpensive Approach

    Science.gov (United States)

    Nikolaychuk, Pavel Anatolyevich; Kuvaeva, Alyona Olegovna

    2016-01-01

    A laboratory experiment on the study of the chemical equilibrium based on the reaction between ferric and iodide ions in solution with the formation of ferrous ions, free iodine, and triiodide ions is developed. The total concentration of iodide and triiodide ions in the reaction mixture during the reaction is determined by the argentometric…

  5. Analysis of iodide and iodate in Lake Mead, Nevada using a headspace derivatization gas chromatography-mass spectrometry.

    Science.gov (United States)

    Dorman, James W; Steinberg, Spencer M

    2010-02-01

    We report here a derivatization headspace method for the analysis of inorganic iodine in water. Samples from Lake Mead, the Las Vegas Wash, and from Las Vegas tap water were examined. Lake Mead and the Las Vegas Wash contained a mixture of both iodide and iodate. The average concentration of total inorganic iodine (TII) for Lake Mead was approximately 90 nM with an iodide-to-iodate ratio of approximately 1. The TII concentration (approximately 160 nM) and the ratio of iodide to iodate were higher for the Las Vegas Wash (approximately 2). The TII concentration for tap water was close to that of Lake Mead (approximately 90 nM); however, tap water contained no detectable iodide as a result of ozonation and chlorine treatment which converts all of the iodide to iodate. PMID:19184627

  6. Hydroxylated polybrominated diphenyl ethers exhibit different activities on thyroid hormone receptors depending on their degree of bromination

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Xiao-Min, E-mail: rxm200318@gmail.com; Guo, Liang-Hong, E-mail: LHGuo@rcees.ac.cn; Gao, Yu, E-mail: francesscototti@gmail.com; Zhang, Bin-Tian, E-mail: nktianster@gmail.com; Wan, Bin, E-mail: binwan@rcees.ac.cn

    2013-05-01

    Polybrominated diphenyl ethers (PBDEs) have been shown to disrupt thyroid hormone (TH) functions in experimental animals, and one of the proposed disruption mechanisms is direct binding of hydroxylated PBDE (OH-PBDE) to TH receptors (TRs). However, previous data on TH receptor binding and TH activity of OH-PBDEs were very limited and sometimes inconsistent. In the present paper, we examined the binding potency of ten OH-PBDEs with different degrees of bromination to TR using a fluorescence competitive binding assay. The results showed that the ten OH-PBDEs bound to TR with potency that correlated to their bromination level. We further examined their effect on TR using a coactivator binding assay and GH3 cell proliferation assay. Different TR activities of OH-PBDEs were observed depending on their degree of bromination. Four low-brominated OH-PBDEs (2′-OH-BDE-28, 3′-OH-BDE-28, 5-OH-BDE-47, 6-OH-BDE-47) were found to be TR agonists, which recruited the coactivator peptide and enhanced GH3 cell proliferation. However, three high-brominated OH-PBDEs (3-OH-BDE-100, 3′-OH-BDE-154, 4-OH-BDE-188) were tested to be antagonists. Molecular docking was employed to simulate the interactions of OH-PBDEs with TR and identify the structural determinants for TR binding and activity. According to the docking results, low-brominated OH-PBDEs, which are weak binders but TR agonists, bind with TR at the inner side of its binding pocket, whereas high-brominated compounds, which are potent binders but TR antagonists, reside at the outer region. These results indicate that OH-PBDEs have different activities on TR (agonistic or antagonistic), possibly due to their different binding geometries with the receptor. - Highlights: ► Thyroid hormone (TH) activity of OH-PBDEs with different Br number was evaluated. ► Four different experimental approaches were employed to investigate the mechanism. ► Low-brominated OH-PBDEs were agonists, but high-brominated ones were antagonists.

  7. Iodide-induced thyrotoxicosis in a thyroidectomized patient with metastatic thyroid carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Yoshinari, M.; Tokuyama, T.; Okamura, K.; Sato, K.; Kusuda, K.; Fujishima, M.

    1988-04-15

    An unusual case of iodide-induced thyrotoxicosis is documented in this article. The patient was a 64-year-old euthyroid man with acromegaly. He also had multiple follicular and papillary thyroid carcinomas with a metastatic lesion in the lumbar vertebrae. After a total thyroidectomy, he became slightly hypothyroid, and the lumbar lesion began to incorporate /sup 131/I by scintigraphy. When an iodine-containing contrast medium happened to be injected, a transient increase of serum thyroid hormone level was observed. After complete thyroid ablation with 83 mCi of /sup 131/I, the oral administration of 100 mg of potassium iodide for 7 days induced a prominent increase of serum thyroid hormone level. These findings indicated that the metastatic thyroid carcinoma could produce excess thyroid hormone insofar as a sufficient amount of iodide was given. Although this is the first report of such a case, iodide-induced thyrotoxicosis may not be rare in patients with thyroid carcinomas because the Wolff-Chaikoff effect is thought to be lost, and the organic iodinating activity and lysosomal protease activity are well-preserved.

  8. Reductive degradation of perfluoroalkyl compounds with aquated electrons generated from iodide photolysis at 254 nm

    OpenAIRE

    Park, Hyunwoong; vecitis, Chad D.; Cheng, Jie; Dalleska, Nathan F; Mader, Brian T.; Hoffmann, Michael R.

    2011-01-01

    The perfluoroalkyl compounds (PFCs), perfluoroalkyl sulfonates (PFXS) and perfluoroalkyl carboxylates (PFXA) are environmentally persistent and recalcitrant towards most conventional water treatment technologies. Here, we complete an in depth examination of the UV-254 nm production of aquated electrons during iodide photolysis for the reductive defluorination of six aquated perfluoroalkyl compounds (PFCs) of various headgroup and perfluorocarbon tail length. Cyclic voltammograms (CV) show tha...

  9. The sodium iodide symporter (NIS) and potential regulators in normal, benign and malignant human breast tissue.

    LENUS (Irish Health Repository)

    Ryan, James

    2011-01-01

    The presence, relevance and regulation of the Sodium Iodide Symporter (NIS) in human mammary tissue remains poorly understood. This study aimed to quantify relative expression of NIS and putative regulators in human breast tissue, with relationships observed further investigated in vitro.

  10. Relaxation of the Silver/Silver Iodide Electrode in Aqueous Solution

    NARCIS (Netherlands)

    Peverelli, K.J.

    1979-01-01

    The aim of this study is to detect and characterize relaxation processes on silver/silver iodide electrodes in aqueous electrolyte solution. The information obtained is to be used for an estimation of the consequences of similar processes on colloidal AgI particles during encounter.In chapter 1 a ge

  11. LIQUID-CRYSTALLINE AND THERMOCHROMIC BEHAVIOR OF 4-SUBSTITUTED 1-METHYLPYRIDINIUM IODIDE SURFACTANTS

    NARCIS (Netherlands)

    NUSSELDER, JJH; ENGBERTS, JBFN; VANDOREN, HA

    1993-01-01

    The mesogenic behaviour of a series of thirty-one 1-alkyl-4-(or 2-)alkyl-pyridinium salts and of a homologous series of four 1-methyl-4-n-alkoxycarbonylpyridinium iodides is described. The occurrence and stability range of the thermotropic phases depend dramatically on the structure of the surfactan

  12. Theoretical calculations of primary particle condensation for cadmium and caesium iodide vapours

    International Nuclear Information System (INIS)

    This report considers a model of aerosol nucleation from the vapour phase which has been developed by Buckle. The applicability of the model has been tested by considering the condensation of caesium iodide and cadmium vapours under a wide variety of pre-mixed flow conditions of interest to PWR severe accident studies. (U.K.)

  13. Photodissociation of sodium iodide and resonant ionization of sodium atom produced

    Institute of Scientific and Technical Information of China (English)

    HUO Bing-hai; Z.T.Salim; A.H.Bakery

    2004-01-01

    Resonant ionization spectroscopy (RIS) and resonant ionization mass spectroscopy (RIMS) are employed to detect the photodissociation product of sodium iodide molecules in a molecular beam in an intense laser field in the absence of the buffer gases. Time of flight mass spectra is recorded. In particular, the appearances of multiphoton ionization are discussed.

  14. Regioselective iodination of aromatic compounds with potassium iodide in the presence of benzyltriphenylphosphonium perchlorate

    Institute of Scientific and Technical Information of China (English)

    Jalal Albadi; Masoumeh Abedini; Nasir Iravani

    2012-01-01

    A simple and efficient method for the selective iodination of various aromatic compounds by using potassium iodide in the presence of benzyltriphenylphosphonium perchlorate,is reported.This method provides several advantages such as good selectivity between ortho and para positions of aromatic compounds and high yields of the products.

  15. Kinetic modeling of the purging of activated carbon after short term methyl iodide loading

    International Nuclear Information System (INIS)

    A bimolecular reaction model containing the physico-chemical parameters of the adsorption and desorption was developed earlier to describe the kinetics of methyl iodide retention by activated carbon adsorber. Both theoretical model and experimental investigations postulated constant upstream methyl iodide concentration till the maximum break-through. The work reported here includes the extension of the theoretical model to the general case when the concentration of the challenging gas may change in time. The effect of short term loading followed by purging with air, and an impulse-like increase in upstream gas concentration has been simulated. The case of short term loading and subsequent purging has been experimentally studied to validate the model. The investigations were carried out on non-impregnated activated carbon. A 4 cm deep carbon bed had been challenged by methyl iodide for 30, 90, 120 and 180 min and then purged with air, downstream methyl iodide concentration had been measured continuously. The main characteristics of the observed downstream concentration curves (time and slope of break-through, time and amplitude of maximum values) showed acceptable agreement with those predicted by the model

  16. Ammonium-iodide route to anhydrous EuI2:mechanism and preparation

    Institute of Scientific and Technical Information of China (English)

    刁成鹏; 余金秋; 李红卫; 彭鹏; 吴浩; 何华强; 颜世宏; 胡运生

    2015-01-01

    Anhydrous EuI2 is an essential raw material for novel Eu2+-doped halide scintillators such as SrI2:Eu, CsBa2I5:Eu and BaBrI:Eu. An efficient and economic method to produce high purity anhydrous EuI2 is critical for future development and applications of these scintillators. In this paper, the ammonium-iodide route to anhydrous EuI2 was investigated, and anhydrous EuI2 with purity of 99.95 wt.%was successfully prepared. The dehydration mechanisms of europium iodide hydrate and its mixture with NH4I were comparatively investigated by X-ray diffraction (XRD), thermal analysis and fluorescence spectroscopy. The thermal decomposition process of individual europium iodide hydrate was revealed as follows:EuI3·9H2O→EuI3·8H2O→EuI3·7H2O→EuI2·H2O→EuI2, and the hydrolysis mechanism of europium hydrate was comprehensively studied. When europium iodide hydrate was dehydrated with NH4I, NH4Eu2I5 formed as an intermediate product, and the hydrolysis of EuI2 was effectively restrained. The role of NH4I as an io-dination agent was also discussed.

  17. Leaching of iodide (I(-)) and iodate (IO3(-)) anions from synthetic layered double hydroxide materials.

    Science.gov (United States)

    Theiss, Frederick L; Ayoko, Godwin A; Frost, Ray L

    2016-09-15

    Several studies have previously demonstrated that layered double hydroxides (LDHs) show considerable potential for the adsorption of radioiodine from aqueous solution; however, few studies have demonstrated that these materials are able to store radioactive (131)I for an acceptable period. The leaching of iodide (I(-)) and iodate (IO3(-)) form Mg/Al LDHs has been carried out. Contact time appeared to be a more significant variable for the leaching of iodate (IO3(-)) compared to that of iodide (I(-)). Experimental results are fitted to the pseudo second order model, suggesting that diffusion is likely to be the rate-limiting step. The presence of carbonate in the leaching solution appeared to significantly increase the leaching of iodide (I(-)) as did the presence of chloride to a lesser extent. The maximum amount of iodate (IO3(-)) leached using ultrapure water as the leaching solution was 21% of the iodate (IO3(-)) originally present. The corresponding result for iodide (I(-)) was even lower at 3%. PMID:27309951

  18. Activation of lactoperoxidase by heme-linked protonation and heme-independent iodide binding.

    Science.gov (United States)

    Toyama, Akira; Tominaga, Aya; Inoue, Tatsuo; Takeuchi, Hideo

    2010-01-01

    Lactoperoxidase (LPO), a mammalian secretory heme peroxidase, catalyzes the oxidation of thiocyanate by hydrogen peroxide to produce hypothiocyanate, an antibacterial agent. Although LPO is known to be activated at acidic pH and in the presence of iodide, the structural basis of the activation is not well understood. We have examined the effects of pH and iodide concentration on the catalytic activity and the structure of LPO. Electrochemical and colorimetric assays have shown that the catalytic activity is maximized at pH 4.5. The heme Soret absorption band exhibits a small red-shift at pH 5.0 upon acidification, which is ascribable to a structural transition from a neutral to an acidic form. Resonance Raman spectra suggest that the heme porphyrin core is slightly contracted and the Fe-His bond is strengthened in the acidic form compared to the neutral form. The structural change of LPO upon activation at acidic pH is similar to that observed for myeloperoxidase, another mammalian heme peroxidase, upon activation at neutral pH. Binding of iodide enhances the catalytic activity of LPO without affecting either the optimum pH of activity or the heme structure, implying that the iodide binding occurs at a protein site away from the heme-linked protonation site.

  19. Iodide accumulation provides kelp with an inorganic antioxidant impacting atmospheric chemistry

    Science.gov (United States)

    Küpper, Frithjof C.; Carpenter, Lucy J.; McFiggans, Gordon B.; Palmer, Carl J.; Waite, Tim J.; Boneberg, Eva-Maria; Woitsch, Sonja; Weiller, Markus; Abela, Rafael; Grolimund, Daniel; Potin, Philippe; Butler, Alison; Luther, George W.; Kroneck, Peter M. H.; Meyer-Klaucke, Wolfram; Feiters, Martin C.

    2008-01-01

    Brown algae of the Laminariales (kelps) are the strongest accumulators of iodine among living organisms. They represent a major pump in the global biogeochemical cycle of iodine and, in particular, the major source of iodocarbons in the coastal atmosphere. Nevertheless, the chemical state and biological significance of accumulated iodine have remained unknown to this date. Using x-ray absorption spectroscopy, we show that the accumulated form is iodide, which readily scavenges a variety of reactive oxygen species (ROS). We propose here that its biological role is that of an inorganic antioxidant, the first to be described in a living system. Upon oxidative stress, iodide is effluxed. On the thallus surface and in the apoplast, iodide detoxifies both aqueous oxidants and ozone, the latter resulting in the release of high levels of molecular iodine and the consequent formation of hygroscopic iodine oxides leading to particles, which are precursors to cloud condensation nuclei. In a complementary set of experiments using a heterologous system, iodide was found to effectively scavenge ROS in human blood cells. PMID:18458346

  20. Preparation and Luminescence Thermochromism of Tetranuclear Copper(I)-Pyridine-Iodide Clusters

    Science.gov (United States)

    Parmeggiani, Fabio; Sacchetti, Alessandro

    2012-01-01

    A simple and straightforward synthesis of a tetranuclear copper(I)-pyridine-iodide cluster is described as a laboratory experiment for advanced inorganic chemistry undergraduate students. The product is used to demonstrate the fascinating and visually impressive phenomenon of luminescence thermochromism: exposed to long-wave UV light, the…

  1. Experimental study on iodine chemistry (EXSI) - Containment experiments with methyl iodide

    Energy Technology Data Exchange (ETDEWEB)

    Holm, J.; Ekberg, C. (Chalmers Univ. of Technology, Goeteborg (Sweden)); Kaerkelae, T.; Auvinen, A. (VTT, Espoo (Finland)); Glaenneskog, H. (Vattenfall Power Consultant, Goeteborg (Sweden))

    2011-05-15

    An experimental study on radiolytic decomposition of methyl iodide was conducted in co-operation between VTT and Chalmers University of Technology as a part of the NKS-R programs. In year 2008 the NROI project, a Nordic collaboration studying iodine chemistry in the containment, was started. During year 2008 (NROI-1) the radiolytic oxidation of elemental iodine was investigated and during 2009 (NROI-2), the radiolytic oxidation of organic iodine was studied. This project (NROI-3) is a continuation of the investigation of the oxidation of organic iodine. The project has been divided into two parts. 1. The aims of the first part were to investigate the effect of ozone and UV-radiation, in dry and humid conditions, on methyl iodide. 2. The second project was about gamma radiation (approx20 kGy/h) and methyl iodide in dry and humid conditions. 1. Experimental results showed that the methyl iodide concentration in the facility was reduced with increasing temperature and increasing UV-radiation intensity. Similar behaviour occurred when ozone was present in the system. Formed organic gas species during the decomposition of methyl iodide was mainly formaldehyde and methanol. The particle formation was instant and extensive when methyl iodide was exposed to ozone and/or radiation at all temperatures. The size of the formed primary particles was about 10 nm and the size of secondary particles was between 50-200 nm. From the SEM-EDX analyses of the particles, the conclusion was drawn that these were some kind of iodine oxides (I{sub xO{sub y}). However, the correct speciation of the formed particles was difficult to obtain because the particles melted and fused together under the electron beam. 2. The results from this sub-project are more inconsistent and hard to interpret. The particle formation was significant lesser than corresponding experiments when ozone/UV-radiation was used instead of gamma radiation. The transport of gaseous methyl iodide through the facility was

  2. The effect of representing bromine from VSLS on the simulation and evolution of Antarctic ozone

    Science.gov (United States)

    Oman, Luke D.; Douglass, Anne R.; Salawitch, Ross J.; Canty, Timothy P.; Ziemke, Jerald R.; Manyin, Michael

    2016-09-01

    We use the Goddard Earth Observing System Chemistry-Climate Model, a contributor to both the 2010 and 2014 World Meteorological Organization Ozone Assessment Reports, to show that inclusion of 5 parts per trillion (ppt) of stratospheric bromine (Bry) from very short lived substances (VSLS) is responsible for about a decade delay in ozone hole recovery. These results partially explain the significantly later recovery of Antarctic ozone noted in the 2014 report, as bromine from VSLS was not included in the 2010 Assessment. We show multiple lines of evidence that simulations that account for VSLS Bry are in better agreement with both total column BrO and the seasonal evolution of Antarctic ozone reported by the Ozone Monitoring Instrument on NASA's Aura satellite. In addition, the near-zero ozone levels observed in the deep Antarctic lower stratospheric polar vortex are only reproduced in a simulation that includes this Bry source from VSLS.

  3. Stratospheric ozone depletion and future levels of atmospheric chlorine and bromine

    Science.gov (United States)

    Prather, Michael J.; Watson, Robert T.

    1990-01-01

    The rise in atmospheric chlorine levels caused by the emission of chlorofluorocarbons and other halocarbons is thought to be the main cause of the appearance of the Antarctic ozone 'hole' in the late 1970s, and the more modest ozone depletion observed over parts of the Northern Hemisphere. Atmospheric bromine, also associated with halocarbon emissions, is believed to contribute to ozone depletion. Over the next decade, further increases in these compounds are inevitable. Model calculations show that by the end of the next century, atmospheric chlorine and bromine levels may return to those prevalent before the onset of the ozone hole, but only if more stringent regulations are applied to halocarbon production than those currently proposed.

  4. Formation pathways of brominated products from benzophenone-4 chlorination in the presence of bromide ions

    Institute of Scientific and Technical Information of China (English)

    Ming Xiao; Dongbin Wei; Liping Li; Qi Liu; Huimin Zhao; Yuguo Du

    2014-01-01

    The brominated products,formed in chlorination treatment of benzophenone-4 in the presence of bromide ions,were identified,and the formation pathways were proposed.Under disinfection conditions,benzophenone-4 would undertake electrophilic substitution generating mono-or di-halogenated products,which would be oxidized to esters and further hydrolyzed to phenol derivatives.The generated catechol intermediate would be transformed into furan-like heterocyclic product.The product species were pH-dependent,while benzophenone-4 ehmination was chlorine dose-dependent.When the chlorination treatment was performed on ambient water spiked with benzophenone-4 and bromide ions,most of brominated byproducts could be detected,and the acute toxicity significantly increased as well.

  5. Co-doping of Potassium and Bromine in Carbon Nanotubes: A Density Functional Theory Study

    Institute of Scientific and Technical Information of China (English)

    XIAO Yong; YAN xiao-Hong; DING Jian-Wen

    2007-01-01

    We investigate the co-doping of potassium and bromine in singlewalled carbon nanotubes (SWCNTs)and doublewalled carbon nanotubes(DWCNTs)based on density functional theory.In the co-doped(6,O)SWCNTs,the 4s electron of potassium is transferred to nanotube and Br,leading to the n-type feature of SWCNTs.When potassium is intercalated into inner tube and bromine is put on outer tube,the positive and negative charges reside on the outer and inner tubes of the(7.0)@(16,0)DWCNT,respectively.It is expected that DWCNTs would be an ideal candidate for p-n junction and diode applications.

  6. Occupational exposure to brominated flame retardants : With emphasis on polybrominated diphenyl ethers

    OpenAIRE

    Thuresson, Kaj

    2004-01-01

    Brominated flame retardants (BFRs) are a diverse group of chemicals, which are used to slow down or inhibit the development of fires. BFRs are incorporated into a wide range of consumer products that are considered as potential fire hazards, such as TV-sets, household appliances, computers, and textiles. The production and use of BFRs is extensive and consists of mainly tetrabromobisphenol A (TBBPA), polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecan (HBCD). BFRs in general, but...

  7. Ship-source pollution by polychlorinated biphenyls and brominated flame retardants

    OpenAIRE

    ČULIN, Jelena; Bielić, Toni

    2015-01-01

    Polychlorinated biphenyls (PCBs) and brominated flame retardants (BFRs) are groups of anthropogenic contaminants that have been routinely used in many applications for several decades. Prior to the discovery of their detrimental health effects and subsequent implementation of regulatory measures they were widely applied in shipbuilding. They are still found onboard active and inactive ships and pose a risk to human and environment. Therefore, it is important to continue to carry out preven...

  8. A comparison of the virucidal properties of chlorine, chlorine dioxide, bromine chloride and iodine.

    OpenAIRE

    Taylor, G R; Butler, M

    1982-01-01

    Chlorine dioxide, bromine chloride and iodine were compared with chlorine as virucidal agents. Under optimal conditions all disinfectants were effective at low concentrations, but each disinfectant responded differently to acidity and alkalinity. Disinfection by chlorine was impaired by the presence of ammonia, but the other disinfectants retained much of their potency. Disinfection of poliovirus by iodine resulted in structural changes in the virions as seen by electron micrroscopy, but the ...

  9. Bromine monoxide / sulphur dioxide ratios in relation to volcanological observations at Mt. Etna 2006–2009

    OpenAIRE

    N. Bobrowski; Giuffrida, G

    2012-01-01

    Over a 3-yr period, from 2006 to 2009, frequent scattered sunlight DOAS measurements were conducted at Mt. Etna at a distance of around 6 km downwind from the summit craters. During the same period and in addition to these measurements, volcanic observations were made by regularly visiting various parts of Mt. Etna. Here, results from these measurements and observations are presented and their relation is discussed. The focus of the investigation is the bromine monoxide/sulphur dioxide (BrO ...

  10. Mercury oxidation from bromine chemistry in the free troposphere over the southeastern US

    OpenAIRE

    S. Coburn; Dix, B.; Edgerton, E.; Holmes, C. D; Kinnison, D.; Liang, Q; A. ter Schure; Wang, S.; R. Volkamer

    2015-01-01

    The elevated deposition of atmospheric mercury over the Southeastern United States is currently not well understood. Here we measure partial columns and vertical profiles of bromine monoxide (BrO) radicals, a key component of mercury oxidation chemistry, to better understand the processes and altitudes at which mercury is being oxidized in the atmosphere. We use the data from a ground-based MAX-DOAS instrument located at a coastal site ~ 1 km from the Gulf o...

  11. Tropospheric bromine chemistry: implications for present and pre-industrial ozone and mercury

    Directory of Open Access Journals (Sweden)

    J. P. Parrella

    2012-04-01

    Full Text Available We present a new model for the global tropospheric chemistry of inorganic bromine (Bry coupled to oxidant-aerosol chemistry in the GEOS-Chem chemical transport model (CTM. Sources of tropospheric Bry include debromination of sea-salt aerosol, photolysis and oxidation of short-lived bromocarbons, and transport from the stratosphere. Comparison to a GOME-2 satellite climatology of tropospheric BrO columns shows that the model can reproduce the observed increase of BrO with latitude, the northern mid-latitudes maximum in winter, and the Arctic maximum in spring. This successful simulation is contingent on the HOBr + HBr reaction taking place in aqueous aerosols and ice clouds. Bromine chemistry in the model decreases tropospheric ozone concentrations by <1−8 nmol mol−1 (6.5% globally, with the largest effects in the northern extratropics in spring. The global mean tropospheric OH concentration decreases by 4%. Inclusion of bromine chemistry improves the ability of global models (GEOS-Chem and p-TOMCAT to simulate observed 19th-century ozone and its seasonality. Bromine effects on tropospheric ozone are comparable in the present-day and pre-industrial atmospheres so that estimates of anthropogenic radiative forcing are minimally affected. Br atom concentrations are 40% higher in the pre-industrial atmosphere due to lower ozone, which would decrease by a factor of 2 the atmospheric lifetime of elemental mercury against oxidation by Br. This suggests that historical anthropogenic mercury emissions may have mostly deposited to northern mid-latitudes, enriching the corresponding surface reservoirs. The persistent rise in background surface ozone at northern mid-latitudes during the past decades could possibly contribute to the observations of elevated mercury in subsurface waters of the North Atlantic.

  12. Tropospheric bromine chemistry: implications for present and pre-industrial ozone and mercury

    Directory of Open Access Journals (Sweden)

    J. P. Parrella

    2012-08-01

    Full Text Available We present a new model for the global tropospheric chemistry of inorganic bromine (Bry coupled to oxidant-aerosol chemistry in the GEOS-Chem chemical transport model (CTM. Sources of tropospheric Bry include debromination of sea-salt aerosol, photolysis and oxidation of short-lived bromocarbons, and transport from the stratosphere. Comparison to a GOME-2 satellite climatology of tropospheric BrO columns shows that the model can reproduce the observed increase of BrO with latitude, the northern mid-latitudes maximum in winter, and the Arctic maximum in spring. This successful simulation is contingent on the HOBr + HBr reaction taking place in aqueous aerosols and ice clouds. Bromine chemistry in the model decreases tropospheric ozone mixing ratios by <1–8 nmol mol−1 (6.5% globally, with the largest effects in the northern extratropics in spring. The global mean tropospheric OH concentration decreases by 4%. Inclusion of bromine chemistry improves the ability of global models (GEOS-Chem and p-TOMCAT to simulate observed 19th-century ozone and its seasonality. Bromine effects on tropospheric ozone are comparable in the present-day and pre-industrial atmospheres so that estimates of anthropogenic radiative forcing are minimally affected. Br atom concentrations are 40% higher in the pre-industrial atmosphere due to lower ozone, which would decrease by a factor of 2 the atmospheric lifetime of elemental mercury against oxidation by Br. This suggests that historical anthropogenic mercury emissions may have mostly deposited to northern mid-latitudes, enriching the corresponding surface reservoirs. The persistent rise in background surface ozone at northern mid-latitudes during the past decades could possibly contribute to the observations of elevated mercury in subsurface waters of the North Atlantic.

  13. Toxicity of brominated flame retardants with focus on retinoid system disturbances

    OpenAIRE

    Litens Karlsson, Sabina

    2015-01-01

    Background: Brominated flame retardants (BFR) are detected in the environment and biota all over the world. They contribute to the human body burden of industrial chemicals and exposure is mainly via food. Indoor dust contributes substantially in some exposure situations, which involve small children. Regulatory restrictions and bans have been introduced as some BFRs can impact proper development, potentially via the endocrine system. Objectives: The study aim was to clarify the role of...

  14. Bromine-catalyzed conversion of CO2 and epoxides to cyclic carbonates under continuous flow conditions.

    Science.gov (United States)

    Kozak, Jennifer A; Wu, Jie; Su, Xiao; Simeon, Fritz; Hatton, T Alan; Jamison, Timothy F

    2013-12-11

    A continuous method for the formation of cyclic carbonates from epoxides and carbon dioxide (CO2) is described. The catalysts used are inexpensive and effective in converting the reagents to the products in a residence time (t(R)) of 30 min. The cyclic carbonate products are obtained in good to excellent yield (51-92%). On the basis of a series of kinetics experiments, we propose a reaction mechanism involving epoxide activation by electrophilic bromine and CO2 activation by an amide.

  15. Detailed modeling of the atmospheric degradation mechanism of very-short lived brominated species

    OpenAIRE

    G. Krysztofiak; Catoire, Valéry; Poulet, G.; Marécal, V.; Pirre, Michel; Louis, F.; Canneaux, S.; B. Josse

    2012-01-01

    International audience Detailed chemical reaction schemes for the atmospheric degradations of the very short-lived species (VSLS) bromoform (CHBr3) and dibromomethane (CH2Br2) have been established. These degradation schemes have been implemented in the meteorological/tracer transport model CATT-BRAMS used in the present case as pseudo one-dimensional model with chemistry of CH4, CO, HOx, NOx, NOy and Ox. They include the main possible reactions of the intermediate brominated peroxy radica...

  16. Brominated and organophosphate flame retardants in selected consumer products on the Japanese market in 2008

    Energy Technology Data Exchange (ETDEWEB)

    Kajiwara, Natsuko, E-mail: kajiwara.natsuko@nies.go.jp [Research Center for Material Cycles and Waste Management, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506 (Japan); Noma, Yukio; Takigami, Hidetaka [Research Center for Material Cycles and Waste Management, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, Ibaraki 305-8506 (Japan)

    2011-09-15

    Highlights: {yields} We examined the flame retardants in electronics, curtains, wallpaper and insulator. {yields} Use of alternative brominated and organophosphate flame retardants was suggested. {yields} All the products investigated also contained PBDEs, TBBPA and polybromophenols. {yields} Incorporation of recycled materials containing hazardous substance was suggested. - Abstract: The concentrations of traditional brominated flame retardants (BFRs) and organophosphate flame retardants (OPFRs) in new consumer products, including electronic equipment, curtains, wallpaper, and building materials, on the Japanese market in 2008 were investigated. Although some components of the electronic equipment contained bromine at concentrations on the order of percent by weight, as indicated by X-ray fluorescence analysis, the bromine content could not be fully accounted for by the BFRs analyzed in this study, which included polybrominated diphenylethers, decabromodiphenyl ethane, tetrabromobisphenol A, polybromophenols, and hexabromocyclododecanes. These results suggest the use of alternative BFRs such as newly developed formulations derived from tribromophenol, tetrabromobisphenol A, or both. Among the 11 OPFRs analyzed, triphenylphosphate was present at the highest concentrations in all the products investigated, which suggests the use of condensed-type OPFRs as alternative flame retardants, because they contain triphenylphosphate as an impurity. Tripropylphosphate was not detected in any samples; and trimethylphosphate, tributyl tris(2-butoxyethyl)phosphate, and tris(1,3-dichloro-2-propyl)phosphate were detected in only some components and at low concentrations. Note that all the consumer products evaluated in this study also contained traditional BFRs in amounts that were inadequate to impart flame retardancy, which implies the incorporation of recycled plastic materials containing BFRs that are of global concern.

  17. Reactive airways dysfunction and systemic complaints after mass exposure to bromine.

    OpenAIRE

    Woolf, A; Shannon, M.

