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Sample records for salts selective fluorination

  1. Effect of Quaternary Ammonium Salts with Fluorine Atoms on Selected Weed Species.

    Science.gov (United States)

    Biczak, Robert; Pawłowska, Barbara; Płatkowski, Maciej; Stręk, Michał; Telesiński, Arkadiusz

    2017-04-01

    This study investigated the effects of four structurally different quaternary ammonium salts (QASs), i.e., tetrabutylammonium tetrafluoroborate [TBA][BF 4 ], tetrahexylammonium tetrafluoroborate [THA][BF 4 ], tetrabutylammonium hexafluorophosphate [TBA][PF 6 ], and tetrahexylammonium hexafluorophosphate [THA][PF 6 ], on the growth and development of three weed species: gallant soldier (Galinsoga parviflora Cav.), white goosefoot (Chenopodium album L.) and common sorrel (Rumex acetosa L.). The examined compounds were applied in the form of foliar spraying and soil application. Strong herbicidal properties of the examined compounds were demonstrated in case of their soil application. Growth inhibition of plant shoots and roots was greater with soil application than with foliar treatment. The strongest herbicidal activity of compounds was demonstrated with [TBA][BF 4 ] have demonstrated [TBA][BF 4 ] and [TBA][PF 6 ] applied to the soil, while [THA][BF 4 ] demonstrated the weakest herbicidal action. The increased concentration of applied QASs caused a decrease in the assimilation pigments, change in dry weight content and inhibition of length of shoots and roots.

  2. Fluoroalkyl containing salts combined with fluorinated solvents for electrolytes

    Science.gov (United States)

    Tikhonov, Konstantin; Yip, Ka Ki; Lin, Tzu-Yuan; Erickson, Michael Jason

    2015-04-21

    Provided are electrochemical cells and electrolytes used to build such cells. An electrolyte may include a fluoroalkyl-substituted LiPF.sub.6 salt or a fluoroalkyl-substituted LiBF.sub.4 salt. In some embodiments, at least one fluorinated alkyl of the salt has a chain length of from 1 to 8 or, more specifically, between about 2 and 8. These fluorinated alkyl groups, in particular, relatively large fluorinated alkyl groups improve solubility of these salts in fluorinated solvents that are less flammable than, for example, conventional carbonate solvents. At the same time, the size of fluoroalkyl-substituted salts should be limited to ensure adequate concentration of the salt in an electrolyte and low viscosity of the electrolyte. In some embodiments, the concentration of a fluoroalkyl-substituted salt is at least about 0.5M. Examples of fluorinated solvents include various fluorinated esters, fluorinated ethers, and fluorinated carbonates, such a 1-methoxyheptafluoropropane, methyl nonafluorobutyl ether, ethyl nonafluorobutyl ether, 1,1,1,2,2,3,4,5,5,5-decafluoro-3-methoxy-4-(trifluoromethyl)-pentane, 3-ethoxy-1,1,1,2,3,4,4,5,5,6,6,6-dodecafluoro-2-trifluoromethyl-hexane, and 1,1,1,2,3,3-hexafluoro-4-(1,1,2,3,3,3-hexafluoropropoxy)-pentane.

  3. Combinations of fluorinated solvents with imide salts or methide salts for electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Tikhonov, Konstantin; Yip, Ka Ki; Lin, Tzu-Yuan; Lei, Norman; Guerrero-Zavala, Guillermo; Kwong, Kristie W

    2015-11-10

    Provided are electrochemical cells and electrolytes used to build such cells. The electrolytes include imide salts and/or methide salts as well as fluorinated solvents capable of maintaining single phase solutions at between about -30.degree. C. to about 80.degree. C. The fluorinated solvents, such as fluorinated carbonates, fluorinated esters, and fluorinated esters, are less flammable than their non-fluorinated counterparts and improve safety characteristics of cells containing these solvents. The amount of fluorinated solvents in electrolytes may be between about 30% and 80% by weight not accounting weight of the salts. Linear and cyclic imide salts, such as LiN(SO.sub.2CF.sub.2CF.sub.3).sub.2, and LiN(SO.sub.2CF.sub.3).sub.2, as well as methide salts, such as LiC(SO.sub.2CF.sub.3).sub.3 and LiC(SO.sub.2CF.sub.2CF.sub.3).sub.3, may be used in these electrolytes. Fluorinated alkyl groups enhance solubility of these salts in the fluorinated solvents. In some embodiments, the electrolyte may also include a flame retardant, such as a phosphazene, and/or one or more ionic liquids.

  4. Low molecular weight salts combined with fluorinated solvents for electrolytes

    Science.gov (United States)

    Tikhonov, Konstantin; Yip, Ka Ki; Lin, Tzu-Yuan; Lei, Norman; Guerrero-Zavala, Guillermo; Kwong, Kristie W.

    2015-11-10

    Provided are electrochemical cells and electrolytes used to build such cells. An electrolyte includes at least one salt having a molecular weight less than about 250. Such salts allow forming electrolytes with higher salt concentrations and ensure high conductivity and ion transport in these electrolytes. The low molecular weight salt may have a concentration of at least about 0.5M and may be combined with one or more other salts, such as linear and cyclic imide salts and/or methide salts. The concentration of these additional salts may be less than that of the low molecular weight salt, in some embodiments, twice less. The additional salts may have a molecular weight greater than about 250. The electrolyte may also include one or more fluorinated solvents and may be capable of maintaining single phase solutions at between about -30.degree. C. to about 80.degree. C.

  5. 40 CFR 721.4663 - Fluorinated carboxylic acid alkali metal salts.

    Science.gov (United States)

    2010-07-01

    ... metal salts. 721.4663 Section 721.4663 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.4663 Fluorinated carboxylic acid alkali metal salts. (a) Chemical... fluorinated carboxylic acid alkali metal salts (PMNs P-95-979/980/981) are subject to reporting under this...

  6. Fluorine

    Science.gov (United States)

    Hayes, Timothy S.; Miller, M. Michael; Orris, Greta J.; Piatak, Nadine M.; Schulz, Klaus J.; DeYoung, John H.; Seal, Robert R.; Bradley, Dwight C.

    2017-12-19

    is likely to become a source of commercially produced fluorine as a primary product as long as supplies from relatively thick and high-grade fluorite deposits continue to be available.At least seven classes (which include one subclass) of hydrothermal fluorite deposits are recognized; they are classified according to their tectonic and (or) magmatic settings, as follows: (1) carbonatite-related fluorspar deposits; (2) alkaline-intrusion-related fluorspar deposits; (3) alkaline-volcanic-related epithermal fluorspar deposits; (4) Mississippi Valley-type fluorspar deposits (and a subclass of salt-related carbonate-hosted fluorspar deposits); (5) fluorspar deposits related to strongly differentiated granites; (6) subalkaline-volcanic-related epithermal fluospar deposits; and (7) fluorspar deposits that appear to be conformable within tuffaceous limy lacustrine sediments. An eighth class (not hydrothermal) is that of fluorspar deposits concentrated in soils and weathered zones; that is, residual fluorspar deposits. Generally, fluorspar deposits related to strongly differentiated granites have larger tonnages and lower grades than carbonatite-related fluorspar deposits, which, in turn, have larger tonnages and lower grades than fluorspar vein deposits from various other classes.The United States has a few identified resources of fluorspar, most notably the Klondike II property in the Illinois- Kentucky fluorspar district located about 8 kilometers southwest of Salem, Kentucky, which has a large vein that contains at least 1.6 million metric tons at a grade of 60 percent CaF2 (Feytis, 2009). Additional fluorspar resources of lower grade but larger tonnage have been identified at Hicks Dome in the Illinois-Kentucky fluorspar district and at Lost River near the western tip of the Seward Peninsula in Alaska, along with a couple of dozen smaller, higher grade resources.Internationally, new mines that either opened before the beginning of 2013 or were scheduled to open soon

  7. 40 CFR 721.9075 - Quaternary ammonium salt of fluorinated alkylaryl amide.

    Science.gov (United States)

    2010-07-01

    ... fluorinated alkylaryl amide. 721.9075 Section 721.9075 Protection of Environment ENVIRONMENTAL PROTECTION... amide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as quaternary ammonium salt of fluorinated alkylaryl amide (PMN No. P-92-688) is...

  8. Molten Fluoride Salts as Fluorine Source in the Production of Molecular Sidebands

    CERN Document Server

    Shoaib, Maryam

    2015-01-01

    The medically important isotopes Yttrium and Zirconium were selected for fluorination. After this, 30 $\\mu$g of NaF as fluorine source was put in mass marker in the target unit. It was heated and plasma ion source was used to ionize the vapors. The ion source efficiency was 27\\%. It was observed that the yield for fluorine was not enough for various mass marker temperatures (0 A - 40 A) and ion source temperatures (2000 $^{o}$C - 2150$^{o}$C) to be reacted with other elements. The optimum temperatures of mass marker was observed here as 35 A. The project can be proceeded for further high temperatures and for different fluorine sources.

  9. Atmospheric lifetimes of selected fluorinated ether compounds

    DEFF Research Database (Denmark)

    Heathfield, A.E.; Anastasi, C.; Pagsberg, Palle Bjørn

    1998-01-01

    Atmospheric lifetimes have been estimated for a selection of ethers, the latter representing a class of compounds being considered as replacements for chlorofluorocarbons. The estimates are based on laboratory measurements of rate constants for the reaction of the OH radical with the ethers......, and a comparison with the behaviour of methyl chloroform in the atmosphere. The lifetimes for the ethers ranged from a few hours to half a year, significantly lower than those of chlorofluorocarbons and other replacements being considered. (C) 1998 Elsevier Science Ltd. All rights reserved....

  10. Multiple Enone-Directed Reactivity Modes Lead to the Selective Photochemical Fluorination of Polycyclic Terpenoid Derivatives.

    Science.gov (United States)

    Pitts, Cody Ross; Bume, Desta Doro; Harry, Stefan Andrew; Siegler, Maxime A; Lectka, Thomas

    2017-02-15

    In the realm of aliphatic fluorination, the problem of reactivity has been very successfully addressed in recent years. In contrast, the associated problem of selectivity, that is, directing fluorination to specific sites in complex molecules, remains a great, fundamental challenge. In this report, we show that the enone functional group, upon photoexcitation, provides a solution. Based solely on orientation of the oxygen atom, site-selective photochemical fluorination is achieved on steroids and bioactive polycycles with up to 65 different sp(3) C-H bonds. We have also found that γ-, β-, homoallylic, and allylic fluorination are all possible and predictable through the theoretical modes reported herein. Lastly, we present a preliminary mechanistic hypothesis characterized by intramolecular hydrogen atom transfer, radical fluorination, and ultimate restoration of the enone. In all, these results provide a leap forward in the design of selective fluorination of complex substrates that should be relevant to drug discovery, where fluorine plays a prominent role.

  11. Improving the performance of fluorine-doped tin oxide by adding salt

    Energy Technology Data Exchange (ETDEWEB)

    Purwanto, Agus, E-mail: Aguspur@uns.ac.id [Department of Chemical Engineering, Faculty of Engineering, Sebelas Maret University, Jl. Ir. Sutami 36 A, Surakarta, Central Java 57126 (Indonesia); Widiyandari, Hendri [Department of Physics, Faculty of Sciences and Mathematics, Diponegoro University, Jl. Prof. Dr. Soedarto, Tembalang, Semarang 50275 (Indonesia); Suryana, Risa [Department of Physics, Faculty of Mathematics and Natural Sciences, Sebelas Maret University, Jl. Ir. Sutami 36 A, Surakarta, Central Java 57126 (Indonesia); Jumari, Arif [Department of Chemical Engineering, Faculty of Engineering, Sebelas Maret University, Jl. Ir. Sutami 36 A, Surakarta, Central Java 57126 (Indonesia)

    2015-07-01

    High-performance fluorine-doped tin oxide (FTO) films were fabricated via a spray deposition technique with salt added to the precursor. The addition of NaCl in the precursor improved the conductivity of the FTO films. Increasing the NaCl concentration to its optimal concentration reduced the sheet resistance of the FTO film. The optimal values for the addition of a NaCl were 0.5, 0.5, 1.5, and 1.5 at.% for the FTO film prepared using NH{sub 4}F concentration of 4, 10, 16, and 22 at.%, respectively. The lowest sheet resistance of the salt-added FTO film was 4.8 Ω/□. The FTO film averaged a transmittance of more than 80% in the visible range region (λ = 400–800 nm). XRD diffractograms confirmed that the crystal structure of the as-grown FTO film was that of a tetragonal SnO{sub 2} and that the addition of salt improved its crystallinity. This film has the potential for use as an electrode for dye-sensitized solar cells (DSSCs). - Highlights: • A method to improve FTO performance using the addition of salt • The FTO film exhibited high performance of conductivity and light transmittance. • This technique is low-cost, fast and scales-up easily using simple devices.

  12. Fluorine Modulates Species Selectivity in the Triazolopyrimidine Class of Plasmodium falciparum Dihydroorotate Dehydrogenase Inhibitors

    OpenAIRE

    Deng, Xiaoyi; Kokkonda, Sreekanth; El Mazouni, Farah; White, John; Burrows, Jeremy N.; Kaminsky, Werner; Charman, Susan A.; Matthews, David; Rathod, Pradipsinh K.; Phillips, Margaret A.

    2014-01-01

    Malaria is one of the most serious global infectious diseases. The pyrimidine biosynthetic enzyme Plasmodium falciparum dihydroorotate dehydrogenase (PfDHODH) is an important target for antimalarial chemotherapy. We describe a detailed analysis of protein?ligand interactions between DHODH and a triazolopyrimidine-based inhibitor series to explore the effects of fluorine on affinity and species selectivity. We show that increasing fluorination dramatically increases binding to mammalian DHODHs...

  13. Fluorine-free electrolytes for all-solid sodium-ion batteries based on percyano-substituted organic salts

    OpenAIRE

    Anna Bitner-Michalska; Gene M. Nolis; Grażyna Żukowska; Aldona Zalewska; Marcin Poterała; Tomasz Trzeciak; Maciej Dranka; Michał Kalita; Piotr Jankowski; Leszek Niedzicki; Janusz Zachara; Marek Marcinek; Władysław Wieczorek

    2017-01-01

    A new family of fluorine-free solid-polymer electrolytes, for use in sodium-ion battery applications, is presented. Three novel sodium salts withdiffuse negative charges: sodium pentacyanopropenide (NaPCPI), sodium 2,3,4,5-tetracyanopirolate (NaTCP) and sodium 2,4,5-tricyanoimidazolate (NaTIM) were designed andtested in a poly(ethylene oxide) (PEO) matrix as polymer electrolytes for anall-solid sodium-ion battery. Due to unique, non-covalent structural configurations of anions, improved ionic...

  14. Fluorine modulates species selectivity in the triazolopyrimidine class of Plasmodium falciparum dihydroorotate dehydrogenase inhibitors.

    Science.gov (United States)

    Deng, Xiaoyi; Kokkonda, Sreekanth; El Mazouni, Farah; White, John; Burrows, Jeremy N; Kaminsky, Werner; Charman, Susan A; Matthews, David; Rathod, Pradipsinh K; Phillips, Margaret A

    2014-06-26

    Malaria is one of the most serious global infectious diseases. The pyrimidine biosynthetic enzyme Plasmodium falciparum dihydroorotate dehydrogenase (PfDHODH) is an important target for antimalarial chemotherapy. We describe a detailed analysis of protein-ligand interactions between DHODH and a triazolopyrimidine-based inhibitor series to explore the effects of fluorine on affinity and species selectivity. We show that increasing fluorination dramatically increases binding to mammalian DHODHs, leading to a loss of species selectivity. Triazolopyrimidines bind Plasmodium and mammalian DHODHs in overlapping but distinct binding sites. Key hydrogen-bond and stacking interactions underlying strong binding to PfDHODH are absent in the mammalian enzymes. Increasing fluorine substitution leads to an increase in the entropic contribution to binding, suggesting that strong binding to mammalian DHODH is a consequence of an enhanced hydrophobic effect upon binding to an apolar pocket. We conclude that hydrophobic interactions between fluorine and hydrocarbons provide significant binding energy to protein-ligand interactions. Our studies define the requirements for species-selective binding to PfDHODH and show that the triazolopyrimidine scaffold can alternatively be tuned to inhibit human DHODH, an important target for autoimmune diseases.

  15. Recycle waste salt as reagent: a one-pot substitution/Krapcho reaction sequence to α-fluorinated esters and sulfones.

    Science.gov (United States)

    Zhu, Feng; Xu, Peng-Wei; Zhou, Feng; Wang, Cui-Hong; Zhou, Jian

    2015-02-20

    A "one-pot" tandem substitution/Krapcho reaction is reported for the facile synthesis of α-fluorinated esters and sulfones, which utilizes the byproduct salt formed in the substitution step as an indispensible reagent to facilitate the Krapcho reaction step. This represents the first sustainable tandem reaction that internally recycles the waste salt formed in the upstream step as the reagent for the downstream step.

  16. Sulfonium salts as leaving groups for aromatic labelling of drug-like small molecules with fluorine-18.

    Science.gov (United States)

    Sander, Kerstin; Gendron, Thibault; Yiannaki, Elena; Cybulska, Klaudia; Kalber, Tammy L; Lythgoe, Mark F; Årstad, Erik

    2015-04-21

    Positron emission tomography (PET) is unique in that it allows quantification of biochemical processes in vivo, but difficulties with preparing suitably labelled radiotracers limit its scientific and diagnostic applications. Aromatic [(18)F]fluorination of drug-like small molecules is particularly challenging as their functional group compositions often impair the labelling efficiency. Herein, we report a new strategy for incorporation of (18)F into highly functionalized aromatic compounds using sulfonium salts as leaving groups. The method is compatible with pharmacologically relevant functional groups, including aliphatic amines and basic heterocycles. Activated substrates react with [(18)F]fluoride at room temperature, and with heating the reaction proceeds in the presence of hydrogen bond donors. Furthermore, the use of electron rich spectator ligands allows efficient and regioselective [(18)F]fluorination of non-activated aromatic moieties. The method provides a broadly applicable route for (18)F labelling of biologically active small molecules, and offers immediate practical benefits for drug discovery and imaging with PET.

  17. Intermolecular and intramolecular hydrogen bonds involving fluorine atoms: implications for recognition, selectivity, and chemical properties.

    Science.gov (United States)

    Dalvit, Claudio; Vulpetti, Anna

    2012-02-06

    A correlation between 19F NMR isotropic chemical shift and close intermolecular F⋅⋅⋅H-X contacts (with X=N or O) has been identified upon analysis of the X-ray crystal structures of fluorinated molecules listed in the Cambridge Structural Database (CSD). An optimal F⋅⋅⋅X distance involving primary and shielded secondary fluorine atoms in hydrogen-bond formation along with a correlation between F⋅⋅⋅H distance and F⋅⋅⋅H-X angle were also derived from the analysis. The hydrogen bonds involving fluorine are relevant, not only for the recognition mechanism and stabilization of a preferred conformation, but also for improvement in the permeability of the molecules, as shown with examples taken from a proprietary database. Results of an analysis of the small number of fluorine-containing natural products listed in the Protein Data Bank (PDB) appear to strengthen the derived correlation between 19F NMR isotropic chemical shift and interactions involving fluorine (also known as the "rule of shielding") and provides a hypothesis for the recognition mechanism and catalytic activity of specific enzymes. Novel chemical scaffolds, based on the rule of shielding, have been designed for recognizing distinct structural motifs present in proteins. It is envisaged that this approach could find useful applications in drug design for the efficient optimization of chemical fragments or promising compounds by increasing potency and selectivity against the desired biomolecular target. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Selective reactive ion etching of tungsten films in CHF/sub 3/ and other fluorinated gases

    Energy Technology Data Exchange (ETDEWEB)

    Pan, W.S.; Steckl, A.J.

    1988-07-01

    The use of reactive ion etching (RIE ) with fluorinated gas plasmas, such as SF/sub 6/, CF/sub 4/, CBrF/sub 3/, and CHF/sub 3/ mixed with oxygen, to achieve selective patterning of tungsten films is reported. The etch rates of W, Si, and SiO/sub 2/ were measured as a function of oxygen percentage in fluorinated gas plasmas under various conditions. Experiments on selectivity indicate that a CHF/sub 3//70%O/sub 2/ mixture under 20 sccm, 200 W, 20 mTorr etching conditions results in W:Si and W:SiO/sub 2/ etch rate ratios of 1.6:1 and 1.8:1, respectively. Optimized W:Si and W:SiO/sub 2/ selectivity ratios 4:1 and 4.8:1 have been obtained at 60 mTorr/150 W and 260 mTorr/200 W plasma conditions. For reverse selectivity, the optimum W:SiO/sub 2/ etch rate ratio measured is 1:4.6 in pure CHF/sub 3/ gas. The optimum W:Si reverse selectivity of 1:11.6 is obtained with an SF/sub 6//5%O/sub 2/ mixture plasma. A vertical-to-lateral etch ratio of 4:1 was measured with CHF/sub 3//70%O/sub 2/, 200 W, 10 mTorr, 20 sccm. The etching mechanisms of tungsten due to chemical and physical processes in various fluorocarbon gases under the RIE mode have been investigated and the role of etching species such as fluorine, bromine, and oxygen is discussed.

  19. Selective neuronal cell attachment to a covalently patterned monoamine on fluorinated ethylene propylene films.

    Science.gov (United States)

    Ranieri, J P; Bellamkonda, R; Jacob, J; Vargo, T G; Gardella, J A; Aebischer, P

    1993-07-01

    The patterned covalent surface addition of a monoamine to fluorinated ethylene propylene films (FEP) controls both cellular attachment and differentiation in defined media conditions. A radio frequency glow discharge (RFGD) process was used to replace FEP surface fluorine atoms with hydroxyl groups. The primary amine was then covalently attached by polymerizing aminopropyl-triethoxysilane (APTES) via the hydroxyl functionalities. The selective attachment of cells to the APTES regions was determined to be dependent upon the initial adsorption of albumin to the patterned FEP membrane. Albumin was determined to enhance cellular attachment to the APTES regions and prevent attachment to the unmodified FEP areas for both an NB2a neuroblastoma cell line and primary rat endothelial cells. If albumin were not preadsorbed onto the membrane, selective attachment to the modified regions would not occur. Radiolabeling albumin with 125I demonstrated the preference of albumin for adsorption onto the monoamine surface where the cells preferentially attached. Both hydrophobic and ionic forces contributed to the adsorption process. Although selective cellular attachment to the patterned APTES regions could be achieved by albumin preadsorption to the surface, the neuroblastoma cells did not significantly differentiate unless additional serum components were supplemented to the media.

  20. An Eco-Friendly Ultrasound-Assisted Synthesis of Novel Fluorinated Pyridinium Salts-Based Hydrazones and Antimicrobial and Antitumor Screening

    Directory of Open Access Journals (Sweden)

    Nadjet Rezki

    2016-05-01

    Full Text Available The present work reports an efficient synthesis of fluorinated pyridinium salts-based hydrazones under both conventional and eco-friendly ultrasound procedures. The synthetic approach first involves the preparation of halogenated pyridinium salts through the condensation of isonicotinic acid hydrazide (1 with p-fluorobenzaldehyde (2 followed by the nucleophilic alkylation of the resulting N-(4-fluorobenzylideneisonicotinohydrazide (3 with a different alkyl iodide. The iodide counteranion of 5–10 was subjected to an anion exchange metathesis reaction in the presence of an excess of the appropriate metal salts to afford a new series of fluorinated pyridinium salts tethering a hydrazone linkage 11–40. Ultrasound irradiation led to higher yields in considerably less time than the conventional methods. The newly synthesized ILs were well-characterized with FT-IR, 1H NMR, 13C NMR, 11B, 19F, 31P and mass spectral analyses. The ILs were also screened for their antimicrobial and antitumor activities. Within the series, the salts tethering fluorinated counter anions 11–13, 21–23, 31–33 and 36–38 were found to be more potent against all bacterial and fungal strains at MIC 4–8 µg/mL. The in vitro antiproliferative activity was also investigated against four tumor cell lines (human ductal breast epithelial tumor T47D, human breast adenocarcinoma MCF-7, human epithelial carcinoma HeLa and human epithelial colorectal adenocarcinoma Caco-2 using the MTT assay, which revealed that promising antitumor activity was exhibited by compounds 5, 12 and 14.

  1. Selective reactive ion etching of tungsten films in fluorinated gases. Technical report

    Energy Technology Data Exchange (ETDEWEB)

    Pan, W.S.; Steckl, A.J.

    1987-07-01

    The use of reactive ion etching (RIE) with fluorinated gas plasmas, such as SF/sub 6/, CHF/sub 3/ and CF/sub 4/ mixed with oxygen, to achieve selective patterning of tungsten films is reported. Rapid thermal annealing (RTA) was used to improve the properties of sputtered films. The resistivity of W films was found to decrease rapidly with annealing time (within 10 sec) and to exhibit an Arrhenius behaviour with annealing temperature. The etch rates of W, Si, and SiO/sub 2/ were measured as a function of oxygen percentage in the fluorinated gas plasma. The results on optimum selectivity indicate that a CHF/sub 3//70%O mixture results in W:Si and W:SiO/sub 2/ etch rate ratios of 2.4:1 and 2.1:1 for unannealed W films, and 1.6:1 and 1.8:1 for annealed samples, respectively. A higher W etch rate selectivity over SiO/sub 2/ was obtained in an SF/sub 6// 5% O/sub 2/ plasma where the etch rate ratio is 11.6:1 for unannealed W films and 3:1 for annealed W samples. For reverse selectivity, the optimum W:SiO/sub 2/ etch rate ratios measured are 1:7.7 in pure CHF/sub 3/ gas for unannealed W and 1:4.6 for annealed W. The optimum W:Si reverse selectivity of 1:10 is obtained with an SF/sub 6//30%O/sub 2/ mixture plasma for both annealed and unannealed films. Satisfactory anisotropic edge profiles were obtained with CHF/sub 3/ /70%O/sub 2/ and SF/sub 6//5%O/sub 2/ where vertical-to-later etch ratios of 3.5:1 and 2:1 were measured.

  2. New experiences on the time required for the appearance of fluoric cachexia in the guinea pig following ingestion of various fluorine salts

    Energy Technology Data Exchange (ETDEWEB)

    Cristiani, H.; Chausse, P.

    1926-01-01

    Experiments were performed to compare the time it took guinea pigs to develop cachexia after being given sodium fluosilicate or sodium fluoride. Results indicate that a dose-response relationship existed following the ingestion of the fluorine salts in relation to the time it took to produce cachexia. In addition, sodium fluosilicate was found to be more toxic than sodium fluoride. In guinea pigs which were given approximately 1/30 to 1/36 of the lethal dose, cachexia was produced from 44 to 70 days later. In guinea pigs given even smaller doses, cachexia did not appear for one to two years.

  3. Continuous gas/liquid–liquid/liquid flow synthesis of 4-fluoropyrazole derivatives by selective direct fluorination

    Directory of Open Access Journals (Sweden)

    Jessica R. Breen

    2011-08-01

    Full Text Available 4-Fluoropyrazole systems may be prepared by a single, sequential telescoped two-step continuous gas/liquid–liquid/liquid flow process from diketone, fluorine gas and hydrazine starting materials.

  4. A Gel-Polymer Sn-C/LiMn0.5Fe0.5PO4 Battery Using a Fluorine-Free Salt.

    Science.gov (United States)

    Di Lecce, Daniele; Fasciani, Chiara; Scrosati, Bruno; Hassoun, Jusef

    2015-09-30

    Safety and environmental issues, because of the contemporary use of common liquid electrolytes, fluorinated salts, and LiCoO2-based cathodes in commercial Li-ion batteries, might be efficiently mitigated by employing alternative gel-polymer battery configurations and new electrode materials. Herein we study a lithium-ion polymer cell formed by combining a LiMn0.5Fe0.5PO4 olivine cathode, prepared by simple solvothermal pathway, a nanostructured Sn-C anode, and a LiBOB-containing PVdF-based gel electrolyte. The polymer electrolyte, here analyzed in terms of electrochemical stability by impedance spectroscopy (EIS) and voltammetry, reveals full compatibility for cell application. The LiBOB electrolyte salt and the electrochemically delithiaded Mn0.5Fe0.5PO4 have a higher thermal stability compared to conventional LiPF6 and Li0.5CoO2, as confirmed by thermogravimetric analysis (TGA) and by galvanostatic cycling at high temperature. LiMn0.5Fe0.5PO4 and Sn-C, showing in lithium half-cell a capacity of about 120 and 350 mAh g(-1), respectively, within the gelled electrolyte configuration are combined in a full Li-ion polymer battery delivering a stable capacity of about 110 mAh g(-1), with working voltage ranging from 2.8 to 3.6 V.

  5. Salt Effect Accelerates Site-Selective Cysteine Bioconjugation

    Science.gov (United States)

    2016-01-01

    Highly efficient and selective chemical reactions are desired. For small molecule chemistry, the reaction rate can be varied by changing the concentration, temperature, and solvent used. In contrast for large biomolecules, the reaction rate is difficult to modify by adjusting these variables because stringent biocompatible reaction conditions are required. Here we show that adding salts can change the rate constant over 4 orders of magnitude for an arylation bioconjugation reaction between a cysteine residue within a four-residue sequence (π-clamp) and a perfluoroaryl electrophile. Biocompatible ammonium sulfate significantly enhances the reaction rate without influencing the site-specificity of π-clamp mediated arylation, enabling the fast synthesis of two site-specific antibody–drug conjugates that selectively kill HER2-positive breast cancer cells. Computational and structure–reactivity studies indicate that salts may tune the reaction rate through modulating the interactions between the π-clamp hydrophobic side chains and the electrophile. On the basis of this understanding, the salt effect is extended to other bioconjugation chemistry, and a new regioselective alkylation reaction at π-clamp cysteine is developed. PMID:27725962

  6. Electrolytes including fluorinated solvents for use in electrochemical cells

    Science.gov (United States)

    Tikhonov, Konstantin; Yip, Ka Ki; Lin, Tzu-Yuan

    2015-07-07

    Provided are electrochemical cells and electrolytes used to build such cells. The electrolytes include ion-supplying salts and fluorinated solvents capable of maintaining single phase solutions with the salts at between about -30.degree. C. to about 80.degree. C. The fluorinated solvents, such as fluorinated carbonates, fluorinated esters, and fluorinated esters, are less flammable than their non-fluorinated counterparts and increase safety characteristics of cells containing these solvents. The amount of fluorinated solvents in electrolytes may be between about 30% and 80% by weight not accounting weight of the salts. Fluorinated salts, such as fluoroalkyl-substituted LiPF.sub.6, fluoroalkyl-substituted LiBF.sub.4 salts, linear and cyclic imide salts as well as methide salts including fluorinated alkyl groups, may be used due to their solubility in the fluorinated solvents. In some embodiments, the electrolyte may also include a flame retardant, such as a phosphazene or, more specifically, a cyclic phosphazene and/or one or more ionic liquids.

  7. Selective Adsorption on Fluorinated Plastic Enables the Optical Detection of Molecular Pollutants in Water

    Science.gov (United States)

    Lanfranco, R.; Giavazzi, F.; Salina, M.; Tagliabue, G.; Di Nicolò, E.; Bellini, T.; Buscaglia, M.

    2016-05-01

    Amorphous fluorinated plastic can be produced with a refractive index similar to that of water, a condition that makes it essentially invisible when immersed in aqueous solutions. Because of this property, even a small amount of adsorbed molecules on the plastic-water interface provides a detectable optical signal. We investigate two distinct substrates made of this material, characterized by different interface areas: a prism and a microporous membrane. We demonstrate that both substrates enable the label-free detection of molecular compounds in water even without any surface functionalization. The adsorption of molecules on the planar surface of the prism provides an increase of optical reflectivity, whereas the adsorption on the internal surface of the microporous membrane yields an increase of scattered light. Despite the different mechanisms, we find a similar optical response upon adsorption. We confirm this result by a theoretical model accounting for both reflection and scattering. We investigate the spontaneous adsorption process for different kinds of molecules: surfactants with different charges, a protein (lysozyme), and a constituent of gasoline (hexane). The measured equilibrium and kinetic constants for adsorption differ by orders of magnitudes among the different classes of molecules. By suitable analytical models, accounting for the effects of mass limitation and transport, we find a simple and general scaling of the adsorption parameters with the molecular size.

  8. Fluorine Generator

    Science.gov (United States)

    1975-04-02

    J^—i^.^/.^.^^;. ma* ^m^*^*ml*mm^mmm’**m*, • ww "-rrm-^r- The significant product, arsenic trifluoride (AsF ), was available in...fluorine, "F, from equilibrium adiabatic combustion (Table V) included a contribution when dissociation of the major product chlorine monofluoride, GIF...heat loss. The combustion product, arsenic trifluoride , is predicted to remain a vapor. The combustion product, potassium fluoride (KF), is

  9. FLUORINATION PROCESS

    Science.gov (United States)

    McMillan, T.S.

    1957-10-29

    A process for the fluorination of uranium metal is described. It is known that uranium will react with liquid chlorine trifluoride but the reaction proceeds at a slow rate. However, a mixture of a halogen trifluoride together with hydrogen fluoride reacts with uranium at a significantly faster rate than does a halogen trifluoride alone. Bromine trifluoride is suitable for use in the process, but chlorine trifluoride is preferred. Particularly suitable is a mixture of ClF/sub 3/ and HF having a mole ratio (moles

  10. Synthesis of a Fluorine-Containing Cis-Cisoidal One-Handed Helical Polyphenylacetylene and Application of Highly Selective Photocyclic Aromatization Product on Oxygen Permselective Membrane.

    Science.gov (United States)

    Zang, Yu; Yin, Guanwu; Aoki, Toshiki; Teraguchi, Masahiro; Kaneko, Takashi; Ma, Liqun; Jia, Hongge

    2015-08-01

    A novel phenylacetylene monomer having a perfluorinated alkyl group (M-F) was synthesized and polymerized in a chiral catalytic system to yield a one-handed helical polymer. The ability and efficiency of the chiral induction of the fluorine-containing monomer in the helix-sense-selective polymerization (HSSP) was much higher than those of a monomer having the corresponding alkyl group (M-H) we reported before. The resulting polymer showed cis-cisoidal one-handed helical conformation, and was suitable for highly selective photocyclic aromatization (SCAT) to give a 2D surface modifier (). Oxygen permselectivity through a base polymer membrane was highly enhanced from 1.83 to 2.36 by adding a small amount (1-5 wt%) of the 2D surface modifier . The improvement was thought to be caused by improvement of solution selectivity on the membrane surface which the 2D surface modifier effectively covered. © 2015 Wiley Periodicals, Inc.

  11. Fluorination of some highly functionalized cycloalkanes: chemoselectivity and substrate dependence

    Directory of Open Access Journals (Sweden)

    Attila Márió Remete

    2017-11-01

    Full Text Available A study exploring the chemical behavior of some dihydroxylated β-amino ester stereo- and regioisomers, derived from unsaturated cyclic β-amino acids is described. The nucleophilic fluorinations involving hydroxy–fluorine exchange of some highly functionalized alicyclic diol derivatives have been carried out in view of selective fluorination, investigating substrate dependence, neighboring group assistance and chemodifferentiation.

  12. Removal of fluorine from and introduction of fluorine into polyhalopyridines: an exercise in nucleophilic hetarenic substitution.

    Science.gov (United States)

    Bobbio, Carla; Rausis, Thierry; Schlosser, Manfred

    2005-03-04

    Starting from six industrially available fluorinated pyridines, an expedient access to all three tetrafluoropyridines (2-4), all six trifluoropyridines (5-10), and the five non-commercial difluoropyridines (11-14 and 16) was developed. The methods employed for the selective removal of fluorine from polyfluoropyridines were the reduction by metals or complex hydrides and the site-selective replacement by hydrazine followed by dehydrogenation-dediazotation or dehydrochlorination-dediazotation. To introduce an extra fluorine atom, a suitable precursor was metalated and chlorinated before being subjected to a chlorine/fluorine displacement process.

  13. Selective Functionalization of Pyridines via Heterocyclic Phosphonium Salts.

    Science.gov (United States)

    Hilton, Michael C; Dolewski, Ryan D; McNally, Andrew

    2016-10-12

    Methods that directly functionalize pyridines are in high demand due to their presence in pharmaceuticals, agrochemicals and materials. A reaction that selectively transforms the 4-position C-H bonds in pyridines into C-PPh3+ groups that are subsequently converted into heteroaryl ethers is presented. The two step sequence is effective on complex pyridines, pharmaceutical molecules and other classes of heterocycles. Initial studies show that C-C, C-N and C-S bond formations are also amenable.

  14. Selective Adsorption of Sodium Aluminum Fluoride Salts from Molten Aluminum

    Energy Technology Data Exchange (ETDEWEB)

    Leonard S. Aubrey; Christine A. Boyle; Eddie M. Williams; David H. DeYoung; Dawid D. Smith; Feng Chi

    2007-08-16

    Aluminum is produced in electrolytic reduction cells where alumina feedstock is dissolved in molten cryolite (sodium aluminum fluoride) along with aluminum and calcium fluorides. The dissolved alumina is then reduced by electrolysis and the molten aluminum separates to the bottom of the cell. The reduction cell is periodically tapped to remove the molten aluminum. During the tapping process, some of the molten electrolyte (commonly referred as “bath” in the aluminum industry) is carried over with the molten aluminum and into the transfer crucible. The carryover of molten bath into the holding furnace can create significant operational problems in aluminum cast houses. Bath carryover can result in several problems. The most troublesome problem is sodium and calcium pickup in magnesium-bearing alloys. Magnesium alloying additions can result in Mg-Na and Mg-Ca exchange reactions with the molten bath, which results in the undesirable pickup of elemental sodium and calcium. This final report presents the findings of a project to evaluate removal of molten bath using a new and novel micro-porous filter media. The theory of selective adsorption or removal is based on interfacial surface energy differences of molten aluminum and bath on the micro-porous filter structure. This report describes the theory of the selective adsorption-filtration process, the development of suitable micro-porous filter media, and the operational results obtained with a micro-porous bed filtration system. The micro-porous filter media was found to very effectively remove molten sodium aluminum fluoride bath by the selective adsorption-filtration mechanism.

  15. Super-hydrophobic fluorine containing aerogels

    Science.gov (United States)

    Coronado, Paul R [Livermore, CA; Poco, John F [Livermore, CA; Hrubesh, Lawrence W [Pleasanton, CA

    2007-05-01

    An aerogel material with surfaces containing fluorine atoms which exhibits exceptional hydrophobicity, or the ability to repel liquid water. Hydrophobic aerogels are efficient absorbers of solvents from water. Solvents miscible with water are separated from it because the solvents are more volatile than water and they enter the porous aerogel as a vapor across the liquid water/solid interface. Solvents that are immisicble with water are separated from it by selectively wetting the aerogel. The hydrophobic property is achieved by formulating the aerogel using fluorine containing molecules either directly by addition in the sol-gel process, or by treating a standard dried aerogel using the vapor of fluorine containing molecules.

  16. Microsatellite signature of ecological selection for salt tolerance in a wild sunflower hybrid species, Helianthus paradoxus

    Science.gov (United States)

    EDELIST, CÉCILE; LEXER, CHRISTIAN; DILLMANN, CHRISTINE; SICARD, DELPHINE; RIESEBERG, LOREN H.

    2008-01-01

    The hybrid sunflower species Helianthus paradoxus inhabits sporadic salt marshes in New Mexico and southwest Texas, USA, whereas its parental species, Helianthus annuus and Helianthus petiolaris, are salt sensitive. Previous studies identified three genomic regions — survivorship quantitative trait loci (QTLs) — that were under strong selection in experimental hybrids transplanted into the natural habitat of H. paradoxus. Here we ask whether these same genomic regions experienced significant selection during the origin and evolution of the natural hybrid, H. paradoxus. This was accomplished by comparing the variability of microsatellites linked to the three survivorship QTLs with those from genomic regions that were neutral in the experimental hybrids. As predicted if one or more selective sweeps had occurred in these regions, microsatellites linked to the survivorship QTLs exhibited a significant reduction in diversity in populations of the natural hybrid species. In contrast, no difference in diversity levels was observed between the two microsatellite classes in parental populations. PMID:17107488

  17. Habitat selection by Forster's Terns (Sterna forsteri) at multiple spatial scales in an urbanized estuary: The importance of salt ponds

    Science.gov (United States)

    Bluso-Demers, Jill; Ackerman, Joshua T.; Takekawa, John Y.; Peterson, Sarah

    2016-01-01

    The highly urbanized San Francisco Bay Estuary, California, USA, is currently undergoing large-scale habitat restoration, and several thousand hectares of former salt evaporation ponds are being converted to tidal marsh. To identify potential effects of this habitat restoration on breeding waterbirds, habitat selection of radiotagged Forster's Terns (Sterna forsteri) was examined at multiple spatial scales during the pre-breeding and breeding seasons of 2005 and 2006. At each spatial scale, habitat selection ratios were calculated by season, year, and sex. Forster's Terns selected salt pond habitats at most spatial scales and demonstrated the importance of salt ponds for foraging and roosting. Salinity influenced the types of salt pond habitats that were selected. Specifically, Forster's Terns strongly selected lower salinity salt ponds (0.5–30 g/L) and generally avoided higher salinity salt ponds (≥31 g/L). Forster's Terns typically used tidal marsh and managed marsh habitats in proportion to their availability, avoided upland and tidal flat habitats, and strongly avoided open bay habitats. Salt ponds provide important habitat for breeding waterbirds, and restoration efforts to convert former salt ponds to tidal marsh may reduce the availability of preferred breeding and foraging areas.

  18. Catalytic asymmetric fluorinations.

    Science.gov (United States)

    Bobbio, Carla; Gouverneur, Véronique

    2006-06-07

    The appearance of structurally diverse fluorinating reagents displaying a large spectrum of reactivity has been critical to the development of the catalytic asymmetric fluorination processes known to date. In this article, we discuss how this area of research emerged and which strategies have allowed for the successful development of both nucleophilic and electrophilic catalytic enantioselective fluorinations. We also present the fundamental understanding of catalytic activity and enantioselectivity for the most efficient processes and highlight the first synthetic application with the preparation of a complex fluorinated target.

  19. Regulatory monitoring systems of fortified salt and wheat flour in selected ASEAN countries.

    Science.gov (United States)

    van den Wijngaart, Annoek; Bégin, France; Codling, Karen; Randall, Philip; Johnson, Quentin W

    2013-06-01

    Considerable efforts have been made over the past decade to address vitamin and mineral deficiencies. An increasing number of countries in the Association of Southeast Asian Nations (ASEAN) are adopting mandatory food fortification as one of the primary strategies to overcome these deficiencies. Experience shows that fortified foods can reach large parts of the population, including the poor, if the fortification is done on a mandatory rather than a voluntary basis and if the food vehicle is widely consumed. To review the importance of regulatory monitoring as an essential component of food fortification efforts in selected ASEAN countries, with special focus on the available information on regulatory monitoring systems for iodized salt and fortified wheat flour. The role of regulatory monitoring in strengthening food fortification programs was discussed during a joint regional meeting of the World Health Organization, UNICEF, the Flour Fortification Initiative, the Global Alliance for Improved Nutrition, the Micronutrient Initiative, and the World Bank on regulatory monitoring of salt and wheat flour fortification programs in Asia, which took place in Manila, Philippines, on 27-29 September 2011. This paper reviews the regulatory monitoring systems of selected ASEAN countries that participated in this meeting. Problems and challenges in regulatory monitoring systems for iodized salt and fortified wheat flour in selected ASEAN countries are identified, and a description of the role of regulatory monitoring in strengthening food fortification initiatives, particularly of salt and flour, and highlights of areas for improvement are presented. Regulatory monitoring consists of monitoring activities conducted at the production level, at customs warehouses, and at retail stores by concerned regulatory authorities, and at the production level by producers themselves, as part of quality control and assurance efforts. Unless there are appropriate enforcement and quality

  20. Selection and durability of seal materials for a bedded salt repository: preliminary studies

    Energy Technology Data Exchange (ETDEWEB)

    Roy, D.M.; Grutzeck, M.W.; Wakeley, L.D.

    1983-11-01

    This report details preliminary results of both experimental and theoretical studies of cementitious seal materials for use in a proposed nuclear waste repository in bedded salt. Effects of changes in bulk composition and environment upon phase stability and physical/mechanical properties have been evaluated for more than 25 formulations. Bonding and interfacial characteristics of the region between host rock and seal material or concrete aggregate and cementitious matrix for selected formulations have been studied. Compatibilities of clays and zeolites in brines typical of the SE New Mexico region have been investigated, and their stabilities reviewed. Results of these studies have led to the conclusion that cementitious materials can be formulated which are compatible with the major rock types in a bedded salt repository environment. Strengths are more than adequate, permeabilities are consistently very low, and elastic moduli generally increase only very slightly with time. Seal formulation guidelines and recommendations for present and future work are presented. 73 references, 25 figures, 61 tables.

  1. Facile nucleophilic fluorination reactions using tert-alcohols as a reaction medium: significantly enhanced reactivity of alkali metal fluorides and improved selectivity.

    Science.gov (United States)

    Kim, Dong Wook; Jeong, Hwan-Jeong; Lim, Seok Tae; Sohn, Myung-Hee; Katzenellenbogen, John A; Chi, Dae Yoon

    2008-02-01

    Although protic solvents are generally not preferred for nucleophilic displacement reactions because of their partial positive charge and hydrogen-bonding capacity that solvate the nucleophile and reduce its reactivity, we recently reported a remarkably beneficial effect of using tertiary alcohols as a reaction media for nucleophilic fluorination with alkali metal fluorides, as well as fluorine-18 radiolabeling with [18F]fluoride ion for the preparation of PET radiopharmaceuticals. In this work, we investigate further the influence of the tert-alcohol reaction medium for nucleophilic fluorination with alkali metal fluorides by studying various interactions among tert-alcohols, the alkali metal fluoride (CsF), and the sulfonyloxy substrate. Factors such as hydrogen bonding between CsF and the tert-alcohol solvent, the formation of a tert-alcohol solvated fluoride, and hydrogen bonding between the sulfonate leaving group and the tert-alcohol appear to contribute to the dramatic increase in the rate of the nucleophilic fluorination reaction in the absence of any kind of catalyst. We found that fluorination of 1-(2-mesyloxyethyl)naphthalene (5) and N-5-bromopentanoyl-3,4-dimethoxyaniline (8) with Bu(4)N(+)F(-) in a tert-alcohol afforded the corresponding fluoro products in much higher yield than obtained by the conventional methods using dipolar aprotic solvents. The protic medium also suppresses formation of byproducts, such as alkenes, ethers, and cyclic adducts.

  2. A convenient chemical-microbial method for developing fluorinated pharmaceuticals.

    Science.gov (United States)

    Bright, Tara V; Dalton, Fay; Elder, Victoria L; Murphy, Cormac D; O'Connor, Neil K; Sandford, Graham

    2013-02-21

    A significant proportion of pharmaceuticals are fluorinated and selecting the site of fluorine incorporation can be an important beneficial part a drug development process. Here we describe initial experiments aimed at the development of a general method of selecting optimum sites on pro-drug molecules for fluorination, so that metabolic stability may be improved. Several model biphenyl derivatives were transformed by the fungus Cunninghamella elegans and the bacterium Streptomyces griseus, both of which contain cytochromes P450 that mimic oxidation processes in vivo, so that the site of oxidation could be determined. Subsequently, fluorinated biphenyl derivatives were synthesised using appropriate Suzuki-Miyaura coupling reactions, positioning the fluorine atom at the pre-determined site of microbial oxidation; the fluorinated biphenyl derivatives were incubated with the microorganisms and the degree of oxidation assessed. Biphenyl-4-carboxylic acid was transformed completely to 4'-hydroxybiphenyl-4-carboxylic acid by C. elegans but, in contrast, the 4'-fluoro-analogue remained untransformed exemplifying the microbial oxidation - chemical fluorination concept. 2'-Fluoro- and 3'-fluoro-biphenyl-4-carboxylic acid were also transformed, but more slowly than the non-fluorinated biphenyl carboxylic acid derivative. Thus, it is possible to design compounds in an iterative fashion with a longer metabolic half-life by identifying the sites that are most easily oxidised by in vitro methods and subsequent fluorination without recourse to extensive animal studies.

  3. [Selection and identification of salt tolerant line of sainfoin from the seeds of first post-flight plants].

    Science.gov (United States)

    Xu, Y Y; Wang, M G; Jia, J F

    2001-03-01

    Seeds of sainfoin (Onobrychis vicaefolia Scop.) were carried in the recoverable satellite 940703 and recovered from earth orbit from China in 1994. The progeny seeds were obtained by producing in field. The salt tolerant calluses were selected by screening seedling and callus on 1.5% NaCl-containing medium, reviving growth on NaCl- free medium and selecting callus on 1.2% NaCl-containing medium. The salt tolerant line callus maintained the normal ability to regenerate plant. The salt tolerant line callus exhibited cross-resistance to PEG stress. The variant appeared higher efficiency than control to accumulate proline under salt stress, however, under nonstress condition it had lower proline level than control, which suggested that the higher efficiency to synthesize proline under stress condition may be more important than higher level in tissue under nonstress condition. The mechanism of proline synthesis in the selected callus was considered to result from the alteration in gene sensitivity to water regulation at transcription level. Acrylamide gradient electrophoresis showed that new isoenzyme form with MW 175 kD and 75 kD of superoxide dismutase and esterase respectively appeared in salt torlerant callus. It was indicated that the combination of space mutagenesis with tissue culture could be used for the selection of salt tolerant sainfoin line in vitro.

  4. [Fluorine-18 in radiopharmacy].

    Science.gov (United States)

    de Beco, V; Le Bars, D; Scherrmann, J-M

    2008-01-01

    Positron emission tomography (PET) is a recent and expanding functional nuclear imaging technique. Its extensive development is related to the radiophysical properties fluorine 18 (18F) (weak energy of positron, sufficiently long physical half-life) and to the simple production and labeling procedures for 18F. [18F]fluorodesoxyglucose was the first licensed radiopharmaceutical in France in 1998. [18F]fluoroDOPA was registered in 2006. Introduction of automated chemistry modules enable development of new fluorinated tracers.

  5. Improving Photoconductance of Fluorinated Donors with Fluorinated Acceptors

    Energy Technology Data Exchange (ETDEWEB)

    Garner, Logan E.; Larson, Bryon; Oosterhout, Stefan; Owczarczyk, Zbyslaw; Olson, Dana C.; Kopidakis, Nikos; Boltalina, Olga V.; Strauss, Steven H.; Braunecker, Wade A.

    2016-11-21

    This work investigates the influence of fluorination of both donor and acceptor materials on the generation of free charge carriers in small molecule donor/fullerene acceptor BHJ OPV active layers. A fluorinated and non-fluorinated small molecule analogue were synthesized and their optoelectronic properties characterized. The intrinsic photoconductance of blends of these small molecule donors was investigated using time-resolved microwave conductivity. Blends of the two donor molecules with a traditional non-fluorinated fullerene (PC70BM) as well as a fluorinated fullerene (C60(CF3)2-1) were investigated using 5% and 50% fullerene loading. We demonstrate for the first time that photoconductance in a 50:50 donor:acceptor BHJ blend using a fluorinated fullerene can actually be improved relative to a traditional non-fluorinated fullerene by fluorinating the donor molecule as well.

  6. Fluorine in psychedelic phenethylamines.

    Science.gov (United States)

    Trachsel, Daniel

    2012-01-01

    The so-called psychedelic phenethylamines represent a class of drugs with a large range of psychoactive properties in humans, ranging from naturally occurring mescaline to amphetamine analogues and homologues. The interest in many of these compounds, occasionally referred to as designer-drugs, is widely dispersed across popular culture and political and scientific communities. In recent decades, fluorine has become a powerful and important tool in medicinal chemistry. In addition, fluorine-containing compounds and medicines can be found in numerous commercially successful pharmaceuticals that have gained a market share of some 5-15%. One might anticipate this trend to increase in the future. As far as fluorinated phenethylamines are concerned, much less is known about their chemistry and pharmacology. This paper provides an overview regarding the biological properties of over 60 fluorinated phenethylamines and discusses both historical and recent chemistry-related developments. It was shown that the introduction of fluorine into the phenethylamine nucleus can impact greatly on psychoactivity of these compounds, ranging from marked loss to enhancement and prolongation of effects. For example, in contrast to the psychoactive escaline (70), it was observed that its fluoroescaline (76) counterpart was almost devoid of psychoactive effects. Difluoroescaline (77), on the other hand, retained, and trifluoroescaline (78) showed increased human potency of escaline (70). Difluoromescaline (72) and trifluoromescaline (73) increasingly surpassed human potency and duration of mescaline (22) effects. Copyright © 2012 John Wiley & Sons, Ltd.

  7. Contribution of selected perfluoroalkyl and polyfluoroalkyl substances to the adsorbable organically bound fluorine in German rivers and in a highly contaminated groundwater.

    Science.gov (United States)

    Willach, Sarah; Brauch, Heinz-Jürgen; Lange, Frank T

    2016-02-01

    Due to the lack of analytical standards the application of surrogate parameters for organofluorine detection in the aquatic environment is a complementary approach to single compound target analysis of perfluoroalkyl and polyfluoroalkyl chemicals (PFASs). The recently developed method adsorbable organically bound fluorine (AOF) is based on adsorption of organofluorine chemicals to activated carbon followed by combustion ion chromatography. This AOF method was further simplified to enable measurement of larger series of environmental samples. The limit of quantification (LOQ) was 0.77 μg/L F. The modified protocol was applied to 22 samples from German rivers, a municipal wastewater treatment plant (WWTP) effluent, and four groundwater samples from a fire-fighting training site. The WWTP effluent (AOF = 1.98 μg/L F) and only three river water samples (AOF between 0.88 μg/L F and 1.47 μg/L F) exceeded the LOQ. The AOF levels in a PFASs plume at a heavily contaminated site were in the range of 162 ± 3 μg/L F to 782 ± 43 μg/L F. In addition to AOF 17 PFASs were analyzed by high performance liquid chromatography-tandem mass spectrometry. 32-51% of AOF in the contaminated groundwater samples were explained by individual PFASs wheras in the surface waters more than 95% remained unknown. Organofluorine of two fluorinated pesticides, one pesticide metabolite and three fluorinated pharmaceuticals was recovered as AOF by >50% from all four tested water matrices. It is suggested that in the diffusely contaminated water bodies such fluorinated chemicals and not monitored PFASs contribute significantly to AOF. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Fluorine-18 labelled building blocks for PET tracer synthesis.

    Science.gov (United States)

    van der Born, Dion; Pees, Anna; Poot, Alex J; Orru, Romano V A; Windhorst, Albert D; Vugts, Danielle J

    2017-07-31

    Positron emission tomography (PET) is an important driver for present day healthcare. Fluorine-18 is the most widely used radioisotope for PET imaging and a thorough overview of the available radiochemistry methodology is a prerequisite for selection of a synthetic approach for new fluorine-18 labelled PET tracers. These PET tracers can be synthesised either by late-stage radiofluorination, introducing fluorine-18 in the last step of the synthesis, or by a building block approach (also called modular build-up approach), introducing fluorine-18 in a fast and efficient manner in a building block, which is reacted further in one or multiple reaction steps to form the PET tracer. This review presents a comprehensive overview of the synthesis and application of fluorine-18 labelled building blocks since 2010.

  9. Fluorine-rich planetary environments as possible habitats for life.

    Science.gov (United States)

    Budisa, Nediljko; Kubyshkin, Vladimir; Schulze-Makuch, Dirk

    2014-08-18

    In polar aprotic organic solvents, fluorine might be an element of choice for life that uses selected fluorinated building blocks as monomers of choice for self-assembling of its catalytic polymers. Organofluorine compounds are extremely rare in the chemistry of life as we know it. Biomolecules, when fluorinated such as peptides or proteins, exhibit a "fluorous effect", i.e., they are fluorophilic (neither hydrophilic nor lipophilic). Such polymers, capable of creating self-sorting assemblies, resist denaturation by organic solvents by exclusion of fluorocarbon side chains from the organic phase. Fluorous cores consist of a compact interior, which is shielded from the surrounding solvent. Thus, we can anticipate that fluorine-containing "teflon"-like or "non-sticking" building blocks might be monomers of choice for the synthesis of organized polymeric structures in fluorine-rich planetary environments. Although no fluorine-rich planetary environment is known, theoretical considerations might help us to define chemistries that might support life in such environments. For example, one scenario is that all molecular oxygen may be used up by oxidation reactions on a planetary surface and fluorine gas could be released from F-rich magma later in the history of a planetary body to result in a fluorine-rich planetary environment.

  10. Fluorine-Rich Planetary Environments as Possible Habitats for Life

    Directory of Open Access Journals (Sweden)

    Nediljko Budisa

    2014-08-01

    Full Text Available In polar aprotic organic solvents, fluorine might be an element of choice for life that uses selected fluorinated building blocks as monomers of choice for self-assembling of its catalytic polymers. Organofluorine compounds are extremely rare in the chemistry of life as we know it. Biomolecules, when fluorinated such as peptides or proteins, exhibit a “fluorous effect”, i.e., they are fluorophilic (neither hydrophilic nor lipophilic. Such polymers, capable of creating self-sorting assemblies, resist denaturation by organic solvents by exclusion of fluorocarbon side chains from the organic phase. Fluorous cores consist of a compact interior, which is shielded from the surrounding solvent. Thus, we can anticipate that fluorine-containing “teflon”-like or “non-sticking” building blocks might be monomers of choice for the synthesis of organized polymeric structures in fluorine-rich planetary environments. Although no fluorine-rich planetary environment is known, theoretical considerations might help us to define chemistries that might support life in such environments. For example, one scenario is that all molecular oxygen may be used up by oxidation reactions on a planetary surface and fluorine gas could be released from F-rich magma later in the history of a planetary body to result in a fluorine-rich planetary environment.

  11. Selection of efficient salt-tolerant bacteria containing ACC deaminase for promotion of tomato growth under salinity stress

    Directory of Open Access Journals (Sweden)

    Kannika Chookietwattana* and Kedsukon Maneewan

    2012-05-01

    Full Text Available For successful application of plant growth promoting bacteria (PGPB in salt-affected soil, bioinoculant with salt-tolerant property is required in order to provide better survival and perform well in the field. The present study aimed to select the most efficient salt-tolerant bacterium containing 1-aminocyclopropane-1-carboxylic acid (ACC deaminase from eighty four bacterial strains and to investigate the effects of the selected bacterium on the germination and growth of tomato (Licopersicon esculentum Mill. cv. Seeda under saline conditions. The Bacillus licheniformis B2r was selected for its ability to utilize ACC as a sole nitrogen source under salinity stress. It also showed a high ACC deaminase activity at 0.6 M NaCl salinity. Tomato plants inoculated with the selected bacterium under various saline conditions (0, 30, 60, 90 and 120 mM NaCl revealed a significant increase in the germination percentage, germination index, root length, and seedling dry weight especially at salinity levels ranging from 30-90 mM NaCl. The work described in this report is an important step in developing an efficient salt-tolerant bioinoculant to facilitate plant growth in saline soil.

  12. Fluorine Based Superhydrophobic Coatings

    Directory of Open Access Journals (Sweden)

    Jean-Denis Brassard

    2012-05-01

    Full Text Available Superhydrophobic coatings, inspired by nature, are an emerging technology. These water repellent coatings can be used as solutions for corrosion, biofouling and even water and air drag reduction applications. In this work, synthesis of monodispersive silica nanoparticles of ~120 nm diameter has been realized via Stöber process and further functionalized using fluoroalkylsilane (FAS-17 molecules to incorporate the fluorinated groups with the silica nanoparticles in an ethanolic solution. The synthesized fluorinated silica nanoparticles have been spin coated on flat aluminum alloy, silicon and glass substrates. Functionalization of silica nanoparticles with fluorinated groups has been confirmed by Fourier Transform Infrared spectroscopy (FTIR by showing the presence of C-F and Si-O-Si bonds. The water contact angles and surface roughness increase with the number of spin-coated thin films layers. The critical size of ~119 nm renders aluminum surface superhydrophobic with three layers of coating using as-prepared nanoparticle suspended solution. On the other hand, seven layers are required for a 50 vol.% diluted solution to achieve superhydrophobicity. In both the cases, water contact angles were more than 150°, contact angle hysteresis was less than 2° having a critical roughness value of ~0.700 µm. The fluorinated silica nanoparticle coated surfaces are also transparent and can be used as paint additives to obtain transparent coatings.

  13. LITERATURE REVIEWS TO SUPPORT ION EXCHANGE TECHNOLOGY SELECTION FOR MODULAR SALT PROCESSING

    Energy Technology Data Exchange (ETDEWEB)

    King, W

    2007-11-30

    This report summarizes the results of literature reviews conducted to support the selection of a cesium removal technology for application in a small column ion exchange (SCIX) unit supported within a high level waste tank. SCIX is being considered as a technology for the treatment of radioactive salt solutions in order to accelerate closure of waste tanks at the Savannah River Site (SRS) as part of the Modular Salt Processing (MSP) technology development program. Two ion exchange materials, spherical Resorcinol-Formaldehyde (RF) and engineered Crystalline Silicotitanate (CST), are being considered for use within the SCIX unit. Both ion exchange materials have been studied extensively and are known to have high affinities for cesium ions in caustic tank waste supernates. RF is an elutable organic resin and CST is a non-elutable inorganic material. Waste treatment processes developed for the two technologies will differ with regard to solutions processed, secondary waste streams generated, optimum column size, and waste throughput. Pertinent references, anticipated processing sequences for utilization in waste treatment, gaps in the available data, and technical comparisons will be provided for the two ion exchange materials to assist in technology selection for SCIX. The engineered, granular form of CST (UOP IE-911) was the baseline ion exchange material used for the initial development and design of the SRS SCIX process (McCabe, 2005). To date, in-tank SCIX has not been implemented for treatment of radioactive waste solutions at SRS. Since initial development and consideration of SCIX for SRS waste treatment an alternative technology has been developed as part of the River Protection Project Waste Treatment Plant (RPP-WTP) Research and Technology program (Thorson, 2006). Spherical RF resin is the baseline media for cesium removal in the RPP-WTP, which was designed for the treatment of radioactive waste supernates and is currently under construction in Hanford, WA

  14. Enhancement mechanisms behind exclusive removal and selective recovery of copper from salt solutions with an aminothiazole-functionalized adsorbent

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Chao; Liu, Fu-qiang, E-mail: jogia@163.com; Gao, Jie; Li, Lan-juan; Bai, Zhi-ping, E-mail: baizp@nju.edu.cn; Ling, Chen; Zhu, Chang-qing; Chen, Da; Li, Ai-min

    2014-09-15

    Graphical abstract: - Highlights: • Exclusive removal and selective recovery of copper from salt solutions was achieved. • Interaction mechanisms and selective adsorption mechanisms were depicted. • Geometric structure of complex was optimized and affirmed by DFT. • Enhancement mechanism of salts was further investigated. - Abstract: The aminothiazole-functionalized adsorbent (CEAD) could exclusively remove and to selectively recover copper. The adsorption and separation properties of Cu(II) onto CEAD from aqueous media, with or without salts such as NaNO{sub 3}, Ca(NO{sub 3}){sub 2} and Ni(NO{sub 3}){sub 2}, were systematically compared by carrying out single, binary and multiple component static and dynamic experiments. In binary systems, the adsorption capacities of Cu(II) were obviously increased by 39.47%, 47.37% and 57.89% with Ni(NO{sub 3}){sub 2}, NaNO{sub 3} and Ca(NO{sub 3}){sub 2}, respectively. Besides, simulation study was performed to selectively recover Cu(II) from multi-component aqueous media, with the separation factor of only 54.91 in aqueous media without salts. The separation factor became infinite in the presence of NaNO{sub 3} and the enhancement ratio for Cu(II) was raised by 126.31%. Dynamic adsorption could separate Cu(II) and Ni(II) completely and the amount of effluent for pure Ni(II) increased to 127 BV with the help of NaNO{sub 3}. In the predominant chelating mode simulated by density functional theory calculation, a metal ion coordinated with three nitrogen atoms and formed a chelating complex with two five-membered rings, and Cu(II) showed stronger coordinating ability than Ni(II) did. Meanwhile, anions exerted significant beneficial effects by electrostatic screening, and thus strengthened the exclusive removal and selective recovery of Cu(II)

  15. Interactions between selected bile salts and Triton X-100 or sodium lauryl ether sulfate

    National Research Council Canada - National Science Library

    Ćirin, Dejan M; Poša, Mihalj M; Krstonošić, Veljko S

    2011-01-01

    .... Bile salt mixed micelles are extensively studied as novel drug delivery systems. The objective of the present investigation is to develop and characterize mixed micelles of nonionic (Triton X-100) or anionic...