    1999-01-01

    Occasionally children are the victims of mass poisoning from an environmental contaminant that occurs due to an unexpected common point source of exposure. In many cases the contaminant is a widely used chemical generally considered to be safe. In the following case, members of a sports team visiting a community for an athletic event were exposed to chemicals while staying at a local motel. Bromine-based sanitizing agents and other chemicals such as hydrochloric acid, which were used in exces...

  18. Interactions of bromine, chlorine, and iodine photochemistry during ozone depletions in Barrow, Alaska

    OpenAIRE

    Thompson, C. R.; P. B. Shepson; Liao, J.; Huey, L.G.; E. C. Apel; Cantrell, C. A.; Flocke, F.; Orlando, J.; Fried, A.; Hall, S. R; R. S. Hornbrook; D. J. Knapp; Mauldin III, R. L; Montzka, D. D.; B. C. Sive

    2014-01-01

    The springtime depletion of tropospheric ozone in the Arctic is known to be caused by active halogen photochemistry resulting from halogen atom precursors emitted from snow, ice, or aerosol surfaces. The role of bromine in driving ozone depletion events (ODEs) has been generally accepted, but much less is known about the role of chlorine radicals in ozone depletion chemistry. While the potential impact of iodine in the High Arctic is more uncertain, there ha...

  19. Interactions of bromine, chlorine, and iodine photochemistry during ozone depletions in Barrow, Alaska

    OpenAIRE

    Thompson, C. R.; P. B. Shepson; Liao, J.; Huey, L.G.; E. C. Apel; Cantrell, C. A.; Flocke, F.; Orlando, J.; Fried, A.; Hall, S. R; R. S. Hornbrook; D. J. Knapp; Mauldin III, R. L; Montzka, D. D.; B. C. Sive

    2015-01-01

    The springtime depletion of tropospheric ozone in the Arctic is known to be caused by active halogen photochemistry resulting from halogen atom precursors emitted from snow, ice, or aerosol surfaces. The role of bromine in driving ozone depletion events (ODEs) has been generally accepted, but much less is known about the role of chlorine radicals in ozone depletion chemistry. While the potential impact of iodine in the High Arctic is more uncertain, there have been indicatio...

  20. Brominated and organophosphate flame retardants in selected consumer products on the Japanese market in 2008

    International Nuclear Information System (INIS)

    Highlights: → We examined the flame retardants in electronics, curtains, wallpaper and insulator. → Use of alternative brominated and organophosphate flame retardants was suggested. → All the products investigated also contained PBDEs, TBBPA and polybromophenols. → Incorporation of recycled materials containing hazardous substance was suggested. - Abstract: The concentrations of traditional brominated flame retardants (BFRs) and organophosphate flame retardants (OPFRs) in new consumer products, including electronic equipment, curtains, wallpaper, and building materials, on the Japanese market in 2008 were investigated. Although some components of the electronic equipment contained bromine at concentrations on the order of percent by weight, as indicated by X-ray fluorescence analysis, the bromine content could not be fully accounted for by the BFRs analyzed in this study, which included polybrominated diphenylethers, decabromodiphenyl ethane, tetrabromobisphenol A, polybromophenols, and hexabromocyclododecanes. These results suggest the use of alternative BFRs such as newly developed formulations derived from tribromophenol, tetrabromobisphenol A, or both. Among the 11 OPFRs analyzed, triphenylphosphate was present at the highest concentrations in all the products investigated, which suggests the use of condensed-type OPFRs as alternative flame retardants, because they contain triphenylphosphate as an impurity. Tripropylphosphate was not detected in any samples; and trimethylphosphate, tributyl tris(2-butoxyethyl)phosphate, and tris(1,3-dichloro-2-propyl)phosphate were detected in only some components and at low concentrations. Note that all the consumer products evaluated in this study also contained traditional BFRs in amounts that were inadequate to impart flame retardancy, which implies the incorporation of recycled plastic materials containing BFRs that are of global concern.

  1. On bromine, nitrogen oxides and ozone depletion in the tropospheric plume of Erebus volcano (Antarctica)

    OpenAIRE

    Boichu, Marie; Oppenheimer, Clive; Roberts, Tjarda J.; V. I. Tsanev; Kyle, Philip R

    2011-01-01

    International audience Since the discovery of bromine oxide (BrO) in volcanic emissions, there has been speculation concerning its role in chemical evolution and notably ozone depletion in volcanic plumes. We report the first measurements using Differential Optical Absorption Spectroscopy (DOAS) of BrO in the tropospheric plume of the persistently degassing Erebus volcano (Antarctica). These are the first observations pertaining to emissions from an alkaline phonolitic magma. The observed ...

  2. Thermal Recycling of Brominated Flame Retardants with Fe2O3.

    Science.gov (United States)

    Altarawneh, Mohammednoor; Ahmed, Oday H; Jiang, Zhong-Tao; Dlugogorski, Bogdan Z

    2016-08-01

    Plastics containing brominated flame retardants (BFRs) constitute the major fraction of nonmetallic content in e-waste. Co-pyrolysis of BFRs with hematite (Fe2O3) represents a viable option for the thermal recycling of BFRs. Consensus of experimental findings confirms the excellent bromine fixation ability of Fe2O3 and the subsequent formation of iron bromides. This contribution provides a comprehensive mechanistic account of the primary reactions between a cluster model of Fe2O3 and major bromine-bearing products from the decomposition of tetrabromobisphenol A (TBBA), the most commonly deployed BFR. We estimate the thermo-kinetic parameters for interactions of Fe2O3 with HBr, brominated alkanes and alkenes, bromobenzene, and bromophenol. Dissociative addition of HBr at a Fe-O bond proceeds through a trivial barrier of 8.2 kcal/mol with fitted parameters in the Arrhenius equation of k(T) = 7.96 × 10(11) exp(-6400/RT) s(-1). The facile and irreversible nature for HBr addition to Fe2O3 accords with the experimentally reported 90% reduction in HBr emission when Fe2O3 interacts with TBBA pyrolysates. A detailed kinetic analysis indicates that, transformation of Fe2O3 into iron bromides and oxybromides occurs via successive addition of HBr to Fe(Br)-O(H) entities. Elimination of a water molecule proceeds through an intramolecular H transfer. A direct elimination one-step mechanism operates in the dehydrohalogenation of bromoethane into ethene over Fe2O3. Dissociative decomposition and direct elimination channels assume comparable reaction rates in formation of acetylene from vinyl bromide. Results from this study provide an atomic-based insight into a promising thermal recycling route of e-waste. PMID:27366936

  3. Conversion of Iodide to Hypoiodous Acid and Molecular Iodine at the Air-Water Interface

    Science.gov (United States)

    Pillar, E. A.; Guzman, M. I.

    2013-12-01

    Sea spray aerosols continuously transfer a significant amount of halides to the marine boundary layer, where they play a major role in the depletion of tropospheric ozone. The reactivity of iodide is of special interest in sea spray aerosols, where this species is enriched relative to chloride and bromide in surface seawater. This work presents laboratory experiments that provide mechanistic information to understand the reactivity of halides in atmospheric aerosols. Pneumatically assisted electrospray is used to aerosolize solutions of sodium iodide (0.01-100 μM), which are rapidly (~3 μs) oxidized by ozone at 25 °C. Reaction products include HIO, IO2-, IO3-, I2, HI2O-, and I3-, all identified by mass spectrometry. The distribution of products varies along two different reaction pathways, one favoring the production of I2 and HIO for typical tropospheric ozone levels (~50 ppbv), and another one directed to the production of IO3- at higher oxidizer concentrations. The formation of products increases exponentially with rising concentrations of initial sodium iodide, [NaI]0. The process is determined to be pH independent for the pH range 6-8 representative of surface waters. The substitution of aqueous solutions by organic solvents, such as methanol or acetonitrile, causes a decrease in the surface tension and lifetime of the droplets, leading to larger I2 production. The presence of surface active organic compounds, which alter the structure of the interfacial region, promote the pathway of I2 formation over IO3-. In conclusion, this presentation will show how the oxidation of iodide in aqueous microdroplets can release reactive gas-phase species, such as I2 and HIO, capable to affect tropospheric ozone globally. Normalized intensity of products observed during the ozonolysis of iodide solutions at 130 ppbv ozone. Cone voltage = 70 V, needle voltage = 2.5 kV.

  4. [The application of eosin and propidium iodide in evaluation of vitality of human spermatozoa].

    Science.gov (United States)

    Ploskonos, М В

    2014-11-01

    The article analyzes comparative assessment of vitality of spermatozoa by condition of permeability of membranes for eosin and propidium iodide and comparison of results acquired using technique of light and fluorescent microscopy. The comparison of data of light microscopy with eosin staining with data of fluorescent microscopy with propidium iodide staining demonstrated that percentage of content of spermatozoa separated from ejaculates of 28 fertile males and stained with eosin was reliably higher (34.8 ± 3.2) than percentage of content of spermatozoa with stained with propidium iodide (2.1 ± 4.0). After incubation of spermatozoa under room temperature during 24 hours percentage of unviable cells with stained eosin also was higher than in case of propidium iodide staining correspondingly (44.5 ± 3.3% and 34.7 ± 3.6%). The analysis of vitality of spermatozoa under damaging effect of oxidative stress on cell membrane developed by 4 hours incubation with 200 mkM of hydrogen peroxide (H2O2) demonstrated that under staining of spermatozoa with propidium iodide significantly higher percentage of damaged cells is detected. In such cases, eosin staining is less suitable for detection of vitality of spermatozoa (73.6 ± 5.8% against 51.7 ± 6.4%). The carried out experiment demonstrates that in case of detected effects on spermatozoa (for example, effect of oxidative stress) the light microscopy insufficiently adequate reflects degree of damage of membranes of spermatozoa. The fluorescent microscopy detects a higher percentage of spermatozoa with damaged membrane.

  5. Brominating activity of the seaweed Ascophyllum nodosum: Impact on the biosphere

    Energy Technology Data Exchange (ETDEWEB)

    Wever, R.; Tromp, M.G.M.; Krenn, B.E.; Marjani, A.; Van Tol, M. (Univ. of Amsterdam (Netherlands))

    1991-03-01

    Macroalgae are an important source of volatile halogenated organic compounds, such as bromoform and dibromomethane. The mechanism by which these compounds are formed is still elusive. The authors report that the brown seaweeds Laminaria saccharina, Laminaria digitata, Fucus vesiculosis, Pelvetia canaliculata, and Ascophyllum nodosum and the red seaweeds Chondrus crispus and Plocamium hamatum contain bromoperoxidases. The intact plants are able to brominate exogeneous organic compounds when H{sub 2}O{sub 2} and Br{sup {minus}} are added to seawater. Further, the authors show that the brominating activity of the brown macroalga A. nodosum, which contains a vanadium bromoperoxidase located on the thallus surface, occurs when the plant is exposed to light and not in the dark. The rate of bromination of exogenous organic compounds in seawater by this plant is 68 nmol (g of wet alga){sup {minus}1} h{sup {minus}1}. HOBr is a strong biocidal agent and the authors propose that the formation of HOBr by this seaweed is part of a host defense system.

  6. Discrimination of hexabromocyclododecane from new polymeric brominated flame retardant in polystyrene foam by nuclear magnetic resonance.

    Science.gov (United States)

    Jeannerat, Damien; Pupier, Marion; Schweizer, Sébastien; Mitrev, Yavor Nikolaev; Favreau, Philippe; Kohler, Marcel

    2016-02-01

    Hexabromocyclododecane (HBCDD) is a brominated flame retardant (BFR) and major additive to polystyrene foam thermal insulation that has recently been listed as a persistent organic pollutant by the Stockholm Convention. During a 2013/2014 field analytical survey, we measured HBCDD content ranging from 0.2 to 2.4% by weight in 98 polystyrene samples. Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) analyses indicated that expandable (EPS) and extruded (XPS) polystyrene foams significantly differed in the α/γ HBCDD isomer ratio, with a majority of α and γ isomers in XPS and EPS, respectively. Interestingly, this technique indicated that some recent materials did not contain HBCDD, but demonstrated bromine content when analysed with X-ray fluorescence (XRF). Further investigation by Nuclear Magnetic Resonance (NMR) was able to discriminate between the BFRs present. In addition to confirming the absence or presence of HBCDD in polystyrene samples, high-field NMR spectroscopy provided evidence of the use of brominated butadiene styrene (BBS) as copolymer in the production of polystyrene. Use of this alternative flame retardant is expected to cause fewer health and environmental concerns. Our results highlight a trend towards the use of copolymerized BFRs as an alternative to HBCDD in polystyrene foam boards. In addition to providing a rapid NMR method to identify polymeric BFR, our analytical approach is a simple method to discriminate between flame-retardants in polystyrene foam insulating materials.

  7. Heterogeneous processing of bromine compounds by atmospheric aerosols: Relation to the ozone budget

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, J.M.; Henson, B.F.; Dubey, M.K.; Casson, J.L.; Johal, M.S. [Los Alamos National Lab., NM (US); Wilson, K.R. [Univ. of California, Berkeley, CA (US)

    1998-11-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). The depletion of ozone, particularly above Antarctica, has been investigated extensively to formulate public policy on the use of halocarbons. While it has been shown that heterogeneous reactions of chlorine compounds on stratospheric particulates cause the ozone hole, little is known of the analogous bromine mechanisms, even though it has been recognized for two decades that catalytic destruction of ozone by bromine could be more efficient than chlorine. Furthermore, field measurements and modeling calculations suggest that these heterogeneous (gas/surface) reactions are not restricted to the Antarctic regions but occur globally. The authors have performed laboratory measurements of the uptake of bromine compounds and other halogens on simulated stratospheric aerosols to help elucidate their role in catalytic ozone destruction cycles. Their studies contribute to the data base required to make assessments of the effects of human activities on global change, including the Montreal Protocol.

  8. Effects of Assistant Solvents and Mixing Intensity on the Bromination Process of Butyl Rubber

    Institute of Scientific and Technical Information of China (English)

    王伟; 邹海魁; 初广文; 向阳; 彭晗; 陈建峰

    2014-01-01

    A slow bromination process of butyl rubber (IIR) suffers from low efficiency and low selectivity (S) of target-product. To obtain suitable approach to intensify the process, effects of assistant solvents and mixing inten-sity on the bromination process were systemically studied in this paper. The reaction process was found constantly accelerated with the increasing dosage and polarity of assistant solvent. Hexane with 30%(by volume) dichloro-methane was found as the suitable solvent component, where the stable conversion of 1,4-isoprene transferring to target product (xA1s) of 80.2%and the corresponding S of 91.2%were obtained in 5 min. The accelerated reaction process was demonstrated being remarkably affected by mixing intensity until the optimal stirring rate of 1100 r·min-1 in a stirred tank reactor. With better mixing condition, a further intensification of the process was achieved in a ro-tating packed bed (RPB) reactor, where xA1s of 82.6% and S of 91.9% were obtained in 2 min. The usage of the suitable solvent component and RPB has potential application in the industrial bromination process intensification.

  9. Monitoring of WEEE plastics in regards to brominated flame retardants using handheld XRF.

    Science.gov (United States)

    Aldrian, Alexia; Ledersteger, Alfred; Pomberger, Roland

    2015-02-01

    This contribution is focused on the on-site determination of the bromine content in waste electrical and electronic equipment (WEEE), in particular waste plastics from television sets (TV) and personal computer monitors (PC) using a handheld X-ray fluorescence (XRF) device. The described approach allows the examination of samples in regards to the compliance with legal specifications for polybrominated biphenyls (PBBs) and polybrominated diphenyl ethers (PBDEs) directly after disassembling and facilitates the sorting out of plastics with high contents of brominated flame retardants (BFRs). In all, over 3000 pieces of black (TV) and 1600 pieces of grey (PC) plastic waste were analysed with handheld XRF technique for this study. Especially noticeable was the high percentage of pieces with a bromine content of over 50,000ppm for TV (7%) and PC (39%) waste plastics. The applied method was validated by comparing the data of handheld XRF with results obtained by GC-MS. The results showed the expected and sufficiently accurate correlation between these two methods. It is shown that handheld XRF technique is an effective tool for fast monitoring of large volumes of WEEE plastics in regards to BFRs for on-site measurements. PMID:25464945

  10. A satellite based study of tropospheric bromine explosion events and their linkages to polar cyclone development

    Science.gov (United States)

    Blechschmidt, Anne-Marlene; Richter, Andreas; Burrows, John P.; Kaleschke, Lars; Strong, Kimberly; Theys, Nicolas; Weber, Mark; Zhao, Xiaoyi; Zien, Achim; Hodges, Kevin I.

    2016-04-01

    Intense, cyclone-like shaped plumes of tropospheric bromine monoxide (BrO) are regularly observed by the UV-vis satellite instruments GOME-2/MetOp-A and SCIAMACHY/Envisat over Arctic and Antarctic sea ice in polar spring. The plumes are associated with an autocatalytic chemical chain reaction involving tropospheric ozone depletion and initiated by the release of bromine from cold brine-covered ice or snow to the atmosphere. This influences atmospheric chemistry as it affects the oxidising capacity of the troposphere through OH production and may also influence the local weather/temperature of the polar atmosphere, as ozone is a major greenhouse gas. Here, we make combined use of satellite retrievals and numerical model simulations to study individual BrO plume cases in the polar atmosphere. In agreement with previous studies, our analysis shows that the plumes are often transported by high latitude cyclones, sometimes over several days despite the short atmospheric lifetime of BrO. Moreover, general characteristics of bromine explosion events linked to transport by polar weather systems, such as frequency, spatial distribution and favourable weather conditions are derived based on a new detection method. Our results show that BrO cyclone transport events are by far more common in the Antarctic than in the Arctic.

  11. Effect of Bromine Substitution on Human Dermal Absorption of Polybrominated Diphenyl Ethers.

    Science.gov (United States)

    Abdallah, Mohamed Abou-Elwafa; Pawar, Gopal; Harrad, Stuart

    2015-09-15

    Human dermal absorption of eight mono- to deca-brominated diphenyl ethers (PBDEs) was investigated for the first time using EPISKIN human skin equivalent tissue. Using a standard in vitro protocol, EPISKIN tissues mounted in specially designed diffusion cells were exposed to the target PBDEs for 24 h. Estimated steady-state flux (Jss) and permeation coefficients (Papp) across the skin increased with decreasing bromine substitution from BDE-153 (Papp = 4.0 × 10(-4) cm/h) to BDE-1 (Papp = 1.1 × 10(-2) cm/h). This was accompanied by an increase in the time required to traverse the skin tissue into the receptor fluid (lag time) from 0.25 h for BDE-1 to 1.26 h for BDE-153. Papp values for the studied PBDEs were correlated significantly (P water solubility and log KOW. While less brominated congeners achieved faster dermal penetration, higher PBDEs displayed greater accumulation within the skin tissue. The PBDEs thus accumulated represent a contaminant depot from which they may be slowly released to the systemic circulation over a prolonged period. Maximal percutaneous penetration was observed for BDE-1 (∼ 30% of the applied 500 ng/cm(2) dose). Interestingly, BDE-183 and BDE-209 showed very low dermal absorption, exemplified by a failure to reach the steady state within the 24 h exposure period that was studied. PMID:26301594

  12. Bromine recovery in residual solutions generated in the 15 N isotopic determination methodology (Rittenberg, 1946)

    International Nuclear Information System (INIS)

    The isotopic determination of 15 N (Rittenberg, 1946) is a methodology used in the Laboratory of Isotope Stable (CENA/USP). In this procedure, in the oxidation of nitrogen species for N2, solution of Li Br O is used, generating as residue 50 L y-1 of solution contends Li Br and Li Br O. Seeking to recover the bromine contained in that residue, very toxic substance, a special line was built composed by reaction balloons (1 and 2 liters), addition funnel, gas flow regulator and connections in glass. In the system proposed, after the acidification (sulfuric acid) of the alkaline residual solution, the liberated bromine (Br2) it was then dragged by flow of nitrogen and reacted with solution of LiOH. That reaction facilitated the production of Li Br O in solution (Efficiency = 82±2%), that was reused later on same analytic procedure. The high cost of the liquid bromine is another attractiveness that corroborates the employment of the developed procedure. They took place isotopic determinations using the recovered solutions and prepared, and the observed values didn't show statistical difference (T test of Student). The presented procedure is part of the Management Program of Chemical Residues of CENA/USP, which seeks to destine the residues of responsibility of the institution appropriately, forming professionals to the practices of environmental management. (author)

  13. Discrimination of hexabromocyclododecane from new polymeric brominated flame retardant in polystyrene foam by nuclear magnetic resonance.

    Science.gov (United States)

    Jeannerat, Damien; Pupier, Marion; Schweizer, Sébastien; Mitrev, Yavor Nikolaev; Favreau, Philippe; Kohler, Marcel

    2016-02-01

    Hexabromocyclododecane (HBCDD) is a brominated flame retardant (BFR) and major additive to polystyrene foam thermal insulation that has recently been listed as a persistent organic pollutant by the Stockholm Convention. During a 2013/2014 field analytical survey, we measured HBCDD content ranging from 0.2 to 2.4% by weight in 98 polystyrene samples. Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) analyses indicated that expandable (EPS) and extruded (XPS) polystyrene foams significantly differed in the α/γ HBCDD isomer ratio, with a majority of α and γ isomers in XPS and EPS, respectively. Interestingly, this technique indicated that some recent materials did not contain HBCDD, but demonstrated bromine content when analysed with X-ray fluorescence (XRF). Further investigation by Nuclear Magnetic Resonance (NMR) was able to discriminate between the BFRs present. In addition to confirming the absence or presence of HBCDD in polystyrene samples, high-field NMR spectroscopy provided evidence of the use of brominated butadiene styrene (BBS) as copolymer in the production of polystyrene. Use of this alternative flame retardant is expected to cause fewer health and environmental concerns. Our results highlight a trend towards the use of copolymerized BFRs as an alternative to HBCDD in polystyrene foam boards. In addition to providing a rapid NMR method to identify polymeric BFR, our analytical approach is a simple method to discriminate between flame-retardants in polystyrene foam insulating materials. PMID:26492426

  14. Computer simulation of the cluster destruction of stratospheric ozone by bromine

    Institute of Scientific and Technical Information of China (English)

    A.E.Galashev; O.R.Rakhmanova

    2012-01-01

    The interaction of (Br-)i(H2O)50-i,0≤i≤6 clusters with oxygen and ozone molecules is investigated by the method of molecular dynamics simulation.The ozone molecules as well as the bromine ions do not leave the cluster during the calculation of 25 ps.The ability of the cluster containing molecular oxygen to absorb the infrared (IR)radiation is reduced in the frequency range of 0 ≤ ω ≤ 3500 cm-1 when the number of the bromine ions in the cluster grows.The intensity of the Raman spectrum is not changed significantly when the Br-ions are added to the ozonecontaining system.The power of the emitted IR radiation is increased when the number of bromine ions grows in the oxygen-containing system.The data obtained in this study on the IR and the Raman spectra of the water clusters that contain ozone,oxygen,and Br-can be used to develop an investigation of the mechanisms of ozone depletion.

  15. Mechanochemical conversion of brominated POPs into useful oxybromides: a greener approach

    Science.gov (United States)

    Cagnetta, Giovanni; Liu, Han; Zhang, Kunlun; Huang, Jun; Wang, Bin; Deng, Shubo; Wang, Yujue; Yu, Gang

    2016-06-01

    Brominated organic pollutants are considered of great concern for their adverse effect on human health and the environment, so an increasing number of such compounds are being classified as persistent organic pollutants (POPs). Mechanochemical destruction is a promising technology for POPs safe disposal because it can achieve their complete carbonization by solvent-free high energy ball milling at room temperature. However, a large amount of co-milling reagent usually is necessary, so a considerable volume of residue is produced. In the present study a different approach to POPs mechanochemical destruction is proposed. Employing stoichiometric quantities of Bi2O3 or La2O3 as co-milling reagent, brominated POPs are selectively and completely converted into their corresponding oxybromides (i.e. BiOBr and LaOBr), which possess very peculiar properties and can be used for some actual and many more potential applications. In this way, bromine is beneficially reused in the final product, while POPs carbon skeleton is safely destroyed to amorphous carbon. Moreover, mechanochemical destruction is employed in a greener and more sustainable manner.

  16. Computer simulation of the cluster destruction of stratospheric ozone by bromine

    International Nuclear Information System (INIS)

    The interaction of (Br−)i(H2O)50−i, 0 ≤ i ≤ 6 clusters with oxygen and ozone molecules is investigated by the method of molecular dynamics simulation. The ozone molecules as well as the bromine ions do not leave the cluster during the calculation of 25 ps. The ability of the cluster containing molecular oxygen to absorb the infrared (IR) radiation is reduced in the frequency range of 0 ≤ ω ≤ 3500 cm−1 when the number of the bromine ions in the cluster grows. The intensity of the Raman spectrum is not changed significantly when the Br− ions are added to the ozone-containing system. The power of the emitted IR radiation is increased when the number of bromine ions grows in the oxygen-containing system. The data obtained in this study on the IR and the Raman spectra of the water clusters that contain ozone, oxygen, and Br− can be used to develop an investigation of the mechanisms of ozone depletion

  17. MISCIBILITY AND MORPHOLOGY OF THIN FILMS OF BLENDS OF POLYSTYRENE WITH BROMINATED POLYSTYRENES: EFFECTS OF VARYING THE MOLECULAR WEIGHT,BROMINATION DEGREE AND ANNEALING

    Institute of Scientific and Technical Information of China (English)

    Rui Song; De-bin Yang; Ling-hao He; Guang-tao Yao

    2006-01-01

    Thin films of incompatible polymer blends can form a variety of structures during preparation and subsequent annealing process. For the polymer blend system consisting of polystyrene and poly(styrene-co-p-bromo-styrene), I.e.,PS/PBrxS, its compatibility could be adjusted by varying the degree of bromination and the molecular weight of both components comprised. In this paper, surface chemical compositions of the cast and the annealing films were investigated by X-ray photoelectron spectroscopy (XPS) and contact angle measurement; meanwhile, surface topographical changes are followed by atomic force microscopy (AFM). In addition, substantial attention was paid to the effect of annealing on the morphologic variations induced by phase separation and/or dewetting of the thin film. Moreover, the influences of the molecular weight, Mw, as well as the brominated degree, x%, on the sample surface are explored systematically, and the corresponding observations are explained in virtue of the Flory-Huggins theory, along with the dewetting of the polymer thin film.

  18. Synergistic Effect of Azadirachta Indica Extract and Iodide Ions on the Corrosion Inhibition of Aluminium in Acid Media

    International Nuclear Information System (INIS)

    The synergistic action caused by iodide ions on the corrosion inhibition of aluminium (Al) in 0.5 M HCl in the presence of Azadirachta Indica (AZI) plant extract has been investigated using potintiodynamic polarization and impedance techniques. It is found that AZI extract inhibits the corrosion of aluminium in 0.5 M HCl. The inhibition efficiency increases with the increase in AZI extract concentration, until 24% v/v of AZI extract, then Inh.% is decreased with father increase in AZI extract concentration. The adsorption of this extract in the studied concentration is found to obey Frewendlish adsorption isotherm. The addition of iodide ions enhances the inhibition efficiency to a considerable extent. The increase in Inh.% values in presence of fixed concentration of iodide ions indicates that AZI extract forms an insoluble complex at lower AZI extract concentrations by undergoing a joint adsorption. But at higher concentrations of AZI extract, competitive adsorption is found between iodide ions and the formed complex leading to less Inh.%. The Inh.% decreased in presence of iodide ions with AZI extract than in presence of AZI extract alone at all studied iodide concentrations. The synergism parameter S θ is defined and calculated from surface coverage values. This parameter in the case of AZI extract is found to be more than unity, indicating that the enhanced inhibition efficiency caused by the addition of iodide ions

  19. Contrasting the surface ocean distribution of bromoform and methyl iodide; implications for boundary layer physics, chemistry and climate

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, C J, E-mail: carl.j.palmer@gmail.co [Department of Oceanography, University of Cape Town, 7701 (South Africa)

    2010-08-15

    Bromoform and methyl iodide are both methane-like hydrocarbons with a halogen atom replacing one or more of the hydrogen atoms. Both of these compounds occur naturally in the environment as a result of their production from seaweed and kelp. They are of interest to climate science as a result of their catalytic destruction of boundary layer ozone (a potent greenhouse gas) and, specifically for methyl iodide, the proposed role in the formation of new cloud condensation nuclei with implications for climate. In this paper, the currently available data on the distribution of bromoform and methyl iodide are analysed and contrasted to show that the concentrations of bromoform and methyl iodide do not correlate, that, in contrast to bromoform, the parameterization of sea surface methyl iodide concentrations demands only the sea surface temperature, and that the pelagic distribution of methyl iodide appears to follow the solar zenith angle. These three observations together suggest that, while the pelagic source of bromoform is mostly biogenic, the source of methyl iodide is photochemical. This has implications for the understanding of planetary boundary layer chemistry and potential organohalogen mediated feedbacks to climate.

  20. Contrasting the surface ocean distribution of bromoform and methyl iodide; implications for boundary layer physics, chemistry and climate

    International Nuclear Information System (INIS)

    Bromoform and methyl iodide are both methane-like hydrocarbons with a halogen atom replacing one or more of the hydrogen atoms. Both of these compounds occur naturally in the environment as a result of their production from seaweed and kelp. They are of interest to climate science as a result of their catalytic destruction of boundary layer ozone (a potent greenhouse gas) and, specifically for methyl iodide, the proposed role in the formation of new cloud condensation nuclei with implications for climate. In this paper, the currently available data on the distribution of bromoform and methyl iodide are analysed and contrasted to show that the concentrations of bromoform and methyl iodide do not correlate, that, in contrast to bromoform, the parameterization of sea surface methyl iodide concentrations demands only the sea surface temperature, and that the pelagic distribution of methyl iodide appears to follow the solar zenith angle. These three observations together suggest that, while the pelagic source of bromoform is mostly biogenic, the source of methyl iodide is photochemical. This has implications for the understanding of planetary boundary layer chemistry and potential organohalogen mediated feedbacks to climate.