  16. highly selective amino acid salt solutions as absorption liquid for CO(2) capture in gas-liquid membrane contactors.

    Science.gov (United States)

    Simons, Katja; Nijmeijer, Kitty; Mengers, Harro; Brilman, Wim; Wessling, Matthias

    2010-08-23

    The strong anthropogenic increase in the emission of CO(2) and the related environmental impact force the developments towards sustainability and carbon capture and storage (CCS). In the present work, we combine the high product yields and selectivities of CO(2) absorption processes with the advantages of membrane technology in a membrane contactor for the separation of CO(2) from CH(4) using amino acid salt solutions as competitive absorption liquid to alkanol amine solutions. Amino acids, such as sarcosine, have the same functionality as alkanol amines (e.g., monoethanolamine=MEA), but in contrast, they exhibit a better oxidative stability and resistance to degradation. In addition, they can be made nonvolatile by adding a salt functionality, which significantly reduces the liquid loss due to evaporation at elevated temperatures in the desorber. Membrane contactor experiments using CO(2)/CH(4) feed mixtures to evaluate the overall process performance, including a full absorption/desorption cycle show that even without a temperature difference between absorber and desorber, a CO(2)/CH(4) selectivity of over 70 can be easily achieved with the sarcosine salt solution as absorption liquid. This selectivity reaches values of 120 at a temperature difference between absorber and desorber of 35 degrees C, compared to a value of only 60 for MEA under the same conditions. Although CO(2) permeance values are somewhat lower than the values obtained for MEA, the results clearly show the potential of amino acid salt solutions as competitive absorption liquids for the energy efficient removal of CO(2). In addition, due to the low absorption of CH(4) in sarcosine compared to MEA, the loss of CH(4) is reduced and significantly higher CH(4) product yields can be obtained.

  17. Fluorinated Polyurethanes, Synthesis and Properties

    Directory of Open Access Journals (Sweden)

    Olga Smirnova

    2016-07-01

    Full Text Available Fluorinated polyurethanes with a glass transition temperature as low as −139 °C and a decomposition onset temperature of 247–330 °C were prepared by a reaction of fluorinated alcohols with aromatic and cycloaliphatic diisocyanates in solution or melt.

  18. Fluorinated Polyurethanes, Synthesis and Properties

    OpenAIRE

    Olga Smirnova; Alexey Glazkov; Alexander Yarosh; Alexey Sakharov

    2016-01-01

    Fluorinated polyurethanes with a glass transition temperature as low as −139 °C and a decomposition onset temperature of 247–330 °C were prepared by a reaction of fluorinated alcohols with aromatic and cycloaliphatic diisocyanates in solution or melt.

  19. Process for preparing fluorine-18

    Science.gov (United States)

    Winchell, Harry S.; Wells, Dale K.; Lamb, James F.; Beaudry, Samuel B.

    1976-09-21

    An improved process for preparation of fluorine-18 by a neon (deuteron, alpha particle) fluorine-18 nuclear reaction in a non-reactive enclosed reaction zone wherein a ultrapure product is recovered by heating the reaction zone to a high temperature and removing the product with an inert gas.

  20. [Exploration of demonstration and promotion experiment of fluorine fixation technology during coal burning].

    Science.gov (United States)

    Li, Shumin; Yue, Yinling; Ying, Bo; Zhu, Wenling; Zhao, Bingcheng

    2011-01-01

    To demonstrate and promote the fluorine-fixing technology of the coal burning on a calcium-based compound as the additive for briquettes made in the coal-burning fluorosis area, in order to evaluate the effects of fluorine-fixing and indoor air pollutants condition. The briquettes added calcium-based fluorine sorbent were used for heating and cooking. In the meantime, the figures on various components in briquettes and fluorine content in coal slag as well as concentrations of indoor air fluorides, sulfur dioxide and PM10 were calculated. On the basis of the coal burning fluorine-fixing pilot experiment, 100 households in Longli County, Guizhou Province were selected as the experimental group for coal burning fluorine-fixing demonstration and promotion. When the burning calcium-based fluorine-fixing bitumites were made into coalballs, the average fluorine-fixing ratios in demonstration and promotion were 77.26%. The average reduction ratios of indoor air pollutants, fluorides were 53.3% -73.8%, sulfur dioxide were 62.8% -91.1% and PM10 were 9.5% -41.4%. There were 10% increases in the cost of briquettes due to the addition of calcium-based fluorine sorbent in demonstration and promotion. The preparation process of calcium-based fluorine-fixing briquettes was simple and highly flammable and it was applicable to regions abundant in bitumite.

  1. Selective n,n-dimethylation of primary aromatic amines with methyl alkyl carbonates in the presence of phosphonium salts.

    Science.gov (United States)

    Selva, Maurizio; Perosa, Alvise; Tundo, Pietro; Brunelli, Davide

    2006-07-21

    In the presence of onium salts, at 140-170 degrees C, methyl alkyl carbonates [1a-c, ROCO2Me, R = MeO(CH2)2[O(CH2)2]n; n = 2-0, respectively] react with primary aromatic amines (XC6H4NH2, X= p-OMe, p-Me, H, p-Cl, p-CO2Me, o-Et, and 2,3-Me2C6H3NH2) to yield the corresponding N,N-dimethyl derivatives (ArNMe2) with high selectivity (up to 96%) and good isolated yields (78-95%). Phosphonium salts (e.g., Ph3PEtI and n-Bu4PBr) are particularly efficient catalysts. Overall, a solvent-free reaction is coupled with safe methylating agents (1a-c) made from nontoxic dimethyl carbonate.

  2. Synthesis of Aliphatic Symmetric Diphosphonium Salts and Bactericidal Activity of Selected Products

    Directory of Open Access Journals (Sweden)

    Bin Yuan

    2017-06-01

    Full Text Available Eight new aliphatic symmetrical diphosphonium salts were synthesized by reacting ω,ω´-dibromoalkanes with triphenylphosphine or tributylphosphine using N,N-dimethyl acetamide as a solvent at 140~150°C for 16~20 h under a nitrogen atmosphere.

  3. Foraging site choice and diet selection of Meadow Pipits Anthus pratensis breeding on grazed salt marshes

    NARCIS (Netherlands)

    van Klink, Roel; Mandema, Freek S.; Bakker, Jan P.; Tinbergen, Joost M.

    2014-01-01

    Capsule Breeding Meadow Pipits foraged for caterpillars and large spiders in vegetation that was less heterogeneous than vegetation at random locations.Aims To gain a better understanding of the foraging ecology of breeding Meadow Pipits on grazed coastal salt marshes, we tested three hypotheses:

  4. Precipitation regime for selected amino acid salts for CO2 capture from flue gases

    NARCIS (Netherlands)

    Majchrowicz, Magdalena E.; Brilman, Derk Willem Frederik; Groeneveld, M.J.

    2009-01-01

    The tendency of alkaline (sodium, potassium and lithium) salts of taurine, β-alanine, sarcosine and L-proline to form precipitates under varying operational conditions of CO2 absorption has been investigated. CO2 absorption experiments have been performed at 293.15 and 313.15 K, at partial pressures

  5. Premixed Digestion Salts for Kjeldahl Determination of Total Nitrogen in Selected Forest Soils

    Science.gov (United States)

    B. G. Blackmon

    1971-01-01

    Estimates of total soil nitrogen by a standard Kjeldahl procedure and a modified procedure employing packets of premixed digestion salts were closely correlated. (r2 = 0.983). The modified procedure appears to be as reliable all the standard method for determining total nitrogen in southern alluvial forest soils.

  6. Correction: A binary catalyst system of a cationic Ru-CNC pincer complex with an alkali metal salt for selective hydroboration of carbon dioxide.

    Science.gov (United States)

    Ng, Chee Koon; Wu, Jie; Hor, T S Andy; Luo, He-Kuan

    2016-12-22

    Correction for 'A binary catalyst system of a cationic Ru-CNC pincer complex with an alkali metal salt for selective hydroboration of carbon dioxide' by Chee Koon Ng et al., Chem. Commun., 2016, 52, 11842-11845.

  7. Crystallographic investigations of select cathinones: emerging illicit street drugs known as `bath salts'.

    Science.gov (United States)

    Wood, Matthew R; Lalancette, Roger A; Bernal, Ivan

    2015-01-01

    The name `bath salts', for an emerging class of synthetic cathinones, is derived from an attempt to evade prosecution and law enforcement. These are truly illicit drugs that have psychoactive CNS (central nervous system) stimulant effects and they have seen a rise in abuse as recreational drugs in the last few years since first having been seen in Japan in 2006. The ease of synthesis and modification of specific functional groups of the parent cathinone make these drugs particularly difficult to regulate. MDPV (3,4-methylenedioxypyrovalerone) is commonly encountered as its hydrochloride salt (C16H21NO3·HCl), in either the hydrated or the anhydrous forms. This `bath salt' has various names in the US, e.g. `Super Coke', `Cloud Nine', and `Ivory Wave', to name just a few. We report here the structures of two forms of the HCl salt, one as a mixed bromide/chloride salt, C16H22NO3(+)·0.343Br(-)·0.657Cl(-) [systematic name: 1-(benzo[d][1,3]dioxol-5-yl)-2-(pyrrolidin-1-ium-1-yl)pentan-1-one bromide/chloride (0.343/0.657)], and the other with the H7O3(+) cation, as well as the HCl counter-ion [systematic name: hydroxonium 1-(benzo[d][1,3]dioxol-5-yl)-2-(pyrrolidin-1-ium-1-yl)pentan-1-one dichloride, H7O3(+)·C16H22NO3(+)·2Cl(-)]. This is one of a very few structures (11 to be exact) in which we have a new example of a precisely determined hydroxonium cation. During the course of researching the clandestine manufacture of MDPV, we were surprised by the fact that a common precursor of this illicit stimulant is known to be the fragrant species piperonal, which is present in the fragrances of orchids, most particularly in the case of the vanilla orchid. We found that MDPV can be made by a Grignard reaction of this heliotropin. This may also explain the unexpected appearance of the bromide counter-ion in some of the salts we encountered (C16H21NO3·HBr), one of which is presented here [systematic name: 1-(benzo[d][1,3]dioxol-5-yl)-2-(pyrrolidin-1-ium-1-yl)pentan-1-one

  8. Identification and Selection for Salt Tolerance in Alfalfa (Medicago sativa L. Ecotypes via Physiological Traits

    Directory of Open Access Journals (Sweden)

    Hassan MONIRIFAR

    2009-12-01

    Full Text Available Salt stress is a serious environmental problem throughout the world which may be partially relieved by breeding cultivars that can tolerate salt stress. Plant breeding may provide a relatively cost effective short-term solution to the salinity problem by producing cultivars able to remain productive at low to moderate levels of salinity. Five alfalfa cultivars, �Seyah-Roud�, �Ahar-Hourand�, �Oskou�, �Malekan� and �Sefida-Khan� were assessed for salt tolerance at mature plant stage. A greenhouse screening system was used to evaluate individual alfalfa plants grown in perlit medium, and irrigated with water containing different amounts of NaCl. Three salt levels were achieved by adding 0, 100 and 200 mM NaCl to Hoagland nutrient solution, respectively. Forage yield, sodium and potassium contents and K/Na ratio was determined. Also, leaf samples were analyzed for proline and chlorophyll contents. The ecotypes Seyha-Roud and �Sefida-Khan� had comparatively less sodium contents than �Oskou�, �Ahar-Hourand� and �Malekan� ecotypes, also potassium content increased under saline condition. Forage yield of different alfalfa ecotypes was significantly influenced by the salinity. The ecotypes �Malekan�, Ahar- Hourand and �Oskou� were successful in maintaining forage yield under salinity stress. Sodium contents increased due to salinity in all alfalfa ecotypes however ecotypes �Ahar-Hourand� and �Malekan� maintained the highest leaf Na concentration. They showed higher content of K than other ecotypes but had lower K/Na ratio. It was concluded that, two ecotypes �Malekan� and �Ahar-Hourand� were better.

  9. Selective activation of hTRPV1 by N-geranyl cyclopropylcarboxamide, an amiloride-insensitive salt taste enhancer.

    Directory of Open Access Journals (Sweden)

    Min Jung Kim

    Full Text Available TRPV1t, a variant of the transient receptor potential vanilloid-1 (TRPV1 has been proposed as a constitutively active, non-selective cation channel as a putative amiloride-insensitive salt taste receptor and shares many properties with TRPV1. Based on our previous chorda tympani taste nerve recordings in rodents and human sensory evaluations, we proposed that N-geranylcyclopropylcarboxamide (NGCC, a novel synthetic compound, acts as a salt taste enhancer by modulating the amiloride/benzamil-insensitive Na(+ entry pathways. As an extension of this work, we investigated NGCC-induced human TRPV1 (hTRPV1 activation using a Ca(2+-flux signaling assay in cultured cells. NGCC enhanced Ca(2+ influx in hTRPV1-expressing cells in a dose-dependent manner (EC50 = 115 µM. NGCC-induced Ca(2+ influx was significantly attenuated by ruthenium red (RR; 30 µM, a non-specific blocker of TRP channels and capsazepine (CZP; 5 µM, a specific antagonist of TRPV1, implying that NGCC directly activates hTRPV1. TRPA1 is often co-expressed with TRPV1 in sensory neurons. Therefore, we also investigated the effects of NGCC on hTRPA1-expressing cells. Similar to hTRPV1, NGCC enhanced Ca(2+ influx in hTRPA1-expressing cells (EC50 = 83.65 µM. The NGCC-induced Ca(2+ influx in hTRPA1-expressing cells was blocked by RR (30 µM and HC-030031 (100 µM, a specific antagonist of TRPA1. These results suggested that NGCC selectively activates TRPV1 and TRPA1 in cultured cells. These data may provide additional support for our previous hypothesis that NGCC interacts with TRPV1 variant cation channel, a putative amiloride/benzamil-insensitive salt taste pathway in the anterior taste receptive field.

  10. Excitation Frequencies of the Effects of Selective Drift of Solvated Cations in Moving Salts Solution

    Directory of Open Access Journals (Sweden)

    Shamanin Igor

    2017-01-01

    Full Text Available Interaction of external electric field with free and bound charges in the salt solution volume in polar dielectric fluid was considered and the equation describing ion oscillations relative to solvent molecules was obtained. Fundamental frequencies of the solvation shell relative to the ion in different approximations describing the system: ion - solvation shell were evaluated. The results of comparison with the experiment pointed out that the model, in which the solvated ion is considered as a spherical rotator formed by the solvent molecules layer bordering with the external solvation shell, is the most appropriate. It provides an opportunity of development of new technologies for extraction of rare earth elements.

  11. The organometallic fluorine chemistry of palladium and rhodium: studies toward aromatic fluorination.

    Science.gov (United States)

    Grushin, Vladimir V

    2010-01-19

    Although springing from two established fields, organometallic chemistry and fluorine chemistry, organometallic fluorine chemistry is still in its early stages. However, developments in this area are expected to provide new tools for the synthesis of selectively fluorinated organic compounds that have been in high demand. Selectively fluorinated organic molecules currently account for up to 40% of all agrochemicals and 20% of all pharmaceuticals on the market. Our research efforts have been focused on the development of new organometallic and catalytic methods for the selective introduction of fluorine and the CF(3) group into the aromatic ring. Monofluorinated and trifluoromethylated aromatic compounds are still made by the old technologies that employ stoichiometric quantities of hazardous and costly materials. In this Account, we describe our studies toward the development of safe, catalytic alternatives to these methods. We have synthesized, characterized, and studied the reactivity of the first aryl palladium(II) fluoride complexes. We have demonstrated for the first time that a Pd-F bond can be formed in a soluble and isolable molecular complex: this bond is more stable than previously thought. Toward the goal of fluoroarene formation via Ar-F reductive elimination, we have studied a number of sigma-aryl Pd(II) fluorides stabilized by various P, N, and S ligands. It has been established that numerous conventional tertiary phosphine ligands, most popular in Pd catalysis, are unlikely to be useful for the desired C-F bond formation at the metal center because of the competing, kinetically preferred P-F bond-forming reaction. A metallophosphorane mechanism has been demonstrated for the P-F bond-forming processes at Rh(I) and Pd(II), which rules out the possibility of controlling these reactions by varying the amount of phosphine in the system, a most common and often highly efficient technique in homogeneous catalysis. The novel F/Ph rearrangement of the fluoro

  12. The Curious Case of Fluorination of Conjugated Polymers for Solar Cells.

    Science.gov (United States)

    Zhang, Qianqian; Kelly, Mary Allison; Bauer, Nicole; You, Wei

    2017-09-19

    Organic solar cells (OSCs) have been a rising star in the field of renewable energy since the introduction of the bulk heterojunction (BHJ) in 1992. Recent advances have pushed the efficiencies of OSCs to over 13%, an impressive accomplishment via collaborative efforts in rational materials design and synthesis, careful device engineering, and fundamental understanding of device physics. Throughout these endeavors, several design principles for the conjugated donor polymers used in such solar cells have emerged, including optimizing the conjugated backbone with judicious selection of building blocks, side-chain engineering, and substituents. Among all of the substituents, fluorine is probably the most popular one; improved device characteristics with fluorination have frequently been reported for a wide range of conjugated polymers, in particular, donor-acceptor (D-A)-type polymers. Herein we examine the effect of fluorination on the device performance of solar cells as a function of the position of fluorination (on the acceptor unit or on the donor unit), aiming to outline a clear understanding of the benefits of this curious substituent. As fluorination of the acceptor unit is the most adopted strategy for D-A polymers, we first discuss the effect of fluorination of the acceptor units, highlighting the five most widely utilized acceptor units. While improved device efficiency has been widely observed with fluorinated acceptor units, the underlying reasons vary from case to case and highly depend on the chemical structure of the polymer. Second, the effect of fluorination of the donor unit is addressed. Here we focus on four donor units that have been most studied with fluorination. While device-performance-enhancing effects by fluorination of the donor units have also been observed, it is less clear that fluorine will always benefit the efficiency of the OSC, as there are several cases where the efficiency drops, in particular with "over-fluorination", i.e., when

  13. Diastereodivergent Synthesis of Fluorinated Cyclic β(3)-Amino Acid Derivatives.

    Science.gov (United States)

    Aparici, Isabel; Guerola, Marta; Dialer, Clemens; Simón-Fuentes, Antonio; Sánchez-Roselló, María; del Pozo, Carlos; Fustero, Santos

    2015-11-06

    The ability of 2-p-tolylbenzyl carbanions to behave as a source of chiral benzylic nucleophiles has been shown in its reaction with fluorinated imines. The process takes place with high levels of stereocontrol, rendering the corresponding amines as single diastereoisomers. Subsequent cross-metathesis followed by intramolecular aza-Michael reaction makes the synthesis of fluorinated homoproline derivatives bearing three stereogenic centers possible. Furthermore, the selectivity of the cyclization process can easily be tuned up in a diastereodivergent manner simply by changing the reaction conditions.

  14. RECOVERY OF Pu FROM CERIUM TRIFLUORIDE BY FLUORINATION

    Science.gov (United States)

    Brown, H.S.; Bohlmann, E.G.

    1959-02-10

    An improved process is prcsented for selectively recovering plutonium from a solution containing fission products comprising precipitating cerium trifluoride in the solution for effccting carrier precipitation of plutonium. The resulting carrier precipitate is dried and subjected to fluorination at about 600 C. The plutonium forms a volatile fiuoridc and is so separated from the nonvolatile cerium fluoride.

  15. Restricting the Solubility of Polysulfides in Li-S Batteries Via Electrolyte Salt Selection

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Junzheng [Joint Center for Energy Storage Research (JCESR), Pacific Northwest National Laboratory, Richland WA 99352 USA; Han, Kee Sung [Joint Center for Energy Storage Research (JCESR), Pacific Northwest National Laboratory, Richland WA 99352 USA; Henderson, Wesley A. [Joint Center for Energy Storage Research (JCESR), Pacific Northwest National Laboratory, Richland WA 99352 USA; Lau, Kah Chun [Joint Center for Energy Storage Research (JCESR), Argonne National Laboratory, Argonne IL 60439 USA; Vijayakumar, Murugesan [Joint Center for Energy Storage Research (JCESR), Pacific Northwest National Laboratory, Richland WA 99352 USA; Dzwiniel, Trevor [Joint Center for Energy Storage Research (JCESR), Argonne National Laboratory, Argonne IL 60439 USA; Pan, Huilin [Joint Center for Energy Storage Research (JCESR), Pacific Northwest National Laboratory, Richland WA 99352 USA; Curtiss, Larry A. [Joint Center for Energy Storage Research (JCESR), Argonne National Laboratory, Argonne IL 60439 USA; Xiao, Jie [Joint Center for Energy Storage Research (JCESR), Pacific Northwest National Laboratory, Richland WA 99352 USA; Mueller, Karl T. [Joint Center for Energy Storage Research (JCESR), Pacific Northwest National Laboratory, Richland WA 99352 USA; Shao, Yuyan [Joint Center for Energy Storage Research (JCESR), Pacific Northwest National Laboratory, Richland WA 99352 USA; Liu, Jun [Joint Center for Energy Storage Research (JCESR), Pacific Northwest National Laboratory, Richland WA 99352 USA

    2016-03-29

    Polysulfide solubility in the electrolyte has a critical role to the Li-S battery but the mechanism study on the solubility needs to be carefully carried out. In this paper we found that lithium 2-trifluoromethyl-4,5-dicyanoimidazole (LiTDI) reveals a suppression of the polysulfide solubility in electrolytes (relative to the most widely used electrolyte formulation) and the Li-S cells achieved homogeneous stable capacity retention upon extensive cycling and Li metal deposition on the anode. Combined experimental, simulation and calculation methods suggest the dominate disproportionation product of Li2S8 is Li2S4 in the LiTDI electrolyte due to a different interaction between lithium ion and TDI anion. The Li2S4 would continuesly form a Li4S8 dimer and be fully locallized to precipitate out. The use of the electrolyte with the LiTDI salt (with polysulfide and LiNO3 additives) enabled a cell with a high sulfur (3 mg-S cm-2) loading to deliver a 1.67 mAh cm-2 areal capacity after 300 stable cycles at a high current (2.4 mA cm-2) density.

  16. PRODUCTION OF FLUORINE-CONTAINING HYDROCARBON

    Science.gov (United States)

    Sarsfield, N.F.

    1949-08-01

    This patent relates to improvements in the production of fluorine- containing hydrocarbon derivatives. The process for increasing the degree of fluorination of a fluorochlorohydrocarbon comprises subjecting a highly fluorinated fluorochlorohydrocarbon to the action of a dehydrochlorinating agent, and treating the resulting unsaturated body with fluorine, cobalt trifluoride, or silver difluoride. A number of reagents are known as dehydrochlorinaling agents, including, for example, the caustic alkalies, either in an anhydrous condition or dissolved in water or a lower aliphatic alcohol.

  17. Polyfluorides and Neat Fluorine as Host Material in Matrix-Isolation Experiments.

    Science.gov (United States)

    Brosi, Felix; Vent-Schmidt, Thomas; Kieninger, Stefanie; Schlöder, Tobias; Beckers, Helmut; Riedel, Sebastian

    2015-11-09

    The use of neat fluorine in matrix isolation is reported, as well as the formation of polyfluoride monoanions under cryogenic conditions. Purification procedures and spectroscopic data of fluorine are described, and matrix shifts of selected molecules and impurities in solid fluorine are compared to those of common matrix gases (Ar, Kr, N2 , Ne). The reaction of neat fluorine and IR-laser ablated metal atoms to yield fluorides of chromium (CrF5 ), palladium (PdF2 ), gold (AuF5 ), and praseodymium (PrF4 ) has been investigated. The fluorides have been characterized in solid fluorine by IR spectroscopy at 5 K. Also the fluorination of Kr and the photo-dismutation of XeO4 have been studied by using IR spectroscopy in neat fluorine. Formation of the [F5 ](-) ion was obtained by IR-laser ablation of platinum in the presence of fluorine and proven in a Ne matrix at 5 K by two characteristic vibrational bands of [F5 ](-) at $\\tilde \

  18. [Microstructure and spectral property of Er3+ doped transparent oxyfluoride glass ceramics with high fluorine contents].

    Science.gov (United States)

    Lin, Le-Jing; Ren, Guo-Zhong; Chen, Min-Peng; Liu, Yang

    2009-12-01

    The microstructure and spectral properties of Er3+ doped transparent oxyfluoride glass ceramics with high fluorine content were reported. Two samples with the same initial contents (50SiO2-45PbF2-5PbO-1ErF3) were prepared under the different preparation parameters. The final fluorine contents were detected by a fluoride ion selective electrode. The results shows that the final fluorine contents increase by covering crucibles with corundum lid during melt. The samples were characterized by X-ray diffraction, transmission electron microscopy (TEM), absorption spectra and upconversion luminescence spectra. The results show that PbF2 crystals were precipitated in the sample with high fluorine content before heat treatment. And the PbF2 crystals precipitated inside the glass matrix are spherical with diameters of approximately 10-15 nm in size from the high resolution TEM micrograph. The absorption spectra, J-O parameters and the upconversion spectra show that the Er3+ ions were located in crystalline and vitreous mixed states. It is different from the sample with low fluorine content which is completely amorphous. After heat treatment, Er3+ ions that remain in the glassy phase entered into fluoride nanocrystals in the sample with high fluorine content. The fluorine environment decreases non-radiative transfer which eases the upconversion processes. Hence, the upconversion luminescence intensity of Er3+ ions in the high fluorine content sample after heat treatment is much stronger than that in the precursor sample.

  19. Synthesis and properties of high tilted antiferroelectric esters with partially fluorinated alkoxyalkoxy terminal chains

    Science.gov (United States)

    Żurowska, M.; Dąbrowski, R.; Dziaduszek, J.; Czupryński, K.; Skrzypek, K.; Filipowicz, M.; Bennis, N.; Otón, J. M.

    2008-09-01

    Novel chiral esters with partially fluorinated alkoxyalkoxy terminal chains are described. Their phase transition temperatures, enthalpies, and electrooptical properties are reported. A helical pitch in pure compounds and their mixtures based on selective reflection of light is also characterized.

  20. Selective growth of Staphylococcus aureus from flushed dairy manure wastewater using acriflavine-supplemented mannitol salt agar.

    Science.gov (United States)

    Davis, J A; Farrah, S R; Wilkie, A C

    2006-06-01

    To investigate the use of mannitol salt agar (MSA) supplemented with acriflavine for selective growth and quantification of Staphylococcus aureus from flushed dairy manure wastewater (FDMW). Minimal inhibitory concentrations of acriflavine in MSA were determined by comparing the growth of S. aureus subsp. aureus (ATCC 33591) and Staphylococcus epidermidis (ATCC 155) in pure culture. Acriflavine concentrations of 1.3, 1.4 and 1.5 mg l(-1) reduced CFU of S. epidermidis by 43%, 55% and 87%, respectively, while CFU of S. aureus subsp. aureus were only reduced by 15%, 20% and 26% at the respective concentrations of acriflavine. MSA supplemented with 1.5 mg l(-1) acriflavine was tested for selective growth of indigenous S. aureus from three grab samples of FDMW. Acriflavine concentrations of 1.5 mg l(-1) reduced background flora without significantly reducing (P < 0.05) indigenous S. aureus counts. Acriflavine-supplemented MSA provides an effective media for selective growth and quantification of indigenous S. aureus from FDMW in the presence of high levels of background microflora. S. aureus is implicated for mastitis infections in dairy cows. Therefore, a reliable means for monitoring and detecting the organism in FDMW provides a tool for measuring the effectiveness of treatment for reducing S. aureus levels and implementing flushwater recycling without affecting herd health.

  1. E- or Z-Selective synthesis of 4-fluorovinyl-1,2,3-triazoles with fluorinated second-generation Julia-Kocienski reagents.

    Science.gov (United States)

    Kumar, Rakesh; Singh, Govindra; Todaro, Louis J; Yang, Lijia; Zajc, Barbara

    2015-02-07

    A highly modular approach to N-substituted 4-(1-fluorovinyl)triazoles is described. In situ desilylation and Cu-catalyzed ligation reaction of TMS-protected α-fluoropropargyl benzothiazole sulfone with aryl, alkyl, and metallocenyl azides furnished second-generation Julia-Kocienski reagents in good to excellent yields. Condensation reactions of these reagents with aldehydes can be tuned to yield E or Z-alkenes selectively. Under mild conditions with DBU as the base, reactions of aldehydes furnished E-alkenes as the major isomer. On the other hand, in condensation reactions with LHMDS as the base and in appropriate solvents, both aldehydes and ketones reacted to yield fluoroalkenes with Z-selectivity. Stereochemical assignment of E/Z olefins obtained in the reaction of a ketone with two Julia reagents was performed via X-ray crystallographic analysis and comparisons of NMR data. The method allows efficient and ready diversification of the N1-substituent and substituents at the double bond.

  2. [Salt tolerance evaluation of cotton (Gossypium hirsutum) at its germinating and seedling stages and selection of related indices].

    Science.gov (United States)

    Zhang, Guo-wei; Lu, Hai-ling; Zhang, Lei; Chen, Bing-lin; Zhou, Zhi-guo

    2011-08-01

    A sand culture experiment was conducted to study the salt tolerance of 13 cotton cultivars at their germinating and seedling stages under the stress of different concentration NaCl, and a cluster analysis was made on the salt tolerance, according to the subjection values of salt toxicity coefficients of multi-indices and the sum subjection value. It was observed that the appropriate concentration of NaCl for the evaluation of salt tolerance was 150 mmol x L(-1). The salt tolerance differed with cultivar and growth stage. Among the 13 cultivars, the CCRI-44 and CCRI-177 were steadily salt-tolerant at both germinating and seedling stages, the CCRI-103, Dexiamian 1, and NuCOTN 33B were steadily and moderately salt-tolerant, while the CCRI-102, Sumian 12, and Simian 3 were steadily salt-sensitive. Germination rate, germination potential, germination index, vigor index, and fresh mass could be served as the indicators to evaluate the salt tolerance of the cultivars at germinating stage, while plant height, leaf expansion rate, shoot dry mass, root dry mass, root vigor, and net photosynthetic rate could be applied to assess the salt tolerance at seedling stage.

  3. Properties of Fluorinated Graphene Films

    Science.gov (United States)

    2010-04-01

    Properties of Fluorinated Graphene Films Jeremy T. Robinson,* James S. Burgess, Chad E. Junkermeier, Stefan C. Badescu, Thomas L. Reinecke, F. Keith ...Chem. Soc., Dalton Trans. 1974, 1268–1273. (4) Taylor, R.; Holloway, J. H.; Hope, E. G.; Avent, A. G.; Langley, G. J.; Dennis, T. J.; Hare , J. P

  4. New Fluorinated and Sulfonated Block Copolymers Final Report

    Science.gov (United States)

    2009-04-23

    fossil fuels, are a pressing need in the world we live in today. One such promising alternative is a fuel cell. Fuel Cells are typically classified...1H NMR . Some samples were neutralized to the cesium salt form , and the balance left in the acid form. The cesium form facilitates contrast in the x...characteristics: Mw =31,200 ,PDI=1.05, 27mol% PS. The fluorinated samples cast into membranes were sulfonated to 23,28 and 50 mol%, as determined by 1H NMR

  5. Synthesis of Branch Fluorinated Cationic Surfactant and Surface Properties

    Directory of Open Access Journals (Sweden)

    Hongke Wu

    2014-01-01

    Full Text Available A novel fluorinated quaternary ammonium salt cationic surfactant N,N,N-trimethyl-2-[[4-[[3,4,4,4-tetrafluoro-2-[1,2,2,2-tetrafluoro-1-(trifluoromethylethyl]-1,3-bis(tri-fluoromethyl-1-buten-1-yl]oxy]-benzoyl]amino]-iodide (FQAS was synthesized successfully, and its structure was characterized by FTIR, 1H-NMR, 19F-NMR, and MS. The surface activities of FQAS and the effect of temperature, electrolyte, and combination with hydrocarbon surfactant were investigated. The results showed that FQAS exhibited excellent surface activity and combination with hydrocarbon surfactant.

  6. Adsorption and diffusion of fluorine on Cr-doped Ni(111) surface: Fluorine-induced initial corrosion of non-passivated Ni-based alloy

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Cui-Lan, E-mail: rencuilan@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Key Laboratory of Interfacial Physics and Technology, Chinese Academy of Sciences, Shanghai 201800 (China); Han, Han [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Gong, Wen-Bin [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Shanghai 215123 (China); Wang, Cheng-Bin; Zhang, Wei [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Key Laboratory of Interfacial Physics and Technology, Chinese Academy of Sciences, Shanghai 201800 (China); Cheng, Cheng [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Huai, Ping, E-mail: huaiping@sinap.ac.cn [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Zhu, Zhi-Yuan [Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800 (China); Key Laboratory of Interfacial Physics and Technology, Chinese Academy of Sciences, Shanghai 201800 (China)

    2016-09-15

    Adsorption and diffusion behaviors of fluorine on Cr-doped Ni(111) surface are investigated by using first-principles simulation. It shows that the Cr in the Cr-doped Ni(111) surface serve a trap site for fluorine with adsorption energy 3.52 eV, which is 1.04 eV higher than that on Ni(111) surface. Moreover, the Cr atom is pulled out the surface for 0.41 Å after the fluorine adsorption, much higher than that on Ni(111) surface. Further diffusion behaviors analysis confirms the conclusion because the fluorine diffusion from neighbored sites onto the Cr top site is an energy barrierless process. Detailed electronic structure analysis shows that a deeper hybrid state of F 2 p-Cr 3 d indicates a strong F−Cr interaction. The Ni−Cr bond is elongated and weakened due to the new formed F−Cr bonding. Our results help to understanding the basic fluorine-induced initial corrosion mechanism for Ni-based alloy in molten salt environment.

  7. Design, synthesis, and characterization of fluorine-free PAGs for 193-nm lithography

    Science.gov (United States)

    Liu, Sen; Glodde, Martin; Varanasi, Pushkara R.

    2010-04-01

    Photoacid generators (PAGs) are a key component in chemically amplified resists used in photolithography. Perfluorooctanesulfonates (PFOS) and other perfluoroalkylsulfonates (PFAS) have been well adopted as PAGs in 193 nm photoresist. Recently, concerns have been raised about their environmental impact due to their chemical persistency, bioaccumulation and toxicity. It is a general interest to find environmentally benign PAGs that are free of fluorine atoms. Here we describe the design, synthesis and characterization of a series of novel fluorine-free onium salts as PAGs for 193 nm photoresists. These PAGs demonstrated desirable physical and lithography properties when compared with PFAS-based PAGs for both dry and immersion exposures.

  8. Robust outer-selective thin-film composite polyethersulfone hollow fiber membranes with low reverse salt flux for renewable salinity-gradient energy generation

    KAUST Repository

    Cheng, Zhen Lei

    2016-01-08

    This study reports outer-selective thin-film composite (TFC) hollow fiber membranes with extremely low reverse salt fluxes and robustness for harvesting salinity-gradient energy from pressure retarded osmosis (PRO) processes. Almost defect-free polyamide layers with impressive low salt permeabilities were synthesized on top of robust polyethersulfone porous supports. The newly developed TFC-II membrane shows a maximum power density of 7.81 W m−2 using 1 M NaCl and DI water as feeds at 20 bar. Reproducible data obtained in the 2nd and 3rd runs confirm its stability under high hydraulic pressure differences. Comparing to other PRO membranes reported in the literature, the newly developed membrane exhibits not only the smallest slope between water flux decline and ΔPΔP increase but also the lowest ratio of reverse salt flux to water flux. Thus, the effective osmotic driving force could be well maintained even under high pressure operations. For the first time, the effect of feed pressure buildup induced by feed flowrate was evaluated towards PRO performance. A slight increment in feed pressure buildup was found to be beneficial to water flux and power density up to 10.06 W m−2 without comprising the reverse salt flux. We believe this study may open up new perspectives on outer-selective PRO hollow fiber membranes and provide useful insights to understand and design next-generation outer-selective TFC hollow fiber membranes for osmotic power generation.

  9. Application of 19F NMR Spectroscopy for Content Determination of Fluorinated Pharmaceuticals

    Directory of Open Access Journals (Sweden)

    Alex O. Okaru

    2017-01-01

    Full Text Available A simple, rapid, and selective quantitative nuclear magnetic resonance spectroscopic method was evaluated for the determination of the content of fluorinated pharmaceuticals. 19F NMR spectra were either obtained in dimethylsulfoxide-d6 or aqueous buffer, using trifluoroacetic acid as internal standard. Quantification of 13 fluorine-containing pharmaceuticals spanning various pharmacological classes was accomplished using the proposed method. The method was found to be fit for purpose (interday precision 1.2% relative standard deviation and may thus be applied for routine analysis and quality control of fluorine-containing pharmaceuticals due to its simplicity, nondestructive sample measurement, reliability, and high specificity. Therefore, 19F NMR may serve as a suitable analytical tool for the identification and selective determination of fluorinated pharmaceuticals used as reference materials and bulk samples.

  10. Effect of mobile phase composition on the retention of selected alkaloids in reversed-phase liquid chromatography with chaotropic salts.

    Science.gov (United States)

    Flieger, J

    2007-12-21

    Sodium hexafluorophosphate, perchlorate and trifluoroacetate were applied as ion-ion interaction reagents in reversed-phase liquid chromatography. The separation of chosen alkaloids was performed by changing the kind of the organic modifier (methanol, acetonitrile, tetrahydrofuran), concentration of the ion-ion-interaction reagents and the concentration of phosphate buffer at constant pH (2.7) in the mobile phase. Obtained results were analyzed in connection to a dynamic ion-exchange model of retention and ion-ion interaction effects. The perturbation method was applied to test proposed retention theories. The formation of ion-complexes controlling the retention in chaotropic systems was confirmed. On the basis of the relationships of capacity factors (k) versus salt concentrations derived experimentally, absolute increases in capacity factors, the desolvation parameters and the limiting retention factors were calculated and compared for all the investigated compounds in eluent systems studied. The selectivity of the proposed mobile phases was compared on the basis of the separation of alkaloid mixture.

  11. 77 FR 32146 - Safety Evaluation Report, International Isotopes Fluorine Products, Inc., Fluorine Extraction...

    Science.gov (United States)

    2012-05-31

    ... summary, radiation protection, nuclear criticality safety, chemical process safety, fire safety, emergency... COMMISSION Safety Evaluation Report, International Isotopes Fluorine Products, Inc., Fluorine Extraction Process and Depleted Uranium Deconversion Plan, Lea County, NM AGENCY: Nuclear Regulatory Commission...

  12. Research in Inorganic Fluorine Chemistry.

    Science.gov (United States)

    1987-03-01

    Corporation , Canoga Park, California 91304 (U.S.A.) SUMMARY A new synthesis of FOC1O 3 was discovered involving the fluorination of C10 4 with C1F 6 + An... Corporation . Canoga Park. Califoriai 91304 * Gas-Phase Shtrutre of Azidotrifluoromdmaae. Am Electron Diffractio. Microwave Spectroscopy, sold NormaI...hexafluorobenzene as start- GG-4 N 7 ~ 4,476,3378 Nll materials. All reacted gradually at, or near, m76nt 3 temperaturae . All solutions and products were

  13. Special Feature Organo-Fluorine Chemical Science

    Directory of Open Access Journals (Sweden)

    Helmut Martin Hügel

    2012-06-01

    Full Text Available Fluorine is the 13th most abundant element and, with other fluorine containing functional groups, is a most effective element in biological substances, pharmaceuticals, agrochemicals, liquid crystals, dyes, polymers and a wide range of consumer products. This reflects its resistance to metabolic change due to the strength of the C-F bond providing biological stability and the application of its nonstick-interfacial physical characteristics. Its introduction often remains a synthetic challenge. The widespread use of organofluorines has increased the demand for the development of practical and simple reagents and experimental strategies for the incorporation of fluorine into all types of molecular structures and this was the reasoning behind this special feature on Organo-Fluorine Chemical Science.The contributed articles belong to two broad groups: (i preparation of fluorine materials, polymers; (ii the synthesis/applications of organo-fluorine molecules. [...

  14. Fluorine content in epiphtic lichens and mosses

    Energy Technology Data Exchange (ETDEWEB)

    Olech, M.; Kajfosz, J.; Szymczyk, S.; Wodniecki, P.

    1981-01-01

    The fluorine content in epiphytic lichens (Physcia adscendens, Physconia grisea, Parmelia sulcata and Evernia prunastri) and the moss Orthotrichum obtusifolium growing near an aluminum plant is presented. Analyses of lichen samples show the correlation between the distribution of the emitted fluorine and the distance from the source of emission; the most visible effects are in the direction of the prevailing winds. The more resistant lichen species accumulate greater amounts of fluorine than the less resistant ones.

  15. Feasibility study of semi-selective protein precipitation with salt-tolerant copolymers for industrial purification of therapeutic antibodies.

    Science.gov (United States)

    Capito, Florian; Bauer, Johann; Rapp, Almut; Schröter, Christian; Kolmar, Harald; Stanislawski, Bernd

    2013-11-01

    We present a feasibility study for an antibody capturing process from clarified cell culture fluid using semi-selective protein precipitation with salt-tolerant copolymers. Protein precipitation is mediated by hydrophobic and electrostatic interactions with the copolymer that can be customized for the respective target. Precipitation yield with different copolymers at ionic strength of 2-22.5 mS cm⁻¹ and pH 5.0-pH 5.7 was evaluated using pure monoclonal antibody solutions. Optimized parameters were used to elucidate yield and purity of various antibodies precipitated at physiological conditions from cell culture fluid of CHO, NS0, and SP2/0 cell culture fluid. Precipitated protein was easily redissolved in small volume, enabling concentrating monoclonal antibodies (mAb) more than 40-fold and up to 100-fold, while residual polymer was removed to >98% using cationic polymer attached to silica flakes. mAb recovery of >90% and host cell protein clearance of >80% were achieved, not requiring any pre-dilution of cell culture fluid. Precipitation showed no impact on mAb binding affinity when compared to non-precipitated mAb. The obtained yield and purity were lower compared to a protein A based purification and loss of mAb was factor 1.5-3.0 higher. Yet, for high titer mAb purification processes being implemented in the future, precipitation is an attractive option due to its ease of scalability and cost-effectiveness. © 2013 Wiley Periodicals, Inc.

  16. Synthetic Aspects and Electro-Optical Properties of Fluorinated Arylenevinylenes for Luminescence and Photovoltaics

    Directory of Open Access Journals (Sweden)

    Antonio Cardone

    2013-03-01

    Full Text Available In this review, the main synthetic aspects and properties of fluorinated arylenevinylene compounds, both oligomers and polymers, are summarized and analyzed. Starting from vinyl organotin derivatives and aryl halides, the Stille cross-coupling reaction has been successfully applied as a versatile synthetic protocol to prepare a wide series of π-conjugated compounds, selectively fluorinated on the aromatic and/or vinylene units. The impact of fluoro-functionalization on properties, the solid state organization and intermolecular interactions of the synthesized compounds are discussed, also in comparison with the non-fluorinated counterparts. Luminescent and photovoltaic applications are also discussed, highlighting the role of fluorine on the performance of devices.

  17. A binary catalyst system of a cationic Ru-CNC pincer complex with an alkali metal salt for selective hydroboration of carbon dioxide.

    Science.gov (United States)

    Ng, Chee Koon; Wu, Jie; Hor, T S Andy; Luo, He-Kuan

    2016-09-27

    Binary catalyst systems comprising a cationic Ru-CNC pincer complex and an alkali metal salt were developed for selective hydroboration of CO2 utilizing pinacolborane at r.t. and 1 atm CO2, with the combination of [Ru(CNCBn)(CO)2(H)][PF6] and KOCO2(t)Bu producing formoxyborane in 76% yield. A bicyclic catalytic mechanism was proposed and discussed.

  18. Asymmetric Electrophilic Fluorination of β-Keto Phosphonates in Ionic Liquid Media Catalyzed by Chiral Palladium Complexes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Min; Kang, Young Ku; Mang, Joo Yang; Kim, Dae Young [Soonchunhyang University, Asan (Korea, Republic of); Lee, Kil Sung [Cheil Industries Inc., Euiwang, (Korea, Republic of)

    2006-03-15

    We have accomplished the highly efficient catalytic enantioselective fluorination of β-keto phosphonates with excellent yield and enantioselectivity in ionic liquid, which simplify product isolation and catalyst recycling. The chemistry of bioactive organofluorine compounds is a rapidly developing area of research because of their importance in biochemical and medicinal application. Chiral organofluorine compounds containing a fluorine atom bonded directly to a stereogenic center have been utilized in studies of enzyme mechanisms and as intermediates in asymmetric syntheses. The development of effective methodologies for the preparation of new selectively fluorinated, stereochemically defined compounds is critical to further advances of fluorine chemistry. The catalytic enantioselective construction of fluorinated stereogenic centers is still important challenge in modern organic chemistry.

  19. EFFECTS OF GLYPHOSATE AMMONIUM SALT ON THE BIOAVAILABLE PHOSPHORUS CONTENT AND THE ACTIVITY OF SELECTED PHOSPHATASES IN LOAMY SAND

    Directory of Open Access Journals (Sweden)

    Maciej Płatkowski

    2015-07-01

    Full Text Available The aim of this study was to determine the effects of glyphosatę ammonium salt on the activity of some enzymes involved in the metabolism of phosphorus in the soil: acid phosphomonoeaterase (EC 3.1.3.2, alkaline phosphomonoeaterase (EC 3.1.3.1, phosphotrieaterase (EC 3.1.5.1, inorganic pyrophosphatase (EC 3.1.6.1, and a phosphorus content in a form available to plants. The experiment was carried out on loamy sand samples with organic carbon content 8.7 g kg-1. Into soil samples the aqueous solutions of Avans Premium 360 SC (360 g glyphosate ammonium salt in 1 dm3 were added. The amount of introduced glyphosate ammonium salt was 0 (control, 1, 10, 50 and 100 mg·kg-1, on days 0 (1 hour after glyphosate application, 7, 14, 28 and 56 measured parameters were determined spectrophotometrically. The obtained results showed that the application of glyphosate ammonium salt resulted in changes of available phosphorus content and the activity of enzymes involved in the metabolism of this element in loamy sand. The effects glyphosate ammonium salt dosage and effect of day of experiment were ambiguous. Among the determined parameters the most sensitive to the presence of the glyphosate ammonium was alkaline phosphomonoesterase.

  20. ROOT ANATOMICAL PLASTICITY IN RESPONSE TO SALT STRESS UNDER REAL AND FULL-SEASON FIELD CONDITIONS AND DETERMINATION OF NEW ANATOMIC SELECTION CHARACTERS FOR BREEDING SALT-RESISTANT RICE (Oryza sativa L.

    Directory of Open Access Journals (Sweden)

    Mehmet AYBEKE

    2016-12-01

    Full Text Available Specific understanding of root anatomy plasticity under salt stress is lacking and requires creation of efficient screening techniques for stress condition s. To fill this gap, this study aimed to determine the anatomical plasticity in root chracteristics of 31 different rice cultivars (from ‘Best’ to ‘Low’ yielding grown under real field conditions (saline and non-saline from planting to harvesting and to reveal detailed root anatomical parameters that can be used to select and breed salt-tolerant rice. Anatomical and histochemical features of all cultivars and thin structures of the apoplastic barriers were investigated. The amount of silica (Si, 35 different anatomical characteristics, anatomical plasticity characteristics, plasticity rates, plasticity trends and changes and strategies of each group under saline and non-saline conditions were compared. The results showed that protective anatomical characters improved/remained equal to, and worsened/remained equal to those of the controls, in the ‘Best’ and other groups, respectively, from non-saline to saline conditions. Anatomical plasticity is essentially directly related to apoplastic barrier features. High genotypic variation was observed in root anatomy in all cultivars, but foremost traits were as follows: (1 cell size, (2 Si presence, (3 Si accumulation shape, (4 Si distribution towards root stele, (5 xylem arch features, (6 lignification-suberization properties in apoplastic barriers and their degrees, (7 presence/absence of idioblast cells filled with gummic and phenolic substances and (8 moderate anatomical plasticity. Cultivars with the most stabile anatomy under saline and non-saline conditions should be used to select and breed salt-resistant rice.

  1. Applications of Fluorine in Medicinal Chemistry.

    Science.gov (United States)

    Gillis, Eric P; Eastman, Kyle J; Hill, Matthew D; Donnelly, David J; Meanwell, Nicholas A

    2015-11-12

    The role of fluorine in drug design and development is expanding rapidly as we learn more about the unique properties associated with this unusual element and how to deploy it with greater sophistication. The judicious introduction of fluorine into a molecule can productively influence conformation, pKa, intrinsic potency, membrane permeability, metabolic pathways, and pharmacokinetic properties. In addition, (18)F has been established as a useful positron emitting isotope for use with in vivo imaging technology that potentially has extensive application in drug discovery and development, often limited only by convenient synthetic accessibility to labeled compounds. The wide ranging applications of fluorine in drug design are providing a strong stimulus for the development of new synthetic methodologies that allow more facile access to a wide range of fluorinated compounds. In this review, we provide an update on the effects of the strategic incorporation of fluorine in drug molecules and applications in positron emission tomography.

  2. Preparation of a Highly Fluorophilic Phosphonium Salt and its Use in a Fluorous Anion-Exchanger Membrane with High Selectivity for Perfluorinated Acids

    Science.gov (United States)

    Boswell, Paul G.; Anfang, Alyce C.; Bühlmann, Philippe

    2008-01-01

    Fluorous solvents are the most nonpolar, nonpolarizable phases known, whereas ions are inherently polar. This makes it difficult to create salts that are soluble in a fluorous solvent. Here we present the synthesis and characterization of a new fluorophilic phosphonium salt, tris{3,5-bis[(perfluorooctyl)propyl]phenyl}methylphosphonium methyl sulfate. The salt has a solubility of at least 14 mM in perfluoro(perhydrophenanthrene), perfluoro(methylcyclohexane), and perfluorohexanes. It also shows immediate potential for use as a phase-transfer catalyst in fluorous biphasic catalysis, but in this work it is used as an anion exchanger site in the first potentiometric fluorous-membrane anion-selective electrode. The membrane sensor exhibited the exceptional selectivity of 3.9 × 1010 to 1 for perfluorooctanesulfonate over chloride, and of 2.5 × 107 to 1 for perfluorooctanoate over chloride. With improvements to the sensor’s detection limit and lifetime, it has the potential to be an attractive alternative to the expensive, time-consuming methods currently employed for measurement of perfluorinated acids. PMID:22072222

  3. Macroscale tribological properties of fluorinated graphene

    Science.gov (United States)

    Matsumura, Kento; Chiashi, Shohei; Maruyama, Shigeo; Choi, Junho

    2018-02-01

    Because graphene is carbon material and has excellent mechanical characteristics, its use as ultrathin lubrication protective films for machine elements is greatly expected. The durability of graphene strongly depends on the number of layers and the load scale. For use in ultrathin lubrication protective films for machine elements, it is also necessary to maintain low friction and high durability under macroscale loads in the atmosphere. In this study, we modified the surfaces of both monolayer and multilayer graphene by fluorine plasma treatment and examined the friction properties and durability of the fluorinated graphene under macroscale load. The durability of both monolayer and multilayer graphene improved by the surface fluorination owing to the reduction of adhesion forces between the friction interfaces. This occurs because the carbon film containing fluorine is transferred to the friction-mating material, and thus friction acts between the two carbon films containing fluorine. On the other hand, the friction coefficient decreased from 0.20 to 0.15 by the fluorine plasma treatment in the multilayer graphene, whereas it increased from 0.21 to 0.27 in the monolayer graphene. It is considered that, in the monolayer graphene, the change of the surface structure had a stronger influence on the friction coefficient than in the multilayer graphene, and the friction coefficient increased mainly due to the increase in defects on the graphene surface by the fluorine plasma treatment.

  4. Synthesis of Regiospecifically Fluorinated Conjugated Dienamides

    Directory of Open Access Journals (Sweden)

    Mohammad Chowdhury

    2014-04-01

    Full Text Available Modular synthesis of regiospecifically fluorinated 2,4-diene Weinreb amides, with defined stereochemistry at both double bonds, was achieved via two sequential Julia-Kocienski olefinations. In the first step, a Z-a-fluorovinyl Weinreb amide unit with a benzothiazolylsulfanyl substituent at the allylic position was assembled. This was achieved via condensation of two primary building blocks, namely 2-(benzo[d]thiazol-2-ylsulfonyl-2-fluoro-N-methoxy-N-methylacetamide (a Julia-Kocienski olefination reagent and 2-(benzo[d]thiazol-2-ylthioacetaldehyde (a bifunctional building block. This condensation was highly Z-selective and proceeded in a good 76% yield. Oxidation of benzothiazolylsulfanyl moiety furnished a second-generation Julia-Kocienski olefination reagent, which was used for the introduction of the second olefinic linkage via DBU-mediated condensations with aldehydes, to give (2Z,4E/Z-dienamides in 50%–74% yield. Although olefinations were 4Z-selective, (2Z,4E/Z-2-fluoro-2,4-dienamides could be readily isomerized to the corresponding 5-substituted (2Z,4E-2-fluoro-N-methoxy-N-methylpenta-2,4-dienamides in the presence of catalytic iodine.

  5. Neurite outgrowth on fluorinated polyimide film micropatterned by ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Okuyama, Y.; Sato, M.; Nagaoka, S.; Kawakami, H. E-mail: kawakami-hiroyoshi@c.metro-u.ac.jp; Suzuki, Y.; Iwaki, M

    2003-05-01

    In this study, we investigated neurite outgrowth on a fluorinated polyimide film micropatterned by ion irradiation. We used the fluorinated polyimide because of its excellent thermal and mechanical properties and biocompatibility. Rattus norvegicus chromaphin (PC12) cells were used for in vitro studies. The polyimide films were irradiated with He{sup +}, Ne{sup +} or Kr{sup +} at 1 x 10{sup 14} ions/cm{sup 2} using an ion-beam mask. The lines in the mask were 120 and 160 {mu}m wide and 120-160 {mu}m apart. PC12 cells were selectively adhered on the polyimide film micropatterned by Kr{sup +}-irradiation. However, the neurite length on the film irradiated by Kr{sup +} was shorter than that determined in the film irradiated by He{sup +}. On the other hand, neurite outgrowth on the polyimide film micropatterned by He{sup +}-irradiation was at least 100 {mu}m in length. This initial study indicated the enhanced outgrowth of PC12 cells on the fluorinated polyimide film micropatterned by ion irradiation.

  6. Physiological adjustment to salt stress in Jatropha curcas is associated with accumulation of salt ions, transport and selectivity of K+, osmotic adjustment and K+/Na+ homeostasis.

    Science.gov (United States)

    Silva, E N; Silveira, J A G; Rodrigues, C R F; Viégas, R A

    2015-09-01

    This study assessed the capacity of Jatropha curcas to physiologically adjust to salinity. Seedlings were exposed to increasing NaCl concentrations (25, 50, 75 and 100 mm) for 15 days. Treatment without NaCl was adopted as control. Shoot dry weight was strongly reduced by NaCl, reaching values of 35% to 65% with 25 to 100 mm NaCl. The shoot/root ratio was only affected with 100 mm NaCl. Relative water content (RWC) increased only with 100 mm NaCl, while electrolyte leakage (EL) was much enhanced with 50 mm NaCl. The Na(+) transport rate to the shoot was more affected with 50 and 100 mm NaCl. In parallel, Cl(-) transport rate increased with 75 and 100 mm NaCl, while K(+) transport rate fell from 50 mm to 100 mm NaCl. In roots, Na(+) and Cl(-) transport rates fell slightly only in 50 mm (to Na(+)) and 50 and 100 mm (to Cl(-)) NaCl, while K(+) transport rate fell significantly with increasing NaCl. In general, our data demonstrate that J. curcas seedlings present changes in key physiological processes that allow this species to adjust to salinity. These responses are related to accumulation of Na(+) and Cl(-) in leaves and roots, K(+)/Na(+) homeostasis, transport of K(+) and selectivity (K-Na) in roots, and accumulation of organic solutes contributing to osmotic adjustment of the species. © 2015 German Botanical Society and The Royal Botanical Society of the Netherlands.

  7. Exploitation of agro-climatic environment for selection of 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase producing salt tolerant indigenous plant growth promoting rhizobacteria.

    Science.gov (United States)

    Misra, Sankalp; Dixit, Vijay Kant; Khan, Mohammad Haneef; Kumar Mishra, Shashank; Dviwedi, Gyanendra; Yadav, Sumit; Lehri, Alok; Singh Chauhan, Puneet

    2017-12-01

    A comprehensive survey for 09 agro-climatic zones of Uttar Pradesh, India was conducted to isolate and characterize salt tolerant 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase possessing plant growth promoting (PGP) rhizobacteria for salt stress amelioration in rice. Here, we have isolated 1125 bacteria having the ability to tolerate 1M NaCl and out of those, 560 were screened for utilizing ACC as sole nitrogen source. 560 isolates were subjected for bacteria coated seed germination assay under 100mM salt (NaCl) stress resulting to 77 isolates which were further evaluated for seed germination assay, PGP and abiotic stress tolerance ability in vitro. This evaluation revealed 15 potent rhizobacteria representing each agro-climatic zone and salt stress mitigation in vitro. In particular, the biomass obtained for bacteria coated rice seedlings were corroborated with the performance of isolates exhibiting maximum average indole acetic acid (IAA) production respective to the agro-climatic zone. Surprisingly based on 16S rRNA, much of the propitious isolates belonged to same specific epithet exhibited variedly in their characteristics. Overall, Bacillus spp. was explored as dominant genera in toto with highest distribution in Western Plain zone followed by Central zone. Therefore, this study provides a counter-intuitive perspective of selection of native microflora for their multifarious PGP and abiotic stress tolerance abilities based on the agro-climatic zones to empower the establishment and development of more suitable inoculants for their application in agriculture under local stress environments. Copyright © 2017 Elsevier GmbH. All rights reserved.

  8. Special Feature Organo-Fluorine Chemical Science

    OpenAIRE

    Helmut Martin Hügel; Neale Jackson

    2012-01-01

    Fluorine is the 13th most abundant element and, with other fluorine containing functional groups, is a most effective element in biological substances, pharmaceuticals, agrochemicals, liquid crystals, dyes, polymers and a wide range of consumer products. This reflects its resistance to metabolic change due to the strength of the C-F bond providing biological stability and the application of its nonstick-interfacial physical characteristics. Its introduction often remains a synthetic challenge...

  9. Optical waveguide components using fluorinated polyimides

    Science.gov (United States)

    Ishibashi, Shigeki; Takahara, Hideyuki

    1999-10-01

    Polyimides are widely used in electronics as heat-resistant organic materials and are now being studied for possible use in optical components. The fluorinated polyimides developed by NTT have high transparency at telecommunication wavelengths, a controllable index of refraction, and high thermal stability, making them suitable for use in optical communication systems. Here, optical components developed using fluorinated polyimides are reviewed, and the relationships between the material characteristics and the device parameters are discussed.

  10. INNER SALTS

    Science.gov (United States)

    been characterized include: (1) mesomeric phosphonium salts possessing phototropic properties; (2) pentavalent phosphorus compounds; and (3) a...Products that have been characterized include: (1) mesomeric phosphonium salts possessing phototropic properties; (2) pentavalent phosphorus compounds; and (3) a mesomeric inner salt . (Author)...Novel phosphonium and phosphorane compounds ere prepared by a variety of m hods from triphenylphosphine and methylene bromide. Products that have

  11. Selective transport of ions and molecules across layer-by-layer assembled membranes of polyelectrolytes, p-sulfonato-calix[n]arenes and Prussian Blue-type complex salts.

    Science.gov (United States)

    Tieke, Bernd; Toutianoush, Ali; Jin, Wanqin

    2005-11-30

    Our recent studies in the field of ultrathin membranes prepared upon layer-by-layer assembly of various polyionic compounds such as polyelectrolytes, calixarenes and polyelectrolytes, and metal hexacyanoferrate salts such as Prussian Blue are reviewed. It is demonstrated that polyelectrolyte multilayers can be used (a) as nanofiltration and reverse osmosis membranes suitable for water softening and seawater desalination and (b) as molecular sieves and ion sieves for size-selective separation of neutral and charged aromatic compounds. Furthermore, hybrid membranes of p-sulfonato-calixarenes and cationic polyelectrolytes showing specific host-guest interactions with permeating ions are described. The membranes exhibit high selectivities for distinct metal ions. Finally, it is demonstrated that purely inorganic membranes of Prussian Blue (PB) and analogues can be prepared upon multiple sequential adsorption of transition metal cations and hexacyanoferrate anions. Due to the porous lattice of PB, the membranes are useful as ion filters able to separate cesium from sodium ions, for example.