  1. Bromine monoxide / sulphur dioxide ratios in relation to volcanological observations at Mt. Etna 2006–2009

    Directory of Open Access Journals (Sweden)

    G. Giuffrida

    2012-12-01

    Full Text Available Over a 3-yr period, from 2006 to 2009, frequent scattered sunlight DOAS measurements were conducted at Mt. Etna at a distance of around 6 km downwind from the summit craters. During the same period and in addition to these measurements, volcanic observations were made by regularly visiting various parts of Mt. Etna. Here, results from these measurements and observations are presented and their relation is discussed. The focus of the investigation is the bromine monoxide/sulphur dioxide (BrO / SO2 ratio, and its variability in relation to volcanic processes. That the halogen/sulphur ratio can serve as a precursor or indicator for the onset of eruptive activity was already proposed by earlier works (e.g. Noguchi and Kamiya 1963; Menyailov, 1975; Pennisi and Cloarec, 1998; Aiuppa et al., 2002. However, there is still a limited understanding today because of the complexity with which halogens are released, depending on magma composition and degassing conditions. Our understanding of these processes is far from complete, for example of the rate and mechanism of bubble nucleation, growth and ascent in silicate melts (Carroll and Holloway, 1994, the halogen vapour-melt partitioning and the volatile diffusivity in the melt (Aiuppa et al., 2009. With this study we aim to add one more piece to the puzzle of what halogen/sulphur ratios might tell about volcanic activities. Our data set shows an increase of the BrO / SO2 ratio several weeks prior to an eruption, followed by a decline before and during the initial phase of eruptive activities. Towards the end of activity or shortly thereafter, the ratio increases to baseline values again and remains more or less constant during quiet phases. To explain the observed evolution of the BrO / SO2 ratio, a first empirical model is proposed. This model suggests that bromine, unlike chlorine and fluorine, is less soluble in the magmatic melt than sulphur. By using the DOAS method to determine SO2, we actually

  2. Surface Snowpack Key to Bromine Activation in a Changing Arctic Environment

    Science.gov (United States)

    Pratt, Kerri; Custard, Kyle; Shepson, Paul; Douglas, Thomas; Pöhler, Denis; Stephan, General; Zielcke, Johannes; Simpson, William; Platt, Ulrich; von Glasow, Roland; Tanner, David; Huey, L. Gregory; Carlsen, Mark; Stirm, Brian

    2013-04-01

    Arctic sea ice is rapidly declining and transforming from a multiyear ice pack to thinner, more saline, seasonal ice, which has important implications for Arctic atmospheric composition. Following springtime polar sunrise, "ozone depletion events", attributed to bromine chemistry, lead to episodic decreases in lower tropospheric ozone concentrations to near zero, concurrent with mercury depletion and deposition. Despite our increasing understanding of the spatial variability of BrO and possible reaction pathways based on laboratory studies, important questions remain regarding the most efficient sources of and mechanisms for Arctic halogen activation. During the March-April 2012 BRomine, Ozone, and Mercury EXperiment (BROMEX) in Barrow, Alaska, outdoor chamber experiments with snow and ice samples were conducted. Ozone was added as the precursor oxidant, and the samples were investigated with and without ambient sunlight. Samples included first-year sea ice, brine icicles, several layers of snow above first-year sea ice, and seasonal snow above the tundra. Chemical ionization mass spectrometry was utilized to monitor Br2 production. Tundra snow and surface snow above sea ice produced the most Br2, with no production resulting from sea ice and basal snow directly above sea ice. Overall, the most efficient Br2 production was observed from snow samples characterized by lower pH and higher bromide/chloride ratios. Br2 was only observed in the presence of sunlight, indicating the role of snowpack photochemical reactions and the hydroxyl radical in its production. Br2 production via the surface snowpack explains previously-observed BrO enhancements above sea ice, as well as observations of inland tundra hotspots in measured BrO by aircraft-based nadir MAX-DOAS (Multi Axis-Differential Optical Absorption Spectroscopy) measurements, conducted during BROMEX. The findings indicate that atmospherically processed snow is likely a major source of Arctic bromine release, which

  3. Brominated flame retardants and organochlorine pollutants in eggs of little owls (Athene noctua) from Belgium

    Energy Technology Data Exchange (ETDEWEB)

    Jaspers, Veerle [Department of Biology, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk (Belgium); Covaci, Adrian [Toxicological Centre, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk (Belgium)]. E-mail: adrian.covaci@ua.ac.be; Maervoet, Johan [Toxicological Centre, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk (Belgium); Dauwe, Tom [Department of Biology, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk (Belgium); Voorspoels, Stefan [Toxicological Centre, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk (Belgium); Schepens, Paul [Toxicological Centre, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk (Belgium); Eens, Marcel [Department of Biology, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610 Wilrijk (Belgium)

    2005-07-15

    Residues of brominated diphenylethers (PBDEs), organochlorinated pesticides (OCPs) and polychlorinated biphenyls (PCBs) were measured in 40 eggs of little owls (Athene noctua), a terrestrial top predator from Belgium. The major organohalogens detected were PCBs (median 2,600 ng/g lipid, range 790-23000 ng/g lipid). PCB 153,138/163, 170, 180 and 187 were the predominant congeners and constituted 71% of total sum PCBs. PBDEs were measurable in all samples, but their concentrations were much lower than for PCBs, with a range from 29-572 ng/g lipid (median 108 ng/g lipid). The most prevalent PBDE congeners in little owl egg samples were BDE 47, 99 and 153. This profile differs from the profile in marine bird species, for which BDE 47 was the dominant congener, indicating that terrestrial birds may be more exposed to higher brominated BDE congeners than marine birds. The fully brominated BDE 209 could be detected in one egg sample (17 ng/g lipid), suggesting that higher brominated BDEs may accumulate in terrestrial food chains. Brominated biphenyl (BB) 153 was determined in all egg samples, with levels ranging from 0.6 to 5.6 ng/g lipid (median 1.3 ng/g lipid). Additionally, hexabromocyclododecane (HBCD) could be identified and quantified in only two eggs at levels of 20 and 50 ng/g lipid. OCPs were present at low concentrations, suggesting a rather low contamination of the sampled environment with OCPs (median concentrations of sum DDTs: 826 ng/g lipid, sum chlordanes: 1,016 ng/g lipid, sum HCHs: 273 ng/g lipid). Hexachlorobenzene (HCB) and octachlorostyrene (OCS) were also found at low median levels of 134 and 3.4 ng/g lipid, respectively. Concentrations of most analytes were significantly higher in eggs collected from deserted nests in comparison to addled (unhatched) eggs, while eggshell thickness did not differ between deserted and addled eggs. No significant correlations were found between eggshell thickness and the analysed organohalogens. - PBDEs are measurable

  4. Synthesis of cholesteryl-α-D-lactoside via generation and trapping of a stable β-lactosyl iodide

    Science.gov (United States)

    Davis, Ryan A.; Fettinger, James C.; Gervay-Hague, Jacquelyn

    2015-01-01

    The generation of β-lactosyl iodide was carried out under non-in situ-anomerization, metal free conditions by reacting commercially available β-per-O-acetylated lactose with trimethylsilyl iodide (TMSI). The β-iodide was surprisingly stable as evidenced by NMR spectroscopy. Introduction of octanol or cholesterol under microwave conditions gave high yields of α-linked glycoconjugates. Careful analysis of the reaction products and mechanistic considerations suggest an acid catalyzed rearrangement that provides α-linked glycosylation products with a free C2-hydroxyl. Accessibility to these compounds may further advance glycolipidomic profiling of immune modulating bacterial derived-glycans. PMID:26543257

  5. Part I. Voltammetric studies of potassium iodide at gold and platinum electrodes. Part II. Electrodeposition and characterization of poly(vinylferrocene) films

    Energy Technology Data Exchange (ETDEWEB)

    Holt, R.J.

    1993-01-01

    A mechanism for the adsorption of iodide on platinum and gold has been proposed in the literature which assumes hydrogen gas is evolved along with an adsorbed iodide atom. A rotating platinum ring-disk electrode was used here to detect the presence of any hydrogen produced upon iodide adsorption. No evidence for hydrogen formation was found. A gold-gold/platinum gas permeable double membrane electrode also did not show any evidence of hydrogen gas produced at gold during iodide adsorption. The voltammetry of iodide and iodate was examined using both gold and platinum ring-disk electrodes and a gas permeable double membrane electrode. The oxidation of adsorbed iodide was examined. The successful determination of the various oxidation states of iodide in acid media were performed: I[sub 2], IO[sup [minus

  6. Experimental study on iodine chemistry (EXSI) - Containment experiments with methyl iodide

    Energy Technology Data Exchange (ETDEWEB)

    Holm, J.; Glaenneskog, H.; Ekberg, C. (Chalmers Univ. of Technology (Sweden)); Kaerkelae, T.; Auvinen, A. (VTT Technical Research Centre of Finland (Finland))

    2010-05-15

    An experimental study on radiolytic decomposition of methyl iodide was conducted in co-operation between VTT and Chalmers University of Technology as a part of the NKS-R programs. The behaviour of iodine during a severe accident has been studied in several experimental programs, ranging from the large-scale PHEBUS FP tests and intermediate-scale ThAI tests to numerous separate effect studies. In year 2008 the NROI project, a Nordic collaboration studying iodine chemistry in the containment was started. During 2009, oxidation of iodine, especially organic iodine, was studied within the NROI project. The chemistry of organic iodine in the gas phase is still one of the greatest remaining uncertainties concerning iodine behaviour during a severe accident. During the first year of the NROI project the oxidation of elemental iodine, I2, with ozone and UV-light was investigated. In this study organic iodide, in this case methyl iodide, was investigated in similar conditions as in the NROI-1 project. The experimental facility applied in this study is based on the sampling system built at VTT for the ISTP project CHIP conducted by IRSN. The experimental facility and the measuring technology are sophisticated and unique in the area of nuclear research as well as in the field of aerosol science. Experimental results showed that the methyl iodide concentration in the facility was reduced with increasing temperature and increasing UVC intensity. Similar behaviour occurred when ozone was present in the system. Formed organic gas species during the decomposition of methyl iodide was mainly formaldehyde and methanol. Instant and extensive particle formation occurred when methyl iodide was transported through a UVC radiation field and/or when ozone was present. The size of the formed primary particles was about 10 nm and the size of secondary particles was between 50-150 nm. From the SEM-EDX analyses of the particles, the conclusion was drawn that these were some kind of iodine

  7. Reversible radiochromic plate based on polyvinyl alcohol-iodide complex containing silica nanoparticles

    International Nuclear Information System (INIS)

    A radiochromic plate based on a reversible change between iodide and iodine was prepared using a polyvinyl alcohol-iodide complex, silica nanoparticles, and agarose. X-ray (30 kV, 15 mA) irradiation of the plate changed it to a red color, which gradually disappeared and was completely erased within a day after stopping X-ray irradiation. The minimum detection dose was about 0.5 Gy for X-rays and 10 Gy for 137Cs γ-rays. The G-value for the oxidation of I- was estimated to be about 19.6 in a neutral solution and about 20.64 in an acidic solution. (author)

  8. Parametric study on removal efficiency of impregnated activated charcoal and silver zeolite for radioactive methyl iodide

    International Nuclear Information System (INIS)

    The removal efficiency of impregnated activated charcoal and silver zeolite for radioactive methyl iodide is influenced by various parameters such as temperature, relative humidity, face velocity and packing density. This study is to evaluate the dependency of the removal efficiency on each parameter and these combined parameters, quantitatively. Four types of adsorbents, BC-727, AgX, CHC-50 and SS 208C 5KI3, were tested. From experimental data and mass transfer theory, an experimental equation for evaluating the removal efficiency of adsorbents was derived under a series of experiments for radioactive methyl iodine-131. It was concluded that the removal efficiency calculated from the experimental equation agreed well with the experimental value. Effects of experimental specific parameters, such as Pre-flow time, methyl iodide injection time and After-flow time, on the removal efficiency of adsorbent are also described

  9. Iodide Recognition and Sensing in Water by a Halogen-Bonding Ruthenium(II)-Based Rotaxane.

    Science.gov (United States)

    Langton, Matthew J; Marques, Igor; Robinson, Sean W; Félix, Vítor; Beer, Paul D

    2016-01-01

    The synthesis and anion-recognition properties of the first halogen-bonding rotaxane host to sense anions in water is described. The rotaxane features a halogen-bonding axle component, which is stoppered with water-solubilizing permethylated β-cyclodextrin motifs, and a luminescent tris(bipyridine)ruthenium(II)-based macrocycle component. (1) H NMR anion-binding titrations in D2 O reveal the halogen-bonding rotaxane to bind iodide with high affinity and with selectively over the smaller halide anions and sulfate. The binding affinity trend was explained through molecular dynamics simulations and free-energy calculations. Photo-physical investigations demonstrate the ability of the interlocked halogen-bonding host to sense iodide in water, through enhancement of the macrocycle component's Ru(II) metal-ligand charge transfer (MLCT) emission. PMID:26626866

  10. Induction of iodide uptake in transformed thyrocytes: a compound screening in cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Froehlich, Eleonore [University of Tuebingen, Department of Endocrinology, Metabolism, Nephrology and Clinical Chemistry, Internal Medicine, Tuebingen (Germany); Brossart, Peter [University of Tuebingen, Department of Haematology, Oncology, Immunology and Rheumatology, Internal Medicine, Tuebingen (Germany); Wahl, Richard [University of Tuebingen, Department of Endocrinology, Metabolism, Nephrology and Clinical Chemistry, Internal Medicine, Tuebingen (Germany); Department IV, Internal Medicine, Tuebingen (Germany)

    2009-05-15

    Retinoic acid presently is the most advanced agent able to improve the efficacy of radioiodine therapy in differentiated thyroid carcinoma. In order to identify compounds with higher efficacy a panel of pharmacologically well-characterized compounds with antitumour action in solid cancer cell lines was screened. The effects of the compounds on iodide uptake, cell number, proliferation and apoptosis were evaluated. In general, compounds were more effective in cell lines derived from more aggressive tumours. The effectiveness in terms of number of responsive cell lines and maximal increase in iodide uptake achieved decreased in the order: APHA > valproic acid {approx} sirolimus {approx} arsenic trioxide > retinoic acid {approx} lovastatin > apicidine {approx} azacytidine {approx} retinol {approx} rosiglitazone {approx} bortezomib. We hypothesize that testing of cells from primary tumours or metastases in patients may be a way to identify compounds with optimum therapeutic efficacy for individualized treatment. (orig.)

  11. Gap energy studied by optical transmittance in lead iodide monocrystals grown by Bridgman's Method

    Directory of Open Access Journals (Sweden)

    Veissid N.

    1999-01-01

    Full Text Available The bandgap energy as a function of temperature has been determined for lead iodide. The monocrystal was obtained in a vacuum sealed quartz ampoule inside a vertical furnace by Bridgman's method. The optical transmittance measurement enables to evaluate the values of Eg. By a fitting procedure of Eg as a function of temperature is possible to extract the parameters that govern its behavior. The variation of Eg with temperature was determined as: Eg(T = Eg(0 - aT2/(a + T, with: Eg(0 = (2.435 ± 0.008 eV, a = (8.7 ± 1.3 x 10-4 eV/K and a = (192 ± 90 K. The bandgap energy of lead iodide at room temperature was found to be 2.277 ± 0.007 eV.

  12. Non-isothermal adsorption of radioactive methyl iodide at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Byung Seon; Park, Geun Il; Lee, Jung Won; Yoon, Ju Hyeon [KAERI, Taejon (Korea, Republic of); Yang, Ho Yeon [KHNPC, Taejon (Korea, Republic of); Ryu, Seung Kon [Chungnam National Univ., Taejon (Korea, Republic of)

    2003-07-01

    Although activated carbon has been successfully used in nuclear power plants, it cannot be considered as a primary adsorbent in a high temperature system, because of its low ignition temperature and its adverse reaction with nitrogen oxide. Therefore, activated carbon is virtually ruled out for high temperature operating systems. The adsorption and dynamic characteristics of gaseous methyl iodide for silver ion-exchanged zeolites at high temperatures up to 400 .deg. C was evaluated. In this study a simple nonisothermal and axially dispersed plug-flow was adopted to simulate the experimental breakthrough curves. The Langmuir-Freundlich isotherm model was used to represent the equilibrium relationship, and the linear driving force (LDF) approximation was used to represent the article uptake. From the viewpoint of silver utilization for the removal of methyl iodide, both the optimal operating temperature and the effective silver ion-exchange level were also determined.

  13. Performance of non-coconut base adsorbers in removal of iodine and organic iodides

    International Nuclear Information System (INIS)

    Systems for the removal of radioactive iodine and organic iodides have used impregnated coconut shell activated carbons almost exclusively. Coconut shell carbons have some disadvantages: their geographical origin determines their trace chemical content; pore structures and impregnant effectiveness are highly dependent on activation and impregnation techniques. The authors report laboratory performance of a group of iodine-organic iodide adsorbers using bases other than coconut shell carbon. These have been evaluated in conformity with USAEC Regulatory Guide 1.52 and RDT M16 1T. Performance with regard to 131I2 and CH3131I penetration and high-temperature elution have equaled or exceeded both the requirements of Guide 1.52 and results on typical coconut-shell carbons. Some performance outside Guide 1.52 ranges is included. Experimental problems in simulated LOCA testing are discussed. (U.S.)

  14. Heck Arylation of Acrylonitrile with Aryl Iodides Catalyzed by a Silica-bound Arsine Palladium(0) Complex

    Institute of Scientific and Technical Information of China (English)

    Ming Zhong CAI; Hong ZHAO; Rong Li ZHANG

    2005-01-01

    Acrylonitrile reacts with aryl iodides in the presence of tri-n-butylamine and a catalytic amount of a silica-bound arsine palladium(0) complex to afford stereoselectively (E)-cinnamonitriles in high yields.

  15. A mercuric ensemble based on a cycloruthenated complex as a visual probe for iodide in aqueous solution

    Science.gov (United States)

    Su, Xianlong; Guo, Lieping; Ma, Yajuan; Li, Xianghong

    2016-01-01

    A new water-soluble cycloruthenated complex Ru(bthiq)(dcbpy)2+ (1, Hbthiq = 1-(2-benzo[b]thiophenyl)isoquinoline, dcbpy = 4,4‧-dicarboxylate-2,2‧-bipyridine) was designed and synthesized to form its mercuric ensemble (1-Hg2+) to achieve visual detection of iodide anions. The binding constant of 1-Hg2+ is calculated to be 2.40 × 104 M-1, which is lower than that of HgI2. Therefore, the addition of I- to the aqueous solution of 1-Hg2+lead to significant color changes from yellow to deep-red by the release of 1. The results showed that iodide anions could be easily detected by the naked eyes. The detection limit of iodide anion is calculated as 0.77 μM. In addition, an easily-prepared test strip of 1-Hg2+ was obtained successfully to detect iodide anions.

  16. Cooperative effect of silver in copper-catalyzed trifluoromethylation of aryl iodides using Me3SiCF3

    KAUST Repository

    Weng, Zhiqiang

    2011-06-13

    An effective model of cooperative effect of silver for the coppercatalyzed trifluoromethylation of activated and unactivated aryl iodides to trifluoromethylated arenes using Me3SiCF3 was achieved with a broad substrate scope. © 2011 American Chemical Society.

  17. Furnace design for the mercuric iodide crystal growth for new semiconductor radiation detector

    International Nuclear Information System (INIS)

    Mercuric iodide has been attracted an interest for 40 years due to its efficiency as room temperature detector for X and γ-rays. It is worthy to note that commercial γ-ray detectors such as Ge semiconductor detectors should cool down to liquid nitrogen temperature. Compared to other semiconductor detectors such as CdZnTe and CdTe, mercuric iodide has higher efficiency, lower leakage current and less degradation. In addition, mercuric iodide has useful properties such as large band gap of 2.15 eV, low electron-hole pair creation energy of 4.2 eV, and high atomic number (Hg : 80 and I : 53). However, it is difficult to obtain high quality single crystals and the long term reliability problem in devices so that the applications of α-HgI2 are limited. Mercuric iodide undergoes a structural phase transition from an orthorhombic yellow phase (β-HgI2) to a tetragonal red phase (α-HgI2) at 127 .deg. C. In addition, the melting temperature of HgI2 is 259 .deg. C. Thus, when it grows through a melting method over 259 .deg. C, the β-HgI2 phase can be included in the final crystals in the room temperature. In general, in order to grow α-HgI2single crystals, the operating temperature is below 127 .deg. C. Note that the crystals from the solution method have contamination problems and the crystals from the physical vapor method usually display a higher quality with a well defined structure. A good thing for the physical vapor method is that α-HgI2 has high vapor pressure (∼0.1 Torr at 120 .deg. C) indicating that α-HgI2 can be grown in closed ampoules

  18. Nickel-catalyzed reductive arylation of activated alkynes with aryl iodides

    Science.gov (United States)

    Dorn, Stephanie C. M.; Olsen, Andrew K; Kelemen, Rachel E.; Shrestha, Ruja; Weix, Daniel J.

    2015-01-01

    The direct, regioselective, and stereoselective arylation of activated alkynes with aryl iodides using a nickel catalyst and manganese reductant is described. The reaction conditions are mild (40 °C in MeOH, no acid or base) and an intermediate organomanganese reagent is unlikely. Functional groups tolerated include halides and pseudohalides, free and protected anilines, and a benzyl alcohol. Other activated alkynes including an amide and a ketone also reacted to form arylated products in good yields. PMID:26028781

  19. Use of potassium iodide in Dermatology: updates on an old drug*

    OpenAIRE

    Costa, Rosane Orofino; de Macedo, Priscila Marques; Carvalhal, Aline; Bernardes-Engemann, Andréa Reis

    2013-01-01

    Potassium iodide, as a saturated solution, is a valuable drug in the dermatologist's therapeutic arsenal and is useful for the treatment of different diseases due to its immunomodulatory features. However, its prescription has become increasingly less frequent in dermatology practice. Little knowledge about its exact mechanism of action, lack of interest from the pharmaceutical industry, the advent of new drugs, and the toxicity caused by the use of high doses of the drug are some possible ex...

  20. Nitro-Grela-type complexes containing iodides - robust and selective catalysts for olefin metathesis under challenging conditions.

    Science.gov (United States)

    Tracz, Andrzej; Matczak, Mateusz; Urbaniak, Katarzyna; Skowerski, Krzysztof

    2015-01-01

    Iodide-containing nitro-Grela-type catalysts have been synthesized and applied to ring closing metathesis (RCM) and cross metathesis (CM) reactions. These new catalysts have exhibited improved efficiency in the transformation of sterically, non-demanding alkenes. Additional steric hindrance in the vicinity of ruthenium related to the presence of iodides ensures enhanced catalyst stability. The benefits are most apparent under challenging conditions, such as very low reaction concentrations, protic solvents or with the occurrence of impurities. PMID:26664602

  1. Peroxide effects of iodide excess on mitochondria in Fischer rat thyroid cell line in the early period

    Institute of Scientific and Technical Information of China (English)

    李敏

    2014-01-01

    Objective To investigate the peroxide effects of iodide excess on mitochondria in Fischer rat thyroid cell line(FRTL)in the early period.Methods After treatment with 0.0 mmol/L(control group)or 0.1 mmol/L potassium iodide(KI)for 2,4 and 24 h,respectively,changes of mitochondrial superoxide formation were assayed by flow cytometry and fluorescence microscopy using mitochondria-targeted hydroethidine(Mito SOX).

  2. Chlorine Dioxide-Iodide-Methyl Acetoacetate Oscillation Reaction Investigated by UV-Vis and Online FTIR Spectrophotometric Method

    OpenAIRE

    Laishun Shi; Xiaomei Wang; Na Li; Jie Liu; Chunying Yan

    2012-01-01

    In order to study the chemical oscillatory behavior and mechanism of a new chlorine dioxide-iodide ion-methyl acetoacetate reaction system, a series of experiments were done by using UV-Vis and online FTIR spectrophotometric method. The initial concentrations of methyl acetoacetate, chlorine dioxide, potassium iodide, and sulfuric acid and the pH value have great influence on the oscillation observed at wavelength of 289 nm. There is a preoscillatory or induction period, and the amplitude and...

  3. Nitro-Grela-type complexes containing iodides – robust and selective catalysts for olefin metathesis under challenging conditions

    Directory of Open Access Journals (Sweden)

    Andrzej Tracz

    2015-10-01

    Full Text Available Iodide-containing nitro-Grela-type catalysts have been synthesized and applied to ring closing metathesis (RCM and cross metathesis (CM reactions. These new catalysts have exhibited improved efficiency in the transformation of sterically, non-demanding alkenes. Additional steric hindrance in the vicinity of ruthenium related to the presence of iodides ensures enhanced catalyst stability. The benefits are most apparent under challenging conditions, such as very low reaction concentrations, protic solvents or with the occurrence of impurities.

  4. Nitro-Grela-type complexes containing iodides – robust and selective catalysts for olefin metathesis under challenging conditions

    Science.gov (United States)

    Tracz, Andrzej; Matczak, Mateusz; Urbaniak, Katarzyna

    2015-01-01

    Summary Iodide-containing nitro-Grela-type catalysts have been synthesized and applied to ring closing metathesis (RCM) and cross metathesis (CM) reactions. These new catalysts have exhibited improved efficiency in the transformation of sterically, non-demanding alkenes. Additional steric hindrance in the vicinity of ruthenium related to the presence of iodides ensures enhanced catalyst stability. The benefits are most apparent under challenging conditions, such as very low reaction concentrations, protic solvents or with the occurrence of impurities. PMID:26664602

  5. Nitro-Grela-type complexes containing iodides - robust and selective catalysts for olefin metathesis under challenging conditions.

    Science.gov (United States)

    Tracz, Andrzej; Matczak, Mateusz; Urbaniak, Katarzyna; Skowerski, Krzysztof

    2015-01-01

    Iodide-containing nitro-Grela-type catalysts have been synthesized and applied to ring closing metathesis (RCM) and cross metathesis (CM) reactions. These new catalysts have exhibited improved efficiency in the transformation of sterically, non-demanding alkenes. Additional steric hindrance in the vicinity of ruthenium related to the presence of iodides ensures enhanced catalyst stability. The benefits are most apparent under challenging conditions, such as very low reaction concentrations, protic solvents or with the occurrence of impurities.

  6. Determination of microamounts of potassium in sodium iodide by atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Microdetermination of potassium in sodium iodide was developed by the standard addition method. Twenty grams of sample were dissolved in 50 ml of water in a quartz beaker. To the solution, 30 ml of concentrated hydrochloric acid and 30 ml of 30% hydrogen peroxide were added, and evaporated to dryness. By this process sodium iodide was converted into sodium chloride. The cake thus obtained was dissolved in water and diluted to exactly 200 ml. To 25 ml aliquots of the solution, the standard potassium and cesium chloride solutions were added and diluted to 50 ml with water; the concentration of potassium was 0 -- 1 mg/l and that of cesium 4 mM. These solutions were introduced into an air-propane flame and the absorbances were measured at 769.9 nm. During the conversion reaction, hydrochloric acid was completely decomposed, and remained hydrogen peroxide had no influence for absorbance, and other backgrounds were negligible. The linear calibration curve was obtained in the range 0 -- 2 mg of potassium per liter. Potassium in sodium iodide was determined by this method within the coefficient of variation of +-(20 -- 3)% in the range (1.7 -- 32.5) ppm. (author)

  7. Iodide Sorption to Clays and the Relationship to Surface Charge and Clay Texture - 12356

    International Nuclear Information System (INIS)

    Iodine is assumed to behave conservatively in clay barriers around nuclear waste repositories and in natural sediments. Batch experiments tend to show little to no sorption, while in column experiments iodine is often retarded relative to tritiated water. Current surface complexation theory cannot account for negatively charged ion sorption to a negatively charged clay particle. Surface protonation and iodide sorption to clay minerals were examined using surface titrations and batch sorption experiments with a suite of clay minerals. Surface titrations were completed spanning a range of both pH values and ionic strengths. For reference, similar titrations were performed on pure forms of an Al-O powder. The titration curves were deconvoluted to attain the pKa distribution for each material at each ionic strength. The pKa distribution for the Al-O shows two distinct peaks at 4.8 and 7.5, which are invariant with ionic strength. The pKa distribution of clays was highly variable between the different minerals and as a function of ionic strength. Iodide sorption experiments were completed at high solid:solution ratios to exacerbate sorption properties. Palygorskite and kaolinite had the highest amount of iodide sorption and montmorillonite had the least. (authors)

  8. Study on multiphoton ionization dissociation processes of ethyl iodide at 800 nm laser radiation

    International Nuclear Information System (INIS)

    Multiphoton ionization-dissociation (MPID) process of ethyl iodide are studied at 800 nm femto-second laser, and time-of-flight mass spectrometer of ethyl iodide are obtained. The result of laser power index shows that the parent-ion mainly undergoes the 3 + 3 resonant enhanced multiphoton ionization (REMPI) process. The percentage of part fragment ions to the total ion current and the laser intensity dependence of the molecule are measured. Based on the experiment results, the multiphoton ionization- dissociation mechanism of ethyl iodide is discussed. The conclusion is that most of ion fragments are produced by C2H5I+ dissociation, this is consistent with the parent-ion dissociation staircase. The two possible dissociation channels of parent-ion are analyzed, but the C-I dissociation is the main channel. We also use Gaussian 03 calculated the energy change of the two channels with B3LYP/3-21G basis set, the theoretical results further demonstrated the experiment. (authors)

  9. Radiofrequency induction on sodium/iodide symporter expression of thyroid cancer

    Institute of Scientific and Technical Information of China (English)

    Youxin Tian; Qinjiang Liu; Yaqiong Ni

    2013-01-01

    Objective:The aim of this study was to investigate the ef ects of radiofrequency treatment on sodium/iodide symporter expression of thyroid cancer cells. Methods:In 29 thyroid cancer patients with low or no expression of soda\\iodide symporter, the radio frequency combined 131I therapy was used, the whole-body scintigraphy and serum Ig were detected before and after the radiofrequency treatment. Results:The whole-body scintigraphy showed that 4 cases (4/29) before radiofrequency treatment had positive iodine uptake, 19 cases (19/29) two weeks after radiofrequency treatment had the positive iodine uptake, 12 cases (12/29) four weeks after radiofrequency treatment had the positive iodine uptake. Four weeks after radiofrequency treatment, 5 cases had increased serum Ig levels, 17 cases had decreased serum Ig levels, 7 cases showed no change. 25 cases (25/29) were ef ective, 15 cases (15/29) were cured. Conclusion:The radiofrequency induced the non-expressed the sodium/iodide symporter of thyroid cancer cells regain the iodine intake ability, it improved the clinical ef icacy of 131I therapy in dedif erentiated thyroid cancer.

  10. Simple and rapid determination of iodide in table salt by stripping potentiometry at a carbon-paste electrode.

    Science.gov (United States)

    Svancara, Ivan; Ogorevc, Bozidar; Nović, Milko; Vytras, Karel

    2002-04-01

    A simple and rapid procedure, utilising constant-current stripping analysis (CCSA) at a carbon-paste electrode containing tricresyl phosphate as a pasting liquid (TCP-CPE), has been developed for the determination of iodide in table salt. Because of a synergistic accumulation mechanism based on ion-pairing and extraction of iodide in combination with electrolytic pretreatment of the TCP-CPE, the method is selective for iodide and enables direct determination of iodide in samples of table salt containing anti-caking agents such as K(4)[Fe(CN)(6)] (food additive "E 536") or MgO. The iodide content (calculated as KI) can be determined in a concentration range of 2 to 100 mg kg(-1) salt, with a detection limit (S/N=3) of 1 mg kg(-1), and a recovery from 90 to 115%. The proposed method has been used to determine iodide in several types of artificially iodised table salt and in one sample of natural sea salt. The results obtained agreed well with those obtained by use of three independent reference methods (titration, spectrophotometry, and ICP-MS) used to validate the CCSA method, indicating that the developed method is applicable as a routine procedure for rapid testing in salt production process control and in the analysis of marketed table salts.

  11. Assessment of PCDD/F and PBDD/F Emissions from Coal-fired Power Plants during Injection of Brominated Activated Carbon for Mercury Control

    Science.gov (United States)

    The effect of the injection of brominated powdered activated carbon (Br-PAC) on the emission of brominated and chlorinated dioxins and furans in coal combustion flue gas has been evaluated. The tests were performed at two U.S. Department of Energy (DOE) demonstration sites where ...

  12. Hyphenation of ultra performance liquid chromatography (UPLC) with inductively coupled plasma mass spectrometry (ICP-MS) for fast analysis of bromine containing preservatives

    DEFF Research Database (Denmark)

    Bendahl, Lars; Hansen, Steen Honoré; Gammelgaard, Bente;

    2006-01-01

    Ultra performance liquid chromatography (UPLC) was coupled to inductively coupled plasma mass spectrometry (ICP-MS) for fast analysis of three bromine-containing preservatives, monitoring the 79Br and 81Br isotopes simultaneously. Due to the efficiency of the 1.7 microm column packing material...... analysis of bromine-containing preservatives in commercially available cosmetic products....

  13. Molecular simulations and density functional theory calculations of bromine in clathrate hydrate phases

    International Nuclear Information System (INIS)

    Bromine forms a tetragonal clathrate hydrate structure (TS-I) very rarely observed in clathrate hydrates of other guest substances. The detailed structure, energetics, and dynamics of Br2 and Cl2 in TS-I and cubic structure I (CS-I) clathrate hydrates are studied in this work using molecular dynamics and quantum chemical calculations. X-ray diffraction studies show that the halogen-water–oxygen distances in the cages of these structures are shorter than the sum of the van der Waals radii of halogen and oxygen atoms. This suggests that the stabilizing effects of halogen bonding or other non-covalent interactions (NCIs) may contribute to the formation of the unique tetragonal bromine hydrate structure. We performed molecular dynamics simulations of Br2 and Cl2 clathrate hydrates using our previously developed five-site charge models for the dihalogen molecules [Dureckova et al. Can. J. Chem. 93, 864 (2015)] which reproduce the computed electrostatic potentials of the dihalogens and account for the electropositive σ-hole of the halogen bond donor (the dihalogen). Analysis of the radial distribution functions, enthalpies of encapsulation, velocity and orientation autocorrelation functions, and polar angle distributions are carried out for Br2 and Cl2 guests in various cages to contrast the properties of these guests in the TS-I and CS-I phases. Quantum chemical partial geometry optimizations of Br2 and Cl2 guests in the hydrate cages using the M06-2X functional give short halogen-water distances compatible with values observed in X-ray diffraction experiments. NCI plots of guest-cage structures are generated to qualitatively show the relative strength of the non-bonding interactions between dihalogens and water molecules. The differences between behaviors of Br2 and Cl2 guests in the hydrate cages may explain why bromine forms the unique TS-I phase

  14. Production of HBR from bromine and steam for off-peak electrolytic hydrogen generation

    Energy Technology Data Exchange (ETDEWEB)

    Schlief, R.E.; Hanrahan, R.J.; Stoy, M.A. [Univ. of Florida, Gainesville, FL (United States)] [and others

    1995-09-01

    Progress is reported on the development of a renewable energy source based solar-electrolytic system for production of hydrogen and oxygen. It employs water, bromine, solar energy and supplemental electrical power. The concept is being developed by Solar Reactor Technologies, Inc., (SRT), with the U.S. Department of Energy (DOE). An overview of the nature and objectives of this program is provided here, and technical progress made during the first (three-month) performance period of the Phase I work effort is reported. The SRT concept entails (1) absorption of concentrated solar radiation by bromine vapor Br{sub 2(g)} in a high-temperature reactor producing Br{sub (g)} atoms, (2) reaction of Br{sub (g)} with water yielding hydrogen bromide (HBr), and (3) electrolysis of stored hydrogen bromide for production of H{sub 2(g)} and recovery of Br{sub 2(I)}. Incorporation of solar radiation in the primary photochemical step (1) reduces by 50 - 70% the electrical power required to split water. The SRT concept is very attractive from an economic viewpoint as well. The reversible fuel cell, employed in the SRT electrolysis concept is capitalized via its use in load leveling by the utility. A 1 kW solar reactor was designed and constructed during the first three-month performance period by SRT personnel at the University of Florida, Gainesville. It was employed in taking survey data of the reaction between bromine and steam at temperatures between 900 and 1300 K. This reaction was run under purely thermal conditions, i.e. in the absence of solar photons. The experimental data are reported and interpreted employing concomitant thermodynamic calculations. The anticipated improvement is discussed briefly as well as the effect of a photochemical boost to the reaction. The amount of this enhancement will be studied in the next three month performance period.

  15. Effect of brominated furanones on the formation of biofilm by Escherichia coli on polyvinyl chloride materials.

    Science.gov (United States)

    Lianhua, Ye; Yunchao, Huang; Geng, Xu; Youquang, Zhou; Guangqiang, Zhao; Yujie, Lei

    2013-01-01

    To study the influence of brominated furanones on the biofilm (BF) formation by Escherichia coli (E. coli) on polyvinyl chloride (PVC) material, and to provide new ways of surface modification of materials to clinically prevent biomaterial centered infection. Three brominated furanones, dissolved in ethanol, furanone-1(3,4-dibromo-5-hydroxyl-furanone), furanone-2(4-bromo-5-(4-methoxypheny)-3-(methylamino)-furanone), and furanone-3(3,4-dibromo-5,5-dimethoxypheny-2(5H)-furanone) with representative chemical structure, were coated on the surfaces of separate PVC materials (1 × 1 cm), respectively. The surface-modified PVC materials were incubated with E. coli and for controls, 75 % ethanol-treated PVC materials were used. This treatment played as control group. The cultivation incubations were for 6, 12, 18, and 24 h. The thickness of bacterial BF and bacterial community quantity unit area on the PVC materials was determined by confocal laser scanning microscopy (CLSM), and the surface structure of bacterial BF formation was examined by scanning electron microscopy (SEM). The results of CLSM indicated the thickness of bacterial BF and bacterial community quantity unit area on PVC materials treated with furanone-3 were significantly lower than that of control at all time points (P 0.05). The results of SEM indicated that after 6 h incubation, the quantity of bacterial attachment to the surface of PVC material treated with furanone-3 was lower than the control group. By 18 h incubation there was completely formed BF structure on the surface of control PVC material. However, there was no significant BF formation on the surface of PVC material treated with furanone-3. The impact of different brominated furanones on SA biofilm formation on the surface of PVC materials are different, furanone-3 can inhibit E. coli biofilm formation on the surface of PVC material.

  16. Ways of reducing the bromine numbers of benzene for nitration with the use of the piperylene additive

    Energy Technology Data Exchange (ETDEWEB)

    Kolyandr, L.Ya.; Litvinenko, A.M.; Mastyukov, V.A.; Potapchenko, A.A.; Savikkova, M.T.; Shoherbakova, T.G.; Shuzhenko, E.A.; Titarenko, V.G.; Tkachenko, L.A.

    1981-01-01

    To study the diminution of the bromine numbers of benzene for nitration, an investigation has been made of the impurities according to the fractions of the tests of benzene production of three coke and chemical works: the works in Makeev-a, ka, Bagleisk and Yenakievo. It has been found that when the piperylene additive is used, the value of the bromine numbers of benzene for nitration is determined, in the main, not by the piperylenes removed during purification. When the intermediate BT fractions are not sufficiently clearly selected, the value of the bromine numbers of benzene is influenced also by the impurities which are concentrated in its terminal fractions. To radically remove piperylenes, it is necessary to improve the contact between the acid and the fraction being purified; this is attained by intensifying mixing and lengthening the purification process.

  17. Reaction modelling of Iron Oxide Bromination in the UT-3 thermochemical cycle for Hydrogen production from water

    International Nuclear Information System (INIS)

    Analysis modelling of the iron oxide bromination had been carried out using experiment data from the iron oxide bromination in the UT-3 thermochemical cycle. Iron oxide in the form of pellets were made of the calcination of the mixture of iron oxide, silica, graphite and cellulose at 1473 K. Thermobalance reactor was used to study the kinetic reactions of the iron oxide bromination at a temperature of 473 K for 2 - 6 hours. The data collected from the experiments were used as input for the common models. However, none of these models could not explain the result of the experiments. A new model, a combination of two kinetic reactions : exposed particle and coated particle was created and worked successfully

  18. SYNTHESIS AND GREEN BROMINATION OF SOME CHALCONES AND THEIR ANTIMICROBIAL SCREENING

    Directory of Open Access Journals (Sweden)

    Mayur R. Adokar

    2013-04-01

    Full Text Available Chalcones are the versatile molecules having the structural flexibility which permits structural transformations into flavonoids, flavanones, pyrazoles, oxazoles, pyrimidines etc. Changes in their structure have offered the development of new medicinal agents having improved pharmacological potency. Their derivatives have attracts increasing attention due to numerous pharmacological potential. In the present communication we report the synthesis of chalcones from various acetophenone derivatives with different aromatic aldehydes and green chemistry approach to their bromination with the help of Tetrabutylammonium Tribromide (TBATB. All the synthesized chalcone dibromides were screened for their antimicrobial activity against Aspergillus flavus, Rhizopus sp., Fusarium solani and Aspergillus niger.

  19. Brominated flame retardants in waste electrical and electronic equipment: substance flows in a recycling plant.

    Science.gov (United States)

    Morf, Leo S; Tremp, Josef; Gloor, Rolf; Huber, Yvonne; Stengele, Markus; Zennegg, Markus

    2005-11-15

    Brominated flame retardants (BFRs) are synthetic additives mainly used in electrical and electronic appliances and in construction materials. The properties of some BFRs are typical for persistent organic pollutants, and certain BFRs, in particular some polybrominated diphenyl ether (PBDE) congeners and hexabromocyclododecane (HBCD), are suspected to cause adverse health effects. Global consumption of the most demanded BFRs, i.e., penta-, octa-, and decaBDE, tetrabromobisphenol A (TBBPA), and HBCD, has doubled in the 1990s. Only limited and rather uncertain data are available regarding the occurrence of BFRs in consumer goods and waste fractions as well as regarding emissions during use and disposal. The knowledge of anthropogenic substance flows and stocks is essential for early recognition of environmental impacts and effective chemicals management. In this paper, actual levels of penta-, octa-, and decaBDE, TBBPA, and HBCD in waste electrical and electronic equipment (WEEE) as a major carrier of BFRs are presented. These BFRs have been determined in products of a modern Swiss recycling plant applying gas chromatography/electron capture detection and gas chromatography/mass spectrometry analysis. A substance flow analysis (SFA) technique has been used to characterize the flows of target substances in the recycling process from the bulk WEEE input into the output products. Average concentrations in small size WEEE, representing the relevant electric and electronic appliances in WEEE, sampled in 2003 amounted to 34 mg/kg for pentaBDE, 530 mg/kg for octaBDE, 510 mg/kg for decaBDE, 1420 mg/kg for TBBPA (as an additive), 17 mg/kg for HBCD, 5500 mg/kg for bromine, and 1700 mg/kg for antimony. In comparison to data that have been calculated by SFA for Switzerland from literature for the 1990s, these measured concentrations in small size WEEE were 7 times higher for pentaBDE, unexpectedly about 50% lower for decaBDE, and agreed fairly well for TBBPA (as an additive) and

  20. Antibacterial Activities of a New Brominated Diterpene from Borneon Laurencia spp

    Science.gov (United States)

    Vairappan, Charles Santhanaraju; Ishii, Takahiro; Lee, Tan Kai; Suzuki, Minoru; Zhaoqi, Zhan

    2010-01-01

    In our continuous interest to study the diversity of halogenated metabolites of Malaysian species of the red algal genus Laurencia, we examined the chemical composition of five populations of unrecorded Laurencia sp. A new brominated diterpene, 10-acetoxyangasiol (1), and four other known metabolites, aplysidiol (2), cupalaurenol (3), 1-methyl-2,3,5-tribromoindole (4), and chamigrane epoxide (5), were isolated and identified. Isolated metabolites exhibited potent antibacterial activities against clinical bacteria, Staphylococcus aureus, Staphylococcus sp., Streptococcus pyogenes, Salmonella sp. and Vibrio cholerae. PMID:20631866

  1. Antibacterial Activities of a New Brominated Diterpene from Borneon Laurencia spp.

    Directory of Open Access Journals (Sweden)

    Charles Santhanaraju Vairappan

    2010-05-01

    Full Text Available In our continuous interest to study the diversity of halogenated metabolites of Malaysian species of the red algal genus Laurencia, we examined the chemical composition of five populations of unrecorded Laurencia sp. A new brominated diterpene, 10-acetoxyangasiol (1, and four other known metabolites, aplysidiol (2, cupalaurenol (3, 1-methyl-2,3,5-tribromoindole (4, and chamigrane epoxide (5, were isolated and identified. Isolated metabolites exhibited potent antibacterial activities against clinical bacteria, Staphylococcus aureus, Staphylococcus sp., Streptococcus pyogenes, Salmonella sp. and Vibrio cholerae.

  2. The use of mercuric iodide in instruments for safeguards and non-proliferation applications

    International Nuclear Information System (INIS)

    Mercuric Iodide is a material exceptionally suited for solid state detectors operating at room temperature. The high density and the high atomic numbers of the constituent elements provide a large absorption factor and a high full-energy-peak efficiency at gamma ray energies. The large electronic bandgap results in a very high resistivity and therefore a low leakage current at temperatures within and outside the personal comfort range. Constellation Technology has developed the technology to grow large, high quality crystals from mercuric iodide. Spectrometry grade detectors with dimensions of 25 mm x 25 mm x 3 mm and with an energy resolution of approximately 3% FWHM at 662 keV can be fabricated from these mercuric iodide crystals. The resolution of this detector approximately 1.8% FWHM and the peak-to-valley ratio is larger than twelve. Standard semi-Gaussian processing and no pulse-shape discrimination was used. These detectors can be conveniently incorporated into hand-held instruments to detect weak sources or heavily shielded sources. Previous measurements have shown that the Minimum Detectable Activity (MDA) of a 3 mm thick mercuric iodide detector with dimensions as given above is about 10% less than the MDA of a 50 mm x 50 mm sodium iodide detector, due to the superior energy resolution. Software methods are being developed to improve the identification of weak sources against a large background. Results of these measurements will be presented. Smaller detectors can be used in safeguards applications where the intensity of the radiation is relatively high. The spectral resolution of the detectors is high enough to clearly identify the significant energy lines in the spectra of stored uranium and plutonium. The shape of the spectral peaks is constant over a large range of energies so that existing software systems can be used to analyze the spectra. The small size, ruggedness, temperature stability and high efficiency of these detectors makes them good

  3. Reduction of stimulated sodium iodide symporter expression by estrogen receptor ligands in breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Cheong, Su-Jin; Jang, DooRye; Jeong, Hwan-Jeong; Lim, Seok Tae; Sohn, Myung-Hee [Department of Nuclear Medicine, Cyclotron Research Center, Research Institute of Clinical Medicine, Chonbuk National University Medical School, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Katzenellenbogen, John A., E-mail: jkatzene@illinois.ed [Department of Chemistry, University of Illinois, Urbana, IL 61801 (United States); Kim, Dong Wook, E-mail: kimdw@chonbuk.ac.k [Department of Nuclear Medicine, Cyclotron Research Center, Research Institute of Clinical Medicine, Chonbuk National University Medical School, Jeonju, Jeonbuk 561-756 (Korea, Republic of)

    2011-02-15

    Purpose: The sodium iodide symporter (NIS) mediates active iodide uptake in lactating breast tissue, and when its levels are enhanced by all-trans retinoic acid (atRA), NIS has been proposed as a target for the imaging and radiotherapy of breast cancer. Importantly, the estrogen receptor {alpha} (ER{alpha}) is an important regulator of atRA induced NIS gene expression in breast cancer cells. In this study, we investigated the effect of an ER agonist (17{beta}-estradiol, E{sub 2}) or antagonist [trans-hydroxytamoxifen (TOT) or raloxifene (RAL)] treatment on the regulation of NIS gene expression and iodide uptake in an ER{alpha}-positive breast cancer (MCF-7) model. Methods: NIS functional activity was measured in vitro by {sup 125}I uptake assay after incubation with E{sub 2} (from 10{sup -15} to 10{sup -5} M), TOT (from 5x10{sup -8} to 5x10{sup -6} M), or RAL (from 5x10{sup -8} to 5x10{sup -6} M) in the presence or absence of atRA (10{sup -7} M). Under the same conditions, NIS mRNA expression was examined by reverse transcriptase polymerase chain reaction. Athymic mice with MCF-7 xenograft tumors were treated with atRA alone or atRA together with E{sub 2} to evaluate the change of {sup 125}I uptake in tumor tissues in vivo. Results: In the iodide uptake study in cells, E{sub 2}, TOT, or RAL treatment alone did not stimulate {sup 125}I uptake. However, when iodide uptake was stimulated by atRA, cotreatment with E{sub 2}, TOT or RAL decreased {sup 125}I uptake in a concentration-dependent manner. The hormone effects on NIS mRNA expression levels in MCF-7 cells were similar. The results of the in vivo biodistribution study showed that {sup 125}I uptake was reduced 50% in tumor tissues of mice treated with atRA/E{sub 2} as compared to tumors treated only with atRA. Conclusion: Our results suggest that combination treatment of atRA and ER ligands could limit the functional activity of the NIS gene induced by atRA, thereby compromising its use as a target for diagnosis

  4. Price Wars and the Stability of Collusion: A Study of the Pre-World War I Bromine Industry

    OpenAIRE

    Margaret Levenstein

    1993-01-01

    Bromine producers colluded to raise prices and profits during most of the period between 1885 and 1914. Collusion was punctuated by price wars in which prices fell sharply. The characteristics of these price wars are compared with those in the Green-Porter and Abreu- Pearce-Stachetti models. Some of the bromine price wars resulted from the imperfect monitoring problems in these models. Those price wars were short and mild. More severe price wars were part of a bargaining process, in which fir...

  5. Synchrotron X-ray fluorescence studies of a bromine-labelled cyclic RGD peptide interacting with individual tumor cells

    International Nuclear Information System (INIS)

    The first example of synchrotron X-ray fluorescence imaging of cultured mammalian cells in cyclic peptide research is reported. The study reports the first quantitative analysis of the incorporation of a bromine-labelled cyclic RGD peptide and its effects on the biodistribution of endogenous elements (for example, K and Cl) within individual tumor cells. The first example of synchrotron X-ray fluorescence imaging of cultured mammalian cells in cyclic peptide research is reported. The study reports the first quantitative analysis of the incorporation of a bromine-labelled cyclic RGD peptide and its effects on the biodistribution of endogenous elements (for example, K and Cl) within individual tumor cells

  6. Distribution and speciation of bromine in mammalian tissue and fluids by X-ray fluorescence imaging and X-ray absorption spectroscopy.

    Science.gov (United States)

    Ceko, Melanie J; Hummitzsch, Katja; Hatzirodos, Nicholas; Bonner, Wendy; James, Simon A; Kirby, Jason K; Rodgers, Raymond J; Harris, Hugh H

    2015-05-01

    Bromine is one of the most abundant and ubiquitous trace elements in the biosphere and until recently had not been shown to perform any essential biological function in animals. A recent study demonstrated that bromine is required as a cofactor for peroxidasin-catalysed formation of sulfilimine crosslinks in Drosophila. In addition, bromine dietary deficiency is lethal in Drosophila, whereas bromine replenishment restores viability. The aim of this study was to examine the distribution and speciation of bromine in mammalian tissues and fluids to provide further insights into the role and function of this element in biological systems. In this study we used X-ray fluorescence (XRF) imaging and inductively coupled plasma-mass spectrometry (ICP-MS) to examine the distribution of bromine in bovine ovarian tissue samples, follicular fluid and aortic serum, as well as human whole blood and serum and X-ray absorption spectroscopy (XAS) to identify the chemical species of bromine in a range of mammalian tissue (bovine, ovine, porcine and murine), whole blood and serum samples (bovine, ovine, porcine, murine and human), and marine samples (salmon (Salmo salar), kingfish (Seriola lalandi) and Scleractinian coral). Bromine was found to be widely distributed across all tissues and fluids examined. In the bovine ovary in particular it was more concentrated in the sub-endothelial regions of arterioles. Statistical comparison of the near-edge region of the X-ray absorption spectra with a library of bromine standards led to the conclusion that the major form of bromine in all samples analysed was bromide. PMID:25675086

  7. Analytical approaches for determination of bromine in sediment core samples by X-ray fluorescence spectrometry.

    Science.gov (United States)

    Pashkova, Galina V; Aisueva, Tatyana S; Finkelshtein, Alexander L; Ivanov, Egor V; Shchetnikov, Alexander A

    2016-11-01

    Bromine has been recognized as a valuable indicator for paleoclimatic studies. Wavelength dispersive X-ray fluorescence (WDXRF) and total reflection X-ray fluorescence (TXRF) methods were applied to study the bromine distributions in lake sediment cores. Conventional WDXRF technique usually requires relatively large mass of a sediment sample and a set of calibration samples. Some analytical approaches were developed to apply WDXRF to small sediment core samples in the absence of adequate calibration samples with a known Br content. The mass of a sample to be analyzed was reduced up to 200-300mg and the internal standard method with correction using fundamental parameters was developed for Br quantification. TXRF technique based on the direct analysis of a solid suspension using 20mg of sediment sample by internal standard method was additionally tested. The accuracy of the WDXRF and TXRF techniques was assessed by the comparative analysis of reference materials of sediments, soil and biological samples. In general, good agreement was achieved between the reference values and the measured values. The detection limits of Br were 1mg/kg and 0.4mg/kg for WDXRF and TXRF respectively. The results of the Br determination obtained with different XRF techniques were comparable to each other and used for paleoclimatic reconstructions. PMID:27591627

  8. Synthesis of α-Bromine- Terminated Polystyrene Macroinitiator and Its Initiation of MMA Polymerization by ATRP

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In the present paper the synthesis of block copolymers via the transformation from living anionic polymerization (LAP) to atom transfer radical polymerization (ATRP) was described. Α-Bromine-terminated polystyrenes(PStBr) in the LAP step was prepared by using n-BuLi as initiator, tetrahydrofuran (THF) as the activator, α-methylstyrene (α-MeSt) as the capping group and liquid bromine (Br2) as the bromating agent. The effects of reaction conditions such as the amounts of α-MeSt, THF, and Br2 as well as molecular weight of polystyrene on the bromating efficiency (BE) and coupling extent (CE) were examined. The present results show that the yield of PStBr obtained was more than 93.8% and the coupling reaction was substantially absent. PStBr was further used as the macroinitiator in the polymerization of methyl-methacrylate(MMA) in the presence of copper(Ⅰ) halogen and 2,2-bipyridine(bpy) complexes. It was found that the molecular weight of the resulted PSt-b-PMMA increased linearly with the increase of the conversion of MMA and the polydispersity was 1.2-1.6. The structures of PStBr and P(St-b-MMA) were characterized by 1H NMR spectra.

  9. Levelized cost of energy and sensitivity analysis for the hydrogen-bromine flow battery

    Science.gov (United States)

    Singh, Nirala; McFarland, Eric W.

    2015-08-01

    The technoeconomics of the hydrogen-bromine flow battery are investigated. Using existing performance data the operating conditions were optimized to minimize the levelized cost of electricity using individual component costs for the flow battery stack and other system units. Several different configurations were evaluated including use of a bromine complexing agent to reduce membrane requirements. Sensitivity analysis of cost is used to identify the system elements most strongly influencing the economics. The stack lifetime and round-trip efficiency of the cell are identified as major factors on the levelized cost of electricity, along with capital components related to hydrogen storage, the bipolar plate, and the membrane. Assuming that an electrocatalyst and membrane with a lifetime of 2000 cycles can be identified, the lowest cost market entry system capital is 220 kWh-1 for a 4 h discharge system and for a charging energy cost of 0.04 kWh-1 the levelized cost of the electricity delivered is 0.40 kWh-1. With systems manufactured at large scales these costs are expected to be lower.

  10. Hair as an indicator of endogenous tissue levels of brominated flame retardants in mammals.

    Science.gov (United States)

    D'Havé, Helga; Covaci, Adrian; Scheirs, Jan; Schepens, Paul; Verhagen, Ron; De Coen, Wim

    2005-08-15

    Few data are available on brominated flame retardants (BFRs) in terrestrial mammalian wildlife. Moreover, the use of hair in nondestructive monitoring of BFRs in mammals or humans has not been investigated. In the present study, concentrations of polybrominated diphenyl ethers (PBDEs) and brominated biphenyl 153 (BB 153) were analyzed in tissues of the European hedgehog Erinaceus europaeus. Road kills and carcasses from wildlife rescue centers were used to investigate relationships between concentrations of BFRs in hair and internal tissues, BFR tissue distribution (hair, liver, kidney, muscle, and adipose tissue), and PBDE congener tissue pattern dissimilarities. Liver concentrations of PBDEs and BB 153 were in the ranges 1-1178 and 0-2.5 ng/g of liver wet weight, respectively. PBDEs were predominant in adipose tissue and liver, while accumulation of BB 153 was tissue independent. The less persistent compound BDE 99 was more dominant in hair than in internal tissues. We observed positive relationships between BFR levels in hair and internal tissues for sum PBDEs and BDE 47 (0.37 terrestrial mammals which can be used in nondestructive monitoring schemes.

  11. Dissolution of brominated epoxy resins by dimethyl sulfoxide to separate waste printed circuit boards.

    Science.gov (United States)

    Zhu, Ping; Chen, Yan; Wang, Liangyou; Qian, Guangren; Zhang, Wei Jie; Zhou, Ming; Zhou, Jin

    2013-03-19

    Improved methods are required for the recycling of waste printed circuit boards (WPCBs). In this study, WPCBs (1-1.5 cm(2)) were separated into their components using dimethyl sulfoxide (DMSO) at 60 °C for 45 min and a metallographic microscope was used to verify their delamination. An increased incubation time of 210 min yielded a complete separation of WPCBs into their components, and copper foils and glass fibers were obtained. The separation time decreased with increasing temperature. When the WPCB size was increased to 2-3 cm(2), the temperature required for complete separation increased to 90 °C. When the temperature was increased to 135 °C, liquid photo solder resists could be removed from the copper foil surfaces. The DMSO was regenerated by rotary decompression evaporation, and residues were obtained. Fourier transform infrared spectroscopy (FT-IR), thermal analysis, nuclear magnetic resonance, scanning electron microscopy, and energy-dispersive X-ray spectroscopy were used to verify that these residues were brominated epoxy resins. From FT-IR analysis after the dissolution of brominated epoxy resins in DMSO it was deduced that hydrogen bonding may play an important role in the dissolution mechanism. This novel technology offers a method for separating valuable materials and preventing environmental pollution from WPCBs. PMID:23398278

  12. Biodegradation kinetics of selected brominated flame retardants in aerobic and anaerobic soil

    Energy Technology Data Exchange (ETDEWEB)

    Nyholm, Jenny Rattfelt, E-mail: jenny.rattfelt@chem.umu.s [Department of Chemistry, Umea University, SE-901 87 Umea (Sweden); Lundberg, Charlott; Andersson, Patrik L. [Department of Chemistry, Umea University, SE-901 87 Umea (Sweden)

    2010-06-15

    The purpose of the present study was to investigate the biodegradation kinetics in aerobic and anaerobic soil of the following brominated flame retardants: 2,4,4'-tribromodiphenyl ether (BDE 28), decabromodiphenyl ether (BDE 209), tetrabromobisphenol A (TBBPA), 1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane (TBECH), 2,4,6-tribromophenol (246BrPh), and hexabromobenzene (HxBrBz). For comparison, the biodegradation of the chlorinated compounds 2,4,4'-trichlorodiphenyl ether (CDE 28), 2,4,6-trichlorophenol (246ClPh), hexachlorobenzene (HxClBz), and 2,2',4,4',5,5'-hexachlorobiphenyl (PCB 153) was also assessed. In aerobic soil, BDE 209 showed no significant degradation during the test period, but concentrations of the other BFRs declined, with half-lives decreasing in the following order: BDE 28 > TBBPA > TBECH > HxBrBz > 246BrPh. Declines in almost the same order were observed in anaerobic soil: BDE 28, BDE 209 > TBBPA > HxBrBz > TBECH >246BrPh. - Intra- and extrapolated half-lives in soil of tested brominated flame retardants ranged from 7 days for 2,4,6-tribromorophenol to >400 days for decabromodiphenyl ether.

  13. Novel Spectrophotometric Method for Determination of Macro-paracetamol via Reaction with Bromine

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    The reaction between Br2 and paracetamol(p-AAP) leads to the formation of a coloured product, which can be used for spectrophotometric determination of the p-AAP content in its pure form and in different pharmaceutical preparations with p-AAP. The stoichiometric composition of the reaction was found to be n(p-AAP)∶n(bromine)=1∶3. The effects of pH and time on the spectra of p-AAP-bromine redox reaction product were studied. The interference of different additives on the measured spectra of the obtained product was also studied. The results obtained by the present method were compared with those obtained by the standard method. The F- and t- test values were calculated for both of the applied procedures and they met a confidence level of 99%. The proposed procedure actually needs no separation of these drugs from their sources before analysis and was unaffected by interference of other phenolic compounds. The proposed method is simpler and faster than the repoeted ones.

  14. Selected chlorobornanes, polychlorinated naphthalenes and brominated flame retardants in Bjornoya (Bear Island) freshwater biota

    International Nuclear Information System (INIS)

    Levels of selected sparsely investigated persistent organic pollutants (POPs) have been measured in organisms from two Arctic lakes on Bjornoya (Bear Island). Elevated levels of chlorobornanes (CHBs) (up to 46.7 ng/g wet weight=ww), polybrominated diphenyl ethers (PBDEs) (up to 27.2 ng/g ww), polybrominated biphenyls (PBBs) (up to 1.1 ng/g ww) and polychlorinated naphthalenes (PCNs, only 4 congeners) (up to 62.7 pg/g ww), were measured in biota from Lake Ellasjoen. In Lake Oyangen, located only 5 km north of Ellasjoen, levels of these contaminants were significantly lower. δ15N-values were 7-10%o higher in organisms from Ellasjoen as compared to Oyangen. This is attributed to biological inputs related to seabird activities. The present study illustrates that contaminants such as CHBs, brominated flame retardants and PCNs accumulate in the Ellasjoen food web in a manner similar to PCBs and conventional organochlorine pesticides. Transport mechanisms that control PCB and DDT distributions, i.e. atmospheric long-range transport and biotransport by seabirds, are also relevant for the contaminants investigated in the present study. - Elevate levels of chlorobornanes, polychlorinated naphthalenes and brominated flame retardants have been measured in biota from a Norwegian Arctic lake

  15. Development of Zinc/Bromine Batteries for Load-Leveling Applications: Phase 2 Final Report

    Energy Technology Data Exchange (ETDEWEB)

    CLARK,NANCY H.; EIDLER,PHILLIP

    1999-10-01

    This report documents Phase 2 of a project to design, develop, and test a zinc/bromine battery technology for use in utility energy storage applications. The project was co-funded by the U.S. Department of Energy Office of Power Technologies through Sandia National Laboratories. The viability of the zinc/bromine technology was demonstrated in Phase 1. In Phase 2, the technology developed during Phase 1 was scaled up to a size appropriate for the application. Batteries were increased in size from 8-cell, 1170-cm{sup 2} cell stacks (Phase 1) to 8- and then 60-cell, 2500-cm{sup 2} cell stacks in this phase. The 2500-cm{sup 2} series battery stacks were developed as the building block for large utility battery systems. Core technology research on electrolyte and separator materials and on manufacturing techniques, which began in Phase 1, continued to be investigated during Phase 2. Finally, the end product of this project was a 100-kWh prototype battery system to be installed and tested at an electric utility.

  16. Tropospheric Bromine Chemistry: Implications for Present and Pre-industrial Ozone and Mercury

    Science.gov (United States)

    Parella, J. P.; Jacob, D. J.; Liang, Q.; Zhang, Y.; Mickley, L. J.; Miller, B.; Evans, M. J.; Yang, X.; Pyle, J. A.; Theys, N.; VanRoozendael, M.