  12. 75 FR 18651 - Mandatory Reporting of Greenhouse Gases: Additional Sources of Fluorinated GHGs

    Science.gov (United States)

    2010-04-12

    ... Protection Agency 40 CFR Part 98 Mandatory Reporting of Greenhouse Gases: Additional Sources of Fluorinated... Greenhouse Gases: Additional Sources of Fluorinated GHGs AGENCY: Environmental Protection Agency (EPA... reporting of fluorinated greenhouse gas (fluorinated GHG) emissions from certain source categories...

  13. Ligand Fluorination to Optimize Preferential Oxidation (PROX) of Carbon Monoxide by Water-Soluble Rhodium Porphyrins

    Science.gov (United States)

    Biffinger, Justin C.; Uppaluri, ShriHarsha; Sun, Haoran

    2011-01-01

    Catalytic, low temperature preferential oxidation (PROX) of carbon monoxide by aqueous [5,10,15,20-tetrakis(4-sulfonatophenyl)-2,3,7,8,12,13,17,18-octafluoroporphyrinato]rhodium(III) tetrasodium salt, (1[Rh(III)]) and [5,10,15,20-tetrakis(3-sulfonato-2,6-difluorophenyl)-2,3,7,8,12,13,17,18-octafluoroporphyrinato]rhodium(III) tetrasodium salt, (2[Rh(III)]) is reported. The PROX reaction occurs at ambient temperature in buffered (4 ≤ pH ≤ 13) aqueous solutions. Fluorination on the porphyrin periphery is shown to increase the CO PROX reaction rate, shift the metal centered redox potentials, and acidify ligated water molecules. Most importantly, β-fluorination increases the acidity of the rhodium hydride complex (pKa = 2.2 ± 0.2 for 2[Rh-D]); the dramatically increased acidity of the Rh(III) hydride complex precludes proton reduction and hydrogen activation near neutral pH, thereby permitting oxidation of CO to be unaffected by the presence of H2. This new fluorinated water-soluble rhodium porphyrin-based homogenous catalyst system permits preferential oxidation of carbon monoxide in hydrogen gas streams at 308 °K using dioxygen or a sacrificial electron acceptor (indigo carmine) as the terminal oxidant. PMID:21949596

  14. Self-Assembled Fluorinated Organogelators for Surface Modification

    Directory of Open Access Journals (Sweden)

    Anilkumar Raghavanpillai

    2012-03-01

    Full Text Available A new class of alkyl- and perfluoroalkyl-containing urea and amide derivatives was synthesized from amino acid derivatives. Most of these compounds showed excellent gelation behavior in organic solvents at low concentrations. A few organogelators selected from the initial screening were used for surface modification of fibrous substrates to create hydrophobic and oleophobic composites. The hydrophobic and oleophobic behaviors of these composites were ascribed to a combination of increased surface roughness and the alkyl/fluorinated functionalities present in the gelator backbone.

  15. Unequivocal experimental evidence for a unified lithium salt-free Wittig reaction mechanism for all phosphonium ylide types: reactions with β-heteroatom-substituted aldehydes are consistently selective for cis-oxaphosphetane-derived products

    OpenAIRE

    Byrne, Peter A.; Gilheany, Declan G.

    2012-01-01

    The true course of the lithium salt-free Wittig reaction has long been a contentious issue in organic chemistry. Herein we report an experimental effect that is common to the Wittig reactions of all of the three major phosphonium ylide classes (non-stabilized, semi-stabilized, and stabilized): there is consistently increased selectivity for cis-oxaphosphetane and its derived products (Z-alkene and erythro-B-hydroxyphosphonium salt) in reactions involving aldehydes bearing heteroatom substitue...

  16. Corrosion testing of selected packaging materials for disposal of high-level waste glass in rock-salt formations

    Energy Technology Data Exchange (ETDEWEB)

    Smailos, E.; Schwarzkopf, W.; Koester, R.; Fiehn, B.; Halm, G. [Kernforschungszentrum Karlsruhe GmbH (DE)

    1991-12-31

    In previous corrosion studies performed in salt brines, unalloyed steels, Ti 99.8-Pd and Hastelloy C4 have proved to be the most promising materials for long-term resistant packagings to be used in heat-generating waste (vitrified HLW, spent fuel) disposal in rock-salt formations. Investigations of the iron-base materials Ni-Resist D2 and D4, cast iron and Si-cast iron have also been carried out in order to complete the results available to date. The three steels (fine-grained steel, low-carbon steel, cast steel) investigated and Ti 99.8-Pd resisted pitting and crevice corrosion as well as stress-corrosion cracking under all test conditions. Gamma dose-rates of 1 Gy/h - 100 Gy/h or H{sub 2}S concentrations in the brines as well as welding and explosion plating did not influence noticeably the corrosion behaviour of the materials. Furthermore, the determined corrosion rates of the steels (50 {mu}m/a-250 {mu}m/a, depending on the test conditions) are intercomparable and imply technically acceptable corrosion allowances for the thick-walled containers discussed. For Ti 99.8-Pd no detectable corrosion was observed. By contrast, Hastelloy C4 proved susceptible to pitting and crevice corrosion at gamme dose-rates higher than 1 Gy/h and in the presence of H{sub 2}S (25 mg/l) in Q-brine. The materials Ni Resist D2 and D4, cast iron and Si-cast iron corroded at negligible rates in the in-situ experiments performed in rock salt/limited amounts of NaCI-brine. Nevertheless, these materials must be ruled out as container materials because they have proved to be susceptible to pitting and intergranular corrosion in previous laboratory studies conducted with MgCI{sub 2}-rich brine (Q-brine) in excess. 15 refs.; 29 figs.; 7 tabs.

  17. Novel Paradigm Supercapacitors V: Significance of Organic Polar Solvents and Salt Identities

    Science.gov (United States)

    2017-06-01

    other applications is generally referred to as ‘organic solvents.’ For our work, we prefer the term ‘polar organic polar solvents’ (OPS) because it...class capacitors are commonly used in 6 low energy demand applications like rectifiers, filters, computer memory and consumer electronic devices...successful salts on the periodic table. Proximity on the periodic table stems from the idea that salts close to the Fluorine , the primary salt used in

  18. 3-O-Methylfunicone, a Selective Inhibitor of Mammalian Y-Family DNA Polymerases from an Australian Sea Salt Fungal Strain

    Directory of Open Access Journals (Sweden)

    Fumio Sugawara

    2009-11-01

    Full Text Available We isolated a pol inhibitor from the cultured mycelia extract of a fungal strain isolated from natural salt from a sea salt pan in Australia, which was identified as 3-O-methylfunicone by spectroscopic analyses. This compound selectively inhibited the activities of mammalian Y-family DNA polymerases (pols (i.e., pols η, ι and κ. Among these pols, human pol κ activity was most strongly inhibited, with an IC50 value of 12.5 μM. On the other hand, the compound barely influenced the activities of the other families of mammalian pols, such as A-family (i.e., pol γ, B-family (i.e., pols α, δ and ε or X-family (i.e., pols β, λ and terminal deoxynucleotidyl transferase, and showed no effect on the activities of fish pol δ, plant pols, prokaryotic pols and other DNA metabolic enzymes, such as calf primase of pol α, human immunodeficiency virus type-1 (HIV-1 reverse transcriptase, human telomerase, T7 RNA polymerase, mouse IMP dehydrogenase (type II, human topoisomerases I and II, T4 polynucleotide kinase or bovine deoxyribonuclease I. This compound also suppressed the growth of two cultured human cancer cell lines, HCT116 (colon carcinoma cells and HeLa (cervix carcinoma cells, and UV-treated HeLa cells exhibited lower clonogenic survival in the presence of inhibitor.

  19. PDC bit selection to drill the Brazilian pre-salt heterogeneous carbonates; Selecao de broca PDC para a perfuracao dos carbonatos heterogeneos do pre-sal brasileiro

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Araken Dumont Ramos; Tocantins, Joao Pedro Tourinho [Schlumberger, Rio de Janeiro, RJ (Brazil)

    2012-07-01

    The well drilling operation to access the oil reserves of the Brazilian pre-salt find their highest challenge in the rock reservoir, which is formed from organic limestone and other sediments, and it can have different heterogeneous features that are hostile to drilling. Those features such as the silica nodules increase the rock formation strength and abrasiveness that together with the PDC bit vibrations generated during the rock cutting reduce the life of the cutting structure to a few meters. Because of these conditions, the development of more stable bits, with very low lateral and torsional vibration levels and with more strength PDC, has been one oil industry challenges to drill the pre-salt limestone with silica. This paper aims to present a dynamic comparative analysis between three PDC bits, called BR1, BR2 and BR3, of different generations, selected to drill a well design in a limestone heterogeneous and homogeneous (without silica nodules). This analysis was performed with dynamic three dimensional finite elements software, which considers the interaction between the bit cutter structure and the rock to be drilled, used to design bits, reamers and BHA (Bottom Hole Assembly). (author)

  20. Reference Gene Selection for Quantitative Real-Time RT-PCR Normalization in Iris. lactea var. chinensis Roots under Cadmium, Lead, and Salt Stress Conditions

    Directory of Open Access Journals (Sweden)

    Chun-Sun Gu

    2014-01-01

    Full Text Available Quantitative real time PCR (RT-qPCR has emerged as an accurate and sensitive method to measure the gene expression. However, obtaining reliable result depends on the selection of reference genes which normalize differences among samples. In this study, we assessed the expression stability of seven reference genes, namely, ubiquitin-protein ligase UBC9 (UBC, tubulin alpha-5 (TUBLIN, eukaryotic translation initiation factor (EIF-5A, translation elongation factor EF1A (EF1α, translation elongation factor EF1B (EF1b, actin11 (ACTIN, and histone H3 (HIS, in Iris. lactea var. chinensis (I. lactea var. chinensis root when the plants were subjected to cadmium (Cd, lead (Pb, and salt stress conditions. All seven reference genes showed a relatively wide range of threshold cycles (Ct values in different samples. GeNorm and NormFinder algorithms were used to assess the suitable reference genes. The results from the two software units showed that EIF-5A and UBC were the most stable reference genes across all of the tested samples, while TUBLIN was unsuitable as internal controls. I. lactea var. chinensis is tolerant to Cd, Pb, and salt. Our results will benefit future research on gene expression in response to the three abiotic stresses.

  1. Selective detection of carbohydrates and their peptide conjugates by ESI-MS using synthetic quaternary ammonium salt derivatives of phenylboronic acids.

    Science.gov (United States)

    Kijewska, Monika; Kuc, Adam; Kluczyk, Alicja; Waliczek, Mateusz; Man-Kupisinska, Aleksandra; Lukasiewicz, Jolanta; Stefanowicz, Piotr; Szewczuk, Zbigniew

    2014-06-01

    We present new tags based on the derivatives of phenylboronic acid and apply them for the selective detection of sugars and peptide-sugar conjugates in mass spectrometry. We investigated the binding of phenylboronic acid and its quaternary ammonium salt (QAS) derivatives to carbohydrates and peptide-derived Amadori products by HR-MS and MS/MS experiments. The formation of complexes between sugar or sugar-peptide conjugates and synthetic tags was confirmed on the basis of the unique isotopic distribution resulting from the presence of boron atom. Moreover, incorporation of a quaternary ammonium salt dramatically improved the efficiency of ionization in mass spectrometry. It was found that the formation of a complex with phenylboronic acid stabilizes the sugar moiety in glycated peptides, resulting in simplification of the fragmentation pattern of peptide-derived Amadori products. The obtained results suggest that derivatization of phenylboronic acid as QAS is a promising method for sensitive ESI-MS detection of carbohydrates and their conjugates formed by non-enzymatic glycation or glycosylation.

  2. Controlled Synthesis of Fluorinated Copolymers with Pendant Sulfonates

    DEFF Research Database (Denmark)

    Dimitrov, Ivaylo; Jankova Atanasova, Katja; Hvilsted, Søren

    2008-01-01

    Novel fluorinated copolymers of different architectures and bearing sulfopropyl groups were synthesized by atom transfer radical polymerization (ATRP) of aromatic fluorinated monomers and two modification reactions performed on the polymer chain - demethylation followed by sulfopropylation. As a ...

  3. Enantioselective Fluorination of Spirocyclic β-Prolinals Using Enamine Catalysis

    DEFF Research Database (Denmark)

    Fjelbye, Kasper; Marigo, Mauro; Clausen, Rasmus Prætorius

    2017-01-01

    A series of spirocyclic carbaldehydes were successfully fluorinated using enamine catalysis, furnishing the corresponding tertiary fluorides in both high yields and enantioselectivities. The fluorinated spirocycles provide a set of novel building blocks interesting from a medicinal chemistry point...

  4. No relationship between the cell surface hydrophobicity of coagulase-negative staphylococci and their ability to adhere onto fluorinated poly(ethylene-propylene)

    NARCIS (Netherlands)

    Brokke, P.; Brokke, P.; Dankert, J.; Hogt, A.H.; Feijen, Jan

    1992-01-01

    The cell surface hydrophobicity of 14 encapsulated and 21 non-encapsulated coagulase-negative staphylococci (CN staph) as determined with the salt aggregation test (SAT) as well as with the xylene-water method ranged widely. Non-encapsulated strains adhered well onto fluorinated

  5. Radiosyntheses using Fluorine-18: the Art and Science of Late Stage Fluorination

    Science.gov (United States)

    Cole, Erin L.; Stewart, Megan N.; Littich, Ryan; Hoareau, Raphael; Scott, Peter J. H.

    2014-01-01

    Positron (β+) emission tomography (PE) is a powerful, noninvasive tool for the in vivo, three-dimensional imaging of physiological structures and biochemical pathways. The continued growth of PET imaging relies on a corresponding increase in access to radiopharmaceuticals (biologically active molecules labeled with short-lived radionuclides such as fluorine-18). This unique need to incorporate the short-lived fluorine-18 atom (t1/2 = 109.77 min) as late in the synthetic pathway as possible has made development of methodologies that enable rapid and efficient late stage fluorination an area of research within its own right. In this review we describe strategies for radiolabeling with fluorine-18, including classical fluorine-18 radiochemistry and emerging techniques for late stage fluorination reactions, as well as labeling technologies such as microfluidics and solid-phase radiochemistry. The utility of fluorine-18 labeled radiopharmaceuticals is showcased through recent applications of PET imaging in the healthcare, personalized medicine and drug discovery settings. PMID:24484425

  6. Synthesis and characterization of fluorinated compounds for industrial applications

    OpenAIRE

    Ceretta, Flavio

    2013-01-01

    The presence of fluorine atoms in the structure of an organic molecule alters in an extraordinary way its physico-chemical properties and the countless applications of organo-fluorine compounds are a strong testimony of it. The unique properties of fluorinated surfaces (low surface tension, dielectric constant, friction coefficient) derive from the particular features of the C-F bond (Chapter 1). Thanks to their exceptionally low intermolecular interactions, fluorinated compounds produ...

  7. Fluorine geochemistry in volcanic rock series

    DEFF Research Database (Denmark)

    Stecher, Ole

    1998-01-01

    A new analytical procedure has been established in order to determine low fluorine concentrations (30–100 ppm F) in igneous rocks, and the method has also proven successful for higher concentrations (100–4000 ppm F). Fluorine has been measured in a series of olivine tholeiites from the Reykjanes...... Peninsula, a tholeiite to rhyolitic rock series from Kerlingarfjöll, central Iceland, and an alkaline rock series from Jan Mayen that ranges from ankaramites to trachytes. Fluorine is not appreciably degassed during extrusion and appears to be insensitive to slight weathering. The olivine tholeiites from...... the Reykjanes Peninsula have F contents of 30–300 ppm and exhibit linear increases proportional to the incompatible elements K, P, and Ti. Such incompatible behaviour for F has been confirmed for the less evolved rocks of the other series. The tholeiites from Kerlingarfjöll (100–2000 ppm F) show a linear...

  8. 40 CFR 721.10146 - Partially fluorinated condensation polymer (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Partially fluorinated condensation... Specific Chemical Substances § 721.10146 Partially fluorinated condensation polymer (generic). (a) Chemical... as partially fluorinated condensation polymer (PMN P-07-87) is subject to reporting under this...

  9. Fluorinated Polyurethane Scaffolds for 19F Magnetic Resonance Imaging

    NARCIS (Netherlands)

    Lammers, Twan; Mertens, Marianne E.; Schuster, Philipp; Rahimi, Khosrow; Shi, Yang; Schulz, Volkmar; Kuehne, Alexander J.C.; Jockenhoevel, Stefan; Kiessling, Fabian

    2017-01-01

    Researchers used fluorinated polyurethane scaffolds for 19F magnetic resonance imaging. They generated a novel fluorinated polymer based on thermoplastic polyurethane (19F -TPU) which possesses distinct properties rendering it suitable for fluorine-based MRI. The 19F -TPU is synthesized from a

  10. Fluorinated Silsesquioxanes: Structure, Solubility, and Wetting (Briefing charts)

    Science.gov (United States)

    2015-08-01

    Charts 3. DATES COVERED (From - To) July 2015-July 2015 4. TITLE AND SUBTITLE FLUORINATED SILSESQUIOXANES: STRUCTURE, SOLUBILITY , AND WETTING...FLUORINATED SILSESQUIOXANES: STRUCTURE, SOLUBILITY , AND WETTING Joseph Mabry, Andrew Guenthner, Scott Iacono, Raymond Campos, Sean Ramirez, Brian Moore...Crystalline solids • Soluble in fluorinated solvents 5DISTRIBUTION A. Approved for public release; distribution unlimited. • Spin-cast surface of FD

  11. Lunar mining of oxygen using fluorine

    Science.gov (United States)

    Burt, Donald M.; Tyburczy, James A.; Roberts, Jeffery J.; Balasubramanian, Rajan

    1992-01-01

    Experiments during the first year of the project were directed towards generating elemental fluorine via the electrolysis of anhydrous molten fluorides. Na2SiF6 was dissolved in either molten NaBF4 or a eutectic (minimum-melting) mixture of KF-LiF-NaF and electrolyzed between 450 and 600 C to Si metal at the cathode and F2 gas at the anode. Ar gas was continuously passed through the system and F2 was trapped in a KBr furnace. Various anode and cathode materials were investigated. Despite many experimental difficulties, the capability of the process to produce elemental fluorine was demonstrated.

  12. Solvent extraction of europium(III) to a fluorine-free ionic liquid phase with a diglycolamic acid extractant

    OpenAIRE

    Rout, Alok; Souza, Ernesto Rezende; Binnemans, Koen

    2014-01-01

    Europium(III) was extracted by bis(2-ethylhexyl)diglycolamic acid (DEHDGA) dissolved in the non-fluorinated ionic liquid tetraoctylammonium dodecyl sulphate, [N8888][DS]. The extraction behaviour of europium(III) was investigated as a function of various parameters: pH, extractant concentration, concentration of the europium(III) ion in the aqueous feed and concentration of the salting-out agent. A comparison was made with extraction of europium(III) by the acidic extractants bis(2-ethylhexyl...

  13. Effect of the fluorination technique on the surface-fluorination patterning of double-walled carbon nanotubes.

    Science.gov (United States)

    Bulusheva, Lyubov G; Fedoseeva, Yuliya V; Flahaut, Emmanuel; Rio, Jérémy; Ewels, Christopher P; Koroteev, Victor O; Van Lier, Gregory; Vyalikh, Denis V; Okotrub, Alexander V

    2017-01-01

    Double-walled carbon nanotubes (DWCNTs) are fluorinated using (1) fluorine F 2 at 200 °C, (2) gaseous BrF 3 at room temperature, and (3) CF 4 radio-frequency plasma functionalization. These have been comparatively studied using transmission electron microscopy and infrared, Raman, X-ray photoelectron, and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. A formation of covalent C-F bonds and a considerable reduction in the intensity of radial breathing modes from the outer shells of DWCNTs are observed for all samples. Differences in the electronic state of fluorine and the C-F vibrations for three kinds of the fluorinated DWCNTs are attributed to distinct local surroundings of the attached fluorine atoms. Possible fluorine patterns realized through a certain fluorination technique are revealed from comparison of experimental NEXAFS F K-edge spectra with quantum-chemical calculations of various models. It is proposed that fluorination with F 2 and BrF 3 produces small fully fluorinated areas and short fluorinated chains, respectively, while the treatment with CF 4 plasma results in various attached species, including single or paired fluorine atoms and -CF 3 groups. The results demonstrate a possibility of different patterning of carbon surfaces through choosing the fluorination method.

  14. Effect of the fluorination technique on the surface-fluorination patterning of double-walled carbon nanotubes

    Directory of Open Access Journals (Sweden)

    Lyubov G. Bulusheva

    2017-08-01

    Full Text Available Double-walled carbon nanotubes (DWCNTs are fluorinated using (1 fluorine F2 at 200 °C, (2 gaseous BrF3 at room temperature, and (3 CF4 radio-frequency plasma functionalization. These have been comparatively studied using transmission electron microscopy and infrared, Raman, X-ray photoelectron, and near-edge X-ray absorption fine structure (NEXAFS spectroscopy. A formation of covalent C–F bonds and a considerable reduction in the intensity of radial breathing modes from the outer shells of DWCNTs are observed for all samples. Differences in the electronic state of fluorine and the C–F vibrations for three kinds of the fluorinated DWCNTs are attributed to distinct local surroundings of the attached fluorine atoms. Possible fluorine patterns realized through a certain fluorination technique are revealed from comparison of experimental NEXAFS F K-edge spectra with quantum-chemical calculations of various models. It is proposed that fluorination with F2 and BrF3 produces small fully fluorinated areas and short fluorinated chains, respectively, while the treatment with CF4 plasma results in various attached species, including single or paired fluorine atoms and –CF3 groups. The results demonstrate a possibility of different patterning of carbon surfaces through choosing the fluorination method.

  15. Selective and effective binding of pillar[5,6]arenes toward secondary ammonium salts with a weakly coordinating counteranion.

    Science.gov (United States)

    Li, Chunju; Shu, Xiaoyan; Li, Jian; Fan, Jiazeng; Chen, Zhenxia; Weng, Linhong; Jia, Xueshun

    2012-08-17

    The selective and effective binding of secondary ammoniums with a weakly coordinating tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (BArF) counteranion by per-ethylated pillar[5,6]arenes is reported. The construction of a first pillararene-based self-sorting system consisting of two wheels and two axles is also described.

  16. Fluorine and Fluorinated Motifs in the Design and Application of Bioisosteres for Drug Design.

    Science.gov (United States)

    Meanwell, Nicholas A

    2018-02-05

    The electronic properties and relatively small size of fluorine endow it with considerable versatility as a bioisostere and it has found application as a substitute for lone pairs of electrons, the hydrogen atom, and the methyl group while also acting as a functional mimetic of the carbonyl, carbinol, and nitrile moieties. In this context, fluorine substitution can influence the potency, conformation, metabolism, membrane permeability, and P-gp recognition of a molecule and temper inhibition of the hERG channel by basic amines. However, as a consequence of the unique properties of fluorine, it features prominently in the design of higher order structural metaphors that are more esoteric in their conception and which reflect a more sophisticated molecular construction that broadens biological mimesis. In this Perspective, applications of fluorine in the construction of bioisosteric elements designed to enhance the in vitro and in vivo properties of a molecule are summarized.

  17. Fluorine effect on pericyclic and pseudopericyclic processes ...

    Indian Academy of Sciences (India)

    Administrator

    Magnetic susceptibility aniso- tropy (Δχaniso), NICS(0), NBO and bond critical property (BCP) analyses clearly illustrate the following; .... Fluorine effect on pericyclic and pseudopericyclic processes: evidences from ab initio theory. 861. Figure 2. Relative Free ... Thermochemical parameters of the reactions. 1–6 computed at ...

  18. Structural phase stability in fluorinated calcium hydride

    Science.gov (United States)

    Varunaa, R.; Ravindran, P.

    2017-05-01

    In order to improve the hydrogen storage properties of calcium hydride (CaH2), we have tuned its thermodynamical properties through fluorination. Using ab-initio total energy calculations based on density functional theory, the structural stability, electronic structure and chemical bonding of CaH2-xFx systems are investigated. The phase transition of fluorinated systems from orthorhombic to cubic structure has been observed at 18% fluorine doped CaH2. The phase stability analysis shows that CaH2-xFx systems are highly stable and the stability is directly correlating with their ionicity. Density of states (DOS) plot reveals that CaH2-xFx systems are insulators. Partial DOS and charge density analyses conclude that these systems are governed by ionic bonding. Our results show that H closer to F can be removed more easily than that far away from F and this is due to disproportionation induced in the bonding interaction by fluorination.

  19. Self-lubricating fluorine shaft seal material

    Science.gov (United States)

    Munk, W. R.

    1970-01-01

    Lubricating film is produced by a reaction of fluorine with a composite of aluminum oxide and nickel powder. The rate of nickel fluoride generation is proportional to the rate at which the fluoride is rubbed off the surface, allowing the seal to operate with the lowest possible heating.

  20. Fluorine effect on pericyclic and pseudopericyclic processes ...

    Indian Academy of Sciences (India)

    ... (reaction 4) corresponds to a borderline case; 2-pyranol (3) and pyran (5) and 6-fluoro pyran (6) reactions are clearly pericyclic in character. Correspondingly pseudeopericyclic reactions show up orbital disconnections and fluorine delays the occurrence of orbital disconnections on the reaction trajectory.

  1. Synthesis of Fluorinated Polymers and Evaluation of Wettability

    Directory of Open Access Journals (Sweden)

    Tamami Kimura

    2016-03-01

    Full Text Available Two kinds of fluorinated polymers were synthesized: an acrylate polymer having a fluorinated triethylene glycol as a pendant group (2a and a fluoroalkyl acrylate polymer (2b. The contact angle of these fluorinated polymers against water, non-fluorinated alcohols and fluorinated alcohols were evaluated. As compared with the fluoroalkyl polymer (2b, fluoroethylene glycol polymer (2a showed smaller contact angle against water and non-fluorinated alcohols. This supports the proposition that changing the alkyl chain into the ethylene glycol-type chain gave some interaction between etheric oxygen and water or non-fluorinated alcohols. In addition, fluoroalkyl acrylate polymer (2b showed remarkably low values of critical surface tension.

  2. Deciphering the Fluorine Code-The Many Hats Fluorine Wears in a Protein Environment.

    Science.gov (United States)

    Berger, Allison Ann; Völler, Jan-Stefan; Budisa, Nediljko; Koksch, Beate

    2017-09-19

    Deciphering the fluorine code is how we describe not only the focus of this Account, but also the systematic approach to studying the impact of fluorine's incorporation on the properties of peptides and proteins used by our groups and others. The introduction of fluorine has been shown to impart favorable, but seldom predictable, properties to peptides and proteins, but up until about two decades ago the outcomes of fluorine modification of peptides and proteins were largely left to chance. Driven by the motivation to extend the application of the unique properties of the element fluorine from medicinal and agro chemistry to peptide and protein engineering we have established extensive research programs that enable the systematic investigation of effects that accompany the introduction of fluorine into this class of biopolymers. The introduction of fluorine into amino acids offers a universe of options for modifications with regard to number and position of fluorine substituents in the amino acid side chain. Moreover, it is important to emphasize that the consequences of incorporating the C-F bond into a biopolymer can be attributed to two distinct yet related phenomena: (i) the fluorine substituent can directly engage in intermolecular interactions with its environment and/or (ii) the other functional groups present in the molecule can be influenced by the electron withdrawing nature of this element (intramolecular) and in turn interact differently with their immediate environment (intermolecular). Based on our studies, we have shown that a change in number and/or position of as subtle as one single fluorine substituent has the power to considerably modify key properties of amino acids such as hydrophobicity, polarity, and secondary structure propensity. These properties are crucial factors in peptide and protein engineering, and thus, fluorinated amino acids can be applied to fine-tune properties such as protein folding, proteolytic stability, and protein

  3. Fluorine content in the soft tissues, blood and milk of ruminants outside and inside fluorine emission areas

    Energy Technology Data Exchange (ETDEWEB)

    Oelschlaeger, W.; Feyler, L.; Schwarz, E.

    1972-01-01

    Data on the fluorine content of soft tissues, blood and milk inside and outside fluorine emission areas vary widely, probably because of analytical difficulties. Possible errors and their elimination are discussed. A large number of analyses was carried out to determine the fluorine content of heart, liver, lung, kidney, adrenal, muscle, spleen, pancreas, lymph nodes, thyroid, thymus, pituitary and cerebrum and cerebellum of cows and calves, as well as 388 milk samples and 232 blood samples. In calves born from cows kept for 3 1/2 years near a factory producing hydrofluoric acid, there was a clear relationship between the fluorine content during the suckling and drinking period, and also in a still-born calf, with the fluorine uptake of the dam during the months of pregnancy. In contrast to cattle, calves showed significantly higher fluorine levels in the adrenals compared with the kidneys. The soft tissues of cattle outside the fluorine emission areas contained more fluorine than in calves within the emission areas. Fluorine accumulation in liver, lung, kidney, cerebrum and cerebellum, thyroid and pituitary was markedly raised in animals with high fluorine uptake, whereas there was no significant change in the levels in the heart, musculature and spleen. So far as human health is concerned, the raised fluorine level in milk was significantly below the maximum level permitted in fluoridated drinking water.

  4. Salt cookbook

    CERN Document Server

    Saha, Anirban

    2015-01-01

    If you are a professional associated with system and infrastructure management, looking at automated infrastructure and deployments, then this book is for you. No prior experience of Salt is required.

  5. Polarity, selectivity and performance of hydrophilic organic/salt-containing aqueous two-phase system on counter-current chromatography for polar compounds.

    Science.gov (United States)

    Liu, Dan; Hong, Zhilai; Gao, Mingzhe; Wang, Zhixin; Gu, Ming; Zhang, Xiaozhe; Xiao, Hongbin

    2016-05-27

    The essential attributes of a solvent system for separation polar compounds on CCC are polarity, selectively and performance. Here, hydrophilic organic/salt-containing aqueous two-phase system (HO/S TPS) was evaluated as an alternative solvent system for CCC separation of polar compounds. Polarity measurements based on Rohrschneider-Snyder parameter was developed as quantitative assessing the polarity of HO/S TPS and comparing with an organic/aqueous system. All investigated 1-butanol/ethanol/saturated ammonium sulfate solution/water (BEAsWat) and 1-butanol/ethanol/saturated dipotassium hydrogen phosphate solution/water (BEDhpWat) systems with polarity values of organic phase from 4.5 to 6.8, were more polar than chloroform/methanol/water (1/1/1). The considerable water content of BEAsWat and BEDhpWat (0/1/1/1/) was 45.4 and 42.6% (w%) of hydrophilic organic phase, and 66.4 and 51.2% (w%) of salt-containing aqueous phase, respectively, closed to conventional aqueous two-phase system. Therefore, the polarity of HO/S TPS is in the middle of organic/aqueous and aqueous two-phase system. The LogKC values of twenty four polar compounds as model mixture confirmed that the polarities of HO/S TPSs were matched to that of the polar compounds and shown to be a very selective technique capable of separating positional isomers. Moreover, BEAsWat and BEDhpWat systems can be easily retained in CCC column with suitable elution mode. The hydrodynamic behavior reversion of HO/S TPS on hydrodynamic CCC was observed and was tentatively explained based on the density difference. Finally, caffeoylquinic acid isomers and dihydroxybenzoic acid isomers were successfully separated with HO/S TPS on CCC, respectively. Those results demonstrate that HO/S TPS on CCC is a performant and stable way to separate polar compounds from natural products. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. High Cytotoxic Activity of Phosphonium Salts and Their Complementary Selectivity towards HeLa and K562 Cancer Cells: Identification of Tri-n-butyl-n-hexadecylphosphonium bromide as a Highly Potent Anti-HeLa Phosphonium Salt.

    Science.gov (United States)

    Bachowska, Barbara; Kazmierczak-Baranska, Julia; Cieslak, Marcin; Nawrot, Barbara; Szczęsna, Dorota; Skalik, Joanna; Bałczewski, Piotr

    2012-02-01

    Quaternary ammonium and phosphonium salts have been screened for their toxic effect on HeLa and K562 cancer cell lines, as well as on normal HUVEC cells. Tri-n-butyl-n-hexadecylphosphonium bromide, the first phosphonium salt with a halogen anion tested against HeLa cells, was 12 times more potent (IC50 phosphonium salt to be evaluated in HeLa cells. However, it was inactive against K562 cells (24 and 48 h). According to a caspase-3/7 assay, its toxicity has not been connected with the induction of apoptosis. In contrast, triphenylalkylphosphonium iodides with shorter C1-5 alkyl chains were inactive against HeLa cells but very active against K562 cells (IC50=6-10 μm after 48 h). Phosphonium cations with halide counterions proved to be more potent than those with (CF3SO2)2N(-) as the anion, as in the anticancer agent NSC 747251, or other anions in molecules with similar alkyl chain lengths. On the other hand, a series of ammonium salts containing a short methylthiomethyl or methoxymethyl side chain revealed low cytotoxicity (IC50 >500 μm after 24 and 48 h) against both HeLa and K562 cancer cell lines as well as normal HUVEC cells, showing that the nontoxic N(+)CH2YMe (Y=S, O) structural motif in ammonium salts could be suitable for further optimization and development, especially in transfection experiments.

  7. Maintenance of Mouse Gustatory Terminal Field Organization Is Disrupted following Selective Removal of Peripheral Sodium Salt Taste Activity at Adulthood.

    Science.gov (United States)

    Skyberg, Rolf; Sun, Chengsan; Hill, David L

    2017-08-09

    Neural activity plays a critical role in the development of central circuits in sensory systems. However, the maintenance of these circuits at adulthood is usually not dependent on sensory-elicited neural activity. Recent work in the mouse gustatory system showed that selectively deleting the primary transduction channel for sodium taste, the epithelial sodium channel (ENaC), throughout development dramatically impacted the organization of the central terminal fields of three nerves that carry taste information to the nucleus of the solitary tract. More specifically, deleting ENaCs during development prevented the normal maturation of the fields. The present study was designed to extend these findings by testing the hypothesis that the loss of sodium taste activity impacts the maintenance of the normal adult terminal field organization in male and female mice. To do this, we used an inducible Cre-dependent genetic recombination strategy to delete ENaC function after terminal field maturation occurred. We found that removal of sodium taste neural activity at adulthood resulted in significant reorganization of mature gustatory afferent terminal fields in the nucleus of the solitary tract. Specifically, the chorda tympani and greater superficial petrosal nerve terminal fields were 1.4× and 1.6× larger than age-matched controls, respectively. By contrast, the glossopharyngeal nerve, which is not highly sensitive to sodium taste stimulation, did not undergo terminal field reorganization. These surprising results suggest that gustatory nerve terminal fields remain plastic well into adulthood, which likely impacts central coding of taste information and taste-related behaviors with altered taste experience. SIGNIFICANCE STATEMENT Neural activity plays a major role in the development of sensory circuits in the mammalian brain. However, the importance of sensory-driven activity in maintaining these circuits at adulthood, especially in subcortical structures, appears to be

  8. Fluorination of phthalocyanine substituents: Improved photoproperties and enhanced photodynamic efficacy after optimal micellar formulations.

    Science.gov (United States)

    Pucelik, Barbara; Gürol, Ilke; Ahsen, Vefa; Dumoulin, Fabienne; Dąbrowski, Janusz M

    2016-11-29

    A fluorinated phthalocyanine and its non-fluorinated analogue were selected to evaluate the potential enhancement of fluorination on photophysical, photochemical and redox properties as well as on biological activity in cellular and animal models. Due to the pharmacological relevance, the affinity of these phthalocyanines towards biological membranes (logPow) as well as their primary interaction with human serum albumin (HSA) or low-density lipoprotein (LDL) were determined. Water-dispersible drug formulation of phthalocyanines via Pluronic(®)-based triblock copolymer micelles was prepared to avoid self-aggregation effects and to improve their delivery. The obtained results demonstrate that phthalocyanines incorporation into tunable-polymeric micelles significantly enhanced their cellular uptake and their photocytotoxicity. The improved biodistribution and photodynamic efficacy of the phthalocyanines-triblock copolymer conjugates was also confirmed in vivo in CT26 bearing BALB/c mice. PDT with both compounds led to tumor growth inhibition in all treated animals. Fluorinated phthalocyanine 2 turned out to be the most effective anticancer agent as the tumors of 20% of mice treated regressed completely and did not appear for over one year after treatment. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  9. Chemoselective fluorination and chemoinformatic analysis of griseofulvin: Natural vs fluorinated fungal metabolites.

    Science.gov (United States)

    Paguigan, Noemi D; Al-Huniti, Mohammed H; Raja, Huzefa A; Czarnecki, Austin; Burdette, Joanna E; González-Medina, Mariana; Medina-Franco, José L; Polyak, Stephen J; Pearce, Cedric J; Croatt, Mitchell P; Oberlies, Nicholas H

    2017-10-15

    Griseofulvin is a fungal metabolite and antifungal drug used for the treatment of dermatophytosis in both humans and animals. Recently, griseofulvin and its analogues have attracted renewed attention due to reports of their potential anticancer effects. In this study griseofulvin (1) and related analogues (2-6, with 4 being new to literature) were isolated from Xylaria cubensis. Six fluorinated analogues (7-12) were synthesized, each in a single step using the isolated natural products and Selectflour, so as to examine the effects of fluorine incorporation on the bioactivities of this structural class. The isolated and synthesized compounds were screened for activity against a panel of cancer cell lines (MDA-MB-435, MDA-MB-231, OVCAR3, and Huh7.5.1) and for antifungal activity against Microsporum gypseum. A comparison of the chemical space occupied by the natural and fluorinated analogues was carried out by using principal component analysis, documenting that the isolated and fluorinated analogues occupy complementary regions of chemical space. However, the most active compounds, including two fluorinated derivatives, were centered around the chemical space that was occupied by the parent compound, griseofulvin, suggesting that modifications must preserve certain attributes of griseofulvin to conserve its activity. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  10. Effects of fluorine on the human fetus

    Energy Technology Data Exchange (ETDEWEB)

    He, H.; Cheng, Z.S.; Liu, W.Q. [Huaxi Medical University, Huaxi (China)

    2008-10-15

    In an endemic fluorosis area, 16 fetuses that were delivered during their sixth to eighth month of gestation by means of artificial abortion were collected and studied. The results (compared to 10 control fetuses from a non-endemic area) show that fluorine levels in tissues are obviously high, especially in brain, calvarium, and femur. The activity of alkaline phosphatase in femur and kidney was raised. By observation of the ultrastructure of samples, the number of mitochondria, rough-surfaced endoplasmic reticulum, and free ribosome in neurons of cerebral cortex were reduced, and the rough-surfaced endoplasmic reticulum was obviously dilated. These findings indicate that the neurons of the cerebral cortex in the developing brain may be one of the targets of fluorine.

  11. Complete mapping of the morphologies of some linear and graft fluorinated co-oligomers in an aprotic solvent by dissipative particle dynamics

    OpenAIRE

    Özen, Alimet Sema; Ozen, Alimet Sema; Şen, Ünal; Sen, Unal; Atılgan, Canan; Atilgan, Canan

    2006-01-01

    The mesoscopic morphologies of linear and graft fluorinated block copolymers of ABCBA and C:BA types, respectively, have been investigated by using dissipative particle dynamics method. Self-assembly in a selective solvent has been examined by the introduction of dimethylformamide as the choice of solvent. By comparing the solubility parameters calculated using atomistic simulations, fluorine-containing segments are found to be immiscible both with other segments of the polymer and with the s...

  12. Quantification of Fluorine Content in AFFF Concentrates

    Science.gov (United States)

    2017-09-29

    for MilSpec compliance. Fluorocarbon surfactants are the most active components in these concentrates, and analysis of the fluorine content in the...situation as warming or cooling the sample does not affect the spectrum. The next most affected resonance is the one originating from the -CF2...Mabury, Environ. Chem. 2013, 10, 486-493. 9. T.J. Martin, “Fire-Fighting Foam Technology,” in Foam Engineering : Fundamentals and Applications; P

  13. Spectrophotometric determination of fluorine in silicate rocks

    Science.gov (United States)

    Peck, L.C.; Smith, V.C.

    1964-01-01

    The rock powder is sintered with a sodium carbonate flux containing zinc oxide and magnesium carbonate, the sinter-cake leached with water and the resulting solution filtered. Fluorine is separated from the acidified filtrate by steam distillation and determined spectrophotometrically by means of a zirconium-SPADNS reagent. If a multiple-unit distillation apparatus is used, 12 determinations can be completed per man-day. ?? 1964.

  14. Direct Synthesis of Fluorinated Heteroarylether Bioisosteres

    Science.gov (United States)

    Zhou, Qianghui; Ruffoni, Alessandro; Gianatassio, Ryan; Fujiwara, Yuta; Sella, Eran; Shabat, Doron

    2013-01-01

    This work delineates a method for the modular synthesis of reagents that are capable of direct incorporation of difluoroalkyl groups onto heterocycles. The scope and generality of this method is exemplified with the difluoroethyl group (along with the introduction of a new reagent for difluoroethylation, DFES-Na) and a proof of principle is shown for a general synthesis of fluorinated heteroarylether bioisosteres. PMID:23460402

  15. Organometallic chemistry using partially fluorinated benzenes.

    Science.gov (United States)

    Pike, Sebastian D; Crimmin, Mark R; Chaplin, Adrian B

    2017-03-28

    Fluorobenzenes, in particular fluorobenzene (FB) and 1,2-difluorobenzene (1,2-DiFB), are increasingly becoming recognised as versatile solvents for conducting organometallic chemistry and transition-metal-based catalysis. The presence of fluorine substituents reduces the ability to donate π-electron density from the arene and consequently fluorobenzenes generally bind weakly to metal centres, allowing them to be used as essentially non-coordinating solvents or as readily displaced ligands. In this context, examples of well-defined complexes of fluorobenzenes are discussed, including trends in binding strength with increasing fluorination and different substitution patterns. Compared to more highly fluorinated benzenes, FB and 1,2-DiFB typically demonstrate greater chemical inertness, however, C-H and C-F bond activation reactions can be induced using appropriately reactive transition metal complexes. Such reactions are surveyed, including catalytic examples, not only to provide perspective for the use of FB and 1,2-DiFB as innocent solvent media, but also to highlight opportunities for their exploitation in contemporary organic synthesis.

  16. Fluorine-functionalized ionic liquids with high oxygen solubility

    OpenAIRE

    Vanhoutte, Gijs; Hojniak, Sandra; Bardé, Fanny; Binnemans, Koen; Fransaer, Jan

    2018-01-01

    Eight fluorine-functionalized ionic liquids were synthesized and the oxygen solubility was compared to commercial ionic liquids without the extra fluorinated chain. The concentration of dissolved oxygen increased with the fluorine content of the alkyl chain, which can be attached either to the cation or the anion. This approach maintains the freedom to design an ionic liquid for a specific application, while at the same time the oxygen solubility is increased.

  17. Reactions of gem-Difluorinated Phosphonium Salts Induced by Light.

    Science.gov (United States)

    Panferova, Liubov I; Tsymbal, Artem V; Levin, Vitalij V; Struchkova, Marina I; Dilman, Alexander D

    2016-03-04

    gem-Difluorinated phosphonium salts, which are readily obtained from aldehydes and difluoromethylene phosphobetaine, can serve as a source of radicals under reductive conditions. An iridium complex or Hantzsch ester was used as a one-electron reducing agent when irradiated with visible light. The fluorinated radicals were trapped with various alkenes, leading to products either via a photoredox cycle (for the iridium catalyst) or via a hydrogen atom transfer (for the Hantzsch ester).

  18. 75 FR 74773 - Mandatory Reporting of Greenhouse Gases: Additional Sources of Fluorinated GHGs

    Science.gov (United States)

    2010-12-01

    ... Protection Agency 40 CFR Part 98 Mandatory Reporting of Greenhouse Gases: Additional Sources of Fluorinated... Greenhouse Gases: Additional Sources of Fluorinated GHGs AGENCY: Environmental Protection Agency (EPA... greenhouse gas emissions from additional sources of fluorinated greenhouse gases, including electronics...

  19. Fluorinated tripodal receptors for potentiometric chloride detection in biological fluids.

    Science.gov (United States)

    Pankratova, Nadezda; Cuartero, Maria; Jowett, Laura A; Howe, Ethan N W; Gale, Philip A; Bakker, Eric; Crespo, Gastón A

    2018-01-15

    Fluorinated tripodal compounds were recently reported to be efficient transmembrane transporters for a series of inorganic anions. In particular, this class of receptors has been shown to be suitable for the effective complexation of chloride, nitrate, bicarbonate and sulfate anions via hydrogen bonding. The potentiometric properties of urea and thiourea-based fluorinated tripodal receptors are explored here for the first time, in light of the need for reliable sensors for chloride monitoring in undiluted biological fluids. The ion selective electrode (ISE) membranes with tren-based tris-urea bis(CF3) tripodal compound (ionophore I) were found to exhibit the best selectivity for chloride over major lipophilic anions such as salicylate ( [Formula: see text] ) and thiocyanate ( [Formula: see text] ). Ionophore I-based ISEs were successfully applied for chloride determination in undiluted human serum as well as artificial serum sample, the slope of the linear calibration at the relevant background of interfering ions being close to Nernstian (49.8±1.7mV). The results of potentiometric measurements were confirmed by argentometric titration. Moreover, the ionophore I-based ISE membrane was shown to exhibit a very good long-term stability of potentiometric performance over the period of 10 weeks. Nuclear magnetic resonance (NMR) titrations, potentiometric sandwich membrane experiments and density functional theory (DFT) computational studies were performed to determine the binding constants and suggest 1:1 complexation stoichiometry for the ionophore I with chloride as well as salicylate. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Fundamental Properties of Salts

    Energy Technology Data Exchange (ETDEWEB)

    Toni Y Gutknecht; Guy L Fredrickson

    2012-11-01

    Thermal properties of molten salt systems are of interest to electrorefining operations, pertaining to both the Fuel Cycle Research & Development Program (FCR&D) and Spent Fuel Treatment Mission, currently being pursued by the Department of Energy (DOE). The phase stability of molten salts in an electrorefiner may be adversely impacted by the build-up of fission products in the electrolyte. Potential situations that need to be avoided, during electrorefining operations, include (i) fissile elements build up in the salt that might approach the criticality limits specified for the vessel, (ii) electrolyte freezing at the operating temperature of the electrorefiner due to changes in the liquidus temperature, and (iii) phase separation (non-homogenous solution). The stability (and homogeneity) of the phases can be monitored by studying the thermal characteristics of the molten salts as a function of impurity concentration. Simulated salt compositions consisting of the selected rare earth and alkaline earth chlorides, with a eutectic mixture of LiCl-KCl as the carrier electrolyte, were studied to determine the melting points (thermal characteristics) using a Differential Scanning Calorimeter (DSC). The experimental data were used to model the liquidus temperature. On the basis of the this data, it became possible to predict a spent fuel treatment processing scenario under which electrorefining could no longer be performed as a result of increasing liquidus temperatures of the electrolyte.

  1. Comparison of topotactic fluorination methods for complex oxide films

    Directory of Open Access Journals (Sweden)

    E. J. Moon

    2015-06-01

    Full Text Available We have investigated the synthesis of SrFeO3−αFγ (α and γ ≤ 1 perovskite films using topotactic fluorination reactions utilizing poly(vinylidene fluoride as a fluorine source. Two different fluorination methods, a spin-coating and a vapor transport approach, were performed on as-grown SrFeO2.5 films. We highlight differences in the structural, compositional, and optical properties of the oxyfluoride films obtained via the two methods, providing insight into how fluorination reactions can be used to modify electronic and optical behavior in complex oxide heterostructures.

  2. Geology of barium, strontium, and fluorine deposits in Canada

    National Research Council Canada - National Science Library

    Dawson, K. R

    1985-01-01

    In this report the geochemistry and mineralogy of barium, strontium and fluorine are described, occurrences are delineated and areas and geological conditions favourable for additional occurrences are indicated...

  3. Hydrolytically stable fluorinated metal-organic frameworks for energy-efficient dehydration

    Science.gov (United States)

    Cadiau, Amandine; Belmabkhout, Youssef; Adil, Karim; Bhatt, Prashant M.; Pillai, Renjith S.; Shkurenko, Aleksander; Martineau-Corcos, Charlotte; Maurin, Guillaume; Eddaoudi, Mohamed

    2017-05-01

    Natural gas must be dehydrated before it can be transported and used, but conventional drying agents such as activated alumina or inorganic molecular sieves require an energy-intensive desiccant-regeneration step. We report a hydrolytically stable fluorinated metal-organic framework, AlFFIVE-1-Ni (KAUST-8), with a periodic array of open metal coordination sites and fluorine moieties within the contracted square-shaped one-dimensional channel. This material selectively removed water vapor from gas streams containing CO2, N2, CH4, and higher hydrocarbons typical of natural gas, as well as selectively removed both H2O and CO2 in N2-containing streams. The complete desorption of the adsorbed water molecules contained by the AlFFIVE-1-Ni sorbent requires relatively moderate temperature (~105°C) and about half the energy input for commonly used desiccants.

  4. Hydrolytically stable fluorinated metal-organic frameworks for energy-efficient dehydration

    KAUST Repository

    Cadiau, Amandine

    2017-05-18

    Natural gas must be dehydrated before it can be transported and used, but conventional drying agents such as activated alumina or inorganic molecular sieves require an energy-intensive desiccant-regeneration step. We report a hydrolytically stable fluorinated metal-organic framework, AlFFIVE-1-Ni (KAUST-8), with a periodic array of open metal coordination sites and fluorine moieties within the contracted square-shaped one-dimensional channel. This material selectively removed water vapor from gas streams containing CO2, N2, CH4, and higher hydrocarbons typical of natural gas, as well as selectively removed both H2O and CO2 in N2-containing streams. The complete desorption of the adsorbed water molecules contained by the AlFFIVE-1-Ni sorbent requires relatively moderate temperature (~105°C) and about half the energy input for commonly used desiccants.

  5. Engineering Evaluation of Proposed Alternative Salt Transfer Method for the Molten Salt Reactor Experiement for the Oak Ridge National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Carlberg, Jon A.; Roberts, Kenneth T.; Kollie, Thomas G.; Little, Leslie E.; Brady, Sherman D.

    2009-09-30

    This evaluation was performed by Pro2Serve in accordance with the Technical Specification for an Engineering Evaluation of the Proposed Alternative Salt Transfer Method for the Molten Salt Reactor Experiment at the Oak Ridge National Laboratory (BJC 2009b). The evaluators reviewed the Engineering Evaluation Work Plan for Molten Salt Reactor Experiment Residual Salt Removal, Oak Ridge National Laboratory, Oak Ridge, Tennessee (DOE 2008). The Work Plan (DOE 2008) involves installing a salt transfer probe and new drain line into the Fuel Drain Tanks and Fuel Flush Tank and connecting them to the new salt transfer line at the drain tank cell shield. The probe is to be inserted through the tank ball valve and the molten salt to the bottom of the tank. The tank would then be pressurized through the Reactive Gas Removal System to force the salt into the salt canisters. The Evaluation Team reviewed the work plan, interviewed site personnel, reviewed numerous documents on the Molten Salt Reactor (Sects. 7 and 8), and inspected the probes planned to be used for the transfer. Based on several concerns identified during this review, the team recommends not proceeding with the salt transfer via the proposed alternate salt transfer method. The major concerns identified during this evaluation are: (1) Structural integrity of the tanks - The main concern is with the corrosion that occurred during the fluorination phase of the uranium removal process. This may also apply to the salt transfer line for the Fuel Flush Tank. Corrosion Associated with Fluorination in the Oak Ridge National Laboratory Fluoride Volatility Process (Litman 1961) shows that this problem is significant. (2) Continued generation of Fluorine - Although the generation of Fluorine will be at a lower rate than experienced before the uranium removal, it will continue to be generated. This needs to be taken into consideration regardless of what actions are taken with the salt. (3) More than one phase of material

  6. Engineering development studies for molten-salt breeder reactor processing No. 22

    Energy Technology Data Exchange (ETDEWEB)

    Hightower, J.R. Jr. (comp.)

    1976-06-01

    Processing methods are being developed for use in a close-coupled facility for removing fission products, corrosion products, and fissile materials from the MSBR fuel. This report discusses the autoresistance heating for the continuous fluorinator, the metal transfer experiment, experiments for the salt-metal contactor, and fuel reconstitution. 10 fig. (DLC)

  7. Comparative electrooptic study of new orthoconic liquid crystals with fluorinated alkoxy terminal chains

    Science.gov (United States)

    Spadło, A.; Otón, E.; Dąbrowski, R.; Żurowska, M.; Otón, J. M.; Bennis, N.

    2010-06-01

    Electrooptical properties of several new orthoconic antiferroelectric liquid crystal mixtures with partially fluorinated alkoxyalkoxy terminal chains have been investigated in order to select the best mixture for display applications. Electrooptical studies have been performed on these orthoconic materials aiming at evaluating their static and dynamic performance under passive multiplexing conditions. A number of parameters have been evaluated, static and dynamic contrast, driving scheme for passive multiplexing, rise and fall response times, dynamic range, and dynamic greyscale.

  8. Space charge dynamics Of CF4 fluorinated LDPE samples from different fluorination conditions and their DC conductivities

    Science.gov (United States)

    Liu, Ning; Li, Ziyun; Chen, George; Chen, Qiang; Li, Shengtao

    2017-07-01

    Taking advantage of plasma technology using mixing gas CF4/H2, a fluorination process was performed on LDPE samples in the present paper. Different exposure times and discharge voltage levels were applied to produce four different types of samples. It has been found that after fluorination, space charge injection is obviously suppressed. And with longer fluorination times and higher discharge voltage, injected homocharges are reduced. By employing x-ray photoelectron spectroscopy, new chemical groups of C-F bindings are confirmed to be introduced by fluorination process of the plasma treatment. The charge suppression effect can be explained as: surface traps introduced by fluorination will reduce the interface field at both electrodes. Moreover, for fluorinated samples, heterocharge emerges obviously under 30 kV \\text{m}{{\\text{m}}-1} , which are considered as charges ionized from degradation products of etching and/or lower weight molecular specifies. Through the conductivity measurements also performed at 30 kV \\text{m}{{\\text{m}}-1} , it is found that, for the fluorinated samples with the better charge blocking effect, the conductivity is lowered. However, the conductivity of the fluorinated sample with the lightest degree of fluorination is found to be higher than that of normal samples.

  9. Theoretical Design and Calculation of a Crown Ether Phase-Transfer-Catalyst Scaffold for Nucleophilic Fluorination Merging Two Catalytic Concepts.

    Science.gov (United States)

    Carvalho, Nathália F; Pliego, Josefredo R

    2016-09-16

    Fluorinated organic molecules are playing an increased role in the area of pharmaceuticals and agrochemicals. This fact demands the development of efficient catalytic fluorination processes. In this paper, we have designed a new crown ether with four hydroxyl groups strategically positioned. The catalytic activity of this basic scaffold was investigated with high levels of electronic structure theory, such as the ONIOM approach combining MP4 and MP2 methods. On the basis of the calculations, this new structure is able to solubilize potassium fluoride in toluene solution much more efficiently than 18-crown-6 (18C6). In addition, the strong interaction of the new catalyst with the SN2 transition state leads to a very important catalytic effect, with a predicted free energy barrier of 23.3 kcal mol(-1) for potassium fluoride plus ethyl bromide reaction model. Compared with experimental data and previous theoretical studies, this new catalyst is 10(4) times more efficient than 18C6 for nucleophilic fluorination of alkyl halides. The catalysis is predicted to be selective, leading to 97% of fluorination and only 3% of elimination. Catalytic fluorination of the aromatic ring has also been investigated, and although the catalyst is less efficient in this case, our analysis has indicated further development of this strategy can lead to more efficient catalysis.

  10. Fluorination of an Alumina Surface: Modeling Aluminum-Fluorine Reaction Mechanisms.

    Science.gov (United States)

    Padhye, Richa; Aquino, Adelia J A; Tunega, Daniel; Pantoya, Michelle L

    2017-07-19

    Density functional theory (DFT) calculations were performed to examine exothermic surface chemistry between alumina and four fluorinated, fragmented molecules representing species from decomposing fluoropolymers: F(-), HF, CH3F, and CF4. The analysis has strong implications for the reactivity of aluminum (Al) particles passivated by an alumina shell. It was hypothesized that the alumina surface structure could be transformed due to hydrogen bonding effects from the environment that promote surface reactions with fluorinated species. In this study, the alumina surface was analyzed using model clusters as isolated systems embedded in a polar environment (i.e., acetone). The conductor-like screening model (COSMO) was used to mimic environmental effects on the alumina surface. Four defect models for specific active -OH sites were investigated including two terminal hydroxyl groups and two hydroxyl bridge groups. Reactions involving terminal bonds produce more energy than bridge bonds. Also, surface exothermic reactions between terminal -OH bonds and fluorinated species produce energy in decreasing order with the following reactant species: CF4 > HF > CH3F. Additionally, experiments were performed on aluminum powders using thermal equilibrium analysis techniques that complement the calculations. Consistently, the experimental results show a linear relationship between surface exothermic reactions and the main fluorination reaction for Al powders. These results connect molecular level reaction kinetics to macroscopic measurements of surface energy and show that optimizing energy available in surface reactions linearly correlates to maximizing energy in the main reaction.

  11. Fluorine Chemical Shift Imaging by Nuclear Magnetic Resonance

    Science.gov (United States)

    Lee, Heung Kyu

    1990-01-01

    One of the difficulties encountered in ^{19}F NMR imaging of fluorinated blood substitutes is that these compounds often exhibit complex multi-peak spectra. These peaks result in chemical shift artifacts along the readout direction (mis-registration). In addition, each peak excites a different slice (mis-selection) when a slice selection gradient is applied. Another difficulty is due to its low concentration in the human body. Even after injecting a fluorinated compound into a living system up to the safest level, the concentration still does not appear to be enough to give a sufficient SNR. To solve the inherent problem of mis-selection, a simultaneous multislice method has been developed. The essence of this method is to use the two strongest peaks of the spectrum to excite different multiple slices simultaneously in a controlled fashion, with or without a slice gap. The images corresponding to the two spectral lines are then separated from in and out of phase images (Dixon method). A signed magnitude method is proposed in conjunction with the simultaneous multislice method. Corrected images are obtained from the magnitude of the measured images using the sign determined from the phase images. The method was tested in the presence of phase error, such as static magnetic field inhomogeneity. As alternatives, two deconvolution methods have been devised to eliminate the mis-registration artifacts and utilize the multiple spectral lines. The reblurring deconvolution method, an iterative deconvolution method, is utilized without serious noise amplifications. A pseudo parametric Wiener filter, a variation of the Wiener filter combined with a constrained least square filter, is also devised. Since the point spread function and 2D or 3D object data are already available in the time domain as the FID data, the computational overhead for either method is negligible. To enhance the signal to noise ratio and solve the problems of mis-registration and mis-selection

  12. Chemical vapor deposition of fluorine-doped zinc oxide

    Science.gov (United States)

    Gordon, Roy G.; Kramer, Keith; Liang, Haifan

    2000-06-06

    Fims of fluorine-doped zinc oxide are deposited from vaporized precursor compounds comprising a chelate of a dialkylzinc, such as an amine chelate, an oxygen source, and a fluorine source. The coatings are highly electrically conductive, transparent to visible light, reflective to infrared radiation, absorbing to ultraviolet light, and free of carbon impurity.

  13. Two‐Dimensional Fluorinated Graphene: Synthesis, Structures, Properties and Applications

    Science.gov (United States)

    Long, Peng; Feng, Yiyu; Li, Yu

    2016-01-01

    Fluorinated graphene, an up‐rising member of the graphene family, combines a two‐dimensional layer‐structure, a wide bandgap, and high stability and attracts significant attention because of its unique nanostructure and carbon–fluorine bonds. Here, we give an extensive review of recent progress on synthetic methods and C–F bonding; additionally, we present the optical, electrical and electronic properties of fluorinated graphene and its electrochemical/biological applications. Fluorinated graphene exhibits various types of C–F bonds (covalent, semi‐ionic, and ionic bonds), tunable F/C ratios, and different configurations controlled by synthetic methods including direct fluorination and exfoliation methods. The relationship between the types/amounts of C–F bonds and specific properties, such as opened bandgap, high thermal and chemical stability, dispersibility, semiconducting/insulating nature, magnetic, self‐lubricating and mechanical properties and thermal conductivity, is discussed comprehensively. By optimizing the C–F bonding character and F/C ratios, fluorinated graphene can be utilized for energy conversion and storage devices, bioapplications, electrochemical sensors and amphiphobicity. Based on current progress, we propose potential problems of fluorinated graphene as well as the future challenge on the synthetic methods and C‐F bonding character. This review will provide guidance for controlling C–F bonds, developing fluorine‐related effects and promoting the application of fluorinated graphene. PMID:27981018

  14. Influence of fluorine on vegetation. [Sinapsis

    Energy Technology Data Exchange (ETDEWEB)

    Gautier, A.

    1915-01-01

    Fluorine occurs in living organisms in 2 forms, always associated with P. In epidermal tissues, nails, hair, and other tissues by which it is finally eliminated, the proportion of F to P is about the same as in apatite. In cells of glands, muscles, and nerves the proportion of F to P sinks 1 to 400. In artificial media of known F content, F in most cases favored the growth, flowering and seed production of plants, especially of Sinapsis. In exceptional cases such as corn, rye and oats, its influence remains doubtful. In rare cases it was found harmful.

  15. Enhanced Bioactivity and Bacteriostasis of Surface Fluorinated Polyetheretherketone.

    Science.gov (United States)

    Chen, Meiling; Ouyang, Liping; Lu, Tao; Wang, Heying; Meng, Fanhao; Yang, Yan; Ning, Congqin; Ma, Jingzhi; Liu, Xuanyong

    2017-05-24

    Although polyetheretherketone (PEEK) has been considered as a potential orthopedic and dental application material due to its similar elastic modulus as bones, inferior osseointegration and bacteriostasis of PEEK hampers its clinical application. In this work, fluorinated PEEK was constructed via plasma immersion ion implantation (PIII) followed by hydrofluoric acid treatment to ameliorate the osseointegration and antibacterial properties of PEEK. The surface microstructure, composition, and hydrophilicity of all samples were investigated. Rat bone mesenchymal stem cells (rBMSCs) were cultured on their surfaces to estimate bioactivity. The fluorinated PEEK can enhance the cell adhesion, cell spreading, proliferation, and alkaline phosphatase (ALP) activity compared to pristine PEEK. Furthermore, the fluorinated PEEK surface exhibits good bacteriostatic effect against Porphyromonas gingivalis, which is one of the major periodontal pathogens. In summary, we provide an effective route to introduce fluorine and the results reveal that the fluorinated PEEK can enhance the osseointegration and bacteriostasis, which provides a potential candidate for dental implants.