    2012-01-01

    We present a new model for the global tropospheric chemistry of inorganic bromine (Bry) coupled to oxidant-aerosol chemistry in the GEOS-Chem chemical transport model (CTM). Sources of tropospheric Bry include debromination of sea-salt aerosol, photolysis and oxidation of short-lived bromocarbons, and transport from the stratosphere. Comparison to a GOME-2 satellite climatology of tropospheric BrO columns shows that the model can reproduce the observed increase of BrO with latitude, the northern mid-latitudes maximum in winter, and the Arctic maximum in spring. This successful simulation is contingent on the HOBr + HBr reaction taking place in aqueous aerosols and ice clouds. Bromine chemistry in the model decreases tropospheric ozone mixing ratios by mercury against oxidation by Br. This suggests that historical anthropogenic mercury emissions may have mostly deposited to northern mid-latitudes, enriching the corresponding surface reservoirs. The persistent rise in background surface ozone at northern mid-latitudes during the past decades could possibly contribute to the observations of elevated mercury in subsurface waters of the North Atlantic.

  17. Brominated diphenyl ethers in the sediments, porewater, and biota of the Chesapeake Bay, USA

    Energy Technology Data Exchange (ETDEWEB)

    Baker, K.; Klosterhaus, S.; Liebert, D.; Stapleton, H. [Maryland Univ., Solomons, MD (United States)

    2004-09-15

    Levels of brominated diphenyl ethers (BDEs) are rapidly increasing in the environment, and in a short time these chemicals have evolved from 'emerging contaminants' to globally-distributed organic pollutants. Recent research demonstrates BDEs are sufficiently stable to be transported long distances in the environment and to accumulate in higher trophic levels. Photolysis and metabolism appear to be dominant loss processes for the parent compounds, generating a variety of lower brominated diphenyl ethers, hydroxylated metabolites, and other products. BDEs are hydrophobic, and therefore their transport in aquatic systems is likely controlled by sorption to sediments and perhaps exchange across the air-water interface. To date, few studies have examined the geochemistry of BDEs in natural waters. In this paper, we review our recent measurements of BDEs in the Chesapeake Bay, a shallow, productive estuary in eastern North America. We focus on the distribution of BDE congeners sediment, porewater, and in faunal benthos along a contamination gradient downstream from a wastewater treatment plant and on the spatial distribution of BDEs in bottom-feeding and pelagic fish species.

  18. Ultrafast optical limiting properties and transient dynamics of symmetrical phenoxazinium bromine salt

    Science.gov (United States)

    Xiao, Zhengguo; Ge, Jianfeng; Li, Zhongguo; Wu, Xingzhi; Fang, Yu; Shi, Guang; Zhang, Xueru; Wang, Yuxiao; Song, Yinglin

    2015-12-01

    A symmetrical phenoxazinium bromine salt with resonant D-π-D structure was prepared and spectroscopically characterized. The ultrafast nonlinear optical (NLO) response of the compound dissolved in DMF was investigated using open aperture Z-scan method with 190 fs laser pulses at 515 nm. And the photo-physical dynamics of the compound was studied using transient absorption spectra at femtosecond time regime. The titled sample showed strong reverse saturable absorption (RSA) at 515 nm. Transient absorption results demonstrated that the compound exhibited RSA signals at 478-580 nm and SA signals at 600-780 nm. A simplified three-energy-level model was used to determine the photo-physical parameters. And the excited-state lifetime was evaluated to be around one nanosecond. Our results show that the phenoxazinium bromine salt has a large ratio of singlet excited-state absorption cross-section to that of ground state cross-section (18.7), indicating it is a candidate material for future ultrafast optical limiters.

  19. Natural solar photolysis of total organic chlorine, bromine and iodine in water.

    Science.gov (United States)

    Abusallout, Ibrahim; Hua, Guanghui

    2016-04-01

    Municipal wastewater has been increasingly used to augment drinking water supplies due to the growing water scarcity. Wastewater-derived disinfection byproducts (DBPs) may negatively affect the aquatic ecosystems and human health of downstream communities during water reuse. The objective of this research was to determine the degradation kinetics of total organic chlorine (TOCl), bromine (TOBr) and iodine (TOI) in water by natural sunlight irradiation. Outdoor solar photolysis experiments were performed to investigate photolytic degradation of the total organic halogen (TOX) formed by fulvic acid and real water and wastewater samples. The results showed that TOX degradation by sunlight irradiation followed the first-order kinetics with half-lives in the range of 2.6-10.7 h for different TOX compounds produced by fulvic acid. The TOX degradation rates were generally in the order of TOI > TOBr ≅ TOCl(NH2Cl) > TOCl(Cl2). High molecular weight TOX was more susceptible to solar photolysis than corresponding low molecular weight halogenated compounds. The nitrate and sulfite induced indirect TOX photolysis rates were less than 50% of the direct photolysis rates under the conditions of this study. Fulvic acid and turbidity in water reduced TOX photodegradation. These results contribute to a better understanding of the fate of chlorinated, brominated and iodinated DBPs in surface waters.

  20. Selected chlorobornanes, polychlorinated naphthalenes and brominated flame retardants in Bjornoya (Bear Island) freshwater biota

    Energy Technology Data Exchange (ETDEWEB)

    Evenset, Anita [Akvaplan-niva, Polar Environmental Centre, N-9296 Tromso (Norway)]. E-mail: ae@akvaplan.niva.no; Christensen, Guttorm N. [Akvaplan-niva, Polar Environmental Centre, N-9296 Tromso (Norway); Kallenborn, Roland [Norwegian Institute for Air Research, P.O. Box 100, N-2027 Kjeller (Norway)

    2005-08-15

    Levels of selected sparsely investigated persistent organic pollutants (POPs) have been measured in organisms from two Arctic lakes on Bjornoya (Bear Island). Elevated levels of chlorobornanes (CHBs) (up to 46.7 ng/g wet weight=ww), polybrominated diphenyl ethers (PBDEs) (up to 27.2 ng/g ww), polybrominated biphenyls (PBBs) (up to 1.1 ng/g ww) and polychlorinated naphthalenes (PCNs, only 4 congeners) (up to 62.7 pg/g ww), were measured in biota from Lake Ellasjoen. In Lake Oyangen, located only 5 km north of Ellasjoen, levels of these contaminants were significantly lower. {delta}{sup 15}N-values were 7-10%o higher in organisms from Ellasjoen as compared to Oyangen. This is attributed to biological inputs related to seabird activities. The present study illustrates that contaminants such as CHBs, brominated flame retardants and PCNs accumulate in the Ellasjoen food web in a manner similar to PCBs and conventional organochlorine pesticides. Transport mechanisms that control PCB and DDT distributions, i.e. atmospheric long-range transport and biotransport by seabirds, are also relevant for the contaminants investigated in the present study. - Elevate levels of chlorobornanes, polychlorinated naphthalenes and brominated flame retardants have been measured in biota from a Norwegian Arctic lake.

  1. Levels and distribution of brominated flame retardants in the soil of Harbin in China

    Institute of Scientific and Technical Information of China (English)

    WANG Xu; REN Nanqi; QI Hong; MA Wanli; LI Yifan

    2009-01-01

    This study reports the presence of brominated flame retardants in the topsoil in and around Harbin,a city in northeastern China.Samples of soil were collected from 17 locations in 2006,and the levels of 9 polybrominated diphenylethers (PBDEs 17,28,47,66,99,100,153,154,and 183) ranged from 2.45 to 55.9 pg/g dry weight (dw) with a mean of 26.3 pg/g dw.These levels are very low compared with those for some cities in Europe and the USA.BDE 209 and hexabromocyclododecane were the two dominant congeners,with mean concentrations of 520 pg/g dw and 1750 pg/g dw,respectively.The concentrations of the total 9 PBDE congeners clearly decreased from urban areas to background,but the compositions of individual congeners differed.Proportions of heavier congeners decreased while those of lighter congeners increased,along urban-rural-background transect,providing evidence for an urban fractionation effect.Correlation analysis indicated similar sources for PBDEs,hexabromocyclododecane,and 1,2-bis(2,4,6-tribromophenoxy)-ethane from urban areas but pentabromoethylbenzene was probably present due to long-range atmospheric transport.Principal component analysis was used to determine the characteristics of the relationships among these brominated flame retardants in the field.

  2. Nitrogenous disinfection byproducts in English drinking water supply systems: Occurrence, bromine substitution and correlation analysis.

    Science.gov (United States)

    Bond, Tom; Templeton, Michael R; Mokhtar Kamal, Nurul Hana; Graham, Nigel; Kanda, Rakesh

    2015-11-15

    Despite the recent focus on nitrogenous disinfection byproducts in drinking water, there is limited occurrence data available for many species. This paper analyses the occurrence of seven haloacetonitriles, three haloacetamides, eight halonitromethanes and cyanogen chloride in 20 English drinking water supply systems. It is the first survey of its type to compare bromine substitution factors (BSFs) between the haloacetamides and haloacetonitriles. Concentrations of the dihalogenated haloacetonitriles and haloacetamides were well correlated. Although median concentrations of these two groups were lower in chloraminated than chlorinated surface waters, median BSFs for both in chloraminated samples were approximately double those in chlorinated samples, which is significant because of the higher reported toxicity of the brominated species. Furthermore, median BSFs were moderately higher for the dihalogenated haloacetamides than for the haloacetonitriles. This indicates that, while the dihalogenated haloacetamides were primarily generated from hydrolysis of the corresponding haloacetonitriles, secondary formation pathways also contributed. Median halonitromethane concentrations were remarkably unchanging for the different types of disinfectants and source waters: 0.1 μg · mgTOC(-1) in all cases. Cyanogen chloride only occurred in a limited number of samples, yet when present its concentrations were higher than the other N-DBPs. Concentrations of cyanogen chloride and the sum of the halonitromethanes were not correlated with any other DBPs.

  3. Towards a biochemical and structural characterisation of the sodium-iodide sym-porter (Nis)

    International Nuclear Information System (INIS)

    Iodide is essential for thyroid hormone biosynthesis in mammals, and therefore for the control of cell metabolism and the development of the central nervous system in the foetus and newborns, but is relatively scarce element in the environment. To ensure its accumulation, the thyroid gland has evolved a remarkably efficient system, the sodium-iodide sym-porter (NIS), that was first characterized at the molecular level 10 years ago (1). NIS is an intrinsic protein mainly located in the basolateral membrane of thyroid follicular cells where it actively transports iodide ions using the sodium gradient as a driving force (2,3). In addition, this transporter has been found in lactating mammary gland, stomach, and salivary glands, and its mRNA was detected in brain, ovaries, testis. To date, the physiological role of NIS in these organs is not yet identified (3,4).The capacity of NIS to mediate the accumulation of radioactive iodide has been exploited for many years in the diagnosis of thyroid cancer as well as for the detection and radiotherapy of derived metastases. Moreover, the presence of NIS in some breast tumours and the possibility to express it by targeted gene therapy in tumour cells where it is not naturally present could also widen its medical application (4-7). In case of accidental contamination, NIS would also be responsible for accumulation of radioisotopes in the thyroid and for their transfer to the milk and the newborn, eventually causing thyroid cancers. This has motivated our research program in the perspective of designing novel specific therapeutics. During the last decade, the gene encoding the thyroid NIS has been identified and sequenced in various species including rat, mouse and human (1, 8). It was also demonstrated that the protein expression and activity are highly regulated both at the transcriptional and post-translational levels (3). A preliminary topological mode could be drawn from the protein sequence. It proposes a general

  4. Iodide Sorption to Clays and the Relationship to the Surface Charge Environment

    Science.gov (United States)

    Miller, A. W.; Wang, Y.

    2011-12-01

    In performance assessments of nuclear waste repositories, iodine-129 is often the major contributor to dose at time scales ≥10,000 years. The breakthrough behavior of iodine is determined by the monovalent, anionic nature and the assumed lack of surface reactivity of the iodide ion. This assumption is corroborated by batch sorption data where iodide sorption to clays is typically very small, and only measurable under specific conditions. This result is consistent with charge repulsion arguments due to the fixed negative charge of clays repelling the anionic iodide. However, in compacted column diffusion experiments, iodide is routinely retarded relative to tritium, and is described with Kd values from ≈0.001-2.9ml/g. While small, these values can dramatically change the dose profile in performance assessment calculations. We hypothesize that contributions from the basal plane and edge charge of individual clay particles as well as the physical morphology of the clay particles are contributing to the conflicting behavior. In a series of experiments involving a wide range of clay minerals from the clay bank repository, both surface charge and iodide sorption were examined using surface titrations and batch sorption experiments. The clay minerals studied include: kaolinite, ripidolite, illite, montmorillonite, palygorskite, sepiolite, and an illite/smectite mixed layer clay. Each of these clays was characterized using XRD, and surface titrations in 0.01, 0.1, and 0.5 M NaCl electrolyte. The titrations spanned the pH range from 2.5-10.5 and were automated using an autotitrator. For reference, similar titrations were performed on pure forms of an Al-O powder. The titration curves were interpreted using an inversion method to attain the pKa distribution for each clay and metal oxide at each ionic strength. The pKa distribution for the Al-O shows two distinct peaks at 4.8 and 7.5, which are invariant with ionic strength. The pKa distribution of clays was highly

  5. Distribution and leaching of methyl iodide in soil following emulated shank and drip application.

    Science.gov (United States)

    Guo, Mingxin; Zheng, Wei; Papiernik, Sharon K; Yates, Scott R

    2004-01-01

    Methyl iodide (MeI) is a promising alternative to methyl bromide in soil fumigation. The pest-control efficacy and ground water contamination risks of MeI as a fumigant are highly related to its gas-phase distribution and leaching after soil application. In this study, the distribution and leaching of MeI in soil following shank injection and subsurface drip application were investigated. Methyl iodide (200 kg ha(-1)) was directly injected or drip-applied at a 20-cm depth into Arlington sandy loam (coarse-loamy, mixed, thermic Haplic Durixeralfs) columns (12-cm i.d., 70-cm height) tarped with virtually impermeable film. Concentration profiles of MeI in the soil air were monitored for 7 d. Methyl iodide diffused rapidly after soil application, and reached a 70-cm depth within 2 h. Relative to shank injection, drip application inhibited diffusion, resulting in significantly lower concentration profiles in the soil air. Seven days after MeI application, fumigated soil was uncapped, aerated for 7 d, and leached with water. Leaching of MeI was significant from the soil columns under both application methods, with concentrations of >10 mug L(-1) in the early leachate. The leaching was greater following shank injection than drip application, with an overall potential of 33 g ha(-1) for shank injection and 19 g ha(-1) for drip application. Persistent residues of MeI remaining in soils after leaching were 50 to 240 ng kg(-1), and the contents were slightly higher following shank injection than drip application. The results suggest that fumigation with MeI may pose a risk of ground water contamination in vulnerable areas. PMID:15537937

  6. Equations of state for crystalline zirconium iodide: The role of dispersion

    Science.gov (United States)

    Rossi, Matthew L.; Taylor, Christopher D.

    2013-02-01

    We present the first-principle equations of state of several zirconium iodides, ZrI2, ZrI3, and ZrI4, computed using density functional theory methods that apply various methods for introducing the dispersion correction. Iodides formed due to reaction of molecular or atomic iodine with zirconium and zircaloys are of particular interest due to their application to the cladding material used in the fabrication of nuclear fuel rods. Stress corrosion cracking (SCC), associated with fission product chemistry with the clad material, is a major concern in the life cycle of nuclear fuels, as many of the observed rod failures have occurred due to pellet-cladding chemical interactions (PCCI) [A. Atrens, G. Dannhäuser, G. Bäro, Stress-corrosion-cracking of zircaloy-4 cladding tubes, Journal of Nuclear Materials 126 (1984) 91-102; P. Rudling, R. Adamson, B. Cox, F. Garzarolli, A. Strasser, High burn-up fuel issues, Nuclear Engineering and Technology 40 (2008) 1-8]. A proper understanding of the physical properties of the corrosion products is, therefore, required for the development of a comprehensive SCC model. In this particular work, we emphasize that, while existing modeling techniques include methods to compute crystal structures and associated properties, it is important to capture intermolecular forces not traditionally included, such as van der Waals (dispersion) correction. Furthermore, crystal structures with stoichiometries favoring a high I:Zr ratio are found to be particularly sensitive, such that traditional density functional theory approaches that do not incorporate dispersion incorrectly predict significantly larger volumes of the lattice. This latter point is related to the diffuse nature of the iodide electron cloud.

  7. Phase partitioning, retention kinetics, and leaching of fumigant methyl iodide in agricultural soils

    International Nuclear Information System (INIS)

    Although it is not currently being sold in the USA, the recent US registration of the fumigant methyl iodide has led to an increased interest in its environmental fate and transport. Although some work has now considered its volatile emissions from soil, there remains a lack of experimental data regarding its ability to be retained in soil and ultimately become transported with irrigation/rain waters. Using laboratory batch and soil column experiments, we aimed to better understand the phase partitioning of MeI, the ability of soils to retain MeI on the solid phase, and the potential for leaching of MeI and its primary degradation product, iodide, down a soil profile. Results indicated that MeI was retained by the solid phase of soil, being protected from volatilization and degradation, particularly in the presence of elevated organic matter. Retention was greater at lower moisture content, and maximum retention occurred after 56 days of incubation. At higher moisture content, the liquid phase also became important in retaining MeI within soil. Together with low observed KD values (0.10 to 0.57 mL g−1), these data suggest that MeI may be prone to leaching. Indeed, in a steady-state soil column study, initially retained MeI was transported with interstitial water. The MeI degradation product, iodide, was also readily transported in this manner. The data highlight a potentially significant process by which MeI fate and transport within the environment may be impacted. -- Highlights: ► Following fumigation and venting, MeI is retained by soil. ► Soil organic matter status is highly significant in MeI retention. ► Retained MeI is protected from degradation and volatilization. ► Retained MeI can be removed from the solid phase to the liquid phase and leached.

  8. Prenatal Exposure to Organohalogens, Including Brominated Flame Retardants, Influences Motor, Cognitive, and Behavioral Performance at School Age

    NARCIS (Netherlands)

    Roze, Elise; Meijer, Lisethe; Bakker, Attie; Van Braeckel, Koenraad N. J. A.; Sauer, Pieter J. J.; Bos, Arend F.

    2009-01-01

    BACKGROUND: Organohalogen compounds (OHCs) are known to have neurotoxic effects on the developing brain. OBJECTIVE: We investigated the influence of prenatal exposure to OHCs, including brominated flame retardants, on motor, cognitive, and behavioral outcome in healthy children of school age. METHOD

  9. Different speciation for bromine in brown and red algae, revealed by in vivo X-ray absorption spectroscopic studies.

    Science.gov (United States)

    Küpper, Frithjof C; Leblanc, Catherine; Meyer-Klaucke, Wolfram; Potin, Philippe; Feiters, Martin C

    2014-08-01

    Members of various algal lineages are known to be strong producers of atmospherically relevant halogen emissions, that is a consequence of their capability to store and metabolize halogens. This study uses a noninvasive, synchrotron-based technique, X-ray absorption spectroscopy, for addressing in vivo bromine speciation in the brown algae Ectocarpus siliculosus, Ascophyllum nodosum, and Fucus serratus, the red algae Gracilaria dura, G. gracilis, Chondrus crispus, Osmundea pinnatifida, Asparagopsis armata, Polysiphonia elongata, and Corallina officinalis, the diatom Thalassiosira rotula, the dinoflagellate Lingulodinium polyedrum and a natural phytoplankton sample. The results highlight a diversity of fundamentally different bromine storage modes: while most of the stramenopile representatives and the dinoflagellate store mostly bromide, there is evidence for Br incorporated in nonaromatic hydrocarbons in Thalassiosira. Red algae operate various organic bromine stores - including a possible precursor (by the haloform reaction) for bromoform in Asparagopsis and aromatically bound Br in Polysiphonia and Corallina. Large fractions of the bromine in the red algae G. dura and C. crispus and the brown alga F. serratus are present as Br(-) defects in solid KCl, similar to what was reported earlier for Laminaria parts. These results are discussed according to different defensive strategies that are used within algal taxa to cope with biotic or abiotic stresses. PMID:26988449

  10. Rapid Formation of Molecular Bromine from Deliquesced NaBr Aerosol in the Presence of Ozone and UV Light

    Science.gov (United States)

    The formation of gas-phase bromine from aqueous sodium bromide aerosols is investigated through a combination of chamber experiments and chemical kinetics modeling. Experiments show that Br2(g) is produced rapidly from deliquesced NaBr aerosols in the presence of OH radicals prod...

  11. Corrosion mechanism of 13Cr stainless steel in completion fluid of high temperature and high concentration bromine salt

    International Nuclear Information System (INIS)

    Highlights: • The corrosion behavior of 13Cr steel exposed to bromine salt completion fluid containing high concentration bromine ions was investigated. • There are passive circles around pits on the 13Cr steel surface after 7 d of exposure. • Macroscopic galvanic corrosion formed between the passive halo and the pit. • The mechanism of pitting corrosion on 13Cr stainless steel exposed to heavy bromine brine was established. - Abstract: A series of corrosion tests of 13Cr stainless steel were conducted in a simulated completion fluid environment of high temperature and high concentration bromine salt. Corrosion behavior of specimens and the component of corrosion products were investigated by means of scanning electron microscope (SEM), confocal laser scanning microscopy (CLSM) and X-ray photoelectron spectroscopy (XPS). The results indicate that 13Cr steel suffers from severe local corrosion and there is always a passive halo around every pit. The formation mechanism of the passive halo is established. OH− ligand generates and adsorbs in a certain scale because of abundant OH− on the surface around the pits. Passive film forms around each pit, which leads to the occurrence of passivation in a certain region. Finally, the dissimilarities in properties and morphologies of regions, namely the pit and its corresponding passive halo, can result in different corrosion sensitivities and may promote the formation of macroscopic galvanic pairs

  12. Exposure to brominated trihalomethanes in water during pregnancy and micronuclei frequency in maternal and cord blood lymphocytes

    DEFF Research Database (Denmark)

    Stayner, Leslie Thomas; Pedersen, Marie; Patelarou, Evridiki;

    2014-01-01

    BACKGROUND: Water disinfection by-products have been associated with an increased cancer risk. Micronuclei (MN) frequency in lymphocytes is a marker of genomic damage and can predict adult cancer risk. OBJECTIVE: We evaluated maternal exposure to drinking water brominated trihalomethanes (BTHM) i...

  13. Bromination of Aromatic Compounds by Residual Bromide in Sodium Chloride Matrix Modifier Salt During Heated Headspace GC/MS Analysis

    Science.gov (United States)

    Analytical artifacts attributed to the bromination of toluene, xylenes, and trimethylbenzenes were found during the heated headspace gas chromatography/mass spectrometry (GC/MS) analysis of aqueous samples. The aqueous samples were produced from Fenton-like chemical oxidation rea...

  14. Accumulation of organochlorines and brominated flame retardants in estuarine and marine food chains: Field measurements and model calculations

    NARCIS (Netherlands)

    Veltman, K.; Hendriks, J.; Huijbregts, M.; Leonards, P.E.G.; Heuvel-Greve, van den M.J.; Vethaak, D.

    2005-01-01

    Food chain accumulation of organochlorines and brominated flame retardants in estuarine and marine environments is compared to model estimations and fresh water field data. The food chain consists of herbivores, detritivores and primary and secondary carnivores i.e. fish, fish-eating birds and marin

  15. Subacute effects of the brominated flame retardants hexabromocyclododecane and tetrabromobisphenol A on hepatic cytochrome P450 levels in rats.

    NARCIS (Netherlands)

    Germer, Silke; Piersma, Aldert H; Ven, Leo T M van der; Kamyschnikow, Andreas; Fery, Yvonne; Schmitz, Hans-Joachim; Schrenk, Dieter

    2006-01-01

    The brominated flame retardants tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCD) are found in the environment, e.g., in sediments and organisms, in food items, human blood samples and mother's milk. In this study, the effects of both compounds on rat hepatic cytochrome P450 (CYP) leve

  16. Corrosion mechanism of 13Cr stainless steel in completion fluid of high temperature and high concentration bromine salt

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yan [Corrosion and Protection Center, Key Laboratory for Environmental Fracture (MOE), Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083 (China); Xu, Lining, E-mail: xulining@ustb.edu.cn [Corrosion and Protection Center, Key Laboratory for Environmental Fracture (MOE), Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083 (China); Lu, Minxu [Corrosion and Protection Center, Key Laboratory for Environmental Fracture (MOE), Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083 (China); Meng, Yao [Beijing Institute of Aeronautical Materials, Beijing 100095 (China); Zhu, Jinyang; Zhang, Lei [Corrosion and Protection Center, Key Laboratory for Environmental Fracture (MOE), Institute for Advanced Materials and Technology, University of Science and Technology Beijing, Beijing 100083 (China)

    2014-09-30

    Highlights: • The corrosion behavior of 13Cr steel exposed to bromine salt completion fluid containing high concentration bromine ions was investigated. • There are passive circles around pits on the 13Cr steel surface after 7 d of exposure. • Macroscopic galvanic corrosion formed between the passive halo and the pit. • The mechanism of pitting corrosion on 13Cr stainless steel exposed to heavy bromine brine was established. - Abstract: A series of corrosion tests of 13Cr stainless steel were conducted in a simulated completion fluid environment of high temperature and high concentration bromine salt. Corrosion behavior of specimens and the component of corrosion products were investigated by means of scanning electron microscope (SEM), confocal laser scanning microscopy (CLSM) and X-ray photoelectron spectroscopy (XPS). The results indicate that 13Cr steel suffers from severe local corrosion and there is always a passive halo around every pit. The formation mechanism of the passive halo is established. OH{sup −} ligand generates and adsorbs in a certain scale because of abundant OH{sup −} on the surface around the pits. Passive film forms around each pit, which leads to the occurrence of passivation in a certain region. Finally, the dissimilarities in properties and morphologies of regions, namely the pit and its corresponding passive halo, can result in different corrosion sensitivities and may promote the formation of macroscopic galvanic pairs.

  17. Electrical properties of solid iodo mercurates resulting from the reaction of HgI2 with alcaline iodides

    Science.gov (United States)

    Ponpon, J. P.; Amann, M.

    2005-01-01

    Potassium iodide solutions are currently used during the fabrication process of mercuric iodide based nuclear radiation detectors. However, KI treatment leaves the HgI2 surface covered with a residual compound (namely the potassium tri-iodo mercurate) which has a significant influence on the surface properties and stability of mercuric iodide devices and therefore on the detectors characteristics. Looking for other solutions to etch mercuric iodide, we found it interesting to investigate the electrical properties of the compounds which may form when etching HgI2 in NH4I, NaI, and RbI. For this purpose, solid iodo mercurates with the cations ammonium, sodium, and rubidium, have been prepared by reacting HgI2 with the solutions of interest. Study of the electrical properties of these samples and comparison with those of potassium tri-iodo mercurate ones, especially with respect to humidity, indicates noticeable stability differences in presence of water vapour. This could have interesting consequences on the surface cleaning of mercuric iodide.

  18. Efficient radiation production in a weakly ionized, low-pressure, nonequilibrium gallium-iodide positive column discharge plasma

    Energy Technology Data Exchange (ETDEWEB)

    Smith, David J; Michael, J Darryl; Midha, Vikas; Cotzas, George M; Sommerer, Timothy J [General Electric Research, One Research Circle, Niskayuna, NY 12309 (United States)

    2007-07-07

    Electric-discharge plasmas in gallium-iodide vapours are experimentally found to convert 40% of input electric power into ultraviolet and visible radiation (200-800 nm). The conditions are a weakly ionized positive column consisting of 5-10 Torr argon, and the gallium-iodide vapour is formed by heating condensed gallium-iodide to 100-120 deg. C. The input power density is 50-100 mW cm{sup -3}. The plasma is contained in a sealed silica tube and excited by an external radiofrequency antenna. Computational analysis and plasma diagnostics lead to a quantitative understanding that gallium atoms are formed by electron-impact dissociation of gallium-iodide compounds that evaporate into the plasma volume, and that further electron collisions excite the gallium atoms, which then decay by photon emission. High efficiency is possible only because several photons are emitted per dissociation event, and because nonradiative power channels such as electron-impact elastic heating and vibrational excitation are not dominant. The dissociated species recombine on the wall to reform the species that evaporates. The plasma properties change discontinuously as the molar ratio of iodine to gallium (I/Ga) in the system crosses the values I/Ga = 3 and I/Ga = 2, consistent with the thermodynamic properties of condensed gallium-iodide compounds.

  19. Synergy between iodide ions and mangrove tannins as inhibitors of mild steel corrosion

    OpenAIRE

    Adam, Mohd Ridhwan; Rahim, Afidah Abdul; Shah, Affaizza Mohamad

    2015-01-01

    Context Corrosion of materials is a problem faced by many industries. One of the solutions to this problem is to apply corrosion inhibitors.Aims In this study, the synergy between iodide ions and mangrove tannin extracted from mangrove bark (waste products of the charcoal industry) was tested on the inhibition of corrosion of mild steel in 0.5 M HCl and 0.25 M H2SO4. It was compared with the inhibition provided by mimosa and chestnut tannins.MethodsPotentiodynamic and electrochemical impedanc...

  20. Indirect Complexometric Determination of Mercury Using Potassium Iodide as Selective Masking Agent

    OpenAIRE

    RAO, B. Muralidhara

    1998-01-01

    This paper describes a indirect complexometric method for the determination of mercury in the presence of co-ions, based on the selective masking ability of potassium iodide. To the mixture of mercury (II) and other metal ion solution, EDTA solution was added in excess of the metal ions present. The pH of the solution was adjusted to 5.0-6.0 using solid hexamine (10 \\pm 2 g) and surplus EDTA was titrated with zinc sulfate solution using xylenol orange indicator. An excess of solid potassium i...

  1. Introduction to fifth international workshop on mercuric iodide nuclear radiation detectors

    International Nuclear Information System (INIS)

    Mercuric iodide is a wide bandgap semiconductor, with Eg approx. = 2.14 eV at room temperature. Therefore, HgI2 is totally different from the well-studied, narrower gap, elemental semiconductors such as Si and Ge, and also different in its physical and chemical properties from the known semiconductor binary zinc-blend compounds such as GaAs or InP. The purpose of studies in the last decade was to further our understanding of HgI2; recent progress is reported

  2. Detection of experimentally produced acute pulmonary arterial occlusion by methyl iodide-131 inhalation imaging

    International Nuclear Information System (INIS)

    Methyl iodide-131 (CH3I-131) is described as an agent for detection of acute experimentally produced pulmonary arterial occlusion in dogs. When gaseous CH3I-131 is inhaled, radioactivity passes instantaneously from the alveoli to the lung capillary bed. Where pulmonary blood flow exists, activity is washed out into the systemic circulation, but in areas of blood stasis, a transient pulmonary hot spot remains. CH3I-131 is easily produced and inexpensive, but administration is awkward and strict radiation safety precautions are mandatory

  3. Atypical cutaneous sporotrichosis in an immunocompetent adult: Response to potassium iodide

    Directory of Open Access Journals (Sweden)

    Nikita Gandhi

    2016-01-01

    Full Text Available Cutaneous sporotrichosis, also known as “Rose Gardener's disease,” caused by dimorphic fungus Sporothrix schenkii, is usually characterized by indolent nodular or nodulo-ulcerative lesions arranged in a linear pattern. We report bizarre nonlinear presentation of Sporotrichosis, in an immunocompetent adult occurring after a visit to Amazon rain forest, speculating infection with more virulent species of Sporothrix. The diagnosis was reached with the help of periodic acid-Schiff positive yeast cells and cigar shaped bodies seen in skin biopsy along with the therapeutic response to potassium iodide.

  4. A study on sodium iodide symporter gene mutation in congenital hypothyroidism

    International Nuclear Information System (INIS)

    Objective: To investigate the mutation of sodium iodide symporter (NIS) gene in the patients with congenital hypothyroidism (CH) in Tianjin area. Methods: Total genomic DNA was extracted from peripheral blood of 18 patients with CH and 35 normal subjects randomly selected. All 15 exons of NIS gene were individually amplified. Mutation was detected by single-strand conformational polymorphism(SSCP) technique and confirmed with direct sequencing. Results: Exons of NIS gene of all the subjects were successfully amplified by polymerase chain reaction. SSCP analysis displayed no abnormality. No mutation was found in these patients Conclusion: The CH in Tianjin urban area had no mutation of NIS gene. (authors)

  5. Towards Renewable Iodide Sources for Electrolytes in Dye-Sensitized Solar Cells

    Directory of Open Access Journals (Sweden)

    Iryna Sagaidak

    2016-03-01

    Full Text Available A novel family of iodide salts and ionic liquids based on different carbohydrate core units is herein described for application in dye-sensitized solar cell (DSC. The influence of the molecular skeleton and the cationic structure on the electrolyte properties, device performance and on interfacial charge transfer has been investigated. In combination with the C106 polypyridyl ruthenium sensitizer, power conversion efficiencies lying between 5.0% and 7.3% under standard Air Mass (A.M. 1.5G conditions were obtained in association with a low volatile methoxypropionitrile (MPN-based electrolyte.

  6. Introduction to fifth international workshop on mercuric iodide nuclear radiation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Schieber, M.

    1982-01-01

    Mercuric iodide is a wide bandgap semiconductor, with Eg approx. = 2.14 eV at room temperature. Therefore, HgI/sub 2/ is totally different from the well-studied, narrower gap, elemental semiconductors such as Si and Ge, and also different in its physical and chemical properties from the known semiconductor binary zinc-blend compounds such as GaAs or InP. The purpose of studies in the last decade was to further our understanding of HgI/sub 2/; recent progress is reported. (WHK)

  7. Reaction of bromine and chlorine with phenolic compounds and natural organic matter extracts--Electrophilic aromatic substitution and oxidation.

    Science.gov (United States)

    Criquet, Justine; Rodriguez, Eva M; Allard, Sebastien; Wellauer, Sven; Salhi, Elisabeth; Joll, Cynthia A; von Gunten, Urs

    2015-11-15

    Phenolic compounds are known structural moieties of natural organic matter (NOM), and their reactivity is a key parameter for understanding the reactivity of NOM and the disinfection by-product formation during oxidative water treatment. In this study, species-specific and/or apparent second order rate constants and mechanisms for the reactions of bromine and chlorine have been determined for various phenolic compounds (phenol, resorcinol, catechol, hydroquinone, phloroglucinol, bisphenol A, p-hydroxybenzoic acid, gallic acid, hesperetin and tannic acid) and flavone. The reactivity of bromine with phenolic compounds is very high, with apparent second order rate constants at pH 7 in the range of 10(4) to 10(7) M(-1) s(-1). The highest value was recorded for the reaction between HOBr and the fully deprotonated resorcinol (k = 2.1 × 10(9) M(-1) s(-1)). The reactivity of phenolic compounds is enhanced by the activating character of the phenolic substituents, e.g. further hydroxyl groups. With the data set from this study, the ratio between the species-specific rate constants for the reactions of chlorine versus bromine with phenolic compounds was confirmed to be about 3000. Phenolic compounds react with bromine or chlorine either by oxidation (electron transfer, ET) or electrophilic aromatic substitution (EAS) processes. The dominant process mainly depends on the relative position of the hydroxyl substituents and the possibility of quinone formation. While phenol, p-hydroxybenzoic acid and bisphenol A undergo EAS, hydroquinone, catechol, gallic acid and tannic acid, with hydroxyl substituents in ortho or para positions, react with bromine by ET leading to quantitative formation of the corresponding quinones. Some compounds (e.g. phloroglucinol) show both partial oxidation and partial electrophilic aromatic substitution and the ratio observed for the pathways depends on the pH. For the reaction of six NOM extracts with bromine, electrophilic aromatic substitution

  8. Investigating the lifetime of bromine-quenched G.M. Counters with temperature

    Science.gov (United States)

    Abilama, Marc; Bates, Mike; Lohstroh, Annika

    2015-09-01

    The amount of halogen quench gas as a percentage of the total fill gas contained within a gas-filled Geiger-Müller detector is directly linked to its operational characteristics. Preserving this halogen gas will help maintain the operating lifetime of the detectors. Such halogen gases are highly corrosive and the small quantities within a gas-filled detector can deplete rapidly via interactions with surrounding materials. The rate of interactions is thought to be proportional to not only temperature, but also to the current initiated by ionisation events associated with the formation of each signal pulse. As all pulses are of similar magnitudes, GM detector operational lifetimes are quantified in accumulated counts rather than a given operating time. We have studied three different types of corrosion-resistant mechanisms to protect the bromine halogen gas from any interactions with 446 stainless steel detector components of ZP1200 Geiger-Müller tubes at temperatures up to 125 °C. Three types of surface treatments for these detectors used were labelled as "raw" using only an oxygen-plasma-bombardment process, "passivated" using a combination of nitric acid passivation followed by an oxygen plasma-bombardment process, and thirdly plating with a few micron thickness of chromium followed by an oxygen plasma-bombardment process. 32 detector samples were irradiated at room temperature with a Caesium-137 source at dose rates of approximately 1.3 mSv/hr up to 5.7×1010 accumulated counts; another 32 detector samples were aged to 3.3×1010 counts at 125 °C. At room temperature, the chromium-plated samples exhibited an initial rise in their starting voltage readings. All other detector performance characteristics, for all detector types, did not change significantly during the ageing process, and the surface morphology of the detector cathodes was unaffected. At 125 °C, the chromium-based plating produced the most stable long-term response. These chromium-plated samples

  9. Mercury oxidation from bromine chemistry in the free troposphere over the southeastern US

    Directory of Open Access Journals (Sweden)

    S. Coburn

    2015-10-01

    Full Text Available The elevated deposition of atmospheric mercury over the Southeastern United States is currently not well understood. Here we measure partial columns and vertical profiles of bromine monoxide (BrO radicals, a key component of mercury oxidation chemistry, to better understand the processes and altitudes at which mercury is being oxidized in the atmosphere. We use the data from a ground-based MAX-DOAS instrument located at a coastal site ~ 1 km from the Gulf of Mexico in Gulf Breeze, FL, where we had previously detected tropospheric BrO (Coburn et al., 2011. Our profile retrieval assimilates information about stratospheric BrO from the WACCM chemical transport model, and uses only measurements at moderately low solar zenith angles (SZA to estimate the BrO slant column density contained in the reference spectrum (SCDRef. The approach has 2.6 degrees of freedom, and avoids spectroscopic complications that arise at high SZA; knowledge about SCDRef helps to maximize sensitivity in the free troposphere (FT. A cloud-free case study day with low aerosol load (9 April 2010 provided optimal conditions for distinguishing marine boundary layer (MBL: 0–1 km and free tropospheric (FT: 1–15 km BrO from the ground. The average daytime tropospheric BrO vertical column density (VCD of ~ 2.3 × 1013 molec cm−2 (SZA 5 molec cm−2 s−1 for bromine, while contributions from ozone (O3 and chlorine (Cl were 0.9 × 105 and 0.2 × 105 molec cm−2 s−1, respectively. The GOM formation rate is sensitive to recently proposed atmospheric scavenging reactions of the HgBr adduct by nitrogen dioxide (NO2, and to a lesser extent also HO2 radicals. Using a 3-D chemical transport model, we find that surface GOM variations are typical also of other days, and are mainly derived from the free troposphere. Bromine chemistry is active in the FT over Gulf Breeze, where it forms water-soluble GOM that is subsequently available for wet scavenging by thunderstorms or transport to

  10. Bromine release during Plinian eruptions along the Central American Volcanic Arc

    Science.gov (United States)

    Hansteen, T. H.; Kutterolf, S.; Appel, K.; Freundt, A.; Perez-Fernandez, W.; Wehrmann, H.

    2010-12-01

    Volcanoes of the Central American Volcanic Arc (CAVA) have produced at least 72 highly explosive eruptions within the last 200 ka. The eruption columns of all these “Plinian” eruptions reached well into the stratosphere such that their released volatiles may have influenced atmospheric chemistry and climate. While previous research has focussed on the sulfur and chlorine emissions during such large eruptions, we here present measurements of the heavy halogen bromine by means of synchrotron radiation induced micro-XRF microanalysis (SR-XRF) with typical detection limits at 0.3 ppm (in Fe rich standard basalt ML3B glass). Spot analyses of pre-eruptive glass inclusions trapped in minerals formed in magma reservoirs were compared with those in matrix glasses of the tephras, which represent the post-eruptive, degassed concentrations. The concentration difference between inclusions and matrix glasses, multiplied by erupted magma mass determined by extensive field mapping, yields estimates of the degassed mass of bromine. Br is probably hundreds of times more effective in destroying ozone than Cl, and can accumulate in the stratosphere over significant time scales. Melt inclusions representing deposits of 22 large eruptions along the CAVA have Br contents between 0.5 and 13 ppm. Br concentrations in matrix glasses are nearly constant at 0.4 to 1.5 ppm. However, Br concentrations and Cl/Br ratios vary along the CAVA. The highest values of Br contents (>8 ppm) and lowest Cl/Br ratios (170 to 600) in melt inclusions occur across central Nicaragua and southern El Salvador, and correlate with bulk-rock compositions of high Ba/La > 85 as well as low La/Yb discharged 700 kilotons of Br. On average, each of the remaining 21 CAVA eruptions studied have discharged c.100 kilotons of bromine. During the past 200 ka, CAVA volcanoes have emitted a cumulative mass of 3.2 Mt of Br through highly explosive eruptions. There are six periods in the past (c. 2ka, 6ka, 25ka, 40ka, 60ka, 75

  11. Molecular simulations and density functional theory calculations of bromine in clathrate hydrate phases

    Energy Technology Data Exchange (ETDEWEB)

    Dureckova, Hana, E-mail: houci059@uottawa.ca; Woo, Tom K., E-mail: tom.woo@uottawa.ca [Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 5N6 (Canada); Alavi, Saman, E-mail: saman.alavi@nrc-cnrc.gc.ca [Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, Ontario K1N 5N6 (Canada); National Research Council of Canada, 100 Sussex Dr., Ottawa, Ontario K1N 6N5 (Canada); Department of Chemical and Biological Engineering, University of British Columbia, Vancouver, British Columbia V6T 1Z3 (Canada)

    2016-01-28

    Bromine forms a tetragonal clathrate hydrate structure (TS-I) very rarely observed in clathrate hydrates of other guest substances. The detailed structure, energetics, and dynamics of Br{sub 2} and Cl{sub 2} in TS-I and cubic structure I (CS-I) clathrate hydrates are studied in this work using molecular dynamics and quantum chemical calculations. X-ray diffraction studies show that the halogen-water–oxygen distances in the cages of these structures are shorter than the sum of the van der Waals radii of halogen and oxygen atoms. This suggests that the stabilizing effects of halogen bonding or other non-covalent interactions (NCIs) may contribute to the formation of the unique tetragonal bromine hydrate structure. We performed molecular dynamics simulations of Br{sub 2} and Cl{sub 2} clathrate hydrates using our previously developed five-site charge models for the dihalogen molecules [Dureckova et al. Can. J. Chem. 93, 864 (2015)] which reproduce the computed electrostatic potentials of the dihalogens and account for the electropositive σ-hole of the halogen bond donor (the dihalogen). Analysis of the radial distribution functions, enthalpies of encapsulation, velocity and orientation autocorrelation functions, and polar angle distributions are carried out for Br{sub 2} and Cl{sub 2} guests in various cages to contrast the properties of these guests in the TS-I and CS-I phases. Quantum chemical partial geometry optimizations of Br{sub 2} and Cl{sub 2} guests in the hydrate cages using the M06-2X functional give short halogen-water distances compatible with values observed in X-ray diffraction experiments. NCI plots of guest-cage structures are generated to qualitatively show the relative strength of the non-bonding interactions between dihalogens and water molecules. The differences between behaviors of Br{sub 2} and Cl{sub 2} guests in the hydrate cages may explain why bromine forms the unique TS-I phase.

  12. Seasonal variation of bromine monoxide over the Rann of Kutch salt marsh seen from space

    Science.gov (United States)

    Hörmann, Christoph; Beirle, Steffen; Penning de Vries, Marloes; Sihler, Holger; Platt, Ulrich; Wagner, Thomas

    2015-04-01

    Bromine monoxide (BrO) is an important catalyst in the depletion of tropospheric and stratospheric ozone (O3). In the troposphere, reactive bromine can be released from sea ice, volcanoes, sea-salt aerosol or salt lakes. For all of these natural sources enhanced BrO vertical column densities (VCDs) have been successfully observed from ground using Differential Optical Absorption Spectroscopy (DOAS). Until now, satellite observations were only reported for polar regions during springtime and volcanic emissions (mostly for major eruptions). We present the first satellite observations of enhanced monthly mean BrO VCDs over a salt marsh, the Rann of Kutch (India/Pakistan), during 2004-2014 as seen by the Ozone Monitoring Instrument (OMI). The Rann of Kutch is a so-called 'seasonal' salt marsh. During India's summer monsoon (June/July - September/October), the flat desert of salty clay and mudflats, which average 15 meters above sea level, fills with standing rain and sea water. With more than 7500 km2 it is the largest salt desert in the world and additionally one of the hottest areas of India with summer temperatures around 50 ° C and winter temperatures decreasing below 0 ° C. Probably due to these rather extreme conditions, the Rann of Kutch has not been yet investigated for atmospheric composition measurements by ground-based instruments. Satellite observations, however, provide the unique possibility to investigate the entire area remotely over a long-time period. The OMI data reveals recurring maximum BrO VCDs during April/May, but no enhanced column densities during the monsoon season while the area is flooded. In the following months the signal only recovers slowly while the salty surface dries up. We discuss the possible effects of temperature, precipitation and relative humidity on the release of enhanced reactive bromine concentrations. In order to investigate a possible diurnal cycle of the BrO concentration, the OMI results (at a local overflight time

  13. Investigating the lifetime of bromine-quenched G.M. Counters with temperature

    Energy Technology Data Exchange (ETDEWEB)

    Abilama, Marc [Centronic Ltd., Croydon (United Kingdom); University of Surrey, Guildford (United Kingdom); Bates, Mike [Centronic Ltd., Croydon (United Kingdom); Lohstroh, Annika [University of Surrey, Guildford (United Kingdom)

    2015-09-21

    The amount of halogen quench gas as a percentage of the total fill gas contained within a gas-filled Geiger–Müller detector is directly linked to its operational characteristics. Preserving this halogen gas will help maintain the operating lifetime of the detectors. Such halogen gases are highly corrosive and the small quantities within a gas-filled detector can deplete rapidly via interactions with surrounding materials. The rate of interactions is thought to be proportional to not only temperature, but also to the current initiated by ionisation events associated with the formation of each signal pulse. As all pulses are of similar magnitudes, GM detector operational lifetimes are quantified in accumulated counts rather than a given operating time. We have studied three different types of corrosion-resistant mechanisms to protect the bromine halogen gas from any interactions with 446 stainless steel detector components of ZP1200 Geiger–Müller tubes at temperatures up to 125 °C. Three types of surface treatments for these detectors used were labelled as “raw” using only an oxygen-plasma-bombardment process, “passivated” using a combination of nitric acid passivation followed by an oxygen plasma-bombardment process, and thirdly plating with a few micron thickness of chromium followed by an oxygen plasma-bombardment process. 32 detector samples were irradiated at room temperature with a Caesium-137 source at dose rates of approximately 1.3 mSv/hr up to 5.7×10{sup 10} accumulated counts; another 32 detector samples were aged to 3.3×10{sup 10} counts at 125 °C. At room temperature, the chromium-plated samples exhibited an initial rise in their starting voltage readings. All other detector performance characteristics, for all detector types, did not change significantly during the ageing process, and the surface morphology of the detector cathodes was unaffected. At 125 °C, the chromium-based plating produced the most stable long-term response. These

  14. Zinc iodide-osmium staining of membrane-coating granules in keratinized and non-keratinized mammalian oral epithelium.

    Science.gov (United States)

    Squier, C A

    1982-01-01

    Specimens of keratinized and non-keratinized oral epithelium were examined in the electron microscope after being stained with zinc iodide-osmium. In both types of tissue, reaction was seen in unmyelinated nerves, in the specific granules of epithelial Langerhans cells and within lysosome-like organelles and small vesicles associated with Golgi systems. In keratinized epithelia, the reaction was also present in the membrane-coating granules and between the deepest cells of the keratinized layer. In contrast, the membrane-coating granules of non-keratinized epithelia lacked Zn iodide-osmium staining despite the presence of reaction in adjacent Golgi systems. It is suggested that Zn iodide-osmium stains glycolipid or glycoprotein material in the cell. This material is elaborated in the Golgi systems from which lysosomes and the membrane-coating granules of keratinized tissues are probably derived.

  15. Air-snowpack exchange of bromine, ozone and mercury in the springtime Arctic simulated by the 1-D model PHANTAS - Part 1: In-snow bromine activation and its impact on ozone

    Science.gov (United States)

    Toyota, K.; McConnell, J. C.; Staebler, R. M.; Dastoor, A. P.

    2014-04-01

    To provide a theoretical framework towards a better understanding of ozone depletion events (ODEs) and atmospheric mercury depletion events (AMDEs) in the polar boundary layer, we have developed a one-dimensional model that simulates multiphase chemistry and transport of trace constituents from porous snowpack and through the atmospheric boundary layer (ABL) as a unified system. This paper constitutes Part 1 of the study, describing a general configuration of the model and the results of simulations related to reactive bromine release from the snowpack and ODEs during the Arctic spring. A common set of aqueous-phase reactions describes chemistry both within the liquid-like layer (LLL) on the grain surface of the snowpack and within deliquesced "haze" aerosols mainly composed of sulfate in the atmosphere. Gas-phase reactions are also represented by the same mechanism in the atmosphere and in the snowpack interstitial air (SIA). Consequently, the model attains the capacity of simulating interactions between chemistry and mass transfer that become particularly intricate near the interface between the atmosphere and the snowpack. In the SIA, reactive uptake on LLL-coated snow grains and vertical mass transfer act simultaneously on gaseous HOBr, a fraction of which enters from the atmosphere while another fraction is formed via gas-phase chemistry in the SIA itself. A "bromine explosion", by which HOBr formed in the ambient air is deposited and then converted heterogeneously to Br2, is found to be a dominant process of reactive bromine formation in the top 1 mm layer of the snowpack. Deeper in the snowpack, HOBr formed within the SIA leads to an in-snow bromine explosion, but a significant fraction of Br2 is also produced via aqueous radical chemistry in the LLL on the surface of the snow grains. These top- and deeper-layer productions of Br2 both contribute to the release of Br2 to the atmosphere, but the deeper-layer production is found to be more important for the

  16. Air-snowpack exchange of bromine, ozone and mercury in the springtime Arctic simulated by the 1-D model PHANTAS – Part 1: In-snow bromine activation and its impact on ozone

    Directory of Open Access Journals (Sweden)

    K. Toyota

    2013-08-01

    Full Text Available To provide a theoretical framework towards better understanding of ozone depletion events (ODEs and atmospheric mercury depletion events (AMDEs in the polar boundary layer, we have developed a one-dimensional model that simulates multiphase chemistry and transport of trace constituents from porous snowpack and through the atmospheric boundary layer (ABL as a unified system. In this paper, we describe a general configuration of the model and the results of simulations related to reactive bromine release from the snowpack and ODEs during the Arctic spring. The model employs a chemical mechanism adapted from the one previously used for the simulation of multiphase halogen chemistry involving deliquesced sea-salt aerosols in the marine boundary layer. A common set of aqueous-phase reactions describe chemistry both in the liquid-like (or brine layer on the grain surface of the snowpack and in "haze" aerosols mainly composed of sulfate in the atmosphere. The process of highly soluble/reactive trace gases, whether entering the snowpack from the atmosphere or formed via gas-phase chemistry in the snowpack interstitial air (SIA, is simulated by the uptake on brine-covered snow grains and subsequent reactions in the aqueous phase while being traveled vertically within the SIA. A "bromine explosion", by which, in a conventional definition, HOBr formed in the ambient air is deposited and then converted heterogeneously to Br2, is a dominant process of reactive bromine formation in the top 1 mm (or less layer of the snowpack. Deeper in the snowpack, HOBr formed within the SIA leads to an in-snow bromine explosion, but a significant fraction of Br2 is also produced via aqueous radical chemistry in the brine on the surface of the snow grains. These top- and deeper-layer productions of Br2 both contribute to the Br2 release into the atmosphere, but the deeper-layer production is found to be more important for the net outflux of reactive bromine. Although ozone

  17. Characterization of thermally evaporated lead iodide films aimed for the detection of X-rays

    International Nuclear Information System (INIS)

    Some semiconductor materials such as lead iodide (PbI2) have applications in the detection of ionizing radiation at room temperature using the direct detection method. In this work we investigate lead iodide films deposited by thermal evaporation. The morphology, structure, and electric properties were investigated as a function of deposition height, i.e. the distance between evaporation-boat and substrates. The results show a morphology of vertical leaves and X-ray diffraction shows just one preferential orientation along the direction 110. Energy dispersive spectroscopy reveals that the films are not stoichiometric, with excess iodine atoms. Electrical resistivity of about 108 Ω cm was measured. This is smaller than for the bulk due to structural defects. The values of activation energy for electric transport increase from 0.52 up to 1.1 eV with decreasing deposition height, what indicates that the best film is the one deposited at the shortest distance. Exposure under X-ray mammographic energy shows a linear behavior up to 500 mR. No variation in sensibility was observed between 22 and 30 kVp.

  18. Sodium Iodide Symporter for Nuclear Molecular Imaging and Gene Therapy: From Bedside to Bench and Back

    Directory of Open Access Journals (Sweden)

    Byeong-Cheol Ahn

    2012-01-01

    Full Text Available Molecular imaging, defined as the visual representation, characterization and quantification of biological processes at the cellular and subcellular levels within intact living organisms, can be obtained by various imaging technologies, including nuclear imaging methods. Imaging of normal thyroid tissue and differentiated thyroid cancer, and treatment of thyroid cancer with radioiodine rely on the expression of the sodium iodide symporter (NIS in these cells. NIS is an intrinsic membrane protein with 13 transmembrane domains and it takes up iodide into the cytosol from the extracellular fluid. By transferring NIS function to various cells via gene transfer, the cells can be visualized with gamma or positron emitting radioisotopes such as Tc-99m, I-123, I-131, I-124 and F-18 tetrafluoroborate, which are accumulated by NIS. They can also be treated with beta- or alpha-emitting radionuclides, such as I-131, Re-186, Re-188 and At-211, which are also accumulated by NIS. This article demonstrates the diagnostic and therapeutic applications of NIS as a radionuclide-based reporter gene for trafficking cells and a therapeutic gene for treating cancers.

  19. The effect of potassium iodide on the production of acid phosphatase by Sporothrix schenckii

    Directory of Open Access Journals (Sweden)

    P. S. Grover

    2003-06-01

    Full Text Available The present study was undertaken to find out the in vitro effect of potassium iodide (KI on the production of acid phosphatase by fully characterized strain of S.schenckii isolated from a patient of Cutaneous Sporotrichosis. The enzyme acid phosphatase was estimated during the 3 phases of growth of S.schenckii, without and with three concentrations of KI incorporated in the culture medium. In the control and in the test proper, with various concentrations of KI, no adverse effect of KI was observed on the production of acid phosphatase in early and mid log phase of fungal growth. Whereas in the exponential phase in test proper, there was a statistical significant decrease in the enzyme production with 0.8% and 3.2% of KI. The low activity at 0.8% and 3.2% KI indicates that KI has inhibitory effect on the growth of S.schenckii and has led to decrease in the activity of the enzyme. (Med J Indones 2003; 12: 65-8 Keywords: S.schenckii, acid phosphatase, potassium iodide

  20. Iodine in raw and pasteurized milk of dairy cows fed different amounts of potassium iodide.

    Science.gov (United States)

    Norouzian, M A

    2011-02-01

    Relation between iodine (I) intake by lactating Holstein cows and iodine concentrations in raw and pasteurized milk were investigated. Four treatment groups with eight cows assigned to each treatment were fed a basal diet containing 0.534 mg I/kg alone or supplemented with potassium iodide at 2.5, 5 or 7.5 mg/kg in 7-week period. Iodine concentrations in raw milk increased with each increase in dietary I from 162.2 ng/ml for basal diet to 534.5, 559.8 and 607.5 ng/ml when 2.5, 5 and 7.5 mg/kg was fed as potassium iodide (P iodine concentration. Iodine supplementation had no significant effect on thyroidal hormones. high-temperature short-time (HTST) pasteurization process reduced I concentration. The mean iodine content found in the milk prior to heating processing was 466.0 ± 205.0 ng/ml, whereas for the processed milk this level was 349.5 ± 172.8 ng/ml. It was concluded that iodine supplementation above of NRC recommendation (0.5 mg/kg diet DM) resulted in significant increases in iodine concentrations in milk, although the effect of heating in HTST pasteurization process on iodine concentration was not negligible.

  1. Sodium iodide symporter (NIS) in extrathyroidal malignancies: focus on breast and urological cancer

    International Nuclear Information System (INIS)

    Expression and function of sodium iodide symporter (NIS) is requisite for efficient iodide transport in thyrocytes, and its presence in cancer cells allows the use of radioiodine as a diagnostic and therapeutic tool in thyroid neoplasia. Discovery of NIS expression in extrathyroidal tissues, including transformed cells, has opened a novel field of research regarding NIS-expressing extrathyroidal neoplasia. Indeed, expression of NIS may be used as a biomarker for diagnostic, prognostic, and therapeutic purposes. Moreover, stimulation of endogenous NIS expression may permit the radioiodine treatment of extrathyroidal lesions by concentrating this radioisotope. This review describes recent findings in NIS research in extrathyroidal malignancies, focusing on breast and urological cancer, emphasizing the most relevant developments that may have clinical impact. Given the recent progress in the study of NIS regulation as molecular basis for new therapeutic approaches in extrathyroidal cancers, particular attention is given to studies regarding the relationship between NIS and clinical-pathological aspects of the tumors and the regulation of NIS expression in the experimental models

  2. Chitosan finishing nonwoven textiles loaded with silver and iodide for antibacterial wound dressing applications.

    Science.gov (United States)

    Aubert-Viard, François; Martin, Adeline; Chai, Feng; Neut, Christel; Tabary, Nicolas; Martel, Bernard; Blanchemain, Nicolas

    2015-02-01

    Polyethylene terephtalate (PET) and Polypropylene (PP) textiles are widely used in biomedical application such as wound dressings and implants. The aim of this work was to develop an antibacterial chitosan (CHT) coating activated by silver or by iodine. Chitosan was immobilized onto PET and PP supports using citric acid (CTR) as a crosslinking agent through a pad-dry-cure textile finishing process. Interestingly, depending on the CHT/CTR molar ratio, two different systems were obtained: rich in cationic ammonium groups when the CTR concentration was 1%w/v, and rich in anionic carboxylate groups when the CTR concentration was 10%w/v. As a consequence, such samples could be selectively loaded with iodine and silver nitrate, respectively.Both types of coatings were analyzed using SEM and FTIR, their sorption capacities were evaluated toward iodide/iodate anions (I(-)/IO3(-)) and the silver cations (Ag(+)) were evaluated using elemental analysis. Finally, in vitro evaluations were carried out to evaluate the cytocompatibility on the epithelial cell line. The silver loaded textile reported a stronger antibacterial effect against E.coli (5 log10 reduction) than toward S. aureus (3 log10) while the antibacterial effect of the iodide loaded textiles was limited to 1 log10 to 2 log10 on both strains. PMID:25730424

  3. Characterization of thermally evaporated lead iodide films aimed for the detection of X-rays

    Energy Technology Data Exchange (ETDEWEB)

    Caldeira Filho, A.M. [Departamento de Fisica, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo - USP, Avenida Bandeirantes 3900, 14040-901, Ribeirao Preto-SP (Brazil); Mulato, M., E-mail: mmulato@ffclrp.usp.b [Departamento de Fisica, Faculdade de Filosofia, Ciencias e Letras de Ribeirao Preto, Universidade de Sao Paulo - USP, Avenida Bandeirantes 3900, 14040-901, Ribeirao Preto-SP (Brazil)

    2011-04-21

    Some semiconductor materials such as lead iodide (PbI{sub 2}) have applications in the detection of ionizing radiation at room temperature using the direct detection method. In this work we investigate lead iodide films deposited by thermal evaporation. The morphology, structure, and electric properties were investigated as a function of deposition height, i.e. the distance between evaporation-boat and substrates. The results show a morphology of vertical leaves and X-ray diffraction shows just one preferential orientation along the direction 110. Energy dispersive spectroscopy reveals that the films are not stoichiometric, with excess iodine atoms. Electrical resistivity of about 10{sup 8} {Omega} cm was measured. This is smaller than for the bulk due to structural defects. The values of activation energy for electric transport increase from 0.52 up to 1.1 eV with decreasing deposition height, what indicates that the best film is the one deposited at the shortest distance. Exposure under X-ray mammographic energy shows a linear behavior up to 500 mR. No variation in sensibility was observed between 22 and 30 kVp.

  4. Observation of crystallization and characterizations on thiourea cadmium iodide: A semi-organic optical material

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Preeti; Hasmuddin, Mohd. [Crystal Growth and XRD Lab, Department of Physics, Jamia Millia Islamia, New Delhi 110025 (India); Abdullah, M.M. [Crystal Growth and XRD Lab, Department of Physics, Jamia Millia Islamia, New Delhi 110025 (India); Promising Centre for Sensors and Electronic Devices (PCSED), Department of Physics, Faculty of Sciences and Arts, Najran University, P.O. Box 1988, Najran 11001 (Saudi Arabia); Shkir, Mohd. [Crystal Growth and XRD Lab, Department of Physics, Jamia Millia Islamia, New Delhi 110025 (India) and Department of Physics, ARSD College, University of Delhi, New Delhi 110021 (India); Wahab, M.A., E-mail: aries.pre84@gmail.com [Crystal Growth and XRD Lab, Department of Physics, Jamia Millia Islamia, New Delhi 110025 (India)

    2013-10-15

    Graphical abstract: - Highlights: • Thiourea cadmium iodide (TCI) was grown by slow evaporation solution technique. • Morphology and growth rate of the grown compound are determined with the help of inverted microscope. • Optical band gap has been determined. • Microstructure analysis has been reported. • Electrical study has been reported and discussed. - Abstract: In this work, the single crystals of thiourea cadmium iodide were grown by slow evaporation solution technique in two different ratios 2:1 and 1:1. During the formation of their single crystals the morphological features and its live growth process were recorded with the help of inverted microscope. Structural studies of the grown crystals have been carried out by powder X-ray diffraction to confirm the crystal system and vibrational modes by Raman spectroscopy. The optical energy band gaps were investigated through UV–vis spectroscopy study. The surface morphology of the grown single crystals was analyzed by using Scanning Electron Microscope and thermal analysis was carried out by using thermogravimetric analysis. The electrical properties were also studied as a function of frequency and the obtained results are discussed.