  16. Influence of fluorination on UV spectra of polyurethane structural fragments

    Science.gov (United States)

    Ksenofontov, M. A.; Ponarjadov, V. V.; Umreiko, D. S.; Shundalau, M. B.; Bobkova, E. J.

    2013-07-01

    Results of TDDFT calculations of the characteristics for excited singlet states of fluorinated urethanes containing from one to six fluorine atoms were presented. The influence of the number and location of the fluorine atoms in the urethane structure on the formation of its UV absorption spectrum was analyzed. It was established that fluorination of a phenyl group in the ortho-positions led to steric hindrance in the urethane structure and to rotation of the urethane group by a significant angle (of about 20°). The rotation angle of the urethane group could reach 60° and more with additional fluorination of the amine. Such changes in the urethane structure were accompanied by characteristic significant bathochromic shifts of the long-wavelength absorption bands.

  17. Structure-activity relationships in tripodal transmembrane anion transporters: the effect of fluorination.

    Science.gov (United States)

    Busschaert, Nathalie; Wenzel, Marco; Light, Mark E; Iglesias-Hernández, Paulina; Pérez-Tomás, Ricardo; Gale, Philip A

    2011-09-07

    A series of easy-to-make fluorinated tripodal anion transporters containing urea and thiourea groups have been prepared and their anion transport properties studied. Vesicle anion transport assays using ion-selective electrodes show that this class of compound is capable of transporting chloride through a lipid bilayer via a variety of mechanisms, including chloride/H(+) cotransport and chloride/nitrate, chloride/bicarbonate, and to a lesser extent an unusual chloride/sulfate antiport process. Calculations indicate that increasing the degree of fluorination of the tripodal transmembrane transporters increases the lipophilicity of the transporter and this is shown to be the major contributing factor in the superior transport activity of the fluorinated compounds, with a maximum transport rate achieved for clog P = 8. The most active transporter 5 contained a urea functionality appended with a 3,5-bis(trifluoromethyl)phenyl group and was able to mediate transmembrane chloride transport at receptor to lipid ratios as low as 1:250000. Proton NMR titration and single crystal X-ray diffraction revealed the ability of the tripodal receptors to bind different anions with varying affinities in a 1:1 or 2:1 stoichiometry in solution and in the solid state. We also provide evidence that the most potent anion transporters are able to induce apoptosis in human cancer cells by using a selection of in vitro viability and fluorescence assays.

  18. Soil amendments and cultivar selection can improve rice yield in salt-influenced (tsunami-affected) paddy fields in Sri Lanka.

    Science.gov (United States)

    Reichenauer, Thomas G; Panamulla, Sunil; Subasinghe, Siripala; Wimmer, Bernhard

    2009-10-01

    The tsunami disaster in the Indian Ocean in December 2004 caused devastation of agricultural soils by salt water over wide areas. Many rice fields located close to the coast were affected by the flood of seawater. Electric conductivity (EC) of soils in tsunami-affected rice fields was found to be higher compared to unaffected fields 2 years after the tsunami. Four soil amendments (gypsum, dolomite, cinnamon ash and rice-husk-charcoal) were tested for their influence on improving the yield parameters of rice grown in a tsunami-affected and a non-affected area. Yield parameters were compared with an untreated control of the same cultivar (AT362) and with a salt resistant rice variety (AT354). The salt resistant variety had the highest grain yield. The two amendments gypsum and rice-husk-charcoal led to an increase in grain yield compared to the untreated control, whereas dolomite and cinnamon ash had no significant effect on grain yield.

  19. Synthesis and surface properties of fluorinated polyurethanes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, H.J. [Kongju National University, Kongju (Korea)

    2001-01-01

    Fluorinated polyurethane elastomers were synthesized by two step polyaddition of a perfluorinated polyether diol (trade name of Fomblin ZDOL{sup R}) and diisocyanates such as 4,4' -diphenyl methane diisocyanate (MDI) and toluene 2,4-diisocyanate (TDI). In order to control the Fomblin moiety of the soft segment in the synthesized elastomers to 10{approx}50%, polyether type polyols such as polypropylene glycol (PPG) and polytetramethylene glycol (PTMG) were mixed during the Polymerization reaction. Ethylene diamine or 1,4-butane diol was used as chain extenders. The structure and average molecular weight of the produced polyurethanes were confirmed by using FT-IR, 'H-NMR, DSC, and GPC. The surface properties were analyzed by using X-ray photoelectron spectroscopy (XPS) and contact angle meter. From the results of the surface analysis it was concluded that the fluorine groups were localized on the surface rather than the inside of the polyurethane films. (author). 10 refs., 5 tabs., 8 figs.

  20. Unexpected photoluminescence of fluorinated naphthalene diimides.

    Science.gov (United States)

    Maniam, Subashani; Cox, Rosalind P; Langford, Steven J; Bell, Toby D M

    2015-03-02

    Two new amino core-substituted naphthalene diimides (cNDIs) bearing fluorinated side chains have been synthesised. Steady-state and time-resolved fluorescence spectroscopy reveals unprecedented optical properties for the cNDIs with high quantum yields of ∼0.8 and fluorescence lifetimes of ∼13 ns in a range of solvents. These properties are apparent at the level of single molecules, where the compounds also show exceptional photostability under pulsed-laser excitation. Photon emission is remarkably consistent with very few long timescale (millisecond or longer) interruptions with molecules regularly undergoing >10(7) cycles of excitation and emission. Intermittencies owing to triplet-state formation occur on a sub-millisecond timescale with a low yield of 1-2%, indicating that the presence of the fluorine atoms does not lead to a significant triplet yield through the heavy-atom effect. These properties make the compounds excellent candidates for single-molecule labelling applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Fluorine detected 2D NMR experiments for the practical determination of size and sign of homonuclear F-F and heteronuclear C-F multiple bond J-coupling constants in multiple fluorinated compounds

    Science.gov (United States)

    Aspers, Ruud L. E. G.; Ampt, Kirsten A. M.; Dvortsak, Peter; Jaeger, Martin; Wijmenga, Sybren S.

    2013-06-01

    The use of fluorine in molecules obtained from chemical synthesis has become increasingly important within the pharmaceutical and agricultural industry. NMR characterization of these compounds is of great value with respect to their structure elucidation, their screening in metabolomics investigations and binding studies. The favorable NMR properties of the fluorine nucleus make NMR with fluorine detection of great value in this respect. A suite of NMR 2D F-F- and F-C-correlation experiments with fluorine detection was applied to the assignment of resonances, nJCF- and nJFF-couplings as well as the determination of their size and sign. The utilization of this experiment suite was exemplarily demonstrated for a highly fluorinated vinyl alkyl ether. Especially F-C HSQC and J-scaled F-C HMBC experiments allowed determining the size of the J-couplings of this compound. The relative sign of its homo- and heteronuclear couplings was achieved by different combinations of 2D NMR experiments, including non-selective and F2-selective F-C XLOC, F2-selective F-C HMQC, and F-F COSY. The F2-one/two-site selective F-C XLOC versions were found highly useful, as they led to simplifications of the common E.COSY patterns and resulted in a higher confidence level of the assignment by using selective excitation. The combination of F2-one/two-site selective F-C XLOC experiments with a F2-one-site selective F-C HMQC experiment provided the signs of all nJCF- and nJFF-couplings in the vinyl moiety of the test compound. Other combinations of experiments were found useful as well for special purposes when focusing for example on homonuclear couplings a combination of F-F COSY-10 with a F2-one-site selective F-C HMQC could be used. The E.COSY patterns in the spectra demonstrated were analyzed by use of the spin-selective displacement vectors, and in case of the XLOC also by use of the DQ- and ZQ-displacement vectors. The variety of experiments presented shall contribute to facilitate the

  2. Fluorinated proteins: from design and synthesis to structure and stability.

    Science.gov (United States)

    Marsh, E Neil G

    2014-10-21

    Fluorine is all but absent from biology; however, it has proved to be a remarkably useful element with which to modulate the activity of biological molecules and to study their mechanism of action. Our laboratory's interest in incorporating fluorine into proteins was stimulated by the unusual physicochemical properties exhibited by perfluorinated small molecules. These include extreme chemical inertness and thermal stability, properties that have made them valuable as nonstick coatings and fire retardants. Fluorocarbons also exhibit an unusual propensity to phase segregation. This phenomenon, which has been termed the "fluorous effect", has been effectively exploited in organic synthesis to purify compounds from reaction mixtures by extracting fluorocarbon-tagged molecules into fluorocarbon solvents. As biochemists, we were curious to explore whether the unusual physicochemical properties of perfluorocarbons could be engineered into proteins. To do this, we developed a synthesis of a highly fluorinated amino acid, hexafluoroleucine, and designed a model 4-helix bundle protein, α4H, in which the hydrophobic core was packed exclusively with leucine. We then investigated the effects of repacking the hydrophobic core of α4H with various combinations of leucine and hexafluoroleucine. These initial studies demonstrated that fluorination is a general and effective strategy for enhancing the stability of proteins against chemical and thermal denaturation and proteolytic degradation. We had originally envisaged that the "fluorous interactions", postulated from the self-segregating properties of fluorous solvents, might be used to mediate specific protein-protein interactions orthogonal to those of natural proteins. However, various lines of evidence indicate that no special, favorable fluorine-fluorine interactions occur in the core of the fluorinated α4 protein. This makes it unlikely that fluorinated amino acids can be used to direct protein-protein interactions. More

  3. Composite of a fluorine compound and a hydrogen storage alloy; Fusso kagobutsu/suiso kyuzo gokin fukugotai oyobi sono seizo hoho

    Energy Technology Data Exchange (ETDEWEB)

    Kiyokawa, K.; Takashima, M.; Yonezawa, S.

    1997-04-22

    This invention aims to present a composite of a fluorine compound and a hydrogen storage alloy which has water repellency and absorbs hydrogen effectively. This invention presents a composite of a fluorine compound and hydrogen storage alloy with a coating of a metal containing fine particles of a fluorine resin plated on the surface of hydrogen storage alloy particles. The plated metal is selected from a group of Ni, Cu, Co, Ni-P, Ni-W, Ni-W-P, Ni-B, Ni-W-B, Cu-Ni, Cu-P, Co-P, Co-B and Co-W. The plated coating is a porous coating to permit the diffusion of hydrogen. The composite of a fluorine compound and a hydrogen storage alloy is produced by forming of the plated coating of copper or copper-containing alloy containing fine particles of the fluorine resin on the hydrogen storage alloy with a method of electroplating in a phosphoric acid bath with dispersed fine particles of the fluorine resin. 2 figs.

  4. Fluorinated Compounds in US Fast Food Packaging | Science ...

    Science.gov (United States)

    Per- and polyfluoroalkyl substances (PFASs) are highly persistent synthetic chemicals, some of which have been associated with cancer, developmental toxicity, immunotoxicity, and other health effects. PFASs in grease-resistant food packaging can leach into food and increase dietary exposure. We collected ∼400 samples of food contact papers, paperboard containers, and beverage containers from fast food restaurants throughout the United States and measured total fluorine using particle-induced γ-ray emission (PIGE) spectroscopy. PIGE can rapidly and inexpensively measure total fluorine in solid-phase samples. We found that 46% of food contact papers and 20% of paperboard samples contained detectable fluorine (>16 nmol/cm2). Liquid chromatography/high-resolution mass spectrometry analysis of a subset of 20 samples found perfluorocarboxylates, perfluorosulfonates, and other known PFASs and/or unidentified polyfluorinated compounds (based on nontargeted analysis). The total peak area for PFASs was higher in 70% of samples (10 of 14) with a total fluorine level of >200 nmol/cm2 compared to six samples with a total fluorine level of PFAS polymers, newer replacement PFASs, or other fluorinated compounds. The prevalence of fluorinated chemicals in fast food packaging demonstrates their potentially significant contribution to dietary PFAS exposure and envi

  5. Fluorine environment in bioactive glasses: ab initio molecular dynamics simulations.

    Science.gov (United States)

    Christie, Jamieson K; Pedone, Alfonso; Menziani, Maria Cristina; Tilocca, Antonio

    2011-03-10

    Fluorinated bioactive glasses (FBGs) combine the antibacterial properties of fluorine with the biological activity of phosphosilicate glasses. Because their biomedical application depends on the release of fluorine, the detailed characterization of the fluorine environment in FBGs is the key to understand their properties. Car-Parrinello molecular dynamics (CPMD) simulations have been performed on a 45S5 Bioglass composition in which 10 mol % of the CaO has been replaced with CaF(2), and have allowed us to resolve some longstanding issues about the atomic structure of fluorinated bioglasses, with particular regard to the structural role of fluorine. F is coordinated almost entirely to the modifier ions Na and Ca, with a very small amount of residual Si-F bonds, whose fraction only becomes significant in the melt precursor. High temperature leads to Si-F bonds in both tetra- (SiO(3)F) and, less frequently, penta-coordinated (SiO(4)F and SiO(3)F(2)) complexes, showing that formation of these bonds through the expansion of the SiO(4) coordination shell is generally less favored. There is no evidence for preferential bonding of F to either modifier ion: almost all F atoms are coordinated to both calcium and sodium in a "mixed state", rather than exclusively to either, as had been conjectured. We discuss the consequences of these findings on the properties of fluorine-containing bioglasses. © 2011 American Chemical Society

  6. Exraction and separation of CERIUM(IV/FLUORINE in fluoride-bearing cerium sulfate solution with fluoride coordination agent

    Directory of Open Access Journals (Sweden)

    Y. Li

    2014-07-01

    Full Text Available In this paper the extraction and separation of cerium/fluorine in fluoride-bearing cerium sulfate solution with fluoride coordination agent has been studied. The UV-vis spectra suggest that Zr6+ and Al3+ can scrub the F- from [CeF2] 2+ complex. The separation and conductivity studies show that aluminum salt is the most suitable fluoride coordination agent, and an ion-exchange reaction is involved between Ce4+/ [CeF2] 2+ and hydrogen ion.

  7. In situ gel-to-crystal transition and synthesis of metal nanoparticles obtained by fluorination of a cyclic β-aminoalcohol gelator.

    Science.gov (United States)

    Xu, Yang; Kang, Chuanqing; Chen, Yu; Bian, Zheng; Qiu, Xuepeng; Gao, Lianxun; Meng, Qingxin

    2012-12-21

    A new fluorinated version of a cyclic β-aminoalcohol gelator derived from 1,2,3,4-tetrahydroisoquinoline is presented. The gelator is able to gel various nonprotic solvents through OH⋅⋅⋅N hydrogen bonds and additional CH⋅⋅⋅F interactions due to the introduction of fluorine. A bimolecular lamellar structure is formed in the gel phase, which partly preserves the pattern of molecular organization in the single crystal. The racemate of the chiral gelator shows lower gelation ability than its enantiomer because of a higher tendency to form microcrystals, as shown by X-ray diffraction analysis. The influence of fluorination on the self-assembly of the gelator and the properties of the gel was investigated in comparison to the original fluorine-free gel system. The introduction of fluorine brings two new features. The first is good recognition of o-xylene by the gelator, which induces an in situ transition from gels of o-xylene and of an o-xylene/toluene mixture to identical single crystals with unique tubular architecture. The second is the enhanced stability of the toluene gel towards ions, including quaternary ammonium salts, which enables the preparation of a stable toluene gel in the presence of chloroaurate or chloroplatinate. The gel system can be used as a template for the synthesis of spherical gold nanoparticles with a diameter of 5 to 9 nm and wormlike platinum nanostructures with a diameter of 2 to 3 nm and a length of 5 to 12 nm. This is the first example of a synthesis of platinum nanoparticles in an organogel medium. Therefore, the appropriate introduction of a fluorine atom and corresponding nonbonding interactions into a known gelator to tune the properties and functions of a gel is a simple and effective tactic for design of a gel system with specific targets. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Decarboxylative Fluorination of Aliphatic Carboxylic Acids via Photoredox Catalysis

    Science.gov (United States)

    Ventre, Sandrine; Petronijevic, Filip R.; MacMillan, David W. C.

    2016-01-01

    The direct conversion of aliphatic carboxylic acids to the corresponding alkyl fluorides has been achieved via visible light-promoted photoredox catalysis. This operationally simple, redox-neutral fluorination method is amenable to a wide variety of carboxylic acids. Photon-induced oxidation of carboxylates leads to the formation of carboxyl radicals, which upon rapid CO2-extrusion and F• transfer from a fluorinating reagent yield the desired fluoroalkanes with high efficiency. Experimental evidence indicates that an oxidative quenching pathway is operable in this broadly applicable fluorination protocol. PMID:25881929

  9. Fluorine-18 patents (2009-2015). Part 2: new radiochemistry.

    Science.gov (United States)

    Mossine, Andrew V; Thompson, Stephen; Brooks, Allen F; Sowa, Alexandra R; Miller, Jason M; Scott, Peter Jh

    2016-09-01

    Fluorine-18 ((18)F) is one of the most common positron-emitting radionuclides used in the synthesis of positron emission tomography radiotracers due to its ready availability, convenient half-life and outstanding imaging properties. In Part 1 of this review, we presented the first analysis of patents issued for novel radiotracers labeled with fluorine-18. In Part 2, we follow-up with a focus on patents issued for new radiochemistry methodology using fluorine-18 issued between January 2009 and December 2015.

  10. Lithium salts based on a series of new anilinyl-perfluorosulfonamide salts and their polymer electrolytes

    Science.gov (United States)

    Thiam, A.; Iojoiu, C.; Leprêtre, J.-C.; Sanchez, J.-Y.

    2017-10-01

    Polymer electrolytes based on a series of new lithium anilinyl-perfluorosulfonamide exhibit conductivities close to LiTFSI ones and higher cationic transference numbers. Taking advantage of an extended delocalization on the negative charge, the anodic stability of the salts was found to range between 4.2 and 4.9 V vs Li/Li+, according to the electron-withdrawing group EWG located in para/ortho position. The simplicity of the synthesis process of the new salts, with lower fluorine content than LiPF6 and LiTFSI, paves the way for a further semi-pilot scale-up. Moreover, Linear Free Energy Relationships, LFER, were established for the first time, for both ionic conductivity and anodic stability. These LFER demonstrate unambiguously and quantitatively the conductivity dependence on anion basicity. Polymer electrolytes were soundly investigated through a variety of physicochemical and electrochemical characterizations.

  11. Influence of Nanosegregation on the Surface Tension of Fluorinated Ionic Liquids

    Science.gov (United States)

    Luís, Andreia; Shimizu, Karina; Araújo, João M. M.; Carvalho, Pedro J.; Lopes-da-Silva, José A.; Canongia Lopes, José N.; Rebelo, Luís Paulo N.; Coutinho, João A. P.; Freire, Mara G.; Pereiro, Ana B.

    2017-01-01

    We have investigated, both theoretically and experimentally, the balance between the presence of alkyl and perfluoroalkyl side chains on the surface organization and surface tension of fluorinated ionic liquids (FILs). A series of ILs composed of 1-alkyl-3-methylimidazolium cations ([CnC1im] with n = 2, 4, 6, 8, 10 or 12) combined with the perfluorobutanesulfonate anion was used. The surface tensions of the investigated liquid salts are considerably lower than those reported for non-fluorinated ionic liquids. The most surprising and striking feature was the identification, for the first time, of a minimum at n = 8 in the surface tension versus the length of the IL cation alkyl side chain. Supported by molecular dynamic simulations it was found that this trend is a result of the competition between the two nonpolar domains (perfluorinated and aliphatic) on pointing towards the gas-liquid interface, a phenomenon which occurs in ionic liquids with perfluorinated anions. Furthermore, these ionic liquids present the lowest surface entropy reported to date. PMID:27218210

  12. Controlled Defects of Fluorine-incorporated ZnO Nanorods for Photovoltaic Enhancement.

    Science.gov (United States)

    Lee, Hock Beng; Ginting, Riski Titian; Tan, Sin Tee; Tan, Chun Hui; Alshanableh, Abdelelah; Oleiwi, Hind Fadhil; Yap, Chi Chin; Jumali, Mohd Hafizuddin Hj; Yahaya, Muhammad

    2016-09-02

    Anion passivation effect on metal-oxide nano-architecture offers a highly controllable platform for improving charge selectivity and extraction, with direct relevance to their implementation in hybrid solar cells. In current work, we demonstrated the incorporation of fluorine (F) as an anion dopant to address the defect-rich nature of ZnO nanorods (ZNR) and improve the feasibility of its role as electron acceptor. The detailed morphology evolution and defect engineering on ZNR were studied as a function of F-doping concentration (x). Specifically, the rod-shaped arrays of ZnO were transformed into taper-shaped arrays at high x. A hypsochromic shift was observed in optical energy band gap due to the Burstein-Moss effect. A substantial suppression on intrinsic defects in ZnO lattice directly epitomized the novel role of fluorine as an oxygen defect quencher. The results show that 10-FZNR/P3HT device exhibited two-fold higher power conversion efficiency than the pristine ZNR/P3HT device, primarily due to the reduced Schottky defects and charge transfer barrier. Essentially, the reported findings yielded insights on the functions of fluorine on (i) surface -OH passivation, (ii) oxygen vacancies (Vo) occupation and (iii) lattice oxygen substitution, thereby enhancing the photo-physical processes, carrier mobility and concentration of FZNR based device.

  13. Effect of plasma fluorination variables on the deposition and growth of partially fluorinated polymer over PMMA films

    Directory of Open Access Journals (Sweden)

    Giovana da Silva Padilha

    2013-01-01

    Full Text Available In this work, an investigation was made of the modification of film surface of Poly(methylmethacrylate (PMMA using the plasma polymerization technique. PMMA films 10 µm thick were obtained by Spin-Coating starting from a chloroform solution (15.36% w/w. The films were exposed to the plasma of CHF3 at different gas pressures and exposure times to increase the thickness of fluorinated polymers onto PMMA films. The plasma fluorinated optical films were characterized by gravimetry, FTIR-ATR, contact angle of wetting, SEM and AFM. The surface fluorination of PMMA films can be inferred by the increase in contact angle under all experimental conditions, and confirmed with FTIR-ATR analysis. Gravimetry showed an increase of the fluorinated polymer layer over PMMA films, being 1.55 µm thick at 0.7 torr and 40 minutes of plasma exposure. The SEM analysis showed a well-defined layer of fluorinated polymer, with fluorine being detected in the EDS analysis. The film roughness for the fluorinated polymers was around of 200 Å, quite satisfactory for a 1.55 µm cladding.

  14. Partially Fluorinated Sulfonated Poly(ether amide Fuel Cell Membranes: Influence of Chemical Structure on Membrane Properties

    Directory of Open Access Journals (Sweden)

    Chulsung Bae

    2011-01-01

    Full Text Available A series of fluorinated sulfonated poly (ether amides (SPAs were synthesized for proton exchange membrane fuel cell applications. A polycondensation reaction of 4,4’-oxydianiline, 2-sulfoterephthalic acid monosodium salt, and tetrafluorophenylene dicarboxylic acids (terephthalic and isophthalic or fluoroaliphatic dicarboxylic acids produced SPAs with sulfonation degrees of 80–90%. Controlling the feed ratio of the sulfonated and unsulfonated dicarboxylic acid monomers afforded random SPAs with ion exchange capacities between 1.7 and 2.2 meq/g and good solubility in polar aprotic solvents. Their structures were characterized using NMR and FT IR spectroscopies. Tough, flexible, and transparent films were obtained with dimethylsulfoxide using a solution casting method. Most SPA membranes with 90% sulfonation degree showed high proton conductivity (>100 mS/cm at 80 °C and 100% relative humidity. Among them, two outstanding ionomers (ODA-STA-TPA-90 and ODA-STA-IPA-90 showed proton conductivity comparable to that of Nafion 117 between 40 and 80 °C. The influence of chemical structure on the membrane properties was systematically investigated by comparing the fluorinated polymers to their hydrogenated counterparts. The results suggest that the incorporation of fluorinated moieties in the polymer backbone of the membrane reduces water absorption. High molecular weight and the resulting physical entanglement of the polymers chains played a more important role in improving stability in water, however.

  15. Selective Deletion of Sodium Salt Taste during Development Leads to Expanded Terminal Fields of Gustatory Nerves in the Adult Mouse Nucleus of the Solitary Tract

    Science.gov (United States)

    Sun, Chengsan; Hummler, Edith

    2017-01-01

    Neuronal activity plays a key role in the development of sensory circuits in the mammalian brain. In the gustatory system, experimental manipulations now exist, through genetic manipulations of specific taste transduction processes, to examine how specific taste qualities (i.e., basic tastes) impact the functional and structural development of gustatory circuits. Here, we used a mouse knock-out model in which the transduction component used to discriminate sodium salts from other taste stimuli was deleted in taste bud cells throughout development. We used this model to test the hypothesis that the lack of activity elicited by sodium salt taste impacts the terminal field organization of nerves that carry taste information from taste buds to the nucleus of the solitary tract (NST) in the medulla. The glossopharyngeal, chorda tympani, and greater superficial petrosal nerves were labeled to examine their terminal fields in adult control mice and in adult mice in which the α-subunit of the epithelial sodium channel was conditionally deleted in taste buds (αENaC knockout). The terminal fields of all three nerves in the NST were up to 2.7 times greater in αENaC knock-out mice compared with the respective field volumes in control mice. The shapes of the fields were similar between the two groups; however, the density and spread of labels were greater in αENaC knock-out mice. Overall, our results show that disruption of the afferent taste signal to sodium salts disrupts the normal age-dependent “pruning” of all terminal fields, which could lead to alterations in sensory coding and taste-related behaviors. SIGNIFICANCE STATEMENT Neural activity plays a major role in the development of sensory circuits in the mammalian brain. To date, there has been no direct test of whether taste-elicited neural activity has a role in shaping central gustatory circuits. However, recently developed genetic tools now allow an assessment of how specific taste stimuli, in this case

  16. Selective Deletion of Sodium Salt Taste during Development Leads to Expanded Terminal Fields of Gustatory Nerves in the Adult Mouse Nucleus of the Solitary Tract.

    Science.gov (United States)

    Sun, Chengsan; Hummler, Edith; Hill, David L

    2017-01-18

    Neuronal activity plays a key role in the development of sensory circuits in the mammalian brain. In the gustatory system, experimental manipulations now exist, through genetic manipulations of specific taste transduction processes, to examine how specific taste qualities (i.e., basic tastes) impact the functional and structural development of gustatory circuits. Here, we used a mouse knock-out model in which the transduction component used to discriminate sodium salts from other taste stimuli was deleted in taste bud cells throughout development. We used this model to test the hypothesis that the lack of activity elicited by sodium salt taste impacts the terminal field organization of nerves that carry taste information from taste buds to the nucleus of the solitary tract (NST) in the medulla. The glossopharyngeal, chorda tympani, and greater superficial petrosal nerves were labeled to examine their terminal fields in adult control mice and in adult mice in which the α-subunit of the epithelial sodium channel was conditionally deleted in taste buds (αENaC knockout). The terminal fields of all three nerves in the NST were up to 2.7 times greater in αENaC knock-out mice compared with the respective field volumes in control mice. The shapes of the fields were similar between the two groups; however, the density and spread of labels were greater in αENaC knock-out mice. Overall, our results show that disruption of the afferent taste signal to sodium salts disrupts the normal age-dependent "pruning" of all terminal fields, which could lead to alterations in sensory coding and taste-related behaviors. Neural activity plays a major role in the development of sensory circuits in the mammalian brain. To date, there has been no direct test of whether taste-elicited neural activity has a role in shaping central gustatory circuits. However, recently developed genetic tools now allow an assessment of how specific taste stimuli, in this case sodium salt taste, play a role

  17. Ionic properties of hydrogenated and fluorinated fullerenes

    Energy Technology Data Exchange (ETDEWEB)

    Compton, R.; Hettich, R.; Jin, Changming [Oak Ridge National Lab., TN (United States); Tuinman, A. [Tennessee Univ., Knoxville, TN (United States). Dept. of Chemistry; Dunlap, B. [Naval Research Lab., Washington, DC (United States)

    1994-05-01

    Using mass spectrometry, the ionization potentials (IP) of C{sub 60}H{sub n} for even-numbered n=2-12 were determined to be 6.75-7.5 eV, and for odd-numbered n were below 6.75 eV (for C{sub 60}, IP is 7.65 eV). Electron affinities (EA) of these species rapidly decrease with increasing n. IPs and EAs for C{sub 60}F{sub x}, on the other hand, both increase dramatically upon fluorination. A second electron can be added to gaseous C{sub 60}F{sub 48}{sup {minus}}; the resulting doubly charged anion is more stable than the singly charged anion.

  18. Elimination of photoresist linewidth slimming by fluorination

    Science.gov (United States)

    Garza, Cesar M.; Conley, Willard E.

    2004-05-01

    Typically resist performance has lagged behind exposure tools as new, shorter wavelengths are introduced in the never-ending industry quest to print smaller features. Over time, however, the performance improves until it matches or exceeds that of the resists used in the previous wavelength node; 193 nm resists have not been the exception. Their resolution and stability has improved but one issue that remains is linewidth slimming. This phenomenon consists in a reduction of resist features when they are exposed to an electron beam in an scanning electron microscope during linewidth metrology. Although this phenomenon has been well described and reasonably well understood, no solution exists to eliminate this problem. In this paper we show linewidth slimming can be significantly reduced by fluorinating the resist after the relief image has been developed, keeping the lithographic dimensions unchanged.

  19. Electronic transport properties of (fluorinated) metal phthalocyanine

    KAUST Repository

    Fadlallah, M M

    2015-12-21

    The magnetic and transport properties of the metal phthalocyanine (MPc) and F16MPc (M = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn and Ag) families of molecules in contact with S–Au wires are investigated by density functional theory within the local density approximation, including local electronic correlations on the central metal atom. The magnetic moments are found to be considerably modified under fluorination. In addition, they do not depend exclusively on the configuration of the outer electronic shell of the central metal atom (as in isolated MPc and F16MPc) but also on the interaction with the leads. Good agreement between the calculated conductance and experimental results is obtained. For M = Ag, a high spin filter efficiency and conductance is observed, giving rise to a potentially high sensitivity for chemical sensor applications.

  20. Partially fluorinated electrospun proton exchange membranes

    DEFF Research Database (Denmark)

    2016-01-01

    The present invention relates to a novel porous membrane layer, to a novel method for producing a membrane, and the membranes produced by the novel method. The present invention further relates to a fuel cell comprising the porous layer, as well as any use of the porous layer in a fuel cell...... or in a filter. The porous membrane layer comprises a plurality of randomly oriented fibers manufactured by electrospinning, wherein the fibers comprise a graft copolymer, wherein the graft copolymer comprises a backbone and at least one side chain, wherein the backbone comprises a partially fluorinated...... copolymer, and wherein at least one side chain of the graft copolymer comprises a polymerization product of a polymerizable proton donor group or a precursor thereof....

  1. Thin copolymer-cased light-emitting display made with fluorine-foped tin oxide substrates

    Directory of Open Access Journals (Sweden)

    Rudolf Lessmann

    2004-09-01

    Full Text Available Seven-segment displays are used to show numerical quantities in electronic equipment, being present in most of the low-end electronics. In this work we describe a novel organic light emitting display made with poly(1,10 decanedioxy 2 methoxy - 1,2 phenylene - 1,2 ethenylene - 3,6 dimethoxy - 1,4 phenylene - 1,2 ethenylene 3 methoxy - 1,4 - phenylene (OPPVDBC, tris(8-hydroxyquinolinealuminum salt (Alq3 and a hole injection layer (PEDOT:PSS: poly(3,4 - ethylenedioxythiophene : poly(styrenesulfonate. The general device structure is FTO/PEDOT:PSS/OPPVDBC/Ca/Al or FTO/PEDOT:PSS/OPPVDBC/Alq3/Ca/Al. The FTO (fluorine-doped tin oxide thin films are transparent (transmittance > 80 % in the visible region of the spectrum, conductive (< 15 omega/º for 200 nm thick films, and present high chemical stability.

  2. Selection of suitable reference genes for quantitative RT-PCR normalization in the halophyte Halostachys caspica under salt and drought stress

    OpenAIRE

    Suwei Zhang; Youling Zeng; Xiaoya Yi; Yufang Zhang

    2016-01-01

    The plants are always subjected to various environmental stress, because of plant sessile growth. qRT-PCR is a sensitive and reliable technology, and the normalization of target gene expression with suitable reference genes is very important for obtaining accurate data. Halostachys caspica is an extremely salt-tolerant halophyte belonging to Chenopodiaceae and a good candidate to explore the stress-physiological and molecular mechanism. To get truly the expression profiles of coding genes and...

  3. Unequivocal experimental evidence for a unified lithium salt-free Wittig reaction mechanism for all phosphonium Ylide types: reactions with β-heteroatom-substituted aldehydes are consistently selective for cis-oxaphosphetane-derived products.

    Science.gov (United States)

    Byrne, Peter A; Gilheany, Declan G

    2012-06-06

    The true course of the lithium salt-free Wittig reaction has long been a contentious issue in organic chemistry. Herein we report an experimental effect that is common to the Wittig reactions of all of the three major phosphonium ylide classes (non-stabilized, semi-stabilized, and stabilized): there is consistently increased selectivity for cis-oxaphosphetane and its derived products (Z-alkene and erythro-β-hydroxyphosphonium salt) in reactions involving aldehydes bearing heteroatom substituents in the β-position. The effect operates with both benzaldehydes and aliphatic aldehydes and is shown not to operate in the absence of the heteroatom substituent on the aldehyde. The discovery of an effect that is common to reactions of all ylide types strongly argues for the operation of a common mechanism in all Li salt-free Wittig reactions. In addition, the results are shown to be most easily explained by the [2+2] cycloaddition mechanism proposed by Vedejs and co-workers as supplemented by Aggarwal, Harvey, and co-workers, thus providing strong confirmatory evidence in support of that mechanism. Notably, a cooperative effect of ortho-substituents in the case of semi-stabilized ylides is confirmed and is accommodated by the cycloaddition mechanism. The effect is also shown to operate in reactions of triphenylphosphine-derived ylides and has previously been observed for reactions under aqueous conditions, thus for the first time providing evidence that kinetic control is in operation in both of these cases.

  4. Effect of modified atmosphere and vacuum packaging conditions on selected chemical and physico-chemical parameters of marinated and salted Atlantic mackerel (Scomber scombrus

    Directory of Open Access Journals (Sweden)

    Ivanović Jelena S.

    2016-01-01

    Full Text Available Chemical and physico-chemical parameters of marinated and salted Atlantic mackerel (Scomber Scombrus, with emphasis on the quality and safety parameters in modified atmosphere packaging (MAP and vacuum packaging (VP, were investigated. Quality assessment of mackerel stored in MAP (40% CO2+60% N2 and VP for up to 50 days at 4±1 °C was done by the monitoring of pH value, total volatile basic nitrogen (TVB-N, thiobarbituric acid (TBA and histamine. The pH value of fish meat was significantly lower in the marinated samples. The highest concentration of TVB-N was recorded in the salted mackerel stored under VP whereas the lowest TVB-N in the marinated mackerel stored under MAP conditions. The formation of TBA increased with the time of storage and was the lowest in the marinated mackerel stored in MAP. The concentration of histamine increased during storage and its level reached over 10 mg/100 g for the salted mackerel stored under VP conditions. The marinated mackerel packed in MAP had extended shelf life at 4±1 °C compared to that packaged in VP according to physico-chemical analysis.

  5. Selection of suitable reference genes for quantitative RT-PCR normalization in the halophyte Halostachys caspica under salt and drought stress

    Science.gov (United States)

    Zhang, Suwei; Zeng, Youling; Yi, Xiaoya; Zhang, Yufang

    2016-01-01

    The plants are always subjected to various environmental stress, because of plant sessile growth. qRT-PCR is a sensitive and reliable technology, and the normalization of target gene expression with suitable reference genes is very important for obtaining accurate data. Halostachys caspica is an extremely salt-tolerant halophyte belonging to Chenopodiaceae and a good candidate to explore the stress-physiological and molecular mechanism. To get truly the expression profiles of coding genes and miRNAs in H. caspica in response to salt and drought stress using qRT-PCR, suitable reference genes need to be confirmed. In this study, 10 candidate genes including ACT, UBC10, UBC13, TUB2, TUB3, EF1α, 5S rRNA, tRNA, U6 and miR1436 from H. caspica are chosen, and among them, the former nine are commonly used as internal control genes, and miR1436 with high sequence copies is no significant difference expression in high salinity-treated and untreated small RNA libraries of this species. The three softwares are used to analyze expression stability. The results showed that EF1α and TUB3 were the most stable under salt and drought stress, respectively, and UBC10 was the most constant aross all the samples with the both stressed combination. This work will benefit deep studies on abiotic tolerance in H. caspica. PMID:27527518

  6. Selection of suitable reference genes for quantitative RT-PCR normalization in the halophyte Halostachys caspica under salt and drought stress.

    Science.gov (United States)

    Zhang, Suwei; Zeng, Youling; Yi, Xiaoya; Zhang, Yufang

    2016-08-16

    The plants are always subjected to various environmental stress, because of plant sessile growth. qRT-PCR is a sensitive and reliable technology, and the normalization of target gene expression with suitable reference genes is very important for obtaining accurate data. Halostachys caspica is an extremely salt-tolerant halophyte belonging to Chenopodiaceae and a good candidate to explore the stress-physiological and molecular mechanism. To get truly the expression profiles of coding genes and miRNAs in H. caspica in response to salt and drought stress using qRT-PCR, suitable reference genes need to be confirmed. In this study, 10 candidate genes including ACT, UBC10, UBC13, TUB2, TUB3, EF1α, 5S rRNA, tRNA, U6 and miR1436 from H. caspica are chosen, and among them, the former nine are commonly used as internal control genes, and miR1436 with high sequence copies is no significant difference expression in high salinity-treated and untreated small RNA libraries of this species. The three softwares are used to analyze expression stability. The results showed that EF1α and TUB3 were the most stable under salt and drought stress, respectively, and UBC10 was the most constant aross all the samples with the both stressed combination. This work will benefit deep studies on abiotic tolerance in H. caspica.

  7. Fundamental studies of metal fluorination reactions. Third annual progress report

    Energy Technology Data Exchange (ETDEWEB)

    Rapp, R.A.; Reddy, S.N.S.; Chou, S.F.; Lee, B.S.

    1978-01-01

    Results are presented of investigations of the solubility and diffusivity of fluorine in copper. Other research is reported on the electronic conductivity of CaF/sub 2/ electrolyte and mixed electrode reactions in solid electrolyte cells. (JRD)

  8. DETERMINATION OF FLUORINE IONS PENETRATION DEGREE INTO ENAMEL BY EMPA

    OpenAIRE

    Beloica, D.; Vulovik, M.; Gržetik, I.; Golijanin, D.; Pavikevik, M.

    1984-01-01

    Exogen application of different preparations was done at completely healthy teeth of children up to 11 years. A month after application of fluorine, the relative teeth were extracted and the same were prepared by stamdard methods for investigation by electron microprobe ARL, type SEMQ. The results obtained showed that the highest degree of fluorine ions migration was stimulated by organic "fluorite" (amin fluoride). Very poor results were obtained by NaF, while the values obtained by "fluor-p...

  9. Synthesis and Reactivity of Aluminized Fluorinated Acrylic (AIFA) Nanocomposites (Postprint)

    Science.gov (United States)

    2012-06-18

    REACTIVITY OF ALUMINIZED FLUORINATED ACRYLIC (ALFA) NANOCOMPOSITES (POSTPRINT) 5a. CONTRACT NUMBER In-house 5b. GRANT NUMBER 5c. PROGRAM ELEMENT...throughout the energetic materials community due to their strong reactivity with aluminum powders . Herein, we report the synthesis of a novel...These materials, which we have termed aluminized fluorinated acrylic (AlFA) composites, have been prepared with particle contents ranging from 10% to

  10. Fluorinated Graphene Enables the Growth of Inorganic Thin Films by Chemical Bath Deposition on Otherwise Inert Substrates.

    Science.gov (United States)

    Lee, Woo-Kyung; Hernández, Sandra C; Robinson, Jeremy T; Walton, Scott G; Sheehan, Paul E

    2017-01-11

    Chemically modified graphenes (CMGs) offer a means to tune a wide variety of graphene's exceptional properties. Critically, CMGs can be transferred onto a variety of substrates, thereby imparting functionalities to those substrates that would not be obtainable through conventional functionalization. One such application of CMGs is enabling and controlling the subsequent growth of inorganic thin films. In the current study, we demonstrated that CMGs enhance the growth of inorganic films on inert surfaces with poor growth properties. Fluorinated graphene transferred onto polyethylene enabled the dense and homogeneous deposition of a cadmium sulfide (CdS) film grown via chemical bath deposition. We showed that the coverage of the CdS film can be controlled by the degree of fluorination from less than 20% to complete coverage of the film. The approach can also be applied to other technologically important materials such as ZnO. Finally, we demonstrated that electron beam-generated plasma in a SF6-containing background could pattern fluorine onto a graphene/PE sample to selectively grow CdS films on the fluorinated region. Therefore, CMG coatings can tailor the surface properties of polymers and control the growth of inorganic thin films on polymers for the development of flexible electronics.

  11. Electrochemical ion separation in molten salts

    Energy Technology Data Exchange (ETDEWEB)

    Spoerke, Erik David; Ihlefeld, Jon; Waldrip, Karen; Wheeler, Jill S.; Brown-Shaklee, Harlan James; Small, Leo J.; Wheeler, David R.

    2017-12-19

    A purification method that uses ion-selective ceramics to electrochemically filter waste products from a molten salt. The electrochemical method uses ion-conducting ceramics that are selective for the molten salt cations desired in the final purified melt, and selective against any contaminant ions. The method can be integrated into a slightly modified version of the electrochemical framework currently used in pyroprocessing of nuclear wastes.

  12. Fluorine-18 labeling and biodistribution studies on peroxisome proliferator-activated receptor-{gamma} ligands: potential positron emission tomography imaging agents

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Byung Chul [Department of Chemistry, University of Illinois, Urbana, IL 61801 (United States); Dence, Carmen S. [Division of Radiological Sciences, Washington University School of Medicine, St. Louis, MO 63110 (United States); Zhou Haibing; Parent, Ephraim E. [Department of Chemistry, University of Illinois, Urbana, IL 61801 (United States); Welch, Michael J. [Division of Radiological Sciences, Washington University School of Medicine, St. Louis, MO 63110 (United States); Katzenellenbogen, John A. [Department of Chemistry, University of Illinois, Urbana, IL 61801 (United States)], E-mail: jkatzene@uiuc.edu

    2009-02-15

    Introduction: Peroxisome proliferator-activated receptor-{gamma} (PPAR{gamma}) is an important regulator of lipid metabolism; it controls the differentiation of preadipocytes and is also found at high levels in small metastatic tumors. In this report, we describe the radiochemical synthesis and evaluation of two {sup 18}F-labeled analogs of the potent and selective PPAR{gamma} agonist farglitazar. Materials and methods: The isomeric aromatic fluorine-substituted target compounds [(2S)-(2-benzoylphenylamino)-3-(4-(2-[2-(4-[{sup 18}F]fluorophenyl) -5-methyloxazol-4-yl]ethoxy)-phenyl)propionic acid ([{sup 18}F]-1) and (2S)-[2-(4-fluorobenzoyl)phenylamino] -3-(4-[2-(5-methyl-2-phenyloxazol-4-yl)ethoxy]-phenyl)propionic acid ([{sup 18}F]-2)] were prepared in fluorine-18-labeled form, respectively, by radiofluorination of an iodonium salt precursor or by Ullmann-type condensation with 2-iodo-4'-[{sup 18}F]fluorobenzophenone after nucleophilic aromatic substitution with [{sup 18}F]fluoride ion. Each compound was obtained in high specific activity and good radiochemical yield. Results and Discussion: {sup 18}F-1 and {sup 18}F-2 have high and selective PPAR{gamma} binding affinities comparable to that of the parent molecule farglitazar, and they were found to have good metabolic stability. Tissue biodistribution studies of {sup 18}F-1 and {sup 18}F-2 were conducted, but PPAR{gamma}-mediated uptake of both agents was minimal. Conclusion: This study completes our first look at an important class of PPAR{gamma} ligands as potential positron emission tomography (PET) imaging agents for breast cancer and vascular disease. Although {sup 18}F-1 and {sup 18}F-2 have high affinities for PPAR{gamma} and good metabolic stability, their poor target-tissue distribution properties, which likely reflect their high lipophilicity combined with the low titer of PPAR{gamma} in target tissues, indicate that they have limited potential as PPAR{gamma} PET imaging agents.

  13. Experimental research on combustion fluorine retention using calcium-based sorbets during coal combustion (I)

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Qing-jie; Lin, Zhi-yan; Liu, Jian-zhong; Wu, Xian; Zhou, Jun-hu; Cen, Ke-fa [Liaoning Technical University, Fuxin (China). College of Resource and Environment Engineering

    2008-06-15

    In order to provide experimental guide to commercial use of fluorine pollution control during coal combustion, with fluorine pollution control during coal combustion in mind, this paper proposed the theory of combustion fluorine retention technology. Feasibility of fluorine retention reaction with calcium-based fluorine retention agent was analyzed through thermodynamic calculation during coal combustion. By simulating the restraining and retention effects and influential factors of calcium-based sorbets on vaporized fluoride during experimental combustion using fixed bed tube furnace, the paper systematically explored the influential law of such factors as combustion temperature, retention time, and added quantities of calcium-based sorbets on effects of fluorine retention. The research result shows that adding calcium-based fluorine retention agent in coal combustion has double effects of fluorine retention and sulfur retention, it lays an experimental foundation for commercial test of combustion fluorine retention. 7 refs., 2 figs., 4 tabs.

  14. Clinical value of fluorine-18?-methyltyrosine PET in patients with gliomas: comparison with fluorine-18 fluorodeoxyglucose PET

    OpenAIRE

    HORIGUCHI, Keishi; TOSAKA, Masahiko; Higuchi, Tetsuya; Arisaka, Yukiko; Sugawara, Kenichi; Hirato, Junko; Yokoo, Hideaki; Tsushima, Yoshito; Yoshimoto, Yuhei

    2017-01-01

    Background We investigated the relationship between metabolic activity and histological features of gliomas using fluorine-18?-methyltyrosine (18F-FAMT) positron emission tomography (PET) compared with fluorine-18 fluorodeoxyglucose (18F-FDG) PET in 38 consecutive glioma patients. The tumor to normal brain ratios (T/N ratios) were calculated, and the relationships between T/N ratio and World Health Organization tumor grade or MIB-1 labeling index were evaluated. The diagnostic values of T/N r...

  15. Structure-activity relationships of fluorinated dendrimers in DNA and siRNA delivery.

    Science.gov (United States)

    Wang, Mingming; Cheng, Yiyun

    2016-12-01

    Fluorinated dendrimers have shown great promise in gene delivery due to their high transfection efficacy and low cytotoxicity, however, the structure-activity relationships of these polymers still remain unknown. Herein, we synthesized a library of fluorinated dendrimers with different dendrimer generations and fluorination degrees and investigated their behaviors in both DNA and siRNA delivery. The results show that fluorination significantly improves the transfection efficacy of G4-G7 polyamidoamine dendrimers in DNA and siRNA delivery. Fluorination on generation 5 dendrimer yields the most efficient polymers in gene delivery, and the transfection efficacy of fluorinated dendrimers depends on fluorination degree. All the fluorinated dendrimers cause minimal toxicity on the transfected cells at their optimal transfection conditions. This study provides a general and facile strategy to prepare high efficient and low cytotoxic gene carriers based on fluorinated polymers. The structure-activity relationships of fluorinated dendrimers in gene delivery is still unknown and the behavior of fluorinated dendrimers in siRNA delivery has not yet been investigated. Herein, we synthesized a library of fluorinated PAMAM dendrimers with different dendrimer generations and fluorination degrees and investigated their behaviors in both DNA and siRNA delivery. The results clearly indicate that fluorination significantly improves the transfection efficacy of dendrimers in both DNA and siRNA delivery without causing additional toxicity. G5 PAMAM dendrimer is best scaffold to synthesize fluorinated dendrimers and the transfection efficacy of fluorinated dendrimers depends on fluorination degree. This systematic study provides a general and facile strategy to prepare high efficient and low cytotoxic gene carriers based on fluorinated polymers. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  16. Salting-out assisted extraction method coupled with hydrophilic interaction liquid chromatography for determination of selected β-blockers and their metabolites in human urine.

    Science.gov (United States)

    Magiera, Sylwia; Kolanowska, Anna; Baranowski, Jacek

    2016-06-01

    In this study, a new analytical method was developed and validated for the simultaneous analysis of β-blockers (metoprolol, propranolol, carvedilol) and their metabolites (5'-hydroxycarvedilol, O-desmethylcarvedilol, α-hydroxymetoprolol, O-desmethylmetoprolol, 5-hydroxypropranolol) in human urine. A salting-out assisted liquid-liquid extraction (SALLE) procedure was used for sample preparation. Several parameters affecting the extraction efficiency and method sensitivity including the type and volume of the extraction solvent, the type and quantity of the inorganic salt, extraction time and sample pH were investigated. Hydrophilic interaction liquid chromatography-ultraviolet detection (HILIC-UV) was used for the determination of all analytes. During method development, the effects of mobile phase components (type, pH, concentration of salt, organic modifier type and content, flow rate, column temperature) on the retention and separation of β-blockers and metabolites on the five different HILIC columns were examined. The method was linear for concentrations ranging from 0.1 to 8.0μg/mL, with determination coefficients higher than 0.993 for all analytes. The limits of quantification were in the range from 0.1 to 0.2μg/mL. Intra- and inter-day precision ranged from 0.1 to 8.9%, and accuracy was within±13% interval for all analytes. Under the optimized conditions, extraction efficiency was greater than 83.4% for determined compounds. The validated method was then applied to the measurement of β-blockers and their metabolites in human urine samples. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. Geology, selected geophysics, and hydrogeology of the White River and parts of the Great Salt Lake Desert regional groundwater flow systems, Utah and Nevada

    Science.gov (United States)

    Rowley, Peter D.; Dixon, Gary L.; Watrus , James M.; Burns, Andrews G.; Mankinen, Edward A.; McKee, Edwin H.; Pari, Keith T.; Ekren, E. Bartlett; Patrick , William G.; Comer, John B.; Inkenbrandt, Paul C.; Krahulec, K.A.; Pinnell, Michael L.

    2016-01-01

    The east-central Great Basin near the Utah-Nevada border contains two great groundwater flow systems. The first, the White River regional groundwater flow system, consists of a string of hydraulically connected hydrographic basins in Nevada spanning about 270 miles from north to south. The northernmost basin is Long Valley and the southernmost basin is the Black Mountain area, a valley bordering the Colorado River. The general regional groundwater flow direction is north to south. The second flow system, the Great Salt Lake Desert regional groundwater flow system, consists of hydrographic basins that straddle

  18. Root adaptation and ion selectivity affects the nutritional value of salt-stressed hidroponically grown baby-leaf Nasturtium officinale and Lactuca sativa

    OpenAIRE

    Fernández, Juan A.; Diana, Niñirola; Jesús, Ochoa; Francesco, Orsini; Giuseppina, Pennisi; Giorgio, Gianquinto; Catalina, Egea-gilabert

    2016-01-01

    The response of watercress (Nasturtium officinale L.) to salinity has been scarcely addressed in literature despite its growing importance in the baby-leaf market and its wide cultivation in salt-affected agricultural regions. This work evaluates the effect of salinity (2.5, 5 and 10 dS m-1) on productive and quality features of watercress compared with another crop widely cultivated for the baby-leaf sector (lettuce, Lactuca sativa). In watercress, a linear relationship (R2=0.75) was observe...

  19. Post-synthetic modification of porphyrin-encapsulating metal-organic materials by cooperative addition of inorganic salts to enhance CO 2/CH 4 selectivity

    KAUST Repository

    Zhang, ZhenJie

    2012-08-21

    Keeping MOM: Reaction of biphenyl-3,4\\',5-tricarboxylate and Cd(NO 3) 2 in the presence of meso-tetra(N-methyl-4-pyridyl) porphine tetratosylate afforded porph@MOM-11, a microporous metal-organic material (MOM) that encapsulates cationic porphyrins and solvent in alternating open channels. Porph@MOM-11 has cation and anion binding sites that facilitate cooperative addition of inorganic salts (such as M +Cl -) in a stoichiometric fashion. © 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Fluorinated hyperbranched polyurethane electrospun nanofibrous membrane: fluorine-enriching surface and superhydrophobic state with high adhesion to water.

    Science.gov (United States)

    Zheng, Fei; Deng, Hongtao; Zhao, Xinjun; Li, Xia; Yang, Can; Yang, Yunyan; Zhang, Aidong

    2014-05-01

    The fluorination of hyperbranched polyurethane (HPU) was achieved by atom transfer radical grafting polymerization (ATRgP) of dodecafluoroheptyl methacrylate that was initiated from 2-bromoisobutyryl bromide-modified end groups of HPU. The nanofibrous membrane of fluorinated HPU was prepared by electrospinning. The structure of fluorinated HPU was characterized by Fourier-transform infrared spectroscopy (FTIR) and (1)H nuclear magnetic resonance spectrum (1H NMR). The surface of nanofibrous membrane was investigated with scanning electron microscope (SEM), atomic force microscope (AFM), X-ray photoelectron spectroscopy (XPS) and water contact angle (WCA) analysis, respectively. The results suggested that compared with the reported linear fluorine-containing polyurethane materials, rather high fluorine content up to 29.14% was achieved on the surface of fluorinated HPU nanofibrous membrane. Meanwhile, a superhydrophobic surface (WCA 159.7°) with high adhesion to water was successfully fabricated via a convenient electrospinning process. The prepared material is promising for the application in microfluidic devices. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Fluorine speciation analysis using reverse phase liquid chromatography coupled off-line to continuum source molecular absorption spectrometry (CS-MAS): identification and quantification of novel fluorinated organic compounds in environmental and biological samples.

    Science.gov (United States)

    Qin, Zhiwei; McNee, David; Gleisner, Heike; Raab, Andrea; Kyeremeh, Kwaku; Jaspars, Marcel; Krupp, Eva; Deng, Hai; Feldmann, Jörg

    2012-07-17

    Driven by increasing demand for the monitoring of industrial perfluorinated compounds (PFCs), the identification of novel fluorine containing compounds (FOCs) and the tracking of organofluorine drugs and their degradation products, there is a clear need for sensitive, fluorine-specific detection of unknown FOCs. Here we report the first ever direct fluorine-specific (speciation) method; capable of individually detecting untargeted FOCs in environmental and biological samples through the application of continuum source molecular absorption spectrometry (CS-MAS) using a commercial CS-AAS. Two model FOCs (2,4,6, trifluorobenzoic acid (TFBA) and 5-fluoroindol-5-carboxylic acid (FICA)) were used, achieving fluorine-specific detection across a range of 0.1 to 300 ng/mL fluorine, corresponding to a limit of detection of 4 pg F and 5.26 nM for both compounds. Both TFBA and FICA showed a similar response to CS-MAS detection, potentially enabling the quantification of fluorine content in novel FOCs without having molecular standards available. This paper also reports the use of reverse-phase high performance liquid chromatography (RP-HPLC) coupled off-line with CS-MAS for the identification of single organofluorines in a mixture of FOCs via fraction collection. The linear range of both FOCs was determined to be from 1 to 500 ng/mL. The limits of detection of those species were just above 1 ng/mL (100 pg) and can therefore compete with targeted analytical methods such as ESI-MS. Finally, as a proof of principle the analysis of a fluoride-containing groundwater sample from Ghana demonstrated that this method can be used in the detection of novel FOCs, with identification achieved through parallel ESI-MS. Coupled HPLC-CS-MAS/ESI-MS is the first analytical methodology capable of selectively detecting and identifying novel FOCs, making possible the quantification of all fluorine containing compounds in one sample. This is the necessary analytical requirement to perform

  2. Low Temperature Fluorination of Aerosol Suspensions of Hydrocarbons Utilizing Elemental Fluorine.

    Science.gov (United States)

    1982-09-01

    injection of a solution of about two-thirds of those expected even when no fluorine is nsed. This the product mixture in CC14 was separated on a 3/s in...NMR spectra, CI and Ml mass spectra and III gime. Reaction P7/N.? yields 0.54 g of F- neopen tan for 51 hInmmol/h spectra. As is also the case for...by single GLC injection (Figure 4). Reaction PF/D-I pro- side of the ring can be determined. 3’b This information allowed the duced 0.7963 g of F-l,4

  3. Design and membrane-disruption mechanism of charge-enriched AMPs exhibiting cell selectivity, high-salt resistance, and anti-biofilm properties.

    Science.gov (United States)

    Han, Hyo Mi; Gopal, Ramamourthy; Park, Yoonkyung

    2016-02-01

    Cationic antimicrobial peptides (AMPs) are essential components of the innate immune system, offering protection against invading pathogenic bacteria. In nature, AMPs serve as antibiotics with broad-spectrum antimicrobial and anti-biofilm properties. However, low effective stability in high-salt environments and physiological instability in biological membranes limit the applicability of naturally occurring AMPs as novel therapeutics. We therefore designed short synthetic cationic peptides by substituting key residues in myxinidin, an AMP derived from the epidermal mucus of hagfish, with lysine (Lys, K), arginine (Arg, R), and tryptophan (Trp, W). The resultant myxinidin analogs exhibited strong antimicrobial activity against both Gram-positive and Gram-negative bacteria, including multidrug-resistant strains, even under high-salt conditions. Moreover, these peptides showed high binding affinity for both lipopolysaccharides and lipoteichoic acids and inhibited biofilm formation by most bacteria, but did not cause significant lysis of human red blood cells and were not cytotoxic to normal human keratinocytes. Circular dichroism analysis revealed that myxinidin and its analogs assumed α-helical or β-sheet structures within artificial liposomes and bacterial membranes. In addition, bacterial killing and membrane permeation experiments demonstrated that the myxinidin analogs permeated through bacterial membranes, leading to cytoplasmic disruption and cell death. Taken together, these findings suggest myxinidin analogs may be promising candidate antibiotic agents for therapeutic application against antibiotic-resistant bacteria.

  4. Fundamental studies of metal fluorination reactions. Annual progress report

    Energy Technology Data Exchange (ETDEWEB)

    Rapp, R.A.

    1976-01-28

    Solid-state electrochemical methods are being used to determine structural, thermodynamic, and transport properties in materials pertinent to the fluorination of metals at elevated temperatures. The solubility and diffusivity of fluorine in solid metals (initially nickel) are being studied by a potentiostatic electrochemical procedure by which changes in an impressed cell voltage induces changes in the activity of fluorine at a metal/electrolyte interface while the recording of the resulting cell current as a function of time can be interpreted to yield the desired quantities. Defect structures in metal fluoride compounds (initially NiF/sub 2/ and PbF/sub 2/) are being studied through measurements and interpretation of the electrical conductivity. The variation in the conductivities of the pure and impurity-doped compound as a function of fluorine activity can be interpreted to establish the partial ionic and electronic conductivities of the compounds, and the concentrations and mobilities of the carriers. Finally, a CaF/sub 2/-electrolyte probe (gauge) is being developed for the measurement of fluorine activities in gases at elevated temperatures. The literature has been searched and studied. Experimental materials have been ordered and two high-temperature electrochemical systems have been constructed and tested. The electrical instrumentation has been tested and calibrated. A porous graphite electrode was found to be effective in fixing and transmitting fluorine activities which are set electrochemically at one graphite/electrolyte interface. This preliminary success establishes the intended means for the variation of fluorine activity in the electrical and conductivity measurements. Coexistence electrodes of nickel plus nickel fluoride at 850-950/sup 0/C have been found to remain essentially reversible despite current passage up to significant current densities. (auth)

  5. Liquid fluorine/hydrazine rhenium thruster update

    Science.gov (United States)

    Appel, M. A.; Kaplan, R. B.; Tuffias, R. H.

    1983-01-01

    The status of a fluorine/hydrazine thruster development program is discussed. A solid rhenium metal sea-level thrust chamber was successfully fabricated and tested for a total run duration of 1075 s with 17 starts. Rhenium fabrication methods are discussed. A test program was conducted to evaluate performance and chamber cooling. Acceptable performance was reached and cooling was adequate. A flight-type injector was fabricated that achieved an average extrapolated performance value of 3608 N-s/kg (368 lbf-s/lbm). Altitude thrust chambers were fabricated. One chamber incorporates a rhenium combustor and nozzle with an area ratio of 15:1, and a columbium nozzle extension with area ratios from 15:1 to 60:1. The other chamber was fabricated completely with a carbon/carbon composite. Because of the attributes of rhenium for use in high-temperature applications, a program to provide the materials and processes technology needed to reliably fabricate and/or repair vapor-deposited rhenium parts of relatively large size and complex shape is recommended.

  6. Engineering blood: synthetic substitutes from fluorinated compounds.

    Science.gov (United States)

    Lowe, Kenneth C

    2003-06-01

    Concerns about blood safety and the logistical problems associated with conventional transfusion have fuelled the search for effective alternatives (so-called blood substitutes). Such materials include hemoglobin derivatives and those based on synthetic, highly fluorinated, inert organic compounds called perfluorochemicals (PFCs). PFCs dissolve large volumes of oxygen and other gases, are unreactive in the body, and are excreted primarily as a vapor by exhalation. Liquid PFCs are immiscible with blood and other body fluids, but can be injected safely into the bloodstream as submicron emulsions. Emulsified PFCs have been evaluated in clinical trials as temporary, intravascular tissue-oxygenating fluids. One such emulsion, a commercial perflubron-based, phospholipid-stabilized formulation, is in advanced clinical trials as an alternative to transfusing donated (allogeneic) blood during surgery. Basic and clinical studies have shown that this emulsion can adequately maintain tissue oxygenation during acute blood loss with no abnormal hemodynamic changes. The use of PFC emulsions as an efficacious, short-term transfusion alternative underpins the longer term objective of producing a totally synthetic, bioengineered blood substitute.