  5. Analysis of perchlorate, thiocyanate, nitrate and iodide in human amniotic fluid using ion chromatography and electrospray tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Blount, Benjamin C. [Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA 30341 (United States)]. E-mail: bblount@cdc.gov; Valentin-Blasini, Liza [Division of Laboratory Sciences, National Center for Environmental Health, Centers for Disease Control and Prevention, Atlanta, GA 30341 (United States)

    2006-05-10

    Because of health concerns surrounding in utero exposure to perchlorate, we developed a sensitive and selective method for quantifying iodide, as well as perchlorate and other sodium-iodide symporter (NIS) inhibitors in human amniotic fluid using ion chromatography coupled with electrospray ionization tandem mass spectrometry. Iodide and NIS inhibitors were quantified using a stable isotope-labeled internal standards (Cl{sup 18}O{sub 4} {sup -}, S{sup 13}CN{sup -} and {sup 15}NO{sub 3} {sup -} with excellent assay accuracy of 100%, 98%, 99%, 95% for perchlorate, thiocyanate, nitrate and iodide, respectively, in triplicate analysis of spiked amniotic fluid sample). Excellent analytical precision (<5.2% RSD for all analytes) was found when amniotic fluid quality control pools were repetitively analyzed for iodide and NIS-inhibitors. Selective chromatography and tandem mass spectrometry reduced the need for sample cleanup, resulting in a rugged and rapid method capable of routinely analyzing 75 samples/day. Analytical response was linear across the physiologically relevant concentration range for the analytes. Analysis of a set of 48 amniotic fluid samples identified the range and median levels for perchlorate (0.057-0.71, 0.18 {mu}g/L), thiocyanate (<10-5860, 89 {mu}g/L), nitrate (650-8900, 1620 {mu}g/L) and iodide (1.7-170, 8.1 {mu}g/L). This selective, sensitive, and rapid method will help assess exposure of the developing fetus to low levels of NIS-inhibitors and their potential to inhibit thyroid function.

  6. Brominated flame retardants and organochlorine compounds in duplicate diet samples from a Portuguese academic community.

    Science.gov (United States)

    Coelho, Sónia D; Sousa, Ana C A; Isobe, Tomohiko; Kunisue, Tatsuya; Nogueira, António J A; Tanabe, Shinsuke

    2016-10-01

    Concentrations of persistent organic pollutants (POPs), including polybrominated diphenyl ethers (PBDEs), hexabromocyclododecanes (HBCDDs), polychlorinated biphenyls (PCBs), hexachlorocyclohexane isomers (HCHs), hexachlorobenzene (HCB), chlordane compounds (CHLs) and dichlorodiphenyltrichloroethane and its metabolites (DDTs), were measured in duplicate diet samples from 21 volunteers at a Portuguese academic community (University of Aveiro). Overall, the levels of the target compounds were low, with detection frequencies varying widely depending on the compounds and with brominated flame retardants (BFRs) registering the lowest detection frequencies. Among PCB congeners, nondioxin-like PCBs were predominant and detected in the majority of the samples. Organochlorine pesticides were also detected in the majority of the samples, with 100% detection for DDTs and HCHs. Estimated daily intakes (EDIs) were calculated using lower and upper bound estimations, and in both cases values were far below the currently established tolerable daily intakes for PCBs and OCs and the reference doses for PBDEs and HBCDDs. PMID:27367176

  7. Kinetics and mechanism of the oxidation of some -hydroxy acids by hexamethylenetetramine-bromine

    Indian Academy of Sciences (India)

    Dimple Garg; Seema Kothari

    2004-11-01

    The oxidation of lactic acid, mandelic acid and ten monosubstituted mandelic acids by hexamethylenetetramine-bromine (HABR) in glacial acetic acid, leads to the formation of the corresponding oxoacid. The reaction is first order with respect to each of the hydroxy acids and HABR. It is proposed that HABR itself is the reactive oxidizing species. The oxidation of -deuteriomandelic acid exhibits the presence of a substantial kinetic isotope effect (/ = 5.91 at 298 K). The rates of oxidation of the substituted mandelic acids show excellent correlation with Brown’s + values. The reaction constants are negative. The oxidation exhibits an extensive cross conjugation between the electron-donating substituent and the reaction centre in the transition state. A mechanism involving transfer of a hydride ion from the acid to the oxidant is postulated.

  8. Short-lived brominated hydrocarbons – observations in the source regions and the tropical tropopause layer

    Directory of Open Access Journals (Sweden)

    S. Brinckmann

    2012-02-01

    Full Text Available We conducted measurements of the five important short-lived organic bromine species in the marine boundary layer (MBL. Measurements were made in the Northern Hemisphere mid-latitudes (Sylt Island, North Sea in June 2009 and in the tropical Western Pacific during the TransBrom ship campaign in October 2009. For the one-week time series on Sylt Island, mean mixing ratios of CHBr3, CH2Br2, CHBr2Cl and CH2BrCl were 2.0, 1.1, 0.2, 0.1 ppt, respectively. We found maxima of 5.8 and 1.6 ppt for the two main components CHBr3 and CH2Br2. Along the cruise track in the Western Pacific (between 41° N and 13° S we measured mean mixing ratios of 0.9, 0.9, 0.2, 0.1 and 0.1 ppt for CHBr3, CH2Br2, CHBrCl2, CHBr2Cl and CH2BrCl. Air samples with coastal influence showed considerably higher mixing ratios than the samples with open ocean origin. Correlation analyses of the two data sets yielded strong linear relationships between the mixing ratios of four of the five species (except for CH2BrCl. Using a combined data set from the two campaigns and a comparison with the results from two former studies, rough estimates of the molar emission ratios between the correlated substances were: 9/1/0.35/0.35 for CHBr3/CH2Br2/CHBrCl2/CHBr2Cl. Additional measurements were made in the tropical tropopause layer (TTL above Teresina (Brazil, 5° S in June 2008, using balloon-borne cryogenic whole air sampling technique. Near the level of zero clear-sky net radiative heating (LZRH at 14.8 km about 2.25 ppt organic bromine was bound to the five short-lived species, making up 13% of total organic bromine (17.82 ppt. CH2Br2 (1.45 ppt and CHBr3 (0.56 ppt accounted for 90% of the budget of short-lived compounds in that region. Near the

  9. Responses of marine unicellular algae to brominated organic compounds in six growth media

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, G.E.; Yoder, M.J.; McLaughlin, L.L.; Lores, E.M.

    1987-12-01

    Marine unicellular algae, Skeletonema costatum, Thalassiosira pseudonana, and Chlorella sp. were exposed to the industrial brominated compounds tetrabromobisphenol A, decabromobiphenyloxide (DBBO), hexabromocyclododecane (HBCD), pentabromomethylbenzene (PBMB), pentabromoethylbenzene (PBEB), and the herbicide bromoxynil (BROM), in six algal growth media. High concentrations of DBBO (1 mg liter-1), PBMB (1 mg liter-1), and PBEB (0.5 mg liter-1) reduced growth by less than 50%. EC50s of the other compounds varied with growth medium, with high EC50/low EC50 ratios between 1.3 and 9.9. Lowest EC50s, 9.3 to 12.0 micrograms liter-1, were obtained with S. costatum and HBCD. It is concluded that responses to toxicants in different media are the results of interactions among algae, growth medium, toxicant, and solvent carrier.

  10. Mercury oxidation from bromine chemistry in the free troposphere over the southeastern US

    Science.gov (United States)

    Coburn, Sean; Dix, Barbara; Edgerton, Eric; Holmes, Christopher D.; Kinnison, Douglas; Liang, Qing; ter Schure, Arnout; Wang, Siyuan; Volkamer, Rainer

    2016-03-01

    The elevated deposition of atmospheric mercury over the southeastern United States is currently not well understood. Here we measure partial columns and vertical profiles of bromine monoxide (BrO) radicals, a key component of mercury oxidation chemistry, to better understand the processes and altitudes at which mercury is being oxidized in the atmosphere. We use data from a ground-based MAX-DOAS instrument located at a coastal site ˜ 1 km from the Gulf of Mexico in Gulf Breeze, FL, where we had previously detected tropospheric BrO (Coburn et al., 2011). Our profile retrieval assimilates information about stratospheric BrO from the WACCM chemical transport model (CTM), and uses only measurements at moderately low solar zenith angles (SZAs) to estimate the BrO slant column density contained in the reference spectrum (SCDRef). The approach has 2.6 degrees of freedom, and avoids spectroscopic complications that arise at high SZA; knowledge about SCDRef further helps to maximize sensitivity in the free troposphere (FT). A cloud-free case study day with low aerosol load (9 April 2010) provided optimal conditions for distinguishing marine boundary layer (MBL: 0-1 km) and free-tropospheric (FT: 1-15 km) BrO from the ground. The average daytime tropospheric BrO vertical column density (VCD) of ˜ 2.3 × 1013 molec cm-2 (SZA < 70°) is consistent with our earlier reports on other days. The vertical profile locates essentially all tropospheric BrO above 4 km, and shows no evidence for BrO inside the MBL (detection limit < 0.5 pptv). BrO increases to ˜ 3.5 pptv at 10-15 km altitude, consistent with recent aircraft observations. Our case study day is consistent with recent aircraft studies, in that the oxidation of gaseous elemental mercury (GEM) by bromine radicals to form gaseous oxidized mercury (GOM) is the dominant pathway for GEM oxidation throughout the troposphere above Gulf Breeze. The column integral oxidation rates are about 3.6 × 105 molec cm-2 s-1 for bromine

  11. Bioactive brominated diterpenes from the marine red alga Jania Rubens (L.) Lamx.

    Science.gov (United States)

    Awad, Nagwa E

    2004-04-01

    Seven brominated diterpenes of the parguerene and isoparguerene series were isolated for the first time from the red alga Jania rubens (L.) Lamx., collected from the Red Sea coast at Hurghada, Egypt. The diterpenes were identified as isoparguerol (1), isoparguerol-16-acetate (2), isoparguerol-7,16-diacetate (3), parguerol-16-acetate (4), parguerol-7,16-diacetate (5), deoxyparguerol (6) and deoxyparguerol-7-acetate (7). The isolated diterpenes had a marked antitumour activity. Isoparguerol derivatives were slightly more effective than parguerol derivatives. Moreover, the data implied that the cytotoxicity of these compounds were dependent on the number of acetoxy groups. Also, anthelmintic activities of the isolated compounds on earthworms (Allolobophora caliginosa) were studied. PMID:15162360

  12. Thinning of CIGS solar cells: Part I: Chemical processing in acidic bromine solutions

    Energy Technology Data Exchange (ETDEWEB)

    Bouttemy, M.; Tran-Van, P. [Institut Lavoisier de Versailles (ILV-UMR 8180 CNRS/UVSQ), 45 av. des Etats Unis, 78035 Versailles (France); Gerard, I., E-mail: gerard@chimie.uvsq.fr [Institut Lavoisier de Versailles (ILV-UMR 8180 CNRS/UVSQ), 45 av. des Etats Unis, 78035 Versailles (France); Hildebrandt, T.; Causier, A. [Institut Lavoisier de Versailles (ILV-UMR 8180 CNRS/UVSQ), 45 av. des Etats Unis, 78035 Versailles (France); Pelouard, J.L.; Dagher, G. [Laboratoire de Photonique et de Nanostructures (LPN-CNRS), route de Nozay 91460 Marcoussis (France); Jehl, Z.; Naghavi, N. [Institut de Recherche et Developpement sur l' Energie Photovoltaique (IRDEP -UMR 7174 CNRS/EDF/Chimie-ParisTech), 6 quai Watier, 78401 Chatou (France); Voorwinden, G.; Dimmler, B. [Wuerth Elektronik Research GmbH, Industriestr. 4, 70565 Stuttgart (Germany); Powalla, M. [Zentrum fuer Sonnenenergie- und Wasserstoff-Forschung (ZSW), Industriestr. 6, 70565 Stuttgart (Germany); Guillemoles, J.F. [Institut de Recherche et Developpement sur l' Energie Photovoltaique (IRDEP -UMR 7174 CNRS/EDF/Chimie-ParisTech), 6 quai Watier, 78401 Chatou (France); Lincot, D. [Laboratoire de Photonique et de Nanostructures (LPN-CNRS), route de Nozay 91460 Marcoussis (France); Etcheberry, A. [Institut Lavoisier de Versailles (ILV-UMR 8180 CNRS/UVSQ), 45 av. des Etats Unis, 78035 Versailles (France)

    2011-08-31

    CIGSe absorber was etched in HBr/Br{sub 2}/H{sub 2}O to prepare defined thicknesses of CIGSe between 2.7 and 0.5 {mu}m. We established a reproducible method of reducing the absorber thickness via chemical etching. We determine the dissolution kinetics rate of CIGSe using trace analysis by graphite furnace atomic absorption spectrometry of Ga and Cu. The roughness of the etching surface decreases during the first 500 nm of the etching to a steady state value of the root-mean-square roughness near 50 nm. X-ray photoelectron spectroscopy analyses demonstrate an etching process occurring with a constant chemical composition of the treated surface acidic bromine solutions provide a controlled chemical thinning process resulting in an almost flat surface and a very low superficial Se{sup 0} enrichment.

  13. Surface-confined 2D polymerization of a brominated copper-tetraphenylporphyrin on Au(111)

    CERN Document Server

    Smykalla, Lars; Korb, Marcus; Lang, Heinrich; Hietschold, Michael

    2015-01-01

    A coupling-limited approach for the Ullmann reaction-like on-surface synthesis of a two-dimensional covalent organic network starting from a halogenated metallo-porphyrin is demonstrated. Copper-octabromo-tetraphenylporphyrin molecules can diffuse and self-assemble when adsorbed on the inert Au(111) surface. Splitting-off of bromine atoms bonded at the macrocyclic core of the porphyrin starts at room temperature after the deposition and is monitored by X-ray photoelectron spectroscopy for different annealing steps. Direct coupling between the reactive carbon sites of the molecules is, however, hindered by the molecular shape. This leads initially to an ordered non-covalently interconnected supramolecular structure. Further heating to 300{\\deg}C and an additional hydrogen dissociation step is required to link the molecular macrocycles via a phenyl group and form large ordered polymeric networks. This approach leads to a close-packed covalently bonded network of overall good quality. The structures are characte...

  14. Replacement of monochromator and proportional gas counter by mercuric iodide detector in X-ray powder diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Nissenbaum, J.; Levi, A.; Burger, A.; Schieber, M. (Hebrew Univ., Jerusalem (Israel). School of Applied Science and Technology)

    1983-02-01

    Low resolution and therefore low-cost mercuric iodide detectors have successfully been applied to replace the combination of a graphite monochromator and a proportional gas radiation counter used in X-ray diffractometers. The mercuric iodide detector requires a lower DC bias of only 200 V rather than the 1500 V bias needed for the proportional gas counter. The much better stopping power of HgI/sub 2/ allows higher counting efficiency and therefore a better signal-to-noise ratio. Results are shown for X-ray powder diffractions of polycrystalline cubic silicon and tetragonal HgI/sub 2/.

  15. UTILIZATION OF BROMINATION REACTION FOR THE SPECTROPHOTOMETRIC ASSAY OF DOMPERIDONE IN PHARMACEUTICALS

    Directory of Open Access Journals (Sweden)

    O. ZENITA DEVI

    2011-03-01

    Full Text Available Three simple and sensitive spectrophotometric methods are described for the determination of domperidone (DOM in bulk drug and in dosage forms using bromate-bromide mixture as brominating agent in acid medium and three dyes, meta-cresol purple (MCP, amaranth (AMR and erioglaucine (EGC. The methods involve the addition of a known excess of bromate-bromide mixture to an acidified solution of DOM followed by the determination of the residual bromine by reacting with a fixed amount of either MCP dye and measuring the absorbance at 530 nm (method A or AMR dye and measuring the absorbance at 520 nm (method B or EGC dye and measuring the absorbance at 630 nm (method C. Beer’s law is obeyed over the concentration ranges, 0.63–10.0, 0.25-4.0 and 0.13-2.0 µg mL-1 for method A, B and C, respectively. The ap¬parent molar absorptivities are calculated to be 3.751x104, 6.604x104 and 1.987x105 L mol-1cm-1 for method A, B and C, respectively, and the corresponding sandell sensitivity values are 0.011, 0.006 and 0.002 μg cm-2. The limit of detection and the limit of quantification are also reported for all the three methods. No interference was observed from common additives found in pharmaceutical preparations. Statistical comparisons of the results with those of the reference method showed excellent agreement, and indicated no significant difference in accuracy and precision. The accuracy and reliability of the methods were further ascertained by performing recovery tests via standardaddition technique.

  16. Associations between brominated flame retardants in house dust and hormone levels in men

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Paula I. [Department of Environmental Health Sciences, University of Michigan, 1415 Washington Heights, Ann Arbor, MI 48109 (United States); Stapleton, Heather M. [Nicholas School of the Environment, Box 90328, Duke University, Durham, NC 27708 (United States); Mukherjee, Bhramar [Department of Biostatistics, University of Michigan, 1415 Washington Heights, Ann Arbor, MI 48109 (United States); Hauser, Russ [Department of Environmental Health, Harvard School of Public Health, 677 Huntington Ave., Boston, MA 02115 (United States); Meeker, John D., E-mail: meekerj@umich.edu [Department of Environmental Health Sciences, University of Michigan, 1415 Washington Heights, Ann Arbor, MI 48109 (United States)

    2013-02-15

    Brominated flame retardants (BFRs) are used in the manufacture of a variety of materials and consumer products in order to meet fire safety standards. BFRs may persist in the environment and have been detected in wildlife, humans and indoor dust and air. Some BFRs have demonstrated endocrine and reproductive effects in animals, but human studies are limited. In this exploratory study, we measured serum hormone levels and flame retardant concentrations [31 polybrominated diphenyl ether (PBDE) congeners and 6 alternate flame retardants] in house dust from men recruited through a US infertility clinic. PBDE congeners in dust were grouped by commercial mixtures (i.e. penta-, octa- and deca-BDE). In multivariable linear regression models adjusted by age and body mass index (BMI), significant positive associations were found between house dust concentrations of pentaBDEs and serum levels of free T4, total T3, estradiol, and sex hormone binding globulin (SHBG), along with an inverse association with follicle stimulating hormone (FSH). There were also positive associations of octaBDE concentrations with serum free T4, thyroid stimulating hormone (TSH), luteinizing hormone (LH) and testosterone and an inverse association of decaBDE concentrations with testosterone. Hexabromocyclododecane (HBCD) was associated with decreased SHBG and increased free androgen index. Dust concentrations of bis-tribromophenoxyethane (BTBPE) and tetrabromo-diethylhexylphthalate (TBPH) were positively associated with total T3. These findings are consistent with our previous report of associations between PBDEs (BDE 47, 99 and 100) in house dust and hormone levels in men, and further suggest that exposure to contaminants in indoor dust may be leading to endocrine disruption in men. - Highlights: ► Brominated flame retardants (BFRs) including PBDEs and alternates were measured. ► Exposure to BFRs is characterized from concentrations in participant vacuum bag dust. ► Exposure to PBDEs and

  17. Determination of chlorine, fluorine, bromine, and iodine in coals with ICP-MS and IC

    Energy Technology Data Exchange (ETDEWEB)

    Bettinelli, M.; Spezia, S.; Minoia, C.; Ronchi, A. [Salvatore Maugeri Foundation, Pavia (Italy)

    2002-07-01

    The combustion process releases many organic and inorganic pollutants into the atmosphere, both in gaseous and solid form. During coal combustion in thermal power plants without pollution control equipment, chlorine, fluorine, bromine, and iodine present in coals are mainly volatilized as gaseous compounds. Limiting pollutant emissions is a precise requirement of the Italian legislation that fixes (in the case of power plants) 100 mg/Nm{sup 3} as the limit value for chlorine, and 5 mg/Nm{sup 3} for fluorine and bromine (expressed as hydrofluoric and hydrobromic acid respectively). No limit for iodine emissions has been established. From this point of view and in order to maintain control of emissions from combustion plants, it is important to monitor the concentration of halogens in fuels. Unfortunately, in literature there are very few data published with regard to the amount of halogens in fossil fuels, which emphasizes the analytical difficulties with regard to the determination of these analytes. In the present paper a, pyrohydrolysis of the sample at 1100{degree}C, followed by the absorption of volatilized compounds in Na{sub 2}CO{sub 3}/NaHCO{sub 3} solution and the final instrumental analysis of Cl, Br, and F with ion chromatography (IC) and Br and I with inductively coupled plasma mass spectrometry (ICP-MS) has been adopted. The accuracy of the method, evaluated by analyzing some certified reference materials, was better than 95% for all analytes and the detection limits adequate to the analytical requirements (0.1 mg/kg for Br and I, 1 mg/kg for F, and 10 mg/kg for C1).

  18. Associations between brominated flame retardants in house dust and hormone levels in men

    International Nuclear Information System (INIS)

    Brominated flame retardants (BFRs) are used in the manufacture of a variety of materials and consumer products in order to meet fire safety standards. BFRs may persist in the environment and have been detected in wildlife, humans and indoor dust and air. Some BFRs have demonstrated endocrine and reproductive effects in animals, but human studies are limited. In this exploratory study, we measured serum hormone levels and flame retardant concentrations [31 polybrominated diphenyl ether (PBDE) congeners and 6 alternate flame retardants] in house dust from men recruited through a US infertility clinic. PBDE congeners in dust were grouped by commercial mixtures (i.e. penta-, octa- and deca-BDE). In multivariable linear regression models adjusted by age and body mass index (BMI), significant positive associations were found between house dust concentrations of pentaBDEs and serum levels of free T4, total T3, estradiol, and sex hormone binding globulin (SHBG), along with an inverse association with follicle stimulating hormone (FSH). There were also positive associations of octaBDE concentrations with serum free T4, thyroid stimulating hormone (TSH), luteinizing hormone (LH) and testosterone and an inverse association of decaBDE concentrations with testosterone. Hexabromocyclododecane (HBCD) was associated with decreased SHBG and increased free androgen index. Dust concentrations of bis-tribromophenoxyethane (BTBPE) and tetrabromo-diethylhexylphthalate (TBPH) were positively associated with total T3. These findings are consistent with our previous report of associations between PBDEs (BDE 47, 99 and 100) in house dust and hormone levels in men, and further suggest that exposure to contaminants in indoor dust may be leading to endocrine disruption in men. - Highlights: ► Brominated flame retardants (BFRs) including PBDEs and alternates were measured. ► Exposure to BFRs is characterized from concentrations in participant vacuum bag dust. ► Exposure to PBDEs and

  19. Scientific Opinion on Emerging and Novel Brominated Flame Retardants (BFRs in Food

    Directory of Open Access Journals (Sweden)

    EFSA Panel on Contaminants in the Food Chain (CONTAM

    2012-10-01

    Full Text Available EFSA was asked to deliver a scientific opinion on brominated flame retardants (BFRs other than PBDEs, PBBs, HBCDDs, TBBPA and brominated phenols and their derivatives. The BFRs that are the subject of the current opinion, were classified in groups termed ‘emerging’ and ‘novel’ BFRs. Information on 17 emerging and 10 novel BFRs was collected. The information varied widely for these BFRs. There is a lack of experimental data on physico-chemical characteristics, stability/reactivity and current use and production volume of all the emerging and novel BFRs. Due to the very limited information on occurrence, exposure and toxicity, the CONTAM Panel could not perform a risk characterisation for any of the BFRs considered. Instead, an attempt was made to identify those BFRs that could be a potential health concern and should be considered first for future investigations. For this purpose the Panel first evaluated the available experimental data on occurrence in food, behaviour in the environment and toxicity. Secondly, a modelling exercise was performed focussing on the potential of the emerging and novel BFRs for persistence in the environment and for their possible bioaccumulation potential. There is convincing evidence that tris(2,3-dibromopropyl phosphate (TDBPP and dibromoneopentyl glycol (DBNPG are genotoxic and carcinogenic, warranting further surveillance of their occurrence in the environment and in food. Based on the limited experimental data on environmental behaviour, 1,2-bis(2,4,6-tribromophenoxyethane (BTBPE and hexabromobenzene (HBB were identified as compounds that could raise a concern for bioaccumulation. For the modelling exercise, the CONTAM Panel selected two environmental characteristics, overall persistence and potential for bioaccumulation, as being most relevant to provide insight into the possibility that emerging or novel BFRs might accumulate in the food chain, and thus might appear in food intended for human

  20. Meteorological controls on the vertical distribution of bromine monoxide in the lower troposphere

    Directory of Open Access Journals (Sweden)

    P. K. Peterson

    2014-09-01

    Full Text Available Multiple axis differential absorption spectroscopy (MAX-DOAS measurements of bromine monoxide (BrO probed the vertical structure of halogen activation events during March–May 2012 at Barrow, Alaska. An analysis of the BrO averaging kernels and degrees of freedom obtained by optimal-estimation-based inversions from raw MAX-DOAS measurements reveals the information is best represented by reducing the retrieved BrO profile to two quantities, the integrated column from the surface through 200 m (VCD200 m, and the lower tropospheric vertical column density (LT-VCD which represents the integrated column of BrO from the surface through 2 km. The percentage of lower-tropospheric BrO in the lowest 200 m was found to be highly variable ranging from shallow layer events, where BrO is present primarily in the lowest 200 m to distributed column events where BrO is observed at higher altitudes. The highest observed LT-VCD events occurred when BrO was distributed throughout the lower troposphere, rather than concentrated near the surface. Atmospheric stability in the lowest 200 m influenced the percentage of LT-VCD that is in the lowest 200 m, with inverted temperature structures having a first-to-third quartile range (Q1–Q3 of VCD200 m/LT-VCD from 15–39% while near neutral temperature structures had a Q1–Q3 range of 7–13%. Data from this campaign show no clear influence of wind speed on either lower-tropospheric bromine activation (LT-VCD or the vertical distribution of BrO, while examination of seasonal trends and the temperature dependence of the vertical distribution supported the conclusion that the atmospheric stability affects the vertical distribution of BrO.

  1. A reversible fluorescent INHIBIT logic gate for determination of silver and iodide based on the use of graphene oxide and a silver–selective probe DNA

    International Nuclear Information System (INIS)

    We describe a reversible fluorescent DNA–based INHIBIT logic gate for the determination of silver(I) and iodide ions using graphene oxide (GO) as a signal transducer and Ag(I) and iodide as mechanical activators. The basic performance, optimized conditions, sensitivity and selectivity of the logic gate were investigated and revealed that the method is highly sensitive and selective over potentially interfering ions. The limits of detection for Ag(I) and iodide are 10 nM and 50 nM, respectively. This logic gate was successfully applied to the determination of Ag(I) and iodide in (spiked) tap water and river water. It was also used for the determination of iodide in human urine samples with satisfactory results. Compared to other methods, this INHIBIT logic gate is simple in design and has small background interference. (author)

  2. Synthesis of 1-Bromo-3-methoxy-4-propoxy-5-iodobenzene-A Novel Efficient Process for the Synthesis of Brominated Aromatic Compound

    Institute of Scientific and Technical Information of China (English)

    Hong Xin SHI; Hui LIN; Gérard MANDVILLE

    2004-01-01

    The reaction of aromatic carboxylic acid with oxalyl chloride gives rise to the corres- ponding acid chloride which without purification is treated with the sodium salt of mercapto- pyridine oxide in the presence of 2,2-azo-bisisobutyronitrile (AIBN), radical initiator to give a brominated aromatic compound. After etherification and oxidation, 5-iodovaniline was converted to trisubstituted benzene carboxylic acid which give 1-bromo-3-methoxy-4-propoxy-5-iodo- benzene by this new brominating process with a yield of 74 %.

  3. Sorption, degradation, and transport of methyl iodide and other iodine species in geologic media

    International Nuclear Information System (INIS)

    Iodine is an important element in studies of human nutrition to combat I deficiency disorders, and in protection of the environment and human health from anthropogenic release of radioactive I. Biogeochemical cycling of I in the subsurface environment is complex, because it occurs in multiple oxidation states and as inorganic and organic species that may be volatile, hydrophilic and biophilic. Predicting the fate and transport of anthropogenic radioiodine deposited from the atmosphere or released into the subsurface requires knowledge of the sorption and degradation behavior of the various I species that may interact with soils and sediments. In this study, sorption, degradation, and transport behavior of I species (iodide, iodate, methyl iodide, and 4-iodoaniline) were examined in 12 geologic samples of differing physico-chemical characteristics, collected at numerous nuclear facilities in the USA. In particular, this work focuses on the sorption and degradation behavior of CH3I in geologic media, for which few studies are available, even though it is recognized as an important gaseous form of I in the marine atmosphere, and as a major form released from nuclear fuel reprocessing facilities and during nuclear accidents. Results from complementary batch and column experiments show that different I species exhibit very different sorption and transport behavior in geologic media. Sorption of I− is in general minimal, but a low concentration (5 10−13 M) of radioactive 125I is found to be strongly sorbed onto samples with high organic matter. Sorption of IO3- is consistently greater than that of I−, and sorption of 4-iodoaniline is generally strong and seems to be related to the amount of organic matter in the media. Methyl iodide is weakly sorbed onto 12 geologic samples with a distribution coefficient of about 1 mL/g, but its degradation varies greatly as a function of organic matter content, with a regression line of t1/2 = 0.084 × OM + 0.088 (R2 = 0.898, N

  4. Cyclization of 2′-hydroxychalcones to flavones using ammonium iodide as an iodine source: An eco-friendly approach

    OpenAIRE

    Kulkarni Pramod S.; Kondhare Dasharath D.; Varala Ravi; Zubaidha Pudukulathan K.

    2013-01-01

    Ammonium iodide in open air decomposes to ammonia and iodine. The in situ generated iodine has been used for cyclization of 2′-hydroxychalcones to corresponding flavones under solvent free conditions with good to excellent yields. This method would serve as an attractive alternative to the existing methods for synthesis of flavones and use of toxic molecular iodine is avoided.

  5. Cyclization of 2′-hydroxychalcones to flavones using ammonium iodide as an iodine source: An eco-friendly approach

    Directory of Open Access Journals (Sweden)

    Kulkarni Pramod S.

    2013-01-01

    Full Text Available Ammonium iodide in open air decomposes to ammonia and iodine. The in situ generated iodine has been used for cyclization of 2′-hydroxychalcones to corresponding flavones under solvent free conditions with good to excellent yields. This method would serve as an attractive alternative to the existing methods for synthesis of flavones and use of toxic molecular iodine is avoided.

  6. Polymer adsorption and its effect on the Stability of hydrophobic colloids. III. Kinetics of th Flocculation of silver iodide sols

    NARCIS (Netherlands)

    Fleer, G.J.; Lyklema, J.

    1976-01-01

    In a previous study on the flocculation of silver iodide sols by polyvinyl alcohol (PVA) it was demonstrated that the extent of flocculation depends critically on the way in which sol particles and polymer are mixed. Optimal flocculation was shown to occur if a two-portion method of mixing is applie

  7. N,N-Dimethylbenzimidazolium iodide as a green catalyst for cross-coupling of aromatic aldehydeswith unactivated imines

    Directory of Open Access Journals (Sweden)

    Viwat Hahnvajana wong

    2016-03-01

    Full Text Available Cross-coupling of aromatic aldehydes with unactivated iminescatalyzed by N,N-dimethylbenzimidazolium iodide in ethanolic sodium hydroxide solution gave α-amino ketonesin satisfactory yields. Benzoin condensation and further oxidation of the resulted aroins also occurred as side reactions.

  8. Efficient Method for the Determination of the Activation Energy of the Iodide-Catalyzed Decomposition of Hydrogen Peroxide

    Science.gov (United States)

    Sweeney, William; Lee, James; Abid, Nauman; DeMeo, Stephen

    2014-01-01

    An experiment is described that determines the activation energy (E[subscript a]) of the iodide-catalyzed decomposition reaction of hydrogen peroxide in a much more efficient manner than previously reported in the literature. Hydrogen peroxide, spontaneously or with a catalyst, decomposes to oxygen and water. Because the decomposition reaction is…

  9. Evaluation of iodide deficiency in the lactating rat and pup using a biologically based dose-response model

    Science.gov (United States)

    A biologically-based dose response (BBDR) model for the hypothalamic-pituitary thyroid (BPT) axis in the lactating rat and nursing pup was developed to describe the perturbations caused by iodide deficiency on the HPT axis. Model calibrations, carried out by adjusting key model p...

  10. Evaluation of iodide deficiency in the lactating rat and pup using a biologically based dose response (BBDR) Model***

    Science.gov (United States)

    A biologically-based dose response (BBDR) model for the hypothalamic-pituitary thyroid (HPT) axis in the lactating rat and nursing pup was developed to describe the perturbations caused by iodide deficiency on the 1-IPT axis. Model calibrations, carried out by adjusting key model...

  11. The lactoperoxidase system : the influence of iodide and the chemical and antimicrobial stability over the period of about 18 months

    NARCIS (Netherlands)

    Bosch, EH; Van Doorne, H; De Vries, S

    2000-01-01

    The lactoperoxidase (LP) system is a natural antimicrobial system, the use of which has been suggested as a preservative in foods and pharmaceuticals. The effect of adding iodide to the LP system, the chemical stability and the change in antimicrobial effectiveness during storage was studied. Additi

  12. Role of endoplasmic reticulum stress-induced apoptosis in rat thyroid toxicity caused by excess fluoride and/or iodide.

    Science.gov (United States)

    Liu, Hongliang; Hou, Changchun; Zeng, Qiang; Zhao, Liang; Cui, Yushan; Yu, Linyu; Wang, Lingzhi; Zhao, Yang; Nie, Junyan; Zhang, Bin; Wang, Aiguo

    2016-09-01

    Excess fluoride and iodide coexist in drinking water in many regions, but few studies have investigated the single or interactive effects on thyroid in vivo. In our study, Wistar rats were exposed to excess fluoride and/or iodide through drinking water for 2 or 8 months. The structure and function of the thyroid, cells apoptosis and the expression of inositol-requiring enzyme 1 (IRE1) pathway-related factors were analyzed. Results demonstrated that excess fluoride and/or iodide could change thyroid follicular morphology and alter thyroid hormone levels in rats. After 8 months treatment, both single and co-exposure of the two microelements could raise the thyroid cells apoptosis. However, the expressions of IRE1-related factors were only increased in fluoride-alone and the combined groups. In conclusion, thyroid structure and thyroid function were both affected by excess fluoride and/or iodide. IRE1-induced apoptosis were involved in this cytotoxic process caused by fluoride or the combination of two microelements. PMID:27522547

  13. Congenital Hypothyroidism Caused by a PAX8 Gene Mutation Manifested as Sodium/Iodide Symporter Gene Defect

    Directory of Open Access Journals (Sweden)

    Wakako Jo

    2010-01-01

    Full Text Available Loss-of-function mutations of the PAX8 gene are considered to mainly cause congenital hypothyroidism (CH due to thyroid hypoplasia. However, some patients with PAX8 mutation have demonstrated a normal-sized thyroid gland. Here we report a CH patient caused by a PAX8 mutation, which manifested as iodide transport defect (ITD. Hypothyroidism was detected by neonatal screening and L-thyroxine replacement was started immediately. Although 123I scintigraphy at 5 years of age showed that the thyroid gland was in the normal position and of small size, his iodide trapping was low. The ratio of the saliva/plasma radioactive iodide was low. He did not have goiter; however laboratory findings suggested that he had partial ITD. Gene analyses showed that the sodium/iodide symporter (NIS gene was normal; instead, a mutation in the PAX8 gene causing R31H substitution was identified. The present report demonstrates that individuals with defective PAX8 can have partial ITD, and thus genetic analysis is useful for differential diagnosis.

  14. Grain-Size-Limited Mobility in Methylammonium Lead Iodide Perovskite Thin Films

    Energy Technology Data Exchange (ETDEWEB)

    Reid, Obadiah G.; Yang, Mengjin; Kopidakis, Nikos; Zhu, Kai; Rumbles, Garry

    2016-09-09

    We report a systematic study of the gigahertz-frequency charge carrier mobility found in methylammonium lead iodide perovskite films as a function of average grain size using time-resolved microwave conductivity and a single processing chemistry. Our measurements are in good agreement with the Kubo formula for the AC mobility of charges confined within finite grains, suggesting (1) that the surface grains imaged via scanning electron microscopy are representative of the true electronic domain size and not substantially subdivided by twinning or other defects not visible by microscopy and (2) that the time scale of diffusive transport across grain boundaries is much slower than the period of the microwave field in this measurement (-100 ps). The intrinsic (infinite grain size) minimum mobility extracted form the model is 29 +/- 6 cm2 V-1 s-1 at the probe frequency (8.9 GHz).

  15. Photoemission and optical constant measurements of Cesium Iodide thin film photocathode

    CERN Document Server

    Triloki,; Gupta, Nikita; Jammal, Nabeel F A; Singh, B K

    2014-01-01

    Performance of cesium iodide (CsI) as a reflective photocathode is presented. Absolute quantum efficiency (QE) measurement of 500 nm thick CsI film has been carried out in the wavelength range of 150 nm to 200 nm. Optical absorbance of 500 nm thick CsI film in the spectral range of 190 nm to 900 nm is analyzed and optical energy band gap is calculated using Tauc plot. To see the dispersive behavior of CsI film, refractive index has been determined by envelop plot of transmittance data, using Swanepoel method. Additional information on morphological and elemental composition results of CsI film, gained by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS), respectively are also reported in present work.

  16. Coordination-Induced Syntheses of Two Hybrid Framework Iodides: A Thermochromic Luminescent Thermometer.

    Science.gov (United States)

    Zhang, Ren-Chun; Wang, Jun-Jie; Zhang, Jing-Chao; Wang, Meng-Qi; Sun, Min; Ding, Feng; Zhang, Dao-Jun; An, Yong-Lin

    2016-08-01

    Two new 3D hybrid framework iodides, Hmta[(Hmta)Ag4I4] (1; Hmta = hexamethylenetetramine) and [(Hmta)2Ag8I6]I2 (2), have been synthesized under solvothermal conditions. Compound 1 consists of a neutral 3D framework built up from alternation of the tetrahedral Ag4I4 unit and Hmta with dia-b topology. Compound 2 features a 3D cationic framework with flu topology, constructed by cationic [Ag8I6](2+) units linked with Hmta. Tetrahedral Hmta plays crucial structure-directing roles in the formation of these 3D frameworks with high symmetry. The temperature-dependent photoluminescent measurement reveals luminescent thermochromism of the compounds, the emission maximum of which shows a gradual blue shift with increasing temperature. The results indicate that 1 is a promising wavelength- and intensity-dependent luminescent thermometer applicable in two different temperature ranges. PMID:27438190

  17. A review of recent measurements of optical and thermal properties of. alpha. -mercuric iodide

    Energy Technology Data Exchange (ETDEWEB)

    Burger, A.; Morgan, S.H.; Silberman, E. (Fisk Univ., Nashville, TN (United States). Dept. of Physics); Nason, D.; Cheng, A.Y. (EG and G Energy Measurements, Inc., Goleta, CA (United States). Santa Barbara Operations)

    1991-01-01

    The knowledge of the physical properties of a crystal and their relation to the nature and content of defects are essential for both applications and fundamental reasons. Alpha-mercuric iodide ({alpha}-HgI{sub 2}) is a material which was found important applications as room temperature X-ray and gamma ray detectors. Some recent thermal and optical measurements of this material, using the samples of improved crystallinity which are now available, are reviewed below. Heretofore, these properties have received less attention than the mechanical and electrical properties, particularly at elevated temperatures. In the technology of {alpha}-HgI{sub 2} where there is a continuing motivation to obtain larger single crystals without compromising the material quality, a better knowledge of the thermal and optical properties may lead to improvements in the processes of material purification, crystal growth and device fabrication.

  18. Electric field effects on the quantum efficiency of Cesium-iodide photocathodes in gas media

    International Nuclear Information System (INIS)

    We have measured the quantum efficiency (QE) of Cesium iodide photocathodes as a function of the electric field strength in a parallel-plate geometry, in CH4, C2H6 AND i-C4H10 both in charge collection and multiplication modes. It was found that in the collection mode the QE value in gases is lower compared to that of vacuum and is independent on the field; in gas media the QE starts to increase at the transition between collection and multiplication modes and reaches the vacuum value at high gas gain. We explain this effect by a decrease of the electron-molecule elastic backscattering while entering the multiplication mode. We conclude that the electric field effects observed here, would also apply for other photocathodes and gas mixtures. An enhancement of the QE after micro discharges was observed and is discussed in detail. (authors) 30 refs, 10 figs

  19. Efficient organic solar cells using copper(I) iodide (CuI) hole transport layers

    International Nuclear Information System (INIS)

    We report the fabrication of high power conversion efficiency (PCE) polymer/fullerene bulk heterojunction (BHJ) photovoltaic cells using solution-processed Copper (I) Iodide (CuI) as hole transport layer (HTL). Our devices exhibit a PCE value of ∼5.5% which is equivalent to that obtained for control devices based on the commonly used conductive polymer poly(3,4-ethylenedioxythiophene): polystyrenesulfonate as HTL. Inverted cells with PCE >3% were also demonstrated using solution-processed metal oxide electron transport layers, with a CuI HTL evaporated on top of the BHJ. The high optical transparency and suitable energetics of CuI make it attractive for application in a range of inexpensive large-area optoelectronic devices

  20. A coupled chemical burster: The chlorine dioxide-iodide reaction in two flow reactors

    Science.gov (United States)

    Dolnik, Milos; Epstein, Irving R.

    1993-01-01

    The dynamical behavior of the chlorine dioxide-iodide reaction has been studied in a system consisting of two continuous flow stirred tank reactors (CSTRs). The reactors are coupled by computer monitoring of the electrochemical potential in each reactor, which is then used to control the input into the other reactor. Two forms of coupling are employed: reciprocally triggered, exponentially decreasing stimulation, and alternating mass exchange. The reaction, which exhibits oscillatory and excitable behavior in a single CSTR, displays neuronlike bursting behavior with both forms of coupling. Reciprocal stimulation yields bursting in both reactors, while with alternating mass exchange, bursting is observed in one reactor and complex oscillation in the other. A simple model of the reaction gives good agreement between the experimental observations and numerical simulations.

  1. Lead iodide films as X-ray sensors tested in the mammography energy region

    International Nuclear Information System (INIS)

    We present an alternative method for the deposition of thin films of lead iodide (PbI2), which is a promising semiconductor candidate for applications in medical digital radiography. The spray pyrolysis technique enables the fabrication of thick films with a deposition rate of about 3.3 As-1. We investigate the influence of the main deposition parameters on the final properties of the films. They were substrate temperature from 150 up to 270 oC and nozzle-spray distance to substrate from 13.0 to 16.5 cm. The films were mainly investigated using X-ray diffraction (XRD), Atomic Force Microscopy (AFM), and Photoluminescence (PL) spectroscopy. Also, electrical characterizations were made in the dark as a function of temperature, and with the samples submitted to X-ray exposures in the energy range of mammography diagnosis

  2. Mercuric iodide composite films using polyamide, polycarbonate and polystyrene fabricated by casting

    International Nuclear Information System (INIS)

    Mercuric iodide (HgI2) composite films were obtained by using the casting technique. Insulator polymers such as polyamide, polycarbonate and polystyrene were mixed to HgI2 crystallites forming a final sub-millimeter thick self-standing film. Fabrication temperature varied from 10 to 100 oC, and total fabrication time reached at most 5 min. The larger the fabrication temperature, the thinner the film and the smaller its electrical resistivity. Electrical characterization was performed in the dark, under UV illumination and under mammographic X-ray exposure. The final properties of the films are discussed and related to fabrication conditions. The optimized composite film might be a better candidate for use as X-ray detector for medical imaging, in place of the single HgI2 crystalline device.

  3. Electron and Hole Drift Mobility Measurements on Methylammonium Lead Iodide Perovskite Solar Cells

    Energy Technology Data Exchange (ETDEWEB)

    Maynard, Brian; Long, Qi; Schiff, Eric A.; Yang, Mengjin; Zhu, Kai; Kottokkaran, Ranjith; Abbas, Hisham; Dalal, Vikram L.

    2016-04-25

    We report nanosecond domain time-of-flight measurements of electron and hole photocarriers in methylammonium lead iodide perovskite solar cells. The mobilities ranged from 0.06 to 1.4 cm2/Vs at room temperature, but there is little systematic difference between the two carriers. We also find that the drift mobilities are dispersive (time-dependent). The dispersion parameters are in the range of 0.4-0.7, and they imply that terahertz domain mobilities will be much larger than nanosecond domain mobilities. The temperature-dependences of the dispersion parameters are consistent with confinement of electron and hole transport to fractal-like spatial networks within nanoseconds of their photogeneration.

  4. Determination of iodide by volumetric titration in support of the oil eletrolabeling with {sup 123}I

    Energy Technology Data Exchange (ETDEWEB)

    Kenup-Cantuaria, Hericka O.H.; Brandao, Luis E.B., E-mail: hkenup@ien.gov.br, E-mail: brandao@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Silva, Ademir X., E-mail: ademir@nuclear.ufrj.br [Coordenacao dos Programas de Pos-Graduacao em Engenharia (PEN/COPPE/UFRJ), Rio de Janeiro, RJ (Brazil). Programa de Engenharia Nuclear

    2015-07-01

    The accuracy in measuring flow rate in pipelines is essential task to control various technical parameters in an industrial plant in oil industry and its derivatives. For this reason, it becomes increasingly widespread the uses of organic molecules labeled with radioactive isotopes mainly because of the wide possibility in use of different radioisotopes also due to the new labeling techniques. This paper presents a study to develop an electrochemical technique for oil labeling with iodine -123 and to determine the yield of production by measuring the concentration of iodide (I{sup -}) during this process. The volumetric titration technique was applied as a basis for quantitative and qualitative measures to monitor the labeling process. The results indicate the technical proposal as a viable alternative for monitoring electro labeling process of lubricating oils with iodine -123. (author)

  5. Cell Cycle Analysis of CML Stem Cells Using Hoechst 33342 and Propidium Iodide.

    Science.gov (United States)

    DeSouza, Ngoc; Zhou, Megan; Shan, Yi

    2016-01-01

    Chronic myeloid leukemia (CML) is a myeloproliferative disease with an expansion of white blood cells. The current treatments for CML are shown not to be long-term effective because of CML stem cells' insensitivity to tyrosine kinase inhibitors. Therefore, studying more about CML stem cells is essential to understand the pathways of CML stem cell development and proliferation and finally lead to effective treatments to eliminate CML stem cells and eradicate CML. This chapter describes two methods to analyze cell cycle of CML stem cells. The rare population of CML stem cells can be identified by staining with cell surface markers, and then DNA-binding dyes Hoechst 33342 and propidium iodide (PI) are added to stain the DNA content which is changed when cells go through different phases of the cell cycle. Samples are run through the flow cytometer to be analyzed based on different absorbance and emission wavelengths of different florescent colors. PMID:27581138

  6. Growth of single crystals of mercuric iodide (HgI2) in spacelab III

    International Nuclear Information System (INIS)

    Continued development of a system designed to grow crystals by physical vapor transport in the environment of Spacelab III will be described, with special emphasis on simulation of expected space conditions, adjustment of crystal growth parameters, and on board observation and control of the experiment by crew members and ground personnel. A critical factor in the use of mercuric iodide for semiconductor detectors of x-rays and gamma-rays is the crystalline quality of the material. The twofold purpose of the Spacelab III experiment is therefore to grow single crystals with superior electronic properties as an indirect result of the greatly reduced gravity field during the growth, and to obtain data which will lead to improved understanding of the vapor transport mechanism. The experiments planned to evaluate the space crystals, including gamma-ray diffractometry and measurements of stoichiometry, lattice dimensions, mechanical strength, luminescense, and detector performance are discussed

  7. Conductivity and electrical properties of corn starch-chitosan blend biopolymer electrolyte incorporated with ammonium iodide

    Science.gov (United States)

    Yusof, Y. M.; Shukur, M. F.; Illias, H. A.; Kadir, M. F. Z.

    2014-03-01

    This work focuses on the characteristics of polymer blend electrolytes based on corn starch and chitosan doped with ammonium iodide (NH4I). The electrolytes were prepared using the solution cast method. A polymer blend comprising 80 wt% starch and 20 wt% chitosan was found to be the most amorphous blend and suitable to serve as the polymer host. Fourier transform infrared spectroscopy analysis proved the interaction between starch, chitosan and NH4I. The highest room temperature conductivity of (3.04 ± 0.32) × 10-4 S cm-1 was obtained when the polymer host was doped with 40 wt% NH4I. This result was further proven by field emission scanning electron microscopy study. All electrolytes were found to obey the Arrhenius rule. Dielectric studies confirm that the electrolytes obeyed non-Debye behavior. The temperature dependence of the power law exponent s for the highest conducting sample follows the quantum mechanical tunneling model.

  8. Role of -methyl-8-(alkoxy)quinolinium iodide in suppression of protein-protein interactions

    Indian Academy of Sciences (India)

    Bimlesh Ojha; Cirantan Kar; Gopal Das

    2013-03-01

    There is a great deal of interest in developing small molecule inhibitors of protein misfolding and aggregation due to a growing number of pathologic states known as amyloid disorders. In searching for alternative ways to reduce protein-protein interactions or to inhibit the amyloid formation, the inhibitory effects of cationic amphiphile viz. -methyl-8-(alkoxy)quinolinium iodide on aggregation behaviour of hen egg white lysozyme (HEWL) at alkaline pH has been studied. Even though the compounds did not protect native HEWL from conformational changes, they were effective in diminishing HEWL amyloid formation, delaying both nucleation and elongation phases. It is likely that strong binding in the HEWL compound complex, raises the activation energy barrier for protein misfolding and subsequent aggregation, thereby retarding the aggregation kinetics substantially.

  9. The Inhibition Effect of Potassium Iodide on the Corrosion of Pure Iron in Sulphuric Acid

    Directory of Open Access Journals (Sweden)

    Tarik Attar

    2014-01-01

    Full Text Available The use of inorganic inhibitors as an alternative to organic compounds is based on the possibility of degradation of organic compounds with time and temperature. The inhibition effect of potassium iodide on the corrosion of pure iron in 0.5 M H2SO4 has been studied by weight loss. It has been observed from the results that the inhibition efficiency (IE% of KI increases from 82.17% to 97.51% with the increase in inhibitor concentration from 1·10−4 to 2·10−3 M. The apparent activation energy (Ea and the equilibrium constant of adsorption (Kads were calculated. The adsorption of the inhibitor on the pure iron surface is in agreement with Langmuir adsorption isotherm.

  10. Electron and hole drift mobility measurements on methylammonium lead iodide perovskite solar cells

    Science.gov (United States)

    Maynard, Brian; Long, Qi; Schiff, Eric A.; Yang, Mengjin; Zhu, Kai; Kottokkaran, Ranjith; Abbas, Hisham; Dalal, Vikram L.

    2016-04-01

    We report nanosecond domain time-of-flight measurements of electron and hole photocarriers in methylammonium lead iodide perovskite solar cells. The mobilities ranged from 0.06 to 1.4 cm2/Vs at room temperature, but there is little systematic difference between the two carriers. We also find that the drift mobilities are dispersive (time-dependent). The dispersion parameters are in the range of 0.4-0.7, and they imply that terahertz domain mobilities will be much larger than nanosecond domain mobilities. The temperature-dependences of the dispersion parameters are consistent with confinement of electron and hole transport to fractal-like spatial networks within nanoseconds of their photogeneration.

  11. Influence of ionic strength on the transport parameters of tritiated water and iodide in boom clay

    International Nuclear Information System (INIS)

    To fulfil its role as main barrier for High and Medium Level radioactive waste (HLW and MLW), Boom Clay relies on its advantageous capacity to minimise radionuclide transport by its slow diffusion and high retention properties. One of the key parameters in the radionuclide dispersion process is the diffusion accessible porosity (ηacc). Diffusion accessible porosity, is a transport parameter that is linked to the properties of each dispersing radionuclide and the geochemical conditions of Boom Clay. Disposing radioactive waste in Boom Clay will inevitably cause perturbations of which some can generate changes in the Boom Clay pore water chemistry. One effect of these chemical perturbations will be the increase of ionic strength of the pore water in the vicinity of a repository. This paper synthesises the results of the experimental work done to obtain the transport parameters of tritiated water and iodide for Boom Clay at different ionic strengths. (authors)

  12. Diphenyleneiodonium, an inhibitor of NOXes and DUOXes, is also an iodide-specific transporter

    Directory of Open Access Journals (Sweden)

    C. Massart

    2014-01-01

    Full Text Available NADPH oxidases (NOXes and dual oxidases (DUOXes generate O2.− and H2O2. Diphenyleneiodonium (DPI inhibits the activity of these enzymes and is often used as a specific inhibitor. It is shown here that DPI, at concentrations similar to those which inhibit the generation of O2 derivatives, activated the efflux of radioiodide but not of its analog 99mTcO4− nor of the K+ cation mimic 86Rb+ in thyroid cells, in the PCCl3 rat thyroid cell line and in COS cell lines expressing the iodide transporter NIS. Effects obtained with DPI, especially in thyroid cells, should therefore be interpreted with caution.

  13. A method for objectively quantifying propidium iodide exclusion in organotypic hippocampal slice cultures

    DEFF Research Database (Denmark)

    Happ, Denise F; Tasker, Andrew

    2016-01-01

    BACKGROUND: Organotypic hippocampal slice cultures (OHSCs) are an attractive in vitro model to examine mechanisms of neuronal injury, because the normal hippocampal architecture, function and cellular diversity are mostly preserved. The effects of exposure to excitotoxins such as N......-methyl-d-aspartate (NMDA) on cell viability can be determined by propidium iodide (PI) staining. NEW METHOD: We describe a simple method to objectively quantify cell death in NMDA exposed slice cultures using PI that provides a standardized means of quantifying cell death in hippocampal subfields without the need to...... induce maximal cell death in each slice. The method employs separation of subfields using simple landmarks and densitometric quantification of PI intensity in 10 template-oriented counting fields. RESULTS: We show that exposure to increasing concentrations of NMDA results in a dose-dependent increase in...

  14. Thermodynamics of iodide adsorption at the instantaneous air-water interface

    Science.gov (United States)

    Stern, Abraham C.; Baer, Marcel D.; Mundy, Christopher J.; Tobias, Douglas J.

    2013-03-01

    We performed molecular dynamics simulations using both polarizable and non-polarizable force fields to study the adsorption of iodide to the air-water interface. A novel aspect of our analysis is that the progress of ion adsorption is measured as the distance from the instantaneous interface, which is defined by a coarse-graining scheme proposed recently by Willard and Chandler ["Instantaneous liquid interfaces," J. Phys. Chem. B 114, 1954-1958 (2010), 10.1021/jp909219k]. Referring structural and thermodynamic quantities to the instantaneous interface unmasks molecular-scale details that are obscured by thermal fluctuations when the same quantities are referred to an average measure of the position of the interface, such as the Gibbs dividing surface. Our results suggest that an ion adsorbed at the interface resides primarily in the topmost water layer, and the interfacial location of the ion is favored by enthalpy and opposed by entropy.

  15. Cesium-iodide-based nanocrystal for the detection of ionizing radiation

    Science.gov (United States)

    Farzaneh, Azadeh; Abdi, Mohammad Reza; Saraee, Khadijeh Rezaee Ebrahim; Mostajaboddavati, Mojtaba; Quaranta, A.

    2016-05-01

    We report on the synthesis of cesium-iodide nanoparticles using sol-gel technique. The structural properties of CsI nanoparticles were characterized by X-ray diffraction and optical properties were followed by optical absorption and UV-vis fluorescence. Intense photoluminescence is also observed, with some spectral tuning possible with ripening time getting a range of emission photon wavelength approximately from 366 to 350 nm. The size effect on CsI luminescence leads to an increase in scintillation light yield, a redshift of the emission bands of the on_center and off_center self_trapped excitons (STEs) and an increase in the contribution of the off_center STEs to the net intrinsic emission yield. The energy transfer from the matrix to CsI nanoparticles is a key characteristic for scintillation detectors. So the scintillation spectra and decay curve to alpha particles of sample were monitored.

  16. Efficient organic solar cells using copper(I) iodide (CuI) hole transport layers

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Ying [Key Laboratory of Luminescence and Optical Information, Ministry of Education, Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044 (China); Department of Physics and Centre for Plastic Electronics, Blackett Laboratory, Imperial College London, London SW7 2AZ (United Kingdom); Yaacobi-Gross, Nir; Perumal, Ajay K.; Faber, Hendrik A.; Bradley, Donal D. C.; Anthopoulos, Thomas D., E-mail: zhqhe@bjtu.edu.cn, E-mail: t.anthopoulos@imperial.ac.uk [Department of Physics and Centre for Plastic Electronics, Blackett Laboratory, Imperial College London, London SW7 2AZ (United Kingdom); Vourlias, George; Patsalas, Panos A. [Department of Physics, Laboratory of Applied Physics, Aristotle University of Thessaloniki, GR-54124 Thessaloniki (Greece); He, Zhiqun, E-mail: zhqhe@bjtu.edu.cn, E-mail: t.anthopoulos@imperial.ac.uk [Key Laboratory of Luminescence and Optical Information, Ministry of Education, Institute of Optoelectronic Technology, Beijing Jiaotong University, Beijing 100044 (China)

    2015-06-15

    We report the fabrication of high power conversion efficiency (PCE) polymer/fullerene bulk heterojunction (BHJ) photovoltaic cells using solution-processed Copper (I) Iodide (CuI) as hole transport layer (HTL). Our devices exhibit a PCE value of ∼5.5% which is equivalent to that obtained for control devices based on the commonly used conductive polymer poly(3,4-ethylenedioxythiophene): polystyrenesulfonate as HTL. Inverted cells with PCE >3% were also demonstrated using solution-processed metal oxide electron transport layers, with a CuI HTL evaporated on top of the BHJ. The high optical transparency and suitable energetics of CuI make it attractive for application in a range of inexpensive large-area optoelectronic devices.

  17. {sup 11}C-methylations using {sup 11}C-methyl iodide and tetrabutylammonium fluoride

    Energy Technology Data Exchange (ETDEWEB)

    Adam, M.J.; Jivan, S.; Huser, J.M.; Lu, J. [TRIUMF Univ. of British Columbia, Vancouver (Canada)

    2000-07-01

    Carbon-11 methylation reactions on functional groups such as phenols and amides require a base when using {sup 11}C-methyl iodide. This study demonstrates that tetrabutylammonium fluoride (TBAF) can be used as a base to prepare {sup 11}C-radiopharmaceuticals efficiently and in high yield. We have applied this method to raclopride, methylphenidate, PK11195, dihydrotetrabenazine and MDL100907 and have compared the results with the Alumina/KF and hydroxide methods. Our results indicate that TBAF gives equivalent or higher radiochemical yields compared to the other bases even when using as little as 200 {mu}g of precursor. In the case of PK11195 the TBAF method was the only one that provided a reasonable yield of product. (orig.)

  18. Chemistry of recoil atoms of bromine-82 in neutron-irradiated crystalline perbromates of the alkali metals and ammonium

    Energy Technology Data Exchange (ETDEWEB)

    Gavrilov, V.V.; Isupov, V.K.; Kirin, I.S.

    1975-01-01

    It was established by ion exchange chromatography that the recoil atoms of bromine-82 in perbromates with thermal neutrons are stabilized in the form of five valence forms: BrO/sub 4//sup -/, BrO/sub 3//sup -/, BrO/sub 2//sup -/, BrO/sup -/, Br/sup -/. The retention of bromine-82 of BrO/sub 4//sup -/ is 2.1 +- 0.4 percent for LiBrO/sub 4/, 2.1 +- 0.4 percent for NaBrO/sub 4/, 2.3 +- 0.4 percent for KBrO/sub 4/, 2.6 +- 0.4 percent for RbBrO/sub 4/, 2.2 +- 0.4 percent for CsBrO/sub 4/, and 1.6 +- 0.4 percent for NH/sub 4/BrO/sub 4/.

  19. Silver nanoplates-based colorimetric iodide recognition and sensing using sodium thiosulfate as a sensitizer

    International Nuclear Information System (INIS)

    Highlights: • A new colorimetric iodide detection strategy based on triangular Ag nanoplate. • Sodium thiosulfate performed as a sensitizer. • Formation of insoluble AgI on the surface of Ag nanoplate. • This method has the advantages of good selectivity and high sensitivity. - Abstract: A colorimetric method for the recognition and sensing of iodide ions (I−) has been developed by utilizing the reactions between triangular silver nanoplates (TAg-NPs) and I− in the presence of sodium thiosulfate (Na2S2O3). Specifically, I− together with Na2S2O3 can induce protection of TAg-NPs owing to the formation of insoluble AgI, as confirmed by the high-resolution transmission electron microscopy (HRTEM). In the absence of Na2S2O3, the etching reactions on TAg-NPs were observed not only by I− but also other halides ions. The Na2S2O3 plays as a sensitizer in this system, which improved the selectivity and sensitivity. The desired colorimetric detection can be achieved by measuring the change of the absorption peak wavelength corresponding to localized surface plasmon resonance (LSPR) with UV–vis spectrophotometer or recognized by naked eye observation. The results show that the shift of the maximum absorption wavelength (Δλ) of the TAg-NPs/Na2S2O3/I mixture was proportional to the concentration of I− in the range 1.0 × 10−9–1.0 × 10−6 mol L−1. Moreover, no other ions besides I− can induce an eye discernible color change as low as 1.0 × 10−7 mol L−1. Finally, this method was successfully applied for I− determination in kelp samples

  20. Expression of sodium/iodide symporter transgene in neural stem cells

    International Nuclear Information System (INIS)

    The ability to noninvasively track the migration of neural progenitor cells would have significant clinical and research implications. We generated stably transfected F3 human neural progenitor cells with human sodium/iodide symporter (hNIS) for noninvasively tracking F3. In this study, the expression patterns of hNIS gene in F3-NIS were examined according to the cultured time and the epigenetic modulation. F3 human neural stem cells had been obtained from Dr. Seung U. Kim (Ajou University, Suwon, Korea). hNIS and hygromycin resistance gene were linked with IRES (internal Ribosome Entry Site) under control of CMV promoter. This construct was transfected to F3 with Liposome. To investigate the restoration of hNIS gene expression in F3-NIS, cells were treated with demethylating agent (5-Azacytidine) and Histone deacetylase inhibitor (Trichostatin A: TSA). The expression of hNIS was measured by I-125 uptake assay and RT-PCR analysis. The iodide uptake of the F3-NIS was higher 12.86 times than F3 cell line. According to the cell passage number, hNIS expression in F3-NIS gradually diminished. After treatment of 5-Azacytidine and TSA with serial doses (up to 20μM, up to 62.5nM, respectively) for 24 hours, I-125 uptake and mRNA of hNIS in F3-NIS were increased. These results suggest that hNIS transfected F3 might undergo a change in its biological characters by cell passage. Therefore, the gene expression of exogenous gene transferred human stem cell might be affected to the epigenetic modulation such as promoter methylation and Histone deacetylation and to the cell culture conditions