  7. Plasma deposited fluorinated films on porous membranes

    Energy Technology Data Exchange (ETDEWEB)

    Gancarz, Irena [Department of Polymer and Carbon Materials, Wrocław University of Technology, 50-370 Wrocław (Poland); Bryjak, Marek, E-mail: marek.bryjak@pwr.edu.pl [Department of Polymer and Carbon Materials, Wrocław University of Technology, 50-370 Wrocław (Poland); Kujawski, Jan; Wolska, Joanna [Department of Polymer and Carbon Materials, Wrocław University of Technology, 50-370 Wrocław (Poland); Kujawa, Joanna; Kujawski, Wojciech [Nicolaus Copernicus University, Faculty of Chemistry, 7 Gagarina St., 87-100 Torun (Poland)

    2015-02-01

    75 KHz plasma was used to modify track etched poly(ethylene terephthalate) membranes and deposit on them flouropolymers. Two fluorine bearing monomers were used: perflourohexane and hexafluorobenzene. The modified surfaces were analyzed by means of attenuated total reflection infra-red spectroscopy, X-ray photoelectron spectroscopy, scanning electron microscopy, atomic force microscopy and wettability. It was detected that hexaflourobenxene deposited to the larger extent than perflourohaxane did. The roughness of surfaces decreased when more fluoropolymer was deposited. The hydrophobic character of surface slightly disappeared during 20-days storage of hexaflourobenzene modified membrane. Perfluorohexane modified membrane did not change its character within 120 days after modification. It was expected that this phenomenon resulted from post-reactions of oxygen with radicals in polymer deposits. The obtained membranes could be used for membrane distillation of juices. - Highlights: • Plasma deposited hydrophobic layer of flouropolymers. • Deposition degree affects the surface properties. • Hydrohilization of surface due to reaction of oxygen with entrapped radicals. • Possibility to use modified porous membrane for water distillation and apple juice concentration.

  8. Fluorine-18 labeled tracers for PET studies in the neurosciences

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Yu-Shin; Fowler, J.S.

    1995-12-31

    This chapter focuses on fluorine-18, the positron emitter with the longest half-life, the lowest positron energy and probably, the most challenging chemistry. The incorporation of F-18 into organic compounds presents many challenges, including: the need to synthesize and purify the compound within a 2--3 hour time frame; the limited number of labeled precursor molecules; the need to work on a microscale; and the need to produce radiotracers which are chemically and radiochemically pure, sterile and pyrogen-free, and suitable for intravenous injection. The PET method and F-18 labeling of organic molecules are described followed by highlights of the applications of F-18 labeled compounds in the neurosciences and neuropharmacology. It is important to emphasize the essential and pivotal role that organic synthesis has played in the progression of the PET field over the past twenty years from one in which only a handful of institutions possessed the instrumentation and staff to carry out research to the present-day situation where there are more than 200 PET centers worldwide. During this period PET has become an important scientific tool in the neurosciences, cardiology and oncology. It is important to point out that PET is by no means a mature field. The fact that a hundreds of different F-18 labeled compounds have been developed but only a few possess the necessary selectivity and sensitivity in vivo to track a specific biochemical process illustrates this and underscores a major difficulty in radiotracer development, namely the selection of priority structures for synthesis and the complexities of the interactions between chemical compounds and living systems. New developments in rapid organic synthesis are needed in order to investigate new molecular targets and to improve the quantitative nature of PET experiments.

  9. Reference values for fluorine-18-fluorodeoxyglucose and fluorine-18-sodium fluoride uptake in human arteries

    DEFF Research Database (Denmark)

    Blomberg, Björn A; Thomassen, Anders; de Jong, Pim A

    2017-01-01

    OBJECTIVE: Reference values of fluorine-18-fluorodeoxyglucose (F-FDG) and fluorine-18-sodium fluoride (F-NaF) uptake in human arteries are unknown. The aim of this study was to determine age-specific and sex-specific reference values of arterial F-FDG and F-NaF uptake. PARTICIPANTS AND METHODS......: Uptake of F-FDG and F-NaF was determined in the ascending aorta, aortic arch, and descending thoracic aorta. In addition, F-FDG uptake was determined in the carotid arteries and F-NaF uptake was determined in the coronary arteries. Arterial F-FDG and F-NaF uptake were quantified as the blood pool...... subtracted maximum activity concentration in kBq/ml (BSF-FDGmax and BSF-NaFmax, respectively). In addition to determining reference values, we evaluated the influence of age and sex on BSF-FDGmax and BSF-NaFmax. RESULTS: Arterial F-FDG and F-NaF uptake was assessed in 89 healthy adults aged 21-75 years (mean...

  10. Root adaptation and ion selectivity affects the nutritional value of salt-stressed hydroponically grown baby-leaf Nasturtium officinale and Lactuca sativa

    Directory of Open Access Journals (Sweden)

    Juan A. Fernández

    2016-12-01

    Full Text Available The response of watercress (Nasturtium officinale L. to salinity has been scarcely addressed in literature despite its growing importance in the baby-leaf market and its wide cultivation in salt-affected agricultural regions. This work evaluates the effect of salinity (2.5, 5 and 10 dS m-1 on productive and quality features of watercress compared with another crop widely cultivated for the baby-leaf sector (lettuce, Lactuca sativa. In watercress, a linear relationship (R2=0.75 was observed between yield decrease and Cl– accumulation in leaves, whereas yield was not affected by salinity in lettuce. NaCl application increased Na+ accumulation at the expense of Ca2+ uptake in the leaf tissues of both crops, but also of K+ in watercress. Health-related features were improved by salinity (e.g. increased phenolics and reduced nitrates, especially in watercress, with limited sensorial quality evaluation effects.

  11. Synthesis and evaluation of a fluorine-18 labeled antisense oligonucleotide as a potential PET tracer for NOS mRNA expression

    NARCIS (Netherlands)

    de Vries, EFJ; Vroegh, J; Dijkstra, G; Moshage, H; Elsinga, PH; Jansen, PLM; Vaalburg, W

    Inducible NO synthase (iNOS) is overexpressed in inflammatory bowel diseases. An antisense oligonucleotide with good hybridization properties for iNOS mRNA was selected using RT-PCR. The oligonucleotide was reliably labeled with fluorine-18 using N-(4-[F-18]fluorobenzyl)-2-bromoacetamide. Cellular

  12. Metal-free reduction of the greenhouse gas sulfur hexafluoride, formation of SF5 containing ion pairs and the application in fluorinations

    KAUST Repository

    Rueping, Magnus

    2017-05-04

    A protocol for the fast and selective two-electron reduction of the potent greenhouse gas sulfur hexafluoride (SF6) by organic electron donors at ambient temperature has been developed. The reaction yields solid ion pairs consisting of donor dications and SF5-anions which can be effectively used in fluorination reactions.

  13. Icephobicity of polydimethylsiloxane-b-poly(fluorinated acrylate)

    Energy Technology Data Exchange (ETDEWEB)

    Li, Hui [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); School of Chemistry and Chemical Engineering, Shandong Key Laboratory of Fluorine Chemistry and Chemical Engineering Materials, University of Jinan, Jinan 250022 (China); Li, Xiaohui; Luo, Chenghao; Zhao, Yunhui [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China); Yuan, Xiaoyan, E-mail: yuanxy@tju.edu.cn [School of Materials Science and Engineering, Tianjin University, Tianjin 300072 (China); Tianjin Key Laboratory of Composite and Functional Materials, Tianjin 300072 (China)

    2014-12-31

    A facile process to fabricate icephobic surfaces was developed by spin-coating the polydimethylsiloxane-b-poly(fluorinated acrylate) (PDMS-b-PFA) block copolymers on the substrate. The surface microstructure and chemical composition of the block copolymer films can be adjusted by changing the PDMS content. Icephobic properties of the copolymer surface were mainly ascribed to “flexible-hard” microphase separation and the ratio of fluorine to silicon. The appropriate microphase domain size and the fluorine/silicon ratio could weaken the interaction of ice and copolymer surface and delay icing of water droplets on the copolymer surface. The copolymers containing 15 wt.% PDMS showed the most outstanding icephobicity by depressing the interaction between ice and the copolymer surface. - Highlights: • PDMS-b-PFA block copolymers with different PDMS contents were synthesized. • Surface microstructure can be adjusted by changing the content of PDMS. • The ratio of fluorine/silicon increased with the decrease of the PDMS content. • Ice adhesion and shear strength were decreased by the synergistic effect of silicon and fluorine.

  14. Application of fluorine NMR for structure identification of steroids.

    Science.gov (United States)

    Ampt, Kirsten A M; Aspers, Ruud L E G; Jaeger, Martin; Geutjes, Pepijn E T J; Honing, Maarten; Wijmenga, Sybren S

    2011-05-01

    Fluorinated steroids were examined using 1D and 2D homo- and heteronuclear (19)F NMR, such as (19)F-(1) H and (19)F-(13)C. The utilization of fluorine NMR accounted for spectral simplification and resulted in a straightforward pathway for the determination of structures including the configuration of these compounds; these steroids present an illustrative example for other types of fluorinated compounds, which are increasingly encountered in drug discovery. The potential of (19)F NMR is elaborated on in detail for two compounds containing diastereotopic fluorines with different coupling patterns. The analysis of the coupling patterns and the through-space interactions resulted in the determination of the structure and configuration. Heteronuclear correlation experiments, i.e. (19)F-(1)H HETCOR, (19)F-(13)C HMQC and HMBC, and (19)F-(1)H HOESY, were applied to determine first the relative stereochemistry and then the molecular configuration at C4 and C5 of a steroidal compound bearing a fused three-membered ring with two fluorine substituents. These examples proved (19)F NMR to be a useful addition to the extensively used (1)H and (13)C NMR within structure elucidation and configuration determination of small molecules. Copyright © 2011 John Wiley & Sons, Ltd.

  15. Reduced fouling of ultrafiltration membranes via surface fluorination

    Energy Technology Data Exchange (ETDEWEB)

    Sedath, R.H.; Yates, S.F.; Li, N.N.

    1993-03-01

    Surface fluorination can affect significantly the performance of an ultrafiltration membrane used to concentrate a food-related stream. Membranes fluorinated and tested as flat sheets exhibit higher initial fluxes, and do not foul as rapidly as untreated membranes. This improvement is linked to increased surface hydrophilicity, as shown in decreased contact angle with water. This increased hydrophilicity, in turn, is linked to the addition of fluorine and oxygen to the surface. The pilot plant study did-not show the difference in membrane flux and fouling observed in the flat sheet study. Instead, fluorinated and unfluorinated modules behaved similarly. Fouling by potato waste feed was severe and resulted in formation of an extensive gel layer within the module on the membrane surface. XPS, SEM and FTIR indicate that buildup of organic material occurred on both fluorinated and unfluorinated membranes, but SEM indicates that a fibrous mat of material was observed only on the nonfluorinated membrane. We conclude that in the pilot study, membrane fouling and gel formation were so extensive that the surface interaction effect was overwhelmed.

  16. Fluorinated Compounds in US Fast Food Packaging | Science ...

    Science.gov (United States)

    Per- and polyfluoroalkyl substances (PFASs) are highly persistent synthetic chemicals, some of which have been associated with cancer, developmental toxicity, immunotoxicity, and other health effects. PFASs in grease-resistant food packaging can leach into food and increase dietary exposure. We collected ∼400 samples of food contact papers, paperboard containers, and beverage containers from fast food restaurants throughout the United States and measured total fluorine using particle-induced γ-ray emission (PIGE) spectroscopy. PIGE can rapidly and inexpensively measure total fluorine in solid-phase samples. We found that 46% of food contact papers and 20% of paperboard samples contained detectable fluorine (>16 nmol/cm2). Liquid chromatography/high-resolution mass spectrometry analysis of a subset of 20 samples found perfluorocarboxylates, perfluorosulfonates, and other known PFASs and/or unidentified polyfluorinated compounds (based on nontargeted analysis). The total peak area for PFASs was higher in 70% of samples (10 of 14) with a total fluorine level of >200 nmol/cm2 compared to six samples with a total fluorine level of food packaging demonstrates their potentially significant contribution to dietary PFAS exposure and envi

  17. Tabby graphene: Dimensional magnetic crossover in fluorinated graphite.

    Science.gov (United States)

    Makarova, T L; Shelankov, A L; Shames, A I; Zyrianova, A A; Komlev, A A; Chekhova, G N; Pinakov, D V; Bulusheva, L G; Okotrub, A V; Lähderanta, E

    2017-11-29

    Tabby is a pattern of short irregular stripes, usually related to domestic cats. We have produced Tabby patterns on graphene by attaching fluorine atoms running as monoatomic chains in crystallographic directions. Separated by non-fluorinated sp 2 carbon ribbons, sp 3-hybridized carbon atoms bonded to zigzag fluorine chains produce sp 2-sp 3 interfaces and spin-polarized edge states localized on both sides of the chains. We have compared two kinds of fluorinated graphite samples C2F x , with x near to 1 and x substantially below 1. The magnetic susceptibility of C2F x (x < 1) shows a broad maximum and a thermally activated spin gap behaviour that can be understood in a two-leg spin ladder model with ferromagnetic legs and antiferromagnetic rungs; the spin gap constitutes about 450 K. Besides, stable room-temperature ferromagnetism is observed in C2F x (x < 1) samples: the crossover to a three-dimensional magnetic behaviour is due to the onset of interlayer interactions. Similarly prepared C2F x (x ≈ 1) samples demonstrate features of two-dimensional magnetism without signs of high-temperature magnetic ordering, but with transition to a superparamagnetic state below 40 K instead. The magnetism of the Tabby graphene is stable until 520 K, which is the temperature of the structural reconstruction of fluorinated graphite.

  18. PHYSICAL PROPERTIES OF FLUORINATED PROPANE AND BUTANE DERIVATIVES AS ALTERNATIVE REFRIGERANTS

    Science.gov (United States)

    Physical property measurements are presented for 24 fluorinated propane and butane derivatives and one fluorinated ether. These measurements include melting point, boiling point, vapor pressure below the boiling point, heat of vaporization at the boiling point, critical propertie...

  19. Efficient regio- and stereoselective access to novel fluorinated β-aminocyclohexanecarboxylates

    Directory of Open Access Journals (Sweden)

    Loránd Kiss

    2013-06-01

    Full Text Available A regio- and stereoselective method has been developed for the synthesis of novel fluorinated 2-aminocyclohexanecarboxylic acid derivatives with the fluorine attached to position 4 of the ring. The synthesis starts from either cis- or trans-β-aminocyclohex-4-enecarboxylic acids and involves regio- and stereoselective transformation of the ring C–C double bond through iodooxazine formation and hydroxylation, followed by hydroxy–fluorine or oxo–fluorine exchange.

  20. Compilation of Requirements for Safe Handling of Fluorine and Fluorine-Containing Products of Uranium Hexafluoride Conversion

    Energy Technology Data Exchange (ETDEWEB)

    Ferrada, J.J.

    2000-04-03

    Public Law (PL) 105-204 requires the U.S. Department of Energy to develop a plan for inclusion in the fiscal year 2000 budget for conversion of the Department's stockpile of depleted uranium hexafluoride (DUF{sub 6}) to a more stable form over an extended period. The conversion process into a more stable form will produce fluorine compounds (e.g., elemental fluorine or hydrofluoric acid) that need to be handled safely. This document compiles the requirements necessary to handle these materials within health and safety standards, which may apply in order to ensure protection of the environment and the safety and health of workers and the public. Fluorine is a pale-yellow gas with a pungent, irritating odor. It is the most reactive nonmetal and will react vigorously with most oxidizable substances at room temperature, frequently with ignition. Fluorine is a severe irritant of the eyes, mucous membranes, skin, and lungs. In humans, the inhalation of high concentrations causes laryngeal spasm and broncospasms, followed by the delayed onset of pulmonary edema. At sublethal levels, severe local irritation and laryngeal spasm will preclude voluntary exposure to high concentrations, unless the individual is trapped or incapacitated. A blast of fluorine gas on the shaved skin of a rabbit causes a second degree burn. Lower concentrations cause severe burns of insidious onset, resulting in ulceration, similar to the effects produced by hydrogen fluoride. Hydrofluoric acid is a colorless, fuming liquid or gas with a pungent odor. It is soluble in water with release of heat. Ingestion of an estimated 1.5 grams produced sudden death without gross pathological damage. Repeated ingestion of small amounts resulted in moderately advanced hardening of the bones. Contact of skin with anhydrous liquid produces severe burns. Inhalation of AHA or aqueous hydrofluoric acid mist or vapors can cause severe respiratory tract irritation that may be fatal. Based on the extreme chemical

  1. Fluorinated Polymers as Smart Materials for Advanced Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Vanessa F. Cardoso

    2018-02-01

    Full Text Available Fluorinated polymers constitute a unique class of materials that exhibit a combination of suitable properties for a wide range of applications, which mainly arise from their outstanding chemical resistance, thermal stability, low friction coefficients and electrical properties. Furthermore, those presenting stimuli-responsive properties have found widespread industrial and commercial applications, based on their ability to change in a controlled fashion one or more of their physicochemical properties, in response to single or multiple external stimuli such as light, temperature, electrical and magnetic fields, pH and/or biological signals. In particular, some fluorinated polymers have been intensively investigated and applied due to their piezoelectric, pyroelectric and ferroelectric properties in biomedical applications including controlled drug delivery systems, tissue engineering, microfluidic and artificial muscle actuators, among others. This review summarizes the main characteristics, microstructures and biomedical applications of electroactive fluorinated polymers.

  2. Friction Properties of Surface-Fluorinated Carbon Nanotubes

    Science.gov (United States)

    Wal, R. L. Vander; Miyoshi, K.; Street, K. W.; Tomasek, A. J.; Peng, H.; Liu, Y.; Margrave, J. L.; Khabashesku, V. N.

    2005-01-01

    Surface modification of the tubular or sphere-shaped carbon nanoparticles through chemical treatment, e.g., fluorination, is expected to significantly affect their friction properties. In this study, a direct fluorination of the graphene-built tubular (single-walled carbon nanotubes) structures has been carried out to obtain a series of fluorinated nanotubes (fluoronanotubes) with variable C(n)F (n =2-20) stoichiometries. The friction coefficients for fluoronanotubes, as well as pristine and chemically cut nanotubes, were found to reach values as low as 0.002-0.07, according to evaluation tests run in contact with sapphire in air of about 40% relative humidity on a ball-on-disk tribometer which provided an unidirectional sliding friction motion. These preliminary results demonstrate ultra-low friction properties and show a promise in applications of surface modified nanocarbons as a solid lubricant.

  3. [Assessment of Soil Fluorine Pollution in Jinhua Fluorite Ore Areas].

    Science.gov (United States)

    Ye, Qun-feng; Zhou, Xiao-ling

    2015-07-01

    The contents of. soil total fluorine (TF) and water-soluble fluorine (WF) were measured in fluorite ore areas located in Jinhua City. The single factor index, geoaccumulation index and health risk assessment were used to evaluate fluorine pollution in soil in four fluorite ore areas and one non-ore area, respectively. The results showed that the TF contents in soils were 28. 36-56 052. 39 mg.kg-1 with an arithmetic mean value of 8 325.90 mg.kg-1, a geometric mean of 1 555. 94 mg.kg-1, and a median of 812. 98 mg.kg-1. The variation coefficient of TF was 172. 07% . The soil WF contents ranged from 0. 83 to 74. 63 mg.kg-1 with an arithmetic mean value of 16. 94 mg.kg-1, a geometric mean of 10. 59 mg.kg-1, and a median of 10. 17 mg.kg-1. The variation coefficient of WF was 100. 10%. The soil TF and WF contents were far higher than the national average level of the local fluorine epidemic occurrence area. The fluoride pollution in soil was significantly affected by human factors. Soil fluorine pollution in Yangjia, Lengshuikeng and Huajie fluorite ore areas was the most serious, followed by Daren fluorite ore area, and in non-ore area there was almost no fluorine pollution. Oral ingestion of soils was the main exposure route. Sensitivity analysis of model parameters showed that children's weight exerted the largest influence over hazard quotient. Furthermore, a significant positive correlation was found among the three kinds of evaluation methods.

  4. [Adsorption Properties of Fluorine onto Fulvic Acid-Bentonite Complex].

    Science.gov (United States)

    Fang, Dun; Tian, Hua-jing; Ye, Xin; He, Ci-li; Dan, You-meng; Wei, Shi-yong

    2016-03-15

    Fulvic Acid-Bentonite (FA-BENT) complex was prepared using coprecipitation method, and basic properties of the complex and sorption properties of fluorine at different environmental conditions were studied. XRD results showed that the d₀₀₁ spacing of FA- BENT complex had no obvious change compared with the raw bentonite, although the diffraction peak intensity of smectite in FA-BENT complex reduced, and indicated that FA mainly existed as a coating on the external surface of bentonite. Some functional groups (such as C==O, −OH, etc. ) of FA were observed in FA-BENT FTIR spectra, thus suggesting ligand exchange-surface complexation between FA and bentonite. Higher initial pH values of the reaction system were in favor of the adsorption of fluorine onto FA-BENT, while the equilibrium capacity decreased with the increase of pH at initial pH ≥ 4.50. The adsorption of fluorine onto FA-BENT was also affected by ionic strength, and the main reason might be the "polarity" effect. The adsorption of fluorine onto FA-BENT followed pseudo-second-order kinetic model and was controlled by chemical process ( R² = 0.999 2). Compared with the Freundlich model, Langmuir model was apparently of a higher goodness of fit (R² > 0.994 9) for absorption of fluorine onto FA-BENT. Thermodynamic parameters indicated that the adsorption process of fluorine was an spontaneously endothermic reaction, and was an entropy-driven process (ΔH 32.57 kJ · mol⁻¹, ΔS 112.31 J · (mol · K)⁻¹, ΔG −0.65- −1.76 kJ · mol⁻¹).

  5. Fluorinated silicate glass for conventional and holographic optical elements

    Science.gov (United States)

    Glebov, Leonid

    2007-04-01

    This presentation is a survey of results of a long-term research at the laboratory of photoinduced processes at CREOL/UCF. A highly homogeneous and transparent sodium-zinc-aluminum-silicate glass doped with fluorine and bromine was developed. Glass is transparent from 220 to 2700 nm. It is a crown-type optical glass having refractive index at 587.5 nm nd=1.4959 and Abbe number νd=59.2. This glass shows low dependence of refractive index on temperature dn/dtGlass can withstand multi-kilowatt laser beams. Nonlinear refractive index is the same as for fused silica. Laser damage threshold for 8 ns is about 40 /cm2. This glass becomes a photosensitive one by doping with silver and cerium. It demonstrates refractive index decrement after exposure to UV radiation followed by thermal development and therefore is used for phase volume hologram recording. Spatial modulation of refractive index resulted from precipitation of nano-crystalline phase of sodium fluoride. The main mechanism of refractive index decrement is a photoelastic effect resulted from strong tensions generated in both crystalline and vitreous phases because of difference in their coefficients of thermal expansion. Volume Bragg gratings recorded in this glass, show extremely narrow spectral and angular selectivity and have low losses combined with high tolerance to laser radiation. These gratings possess a unique ability to produce laser beam transformations directly in angular space. This feature paves a way to creation of high power lasers with stable narrow emission spectra and diffraction limited divergence.

  6. Macroevolutionary patterns of salt tolerance in angiosperms

    Science.gov (United States)

    Bromham, Lindell

    2015-01-01

    Background Halophytes are rare, with only 0·25 % of angiosperm species able to complete their life cycle in saline conditions. This could be interpreted as evidence that salt tolerance is difficult to evolve. However, consideration of the phylogenetic distribution of halophytes paints a different picture: salt tolerance has evolved independently in many different lineages, and halophytes are widely distributed across angiosperm families. In this Viewpoint, I will consider what phylogenetic analysis of halophytes can tell us about the macroevolution of salt tolerance. Hypothesis Phylogenetic analyses of salt tolerance have shown contrasting patterns in different families. In some families, such as chenopods, salt tolerance evolved early in the lineage and has been retained in many lineages. But in other families, including grasses, there have been a surprisingly large number of independent origins of salt tolerance, most of which are relatively recent and result in only one or a few salt-tolerant species. This pattern of many recent origins implies either a high transition rate (salt tolerance is gained and lost often) or a high extinction rate (salt-tolerant lineages do not tend to persist over macroevolutionary timescales). While salt tolerance can evolve in a wide range of genetic backgrounds, some lineages are more likely to produce halophytes than others. This may be due to enabling traits that act as stepping stones to developing salt tolerance. The ability to tolerate environmental salt may increase tolerance of other stresses or vice versa. Conclusions Phylogenetic analyses suggest that enabling traits and cross-tolerances may make some lineages more likely to adapt to increasing salinization, a finding that may prove useful in assessing the probable impact of rapid environmental change on vegetation communities, and in selecting taxa to develop for use in landscape rehabilitation and agriculture. PMID:25452251

  7. Diels-Alder reactions onto fluorinated and hydrogenated graphene

    Science.gov (United States)

    Denis, Pablo A.

    2017-09-01

    We studied Diels-Alder (DA) reactions onto functionalized graphene. When fluorine, hydrogen or oxygen functional groups are present on one side of the sheet, the DA cycloadditions become significantly more exergonic when performed on the opposite side. Hydrogen is more effective than fluorine and oxygen to promote these cycloadditions. In contrast with the results obtained for perfect graphene, the functionalization with H, F or O turns the DA reactions exergonic, with ΔG°298 = -127.2 kcal/mol. The reaction barriers are expected to be considerably lowered with respect to perfect graphene because the functional groups significantly reduce the distortion energy.

  8. Spectroscopic studies of fluorination of bisdiethylaminotetrachloro-triphosphazene

    Science.gov (United States)

    Bamgboye, T. Tunde; Bamgboye, Omolara A.

    Substitution of two of the chlorine atoms in cis-bisdiethylaminotetrachlorotriphosphazene with antimony trifluoride yields the corresponding 1,3-difluoride. With potassium fluorosulphite as fluorinating agent, the cis geminal difluoride can be obtained. Further fluorination of 1,3 difluoride and cis geminal difluoride with KSO 2F and antimony trifluoride respectively affords the cis isomer 1,3,5,5-tetrafluoride. Structures are proposed on the basis of 1H and 19F NMR spectra with i.r. spectroscopy assisted by gas—liquid chromatography.

  9. Fluorinated epoxy resins with high glass transition temperatures

    Science.gov (United States)

    Griffith, James R.

    1991-01-01

    Easily processed liquid resins of low dielectric constants and high glass transition temperatures are useful for the manufacture of certain composite electronic boards. That combination of properties is difficult to acquire when dielectric constants are below 2.5, glass transition temperatures are above 200 C and processability is of conventional practicality. A recently issued patent (US 4,981,941 of 1 Jan. 1991) teaches practical materials and is the culmination of 23 years of research and effort and 15 patents owned by the Navy in the field of fluorinated resins of several classes. In addition to high fluorine content, practical utility was emphasized.

  10. The behaviour of salt and salt caverns

    NARCIS (Netherlands)

    Fokker, P.A.

    1995-01-01

    Salts are mined for both storage and extraction purposes, either via dry or solution mining techniques. For operational, environmental and geological purposes, it is important to understand and predict the in situ behaviour of salt, in particular the creep and strength characteristics. A

  11. Effect of Low Salt Diet on Insulin Resistance in Salt Sensitive versus Salt Resistant Hypertension

    OpenAIRE

    Garg, Rajesh; Sun, Bei; Williams, Jonathan

    2014-01-01

    Accumulating evidence shows an increase in insulin resistance on salt restriction. We compared the effect of low salt diet on insulin resistance in salt sensitive versus salt resistant hypertensive subjects. We also evaluated the relationship between salt sensitivity of blood pressure and salt sensitivity of insulin resistance in a multivariate regression model. Studies were conducted after one week of high salt (200 mmol/day Na) and one week of low salt (10 mmol/day Na) diet. Salt sensitivit...

  12. Salt Tolerance of Desorption Electrospray Ionization (DESI)

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Ayanna U. [Purdue University; Talaty, Nari [Purdue University; Cooks, R G [Purdue University; Van Berkel, Gary J [ORNL

    2007-01-01

    Suppression of ion intensity in the presence of high salt matrices is common in most mass spectrometry ionization techniques. Desorption electrospray ionization (DESI) is an ionization method that exhibits salt tolerance, and this is investigated. DESI analysis was performed on three different drug mixtures in the presence of 0, 0.2, 2, 5, 10, and 20% NaCl:KCl weight by volume from seven different surfaces. At physiological concentrations individual drugs in each mixture were observed with each surface. Collision-induced dissociation (CID) was used to provide additional confirmation for select compounds. Multiple stage experiments, to MS5, were performed for select compounds. Even in the absence of added salt, the benzodiazepine containing mixture yielded sodium and potassium adducts of carbamazepine which masked the ions of interest. These adducts were eliminated by adding 0.1% 7M ammonium acetate to the standard methanol:water (1:1) spray solvent. Comparison of the salt tolerance of DESI with that of electrospray ionization (ESI) demonstrated much better signal/noise characteristics for DESI in this study. The salt tolerance of DESI was also studied by performing limit of detection and dynamic range experiments. Even at a salt concentration significantly above physiological concentrations, select surfaces were effective in providing spectra that allowed the ready identification of the compounds of interest. The already high salt tolerance of DESI can be optimized further by appropriate choices of surface and spray solution.

  13. Low-salt diet

    Science.gov (United States)

    Low-sodium diet; Salt restriction ... control many functions. Too much sodium in your diet can be bad for you. For most people, ... you limit salt. Try to eat a balanced diet. Buy fresh vegetables and fruits whenever possible. They ...

  14. Ion Recognition Approach to Volume Reduction of Alkaline Tank Waste by Separation of Sodium Salts

    Energy Technology Data Exchange (ETDEWEB)

    Moyer, Bruce A.; Bonnesen, Peter V.; Custelcean, Radu; Delmau, Laetitia H.; Engle, Nancy L.; Kang, Hyun-Ah; Keever, Tamara J.; Marchand, Alan P.; Gadthula, Srinivas; Gore, Vinayak K.; Huang, Zilin; Sivappa, Rasapalli; Tirunahari, Pavan K.; Levitskaia, Tatiana G.; Lumetta, Gregg J.

    2005-09-26

    The purpose of this research involving collaboration between Oak Ridge National Laboratory (ORNL) and Pacific Northwest National Laboratory (PNNL) is to explore new approaches to the separation of sodium hydroxide, sodium nitrate, and other sodium salts from high-level alkaline tank waste. The principal potential benefit is a major reduction in disposed waste volume, obviating the building of expensive new waste tanks and reducing the costs of vitrification. Principles of ion recognition are being researched toward discovery of liquid-liquid extraction systems that selectively separate sodium hydroxide and sodium nitrate from other waste components. The successful concept of pseudo hydroxide extraction using fluorinated alcohols and phenols is being developed at ORNL and PNNL toward a greater understanding of the controlling equilibria, role of solvation, and of synergistic effects involving crown ethers. Synthesis efforts are being directed toward enhanced sodium binding by crown ethers, both neutral and proton-ionizable. Studies with real tank waste at PNNL will provide feedback toward solvent compositions that have promising properties.

  15. Selective Nitrate Binding in Competitive Hydrogen Bonding Solvents: Do Anion–π Interactions Facilitate Nitrate Selectivity?**

    Science.gov (United States)

    Watt, Michelle M.; Zakharov, Lev N.

    2013-01-01

    New tripodal urea receptors demonstrate preferential binding of anions over competitive hydrogen bonding solvents. 1H NMR titrations in 10% DMSO-d6/CDCl3 show a higher affinity for nitrate over the halides for the fluorinated receptor, which is lost when the fluorines are removed. An “anion–π” interaction between the nitrate and the π-system of the ethynyl-substituted arene is proposed as the source of this selectivity. PMID:23939999

  16. Salt resistant crop plants

    KAUST Repository

    Roy, Stuart J.

    2014-04-01

    Soil salinity is a major constraint to agriculture. To improve salinity tolerance of crops, various traits can be incorporated, including ion exclusion, osmotic tolerance and tissue tolerance. We review the roles of a range of genes involved in salt tolerance traits. Different tissues and cells are adapted for specific and often diverse function, so it is important to express the genes in specific cell-types and to pyramid a range of traits. Modern biotechnology (marker- assisted selection or genetic engineering) needs to be increasingly used to introduce the correct combination of genes into elite crop cultivars. Importantly, the effects of introduced genes need to be evaluated in the field to determine their effect on salinity tolerance and yield improvement.

  17. Salt resistant crop plants.

    Science.gov (United States)

    Roy, Stuart J; Negrão, Sónia; Tester, Mark

    2014-04-01

    Soil salinity is a major constraint to agriculture. To improve salinity tolerance of crops, various traits can be incorporated, including ion exclusion, osmotic tolerance and tissue tolerance. We review the roles of a range of genes involved in salt tolerance traits. Different tissues and cells are adapted for specific and often diverse function, so it is important to express the genes in specific cell-types and to pyramid a range of traits. Modern biotechnology (marker-assisted selection or genetic engineering) needs to be increasingly used to introduce the correct combination of genes into elite crop cultivars. Importantly, the effects of introduced genes need to be evaluated in the field to determine their effect on salinity tolerance and yield improvement. Copyright © 2013 The Authors. Published by Elsevier Ltd.. All rights reserved.

  18. Discovery of 4-tert-butyl-2,6-dimethylphenylsulfur trifluoride as a deoxofluorinating agent with high thermal stability as well as unusual resistance to aqueous hydrolysis, and its diverse fluorination capabilities including deoxofluoro-arylsulfinylation with high stereoselectivity.

    Science.gov (United States)

    Umemoto, Teruo; Singh, Rajendra P; Xu, Yong; Saito, Norimichi

    2010-12-29

    Versatile, safe, shelf-stable, and easy-to-handle fluorinating agents are strongly desired in both academic and industrial arenas, since fluorinated compounds have attracted considerable interest in many areas, such as drug discovery, due to the unique effects of fluorine atoms when incorporated into molecules. This article describes the synthesis, properties, and reactivity of many substituted and thermally stable phenylsulfur trifluorides, in particular, 4-tert-butyl-2,6-dimethylphenylsulfur trifluoride (Fluolead, 1k), as a crystalline solid having surprisingly high stability on contact with water and superior utility as a deoxofluorinating agent compared to current reagents, such as DAST and its analogues. The roles of substituents on 1k in thermal and hydrolytic stability, fluorination reactivity, and the high-yield fluorination mechanism it undergoes have been clarified. In addition to fluorinations of alcohols, aldehydes, and enolizable ketones, 1k smoothly converts non-enolizable carbonyls to CF(2) groups, and carboxylic groups to CF(3) groups, in high yields. 1k also converts C(=S) and CH(3)SC(=S)O groups to CF(2) and CF(3)O groups, respectively, in high yields. In addition, 1k effects highly stereoselective deoxofluoro-arylsulfinylation of diols and amino alcohols to give fluoroalkyl arylsulfinates and arylsulfinamides, with complete inversion of configuration at fluorine and the simultaneous, selective formation of one conformational isomer at the sulfoxide sulfur atom. Considering the unique and diverse properties, relative safety, and ease of handling of 1k in addition to its convenient synthesis, it is expected to find considerable use as a novel fluorinating agent in both academic and industrial arenas.

  19. Effect of Nitrogen Fertilizer on Combined Forms and Transformation of Fluorine in Tea Garden Soil

    OpenAIRE

    ZHANG Yong-li; LIAO Wan-you; WANG Ye-jun; SU You-jian; LUO Yi; SONG Li; SUN Li

    2015-01-01

    In order to investigate the effect of nitrogen fertilizer on combined forms and transformation of fluorine in tea garden soil, soil pot experiment was carried out. The research object was red-yellow soil in Shizipu tea plantation in the south of Anhui Province. Five treatments were N0P0K0 (CK), N0P1K1 (N0), N1P1K1 (N1), N2P1K1 (N2), N3P1K1 (N3). Water-soluble fluorine content, exchangeable fluorine content, Fe/Mn oxide-bound fluorine content, organic matter-bound fluorine content, ammonium ni...

  20. Application of Fluorine in Drug Design During 2010-2015 Years: A Mini-Review.

    Science.gov (United States)

    Wang, Bao-Cheng; Wang, Li-Jun; Jiang, Bo; Wang, Shuai-Yu; Wu, Ning; Li, Xiang-Qian; Shi, Da-Yong

    2017-01-01

    The widespread application of fluorine in drug design benefits from distinctive properties. Incorporation of fluorine can positively modulate certain pharmacokinetics properties, including lipophilicity, eletrophilicity, metabolic stability, chemical stability, et al., which were of interest to medicinal chemists. Herein, fluorinated compounds, which have been designed and evaluated for anticancer, antimicrobial, anti-inflammatory and antivirus activity, et al. during the last 6 years (2010-2015) are summarized. The emphasis is to highlight the importance of fluorinated compounds and the changes in the properties of compounds when introducing fluorine atom. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  1. Effect of Nitrogen Fertilizer on Combined Forms and Transformation of Fluorine in Tea Garden Soil

    Directory of Open Access Journals (Sweden)

    ZHANG Yong-li

    2015-10-01

    Full Text Available In order to investigate the effect of nitrogen fertilizer on combined forms and transformation of fluorine in tea garden soil, soil pot experiment was carried out. The research object was red-yellow soil in Shizipu tea plantation in the south of Anhui Province. Five treatments were N0P0K0 (CK, N0P1K1 (N0, N1P1K1 (N1, N2P1K1 (N2, N3P1K1 (N3. Water-soluble fluorine content, exchangeable fluorine content, Fe/Mn oxide-bound fluorine content, organic matter-bound fluorine content, ammonium nitrogen content and soil pH value in 0~15 cm soil layer were analyzed in 10, 20, 30, 50, 70, 90 days after fertilization. The results showed that compared with CK, in the short term (10 or 20 days after applying NPK, the content of water-soluble fluorine in 0~15 cm soil layer was decreased and the content of exchangeable fluorine, Fe/Mn oxide-bound fluorine and organic matter-bound fluorine were increased. After 20 days, the content of soil water-soluble fluorine was increased and the content of soil exchangeable fluorine, Fe/Mn oxide-bound fluorine and organic matter-bound fluorine were reduced. The effect on water-soluble fluorine and exchangeable fluorine increased with time and the application rate of nitrogen. The content of water-soluble fluorine in tea garden soil had a moderately positive correlation with the application rate of nitrogen while the content of exchangeable fluorine had a moderately or highly negative correlation with the application rate of nitrogen. The content of water-soluble fluorine had a quite highly negative correlation with the soil pH (P<0.01, but the content of exchangeable fluorine had a moderately or highly negative correlation with the soil pH (P<0.01. Therefore, nitrogen fertilizer changed the soil pH during its form transformation and thus affected the transformation and the availability of fluorine in soil.

  2. Avoidance of fluorinated greenhouse gases. Possibilities of an early exit; Fluorierte Treibhausgase vermeiden. Wege zum Ausstieg

    Energy Technology Data Exchange (ETDEWEB)

    Becken, Katja; Graaf, Daniel de; Elsner, Cornelia; Hoffmann, Gabriele; Krueger, Franziska; Martens, Kerstin; Plehn, Wolfgang; Sartorius, Rolf

    2010-11-15

    In comparison to carbon dioxide, fluorinated greenhouse gases are more harmful up to a factor of 24,000. Today the amount of fluorinated greenhouse gases of the world-wide emissions of climatic harmful gases amounts 2 % and increases to 6 % in the year 2050. The authors of the contribution under consideration report on possibilities for the avoidance of the emissions of fluorinated greenhouse gases. The characteristics and ecological effects of fluorinated gases as well as the development of the emission in Germany are presented. Subsequently, the applications of fluorinated hydrocarbons are described.

  3. [3,3]-sigmatropic rearrangements of fluorinated allyl (Thio)cyanates - a tool for the synthesis of fluorinated (Thio)ureas

    National Research Council Canada - National Science Library

    Ramb, Daniel C; Kost, Lisa; Haufe, Günter

    2014-01-01

    .... Dehydration using trifluoroacetic anhydride in the presence of triethylamine formed intermediate allylic cyanates, which immediately underwent sigmatropic rearrangement to fluorinated allyl isocyanates...

  4. [A experimental study on the effect of fluorine capture of calcium based coal briquette].

    Science.gov (United States)

    Yang, Jiaolan; Chen, Dongqing; Jin, Xin; Zhao, Bingcheng; Ying, Bo; Wang, Shuquan; Li, Shengda; Yang, Cuifu

    2009-11-01

    To study on the fluorine capture effect of calcium based coal briquette with fluorine capture additive in coal-burning fluorosis area. Add proper proportions of calcium based fluorine capture additive in high fluorine coal for making coal briquette were added, and were added the fluorine in coal cinder in order to reduce its emission. Meanwhile, to determine the composes of coal briquette were added, the percentage of fluorine in coal cinder and the concentration of fluoride, sulfur dioxide and PM10 were determinated, to evaluate the effect of fluorine capture and the level of door air pollution. After pilot-scale studying on the effect of fluorine capture in 30 households at coal-burning fluorosis area in Guiding of Guizhou Province. The average fluorine capture rate were 71.8%, and the average concentration of fluoride were 0.0052 mg/m3, which reduces by 27.8% in comparison with control group and were lower than environmental air quality standard (0.007 mg/m3); and the average concentration of SO2 were 0.67 mg/m3, which reduces 52.8% in comparison with control group and slightly higher than those of indoor air quality standard (0.5 mg/m3). The application of the coal briquette made by calcium based fluorine capture additive could reduce the pollution caused by high fluorine coal, could improve the quality of indoor air.

  5. The effect of fluorine substituents in conjugated polymers

    CERN Document Server

    Loevenich, P W

    2001-01-01

    quantum efficiency of 1.1%. Furthermore, an oligo(p-phenylene vinylene) was synthesised that contained two terminal fluorinated benzene rings and two central non-fluorinated benzene rings, all connected by vinylene bridges. This material aggregated in a 'brickwall' motif, where each molecule overlaps with two halves of molecules in the row above and below. The structure of this J aggregate is due to aryl-fluoroaryl-interactions and was demonstrated by X-ray crystal structure analysis. A new route to a well-defined block copolymer with alternating PEO-solubilising groups and fluorinated distyrylbenzene units was established. The Horner Wittig reaction was used as the polycondensation reaction. The non-fluorinated analogue of this block copolymer was prepared via the Wittig reaction. Both polymers were soluble in chloroform and free-standing films could be cast from solution. The position of the HOMO and LUMO energy levels of these two materials were determined by a combination of cyclic voltammetry, UV photoel...

  6. Fluorine-Substituted Molecular Motors with a Quaternary Stereogenic Center.

    Science.gov (United States)

    Štacko, Peter; Kistemaker, Jos C M; Feringa, Ben L

    2017-05-11

    A series of unprecedented second generation molecular motors featuring a quaternary stereogenic center substituted with a fluorine atom has been synthesized. It is demonstrated that a seemingly benign replacement of the stereogenic hydrogen for a fluorine atom, regarded as a common substituent in pharmacology, resulted in a dramatic change in the energetic profile of thermal helix inversion. The barrier for the thermal helix inversion was found to increase considerably (by 20-30 kJ mol -1 ), presumably due to destabilization of the transition state by increased steric hindrance when the fluorine atom is forced to pass over the lower half of the motor. This results in the activation barrier for the thermal helix inversion to be higher than the barrier for backward thermal E-Z isomerization, impairing the motor function. A fluorine-substituted motor capable of performing unidirectional rotation is successfully prepared when these limitations are considered in the design phase. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Fluorine Compounds and Dental Health: Applications of General Chemistry Topics

    Science.gov (United States)

    Pinto, Gabriel

    2009-01-01

    An example about the use of everyday phenomena in teaching general chemistry is given. Students have a greater appreciation of the principles of chemistry if they can see the relevance to their lives. Fluorine compounds in dental applications (as topical or as systemic use) provide an excellent context in which to review core content of general…

  8. Electrochemical cell studies on fluorinated natural graphite in ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 121; Issue 3. Electrochemical cell studies on fluorinated natural graphite in propylene carbonate electrolyte with difluoromethyl acetate (MFA) additive for low temperature lithium battery application. R Chandrasekaran M Koh Y Ozhawa H Aaoyoma T Nakajima.

  9. Fluorinated bio-acceptable polymers via an ATRP macroinitiator approach

    DEFF Research Database (Denmark)

    Hansen, Natanya Majbritt Louie; Haddletion, D.M.; Hvilsted, Søren

    2007-01-01

    -methanimine with the methacrylates MMA and PEGMA and 1,1,4,7,10,10-hexamethyltriethylene tetramine (HMTETA) with MEA. In all cases the use of the fluorinated initiator results in a lower apparent rate of propagation (k(p)(aPP)) as compared with the more conventional and nonfluorinated initiator, ethyl 2-bromoisobutyrate...

  10. Vulnerable plaque detection: The role of 18-fluorine ...

    African Journals Online (AJOL)

    Shazreen Shaharuddin

    2013-07-22

    Jul 22, 2013 ... Vulnerable plaque detection: The role of 18-fluorine fluorodeoxyglucose in identifying high risk patients. Shazreen Shaharuddin a,b. , Ahmad Zaid Fattah Azman a,b. , Katiza Haida Ali c. ,. Abdul Latif Mohamad d. , Fathinul Fikri Ahmad Saad a. , Abdul Jalil Nordin a,. * a Centre for Diagnostic Nuclear Imaging ...

  11. Heterogeneous nucleation of protein crystals on fluorinated layered silicate.

    Directory of Open Access Journals (Sweden)

    Keita Ino

    Full Text Available Here, we describe an improved system for protein crystallization based on heterogeneous nucleation using fluorinated layered silicate. In addition, we also investigated the mechanism of nucleation on the silicate surface. Crystallization of lysozyme using silicates with different chemical compositions indicated that fluorosilicates promoted nucleation whereas the silicates without fluorine did not. The use of synthesized saponites for lysozyme crystallization confirmed that the substitution of hydroxyl groups contained in the lamellae structure for fluorine atoms is responsible for the nucleation-inducing property of the nucleant. Crystallization of twelve proteins with a wide range of pI values revealed that the nucleation promoting effect of the saponites tended to increase with increased substitution rate. Furthermore, the saponite with the highest fluorine content promoted nucleation in all the test proteins regardless of their overall net charge. Adsorption experiments of proteins on the saponites confirmed that the density of adsorbed molecules increased according to the substitution rate, thereby explaining the heterogeneous nucleation on the silicate surface.

  12. Nitroimidazoles, Quinolones and Oxazolidinones as Fluorine Bearing Antitubercular Clinical Candidates

    Czech Academy of Sciences Publication Activity Database

    Patel, Rahul V.; Keum, Y.S.; Park, S.W.

    2015-01-01

    Roč. 15, č. 14 (2015), s. 1174-1186 ISSN 1389-5575 R&D Projects: GA MŠk(CZ) LO1204 Institutional support: RVO:61389030 Keywords : Antitubercular drugs * delamanid * fluorine-containing drugs Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.841, year: 2015

  13. Selective Cleavage of the Aryl Ether Bonds in Lignin for Depolymerization by Acidic Lithium Bromide Molten Salt Hydrate under Mild Conditions.

    Science.gov (United States)

    Yang, Xiaohui; Li, Ning; Lin, Xuliang; Pan, Xuejun; Zhou, Yonghong

    2016-11-09

    The present study demonstrates that the concentrated lithium bromide (LiBr) solution with acid as catalyst was able to selectively cleave the β-O-4 aryl ether bond and lead to lignin depolymerization under mild conditions (e.g., in 60% LiBr with 0.3 M HCl at 110 °C for 2 h). Four industrial lignins from different pulping and biorefining processes, including softwood kraft lignin (SKL), hardwood kraft lignin (HKL), softwood ethanol organosolv lignin (EOL), and acid corncob lignin (ACL), were treated in the LiBr solution. The molecular weight, functional group, and interunit linkages of the lignins were characterized using GPC, FTIR, and NMR. The results indicated that the β-O-4 aryl ether bonds of the lignins were selectively cleaved, and both LiBr and HCl played crucial roles in catalyzing the cleavage of the ether bonds.

  14. Ethanol-selective catalytic reduction of NO by Ag/Al2O3 catalysts: Activity and deactivation by alkali salts

    DEFF Research Database (Denmark)

    Schill, Leonhard; Putluru, Siva Sankar Reddy; Jacobsen, Casper Funk

    2012-01-01

    wt.% Ag/Al2O3 catalyst was found to be the most active and CO2 selective over a wide temperature window (300–500 ◦C). Addition of 500 ppm of H2 has a mild promotional effect on the activity while SO2 has a strong negative influence on the SCR activity. Furthermore, the Ag/Al2O3 ethanol-SCR catalyst......Ag/Al2O3 catalysts with and without potassium doping were prepared by incipient wetness impregnation and characterized by N2 physisorption, XRPD, NH3-TPD and SEM. The influence of the Ag content from 1 to 5 wt.% was investigated for the selective catalytic reduction (SCR) of NO with ethanol. The 3...

  15. Fluorine-fixing efficiency on calcium-based briquette: pilot experiment, demonstration and promotion.

    Science.gov (United States)

    Yang, Jiao-lan; Chen, Dong-qing; Li, Shu-min; Yue, Yin-ling; Jin, Xin; Zhao, Bing-cheng; Ying, Bo

    2010-02-05

    The fluorosis derived from coal burning is a very serious problem in China. By using fluorine-fixing technology during coal burning we are able to reduce the release of fluorides in coal at the source in order to reduce pollution to the surrounding environment by coal burning pollutants as well as decrease the intake and accumulating amounts of fluorine in the human body. The aim of this study was to conduct a pilot experiment on calcium-based fluorine-fixing material efficiency during coal burning to demonstrate and promote the technology based on laboratory research. A proper amount of calcium-based fluorine sorbent was added into high-fluorine coal to form briquettes so that the fluorine in high-fluorine coal can be fixed in coal slag and its release into atmosphere reduced. We determined figures on various components in briquettes and fluorine in coal slag as well as the concentrations of indoor air pollutants, including fluoride, sulfur dioxide and respirable particulate matter (RPM), and evaluated the fluorine-fixing efficiency of calcium-based fluorine sorbents and the levels of indoor air pollutants. Pilot experiments on fluorine-fixing efficiency during coal burning as well as its demonstration and promotion were carried out separately in Guiding and Longli Counties of Guizhou Province, two areas with coal burning fluorosis problems. If the calcium-based fluorine sorbent mixed coal was made into honeycomb briquettes the average fluorine-fixing ratio in the pilot experiment was 71.8%. If the burning calcium-based fluorine-fixing bitumite was made into a coalball, the average of fluorine-fixing ratio was 77.3%. The concentration of fluoride, sulfur dioxide and PM10 of indoor air were decreased significantly. There was a 10% increase in the cost of briquettes due to the addition of calcium-based fluorine sorbent. The preparation process of calcium-based fluorine-fixing briquette is simple yet highly flammable and it is applicable to regions with abundant

  16. Recent Trends in Bioorthogonal Click-Radiolabeling Reactions Using Fluorine-18

    Directory of Open Access Journals (Sweden)

    Doreen Pietzsch

    2013-07-01

    Full Text Available The increasing application of positron emission tomography (PET in nuclear medicine has stimulated the extensive development of a multitude of novel and versatile bioorthogonal conjugation techniques especially for the radiolabeling of biologically active high molecular weight compounds like peptides, proteins or antibodies. Taking into consideration that the introduction of fluorine-18 (t1/2 = 109.8 min proceeds under harsh conditions, radiolabeling of these biologically active molecules represents an outstanding challenge and is of enormous interest. Special attention has to be paid to the method of 18F-introduction. It should proceed in a regioselective manner under mild physiological conditions, in an acceptable time span, with high yields and high specific activities. For these reasons and due to the high number of functional groups found in these compounds, a specific labeling procedure has to be developed for every bioactive macromolecule. Bioorthogonal strategies including the Cu-assisted Huisgen cycloaddition and its copper-free click variant, both Staudinger Ligations or the tetrazine-click reaction have been successfully applied and represent valuable alternatives for the selective introduction of fluorine-18 to overcome the afore mentioned obstacles. This comprehensive review deals with the progress and illustrates the latest developments in the field of bioorthogonal labeling with the focus on the preparation of radiofluorinated building blocks and tracers for molecular imaging.

  17. Highly Sensitive Flexible NH3 Sensors Based on Printed Organic Transistors with Fluorinated Conjugated Polymers.

    Science.gov (United States)

    Nketia-Yawson, Benjamin; Jung, A-Ra; Noh, Yohan; Ryu, Gi-Seong; Tabi, Grace Dansoa; Lee, Kyung-Koo; Kim, BongSoo; Noh, Yong-Young

    2017-03-01

    Understanding the sensing mechanism in organic chemical sensors is essential for improving the sensing performance such as detection limit, sensitivity, and other response/recovery time, selectivity, and reversibility for real applications. Here, we report a highly sensitive printed ammonia (NH3) gas sensor based on organic thin film transistors (OTFTs) with fluorinated difluorobenzothiadiazole-dithienosilole polymer (PDFDT). These sensors detected NH3 down to 1 ppm with high sensitivity (up to 56%) using bar-coated ultrathin (NH3 interactions comprise hydrogen bonds and electrostatic interactions between the PDFDT polymer backbone and NH3 gas molecules, thus lowering the highest occupied molecular orbital levels, leading to hole trapping in the OTFT sensors. Additionally, density functional theory calculations show that gaseous NH3 molecules are captured via cooperation of fluorine atoms and dithienosilole units in PDFDT. We verified that incorporation of functional groups that interact with a specific gas molecule in a conjugated polymer is a promising strategy for producing high-performance printed OTFT gas sensors.

  18. Recent trends in bioorthogonal click-radiolabeling reactions using fluorine-18.

    Science.gov (United States)

    Pretze, Marc; Pietzsch, Doreen; Mamat, Constantin

    2013-07-22

    The increasing application of positron emission tomography (PET) in nuclear medicine has stimulated the extensive development of a multitude of novel and versatile bioorthogonal conjugation techniques especially for the radiolabeling of biologically active high molecular weight compounds like peptides, proteins or antibodies. Taking into consideration that the introduction of fluorine-18 (t(1/2) = 109.8 min) proceeds under harsh conditions, radiolabeling of these biologically active molecules represents an outstanding challenge and is of enormous interest. Special attention has to be paid to the method of 18F-introduction. It should proceed in a regioselective manner under mild physiological conditions, in an acceptable time span, with high yields and high specific activities. For these reasons and due to the high number of functional groups found in these compounds, a specific labeling procedure has to be developed for every bioactive macromolecule. Bioorthogonal strategies including the Cu-assisted Huisgen cycloaddition and its copper-free click variant, both Staudinger Ligations or the tetrazine-click reaction have been successfully applied and represent valuable alternatives for the selective introduction of fluorine-18 to overcome the afore mentioned obstacles. This comprehensive review deals with the progress and illustrates the latest developments in the field of bioorthogonal labeling with the focus on the preparation of radiofluorinated building blocks and tracers for molecular imaging.

  19. Novel Synthesis of Slightly Fluorinated Graphene Quantum Dots with Luminescent and Paramagnetic Properties through Thermal Cutting of Fluorinated Graphene

    Directory of Open Access Journals (Sweden)

    Qian Feng

    2018-01-01

    Full Text Available A novel approach has been developed to synthesize slightly fluorinated graphene quantum dots (GQDs-F through thermal cutting of highly fluorinated graphene. The fluorinated graphene with substantial structure defects is fragile and is readily attacked. The direct evaporation of abundant CFn (n = 2, 3 groups near structure defects lead to the loss of adjacent skelton C atoms, and the fluorinated graphene can be thermally cut into GQDs-F with a relatively uniform nanosize in pyrolysis at 810 K. The GQDs-F with a low F/C atomic ratio of ca. 0.03 exhibit excitation wavelength-dependent properties with multicolor photoluminescence (PL from blue to green. At the same time, F adatoms that are most likely located at the edges of GQDs-F have a high efficiency of introducing paramagnetic centres, and GQDs-F show a strong paramagnetism because of sp3-type defects and magnetic zigzag edges. The graphene quantum dots with such multimodal capabilities should have great applied value in material science.

  20. Novel Synthesis of Slightly Fluorinated Graphene Quantum Dots with Luminescent and Paramagnetic Properties through Thermal Cutting of Fluorinated Graphene.

    Science.gov (United States)

    Feng, Qian; Xiao, Wenqing; Liu, Yuan; Zheng, Yongping; Lin, Yuda; Li, Jiaxin; Ye, Qingying; Huang, Zhigao

    2018-01-08

    A novel approach has been developed to synthesize slightly fluorinated graphene quantum dots (GQDs-F) through thermal cutting of highly fluorinated graphene. The fluorinated graphene with substantial structure defects is fragile and is readily attacked. The direct evaporation of abundant CFn (n = 2, 3) groups near structure defects lead to the loss of adjacent skelton C atoms, and the fluorinated graphene can be thermally cut into GQDs-F with a relatively uniform nanosize in pyrolysis at 810 K. The GQDs-F with a low F/C atomic ratio of ca. 0.03 exhibit excitation wavelength-dependent properties with multicolor photoluminescence (PL) from blue to green. At the same time, F adatoms that are most likely located at the edges of GQDs-F have a high efficiency of introducing paramagnetic centres, and GQDs-F show a strong paramagnetism because of sp³-type defects and magnetic zigzag edges. The graphene quantum dots with such multimodal capabilities should have great applied value in material science.

  1. Interactions of Fluorinated Surfactants with Diphtheria Toxin T-Domain: Testing New Media for Studies of Membrane Proteins

    Science.gov (United States)

    Rodnin, Mykola V.; Posokhov, Yevgen O.; Contino-Pépin, Christiane; Brettmann, Joshua; Kyrychenko, Alexander; Palchevskyy, Sergiy S.; Pucci, Bernard; Ladokhin, Alexey S.

    2008-01-01

    The principal difficulty in experimental exploration of the folding and stability of membrane proteins (MPs) is their aggregation outside of the native environment of the lipid bilayer. To circumvent this problem, we recently applied fluorinated nondetergent surfactants that act as chemical chaperones. The ideal chaperone surfactant would 1), maintain the MP in solution; 2), minimally perturb the MP's structure; 3), dissociate from the MP during membrane insertion; and 4), not partition into the lipid bilayer. Here, we compare how surfactants with hemifluorinated (HFTAC) and completely fluorinated (FTAC) hydrophobic chains of different length compare to this ideal. Using fluorescence correlation spectroscopy of dye-labeled FTAC and HFTAC, we demonstrate that neither type of surfactant will bind lipid vesicles. Thus, unlike detergents, fluorinated surfactants do not compromise vesicle integrity even at concentrations far in excess of their critical micelle concentration. We examined the interaction of surfactants with a model MP, DTT, using a variety of spectroscopic techniques. Site-selective labeling of DTT with fluorescent dyes indicates that the surfactants do not interact with DTT uniformly, instead concentrating in the most hydrophobic patches. Circular dichroism measurements suggest that the presence of surfactants does not alter the structure of DTT. However, the cooperativity of the thermal unfolding transition is reduced by the presence of surfactants, especially above the critical micelle concentration (a feature of regular detergents, too). The linear dependence of DTT's enthalpy of unfolding on the surfactant concentration is encouraging for future application of (H)FTACs to determine the stability of the membrane-competent conformations of other MPs. The observed reduction in the efficiency of Förster resonance energy transfer between donor-labeled (H)FTACs and acceptor-labeled DTT upon addition of lipid vesicles indicates that the protein sheds the

  2. Cationic fluorinated polymer binders for microbial fuel cell cathodes

    KAUST Repository

    Chen, Guang

    2012-01-01

    Fluorinated quaternary ammonium-containing polymers were used as catalyst binders in microbial fuel cell (MFC) cathodes. The performance of the cathodes was examined and compared to NAFION ® and other sulfonated aromatic cathode catalyst binders using linear sweep voltammetry (LSV), impedance spectroscopy, and performance tests in single chamber air-cathode MFCs. The cathodes with quaternary ammonium functionalized fluorinated poly(arylene ether) (Q-FPAE) binders showed similar current density and charge transfer resistance (R ct) to cathodes with NAFION ® binders. Cathodes containing either of these fluorinated binders exhibited better electrochemical responses than cathodes with sulfonated or quaternary ammonium-functionalized RADEL ® poly(sulfone) (S-Radel or Q-Radel) binders. After 19 cycles (19 d), the power densities of all the MFCs declined compared to the initial cycles due to biofouling at the cathode. MFC cathodes with fluorinated polymer binders (1445 mW m -2, Q-FPAE-1.4-H; 1397 mW m -2, Q-FPAE-1.4-Cl; 1277 mW m -2, NAFION ®; and 1256 mW m -2, Q-FPAE-1.0-Cl) had better performance than those with non-fluorinated polymer binders (880 mW m -2, S-Radel; 670 mW m -2, Q-Radel). There was a 15% increase in the power density using the Q-FPAE binder with a 40% higher ion exchange capacity (Q-FPAE-1.4-H compared to Q-FPAE-1.0-Cl) after 19 cycles of operation, but there was no effect on the power production due to counter ions in the binder (Cl -vs. HCO 3 -). The highest-performance cathodes (NAFION ® and Q-FPAE binders) had the lowest charge transfer resistances (R ct) in fresh and in fouled cathodes despite the presence of thick biofilms on the surface of the electrodes. These results show that fluorinated binders may decrease the penetration of the biofilm and associated biopolymers into the cathode structure, which helps to combat MFC performance loss over time. © 2012 The Royal Society of Chemistry.

  3. Submarine Salt Karst Terrains

    Directory of Open Access Journals (Sweden)

    Nico Augustin

    2016-06-01

    Full Text Available Karst terrains that develop in bodies of rock salt (taken as mainly of halite, NaCl are special not only for developing in one of the most soluble of all rocks, but also for developing in one of the weakest rocks. Salt is so weak that many surface-piercing salt diapirs extrude slow fountains of salt that that gravity spread downslope over deserts on land and over sea floors. Salt fountains in the deserts of Iran are usually so dry that they flow at only a few cm/yr but the few rain storms a decade so soak and weaken them that they surge at dm/day for a few days. We illustrate the only case where the rates at which different parts of one of the many tens of subaerial salt karst terrains in Iran flows downslope constrains the rates at which its subaerial salt karst terrains form. Normal seawater is only 10% saturated in NaCl. It should therefore be sufficiently aggressive to erode karst terrains into exposures of salt on the thousands of known submarine salt extrusions that have flowed or are still flowing over the floors of hundreds of submarine basins worldwide. However, we know of no attempt to constrain the processes that form submarine salt karst terrains on any of these of submarine salt extrusions. As on land, many potential submarine karst terrains are cloaked by clastic and pelagic sediments that are often hundreds of m thick. Nevertheless, detailed geophysical and bathymetric surveys have already mapped likely submarine salt karst terrains in at least the Gulf of Mexico, and the Red Sea. New images of these two areas are offered as clear evidence of submarine salt dissolution due to sinking or rising aggressive fluids. We suggest that repeated 3D surveys of distinctive features (± fixed seismic reflectors of such terrains could measure any downslope salt flow and thus offer an exceptional opportunity to constrain the rates at which submarine salt karst terrains develop. Such rates are of interest to all salt tectonicians and the many

  4. Catalysts for selective hydrogenation of furfural derived from the double complex salt [Pd(NH 3 ) 4 ](ReO 4 ) 2 on γ-Al 2 O 3

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Simon T.; Lamb, H. Henry

    2017-06-01

    The double complex salt [Pd(NH3)4](ReO4)2 was employed as precursor of supported bimetallic catalysts for selective hydrogenation of furfural. Direct reduction of [Pd(NH3)4](ReO4)2 on γ-Al2O3 in flowing H2 at 400 °C yields bimetallic nanoparticles 1–2 nm in size that exhibit significant interaction between the metals, as evidenced by temperature-programmed hydride decomposition (complete suppression of β-PdHx formation), extended X-ray absorption fine structure spectroscopy at the Pd K and Re LIII edges (PdRe distance = 2.72 Å), and scanning transmission electron microscopy with energy dispersive X-ray analysis. In contrast, calcination of [Pd(NH3)4](ReO4)2 on γ-Al2O3 at 350 °C in air and subsequent reduction in H2 at 400 °C results in metal segregation and formation of large (>50 nm) supported Pd particles; Re species cover the Pd particles and γ-Al2O3 support. A PdRe 1:2 catalyst prepared by sequential impregnation and calcination using HReO4 and [Pd(NH3)4](NO3)2 has a similar morphology. The catalyst derived by direct reduction of [Pd(NH3)4](ReO4)2 on γ-Al2O3 exhibits remarkably high activity for selective hydrogenation of furfural to furfuryl alcohol (FAL) at 150 °C and 1 atm. Suppression of H2 chemisorption via elimination of Pd threefold sites, as evidenced by CO diffuse-reflectance infrared Fourier transform spectroscopy, correlates with increased FAL selectivity.

  5. A fine-tuned fluorinated MOF addresses the needs for trace CO2 removal and air capture using physisorption.

    KAUST Repository

    Bhatt, Prashant

    2016-07-08

    The development of functional solid-state materials for carbon capture at low carbon dioxide (CO2) concentrations, from con-fined spaces (<0.5 %) and particularly from air (400 ppm), is of prime importance with respect to energy and environment sustainability. Herein, we report the deliberate construction of a hydrolytically stable fluorinated metal-organic framework (MOF), NbOFFIVE-1-Ni, with the proper pore system (size, shape and functionality), ideal for efficient and effective traces carbon dioxide removal. Markedly, the CO2-selective NbOFFIVE-1-Ni exhibits the highest CO2 gravimetric and volumetric uptake (ca. 1.3 mmol/g and 51.4 cm3.cm-3) for physical adsorbents at 400 ppm CO2 and 298 K. Practically, the NbOFFIVE-1-Ni affords the complete CO2 desorption at 328 K under vacuum with an associated moderate energy input of 54 kJ/mol, typical for the full CO2 desorption in reference physical adsorbents but considerably lower than the conventional chemical sorbents. Noticeably, the contracted square-like channels, affording the close proximity of the fluorine centers, permitted the enhancement of the CO2-framework interactions and subsequently the attainment of an unprecedented CO2-selectivity at very low CO2 concentrations. The precise localization of the adsorbed CO2 at the vicinity of the periodically aligned fluorine centers, promoting the selective adsorption of CO2, is evidenced by the single-crystal X-ray diffraction study on the NbOFFIVE-1-Ni hosting CO2 molecules. Cyclic CO2/N2 mixed-gas column breakthrough experiments under dry and humid conditions corroborate the excellent CO2-selectivity under practical carbon capture conditions. Pertinently, the no-table hydrolytic stability positions the NbOFFIVE-1-Ni as the new benchmark adsorbent for direct air capture and CO2 removal from confined spaces.

  6. [3,3]-sigmatropic rearrangements of fluorinated allyl (Thio)cyanates - a tool for the synthesis of fluorinated (Thio)ureas.

    Science.gov (United States)

    Ramb, Daniel C; Kost, Lisa; Haufe, Günter

    2014-01-01

    The first (thio)cyanate to iso(thio)cyanate rearrangements based on 2-fluoroallylic alcohols are presented. Long-chain 2-fluoroallylic alcohols were converted to corresponding N-unsubstituted carbamates by treatment with trichloroacetyl isocyanate. Dehydration using trifluoroacetic anhydride in the presence of triethylamine formed intermediate allylic cyanates, which immediately underwent sigmatropic rearrangement to fluorinated allyl isocyanates. Without isolation the latter delivered fluorinated ureas by addition of amines. The thiocyanate to isothiocyanate rearrangements started from the same fluorinated allylic alcohols, which were first converted to mesylates. Heating in THF with potassium thiocyanate led to fluorinated allyl isothiocyanates, via [3,3]-sigmatropic rearrangement of intermediate allyl thiocyanates. The formed products were further reacted with amines to fluorinated thioureas.

  7. Fluorine and sulfur simultaneously co-doped suspended graphene

    Science.gov (United States)

    Struzzi, C.; Sezen, H.; Amati, M.; Gregoratti, L.; Reckinger, N.; Colomer, J.-F.; Snyders, R.; Bittencourt, C.; Scardamaglia, M.

    2017-11-01

    Suspended graphene flakes are exposed simultaneously to fluorine and sulfur ions produced by the μ-wave plasma discharge of the SF6 precursor gas. The microscopic and spectroscopic analyses, performed by Raman spectroscopy, scanning electron microscopy and photoelectron spectromicroscopy, show the homogeneity in functionalization yield over the graphene flakes with F and S atoms covalently bonded to the carbon lattice. This promising surface shows potential for several applications ranging from biomolecule immobilization to lithium battery and hydrogen storage devices. The present co-doping process is an optimal strategy to engineer the graphene surface with a concurrent hydrophobic character, thanks to the fluorine atoms, and a high affinity with metal nanoparticles due to the presence of sulfur atoms.

  8. Hydrocarbon and partially fluorinated sulfonated copolymer blends as functional membranes for proton exchange membrane fuel cells

    Science.gov (United States)

    Arnett, Natalie Y.; Harrison, William L.; Badami, Anand S.; Roy, Abhishek; Lane, Ozma; Cromer, Frank; Dong, Limin; McGrath, James E.

    Polymer blending is recognized as a valuable technique used to modify and improve the mechanical, thermal, and surface properties of two different polymers or copolymers. This paper investigated the solution properties and membrane properties of a biphenol-based disulfonated poly (arylene ether sulfone) random copolymer (BPS-35) with hexafluoroisopropylidene bisphenol based sulfonated poly (arylene ether sulfone) copolymers (6FSH) and an unsulfonated biphenol-based poly (arylene ether sulfone)s. The development of blended membranes with desirable surface characteristics, reduced water swelling and similar proton conductivity is presented. Polymer blends were prepared both in the sodium salt and acid forms from dimethylacetamide (DMAc). Water uptake, specific conductivity, thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and contact angles were used to characterize the blended films. Surface enrichment of the fluorinated component is illustrated by an significant increase in the water-surface contact angle was observed when 10 wt.% 6FBPA-00 (106°) was added to BPS 35 (80°). Water weight gain was reduced by a factor of 2.

  9. Fluorine-donating electrolytes enable highly reversible 5-V-class Li metal batteries.

    Science.gov (United States)

    Suo, Liumin; Xue, Weijiang; Gobet, Mallory; Greenbaum, Steve G; Wang, Chao; Chen, Yuming; Yang, Wanlu; Li, Yangxing; Li, Ju

    2018-01-19

    Lithium metal has gravimetric capacity ∼10× that of graphite which incentivizes rechargeable Li metal batteries (RLMB) development. A key factor that limits practical use of RLMB is morphological instability of Li metal anode upon electrodeposition, reflected by the uncontrolled area growth of solid-electrolyte interphase that traps cyclable Li, quantified by the Coulombic inefficiency (CI). Here we show that CI decreases approximately exponentially with increasing donatable fluorine concentration of the electrolyte. By using up to 7 m of Li bis(fluorosulfonyl)imide in fluoroethylene carbonate, where both the solvent and the salt donate F, we can significantly suppress anode porosity and improve the Coulombic efficiency to 99.64%. The electrolyte demonstrates excellent compatibility with 5-V LiNi0.5Mn1.5O4 cathode and Al current collector beyond 5 V. As a result, an RLMB full cell with only 1.4× excess lithium as the anode was demonstrated to cycle above 130 times, at industrially significant loading of 1.83 mAh/cm2 and 0.36 C. This is attributed to the formation of a protective LiF nanolayer, which has a wide bandgap, high surface energy, and small Burgers vector, making it ductile at room temperature and less likely to rupture in electrodeposition.

  10. 19F-NMR study of fluorinated corticosteroids

    Science.gov (United States)

    Joseph-Nathan, P.; Espñeira, J.; Santillan, R. L.

    19F-NMR measurements of fluorinated corticosteroids by continuous wave time averaging at 94.1 MHz allowed specific spectral determination of the highly insoluble underivatized compounds. The wide range of chemical shifts as well as observation of 1H 19F coupling constants evidences the potential inherent in this technique for the conformational analysis of the B ring of this type of molecule.

  11. Fluorinated monovacancies in graphene: Even-odd effect

    KAUST Repository

    Kaloni, Thaneshwor P.

    2012-11-01

    The electronic and structural properties of fluorinated monovacancies in graphene are studied using density functional theory. Our calculations show that an odd number of F atoms adsorbed on a monovacancy gives rise to a p-type metallic state with a local magnetic moment of 1μ B. In contrast, an even number of F atoms leads to a non-magnetic semiconducting state. We explain the behaviour in terms of local structure properties. © Copyright EPLA, 2012.

  12. Aromatic fluorine compounds. VIII. Plant growth regulators and intermediates

    Science.gov (United States)

    Finger, G.C.; Gortatowski, M.J.; Shiley, R.H.; White, R.H.

    1959-01-01

    The preparation and properties of 41 fluorophenoxyacetic acids, 4 fluorophenoxypropionic acids, 2 fluorobenzoic acids, several indole derivatives, and a number of miscellaneous compounds are described. Data are given for many intermediates such as new fluorinated phenols, anisoles, anilines and nitrobenzenes. Most of the subject compounds are related to a number of well-known herbicides or plant growth regulators such as 2,4-D, 2,4,5-T and others.

  13. Fluorinated Analogs of Malachite Green: Synthesis and Toxicity

    Directory of Open Access Journals (Sweden)

    Bahram Parvin

    2008-04-01

    Full Text Available A series of fluorinated analogs of malachite green (MG have been synthesizedand their toxicity to Saccharomyces cerevisiae and a human ovarian epithelial cell lineexamined. The toxicity profiles were found to be different for these two species. Twoanalogs, one with 2,4-difluoro substitution and the other with 2-fluoro substitution seem tobe the most promising analogs because they showed the lowest toxicity to the human cells.

  14. Is the transition zone a deep reservoir for fluorine?

    Science.gov (United States)

    Roberge, Mathilde; Bureau, Hélène; Bolfan-Casanova, Nathalie; Frost, Daniel J.; Raepsaet, Caroline; Surble, Suzy; Khodja, Hicham; Auzende, Anne-Line; Fiquet, Guillaume

    2015-11-01

    It is now recognized that the transition zone (TZ) is a significant repository for water. This means that other volatile species may also be stored in this region such as halogen elements. We have measured the solubility of fluorine in wadsleyite (Wd) and ringwoodite (Rw) under hydrous and anhydrous conditions at different pressures and temperatures, relevant for the transition zone. F contents are similar in Wd (665 to 1045 ppm F, up to 956 ppm H2O) and in Rw (186 to 1235 ppm F, up to 1404 ppm H2O). This suggests that F may be incorporated in the same manner as water in the major nominally anhydrous minerals of the TZ: ringwoodite and wadsleyite and that the transition zone could be a major reservoir for fluorine. In the framework of the ;water filter model; proposed by Bercovici and Karato (2003), the contrast of volatile element contents between a depleted upper mantle and an enriched transition zone could be maintained over geological time scales. Previous estimates of the fluorine content of the Bulk Silicate Earth (BSE), such as 25 ppm by mass (McDonough and Sun, 1995), have assumed a homogeneous mantle. Although we do not know whether the TZ is F saturated or not, we used our new experimental data and estimates of the lower mantle F content from ocean island basalts to estimate a maximum BSE fluorine content of 59 ppm by mass for a hydrous, F-saturated TZ. This upper bound on the range of possible BSE F content emphasizes the challenges when explaining the origin of volatile elements in the Earth from a carbonaceous chondrite late veneer.

  15. Adsorption mechanism of different organic chemicals on fluorinated carbon nanotubes.

    Science.gov (United States)

    Li, Hao; Zheng, Nan; Liang, Ni; Zhang, Di; Wu, Min; Pan, Bo

    2016-07-01

    Multi-walled carbon nanotubes (MC) were fluorinated by a solid-phase reaction method using polytetrafluoroethylene (PTFE). The surface alteration of carbon nanotubes after fluorination (MC-F) was confirmed based on surface elemental analysis, TEM and SEM. The incorporation of F on MC surface was discussed as F incorporation on carbon defects, replacement of carboxyl groups, as well as surface coating of PTFE. The adsorption performance and mechanisms of MC-F for five kinds of representative organic compounds: sulfamethoxazole (SMX), ofloxacin (OFL), norfloxacin (NOR), bisphenol a (BPA) and phenanthrene (PHE) were investigated. Although BET-N2 surface area of the investigated CNTs decreased after fluorination, the adsorption of all five chemicals increased. Because of the glassification of MC-F surface coating during BET-N2 surface area measurement, the accessible surface area of MC-F was underestimated. Desorption hysteresis was generally observed in all the sorption systems in this study, and the desorption hysteresis of MC-F were stronger than the pristine CNTs. The enhanced adsorption of MC-F may be attributed the pores generated on the coated PTFE and the dispersed CNT aggregates due to the increased electrostatic repulsion after fluorination. The rearrangement of the bundles or diffusion of the adsorbates in MC-F inner pores were the likely reason for the strong desorption hysteresis of MC-F. The butterfly structure of BPA resulted in its high sorption and strong desorption hysteresis. The exothermic sorption character of OFL on CNTs resulted in its strong desorption hysteresis. Copyright © 2016 Elsevier Ltd. All rights reserved.

  16. Nucleophilic tetrafluoroethylation of carbonyl compounds with fluorinated sulfones

    Czech Academy of Sciences Publication Activity Database

    Václavík, Jiří; Chernykh, Yana; Jurásek, Bronislav; Beier, Petr

    2015-01-01

    Roč. 169, Jan (2015), s. 24-31 ISSN 0022-1139 R&D Projects: GA ČR GAP207/11/0421 Grant - others:GA MŠk(CZ) ED3.2.00/08.0144; GA MŠk(CZ) LM2010005 Institutional support: RVO:61388963 Keywords : fluorine * tetrafluoroethylation * sulfones * nucleophilic addition * carbonyl compounds Subject RIV: CC - Organic Chemistry Impact factor: 2.213, year: 2015

  17. Experimental study on thermal conductivity of free-standing fluorinated single-layer graphene

    Science.gov (United States)

    Narasaki, Masahiro; Wang, Haidong; Nishiyama, Takashi; Ikuta, Tatsuya; Takahashi, Koji

    2017-08-01

    We measured the thermal conductivity of free-standing fluorinated single-layer graphene (FSLG) using a precise T-type method. Pristine graphene was fluorinated and suspended above the substrate using xenon difluoride gas. Compared with the thermal conductivity of pristine single-layer graphene (SLG) (˜2000 W/mK) previously measured by the same T-type method for the same original SLG, the FSLG exhibited a much lower thermal conductivity (˜80 W/mK) and a weak dependence of the thermal conductivity on nanohole defects. The experimental results suggest that the fluorine atoms and sp3 bonding in the FSLG strongly contributed to phonon scattering. The phonon scattering by the fluorine atoms and sp3 bonding has a dominant effect on the thermal conductivity decrease over the phonon scattering by nanohole defects. This study lays a foundation for the thermal measurement of 2D fluorinated materials and benefits future applications of fluorinated graphene.

  18. Hydrogen-bond promoted nucleophilic fluorination: concept, mechanism and applications in positron emission tomography.

    Science.gov (United States)

    Lee, Ji-Woong; Oliveira, Maria Teresa; Jang, Hyeong Bin; Lee, Sungyul; Chi, Dae Yoon; Kim, Dong Wook; Song, Choong Eui

    2016-08-22

    Due to the tremendous interest in carbon-fluorine bond-forming reactions, research efforts in this area have been dedicated to the development of facile processes to synthesize small fluorine-containing organic molecules. Among others, PET (Positron Emission Tomography) is one of the most important applications of fluorine chemistry. Recognizing the specific requirements of PET processes, some groups have focused on fluorination reactions using alkali metal fluorides, particularly through SN2-type reactions. However, a common "misconception" about the role of protic solvents and hydrogen bonding interactions in this class of reactions has hampered the employment of these excellent promoters. Herein, we would like to review recent discoveries in this context, showing straightforward nucleophilic fluorination reactions using alkali metal fluorides promoted by protic solvents. Simultaneous dual activation of reacting partners by intermolecular hydrogen bonding and the enhancement of the "effective fluoride nucleophilicity", which is Nature's biocatalytic approach with the fluorinase enzyme, are the key to this unprecedentedly successful nucleophilic fluorination.

  19. A fluorinated dendrimer achieves excellent gene transfection efficacy at extremely low nitrogen to phosphorus ratios

    Science.gov (United States)

    Wang, Mingming; Liu, Hongmei; Li, Lei; Cheng, Yiyun

    2014-01-01

    Polymers have shown great promise in the design of high efficient and low cytotoxic gene vectors. Here we synthesize fluorinated dendrimers for use as gene vectors. Fluorinated dendrimers achieve excellent gene transfection efficacy in several cell lines (higher than 90% in HEK293 and HeLa cells) at extremely low N/P ratios. These polymers show superior efficacy and biocompatibility compared with several commercial transfection reagents such as Lipofectamine 2000 and SuperFect. Fluorination enhances the cellular uptake of the dendrimer/DNA polyplexes and facilitates their endosomal escape. In addition, the fluorinated dendrimer shows excellent serum resistance and exhibits high gene transfection efficacy even in medium containing 50% FBS. The results suggest that fluorinated dendrimers are a new class of highly efficient gene vectors and fluorination is a promising strategy to design gene vectors without involving sophisticated syntheses.

  20. Polymeric salt bridges for conducting electric current in microfluidic devices

    Science.gov (United States)

    Shepodd, Timothy J [Livermore, CA; Tichenor, Mark S [San Diego, CA; Artau, Alexander [Humacao, PR

    2009-11-17

    A "cast-in-place" monolithic microporous polymer salt bridge for conducting electrical current in microfluidic devices, and methods for manufacture thereof is disclosed. Polymeric salt bridges are formed in place in capillaries or microchannels. Formulations are prepared with monomer, suitable cross-linkers, solvent, and a thermal or radiation responsive initiator. The formulation is placed in a desired location and then suitable radiation such as UV light is used to polymerize the salt bridge within a desired structural location. Embodiments are provided wherein the polymeric salt bridges have sufficient porosity to allow ionic migration without bulk flow of solvents therethrough. The salt bridges form barriers that seal against fluid pressures in excess of 5000 pounds per square inch. The salt bridges can be formulated for carriage of suitable amperage at a desired voltage, and thus microfluidic devices using such salt bridges can be specifically constructed to meet selected analytical requirements.

  1. Dipolar rotors orderly aligned in mesoporous fluorinated organosilica architectures

    KAUST Repository

    Bracco, Silvia

    2015-02-16

    New mesoporous covalent frameworks, based on hybrid fluorinated organosilicas, were prepared to realize a periodic architecture of fast molecular rotors containing dynamic dipoles in their structure. The mobile elements, designed on the basis of fluorinated p-divinylbenzene moieties, were integrated into the robust covalent structure through siloxane bonds, and showed not only the rapid dynamics of the aromatic rings (ca. 108 Hz at 325 K), as detected by solid-state NMR spectroscopy, but also a dielectric response typical of a fast dipole reorientation under the stimuli of an applied electric field. Furthermore, the mesochannels are open and accessible to diffusing in gas molecules, and rotor mobility could be individually regulated by I2 vapors. The iodine enters the channels of the periodic structure and reacts with the pivotal double bonds of the divinyl-fluoro-phenylene rotors, affecting their motion and the dielectric properties. Oriented molecular rotors: Fluorinated molecular rotors (see picture) were engineered in mesoporous hybrid organosilica architectures with crystalline order in their walls. The rotor dynamics was established by magic angle spinning NMR and dielectric measurements, indicating a rotational correlation time as short as 10-9 s at 325 K. The dynamics was modulated by I2 vapors entering the pores.

  2. External-beam PIGE for fluorine determination in atmospheric aerosol

    Science.gov (United States)

    Calastrini, F.; Del Carmine, P.; Lucarelli, F.; Mandò, P. A.; Prati, P.; Zucchiatti, A.

    1998-03-01

    Air pollution measurements have been performed at Montelupo, a town about 20 km west of Florence, characterised by the presence of a large number of ceramic and glass factories just inside the inhabited area. Both filters collecting aerosols during 24 h and streaker filters with 1-h resolution capability have been analysed, using external Particle Induced X-ray Emission (PIXE) and Proton-Induced Gamma-Ray Emission (PIGE) simultaneously. The best operating conditions for getting quantitative information from the PIGE analysis of fluorine in the external beam set-up have been investigated. The minimum detection limit for the concentration of fluorine in air is in the order of 10 ng/m 3. Some specific results concerning fluorine determination in both the 24 and 1-h resolution measurements are finally presented. While the average detected concentrations in air come out to be well below the air quality limits, time episodes of relatively higher concentration have been detected and thanks to the time correlation with the other elements the origin of these pollution episodes can be hypothesised with a good degree of confidence.

  3. Fluorinated graphene films with graphene quantum dots for electronic applications

    Energy Technology Data Exchange (ETDEWEB)

    Antonova, I. V., E-mail: antonova@isp.nsc.ru [Rzhanov Institute of Semiconductor Physics, Russian Academy of Sciences, Siberian Branch, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Nebogatikova, N. A.; Prinz, V. Ya. [Rzhanov Institute of Semiconductor Physics, Russian Academy of Sciences, Siberian Branch, Novosibirsk 630090 (Russian Federation)

    2016-06-14

    This work analyzes carrier transport, the relaxation of non-equilibrium charge, and the electronic structure of fluorinated graphene (FG) films with graphene quantum dots (GQDs). The FG films with GQDs were fabricated by means of chemical functionalization in an aqueous solution of hydrofluoric acid. High fluctuations of potential relief inside the FG barriers have been detected in the range of up to 200 mV. A phenomenological expression that describes the dependence of the time of non-equilibrium charge emission from GQDs on quantum confinement levels and film thickness (potential barrier parameters between GQDs) is suggested. An increase in the degree of functionalization leads to a decrease in GQD size, the removal of the GQD effect on carrier transport, and the relaxation of non-equilibrium charge. The study of the electronic properties of FG films with GQDs has revealed a unipolar resistive switching effect in the films with a relatively high degree of fluorination and a high current modulation (up to ON/OFF ∼ 10{sup 4}–10{sup 5}) in transistor-like structures with a lower degree of fluorination. 2D films with GQDs are believed to have considerable potential for various electronic applications (nonvolatile memory, 2D connections with optical control and logic elements).

  4. Development of Fluorinated Non-Peptidic Ghrelin Receptor Ligands for Potential Use in Molecular Imaging

    Directory of Open Access Journals (Sweden)

    Rareş-Petru Moldovan

    2017-04-01

    Full Text Available The ghrelin receptor (GhrR is a widely investigated target in several diseases. However, the current knowledge of its role and distribution in the brain is limited. Recently, the small and non-peptidic compound (S-6-(4-bromo-2-fluorophenoxy-3-((1-isopropylpiperidin-3-ylmethyl-2-methylpyrido[3,2-d]pyrimidin-4(3H-one ((S-9 has been described as a GhrR ligand with high binding affinity. Here, we describe the synthesis of fluorinated derivatives, the in vitro evaluation of their potency as partial agonists and selectivity at GhrRs, and their physicochemical properties. These results identified compounds (S-9, (R-9, and (S-16 as suitable parent molecules for 18F-labeled positron emission tomography (PET radiotracers to enable future investigation of GhrR in the brain.

  5. Route to sustainable lithium-sulfur batteries with high practical capacity through a fluorine free polysulfide catholyte and self-standing Carbon Nanofiber membranes.

    Science.gov (United States)

    Lim, Du-Hyun; Agostini, Marco; Nitze, Florian; Manuel, James; Ahn, Jou-Hyeon; Matic, Aleksandar

    2017-07-24

    We report on a new strategy to improve the capacity, reduce the manufacturing costs and increase the sustainability of Lithium-Sulfur (LiS) batteries. It is based on a semi-liquid cathode composed of a Li2S8 polysulphide catholyte and a binder-free carbon nanofiber membrane with tailored morphology. The polysulphides in the catholyte have the dual role of active material and providing Li+-conduction, i.e. no traditional Li-salt is used in this cell. The cell is able to deliver an areal capacity as high as 7 mAh cm-2, twice than that of commercial Lithium-ion batteries (LiBs) and 2-4 times higher than that of state-of-the-art LiS cells. In addition, the battery concept has an improved sustainability from a material point of view by being mainly based on sulfur and carbon and being completely fluorine-free, no fluorinated salt or binders are used, and has potential for upscaling and competitive price. The combination of these properties makes the semi-liquid LiS cell here reported a very promising new concept for practical large-scale energy storage applications.

  6. Novel fluorinated ligands for gold nanoparticle labelling with application in 19F-MRI.

    OpenAIRE

    Michelena Olatz; Padro Daniel; Carrillo-Carrión Carolina; del Pino Pablo; Blanco Jorge; Arnáiz Blanca; Parak Wolfgang J.; Carril Monica

    2017-01-01

    Novel fluorinated ligands for gold nanoparticle labelling have been designed and synthesised. Several types of gold nanoparticles have been prepared in the presence of these fluorinated ligands alone, or in combination with non-fluorinated ligands. Their colloidal stability in water and other solvents was tested and the magnetic resonance properties of the so-obtained nanoparticles were also assessed in detail. H-1 and F-19-NMR spectra were evaluated and MRI phantoms of the most promising nan...

  7. Liquid salt environment stress-rupture testing

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Weiju; Holcomb, David E.; Muralidharan, Govindarajan; Wilson, Dane F.

    2016-03-22

    Disclosed herein are systems, devices and methods for stress-rupture testing selected materials within a high-temperature liquid salt environment. Exemplary testing systems include a load train for holding a test specimen within a heated inert gas vessel. A thermal break included in the load train can thermally insulate a load cell positioned along the load train within the inert gas vessel. The test specimen can include a cylindrical gage portion having an internal void filled with a molten salt during stress-rupture testing. The gage portion can have an inner surface area to volume ratio of greater than 20 to maximize the corrosive effect of the molten salt on the specimen material during testing. Also disclosed are methods of making a salt ingot for placement within the test specimen.

  8. Contributions on the diagnosis of fluorine damage. I. Fluorine damage in indicator plants in the wild flora

    Energy Technology Data Exchange (ETDEWEB)

    Borsdorf, W.

    1960-01-01

    In an area of Central Germany affected by gaseous waste containing fluorine, the wild flora and some cultivated plants were investigated as to their suitability as indicators of fluorine pollution. As a result of three years of observation a list of 59 species is presented, four susceptibility groups being distinguished on the basis of the macroscopic symptoms of the damage (necrosis on the leaf tips and margins, less frequently in the zones between the ribs). Vitis vinifera L., Carpinus betula L., Iris germanica L., Arrenatherum clatius (L.) J.u.C. Presl and Dactylis glomenata L. proved to be extremely sensitive. The intensity of the symptoms is influenced, among other things, by a number of environmental factors (topographic features, predominant direction of winds, precipitation and degree of afforestation). 6 references.

  9. Enhanced Selectivity and Uptake Capacity of CO2 and Toluene Adsorption in Co0.5 M0.33 MoS4 (M= Sb or Y) Chalcogels by Impregnated Metal Salts

    KAUST Repository

    Adhiam, Fatima Abdullah Ahmed

    2017-11-17

    The synthesis of metal chalcogenide aerogels Co0.5M0.33MoS4 (M= Sb or Y) by the sol-gel method is reported. In this system, the building blocks [MoS4]2− chelated with Co2+ and (Sb3+) or (Y3+) salts in nonaqueous solvents forming amorphous networks with a gel property. The chalcogels obtained after supercritical drying have BET surface areas of 176 m2 g−1 (Co0.5Sb0.33MoS4) and 145 m2 g−1 (Co0.5Y0.33MoS4). Electron microscopy and physisorption studies reveal that the new materials are porous with wide pore size distribution and average pore width of 16 nm. These chalcogels show higher adsorption capacity of toluene vapor (Co0.5Sb0.33MoS4: 387 mg g−1) and (Co0.5Y0.33MoS4: 304 mg g−1) over cyclohexane vapor and high selectivity of CO2 over CH4 or H2, Co0.5Sb0.33MoS4 (CO2/H2: 80 and CO2/CH4: 21), Co0.5Y0.33MoS4 (CO2/H2: 27 and CO2/CH4: 15). We also demonstrated that the impregnation of various metal species like Li+, Mg2+, and Ni2+ significantly enhanced the uptake capacity and selectivity of toluene and CO2 adsorptions in the chacogels.

  10. Chemical Makeup and Hydrophilic Behavior of Graphene Oxide Nanoribbons after Low-Temperature Fluorination.

    Science.gov (United States)

    Romero Aburto, Rebeca; Alemany, Lawrence B; Weldeghiorghis, Thomas K; Ozden, Sehmus; Peng, Zhiwei; Lherbier, Aurélien; Botello Méndez, Andrés Rafael; Tiwary, Chandra Sekhar; Taha-Tijerina, Jaime; Yan, Zheng; Tabata, Mika; Charlier, Jean-Christophe; Tour, James M; Ajayan, Pulickel M

    2015-07-28

    Here we investigated the fluorination of graphene oxide nanoribbons (GONRs) using H2 and F2 gases at low temperature, below 200 °C, with the purpose of elucidating their structure and predicting a fluorination mechanism. The importance of this study is the understanding of how fluorine functional groups are incorporated in complex structures, such as GONRs, as a function of temperature. The insight provided herein can potentially help engineer application-oriented materials for several research and industrial sectors. Direct (13)C pulse magic angle spinning (MAS) nuclear magnetic resonance (NMR) confirmed the presence of epoxy, hydroxyl, ester and ketone carbonyl, tertiary alkyl fluorides, as well as graphitic sp(2)-hybridized carbon. Moreover, (19)F-(13)C cross-polarization MAS NMR with (1)H and (19)F decoupling confirmed the presence of secondary alkyl fluoride (CF2) groups in the fluorinated graphene oxide nanoribbon (FGONR) structures fluorinated above 50 °C. First-principles density functional theory calculations gained insight into the atomic arrangement of the most dominant chemical groups. The fluorinated GONRs present atomic fluorine percentages in the range of 6-35. Interestingly, the FGONRs synthesized up to 100 °C, with 6-19% of atomic fluorine, exhibit colloidal similar stability in aqueous environments when compared to GONRs. This colloidal stability is important because it is not common for materials with up to 19% fluorine to have a high degree of hydrophilicity.

  11. Recent Advances in the One-Step Synthesis of Distally Fluorinated Ketones.

    Science.gov (United States)

    Zeng, Yuwen; Ni, Chuanfa; Hu, Jinbo

    2016-03-01

    Fluorinated ketones are intriguing compounds in synthetic chemistry and life science-related fields. The development of efficient methodologies to obtain these compounds is of significant importance and has therefore attracted considerable attention. This Minireview highlights recent progress made in the synthesis of fluorine-containing ketones, with an emphasis on those methods in which the construction of carbonyl groups is synergetic with distal (β-, γ-, δ-, etc.) incorporation of fluorine atoms or fluorinated groups. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Electrochemical Fluorination and Radiofluorination of Methyl(phenylthio)acetate Using Tetrabutylammonium Fluoride (TBAF).

    Science.gov (United States)

    Balandeh, Mehrdad; Waldmann, Christopher; Shirazi, Daniela; Gomez, Adrian; Rios, Alejandra; Allison, Nathanael; Khan, Asad; Sadeghi, Saman

    2017-01-01

    Electrochemical fluorination of methyl(phenylthio)acetate was achieved using tetrabutylammonium fluoride (TBAF). Electrochemical fluorination was performed under potentiostatic anodic oxidation using an undivided cell in acetonitrile containing TBAF and triflic acid. The influence of several parameters including: oxidation potential, time, temperature, sonication, TBAF concentration and triflic acid concentration on fluorination efficiency were studied. It was found that the triflic acid to TBAF concentration ratio plays a key role in the fluorination efficiency. Electrochemical fluorination resulted in formation of mono-fluorinated methyl 2-fluoro-2-(phenylthio)acetate verified by gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) Spectroscopy. Under optimum conditions 44 ± 3% mono fluorination yield was obtained after a 30 min electrolysis. Electrochemical radiofluorination for the synthesis of methyl 2-[18F]fluoro-2-(phenothio) acetate was also achieved with the same optimized electrochemical cell parameters where TBAF was first passed through an anion exchange resin containing fluorine-18. A radiochemical fluorination efficiency of 7 ± 1% was achieved after 30 min of electrolysis.

  13. Fluorine follows water: Effect on electrical conductivity of silicate minerals by experimental constraints from phlogopite

    Science.gov (United States)

    Li, Yan; Jiang, Haotian; Yang, Xiaozhi

    2017-11-01

    Fluorine and hydroxyl groups are minor constituents of silicate minerals, and share a lot of similarities concerning their physical and chemical properties. Hydroxyl groups significantly enhance the electrical conductivity of many silicate minerals, and it is expected that fluorine would have a comparable effect. This, however, has never been documented quantitatively. Here we present experimental approaches on this issue, by investigating the electrical conductivity of phlogopite with a wide range of fluorine content (but with broadly similar contents for other major elements). Electrical conductivities of gem-quality single crystal phlogopites, with samples prepared along the same orientation (normal to the (0 0 1) plane), were determined at 1 GPa and 200-650 °C using an end-loaded piston cylinder apparatus and a Solartron-1260 Impedance/Gain Phase Analyzer over the frequency range of 106 to 0.1 Hz. The complex spectra usually show an arc in the high frequency range and a short tail in the low frequency range, which are caused by lattice conduction and electrode effects, respectively. The electrical conductivity increases with increasing fluorine content, and the main charge carriers are fluorine. The activation enthalpies are ∼180 to 200 kJ/mol, nearly independent of fluorine content. The conductivity is linearly proportional to the content of fluorine, with an exponent factor of ∼1. The results demonstrate that conduction by fluorine leads to very high electrical conductivity at high temperatures. The influence of fluorine on electrical conductivity may be compared to that of hydrogen in nominally anhydrous minerals. This, along with the close association of fluorine and hydroxyl groups in silicate minerals and their similar crystal-chemical behaviors, suggests a more general role of fluorine in enhancing the electrical conductivity of many silicate minerals. Fluorine-rich assemblages, e.g., phlogopite and amphibole, could be locally enriched in the upper

  14. Solid phase synthesis of peptides containing backbone-fluorinated amino acids.

    Science.gov (United States)

    Hunter, Luke; Butler, Sharon; Ludbrook, Steven B

    2012-11-28

    Backbone-fluorinated amino acids exhibit unique conformational behaviour, and have potential utility as components of bioactive shape-controlled peptides. However, methods for the elaboration of backbone-fluorinated amino acids have thus far been limited to solution phase peptide coupling reactions. In this paper, protocols are developed that allow the successful manipulation of backbone-fluorinated amino acids using Fmoc-strategy solid phase peptide synthesis. To exemplify this strategy, several fluorinated RGD peptide analogues were synthesised in moderate to good overall yields.

  15. Hydroxycarboxylic acids and salts

    Energy Technology Data Exchange (ETDEWEB)

    Kiely, Donald E; Hash, Kirk R; Kramer-Presta, Kylie; Smith, Tyler N

    2015-02-24

    Compositions which inhibit corrosion and alter the physical properties of concrete (admixtures) are prepared from salt mixtures of hydroxycarboxylic acids, carboxylic acids, and nitric acid. The salt mixtures are prepared by neutralizing acid product mixtures from the oxidation of polyols using nitric acid and oxygen as the oxidizing agents. Nitric acid is removed from the hydroxycarboxylic acids by evaporation and diffusion dialysis.

  16. SALT for Language Acquisition.

    Science.gov (United States)

    Bancroft, W. Jane

    1996-01-01

    Discusses Schuster's Suggestive-Accelerative Learning Techniques (SALT) Method, which combines Lozanov's Suggestopedia with such American methods as Asher's Total Physical Response and Galyean's Confluent Education. The article argues that students trained with the SALT Method have higher achievement scores and better attitudes than others. (14…

  17. Self-Assembly of Fluorinated Sugar Amino Acid Derived α,γ-Cyclic Peptides into Transmembrane Anion Transport.

    Science.gov (United States)

    Burade, Sachin S; Saha, Tanmoy; Bhuma, Naresh; Kumbhar, Navanath; Kotmale, Amol; Rajamohanan, Pattuparambil R; Gonnade, Rajesh G; Talukdar, Pinaki; Dhavale, Dilip D

    2017-11-03

    Syntheses of fluorinated sugar amino acid derived α,γ-cyclic tetra- and hexapeptides are reported. The IR, NMR, ESI-MS, CD, and molecular modeling studies of cyclic tetra- and hexapeptides showed C 2 and C 3 symmetric flat oval- and triangular-ring shaped β-strand conformations, respectively, which appear to self-assemble into nanotubes. The α,γ-cyclic hexapeptide (EC 50 = 2.14 μM) is found to be a more efficient ion transporter than α,γ-cyclic tetrapeptide (EC 50 = 14.75 μM). The anion selectivity and recognition of α,γ-cyclic hexapeptide with NO 3 - ion is investigated.

  18. Resedimented salt deposits

    Energy Technology Data Exchange (ETDEWEB)

    Slaczka, A.; Kolasa, K. (Jagiellonian Univ., Krakow (Poland))

    1988-08-01

    Carparthian foredeep's Wieliczka salt mine, unique gravity deposits were lately distinguished. They are mainly built of salt particles and blocks with a small admixture of fragments of Miocene marls and Carpathian rocks, deposited on precipitated salt. The pattern of sediment distribution is similar to a submarine fan. Gravels are dominant in the upper part and sands in lower levels, creating a series of lobes. Coarse-grained deposits are represented by disorganized, self-supported conglomerates passing into matrix-supported ones, locally with gradation, and pebbly sandstones consisting of salt grains and scattered boulder-size clasts. The latter may show in the upper part of a single bed as indistinct cross-bedding and parallel lamination. These sediments are interpreted as debris-flow and high-density turbidity current deposits. Salt sandstones (saltstones) which build a lower part of the fan often show Bouma sequences and are interpreted as turbidity-current deposits. The fan deposits are covered by a thick series of debrites (olistostromes) which consist of clay matrix with salt grains and boulders. The latter as represented by huge (up to 100,000 m{sup 3}) salt blocks, fragments of Miocene marls and Carpathian rocks. These salt debrites represent slumps and debris-flow deposits. The material for resedimented deposits was derived from the southern part of the salt basin and from the adjacent, advancing Carpathian orogen. The authors believe the distinct coarsening-upward sequence of the series is the result of progressive intensification of tectonic movements with paroxysm during the sedimentation of salt debrites (about 15 Ma).

  19. Water purification using organic salts

    Science.gov (United States)

    Currier, Robert P.

    2004-11-23

    Water purification using organic salts. Feed water is mixed with at least one organic salt at a temperature sufficiently low to form organic salt hydrate crystals and brine. The crystals are separated from the brine, rinsed, and melted to form an aqueous solution of organic salt. Some of the water is removed from the aqueous organic salt solution. The purified water is collected, and the remaining more concentrated aqueous organic salt solution is reused.

  20. Synthesis of a metabolically stable modified long-chain fatty acid salt and its photolabile derivative

    Energy Technology Data Exchange (ETDEWEB)

    Stoll, G.H.; Voges, R.; Gerok, W.; Kurz, G. (Institut fuer Organische Chemie and Biochemie, Universitaet Freiburg (Germany))

    1991-05-01

    An analogue of the long-chain fatty acid salt, sodium stearate, was synthesized in which the hydrogen atoms at carbons 2, 3, and 18 were replaced by fluorine. The key step in the synthesis was the addition of 3-iodo-2,2,3,3-tetrafluoropropanoic acid amide to 15,15,15-trifluoro-1-pentadecene. Radioactivity was introduced by catalytic reduction of 2,2,3,3,18,18,18-heptafluoro-4-octadecenoic acid amide with carrier-free tritium gas yielding a product with the specific radioactivity of 2.63 TBq/mmol. The resulting 2,2,3,3,18,18,18-heptafluoro-4-octadecenoic acid has a pKa of about 0.5 and is completely dissociated under normal physiological conditions. The fluorinated fatty acid salt analogue is readily taken up into hepatocytes and proved to be metabolically inert. In an approach to the identification of proteins involved in long-chain fatty acid salt transport across membranes and intracellular compartments, the photolabile derivative 11,11-azo-2,2,3,3,18,18,18-heptafluoro(G-3H)octadecanoic acid sodium salt was synthesized with a specific radioactivity of 2.63 TBq/mmol. Photolysis of the photolabile derivative, using a light source with a maximum emission at 350 nm, occurred with a half-life of 1.5 min. The generated carbene reacted with 14C-labeled methanol and acetonitrile with covalent bond formation of 6-13%. Its efficacy for photoaffinity labeling was demonstrated by incorporation into serum albumin, the extracellular fatty acid salt-binding protein, as well as into the intracellular fatty acid salt-binding protein (FABP) of rat liver with the molecular weight of 14,000.

  1. A Highly Selective Photoresist Ashing Process for Silicon Nitride Films by Addition of Trifluoromethane

    Science.gov (United States)

    Saito, Makoto; Eto, Hideo; Makino, Nobuaki; Omiya, Kayoko; Homma, Tetsuya; Nagatomo, Takao

    2001-09-01

    A highly selective photoresist ashing process was developed for the fabrication of thin-film transistor liquid-crystal displays (TFT-LCDs). This ashing process utilizes downflow plasma consisting of a carbon trifluoromethane/oxygen (CHF3/O2) gas mixture at a low temperature. The etching selectivity of photoresist films to silicon nitride (SiN) film increased when using the CHF3/O2 gas mixture plasma, as compared to that when using the carbon tetrafluoride/oxygen (CF4/O2) gas mixture plasma. At the CHF3 gas flow rate of 30 sccm, a high etching selectivity ratio of about 1080 for the photoresist films to the SiN films was achieved at room temperature. On the basis of surface analysis results for SiN films and plasma analysis results for the CHF3/O2 gas mixture, a mechanism for the high etching selectivity of the photoresist films was proposed. Reaction products that were formed on SiN films by the CHF3/O2 gas mixture plasma obstructed the etching of SiN films by fluorine (F) radicals, resulting in the high selectivity. It was found that the CHF3/O2 gas mixture plasma reacted with SiN, resulting in the formation of a protective reaction product that is considered to be an ammonium salt such as (NH4)2SiF6.

  2. Gases in molten salts

    CERN Document Server

    Tomkins, RPT

    1991-01-01

    This volume contains tabulated collections and critical evaluations of original data for the solubility of gases in molten salts, gathered from chemical literature through to the end of 1989. Within the volume, material is arranged according to the individual gas. The gases include hydrogen halides, inert gases, oxygen, nitrogen, hydrogen, carbon dioxide, water vapor and halogens. The molten salts consist of single salts, binary mixtures and multicomponent systems. Included also, is a special section on the solubility of gases in molten silicate systems, focussing on slags and fluxes.

  3. Detection and removal of molten salts from molten aluminum alloys

    Energy Technology Data Exchange (ETDEWEB)

    K. Butcher; D. Smith; C. L. Lin; L. Aubrey

    1999-08-02

    Molten salts are one source of inclusions and defects in aluminum ingots and cast shapes. A selective adsorption media was used to remove these inclusions and a device for detection of molten salts was tested. This set of experiments is described and the results are presented and analyzed.

  4. Classification and salt tolerance analysis of barley varieties

    NARCIS (Netherlands)

    Katerji, N.; Hoorn, van J.W.; Hamdy, A.; Mastrorilli, M.; Fares, C.; Ceccarelli, S.; Grando, S.; Oweis, T.

    2006-01-01

    Six varieties of barley (Hordeum vulgare), five of which were provided by ICARDA, were tested in a green house experiment for their salt tolerance. Afterwards the ICARDA variety Melusine, selected from this experiment for its combination of high yield and salt tolerance, was compared in a lysimeter

  5. Self-assembly and omniphobic property of fluorinated unit end-functionalized poly(methyl methacrylate)

    Science.gov (United States)

    Junyan, Liang; Pingdi, Xu; Jingxian, Bao; Ling, He; Nan, Zhu

    2018-03-01

    The self-assembly behavior of fluorinated unit end-functionalized poly(methyl methacrylate) (PDFHM-ef-PMMA) in solution and its influence on the surface microstructure, elemental composition and omniphobic property of cast film was investigated in this work. Specifically, three mixed solutions of tetrahydrofuran (THF)/methanol (MeOH), THF/H2O and THF/H2O/MeOH in various compositions were employed separately as the selective solvents. In THF/MeOH solution, the aggregate morphologies of PDFHM-ef-PMMA changed gradually from core-shell spheres to worm, and then to elliptical vesicles as MeOH content increased. In THF/H2O solution, spherical and bowl-shaped aggregates with significantly larger sizes than those in THF/MeOH solution were favored despite lower H2O content. The further addition of MeOH to THF/H2O mixture could reduce the size of aggregate but hardly change original aggregate morphology. During the film formation process, those self-assembled aggregates in THF/MeOH solution fused with one another to form a smooth surface. When such surface was fully covered by fluorinated segments, the outstanding hexadecane and water slide-off properties and ink-resistant property required for antifouling application were demonstrated. Instead, the aggregates formed in THF/H2O/MeOH mixture were subjected to secondary aggregation of PDFHM-ef-PMMA chains during solvent evaporation, leading to the formation of a particulate film with poor adhesion towards glass plate and hexadecane-repellent property.

  6. A review of SiC reactive ion etching in fluorinated plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Yih, P.H. [Bell Labs., Orlando, FL (United States). Lucent Technologies; Saxena, V.; Steckl, A.J. [Cincinnati Univ., OH (United States). Dept. of Electrical and Computer Engineering

    1997-07-01

    Research and development in semiconducting silicon carbide (SiC) technology has produced significant progress in the past five years in many areas: material (bulk and thin film) growth, device fabrication, and applications. A major factor in this rapid growth has been the development of SiC bulk crystals and the availability of crystalline substrates. Current leading applications for SiC devices include high power and high temperature devices and light emitting diodes. Due to the strong bonding between Si and C (Si-C = 1.34 x Si-Si), wet chemical etching can only be performed at high temperature. Therefore, plasma-based (``dry``) etching plays the crucial role of patterning SiC for the fabrication of various electronic devices. In the past several years, reactive ion etching (RIE) of SiC polytypes (3C and 6H) has been investigated in fluorinated gases (primarily CHF{sub 3}, CBrF{sub 3}, CF{sub 4}, SF{sub 6}, and NF{sub 3}), usually mixed with oxygen and occasionally with other additives or in a mixture of fluorinated gases. In this paper, a review of SiC RIE is presented. The primary emphasis is on etching of the 3C and 6H polytypes, but some results on RIE of the 4H polytype are included. The paper covers the basic etching mechanisms, provides typical etching properties in selected plasma conditions, discusses the effects of changes in various etching parameters, such as plasma pressure, density and power, etching time, etc. The etching of features of sizes varying from sub-{mu}m to tens of {mu}m`s is addressed. Finally, optimum etching conditions and trade-offs are considered for various device configurations. (orig.) 122 refs.

  7. A Review of SiC Reactive Ion Etching in Fluorinated Plasmas

    Science.gov (United States)

    Yih, P. H.; Saxena, V.; Steckl, A. J.

    1997-07-01

    Research and development in semiconducting silicon carbide (SiC) technology has produced significant progress in the past five years in many areas: material (bulk and thin film) growth, device fabrication, and applications. A major factor in this rapid growth has been the development of SiC bulk crystals and the availability of crystalline substrates. Current leading applications for SiC devices include high power and high temperature devices and light emitting diodes. Due to the strong bonding between Si and C (Si-C = 1.34×Si-Si), wet chemical etching can only be performed at high temperature. Therefore, plasma-based (dry) etching plays the crucial role of patterning SiC for the fabrication of various electronic devices. In the past several years, reactive ion etching (RIE) of SiC polytypes (3C and 6H) has been investigated in fluorinated gases (primarily CHF3, CBrF3, CF4, SF6, and NF3), usually mixed with oxygen and occasionally with other additives or in a mixture of fluorinated gases. In this paper, a review of SiC RIE is presented. The primary emphasis is on etching of the 3C and 6H polytypes, but some results on RIE of the 4H polytype are included. The paper covers the basic etching mechanisms, provides typical etching properties in selected plasma conditions, discusses the effects of changes in various etching parameters, such as plasma pressure, density and power, etching time, etc. The etching of features of sizes varying from sub-m to tens of μm's is addressed. Finally, optimum etching conditions and trade-offs are considered for various device configurations.

  8. Expedited Synthesis of Fluorine-18 Labeled Phenols. A Missing Link in PET Radiochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Katzenellenbogen, John A. [Univ. of Illinois, Champaign, IL (United States); Zhou, Dong [Washington Univ., St. Louis, MO (United States)

    2015-03-26

    (diazocyclohexenones) by a novel reaction sequence that uses fluoride ion as a precursor and various activating electrophiles, and we have improved methods for the preparation of heterodiaryl iodonium salts. Both methods have been used to prepare interesting potential radiotracers. Other advances have been made in labeling dendrimeric nanoparticle structures of increasing interest for multimodal imaging and in advancing labeling through fluorosilane bonds. Thus, the progress we have made substantially fills the significant gap in PET radiochemistry that we originally identified, and it provides for the field new methodology that can be applied to a number of current challenges, including the preparation of several molecules of interest as radiotracers, such as 2-[18F]Fluoroestradiol (2-FES) and m-fluorotyrosine, which we have illustrated. These methods can be used by any skilled radiochemist interesting in preparing these agents or similar fluorine-18 labeled electron-rich arene systems of interested for PET biological imaging in the most general sense.

  9. Partially fluorinated arylene polyethers and their ternary blend membranes with PBI and H3PO4

    DEFF Research Database (Denmark)

    Kerres, J.; Schonberger, F.; Chromik, A

    2008-01-01

    A partially fluorinated polyether ionomer from polycondensation of decafluorobiphenyl with 2,2-bis(4-hydroxyphenyl)-hexafluoropropane, followed by sulphonation with H2SO4 (60% SO3), has been prepared and optimised in terms of molecular weight and sulphonation degree. The partially fluorinated ion...

  10. THE HEAT CAPACITY OF FLUORINATED PROPANE AND BUTANE DERIVATIVES BY DIFFERENTIAL SCANNING CALORIMETRY

    Science.gov (United States)

    The paper gives results of the measurement (to 3% accuracy) of the constant-pressure liquid-phase heat capacities of 21 hydrogen-containing fluorinated propane and butane derivatives and one fluorinated ether (CF3OCF2H) with boiling points ranging from -34.6 to 76.7 C, using diff...

  11. Proton Exchange Membrane Fuel Cell With Enhanced Durability Using Fluorinated Carbon As Electrocatalyst

    Directory of Open Access Journals (Sweden)

    Ahmad Yasser

    2017-01-01

    Full Text Available This study evaluates the fluorination of a carbon aerogel and its effects on the durability of the resulting electrocatalyst for Proton Exchange Membrane Fuel Cell (PEMFC. Fluorine has been introduced before or after platinum deposition. The different electrocatalysts are physico-chemically and electrochemically characterized, and the results discussed by comparison with commercial Pt/XC72 from E-Tek. The results demonstrate that the level of fluorination of the carbon aerogel can be controlled. The fluorination modifies the texture of the carbons by increasing the pore size and decreasing the specific surface area, but the textures remain appropriate for PEMFC applications. Two fluorination sites are observed, leading to both high covalent C-F bond and weakened ones, the quantity of which depends on whether the treatment is done before or after platinum deposition. The order of the different treatments is very important. The presence of platinum contributes to the fluorination mechanism, but leads to amorphous platinum rather inactive towards the Oxygen Reduction Reaction. Finally, a better durability was demonstrated for the fluorinated then platinized catalyst compared both to the same but not fluorinated catalyst and to the reference commercial material (based on the loss of the electrochemical real surface area after accelerated stress tests.

  12. Plasma fluorination of vertically aligned carbon nanotubes: functionalization and thermal stability

    Directory of Open Access Journals (Sweden)

    Claudia Struzzi

    2015-12-01

    Full Text Available Grafting of fluorine species on carbon nanostructures has attracted interest due to the effective modification of physical and chemical properties of the starting materials. Various techniques have been employed to achieve a controlled fluorination yield; however, the effect of contaminants is rarely discussed, although they are often present. In the present work, the fluorination of vertically aligned multiwalled carbon nanotubes was performed using plasma treatment in a magnetron sputtering chamber with fluorine diluted in an argon atmosphere with an Ar/F2 ratio of 95:5. The effect of heavily diluted fluorine in the precursor gas mixture is investigated by evaluating the modifications in the nanotube structure and the electronic properties upon plasma treatment. The existence of oxygen-based grafted species is associated with background oxygen species present in the plasma chamber in addition to fluorine. The thermal stability and desorption process of the fluorine species grafted on the carbon nanotubes during the fluorine plasma treatment were evaluated by combining different spectroscopic techniques.

  13. Controlled radical fluorination of poly(meth)acrylic acids in aqueous solution.

    Science.gov (United States)

    Dong, Yucheng; Wang, Zhentao; Li, Chaozhong

    2017-08-17

    Fluorinated alkenes exhibit very poor reactivity in copolymerization with non-fluorinated polar monomers such as acrylates. Herein we describe a convenient method for the synthesis of poly(vinyl fluoride-co-acrylic acid) and poly(2-fluoropropene-co-methacrylic acid) copolymers. Thus, the silver-catalyzed decarboxylative radical fluorination of poly(acrylic acid) with Selectfluor in water at room temperature affords poly(vinyl fluoride-co-acrylic acid) copolymers in high yields with well-defined molecular weights and polydispersities. A linear correlation is observed between the extent of fluorination and the amount of Selectfluor, indicating that the copolymer of virtually any monomer ratio can be readily accessed by controlling the amount of Selectfluor. This controlled decarboxylative fluorination is extended to poly(methacrylic acid), leading to well-defined poly(2-fluoropropene-co-methacrylic acid) copolymers.Fluorinated alkenes have very poor reactivity in copolymerizations with non-fluorinated polar monomers. Here the authors show silver-catalyzed decarboxylative radical fluorination of poly(acrylic acid) with Selectfluor in water at room temperature to form poly(vinyl fluoride-co-acrylic acid) copolymers.

  14. Electrochemical stability and transformations of fluorinated poly(2,6-dimethyl-1,4-phenylene oxide)

    NARCIS (Netherlands)

    Pud, A.A.; Rogalsky, S.P.; Ghapoval, G.S.; Kharitonov, A.P.; Kemperman, Antonius J.B.

    2000-01-01

    Fluorination of poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) leads to narrowing of its window of electrochemical stability in a cathodic range of potentials. It is found this is connected with appearance of both perfluorinated and incompletely fluorinated units in the polymer. The former units are

  15. Amine salts of nitroazoles

    Science.gov (United States)

    Kienyin Lee; Stinecipher, M.M.

    1993-10-26

    Compositions of matter, a method of providing chemical energy by burning said compositions, and methods of making said compositions are described. These compositions are amine salts of nitroazoles. 1 figure.

  16. What Are Bath Salts?

    Science.gov (United States)

    ... reports of people becoming psychotic (losing touch with reality) and violent. Although it is rare, there have ... in bath salts can produce: feelings of joy increased social interaction increased sex drive paranoia nervousness hallucinations ( ...

  17. Tunable photoluminescence and spectrum split from fluorinated to hydroxylated graphene

    Science.gov (United States)

    Gong, Peiwei; Wang, Jinqing; Sun, Weiming; Wu, Di; Wang, Zhaofeng; Fan, Zengjie; Wang, Honggang; Han, Xiuxun; Yang, Shengrong

    2014-02-01

    Tunable control over the functionalization of graphene is significantly important to manipulate its structure and optoelectronic properties. Yet the chemical inertness of this noble carbon material poses a particular challenge for its decoration without forcing reaction conditions. Here, a mild, operationally simple and controllable protocol is developed to synthesize hydroxylated graphene (HOG) from fluorinated graphene (FG). We successfully demonstrate that under designed alkali environment, fluorine atoms on graphene framework are programmably replaced by hydroxyl groups via a straightforward substitution reaction pathway. Element constituent analyses confirm that homogeneous C-O bonds are successfully grafted on graphene. Rather different from graphene oxide, the photoluminescence (PL) emission spectrum of the obtained HOG becomes split when excited with UV radiation. More interestingly, such transformation from FG facilitates highly tunable PL emission ranging from greenish white (0.343, 0.392) to deep blue (0.156, 0.094). Additionally, both experimental data and density function theory calculation indicate that the chemical functionalization induced structural rearrangement is more important than the chemical decoration itself in tuning the PL emission band tail and splitting energy gaps. This work not only presents a new way to effectively fabricate graphene derivatives with tunable PL performance, but also provides an enlightening insight into the PL origin of graphene related materials.Tunable control over the functionalization of graphene is significantly important to manipulate its structure and optoelectronic properties. Yet the chemical inertness of this noble carbon material poses a particular challenge for its decoration without forcing reaction conditions. Here, a mild, operationally simple and controllable protocol is developed to synthesize hydroxylated graphene (HOG) from fluorinated graphene (FG). We successfully demonstrate that under designed

  18. STUDY OF SILVER CHLORIDE NANOCRYSTALS GROWTH IN FLUORINE PHOSPHATE GLASS

    Directory of Open Access Journals (Sweden)

    M. H. Tong

    2016-07-01

    Full Text Available For the first time, we received and studied the spectral properties of AgCl nanocrystals in fluorine phosphate glass. It was shown that the increase of heat treatment duration leads to the long -wavelength shift of the exciton absorption band and the increase of its intensity. The average size of the AgCl nanocrystals was 2.50 - 3.70 nm. With a decrease in temperature of the glass with AgCl nanocrystals from 25°C to -196°C the shift of the maximum of the exciton absorption towards the short wavelength region took place.

  19. Fluorine-18 NaF PET imaging of child abuse

    Energy Technology Data Exchange (ETDEWEB)

    Drubach, Laura A. [Children' s Hospital Boston and Harvard Medical School, Department of Radiology, Division of Nuclear Medicine/PET, Boston, MA (United States); Sapp, Mark.V. [School of Osteopathic Medicine, Child Abuse Research Education and Services (CARES) Institute University of Medicine and Dentistry of New Jersey, New Jersey (United States); Laffin, Stephen [Children' s Hospital Boston, Department of Radiology, Division of Nuclear Medicine/PET, Boston, MA (United States); Kleinman, Paul K. [Children' s Hospital Boston and Harvard Medical School, Department of Radiology, Division of Musculoskeletal Imaging, Boston, MA (United States)

    2008-07-15

    We describe the use of {sup 18}F-NaF positron emission tomography (PET) whole-body imaging for the evaluation of skeletal trauma in a case of suspected child abuse. To our knowledge, 18F NaF PET has not been used in the past for the evaluation of child abuse. In our patient, this technique detected all sites of trauma shown by initial and follow-up skeletal surveys, including bilateral metaphyseal fractures of the proximal humeri. Fluorine-18 NaF PET has potential advantage over Tc-99m-labeled methylene diphosphonate (MDP) based upon superior image contrast and spatial resolution. (orig.)

  20. Advanced helium regulator for a fluorine propellant system

    Science.gov (United States)

    Wichmann, H.; Yankura, G.

    1976-01-01

    The space storable propulsion module is an advanced high performance (375 seconds Isp minimum) planetary spacecraft propulsion system with a mission life of 5-10 years. The propellants used are liquid fluorine and amine fuel. This application requires high pressure regulator accuracy to optimize propellant depletion characteristics. An advanced regulator concept was prepared which is compatible with both fuel and oxidizer and which features design concepts such as redundant bellows, all-metallic/ceramic construction, friction-free guidance of moving parts and gas damping. Computer simulation of the propulsion module performance over two mission profiles indicated satisfactory minimization of those propellant residual requirements imposed by regulator performance variables.

  1. Atmospheric Gas-Phase Reactions of Fluorinated Compounds and Alkenes

    DEFF Research Database (Denmark)

    Østerstrøm, Freja From

    for Atmospheric Research, Denmark. All setups consist of a chamber and uses UV light to initiate the experiments and Fourier transform infrared spectroscopy for the analysis of the data. The atmospheric chemistry of new chlorofluorocarbon replacements is discussed. Experimental studies have been performed on: (CF......Experimental studies have been performed using three different smog chamber setups to investigate the atmospheric chemistry of fluorinated compounds as well as alkenes. The three instruments were at Ford Motor Company, USA, National Center for Atmospheric Research, USA, and Copenhagen Center...

  2. Tuning the Photoluminescence of Graphene Quantum Dots by Fluorination

    Directory of Open Access Journals (Sweden)

    Yi Luo

    2017-01-01

    Full Text Available Fluorinated graphene quantum dots (F-GQDs were prepared by mixing GQDs and XeF2 in a facile gaseous phase heating method. The F-GQDs with excellent water solubility have a F/C atomic ratio of 84.25% and a diameter of 2–6 nm. The photoluminescence (PL properties of GQDs and F-GQDs were investigated systematically. The results showed that the PL emission of the F-GQDs exhibited an obvious blue-shift of 90 nm compared to that of the GQDs.

  3. Integrated Photonic Devices Incorporating Low-Loss Fluorinated Polymer Materials

    Directory of Open Access Journals (Sweden)

    Hyung-Jong Lee

    2011-06-01

    Full Text Available Low-loss polymer materials incorporating fluorinated compounds have been utilized for the investigation of various functional optical devices useful for optical communication and optical sensor systems. Since reliability issues concerning the polymer device have been resolved, polymeric waveguide devices have been gradually adopted for commercial application systems. The two most successfully commercialized polymeric integrated optic devices, variable optical attenuators and digital optical switches, are reviewed in this paper. Utilizing unique properties of optical polymers which are not available in other optical materials, novel polymeric optical devices are proposed including widely tunable external cavity lasers and integrated optical current sensors.

  4. The Path to Nitrate Salt Disposition

    Energy Technology Data Exchange (ETDEWEB)

    Funk, David John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-03-16

    The topic is presented in a series of slides arranged according to the following outline: LANL nitrate salt incident as thermal runaway (thermally sensitive surrogates, full-scale tests), temperature control for processing, treatment options and down selection, assessment of engineering options, anticipated control set for treatment, and summary of the overall steps for RNS.

  5. In vivo quantification of bone-fluorine by delayed neutron activation analysis: a pilot study of hand-bone-fluorine levels in a Canadian population.

    Science.gov (United States)

    Chamberlain, Mike; Gräfe, James L; Aslam; Byun, Soo-Hyun; Chettle, David R; Egden, Lesley M; Webber, Colin E; McNeill, Fiona E

    2012-03-01

    Humans can be exposed to fluorine (F) through their diet, occupation, environment and oral dental care products. Fluorine, at proper dosages, is believed to have positive effects by reducing the incidence of dental caries, but fluorine toxicity can occur when people are exposed to excessive quantities of fluorine. In this paper we present the results of a small pilot in vivo study on 33 participants living in Southwestern Ontario, Canada. The mean age of participants was 45 ± 18 years with a range of 20-87 years. The observed calcium normalized hand-bone-fluorine concentrations in this small pilot study ranged from 1.1 to 8.8 mg F/g Ca. Every person measured in this study had levels of fluorine in bone above the detection limit of the system. The average fluorine concentration in bone was found to be 3.5 ± 0.4 mg F/g Ca. No difference was observed in average concentration for men and women. In addition, a significant correlation (r(2) = 0.55, p fluorine content and age. The amount of fluorine was found to increase at a rate of 0.084 ± 0.014 mg F/g Ca per year. There was no significant difference observed in this small group of subjects between the accumulation rates in men and women. To the best of our knowledge, this is the first time data from in vivo measurement of fluorine content in humans by neutron activation analysis have been presented. The data determined by this technique were found to be consistent with results from ex vivo studies from other countries. We suggest that the data demonstrate that this low risk non-invasive diagnostic technique will permit the routine assessment of bone-fluorine content with potential application in the study of clinical bone-related diseases. This small study demonstrated that people in Southern Ontario are exposed to fluoride in measureable quantities, and that fluoride can be seen to accumulate in bone with age. However, all volunteers were found to have levels below those expected with clinical fluorosis, and only

  6. A descriptive model of the molten salt reactor experiment after shutdown: Review of FY 1995 progress

    Energy Technology Data Exchange (ETDEWEB)

    Williams, D.F.; Del Cul, G.D.; Toth, L.M.

    1996-01-01

    During FY 1995 considerable progress was made toward gaining a better understanding of the chemistry and transport processes that continue to govern the behavior of the Molten Salt Reactor Experiment (MSRE). As measurements in the MSRE proceed, laboratory studies continue, and better analyses are available, our understanding of the state of the MSRE and the best path toward remediation improves. Because of the immediate concern about the deposit in the auxiliary charcoal bed (ACB), laboratory studies in the past year focused on carbon-fluorine chemistry. Secondary efforts were directed toward investigation of gas generation from MSRE salts by both radiolytic and nonradiolytic pathways. In addition to the laboratory studies, field measurements at the MSRE provided the basis for estimating the inventory of uranium and fluorine in the ACB. Analysis of both temperature and radiation measurements provided independent and consistent estimates of about 2.6 kg of uranium deposited in the top of the ACB. Further analysis efforts included a refinement in the estimates of the fuel- salt source term, the deposited decay energy, and the projected rate of radiolytic gas generation. This report also provides the background material necessary to explain new developments and to review areas of particular interest. The detailed history of the MSRE is extensively documented and is cited where appropriate. This work is also intended to update and complement the more recent MSRE assessment reports.

  7. Molecular beam study of the kinetics of the fluorine--uranium dioxide reaction

    Energy Technology Data Exchange (ETDEWEB)

    Machiels, A.J.

    1976-12-01

    The kinetics of uranium dioxide fluorination were studied using an experimental system in which a molecular beam of fluorine was directed at a heated uranium dioxide single crystal wafer maintained in high vacuum. Gaseous reaction products desorbed from the uranium dioxide were monitored by a quadrupole mass spectrometer with an off-axis electron multiplier. The fluorine beam was modulated; ac phase-lock detection and pulse counting were employed to enhance the signal-to-noise ratio. The uranium dioxide targets were heated from the rear by electron bombardment to a maximum of 1800/sup 0/K. Fluorination of the uranium dioxide was found to produce uranium tetrafluoride in the 900/sup 0/ to 1600/sup 0/K temperature range, confirming the results obtained from thermodynamic considerations (quasi-equilibrium analysis). Fluorination of the uranium dioxide was found to be affected by some process acting as a flywheel smoothing the phase response of the interaction as the modulation frequency was varied.

  8. [Study on the calcium-based sorbent for removal fluorine during coal combustion].

    Science.gov (United States)

    Li, Shu-ling; Qi, Qing-jie; Liu, Jian-zhong; Cao, Xin-yu; Zhou, Jun-hu; Cen, Ke-fa

    2004-03-01

    In the paper, the reaction of CaO-HF and fluorine removal mechanics at high temperature by blending calcium-based sorbents with coal during coal combustion were discussed, and test results about fluorine retention during coal combustion in fluidized bed and chain-grate furnace were reported. The results identified that lime and calcium-based sorbets developed can restratin the emission of fluorine during coal combustion. The efficiency of fluorine removal can reach 66.7%-70.0% at Ca/F 60-70 by blending lime with coal in fluidized bed combustion, and the efficiency of fluorine removal are between 57.32% and 75.19% by blending calcium-based sorbets with coal in chain-grate furnace combustion. Blending CaO or lime with coal during coal combustion can remove SO2 and HF simultaneously.

  9. Exploration of fluorine chemistry at the multidisciplinary interface of chemistry and biology.

    Science.gov (United States)

    Ojima, Iwao

    2013-07-05

    Over the last three decades, my engagement in "fluorine chemistry" has evolved substantially because of the multidisciplinary nature of the research programs. I began my research career as a synthetic chemist in organometallic chemistry and homogeneous catalysis directed toward organic synthesis. Then, I was brought into a very unique world of "fluorine chemistry" in the end of 1970s. I started exploring the interface of fluorine chemistry and transition metal homogeneous catalysis first, which was followed by amino acids, peptides, and peptidomimetics for medicinal chemistry. Since then, I have been exploring the interfaces of fluorine chemistry and multidisciplinary fields of research involving medicinal chemistry, chemical biology, cancer biology, and molecular imaging. This perspective intends to cover my fruitful endeavor in the exploration of fluorine chemistry at the multidisciplinary interface of chemistry and biology in a chronological order to show the evolution of my research interest and strategy.

  10. Effect of fluorination on the surface electrical properties of epoxy resin insulation

    Science.gov (United States)

    Liu, Yaqiang; Li, Liqiang; Du, Xuelian

    2015-02-01

    Epoxy samples were surface fluorinated in a laboratory vessel using a F2/N2 gas mixture to suppress surface charge accumulation. Attenuated total reflection infrared analyses indicate that the fluorination led to substantial variations in chemical composition and structure of the sample surface layer. Measurement results of surface properties indicate that surface conductivity and wettability or polarity were dramatically increased by the fluorination. A very likely decrease in charge trap depth and the adsorbed water on the surface in air are responsible for the high surface conductivity. As a result, charge cannot accumulate on the fluorinated surface even at room temperature, rapidly transporting along the surface. Surface charging current measurements further show a much larger steady state current flowing along the fluorinated surface, suggesting much lower dynamic surface potential or charge density during charging, compared with those for the original surface.

  11. Exploration of Fluorine Chemistry at the Multidisciplinary Interface of Chemistry and Biology

    Science.gov (United States)

    Ojima, Iwao

    2013-01-01

    Over the last three decades, my engagement in “fluorine chemistry” has evolved substantially, because of the multidisciplinary nature of the research programs. I began my research career as a synthetic chemist in organometallic chemistry and homogeneous catalysis directed toward organic synthesis. Then, I was brought into a very unique world of “fluorine chemistry” in the end of 1970s. I started exploring the interface of fluorine chemistry and transition metal homogeneous catalysis first, which was followed by amino acids, peptides, and peptidomimetics for medicinal chemistry. Since then, I have been exploring the interfaces of fluorine chemistry and multidisciplinary fields of research involving medicinal chemistry, chemical biology, cancer biology and molecular imaging. This perspective intends to cover my fruitful endeavor in the exploration of fluorine chemistry at the multidisciplinary interface of chemistry and biology in a chronological order to show the evolution of my research interest and strategy. PMID:23614876

  12. Emergence of Dirac and quantum spin Hall states in fluorinated monolayer As and AsSb

    KAUST Repository

    Zhang, Qingyun

    2016-01-21

    Using first-principles calculations, we investigate the electronic and vibrational properties of monolayer As and AsSb. While the pristine monolayers are semiconductors (direct band gap at the Γ point), fluorination results in Dirac cones at the K points. Fluorinated monolayer As shows a band gap of 0.16 eV due to spin-orbit coupling, and fluorinated monolayer AsSb a larger band gap of 0.37 eV due to inversion symmetry breaking. Spin-orbit coupling induces spin splitting similar to monolayer MoS2. Phonon calculations confirm that both materials are dynamically stable. Calculations of the edge states of nanoribbons by the tight-binding method demonstrate that fluorinated monolayer As is topologically nontrivial in contrast to fluorinated monolayer AsSb.

  13. Iodized Salt Use and Salt Iodine Content among Household Salts from Six Districts of Eastern Nepal.

    Science.gov (United States)

    Khatiwada, S; Gelal, B; Tamang, M K; Kc, R; Singh, S; Lamsal, M; Baral, N

    2014-01-01

    Universal salt iodization is considered the best strategy for controlling iodine deficiency disorders in Nepal. This study was done to find iodized salt use among Nepalese population and the iodine content of household salts. Six districts (Siraha, Saptari, Jhapa, Udayapur, Ilam and Panchthar) were chosen randomly from 16 districts of eastern Nepal for the study. In each district, three schools (private and government) were chosen randomly for sample collection. A total of 1803 salt samples were collected from schools of those districts. For sample collection a clean air tight plastic pouch was provided to each school child and was asked to bring approximately 15 gm of their kitchen salt. The information about type of salt used; 'two child logo' iodized salt or crystal salt was obtained from each child and salt iodine content was estimated using iodometric titration. At the time of study, 85% (n=1533) of Nepalese households were found to use iodized salt whereas 15% (n=270) used crystal salt. The mean iodine content in iodized and crystal salt was 40.8±12.35 ppm and 18.43±11.49 ppm respectively. There was significant difference between iodized and crystal salts use and salt iodine content of iodized and crystal salt among different districts (p value <0.001 at confidence level of 95%). Of the total samples, only 169 samples (9.4% of samples) have iodine content<15 ppm. Most Nepalese households have access to iodized salt most salt samples have sufficient iodine content.

  14. Not salt taste perception but self-reported salt eating habit predicts actual salt intake.

    Science.gov (United States)

    Lee, Hajeong; Cho, Hyun-Jeong; Bae, Eunjin; Kim, Yong Chul; Kim, Suhnggwon; Chin, Ho Jun

    2014-09-01

    Excessive dietary salt intake is related to cardiovascular morbidity and mortality. Although dietary salt restriction is essential, it is difficult to achieve because of salt palatability. However, the association between salt perception or salt eating habit and actual salt intake remains uncertain. In this study, we recruited 74 healthy young individuals. We investigated their salt-eating habits by questionnaire and salt taste threshold through a rating scale that used serial dilution of a sodium chloride solution. Predicted 24-hr urinary salt excretions using Kawasaki's and Tanaka's equations estimated dietary salt intake. Participants' mean age was 35 yr, and 59.5% were male. Salt sense threshold did not show any relationship with actual salt intake and a salt-eating habit. However, those eating "salty" foods showed higher blood pressure (P for trend=0.048) and higher body mass index (BMI; P for trend=0.043). Moreover, a salty eating habit was a significant predictor for actual salt intake (regression coefficient [β] for Kawasaki's equation 1.35, 95% confidence interval [CI] 10-2.69, P=0.048; β for Tanaka's equation 0.66, 95% CI 0.01-1.31, P=0.047). In conclusion, a self-reported salt-eating habit, not salt taste threshold predicts actual salt intake.

  15. Influence of fluorine substitution on the morphology and structure of hydroxyapatite nanocrystals prepared by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Joseph Nathanael, A., E-mail: ajosephnc@yahoo.com [Department of Nanomaterials Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Thin Film and Nanomaterials Laboratory, Department of Physics, Bharathiar University, Coimbatore 641 046 (India); Mangalaraj, D., E-mail: dmraj800@yahoo.com [Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641 046 (India); Hong, S.I., E-mail: sihong@cnu.ac.kr [Thin Film and Nanomaterials Laboratory, Department of Physics, Bharathiar University, Coimbatore 641 046 (India); Masuda, Y. [National Institute of Advanced Industrial Science and Technology (AIST), 2266-98 Anagahora, Shimoshidami, Moriyama-ku, Nagoya 463-8560 (Japan); Rhee, Y.H.; Kim, H.W. [Department of Microbiology, Chungnam National University, Daejeon 305-764 (Korea, Republic of)

    2013-01-15

    Hydroxyapatite (HAp) nanocrystals with different levels of fluorine substitution (P/F = 0, 6, 4 and 2) on the OH sites were produced via hydrothermal method. The fluorine substitution was found to alter the morphology of crystals appreciably. The aspect ratio and the crystallinity of HAp crystals increased with increasing fluorine substitution. The presence of broad ring and hallow ring patterns in electron diffraction suggests the low-crystalline nature of HAp crystals. With increasing fluorine substitution, the diffraction patterns exhibited discrete rings and numerous diffraction spots, implying the increased crystallinity. Raman spectra from the HAp nanoparticles also support the less-crystalline nature of the pristine HAp and the enhanced crystallization by fluorine substitution. In HAp crystals processed with no fluorine substitution, surface energy and planar Ca{sup 2+} density are less sensitive to the crystallographic orientation because of its low-crystalline nature, favoring equi-axed or slightly elongated particles. The addition of fluorine apparently increased the crystallinity, enhancing the orientation dependent growth and accordingly the aspect ratio. Osteoblast proliferation was observed to be enhanced by fluorine substitution in HAp. In vitro biological data support that the excellent osteoblastic cell viability and functional activity of the fluoridated apatite. -- Highlights: Black-Right-Pointing-Pointer Fluorapatite nanorods were produced hydrothermally with different fluorine content. Black-Right-Pointing-Pointer Fluorine substitution was found to alter the morphology of crystals appreciably. Black-Right-Pointing-Pointer It enhances the crystallinity, orientation dependent growth and hence aspect ratio. Black-Right-Pointing-Pointer In vitro cellular analysis shows excellent cell viability of the fluorapatite.

  16. Fabrication of fluorinated polyimide microgrids using magnetically controlled reactive ion etching (MC-RIE) and their applications to an ion drag integrated micropump

    Science.gov (United States)

    Furuya, Akinori; Shimokawa, Fusao; Matsuura, Tohru; Sawada, Renshi

    1996-09-01

    Magnetically controlled reactive ion etching (MC-RIE) of a fluorinated polyimide substrate achieved etching selectivity of up to 2600, resulting in a smoothly etched surface and structures hundreds of micrometers high having good perpendicularity. This technique is useful for three-dimensional microfabrication. As an example of a typical application, we fabricated an ion drag integrated micropump with microgrid sets consisting of 0960-1317/6/3/003/img1 high pole-shaped counter-electrode elements arranged like a pair of interleaved combs by using a fluorinated polyimide as the structural material, metallization, and lift-off using a ZnO sacrificial layer. This micropump moved ethanol with a flow rate of about 0960-1317/6/3/003/img2 when 200 V was applied to the counter electrodes.

  17. Fluorodopa is a Promising Fluorine-19 MRI Probe for Evaluating Striatal Dopaminergic Function in a Rat Model of Parkinson's Disease.

    Science.gov (United States)

    Yanagisawa, Daijiro; Oda, Keisuke; Inden, Masatoshi; Morikawa, Shigehiro; Inubushi, Toshiro; Taniguchi, Takashi; Hijioka, Masanori; Kitamura, Yoshihisa; Tooyama, Ikuo

    2017-07-01

    Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra projecting to the striatum. It has been estimated that approximately 80% of the striatal dopamine and 50% of nigral dopaminergic neurons are lost before the onset of typical motor symptoms, indicating that early diagnosis of PD using noninvasive imaging is feasible. Fluorine-19 (19 F) magnetic resonance imaging (MRI) represents a highly sensitive, easily available, low-background, and cost-effective approach to evaluate dopaminergic function using non-radioactive fluorine-containing dopaminergic agents. The aim of this study was to find a potent 19 F MRI probe to evaluate dopaminergic presynaptic function in the striatum. To select candidates for 19 F MRI probes, we investigated the following eight non-radioactive fluorine-containing dopaminergic agents: fluorodopa (F-DOPA), F-tyrosine, haloperidol, GBR13069 duhydrochloride, GBR12909 duhydrochloride, 3-bis-(4-fluorophenyl) methoxytropane hydrochloride, flupenthixol, and fenfluramine. In 19 F nuclear magnetic resonance measurements, F-tyrosine and F-DOPA displayed a relatively higher signal-to-noise ratio value in brain homogenates than in others. F-DOPA, but not F-tyrosine, induced the rotational behavior in a 6-hydroxydopamine (6-OHDA)-induced hemiparkinsonian rat model. In addition, a significantly high amount of F-DOPA accumulated in the ipsilateral striatum of hemiparkinsonian rats after the injection. We performed 19 F MRI in PC12 cells and isolated rat brain using a 7T MR scanner. Our findings suggest that F-DOPA is a promising 19 F MRI probe for evaluating dopaminergic presynaptic function in the striatum of hemiparkinsonian rats. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  18. WO3 and W Thermal Atomic Layer Etching Using "Conversion-Fluorination" and "Oxidation-Conversion-Fluorination" Mechanisms.

    Science.gov (United States)

    Johnson, Nicholas R; George, Steven M

    2017-10-04

    The thermal atomic layer etching (ALE) of WO3 and W was demonstrated with new "conversion-fluorination" and "oxidation-conversion-fluorination" etching mechanisms. Both of these mechanisms are based on sequential, self-limiting reactions. WO3 ALE was achieved by a "conversion-fluorination" mechanism using an AB exposure sequence with boron trichloride (BCl3) and hydrogen fluoride (HF). BCl3 converts the WO3 surface to a B2O3 layer while forming volatile WOxCly products. Subsequently, HF spontaneously etches the B2O3 layer producing volatile BF3 and H2O products. In situ spectroscopic ellipsometry (SE) studies determined that the BCl3 and HF reactions were self-limiting versus exposure. The WO3 ALE etch rates increased with temperature from 0.55 Å/cycle at 128 °C to 4.19 Å/cycle at 207 °C. W served as an etch stop because BCl3 and HF could not etch the underlying W film. W ALE was performed using a three-step "oxidation-conversion-fluorination" mechanism. In this ABC exposure sequence, the W surface is first oxidized to a WO3 layer using O2/O3. Subsequently, the WO3 layer is etched with BCl3 and HF. SE could simultaneously monitor the W and WO3 thicknesses and conversion of W to WO3. SE measurements showed that the W film thickness decreased linearly with number of ABC reaction cycles. W ALE was shown to be self-limiting with respect to each reaction in the ABC process. The etch rate for W ALE was ∼2.5 Å/cycle at 207 °C. An oxide thickness of ∼20 Å remained after W ALE, but could be removed by sequential BCl3 and HF exposures without affecting the W layer. These new etching mechanisms will enable the thermal ALE of a variety of additional metal materials including those that have volatile metal fluorides.

  19. Effect of Low Salt Diet on Insulin Resistance in Salt Sensitive versus Salt Resistant Hypertension

    Science.gov (United States)

    Garg, Rajesh; Sun, Bei; Williams, Jonathan

    2014-01-01

    Accumulating evidence shows an increase in insulin resistance on salt restriction. We compared the effect of low salt diet on insulin resistance in salt sensitive versus salt resistant hypertensive subjects. We also evaluated the relationship between salt sensitivity of blood pressure and salt sensitivity of insulin resistance in a multivariate regression model. Studies were conducted after one week of high salt (200 mmol/day Na) and one week of low salt (10 mmol/day Na) diet. Salt sensitivity was defined as the fall in systolic blood pressure >15mmHg on low salt diet. The study includes 389 subjects (44% Females, 16% Blacks, BMI 28.5±4.2 Kg/m2). As expected, blood pressure was lower on low salt (129±16/78±9 mmHg) as compared to high salt diet (145±18/86±10 mmHg). Fasting plasma glucose, insulin and HOMA were higher on low salt diet (95.4±19.4 mg/dl, 10.8±7.3 mIU/L and 2.6±1.9) as compared to high salt diet (90.6±10.8 mg/dl, 9.4±5.8 mIU/L and 2.1±1.4) (p salt sensitive (N=193) versus salt resistant (N=196) subjects on either diet. Increase in HOMA on low salt diet was 0.5±1.4 in salt sensitive and 0.4±1.5 in salt resistant subjects (p=NS). On multivariate regression analysis, change in systolic blood pressure was not associated with change in HOMA after including age, BMI, sex, change in serum and urine aldosterone and cortisol into the model. We conclude that the increase in insulin resistance on low salt diet is not affected by salt sensitivity of blood pressure. PMID:25185125

  20. Effects of different fluorination routes on aramid fiber surface structures and interlaminar shear strength of its composites

    Science.gov (United States)

    Gao, Jie; Dai, Yunyang; Wang, Xu; Huang, Jieyang; Yao, Jin; Yang, Jin; Liu, Xiangyang

    2013-04-01

    Poly-p-phenylene-benzimidazole-terephthalamide (PBIA) fiber was surface modified by direct fluorination under three different routes. The fiber was dried under vacuum to remove physisorbed water trapped on it and then fluorinated by the fluorine and oxygen gases or by the fluorine gas only. Results show that the interlaminar shear strength (ILSS) value of these two kinds of fluorinated fiber reinforced epoxy resin was 43.9 MPa and 51.0 MPa, which was improved about 14.0% and 32.5% compared with that of the virgin fiber (38.5 MPa), respectively. In the third route, the fiber was fluorinated by the fluorine and oxygen gases without removing physisorbed water, and the ILSS value decreased for nearly 31.2%, i.e. from 38.5 MPa to 26.5 MPa. X-ray photoelectron spectroscopy (XPS) showed that oxygen-containing and fluorine-containing chemical groups were introduced onto the fiber surface after fluorination, providing a stronger chemical bonding to polymeric matrices. Scanning electronic microscopy (SEM) indicated that the surface morphology of the fluorinated PBIA fiber varied with the different fluorination routes. A mass of compact micro groove structures was formed by the route that the fiber was dried to remove physisorbed water and then fluorinated with fluorine gas only. And these structures would markedly improve the ILSS of the composites. But, a mass of unstable flake surface structures was formed by the route that the fiber was fluorinated with the fluorine and oxygen gases without removing physisorbed water. And these structures would be the weak interface between the fiber and matrix and decrease the ILSS, even a lot of polar chemical groups were bonded onto the fiber surface as well.

  1. Properties of pulsed laser deposited fluorinated hydroxyapatite films on titanium

    Energy Technology Data Exchange (ETDEWEB)

    Rau, J.V., E-mail: giulietta.rau@ism.cnr.it [Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Via del Fosso del Cavaliere 100, 00133 Rome (Italy); Smirnov, V.V. [A.A. Baikov Institute of Metallurgy and Materials Science, Russian Academy of Sciences, Leninsky Prospect 49, 119991 Moscow (Russian Federation); Laureti, S. [Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Via Salaria km 29.300, 00016 Monterotondo Scalo (RM) (Italy); Generosi, A. [Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Via del Fosso del Cavaliere 100, 00133 Rome (Italy); Varvaro, G. [Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Via Salaria km 29.300, 00016 Monterotondo Scalo (RM) (Italy); Fosca, M. [Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Via del Fosso del Cavaliere 100, 00133 Rome (Italy); Ferro, D.; Cesaro, S. Nunziante [Istituto per lo Studio dei Materiali Nanostrutturati, Consiglio Nazionale delle Ricerche, Piazzale Aldo Moro 5, 00185 Rome (Italy); Albertini, V. Rossi [Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Via del Fosso del Cavaliere 100, 00133 Rome (Italy); Barinov, S.M. [A.A. Baikov Institute of Metallurgy and Materials Science, Russian Academy of Sciences, Leninsky Prospect 49, 119991 Moscow (Russian Federation)

    2010-09-15

    Fluorinated hydroxyapatite coated titanium was investigated for application as implant coating for bone substitute materials in orthopaedics and dentistry. Pulsed laser deposition technique was used for films preparation. Fluorinated hydroxyapatite target composition, Ca{sub 10}(PO{sub 4}){sub 6}F{sub 1.37}(OH){sub 0.63}, was maintained at 2 J/cm{sup 2} of laser fluence and 500-600 {sup o}C of the substrate temperature. Prepared films had a compact microstructure, composed of spherical micrometric-size aggregates. The average surface roughness resulted to be of 3 nm for the film grown at 500 {sup o}C and of 10 nm for that grown at 600 {sup o}C, showing that the temperature increase did not favour the growth of a more fine granulated surface. The films were polycrystalline with no preferential growth orientation. The films grown at 500-600 {sup o}C were about 8 {mu}m thick and possessed a hardness of 12-13 GPa. Lower or higher substrate temperature provides the possibility to obtain coatings with different fine texture and roughness, thus tayloring them for various applications.

  2. Palette of fluorinated voltage-sensitive hemicyanine dyes

    Science.gov (United States)

    Yan, Ping; Acker, Corey D.; Zhou, Wen-Liang; Lee, Peter; Bollensdorff, Christian; Negrean, Adrian; Lotti, Jacopo; Sacconi, Leonardo; Antic, Srdjan D.; Kohl, Peter; Mansvelder, Huibert D.; Pavone, Francesco S.; Loew, Leslie M.

    2012-01-01

    Optical recording of membrane potential permits spatially resolved measurement of electrical activity in subcellular regions of single cells, which would be inaccessible to electrodes, and imaging of spatiotemporal patterns of action potential propagation in excitable tissues, such as the brain or heart. However, the available voltage-sensitive dyes (VSDs) are not always spectrally compatible with newly available optical technologies for sensing or manipulating the physiological state of a system. Here, we describe a series of 19 fluorinated VSDs based on the hemicyanine class of chromophores. Strategic placement of the fluorine atoms on the chromophores can result in either blue or red shifts in the absorbance and emission spectra. The range of one-photon excitation wavelengths afforded by these new VSDs spans 440–670 nm; the two-photon excitation range is 900–1,340 nm. The emission of each VSD is shifted by at least 100 nm to the red of its one-photon excitation spectrum. The set of VSDs, thus, affords an extended toolkit for optical recording to match a broad range of experimental requirements. We show the sensitivity to voltage and the photostability of the new VSDs in a series of experimental preparations ranging in scale from single dendritic spines to whole heart. Among the advances shown in these applications are simultaneous recording of voltage and calcium in single dendritic spines and optical electrophysiology recordings using two-photon excitation above 1,100 nm. PMID:23169660

  3. Atomically resolved imaging of highly ordered alternating fluorinated graphene

    Science.gov (United States)

    Kashtiban, Reza J.; Dyson, M. Adam; Nair, Rahul R.; Zan, Recep; Wong, Swee L.; Ramasse, Quentin; Geim, Andre K.; Bangert, Ursel; Sloan, Jeremy

    2014-09-01

    One of the most desirable goals of graphene research is to produce ordered two-dimensional (2D) chemical derivatives of suitable quality for monolayer device fabrication. Here we reveal, by focal series exit wave reconstruction (EWR), that C2F chair is a stable graphene derivative and demonstrates pristine long-range order limited only by the size of a functionalized domain. Focal series of images of graphene and C2F chair formed by reaction with XeF2 were obtained at 80 kV in an aberration-corrected transmission electron microscope. EWR images reveal that single carbon atoms and carbon-fluorine pairs in C2F chair alternate strictly over domain sizes of at least 150 nm2 with electron diffraction indicating ordered domains ≥0.16 μm2. Our results also indicate that, within an ordered domain, functionalization occurs on one side only as theory predicts. In addition, we show that electron diffraction provides a quick and easy method for distinguishing between graphene, C2F chair and fully fluorinated stoichiometric CF 2D phases.

  4. Fluorine and Lithium at the Kimberley Outcrop, Gale Crater

    Science.gov (United States)

    Forni, O.; Vaniman, D. T.; Le Deit, L.; Clegg, S. M.; Lanza, N. L.; Lasue, J.; Bish, D. L.; Mangold, N.; Wiens, R. C.; Meslin, P.-Y.; hide

    2015-01-01

    ChemCam is an active remote sensing instrument which has operated successfully on MSL since landing in August, 2012. Its laser pulses remove dust and to profile through weathering coatings of rocks up to 7 m away. Laser-induced breakdown spectroscopy (LIBS) produces emission spectra of materials ablated from the samples in electronically excited states. As the plasma cools, elements can recombine and molecular emission lines are observed. Recent experiments have shown that some of these molecular emissions can be much brighter than the associated atomic lines, especially when halo-gens and rare earth elements are present. We observed these molecular emissions in some of the ChemCam spectra and report the first detection of chlorine and fluorine with ChemCam. It is also the first time ever that fluorine has been detected on the surface of Mars. Among all the F-bearing observations, one third are observed in the Kimberley outcrop. We will dis-cuss the potential mineralogies related to these observations as well as the related elemental correlations and propose interpretations.

  5. Damage of fluorine-indicator plants in the wild flora

    Energy Technology Data Exchange (ETDEWEB)

    Borsdorf, W.

    1962-01-01

    In an area of middle-Germany, which has an abundance of fluorine-containing exhaust gases, the wild flora and some cultivated plants were examined in order to find out about their availability as an indicator for the extent and intensity of damages of fluorine. As a result of three years of observation, a list of 59 kinds was found, whereby 4 sensitivity-groups were determined based on the macroscopic damage (necroses of the edges and the rim of the leaves, less frequently in the intercostal fields). Vitis vinifera L., Carpinus betulus L., Iris germanic L., Arrhenatherum elatium L., J. and C. Presl and Dactylis glomerata L. proved to be highly sensitive. Generally the kinds of gramiceea and Polygonacea seem to be sensitive, those of the Liabiates, composites papilionacea crucifers, and Umbelifera on the other hand seem to be very resistant. The amount of damage is influenced among other things by a number of environmental factors (formation of the terrain, main directions of the wind, precipitations, degree of wooded area).

  6. Production of High Value Fluorine Gases for the Semiconductor Industry

    Energy Technology Data Exchange (ETDEWEB)

    Bulko, J. B.

    2003-10-23

    The chemistry to manufacture high purity GeF{sub 4} and WF{sub 6} for use in the semiconductor industry using Starmet's new fluorine extraction technology has been developed. Production of GeF{sub 4} was established using a tube-style reactor system where conversion yields as high as 98.1% were attained for the reaction between and GeO{sub 2}. Collection of the fluoride gas improved to 97.7% when the reactor sweep gas contained a small fraction of dry air (10-12 vol%) along with helium. The lab-synthesized product was shown to contain the least amount of infrared active and elemental impurities when compared with a reference material certified at 99.99% purity. Analysis of the ''as-produced'' gas using ICP-MS showed that uranium could not be detected at a detection limit of 0.019ppm-wt. A process to make WF{sub 6} from WO{sub 2}, and UF{sub 4}, produced a WOF{sub 4} intermediate, which proved difficult to convert to tungsten hexafluoride using titanium fluoride as a fluorinating agent.

  7. Enhanced Light Absorption in Fluorinated Ternary Small-Molecule Photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Eastham, Nicholas D. [Department; Dudnik, Alexander S. [Department; Harutyunyan, Boris [Department; Aldrich, Thomas J. [Department; Leonardi, Matthew J. [Department; Manley, Eric F. [Department; Chemical; Butler, Melanie R. [Department; Harschneck, Tobias [Department; Ratner, Mark A. [Department; Chen, Lin X. [Department; Chemical; Bedzyk, Michael J. [Department; Department; Melkonyan, Ferdinand S. [Department; Facchetti, Antonio [Department; Chang, Robert P. H. [Department; Marks, Tobin J. [Department; Department

    2017-06-14

    Using small-molecule donor (SMD) semiconductors in organic photovoltaics (OPVs) has historically afforded lower power conversion efficiencies (PCEs) than their polymeric counterparts. The PCE difference is attributed to shorter conjugated backbones, resulting in reduced intermolecular interactions. Here, a new pair of SMDs is synthesized based on the diketopyrrolopyrrole-benzodithiophene-diketopyrrolopyrrole (BDT-DPP2) skeleton but having fluorinated and fluorinefree aromatic side-chain substituents. Ternary OPVs having varied ratios of the two SMDs with PC61BM as the acceptor exhibit tunable open-circuit voltages (Vocs) between 0.833 and 0.944 V due to a fluorination-induced shift in energy levels and the electronic “alloy” formed from the miscibility of the two SMDs. A 15% increase in PCE is observed at the optimal ternary SMD ratio, with the short-circuit current density (Jsc) significantly increased to 9.18 mA/cm2. The origin of Jsc enhancement is analyzed via charge generation, transport, and diffuse reflectance measurements, and is attributed to increased optical absorption arising from a maximum in film crystallinity at this SMD ratio, observed by grazing incidence wide-angle X-ray scattering.

  8. Detection of Corrosion Resistance of Components in Cyclic Salt Spray

    Directory of Open Access Journals (Sweden)

    Štefan Álló

    2015-01-01

    Full Text Available The aim of this research is, to investigate the influence of two types of cyclic salt spray tests on parts surface treated with galvanizing. On the selected components was performed the method Zn-Ni surface treating on the bath line. Subsequently were the components embedded in the corrosion chamber, where was performed two types of cyclic salt test. In the first test was performed 4 hour salt spray, 8 hours drying, 60 hours condensation and 24 hours drying. Once cycle lasted 96 hours, and it was repeated 4 times. During the second test was performed 2 hours salt spray, 2 hours condensation. The cycle was repeated 4 times, that means 96 hours. After the cycle was performed 72 hours free relaxation in the corrosion chamber, on 20–25 °C temperature. As the research showed, after the cyclic salt spray was no red corrosion on the selected components. The white corrosion appeared only slightly.

  9. Great Salt Lake, Utah

    Science.gov (United States)

    Stephens, Doyle W.; Gardner, Joe F.

    1999-01-01

    This document is intended as a source of general information and facts about Great Salt Lake, Utah. This U.S. Geological Survey information sheet answers frequently asked questions about Great Salt Lake. Topics include: History, salinity, brine shrimp, brine flies, migratory birds, and recreation. Great Salt Lake, the shrunken remnant of prehistoric Lake Bonneville, has no outlet. Dissolved salts accumulate in the lake by evaporation. Salinity south of the causeway has ranged from 6 percent to 27 percent over a period of 22 years (2 to 7 times saltier than the ocean). The high salinity supports a mineral industry that extracts about 2 million tons of salt from the lake each year. The aquatic ecosystem consists of more than 30 species of organisms. Harvest of its best-known species, the brine shrimp, annually supplies millions of pounds of food for the aquaculture industry worldwide. The lake is used extensively by millions of migratory and nesting birds and is a place of solitude for people. All this occurs in a lake that is located at the bottom of a 35,000-square-mile drainage basin that has a human population of more than 1.5 million.

  10. Functionalization of nanomaterials with aryldiazonium salts.

    Science.gov (United States)

    Mohamed, Ahmed A; Salmi, Zakaria; Dahoumane, Si Amar; Mekki, Ahmed; Carbonnier, Benjamin; Chehimi, Mohamed M

    2015-11-01

    This paper reviews the surface modification strategies of a wide range of nanomaterials using aryldiazonium salts. After a brief history of diazonium salts since their discovery by Peter Griess in 1858, we will tackle the surface chemistry using these compounds since the first trials in the 1950s. We will then focus on the modern surface chemistry of aryldiazonium salts for the modification of materials, particularly metallic, semiconductors, metal oxide nanoparticles, carbon-based nanostructures, diamond and clays. The successful modification of sp(2) carbon materials and metals by aryldiazonium salts paved the way to innovative strategies for the attachment of aryl layers to metal oxide nanoparticles and nanodiamonds, and intercalation of clays. Interestingly, diazotized surfaces can easily trap nanoparticles and nanotubes while diazotized nanoparticles can be (electro)chemically reduced on electrode/materials surfaces as molecular compounds. Both strategies provided organized 2D surface assembled nanoparticles. In this review, aryldiazonium salts are highlighted as efficient coupling agents for many types of molecular, macromolecular and nanoparticulate species, therefore ensuring stability to colloids on the one hand, and the construction of composite materials and hybrid systems with robust and durable interfaces/interphases, on the other hand. The last section is dedicated to a selection of patents and industrial products based on aryldiazonium-modified nanomaterials. After nearly 160 years of organic chemistry, diazonium salts have entered a new, long and thriving era for the benefit of materials, colloids, and surface scientists. This tempts us to introduce the terminology of "diazonics" we define as the science and technology of aryldiazonium salt-derived materials. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Thermal and oxidation stability of organo-fluorine compound-mixed electrolyte solutions for lithium ion batteries

    Science.gov (United States)

    Nishikawa, Daiki; Nakajima, Tsuyoshi; Ohzawa, Yoshimi; Koh, Meiten; Yamauchi, Akiyoshi; Kagawa, Michiru; Aoyama, Hirokazu

    2013-12-01

    Thermal and oxidation stability of fluorine compound-mixed electrolyte solutions have been investigated. Charge/discharge behavior of natural graphite electrode has been also examined in the same electrolyte solutions. Fluorine compounds demonstrate much lower reactivity with metallic Li than ethylene carbonate/dimethyl carbonate. Fluorine compound-mixed electrolyte solutions show the lower reactivity with LiC6 and the smaller exothermic peaks due to decomposition of electrolyte solutions and surface films than original solutions without fluorine compound. Oxidation currents are also smaller in fluorine compound-mixed electrolyte solutions than in original ones. First coulombic efficiencies in fluorine compound-mixed electrolyte solutions are similar to those in original ethylene carbonate-based solutions except one case. Mixing of fluorine compounds highly increase first coulombic efficiencies of natural graphite electrode in propylene carbonate-containing solution.

  12. Clinical perspectives of hybrid proton-fluorine magnetic resonance imaging and spectroscopy.

    Science.gov (United States)

    Wolters, Martijn; Mohades, Seyede G; Hackeng, Tilman M; Post, Mark J; Kooi, Marianne E; Backes, Walter H

    2013-05-01

    The number of applications of fluorine 19 (19F) magnetic resonance (MR) imaging and spectroscopy in biomedical and clinical research is steadily growing. The 100% natural abundance of fluorine and its relatively high sensitivity for MR (83% to that of protons) make it an interesting nucleus for a wide range of MR applications. Fluorinated contrast media have a number of advantages over the conventionally used gadolinium-based or iron-based contrast agents. The absence of an endogenous fluorine background intensity in the human body facilitates reliable quantification of fluorinated contrast medium or drugs. Anatomy can be visualized separately with proton MR imaging, creating the application of hybrid hydrogen 1 (1H)/19F MR imaging. The availability of 2 channels (ie, the 1H and 19F channels) enables dual-targeted molecular imaging. Recently, novel developments have emerged on fluorine-based contrast media in preclinical studies and imaging techniques. The developments in fluorine MR seem promising for clinical applications, with contributions in therapy monitoring, assessment of lung function, angiography, and molecular imaging. This review outlines the translation from recent advances in preclinical MR imaging and spectroscopy to future perspectives of clinical hybrid 1H/19/F MR imaging applications.

  13. Design and Operating Criteria for Fluorine Disposal by Reaction with Charcoal

    Science.gov (United States)

    Schmidt, Harold W.

    1959-01-01

    Experiments with the charcoal-fluorine reaction for the disposal of fluorine have shown generally that this method is effective over a wide range of conditions. Pure fluorine or fluorine diluted with nitrogen to concentrations as low as 0.3 percent fluorine may be disposed of efficiently within the rate limitation. Maximum feed rates have been established and are inversely proportional to the charcoal-bed particle diameter. Moisture content in the charcoal had no appreciable effect on the disposal efficiency after the reaction zone was established and the moisture was driven off by the heat of reaction. There was no evidence of bed poisoning resulting from continued use. Design parameters may be based on the stoichiometric requirements plus sufficient excess charcoal to maintain desired efficiency toward the end of a disposal operation. The length of time a given reactor may be used continuously is limited by the rate of fluorine input and the resistance of the system to heat and fluorine attack. Refractory-lined reactors have been in routine field use at the Lewis Research Center for over a year and have given satisfactory service over a wide range of conditions.

  14. Fluorine determination in human healthy and carious teeth using the PIGE technique

    Science.gov (United States)

    Carvalho, M. L.; Karydas, A. G.; Casaca, C.; Zarkadas, Ch; Paradellis, Th; Kokkoris, M.; Nsouli, B.; Cunha, A. S.

    2001-09-01

    The purpose of this study is to determine and compare the fluorine concentration in human teeth from two different populations, living in the Portuguese quite isolated islands of Açores: S. Miguel and Terceira. Both populations have similar dietary habits, similar occupational activities, mostly rural, and the age of both populations is more or less the same, around 40 years. No chronic diseases were registered in any of the donors. The two groups are exposed to different levels of fluorine in drinking water. Terceira island has moderate fluorine concentration levels (1-2 μg g -1) while S. Miguel island is known for the high fluorine concentration levels in its water (>3 μg g -1), especially in one area known as Furnas. Thirty-three teeth, 17 healthy and 16 carious without restoration (14 incisors and canines, 7 premolars and 12 molars), were collected and analyzed for the determination of fluorine concentration in the dentine region, using the nuclear reaction 19F( p, αγ) 16O. The teeth were cross-sectioned along the vertical plane and polished, in order to obtain a smooth and plane surface of about 1 mm thickness. In this work an association between caries prevalence and fluorine content of drinking water is discussed and the variation of fluorine concentration among different types of teeth (canines and incisors, premolars, molars) and physical state (carious and non-carious) is examined.

  15. Targeted fluorination of a nonsteroidal anti-inflammatory drug to prolong metabolic half-life.

    Science.gov (United States)

    Shaughnessy, Maxwell J; Harsanyi, Antal; Li, Jingji; Bright, Tara; Murphy, Cormac D; Sandford, Graham

    2014-04-01

    In drug design, one way of improving metabolic stability is to introduce fluorine at a metabolically labile site. In the early stages of drug design, identification of such sites is challenging, and a rapid method of assessing the effect of fluorination on a putative drug's metabolic stability would be of clear benefit. One approach to this is to employ micro-organisms that are established as models of drug metabolism in parallel with the synthesis of fluorinated drug analogues. In this study, we have used the filamentous fungus Cunninghamella elegans to identify the metabolically labile site of the nonsteroidal anti-inflammatory drug flurbiprofen, to aid in the design of fluorinated derivatives that were subsequently synthesised. The effect of the additional fluorine substitution on cytochrome P450-catalysed oxidation was then determined via incubation with the fungus, and demonstrated that fluorine substitution at the 4'-position rendered the drug inactive to oxidative transformation, whereas substitution of fluorine at either 2' or 3' resulted in slower oxidation compared to the original drug. This approach to modulating the metabolic stability of a drug-like compound is widely applicable and can be used to address metabolic issues of otherwise good lead compounds in drug development. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Mineral resource of the month: salt

    Science.gov (United States)

    Kostick, Dennis S.

    2010-01-01

    The article presents information on various types of salt. Rock salt is either found from underground halite deposits or near the surface. Other types of salt include solar salt, salt brine, and vacuum pan salt. The different uses of salt are also given including its use as a flavor enhancer, as a road deicing agent, and to manufacture sodium hydroxide.

  17. Gas releases from salt

    Energy Technology Data Exchange (ETDEWEB)

    Ehgartner, B.; Neal, J.; Hinkebein, T.

    1998-06-01

    The occurrence of gas in salt mines and caverns has presented some serious problems to facility operators. Salt mines have long experienced sudden, usually unexpected expulsions of gas and salt from a production face, commonly known as outbursts. Outbursts can release over one million cubic feet of methane and fractured salt, and are responsible for the lives of numerous miners and explosions. Equipment, production time, and even entire mines have been lost due to outbursts. An outburst creates a cornucopian shaped hole that can reach heights of several hundred feet. The potential occurrence of outbursts must be factored into mine design and mining methods. In caverns, the occurrence of outbursts and steady infiltration of gas into stored product can effect the quality of the product, particularly over the long-term, and in some cases renders the product unusable as is or difficult to transport. Gas has also been known to collect in the roof traps of caverns resulting in safety and operational concerns. The intent of this paper is to summarize the existing knowledge on gas releases from salt. The compiled information can provide a better understanding of the phenomena and gain insight into the causative mechanisms that, once established, can help mitigate the variety of problems associated with gas releases from salt. Outbursts, as documented in mines, are discussed first. This is followed by a discussion of the relatively slow gas infiltration into stored crude oil, as observed and modeled in the caverns of the US Strategic Petroleum Reserve. A model that predicts outburst pressure kicks in caverns is also discussed.

  18. Synthesis of polymeric fluorinated sol–gel precursor for fabrication of superhydrophobic coating

    Energy Technology Data Exchange (ETDEWEB)

    Li, Qianqian; Yan, Yuheng; Yu, Miao; Song, Botao; Shi, Suqing, E-mail: shisq@nwu.edu.cn; Gong, Yongkuan

    2016-03-30

    Graphical abstract: - Highlights: • A polymeric fluorinated sol–gel precursor PFT is designed to fabricate superhydrophobic coatings. • The superhydrophobicity could be governed by the concentration of PFT. • Bio-mimicking self-cleaning property similar to lotus leaves could also be achieved. - Abstract: A fluorinated polymeric sol–gel precursor (PFT) is synthesized by copolymerization of 2,3,4,5,5,5-hexafluoro-2,4-bis(trifluorinated methyl)pentyl methacrylate (FMA) and 3-methacryloxypropyltrimethoxysilane (TSMA) to replace the expensive long chain fluorinated alkylsilanes. The fluorinated silica sol is prepared by introducing PFT as co-precursor of tetraethyl orthosilicate (TEOS) in the sol–gel process with ammonium hydroxide as catalyst, which is then used to fabricate superhydrophobic coating on glass substrate through a simple dip-coating method. The effects of PFT concentrations on the chemical structure of the formed fluorinated silica, the surface chemical composition, surface morphology, wetting and self-cleaning properties of the resultant fluorinated silica coatings were studied by using X-ray powder diffraction (XRD), Fourier transform infrared spectrometer (FTIR), X-ray photoelectron spectrophotometer (XPS), scanning electron microscopy (SEM) and water contact angle measurements (WCA). The results show that the fluorinated silica sols are successfully obtained. The size and size distribution of the fluorinated silica particles are found greatly dependent on the concentration of PFT, which play a crucial role in the surface morphology of the corresponding fluorinated silica coatings. The suitable PFT concentration added in the sol–gel stage, i.e. for F-sol-1 and F-sol-2, is helpful to achieve both the low surface energy and multi-scaled microstructures, leading to the formation of the superhydrophobic coatings with bio-mimicking self-cleaning property similar to lotus leaves.

  19. Mechanism for salt scaling

    Science.gov (United States)

    Valenza, John J., II

    Salt scaling is superficial damage caused by freezing a saline solution on the surface of a cementitious body. The damage consists of the removal of small chips or flakes of binder. The discovery of this phenomenon in the early 1950's prompted hundreds of experimental studies, which clearly elucidated the characteristics of this damage. In particular it was shown that a pessimum salt concentration exists, where a moderate salt concentration (˜3%) results in the most damage. Despite the numerous studies, the mechanism responsible for salt scaling has not been identified. In this work it is shown that salt scaling is a result of the large thermal expansion mismatch between ice and the cementitious body, and that the mechanism responsible for damage is analogous to glue-spalling. When ice forms on a cementitious body a bi-material composite is formed. The thermal expansion coefficient of the ice is ˜5 times that of the underlying body, so when the temperature of the composite is lowered below the melting point, the ice goes into tension. Once this stress exceeds the strength of the ice, cracks initiate in the ice and propagate into the surface of the cementitious body, removing a flake of material. The glue-spall mechanism accounts for all of the characteristics of salt scaling. In particular, a theoretical analysis is presented which shows that the pessimum concentration is a consequence of the effect of brine pockets on the mechanical properties of ice, and that the damage morphology is accounted for by fracture mechanics. Finally, empirical evidence is presented that proves that the glue-small mechanism is the primary cause of salt scaling. The primary experimental tool used in this study is a novel warping experiment, where a pool of liquid is formed on top of a thin (˜3 mm) plate of cement paste. Stresses in the plate, including thermal expansion mismatch, result in warping of the plate, which is easily detected. This technique revealed the existence of

  20. Iron(III) Fluorinated Porphyrins: Greener Chemistry from Synthesis to Oxidative Catalysis Reactions.

    Science.gov (United States)

    Rebelo, Susana L H; Silva, André M N; Medforth, Craig J; Freire, Cristina

    2016-04-12

    Iron(III) fluorinated porphyrins play a central role in the biomimetics of heme enzymes and enable cleaner routes to the oxidation of organic compounds. The present work reports significant improvements in the eco-compatibility of the synthesis of 5,10,15,20-tetrakis-pentafluorophenylporphyrin (H₂TPFPP) and the corresponding iron complex [Fe(TPFPP)Cl], and the use of [Fe(TPFPP)Cl] as an oxidation catalyst in green conditions. The preparations of H₂TPFPP and [Fe(TPFPP)Cl] typically use toxic solvents and can be made significantly greener and simpler using microwave heating and optimization of the reaction conditions. In the optimized procedure it was possible to eliminate nitrobenzene from the porphyrin synthesis and replace DMF by acetonitrile in the metalation reaction, concomitant with a significant reduction of reaction time and simplification of the purification procedure. The Fe(III)porphyrin is then tested as catalyst in the selective oxidation of aromatics at room temperature using a green oxidant (hydrogen peroxide) and green solvent (ethanol). Efficient epoxidation of indene and selective oxidation of 3,5-dimethylphenol and naphthalene to the corresponding quinones is observed.

  1. Iron(III Fluorinated Porphyrins: Greener Chemistry from Synthesis to Oxidative Catalysis Reactions

    Directory of Open Access Journals (Sweden)

    Susana L. H. Rebelo

    2016-04-01

    Full Text Available Iron(III fluorinated porphyrins play a central role in the biomimetics of heme enzymes and enable cleaner routes to the oxidation of organic compounds. The present work reports significant improvements in the eco-compatibility of the synthesis of 5,10,15,20-tetrakis-pentafluorophenylporphyrin (H2TPFPP and the corresponding iron complex [Fe(TPFPPCl], and the use of [Fe(TPFPPCl] as an oxidation catalyst in green conditions. The preparations of H2TPFPP and [Fe(TPFPPCl] typically use toxic solvents and can be made significantly greener and simpler using microwave heating and optimization of the reaction conditions. In the optimized procedure it was possible to eliminate nitrobenzene from the porphyrin synthesis and replace DMF by acetonitrile in the metalation reaction, concomitant with a significant reduction of reaction time and simplification of the purification procedure. The Fe(IIIporphyrin is then tested as catalyst in the selective oxidation of aromatics at room temperature using a green oxidant (hydrogen peroxide and green solvent (ethanol. Efficient epoxidation of indene and selective oxidation of 3,5-dimethylphenol and naphthalene to the corresponding quinones is observed.

  2. Oxygen sparging of residue salts

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, E.; Griego, W.J.; Owens, S.D.; Thorn, C.W.; Vigil, R.A.

    1993-03-01

    Oxygen sparge is a process for treating salt residues at Los Alamos National Laboratory by sparging oxygen through molten salts. Oxygen reacts with the plutonium trichloride in these salts to form plutonium dioxide. There is further reaction of the plutonium dioxide with plutonium metal and the molten salt to form plutonium oxychloride. Both of the oxide plutonium species are insoluble in the salt and collect atthe bottom of the crucible. This results in a decrease of a factor of 2--3 in the amount of salt that must be treated, and the amount of waste generated by aqueous treatment methods.

  3. Diversity and Evolution of Salt Tolerance in the Genus Vigna.

    Directory of Open Access Journals (Sweden)

    Kohtaro Iseki

    Full Text Available Breeding salt tolerant plants is difficult without utilizing a diversity of wild crop relatives. Since the genus Vigna (family Fabaceae is comprised of many wild relatives adapted to various environmental conditions, we evaluated the salt tolerance of 69 accessions of this genus, including that of wild and domesticated accessions originating from Asia, Africa, Oceania, and South America. We grew plants under 50 mM and 200 mM NaCl for two weeks and then measured the biomass, relative quantum yield of photosystem II, leaf Na+ concentrations, and leaf K+ concentrations. The accessions were clustered into four groups: the most tolerant, tolerant, moderately susceptible, and susceptible. From the most tolerant group, we selected six accessions, all of which were wild accessions adapted to coastal environments, as promising sources of salt tolerance because of their consistently high relative shoot biomass and relative quantum yield. Interestingly, variations in leaf Na+ concentration were observed between the accessions in the most tolerant group, suggesting different mechanisms were responsible for their salt tolerance. Phylogenetic analysis with nuclear DNA sequences revealed that salt tolerance had evolved independently at least four times in the genus Vigna, within a relatively short period. The findings suggested that simple genetic changes in a few genes might have greatly affected salt tolerances. The elucidation of genetic mechanisms of salt tolerances in the selected accessions may contribute to improving the poor salt tolerance in legume crops.

  4. Exploring the effect of fluorinated anions on the CO2/N2 separation of supported ionic liquid membranes.

    Science.gov (United States)

    Gouveia, Andreia S L; Tomé, Liliana C; Lozinskaya, Elena I; Shaplov, Alexander S; Vygodskii, Yakov S; Marrucho, Isabel M

    2017-11-01

    The CO2 and N2 permeation properties of ionic liquids (ILs) based on the 1-ethyl-3-methylimidazolium cation ([C2mim](+)) and different fluorinated anions, namely 2,2,2-trifluoromethylsulfonyl-N-cyanoamide ([TFSAM](-)), bis(fluorosulfonyl) imide ([FSI](-)), nonafluorobutanesulfonate ([C4F9SO3](-)), tris(pentafluoroethyl)trifluorophosphate ([FAP](-)), and bis(pentafluoroethylsulfonyl)imide ([BETI](-)) anions, were measured using supported ionic liquid membranes (SILMs). The results show that pure ILs containing [TFSAM](-) and [FSI](-) anions present the highest CO2 permeabilities, 753 and 843 Barrer, as well as the greatest CO2/N2 permselectivities of 43.9 and 46.1, respectively, with CO2/N2 separation performances on top of or above the Robeson 2008 upper bound. The re-design of the [TFSAM](-) anion by structural unfolding was investigated through the use of IL mixtures. The gas transport and CO2/N2 separation properties through a pure [C2mim][TFSAM] SILM are compared to those of two different binary IL mixtures containing fluorinated and cyano-functionalized groups in the anions. Although the use of IL mixtures is a promising strategy to tailor gas permeation through SILMs, the pure [C2mim][TFSAM] SILM displays higher CO2 permeability, diffusivity and solubility than the selected IL mixtures. Nevertheless, both the prepared mixtures present CO2 separation performances that are on top of or above the Robeson plot.

  5. On the Effect of Fluorination of 2,1,3-Benzothiadiazole

    KAUST Repository

    Nielsen, Christian B.

    2015-04-22

    The 4,7-dithieno-2,1,3-benzothiadiazole (DTBT) moiety and its fluorinated counterpart are important pi-conjugated building blocks in the field of organic electronics. Here we present a combined experimental and theoretical investigation into fundamental properties relating to these two molecular entities and discuss the potential impact on extended π-conjugated materials and their electronic properties. While the fluorinated derivative, in the solid state, packs with a smaller co-facial overlap than DTBT, we report experimental evidence for stronger optical absorption as well as stronger intra- and intermolecular contacts upon fluorination.

  6. [Development of novel methods for synthesis of heterocyclic compounds catalyzed by transition metals in fluorinated alcohols].

    Science.gov (United States)

    Saito, Akio

    2008-08-01

    New possibilities for catalytic syntheses of lactone derivatives and nitrogen-containing heterocyclic compounds in fluorinated alcohols are described. The cationic Rh(I) catalyst in fluorinated alcohol solvents (hexafluoroisopropanol: HFIP, trifluoroethanol: TFE) brought about not only mild cycloaddition reactions of ester-tethered compounds but also a facile formation of indole derivatives by the aromatic amino-Claisen rearrangement of N-propargyl aniline derivatives. The use of HFIP as an additive exerted a remarkable effect on the Pictet-Spengler reaction catalyzed by the fluorinated surfactant-combined Brønsted acid catalyst in water.

  7. Synthesis and ATRP of novel fluorinated aromatic monomer with pendant sulfonate group

    DEFF Research Database (Denmark)

    Dimitrov, Ivaylo; Jankova Atanasova, Katja; Hvilsted, Søren

    2013-01-01

    Novel, fluorinated monomer with pendant sulfonate group was synthesized utilizing a two-step derivatization of 2,3,4,5,6-pentafluorostyrene (FS). The first step was a nucleophilic substitution of the fluorine atom in para position by hydroxyl group followed by sulfopropylation. The monomer...... was polymerized under aqueous ATRP conditions to yield phenyl-fluorinated aromatic homopolymer bearing pendant sulfonates on each repeating unit. Furthermore, this polymer was used as macroinitiator for the ATRP of poly(ethylene glycol) methacrylate. The polymers were characterized by 1H NMR, SEC and FTIR...

  8. High Stability Performance of Superhydrophobic Modified Fluorinated Graphene Films on Copper Alloy Substrates

    Directory of Open Access Journals (Sweden)

    Rafik Abbas

    2017-01-01

    Full Text Available A stable self-cleaning superhydrophobic modified fluorinated graphene surface with micro/nanostructure was successfully fabricated on copper substrates via drop coating process. Irregularly stacked island-like multilayered fluorinated graphene nanoflakes comprised the microstructure. The fabricated films exhibited outstanding superhydrophobic property with a water contact angle 167° and water sliding angle lower than 4°. The developed superhydrophobic surface showed excellent corrosion resistance with insignificant decrease of water contact angle 166° in 3.5 wt.% NaCl solution. This stable highly hydrophobic performance of the fluorinated graphene films could be useful in self-cleaning, antifogging, corrosion resistive coatings and microfluidic devices.

  9. Two-photon-excited fluorescence spectroscopy of atomic fluorine at 170 nm

    Science.gov (United States)

    Herring, G. C.; Dyer, Mark J.; Jusinski, Leonard E.; Bischel, William K.

    1988-01-01

    Two-photon-excited fluorescence spectroscopy of atomic fluorine is reported. A doubled dye laser at 286-nm is Raman shifted in H2 to 170 nm (sixth anti-Stokes order) to excite ground-state 2P(0)J fluorine atoms to the 2D(0)J level. The fluorine atoms are detected by one of two methods: observing the fluorescence decay to the 2PJ level or observing F(+) production through the absorption of an additional photon by the excited atoms. Relative two-photon absorption cross sections to and the radiative lifetimes of the 2D(0)J states are measured.

  10. Fluorinated compounds in medicinal chemistry: recent applications, synthetic advances and matched-pair analyses.

    Science.gov (United States)

    Barnes-Seeman, David; Beck, Jeremy; Springer, Clayton

    2014-01-01

    In recent years, several new fluorinated functional groups have been employed in medicinal chemistry. This review will highlight some recent developments in this area. We draw attention to useful synthetic advances for the installation of fluorine-containing groups. In addition, we examine the application of some fluorinated functional groups that have recently been gaining popularity in drug discovery. We use matched-pair analysis to assemble aggregate data on the impact on potency of one of these groups, pentafluorosulfanyl, as compared to trifluoromethyl. We further used matchedpair analysis to identify some interesting effects on in vitro ADME properties of replacing H by F on certain moieties.

  11. Chemical aminoacylation of tRNAs with fluorinated amino acids for in vitro protein mutagenesis

    Directory of Open Access Journals (Sweden)

    Shijie Ye

    2010-04-01

    Full Text Available This article describes the chemical aminoacylation of the yeast phenylalanine suppressor tRNA with a series of amino acids bearing fluorinated side chains via the hybrid dinucleotide pdCpA and ligation to the corresponding truncated tRNA species. Aminoacyl-tRNAs can be used to synthesize biologically relevant proteins which contain fluorinated amino acids at specific sites by means of a cell-free translation system. Such engineered proteins are expected to contribute to our understanding of discrete fluorines’ interaction with canonical amino acids in a native protein environment and to enable the design of fluorinated proteins with arbitrary desired properties.

  12. Enabling LiTFSI-based electrolytes for safer lithium-ion batteries by using linear fluorinated carbonates as (Co)solvent.

    Science.gov (United States)

    Kalhoff, Julian; Bresser, Dominic; Bolloli, Marco; Alloin, Fannie; Sanchez, Jean-Yves; Passerini, Stefano

    2014-10-01

    In this Full Paper we show that the use of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) as conducting salt in commercial lithium-ion batteries is made possible by introducing fluorinated linear carbonates as electrolyte (co)solvents. Electrolyte compositions based on LiTFSI and fluorinated carbonates were characterized regarding their ionic conductivity and electrochemical stability towards oxidation and with respect to their ability to form a protective film of aluminum fluoride on the aluminum surface. Moreover, the investigation of the electrochemical performance of standard lithium-ion anodes (graphite) and cathodes (Li[Ni1/3 Mn1/3 Co1/3 ]O2 , NMC) in half-cell configuration showed stable cycle life and good rate capability. Finally, an NMC/graphite full-cell confirmed the suitability of such electrolyte compositions for practical lithium-ion cells, thus enabling the complete replacement of LiPF6 and allowing the realization of substantially safer lithium-ion batteries. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. A Fine-Tuned Fluorinated MOF Addresses the Needs for Trace CO2 Removal and Air Capture Using Physisorption.

    Science.gov (United States)

    Bhatt, Prashant M; Belmabkhout, Youssef; Cadiau, Amandine; Adil, Karim; Shekhah, Osama; Shkurenko, Aleksander; Barbour, Leonard J; Eddaoudi, Mohamed

    2016-07-27

    The development of functional solid-state materials for carbon capture at low carbon dioxide (CO2) concentrations, namely, from confined spaces (MOF), NbOFFIVE-1-Ni, with the appropriate pore system (size, shape, and functionality), ideal for the effective and energy-efficient removal of trace carbon dioxide. Markedly, the CO2-selective NbOFFIVE-1-Ni exhibits the highest CO2 gravimetric and volumetric uptake (ca. 1.3 mmol/g and 51.4 cm(3) (STP) cm(-3)) for a physical adsorbent at 400 ppm of CO2 and 298 K. Practically, NbOFFIVE-1-Ni offers the complete CO2 desorption at 328 K under vacuum with an associated moderate energy input of 54 kJ/mol, typical for the full CO2 desorption in conventional physical adsorbents but considerably lower than chemical sorbents. Noticeably, the contracted square-like channels, affording the close proximity of the fluorine centers, permitted the enhancement of the CO2-framework interactions and subsequently the attainment of an unprecedented CO2 selectivity at very low CO2 concentrations. The precise localization of the adsorbed CO2 at the vicinity of the periodically aligned fluorine centers, promoting the selective adsorption of CO2, is evidenced by the single-crystal X-ray diffraction study on NbOFFIVE-1-Ni hosting CO2 molecules. Cyclic CO2/N2 mixed-gas column breakthrough experiments under dry and humid conditions corroborate the excellent CO2 selectivity under practical carbon capture conditions. Pertinently, the notable hydrolytic stability positions NbOFFIVE-1-Ni as the new benchmark adsorbent for direct air capture and CO2 removal from confined spaces.

  14. Status of iodized salt coverage in urban slums of cuttack city, orissa.

    Science.gov (United States)

    Panigrahi, Ansuman; Mishra, Kaushik; Mohapatra, Bijayeeni

    2009-04-01

    For sustainable elimination of iodine deficiency disorders (IDD), it is necessary to consume adequately iodized salt on a regular basis and optimal iodine nutrition can be achieved through universal salt iodization. To assess the extent of use of adequately iodized salt in the urban slums of Cuttack. Using a stratified random multi-stage cluster sampling design, a cross-sectional study involving 336 households and 33 retail shops selected randomly from 11 slums of Cuttack was conducted in 2005. A predesigned pretested schedule was used to obtain relevant information and salt iodine was estimated qualitatively by using a spot testing kit and quantitatively using the iodometric titration method. Proportion, Chi-square test. Only 60.1% of the households in urban slums of Cuttack were using adequately iodized salt i.e., the iodine level in the salt was >/=15 ppm. Iodine deficiency was significantly marked in sample salts collected from katcha houses as compared with salts collected from pucca houses. Households with low financial status were using noniodized/inadequately-iodized salt. Both crystalline and refined salts were sold at all retail shops. Crystalline salts collected from all retailers had an iodine content < 15 ppm and refined salts collected from one retailer had iodine content < 15 ppm. About 48.5% of salt samples collected from retail shops were adequately iodized. In the urban slums of Cuttack, retailers were selling crystalline salts, which were inadequately iodized- this would be a setback in the progress towards eliminating IDD.

  15. Kinetic polymerization behavior of fluorinated monomers for dental use.

    Science.gov (United States)

    Kadoma, Yoshinori

    2010-10-01

    The kinetic polymerization behavior of 2,2,2-trifluoroethyl methacrylate (TFEMA), 1,1,1,3,3,3-hexafluoroisopropyl methacrylate (HFIPMA), 2,2,2-trifluoroethyl acrylate (TFEA) and 1,1,1,3,3,3-hexafluoroisopropyl acrylate (HFIPA) was determined by isothermal differential scanning calorimetry (DSC) and high-performance liquid chromatography (HPLC) in order to improve the properties of fluorinated powder-liquid adhesive resins. Conversion and heat of polymerization were calculated, and the solubility of the homopolymers in common solvents was examined. Comparison of their polymerization reactivity with that of MMA revealed that the overall rate of polymerization initiated by benzoyl peroxide (BPO) decreased in the order TFEA>MMA>TFEMA>HFIPA>HFIPMA. Based on the retention time of the monomer determined by HPLC, the hydrophobicity of the monomers was found to increase in the order MMAadhesive resins.

  16. Purification of commercial yttrium metal: Removal of fluorine

    Science.gov (United States)

    Takenouchi, A.; Otomo, T.; Niwa, K.; Sakai, M.; Saito, Y.; Kirigane, T.; Kosaka, M.; Michimura, S.; Hasegawa, S.; Nakamura, O.

    2017-06-01

    We have performed refining process of yttrium (Y) by removal of fluorine (F) residually existing in commercial Y metal. It was demonstrated that combination of conventional plasma arc melting and mechanical surface polishing is a powerful method for removal of F, the residual concentration of which was traced by energy dispersive X-ray spectroscopy of as processed material and X-ray photoemission spectroscopy of as deposited films, which were grown using the processed material as a deposition source. As a result, the concentration of F in our purified material was assessed to be smaller than 3.5 wt ppm, which is approximately 1.3 % of the initial F concentration present in the unpurified material (260 wt ppm).

  17. Fluorinated mercaptobenzothiazolates of lanthanides: Synthesis, structure and photoluminescence

    Science.gov (United States)

    Ilichev, Vasily A.; Blinova, Lubov I.; Rozhkov, Anton V.; Balashova, Tatyana V.; Rumyantcev, Roman V.; Fukin, Georgy K.; Bochkarev, Mikhail N.

    2017-11-01

    In search of new fully fluorinated ligands which effectively sensitized the lanthanide luminescence the 4,5,6,7-tetrafluoro-1,3-benzothiazol-2(3Н)-thione (HmbtF) was proposed. Based on this ligand a set of new complexes LnL3(THF)2 (Ln1) (Ln = Nd, Gd, Tb, Dy, Er, Yb) was synthesized and their luminescence were studied. The structure of the compounds was established with an example of Gd derivative. The triplet state energy of mbtF was found to be 21500 cm-1 that enables the resonant energy transfer to Dy3+, Tb3+, Nd3+ and Er3+ ions and stipulates metal-centered emission of some complexes. In case of Yb1 the observed luminescence of Yb3+ ion probably occurs due to the non-resonant energy transfer.

  18. Silicon-[18F]Fluorine Radiochemistry: Basics, Applications and Challenges

    Directory of Open Access Journals (Sweden)

    Carmen Wängler

    2012-03-01

    Full Text Available Silicon-[18F]fluorine (Si-18F radiochemistry has recently emerged alongside other unconventional approaches such as aluminum-18F and boron-18F based labeling strategies, reshaping the landscape of modern 18F-radiochemistry. All these novel methodologies are driven by the demand for more convenient 18F-labeling procedures to further disseminate one of the most sophisticated imaging technologies, Positron Emission Tomography (PET. The PET methodology requires special radionuclides such as 18F (one of the most prominent examples to be introduced into bioactive molecules. Si-18F radiochemistry contributed greatly towards the development of new radiopharmaceuticals for PET imaging. Herein, we describe the radiochemical basics of Si-18F bond formation, the application of Si-18F tracers for PET imaging, and additionally, the inherent chemical intricacies of this methodology.

  19. Projections of global emissions of fluorinated greenhouse gases in 2050

    Energy Technology Data Exchange (ETDEWEB)

    Gschrey, Barbara; Schwarz, Winfried [Oeko-Recherche Buero fuer Umweltforschung und -beratung GmbH, Frankfurt/Main (Germany)

    2009-11-15

    Emissions of fluorinated greenhouse gases are currently covered under the Montreal Protocol, which focuses on ozone-depleting substances such as CFCs (chlorofluorocarbons) and HCFCs (hydrochlorofluorocarbons), and under the Kyoto Protocol, which controls emissions of HFCs (hydrofluorocarbons), PFCs (perfluorocarbons) and SF{sub 6} (sulfur hexafluoride). This study bridges the gap between political regimes and their reporting systems by giving an overview of banks and emissions of all fluorinated gases in 2005, and projections of banks and emissions of fluorinated gases in 2050. The Montreal Protocol and its amendments will eventually result in the full phase out of CFCs and HCFCs. Developed countries have already completed the phase out of CFCs and will reach full phase out of HCFCs by 2020. Developing countries, in contrast, will phase out CFCs by 2010 and HCFCs by 2030. Although climate-friendly technology is available for most applications, the risk occurs that substitutes for ozone-depleting substances rely on HFCs, which cause global warming. This study determines global emissions of HFCs, PFCs and SF{sub 6} (Kyoto F-gases) in 2050 in a ''business-as-usual'' scenario. The global population is expected to increase to ca. 8.7 billion people, and high economic growth of 3.5% per year is assumed. Emissions in 2050 are quantified for each sector of application as well as for developed and developing countries based on growth rates of each sector. In 2050, total global emissions of fluorinated greenhouse gases are projected to amount to 4 GT CO{sub 2} eq. which equals ca. 5.9% of the total greenhouse gas emissions at this time. Compared to a relatively small share of F-gas emissions ranging around 1.3% of total greenhouse gas emissions in 2004, this percentage reflects an enormous increase. Relative to projected direct CO{sub 2} emissions alone, the 2050 F-gas emissions will even account for ca. 7.9%. In case of CO{sub 2} mitigation, this share

  20. Chalcogenide optical microwires cladded with fluorine-based CYTOP.

    Science.gov (United States)

    Li, Lizhu; Abdukerim, Nurmemet; Rochette, Martin

    2016-08-22

    We demonstrate optical transmission results of highly nonlinear As2Se3 optical microwires cladded with fluorine-based CYTOP, and compare them with microwires cladded with typical hydrogen-based polymers. In the linear optics regime, the CYTOP-cladded microwire transmits light in the spectral range from 1.3 µm up to >2.5 µm without trace of absorption peaks such as those observed using hydrogen-based polymer claddings. The microwire is also pumped in the nonlinear optics regime, showing multiple-orders of four-wave mixing and supercontinuum generation spanning from 1.0 µm to >4.3 µm. We conclude that with such a broadband transparency and high nonlinearity, the As2Se3-CYTOP microwire is an appealing solution for nonlinear optical processing in the mid-infrared.

  1. New cancer cells apoptosis agents: Fluorinated aza-heterocycles

    Science.gov (United States)

    Prima, D. O.; Baev, D. S.; Vorontsova, E. V.; Frolova, T. S.; Bagryanskaya, I. Yu.; Slizhov, Yu. G.; Tolstikova, T. G.; Makarov, A. Yu.; Zibarev, A. V.

    2017-09-01

    Fluorinated benzo-fused 1,3-diazoles, 1,2,3-triazoles, 1,2,5-thia/selenadiazoles and 1,4-diazines were synthesized and tried for cytotoxicity towards the Hep2 (laryngeal epidermoid carcinoma) cells. The diazoles, triazoles and selenadiazoles were cytotoxic with IC50 = 2.2-26.4 µM and induced the cells apoptosis at concentrations C = 1-25 µM. At the same time, they were nontoxic towards normal cells. Due to this, these scaffolds were used in the computer-aided molecular design of new antitumor agents. Particularly, novel 1,2,3-triazole and 1,3-diazole derivatives for the binding site of the PAS domain of the transcription factor HIF were designed and some of them synthesized for further study. Overall, new anticancer agents featuring apoptotic activity are suggested.

  2. Covalent Fluorination Strategies for the Surface Modification of Polydienes.

    Science.gov (United States)

    De Bruycker, Kevin; Delahaye, Maarten; Cools, Pieter; Winne, Johan; Prez, Filip E Du

    2017-06-01

    Nonreactive additives are widely applied to enhance polymer properties but can leach out of the material over time. In this work, two essentially different fluorinated additives bearing a triazolinedione moiety are synthesized and grafted on several polydiene backbones (acrylonitrile-butadiene-styrene, styrene-butadiene, and styrene-isoprene-styrene (SIS) copolymers), either by dip-coating or by reaction in solution. The resulting polymers are analyzed by contact angle goniometry, size exclusion chromatography, and NMR, infrared, and X-ray photoelectron spectroscopy. Independent of the modification procedure, the fluorophilic perfluoroalkyl additive is found at the material surface, thereby yielding a more hydrophobic surface. For SIS thermoplastic elastomers, for example, contact angles up to 125° can be obtained. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. An Overview of Liquid Fluoride Salt Heat Transport Systems

    Energy Technology Data Exchange (ETDEWEB)

    Holcomb, David Eugene [ORNL; Cetiner, Sacit M [ORNL

    2010-09-01

    , and this report also describes more recently developed technologies such as dry gas seals. This report also provides a high-level, parametric evaluation of LSHT loop performance to allow general intercomparisons between heat-transport fluid options as well as provide an overview of the properties and requirements for a representative loop. A compilation of relevant thermophysical properties of useful fluoride salts is also included for salt heat transport systems. Fluoride salts can be highly corrosive depending on the container materials selected, the salt chemistry, and the operating procedures used. The report includes an overview of the state-of-the-art in reduction-oxidation chemistry control methodologies employed to minimize corrosion issues. Salt chemistry control technology, however, remains at too low a level of understanding for widespread industrial usage. Loop operational issues such as start-up procedures and system freeze-up vulnerability are also discussed. Liquid fluoride salts are a leading candidate heat transport medium for high-temperature applications. This report provides an overview of the current status of liquid salt heat transport technology. The report includes a high-level, parametric evaluation of liquid fluoride salt heat transport loop performance to allow intercomparisons between heat-transport fluid options as well as providing an overview of the properties and requirements for a representative loop. Much of the information presented here derives from the earlier molten salt reactor program and a significant advantage of fluoride salts, as high temperature heat transport media is their consequent relative technological maturity. The report also includes a compilation of relevant thermophysical properties of useful heat transport fluoride salts. Fluoride salts are both thermally stable and with proper chemistry control can be relatively chemically inert. Fluoride salts can, however, be highly corrosive depending on the container

  4. 21 CFR 100.155 - Salt and iodized salt.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 2 2010-04-01 2010-04-01 false Salt and iodized salt. 100.155 Section 100.155 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION GENERAL Specific Administrative Rulings and Decisions § 100.155 Salt and iodized...

  5. Weak Intermolecular Hydrogen Bonds with Fluorine: Detection and Implications for Enzymatic/Chemical Reactions, Chemical Properties, and Ligand/Protein Fluorine NMR Screening.

    Science.gov (United States)

    Dalvit, Claudio; Vulpetti, Anna

    2016-05-23

    It is known that strong hydrogen-bonding interactions play an important role in many chemical and biological systems. However, weak or very weak hydrogen bonds, which are often difficult to detect and characterize, may also be relevant in many recognition and reaction processes. Fluorine serving as a hydrogen-bond acceptor has been the subject of many controversial discussions and there are different opinions about it. It now appears that there is compelling experimental evidence for the involvement of fluorine in weak intramolecular or intermolecular hydrogen bonds. Using established NMR methods, we have previously characterized and measured the strengths of intermolecular hydrogen-bond complexes involving the fluorine moieties CH2 F, CHF2 , and CF3 , and have compared them with the well-known hydrogen-bond complex formed between acetophenone and the strong hydrogen-bond donor p-fluorophenol. We now report evidence for the formation of hydrogen bonds involving fluorine with significantly weaker donors, namely 5-fluoroindole and water. A simple NMR method is proposed for the simultaneous measurement of the strengths of hydrogen bonds between an acceptor and a donor or water. Important implications of these results for enzymatic/chemical reactions involving fluorine, for chemical and physical properties, and for ligand/protein (19) F NMR screening are analyzed through experiments and theoretical simulations. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Learning SaltStack

    CERN Document Server

    Myers, Colton

    2015-01-01

    If you are a system administrator who manages multiple servers, then you know how difficult it is to keep your infrastructure in line. If you've been searching for an easier way, this book is for you. No prior experience with SaltStack is required.

  7. [Study of Interaction between Fluorinated Coating Glass and the Medicines].

    Science.gov (United States)

    Kawano, Yayoi; Otsu, Saki; Bamba, Takao; Hanawa, Takehisa

    2017-11-01

     The adsorption of active pharmaceutical ingredients on the surface of medical devices such as polyvinl chloride, ethylene-vinyl acetate copolymer and glass often prevent the acuurate dose of drug. At dispensing of pharmaceuticals, mètre glass (MG) has been widely used for dispensing syrup. When measuring the viscous syrup, it often takes long time to dispense the accurate volume due to their adhesiveness on the glass surface. In this study, we investigate the adhesion of various syrups to MG made with uncoated glass or glass with a strongly hydrophobic silicone or fluorinated coating in terms of the following formulation parameters: viscosity, surface tension, contact angle, and surface free energy. The contact angles for syrups on the coated glass surfaces were significantly higher than those on the uncoated glass surface. In addition, the relationship between surface tension and contact angle was examined. We found that the contact angle was independent of surface tension for the uncoated glass, while it increased with increasing surface tension for the coated glasses. These results can be explained as follows: the silicone or fluorinated coatings inhibit the hydrogen bonding that usually takes place between water and silanol and siloxane groups at glass surfaces. The coatings reduced the surface free energy and increased the hydrophobicity of the glass, reduced its wettability by the syrups, and thus reduced the adhesion loss for the syrups. It was considered that as for the hydrophobic action, properties of matter of sample influence the coated device by coating in order that it is reinforced.

  8. Uranium mineralization in fluorine-enriched volcanic rocks

    Energy Technology Data Exchange (ETDEWEB)

    Burt, D.M.; Sheridan, M.F.; Bikun, J.; Christiansen, E.; Correa, B.; Murphy, B.; Self, S.

    1980-09-01

    Several uranium and other lithophile element deposits are located within or adjacent to small middle to late Cenozoic, fluorine-rich rhyolitic dome complexes. Examples studied include Spor Mountain, Utah (Be-U-F), the Honeycomb Hills, Utah (Be-U), the Wah Wah Mountains, Utah (U-F), and the Black Range-Sierra Cuchillo, New Mexico (Sn-Be-W-F). The formation of these and similar deposits begins with the emplacement of a rhyolitic magma, enriched in lithophile metals and complexing fluorine, that rises to a shallow crustal level, where its roof zone may become further enriched in volatiles and the ore elements. During initial explosive volcanic activity, aprons of lithicrich tuffs are erupted around the vents. These early pyroclastic deposits commonly host the mineralization, due to their initial enrichment in the lithophile elements, their permeability, and the reactivity of their foreign lithic inclusions (particularly carbonate rocks). The pyroclastics are capped and preserved by thick topaz rhyolite domes and flows that can serve as a source of heat and of additional quantities of ore elements. Devitrification, vapor-phase crystallization, or fumarolic alteration may free the ore elements from the glassy matrix and place them in a form readily leached by percolating meteoric waters. Heat from the rhyolitic sheets drives such waters through the system, generally into and up the vents and out through the early tuffs. Secondary alteration zones (K-feldspar, sericite, silica, clays, fluorite, carbonate, and zeolites) and economic mineral concentrations may form in response to this low temperature (less than 200 C) circulation. After cooling, meteoric water continues to migrate through the system, modifying the distribution and concentration of the ore elements (especially uranium).

  9. Introducing the fluorine doped natural hydroxyapatite-titania nanobiocomposite ceramic

    Energy Technology Data Exchange (ETDEWEB)

    Karamian, Ebrahim [Advanced Materials Research Center, Faculty of Materials Engineering, Najafabad Branch, Islamic Azad University, Najafabad (Iran, Islamic Republic of); Abdellahi, Majid, E-mail: M.Abdellahi@Pa.iut.ac.ir [Advanced Materials Research Center, Faculty of Materials Engineering, Najafabad Branch, Islamic Azad University, Najafabad (Iran, Islamic Republic of); Khandan, Amirsalar [Young Researchers and Elite Club, Khomeinishahr Branch, Islamic Azad University, Isfahan (Iran, Islamic Republic of); Abdellah, Sana [Advanced Materials Research Center, Faculty of Materials Engineering, Najafabad Branch, Islamic Azad University, Najafabad (Iran, Islamic Republic of)

    2016-09-15

    In the present research, natural hydroxyapatite (NHA) was synthesized from bovine bones and then fluorine was doped into the NHA matrix to produce fluorine doped NHA (FNHA; natural fluor-hydroxyapatite) in optimum conditions. At the end an FNHA-TiO{sub 2} nanobiocomposite ceramic with excellent biocompatibility and good chemical stability was synthesized through a mechanochemical route and a subsequent two step sintering (TSS) process. Thermal gravimetric analysis (TGA), Differential scanning calorimetry (DSC), X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), inductive coupled plasma (ICP), and energy-dispersive X-ray spectroscopy (EDX) were used as the means for gathering and analysis of the results. According to the obtained results, TiO{sub 2} can prevent early decomposition of FNHA by the formation of the CaTiO{sub 3} phases and hence strengthen the interactions between the apatite particles which results in the increase of the mechanical properties. Besides, TiO{sub 2} provides more Si−OH nucleation sites for the formation of the apatite layers and hence more bioactivity. - Highlights: • This work begins with preparing natural hydroxyapatite from bovine bones via a simple method. • With increasing the TiO{sub 2} content reinforced in FNHA matrix, the compaction increases. • TiO{sub 2} can prevent early decomposition of FNHA by the formation of CaTiO{sub 3} phase. • TiO{sub 2} can strengthen the interactions between the apatite particles and increase of compaction. • With increasing TiO{sub 2} content, the Si−OH nucleation sites increases lead to more bioactivity.

  10. Lowering Salt in Your Diet

    Science.gov (United States)

    ... For Consumers Home For Consumers Consumer Updates Lowering Salt in Your Diet Share Tweet Linkedin Pin it More sharing options ... and can be used by individuals to replace salt in their diet. There are no known undesirable effects in healthy ...

  11. Carpinteria Salt Marsh Habitat Polygons

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — We identified five common habitat types in Carpinteria Salt Marsh: channels, pans (flats), marsh, salt flat and upland. We then drew polygons around each habitat...

  12. Salt ingestion caves.

    Directory of Open Access Journals (Sweden)

    Lundquist Charles A.

    2006-01-01

    Full Text Available Large vertebrate herbivores, when they find a salt-bearing layer of rock, say in a cliff face, can produce sizable voids where, overgenerations, they have removed and consumed salty rock. The cavities formed by this natural animal process constitute a uniqueclass of caves that can be called salt ingestion caves. Several examples of such caves are described in various publications. Anexample in Mississippi U.S.A., Rock House Cave, was visited by the authors in 2000. It seems to have been formed by deer orbison. Perhaps the most spectacular example is Kitum Cave in Kenya. This cave has been excavated to a length over 100 metersby elephants. An ancient example is La Cueva del Milodon in Chile, which is reported to have been excavated by the now extinctmilodon, a giant ground sloth. Still other possible examples can be cited. This class of caves deserves a careful definition. First, thecavity in rock should meet the size and other conventions of the locally accepted definition of a cave. Of course this requirement differsin detail from country to country, particularly in the matter of size. The intent is to respect the local conventions. The characteristicthat human entry is possible is judged to be a crucial property of any recognized cave definition. Second, the cavity should besignificantly the result of vertebrate animal consumption of salt-bearing rock. The defining process is that rock removed to form thecave is carried away in the digestive track of an animal. While sodium salts are expected to be the norm, other salts for which thereis animal hunger are acceptable. Also some other speleogenesis process, such as solution, should not be excluded as long as it issecondary in formation of a cave in question.

  13. Microbial Diversity of Culinary Salts

    OpenAIRE

    Muske, Galen; Baxter, Bonnie

    2016-01-01

    Extremophiles are exceptional microorganisms that live on this planet in extraordinarily harsh environments. One such extremophiles are Halophiles, salt-loving microorganisms that can survive in extreme salinity levels, and have been found to survive inside salt crystals. We were curious is about the potential diversity of halophiles surviving in salts harvested from around the world. For this experiment various culinary salts were suspended in a 23 % NaCL growth media broth and allowed to gr...

  14. Salt in bread - succesful?) Reduction of content in danish bread

    DEFF Research Database (Denmark)

    Knuthsen, Pia; Saxholt, Erling; Trolle, Ellen

    High intakes of sodium are associated with high blood pressure, elevated risk of cardiovascular diseases and early death. In the Nordic countries reduction of average sodium intake to about 2-2.7 g/d, or 5-7 g salt/d, is recommended. Main sources of salt in the diet are processed foods e.g. bread...... of view a gradual reduction would do in order to adapt to lower salt preference. To demonstrate a possible reduction, current salt levels must be assessed, and in the present study salt content of bread, covering Danish consumption in 2014, was investigated. When monitoring a possible trend samples...... studied must represent the current consumption. Thus getting an overview of market shares is important, and quite a challenge as selection of bread is changing continuously. A strategic sampling plan was made representing all relevant types of bread, based on information from manufacturers...

  15. Salt Tolerance in Rice: Focus on Mechanisms and Approaches

    Directory of Open Access Journals (Sweden)

    Inja Naga Bheema Lingeswara Reddy

    2017-05-01

    Full Text Available Salt tolerance is an important constrain for rice, which is generally categorized as a typical glycophyte. Soil salinity is one of the major constraints affecting rice production worldwide, especially in the coastal areas. Susceptibility or tolerance of rice plants to high salinity is a coordinated action of multiple stress responsive genes, which also interacts with other components of stress signal transduction pathways. Salt tolerant varieties can be produced by marker-assisted selection or genetic engineering by introducing salt-tolerance genes. In this review, we have updated on mechanisms and genes which can help in transferring of the salt tolerance into high-yielding rice varieties. We have focused on the need for integrating phenotyping, genomics, metabolic profiling and phenomics into transgenic and breeding approaches to develop high-yielding as well as salt tolerant rice varieties.

  16. Fluorine-containing quinazolines and their oxa and thia analogues: synthesis and biological activities

    Energy Technology Data Exchange (ETDEWEB)

    Nosova, Emiliya V [B N Yeltsin Urals State Technical University - UPI (Russian Federation); Lipunova, Galina N; Charushin, Valery N [I. Ya. Postovsky Institute of Organic Synthesis, Urals Branch of the Russian Academy of Sciences, Ekaterinburg (Russian Federation)

    2009-05-31

    Convenient methods for the synthesis of fluorine-containing quinazolines and their oxa and thia analogues are considered. Data on the prospects for using these compounds in medicine are given. Bibliography - 129 references.

  17. Fluorinated 5- and 7-membered carbacycle motifs by reaction of difluorocarbene with acetylene ethers.

    Science.gov (United States)

    Chia, Poh Wai; Bello, Davide; Slawin, Alexandra M Z; O'Hagan, David

    2013-03-18

    The reaction of acetylene ethers with difluorocarbene (CF(2)), generated from the Ruppert-Prakash reagent, unexpectedly gave rise to co-produced fluorinated bicyclic [2.1.1]-hex-2-ene and cyclohepta-1,4-diene ring products.

  18. Stability of corticosteroids under anaerobic conditions. C6 and C9 fluorine-containing corticosteroids

    NARCIS (Netherlands)

    Dekker, D.; Buijs, D.J.

    The decomposition of corticosteroids due to a fluorine atom at C6 and/or C9 is investigated. Chromatographic properties, the isolation and the structure elucidation of decomposition products are given.

  19. Nanoimprint Resist Material Containing Ultraviolet Reactive Fluorine Surfactant for Defect Reduction in Lithographic Fabrication

    National Research Council Canada - National Science Library

    Takei, Satoshi; Sekiguchi, Atsushi

    2012-01-01

    ... in nanoimprint patterning replication. The developed acrylate type nanoimprint resist material containing 4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,11-heptadecafluoro-2-hydroxyundecyl acrylate as an ultraviolet reactive fluorine surfactant...

  20. Fluorination of poly(dimethylsiloxane) surfaces by low pressure CF4 plasma : physicochemical and antifouling properties

    NARCIS (Netherlands)

    Cordeiro, A.L.; Nitschke, M.; Janke, A.; Helbig, R.; D'Souza, F.; Donnelly, G.T.; Willemsen, P.R.; Werner, C.

    2009-01-01

    Fluorinated surface groups were introduced into poly(dimethylsiloxane) (PDMS) coatings by plasma treatment using a low pressure radio frequency discharge operated with tetrafluoromethane. Substrates were placed in a remote position downstream the discharge. Discharge power and treatment time were

  1. Impact of Backbone Fluorination on π-Conjugated Polymers in Organic Photovoltaic Devices: A Review

    Directory of Open Access Journals (Sweden)

    Nicolas Leclerc

    2016-01-01

    Full Text Available Solution-processed bulk heterojunction solar cells have experienced a remarkable acceleration in performances in the last two decades, reaching power conversion efficiencies above 10%. This impressive progress is the outcome of a simultaneous development of more advanced device architectures and of optimized semiconducting polymers. Several chemical approaches have been developed to fine-tune the optoelectronics and structural polymer parameters required to reach high efficiencies. Fluorination of the conjugated polymer backbone has appeared recently to be an especially promising approach for the development of efficient semiconducting polymers. As a matter of fact, most currently best-performing semiconducting polymers are using fluorine atoms in their conjugated backbone. In this review, we attempt to give an up-to-date overview of the latest results achieved on fluorinated polymers for solar cells and to highlight general polymer properties’ evolution trends related to the fluorination of their conjugated backbone.

  2. Spontaneous aggregation of lithium ion coordination polymers in fluorinated electrolytes for high-voltage batteries.

    Science.gov (United States)

    Malliakas, Christos D; Leung, Kevin; Pupek, Krzysztof Z; Shkrob, Ilya A; Abraham, Daniel P

    2016-04-28

    Fluorinated carbonates are pursued as liquid electrolyte solvents for high-voltage Li-ion batteries. Here we report aggregation of [Li(+)(FEC)3]n polymer species in fluoroethylene carbonate containing electrolytes and scrutinize the causes for this behavior.

  3. Tuning the electronic transport properties of graphene through functionalisation with fluorine

    Directory of Open Access Journals (Sweden)

    Dubois Marc

    2011-01-01

    Full Text Available Abstract We demonstrate the possibility to tune the electronic transport properties of graphene mono-layers and multi-layers by functionalisation with fluorine. For mono-layer samples, with increasing the fluorine content, we observe a transition from electronic transport through Mott variable range hopping (VRH in two dimensions to Efros-Shklovskii VRH. Multi-layer fluorinated graphene with high concentration of fluorine show two-dimensional Mott VRH transport, whereas CF0.28 multi-layer flakes exhibit thermally activated transport through near neighbour hopping. Our experimental findings demonstrate that the ability to control the degree of functionalisation of graphene is instrumental to engineer different electronic properties in graphene materials.

  4. Fast Spectrum Molten Salt Reactor Options

    Energy Technology Data Exchange (ETDEWEB)

    Gehin, Jess C [ORNL; Holcomb, David Eugene [ORNL; Flanagan, George F [ORNL; Patton, Bruce W [ORNL; Howard, Rob L [ORNL; Harrison, Thomas J [ORNL

    2011-07-01

    During 2010, fast-spectrum molten-salt reactors (FS-MSRs) were selected as a transformational reactor concept for light-water reactor (LWR)-derived heavy actinide disposition by the Department of Energy-Nuclear Energy Advanced Reactor Concepts (ARC) program and were the subject of a preliminary scoping investigation. Much of the reactor description information presented in this report derives from the preliminary studies performed for the ARC project. This report, however, has a somewhat broader scope-providing a conceptual overview of the characteristics and design options for FS-MSRs. It does not present in-depth evaluation of any FS-MSR particular characteristic, but instead provides an overview of all of the major reactor system technologies and characteristics, including the technology developments since the end of major molten salt reactor (MSR) development efforts in the 1970s. This report first presents a historical overview of the FS-MSR technology and describes the innovative characteristics of an FS-MSR. Next, it provides an overview of possible reactor configurations. The following design features/options and performance considerations are described including: (1) reactor salt options-both chloride and fluoride salts; (2) the impact of changing the carrier salt and actinide concentration on conversion ratio; (3) the conversion ratio; (4) an overview of the fuel salt chemical processing; (5) potential power cycles and hydrogen production options; and (6) overview of the performance characteristics of FS-MSRs, including general comparative metrics with LWRs. The conceptual-level evaluation includes resource sustainability, proliferation resistance, economics, and safety. The report concludes with a description of the work necessary to begin more detailed evaluation of FS-MSRs as a realistic reactor and fuel cycle option.

  5. Natural production of fluorinated compounds and biotechnological prospects of the fluorinase enzyme.

    Science.gov (United States)

    Carvalho, Maria F; Oliveira, Rui S

    2017-11-01

    Fluorinated compounds are finding increasing uses in several applications. They are employed in almost all areas of modern society. These compounds are all produced by chemical synthesis and their abundance highly contrasts with fluorinated molecules of natural origin. To date, only some plants and a handful of actinomycetes species are known to produce a small number of fluorinated compounds that include fluoroacetate (FA), some ω-fluorinated fatty acids, nucleocidin, 4-fluorothreonine (4-FT), and the more recently identified (2R3S4S)-5-fluoro-2,3,4-trihydroxypentanoic acid. This largely differs from other naturally produced halogenated compounds, which totals more than 5000. The mechanisms underlying biological fluorination have been uncovered after discovering the first actinomycete species, Streptomyces cattleya, that is capable of producing FA and 4-FT, and a fluorinase has been identified as the enzyme responsible for the formation of the C-F bond. The discovery of this enzyme has opened new perspectives for the biotechnological production of fluorinated compounds and many advancements have been achieved in its application mainly as a biocatalyst for the synthesis of [(18)F]-labeled radiotracers for medical imaging. Natural fluorinated compounds may also be derived from abiogenic sources, such as volcanoes and rocks, though their concentrations and production mechanisms are not well known. This review provides an outlook of what is currently known about fluorinated compounds with natural origin. The paucity of these compounds and the biological mechanisms responsible for their production are addressed. Due to its relevance, special emphasis is given to the discovery, characterization and biotechnological potential of the unique fluorinase enzyme.

  6. Partially fluorinated aarylene polyethers and their ternary blends with PBI and H3PO4

    DEFF Research Database (Denmark)

    Li, Qingfeng; Jensen, Jens Oluf; Pan, Chao

    2008-01-01

    Ternary blend membranes based on sulphonated partially fluorinated arylene polyether, polybenzimidazole (PBI) and phosphoric acid were prepared and characterised as electrolyte for high temperature proton exchange membrane fuel cells. Partially fluorinated arylene polyether was first prepared from......% and modulus of 50 MPa at 150 degrees C. Based on these ternary membranes large MEAs with an active area of 256 cm(2) have been prepared for a 2 kW(el) stack showing good performance and reproducibility....

  7. Effects of fluorine substitution on the edge-to-face interaction of the benzene dimer.

    Science.gov (United States)

    Riley, Kevin E; Merz, Kenneth M

    2005-09-22

    To gain some insight into the effects of fluorination on the aromatic-aromatic interactions found in protein-ligand complexes, like those observed in the set of N-(4-sulfamylbenzoyl)benzylamine (SBB) inhibitors bound to Human Carbonic Anhydrase II (HCAII), we have produced potential energy curves for the edge-to-face interactions of a set of fluorinated benzene dimer compounds. All calculations were carried out at the MP2/aug-cc-pVDZ level of theory using the counterpoise method of Boys and Bernardi (Boys, S. F.; Bernardi, F. Mol. Phys. 1970, 19, 553) to account for the basis set superposition error. Fluorine substitutions are made onto the face molecule of the edge-to-face benzene dimer. As one might expect, the substitution of additional fluorines into this system generally resulted in a decrease of the binding energy. It was also found that the positioning of the fluorine substituents on isosubstituted compounds has a large effect on the total binding energy of these types of systems. More specifically, complexes with fluorines that are substituted closer to the hydrogen atoms of the edge benzene will tend to be stabilized by an electrostatic interaction between the partially negative fluorine atoms and the partially positive hydrogen atoms. However, our findings do not explain the recent crystallographic findings for the SBB-HCAII protein-ligand complex, where increased fluorination resulted in closer edge-to-face contacts, which suggests that there are factors, other than edge-to-face aromatic interactions, influencing this system's behavior.

  8. Fluorine analysis in serpentinite rocks by proton induced gamma-ray emission

    Science.gov (United States)

    Przybyłowicz, W.; Szymczyk, S.; Kajfosz, J.

    1986-04-01

    The 19F(p,p'γ) 19F reaction has been applied for the determination of fluorine in serpentinite rocks from Lower Silesia (South-West Poland). Rocks representing different degrees of alteration of primary peridotite into serpentinite were analysed. Measured fluorine concentrations varied from 140 to 300 ppm. PIGE proved to be an adequate, sufficiently accurate and convenient technique for analysing F and other light element concentrations (Al, Mg, Na) in serpentinites as well as in other geological samples.

  9. Evidence for Stable High Temperature Ferromagnetism in Fluorine Treated C60

    Science.gov (United States)

    2013-01-01

    Evidence for Stable High Temperature Ferromagnetism in Fluorine Treated C60 Rajen Patel and Frank J. Owens...microscopy, and ferromagnetic resonance that exposure of C60 to fluorine at 160 0C produces a stable ferromagnetic material with a Curie temperature well...has C60 imbedded in it. Based on previous experimental observations and molecular orbital calculations, it is suggested that the ferromagnetism is

  10. Influence of the chemical bond on the K emission spectrum of oxygen and fluorine.

    Science.gov (United States)

    Koster, A. S.

    1971-01-01

    The K emission spectrum of oxygen and fluorine from a number of simple oxides and fluorides is divided into three to six sub-peaks. The spectra of many of these oxides and fluorides resemble one another owing to their basically ionic bonding. Certain sub-peaks, however, are ascribed to cross-over transitions and partially covalent energy levels. The different fluorine spectrum of Teflon is due to the hybrid nature of its covalent bonds.

  11. Theoretical Assessment of Fluorinated Phospholipids in the Design of Liposomal Drug-Delivery Systems

    DEFF Research Database (Denmark)

    Madsen, Jesper J.united st; Fristrup, Peter; Peters, Günther H.J.

    2016-01-01

    ,alpha-difluoro (F-2-ProAEL) conjugates of (R)-1-O-hexadecyl-2-palmitoyl-sn-glycero-3-phoshocholineglycerol (ProAEL). Our results provide a theoretical assessment of the potential usefulness of these fluorinated lipids in the rational design of liposomal drug-delivery systems. The a-fluorine-substituted phospholipid...... properties and that are still subjects for important and pharmaceutically proven drug-delivery mechanisms....

  12. An approach to better understanding of salt weathering on stone monuments - the "petraSalt" research project

    Science.gov (United States)

    Heinrichs, K.; Azzam, R.

    2012-04-01

    Salt weathering is known as a major cause of damage on stone monuments. However, processes and mechanisms of salt weathering still can not be explained satisfactorily. From the expertś point of view, better understanding of salt weathering deserves further comprehensive in-situ investigation jointly addressing active salt weathering processes and controlling factors. The 'petraSalt' research project takes this approach. The rock-cut monuments of Petra / Jordan were selected for studies, since stone type and spectra of monument exposure regimes, environmental influences, salt loading and weathering damage are representative for many stone monuments worldwide. The project aims at real-time / real-scale weathering models that depict characteristic interdependencies between stone properties, monument exposure regimes, environmental influences, salt loading and salt weathering damage. These models are expected to allow reliable rating and interpretation of aggressiveness and damage potential of the salt weathering regimes considering their variability under range of lithology, monument exposure scenarios, environmental conditions and time. The methodological approach systematically combines assessment of weathering damage (type, extent, spatial distribution and progression of damage), assessment of monument exposure characteristics and environmental influences acting on the monuments (monument orientation / geometry, lithology, rain impact, water run-off, rising humidity, wind impact, insolation, heating-cooling and drying-wetting behaviour, etc.), engineering geological studies (structural discontinuities and related failure processes) and investigation of salt loading (type, concentration, spatial distribution and origin of salt, salt crystallization / dissolution, phase transitions, etc.). Besides established methods, very innovative technologies are applied in the course of investigation such as high-resolution 3D terrestrial laser scanning (TLS) and wireless

  13. Coastal Meringues: Are Salt Marshes Inflated with Excess Void Spaces?

    Science.gov (United States)

    Gunnell, J. R.

    2016-02-01

    Failure to stay above sea level is among many ways that salt marshes may be destroyed. This race against the sea is carried out by vertical accretion. Accretion is partly the accumulation of material mediated by vegetative and sedimentary feedbacks. Prognoses for salt marshes based on studies of these variables have proven useful, but they may also be failing to read between the lines. After all, the majority of a salt marsh's volume is typically comprised of void spaces, which seem to be under-examined in our current predictions of salt marsh survival. Salt marshes may be inflated with excess void spaces, occupying greater volumes than sedimentary predictions would otherwise assume. To test this hypothesis, benthic porosity measurements were drawn from a USGS database of thousands of seabed samples along the U.S. Atlantic and Gulf coasts. Seabed porosities were used to geostatistically interpolate expected porosities at selected salt marsh sites. Measurements of known salt marsh porosities were drawn from several case studies in the literature. These salt marsh porosity measurements were georeferenced so they could be compared to the expected seabed porosity determined by spatial interpolation. Initial results show that these salt marshes tend to be more porous than the benthic sediments surrounding them. This excess porosity can be an important contributor to marsh volume (i.e. elevation), and ultimately to marsh survival. Furthermore, it raises several questions about the source of this void space and the mechanism of its retention. Salt marsh volume appears to be greater than we would expect based on the sum of its parts. Therefore, predictions of salt marsh accretion may systematically underestimate void volumes and be overly pessimistic about marsh response to relative sea level rise.

  14. A Rapid Deposition of Fluorine Doped Zinc Oxide Using the Atmospheric Pressure Chemical Vapour Deposition Method

    Science.gov (United States)

    Najafi, Navid; Rozati, S. M.

    2018-03-01

    Fluorine-doped zinc oxide (FZO) (ZnO:F) thin films were manufactured by atmospheric pressure chemical vapor deposition (APCVD) on glass substrates using zinc acetate dihydrate [C4H6O4Zn·2H2O, ZnAc] and ammonium fluoride (NH4F) as the source of fluorine with deposition duration of only 120 s for each sample. The effects of different amounts of fluorine as the dopant on the structural, electrical and optical properties of FZO thin films were investigated. The results show a polycrystalline structure at higher temperatures compared to amorphous structure at lower temperatures. The x-ray diffraction patterns of the polycrystalline films were identified as a hexagonal wurtzite structure of zinc oxide (ZnO) with the (002) preferred orientation. Also, the sheet resistance decreased from 17.8 MΩ/□ to 28.9 KΩ/□ for temperatures 325°C to 450°C, respectively. In order to further decrease the sheet resistance of the undoped ZnO thin films, fluorine was added using NH4F as the precursor, and again a drastic change in sheet resistance of only 17.7 Ω/□ was obtained. Based on the field emission scanning electron microscopy images, the fluorine concentration in CVD source is an important factor affecting the grain size and modifies electrical parameters. Ultraviolet-visible measurements revealed reduction of transparency of the layers with increasing fluorine as the dopant.

  15. Determination of carcinogenic fluorine in cigarettes using pulsed UV laser-induced breakdown spectroscopy.

    Science.gov (United States)

    Gondal, Mohammed A; Habibullah, Yusuf B; Oloore, Luqman E; Iqbal, Mohammed A

    2015-06-10

    A spectrometer based on pulsed UV laser-induced breakdown spectroscopy (LIBS) and a highly sensitive intensified charged coupled device camera was developed to determine the carcinogenic substances like fluorine in various brands of cigarettes available commercially. In order to achieve the high sensitivity required for the determination of trace amounts of fluoride in cigarettes and eventually the best limit of detection, the experimental parameters (influence of incident laser energy on LIBS signal intensity and time response of plasma emission) were optimized. In addition, the plasma parameters like electron temperature and electron density were evaluated using Boltzman's plot for cigarette tobacco for the first time. To the best of our knowledge, LIBS has never been applied to determine the fluorine concentration in cigarettes. Along with the detection of fluorine, other trace metals like Ba, Ca, Ni, Cu, and Na were also detected in cigarettes. For determination of the concentration of fluorine, calibration curve was drawn by preparing standard samples in various fluoride concentrations in tobacco matrix. The concentration of fluorine in different cigarette tobacco samples was 234, 317, 341, and 360 ppm respectively, which is considered to be much higher than the safe permissible limits. The limit of detection of our LIBS spectrometer was 14 ppm for fluorine.

  16. A Rapid Deposition of Fluorine Doped Zinc Oxide Using the Atmospheric Pressure Chemical Vapour Deposition Method

    Science.gov (United States)

    Najafi, Navid; Rozati, S. M.

    2017-12-01

    Fluorine-doped zinc oxide (FZO) (ZnO:F) thin films were manufactured by atmospheric pressure chemical vapor deposition (APCVD) on glass substrates using zinc acetate dihydrate [C4H6O4Zn·2H2O, ZnAc] and ammonium fluoride (NH4F) as the source of fluorine with deposition duration of only 120 s for each sample. The effects of different amounts of fluorine as the dopant on the structural, electrical and optical properties of FZO thin films were investigated. The results show a polycrystalline structure at higher temperatures compared to amorphous structure at lower temperatures. The x-ray diffraction patterns of the polycrystalline films were identified as a hexagonal wurtzite structure of zinc oxide (ZnO) with the (002) preferred orientation. Also, the sheet resistance decreased from 17.8 MΩ/□ to 28.9 KΩ/□ for temperatures 325°C to 450°C, respectively. In order to further decrease the sheet resistance of the undoped ZnO thin films, fluorine was added using NH4F as the precursor, and again a drastic change in sheet resistance of only 17.7 Ω/□ was obtained. Based on the field emission scanning electron microscopy images, the fluorine concentration in CVD source is an important factor affecting the grain size and modifies electrical parameters. Ultraviolet-visible measurements revealed reduction of transparency of the layers with increasing fluorine as the dopant.

  17. Provenance and geochemical behavior of fluorine in the soils of an endemic fluorosis belt, central Iran

    Science.gov (United States)

    Dehbandi, Reza; Moore, Farid; Keshavarzi, Behnam

    2017-05-01

    The concentration of fluorine, major, trace and rare earth elements (REEs) were used to estimate the probable sources and provenance of fluorine in the soils of an endemic fluorosis belt in central Iran. Total fluorine (TF) in soils varied from 146 to 406 mg/kg with a mean of 277.5 mg/kg. Calculated enrichment factor (EF) and single factor pollution index (SFPI) revealed that the majority of soil samples were moderately contaminated by fluorine. The very strong positive correlation of TF with weathering indices and soil's fine sized fractions indicated that chemical weathering and alteration of parent rocks/soils are the main controlling factors of fluorine behavior in soils. Fluorine affinity to immobile transition trace elements and REEs suggested the role of heavy minerals as the potential F host phases. Modal mineralogy along with SEM-EDX analysis indicated that apatite, fluorapophyllite, epidote, biotite, muscovite and chlorite, as well as, clay minerals are the main F-bearing minerals in the studied soils. Discriminant, bivariate and ternary diagrams of elemental compositions displayed similar geochemical signature of soils to intermediate-acidic rocks and local shales. Based on the weathering indices, soils were immature and showed a non-steady state weathering trend from upper continental crust (UCC), acidic and intermediate igneous source rocks towards shale composition possibly due to mixing of moderately weathered and un-weathered sources of different primary compositions.

  18. Determination of fluorine contents in plant samples by means of facilitated extraction with enzyme.

    Science.gov (United States)

    Lee, Junseok; An, Jinsung; Yoon, Hye-On

    2015-01-01

    In this study, facilitated extraction with enzyme was employed for the first time to extract fluorine (F) from plants. Feasibility of the proposed method for F analysis was assessed by comparing with the alkali fusion-ion selective electrode (ISE) method. In the extraction procedure, 30 mg of a protease and 0.1 g of a plant sample were added in 10 mL of deionized water. In the absence of sonication, the solution was mechanically shaken for 10 s. A variety of parameters (i.e., the amounts of enzymes used, physical treatment conditions applied, extraction time, temperature, and pH) were optimized to enhance the extraction efficiency of the proposed method. The suitability of the proposed method for various plant samples (i.e., grass, perilla, peanut, hot pepper, and eggplant) was also evaluated. The proposed method involves decreased operation time, simplified extraction procedures, and minimal consumption of hazardous reagents and solvents in comparison with other existing methods. Experimental results demonstrated that facilitated extraction with enzyme is appropriate for the rapid determination of F content in plant samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Optoelectrochemical biorecognition by optically transparent highly conductive graphene-modified fluorine-doped tin oxide substrates.

    Science.gov (United States)

    Lamberti, F; Brigo, L; Favaro, M; Luni, C; Zoso, A; Cattelan, M; Agnoli, S; Brusatin, G; Granozzi, G; Giomo, M; Elvassore, N

    2014-12-24

    Both optical and electrochemical graphene-based sensors have gone through rapid development, reaching high sensitivity at low cost and with fast response time. However, the complex validating biochemical operations, needed for their consistent use, currently limits their effective application. We propose an integration strategy for optoelectrochemical detection that overcomes previous limitations of these sensors used separately. We develop an optoelectrochemical sensor for aptamer-mediated protein detection based on few-layer graphene immobilization on selectively modified fluorine-doped tin oxide (FTO) substrates. Our results show that the electrochemical properties of graphene-modified FTO samples are suitable for complex biological detection due to the stability and inertness of the engineered electrodic interface. In addition, few-layer immobilization of graphene sheets through electrostatic linkage with an electrochemically grafted FTO surface allows obtaining an optically accessible and highly conductive platform. As a proof of concept, we used insulin as the target molecule to reveal in solution. Because of its transparency and low sampling volume (a few microliters), our sensing unit can be easily integrated in lab-on-a-chip cell culture systems for effectively monitoring subnanomolar concentrations of proteins relevant for biomedical applications.

  20. Analysis of fluorine in coal. Sekitanchu no fusso bunseki ni tsuite

    Energy Technology Data Exchange (ETDEWEB)

    Oka, H.; Baba, H. (The Chugoku Electric Power Co. Inc., Hiroshima (Japan))

    1991-03-20

    Analysis of fluorine in coal being not established in method at present, pointing out is made of large differential due to change in analysis method and other problems. Then, adoption being made of alkali fusion method, bomb method and combustion tube method as a pretreatment method, and lanthanum-alizarin complexone absorption spectrophotometry and ion electrode method, standardized per JIS K 0102 to test the exhaust water from the plant, as a quantitative analysis method, comparison was studied among 9 types of analysis method, selected by combining the above methods. As for test material, 27 oversea coal specimens (covering 7 places of production and 18 brands) and 1 standard material coal specimen were used, and distillation-operated, as influence of ash content was taken into consideration after the pretreatment, or mashed by adding reagent thereto. As a result, it was known that the skillfulness is required against a possible obtainment of lower value in case of using the alkali fusion method for the pretreatment and that the bomb method and combustion tube method for it give a comparatively good result. 4 figs., 6 tabs.

  1. Fluorine-Containing ABC Linear Triblock Terpolymers: Synthesis and Self-assembly in Solution

    Energy Technology Data Exchange (ETDEWEB)

    He, Lihong [ORNL; Hinestrosa Salazar, Juan P [ORNL; Pickel, Joseph M [ORNL; Kilbey, II, S Michael [ORNL; Mays, Jimmy [ORNL; Zhang, Shanju [Georgia Institute of Technology; Bucknall, David G. [Georgia Institute of Technology; Hong, Kunlun [ORNL

    2011-01-01

    In this paper a fluorine-containing monomer, 2-fluroroethyl methacrylate (2FEMA) was used to synthesize the linear triblock terpolymer poly(n-butyl methacrylate)-poly(methyl methacrylate)-poly(2-fluoroethyl methacrylate) (PnBMA-PMMA-P2FEMA). A kinetic study of the homopolymerization of 2FEMA by reversible addition-fragmentation chain transfer (RAFT) polymerization showed that it demonstrates living character and produces well defined polymers with reasonably narrow polydispersities (~1.30). Triblock terpolymers were prepared sequentially using a purified Macro-CTA at 70 oC, resulting in final terpolymers with high Dp for each block (>150) and with polydispersities between 1.6 and 2.1. The structure and molecular weights of the resultant PnBMA-PMMA-P2FEMA triblock terpolymers were characterized via 1H NMR, 19F NMR, and gel permeation chromatography (GPC). Self-assembly of these polymers was carried out in a selective solvent and the micellar aggregates (MAs) thereby formed were analyzed using scanning electron microscopy (SEM) and dynamic light scattering (DLS). It was confirmed from SEM that these copolymers could directly self-organize into large compound micelles in tetrahydrofuran/methanol with different diameters, depending on polymer composition.

  2. [Clinical characteristics of patients with essential hypertension regarding salt intake].

    Science.gov (United States)

    Mediavilla García, J D; Fernández Torres, C; Aliaga Martínez, L; León Ruiz, L; Sabio Sánchez, M; Jiménez Alonso, J

    2001-11-01

    A number of epidemiologic and experimental studies have revealed the close relationship between salt intake and blood pressure. The objective of this study was to know the salt intake among 293 not previously treated hypertensive patients and to identify their clinical characteristics that would allow us to define the profile of patients with high sodium intake. Hypertensive patients who first attended a specialized high blood pressure (HBP) clinic not previously treated with drugs, at least for the last month were selected. Sodium 24 h urinary excretion was determined on two occasions, as sodium intake index. Thirteen percent of patients had a salt intake lower than 100 mEq/24 h and 35% of patients higher than 200 mEq/24 h. Sodium intake was higher among men, younger patients, those with a higher Quetelet index, smokers, higher socioeconomic status, and less years with IBP. No differences were observed between salt intake among hypertensive patients with associated diabetes or hyperlipidemia. The Quetelet index, sex, age and smoking were identified as independent variables for salt intake by the multiple linear regression analysis. No correlation was found between salt intake and blood pressure. In conclusion, a high sodium intake was observed in our setting among hypertensive patients who had previously been advised to moderate salt intake. The highest salt intake was observed among men, youths, obese and smokers.

  3. Mixed salt crystallisation fouling

    CERN Document Server

    Helalizadeh, A

    2002-01-01

    The main purpose of this investigation was to study the mechanisms of mixed salt crystallisation fouling on heat transfer surfaces during convective heat transfer and sub-cooled flow boiling conditions. To-date no investigations on the effects of operating parameters on the deposition of mixtures of calcium sulphate and calcium carbonate, which are the most common constituents of scales formed on heat transfer surfaces, have been reported. As part of this research project, a substantial number of experiments were performed to determine the mechanisms controlling deposition. Fluid velocity, heat flux, surface and bulk temperatures, concentration of the solution, ionic strength, pressure and heat transfer surface material were varied systematically. After clarification of the effect of these parameters on the deposition process, the results of these experiments were used to develop a mechanistic model for prediction of fouling resistances, caused by crystallisation of mixed salts, under convective heat transfer...

  4. Complex molecular mechanisms underlying seedling salt tolerance in rice revealed by comparative transcriptome and metabolomic profiling

    Science.gov (United States)

    Wang, Wen-Sheng; Zhao, Xiu-Qin; Li, Min; Huang, Li-Yu; Xu, Jian-Long; Zhang, Fan; Cui, Yan-Ru; Fu, Bin-Ying; Li, Zhi-Kang

    2016-01-01

    To understand the physiological and molecular mechanisms underlying seedling salt tolerance in rice (Oryza sativa L.), the phenotypic, metabolic, and transcriptome responses of two related rice genotypes, IR64 and PL177, with contrasting salt tolerance were characterized under salt stress and salt+abscisic acid (ABA) conditions. PL177 showed significantly less salt damage, lower Na+/K+ ratios in shoots, and Na+ translocation from roots to shoots, attributed largely to better salt exclusion from its roots and salt compartmentation of its shoots. Exogenous ABA was able to enhance the salt tolerance of IR64 by selectively decreasing accumulation of Na+ in its roots and increasing K+ in its shoots. Salt stress induced general and organ-specific increases of many primary metabolites in both rice genotypes, with strong accumulation of several sugars plus proline in shoots and allantoin in roots. This was due primarily to ABA-mediated repression of genes for degradation of these metabolites under salt. In PL177, salt specifically up-regulated genes involved in several pathways underlying salt tolerance, including ABA-mediated cellular lipid and fatty acid metabolic processes and cytoplasmic transport, sequestration by vacuoles, detoxification and cell-wall remodeling in shoots, and oxidation–reduction reactions in roots. Combined genetic and transcriptomic evidence shortlisted relatively few candidate genes for improved salt tolerance in PL177. PMID:26512058

  5. Thermochemical Properties of Nicotine Salts

    Directory of Open Access Journals (Sweden)

    Riggs DM

    2014-12-01

    Full Text Available The thermal gravimetric analysis (TGA and differential scanning calorimetry (DSC results presented in this report clearly show that the thermal stability and the endothermic peak nicotine release temperatures are different for different nicotine salts and these temperatures appear to be linked to the general microstructural details of the salt itself. In addition, the peak nicotine release temperatures are highly dependent upon the sample size used. The heat of vaporization for neat (non-protonated nicotine is also sample-size dependent. The TGA data showed that the least stable of the salts tested at elevated temperatures was the liquid salt nicotine triacetate followed by the crystalline materials (e.g., nicotine gallate and finally, the amorphous salts (e.g., nicotine alginate. The DSC results revealed that the liquid and crystalline salts exhibit nicotine release endotherms that are strongly related to the sample weight being tested. The amorphous salts show nicotine endotherm peak temperatures that are nearly independent of the sample weight. The range of peak nicotine release temperatures varied depending upon the specific salts and the sample size from 83 oC to well over 200 oC. Based on these results, the evolution of nicotine from the nicotine salt should be expected to vary based on the composition of the salt, the details of its microstructure, and the amount of nicotine salt tested.

  6. Microemulsion of Molten Salts

    Science.gov (United States)

    1991-02-01

    then to an oil-rich, upper phase as salinity increases in a system of brine/octane/ TRS surfactant/tertiary amyl alcohol . Borkovec et al. (1988) have...11 4. Partial Pseudotemary Phase Diagram .................................. 12 5. Micrograph of Molten Salts/SDS/Pentanol/Decane System...negligible interfacial tension between microdomains. Theoretical work in ternary and pseudotemary systems has shown that the middle phase is a

  7. Porous fluorinated SnO(2) hollow nanospheres: transformative self-assembly and photocatalytic inactivation of bacteria.

    Science.gov (United States)

    Liu, Shengwei; Huang, Guocheng; Yu, Jiaguo; Ng, Tsz Wai; Yip, Ho Yin; Wong, Po Keung

    2014-02-26

    Highly porous surface fluorinated SnO2 hollow nanospheres (SnO2(F) HNS) were produced in high yield by a hydrothermal treatment of stannous fluoride in the presence of hydrogen peroxide. Two important processes in terms of oriented self-assembly and in situ self-transformation were highlighted for the formation of as-prepared SnO2(F) HNS, which were largely relying on the directing effects of selected specific chemical species in the present synthesis system. Significantly, these SnO2(F) HNS showed considerable activity in photocatalytic inactivation of a surface negatively charged bacterium, Escherichia coli K-12, in aqueous saline solution. The dominant reactive species involved in the inactivation process were also identified.

  8. FY 1995 development of fluorinated hydriding alloys with multi functional and functionally-graded surface and their application to energy conversion devices; 1995 nendo keishagata fukugo kino wo hyomen ni motsu suiso kyuzo gokin no kaihatsu to energy henkan gijutsu eno oyo

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    The project is the extended researches of a fluorination technique invented by the project leader (Suda) for improving the surface properties and characteristics of conventional hydriding alloys from the following viewpoints; (1) To investigate the roles of fluorinated surface during hydrogen uptake both in the gas-solid and the electrochemical reactions. (2) To elucidate the factors which increase the protective nature of the surface. (3) To develop a material design procedure for synthesizing thin layer of functionally graded surface which is composed of metallic Ni and the fluoride compound. (1) An advanced fluorination technique was developed to incorporate metallic Ni in the surface fluoride layer. (2) Metallic Ni was successfully distributed in a functionally graded manner in the Surface fluoride layer. (3) Through the technique developed, the following properties and characteristics were successfully donated in the fluorinated hydriding alloys such as AB{sub 5}, AB{sub 2}, and AB; (3-1)Surface oxides which act as the resistant layer to the hydrogen up take was completely eliminated to result in the enhancement of the initial activation characteristics. (3-2) Hydrogen selectivity and permeability was greatly improved. (3-3) Surface protective nature against the impurity gases and contaminants was significantly improved. (3-4) Initial activation characteristics both in the gas-solid and the electrochemical reactions were distinguishably improved. (3-5) Fluorinated surface was found to function as the catalyst for a methanation reaction between the CO{sub 2} gas adsorbed over the fluorinated surface and the monatomic hydrogen absorbed in the metal lattice of the crystalline structure of the hydriding alloys. (4) A technique was developed for increasing the specific surface area and decreasing the specific surface diameter of the fluorinated hydriding alloy articles. (NEDO)

  9. Colonization by Staphylococcus aureus of Nano-Structured Fluorinated Surfaces, Formed by Different Methods of Ion-Plasma Technology.

    Science.gov (United States)

    Elinson, V M; Didenko, L V; Shevlyagina, N V; Avtandilov, G A; Gaidarova, A Kh; Lyamin, A N

    2016-11-01

    Colonization of fluorinated surfaces produced by ion-plasma technology by Staphylococcus aureus was studied by scanning electron microscopy and surface energy analysis. It was shown that the intensity of colonization was determined by the surface relief and fluorine content. Formation of nanostructured surfaces accompanied by a sharp decrease in the surface energy prevented adhesion of Staphylococcus aureus cells to the fluorine-containing surface.

  10. Salt supply to and significance of asymmetric salt diapirs

    DEFF Research Database (Denmark)

    Koyi, H.; Burliga, S.; Chemia, Zurab

    2012-01-01

    Salt diapirs can be asymmetric both internally and externally reflecting their evolution history. As such, this asymmetry bear a significant amount of information about the differential loading (± lateral forces) and in turn the salt supply that have shaped the diapir. In two dimensions...... southeastern overhang due to salt extrusion during Middle Cretaceous followed by its burial in Tertiary. This external asymmetry is also reflected in the internal configuration of the diapir which shows different rates of salt flow on the two halves of the structure. The asymmetric external and internal...... sediments, the diapir extruded an overhang. Using the asymmetric Klodawa Salt Structure (KSS) in central Poland as a prototype, a series of analogue models were carried out to investigate the evolution history and salt supply driven by asymmetric differential loading. During extension of the model, a daipir...

  11. Reversible Changes in Resistance of Perovskite Nickelate NdNiO3Thin Films Induced by Fluorine Substitution.

    Science.gov (United States)

    Onozuka, Tomoya; Chikamatsu, Akira; Katayama, Tsukasa; Hirose, Yasushi; Harayama, Isao; Sekiba, Daiichiro; Ikenaga, Eiji; Minohara, Makoto; Kumigashira, Hiroshi; Hasegawa, Tetsuya

    2017-03-29

    Perovskite nickel oxides are of fundamental as well as technological interest because they show large resistance modulation associated with phase transition as a function of the temperature and chemical composition. Here, the effects of fluorine doping in perovskite nickelate NdNiO 3 epitaxial thin films are investigated through a low-temperature reaction with polyvinylidene fluoride as the fluorine source. The fluorine content in the fluorinated NdNiO 3-x F x films is controlled with precision by varying the reaction time. The fully fluorinated film (x ≈ 1) is highly insulating and has a bandgap of 2.1 eV, in contrast to NdNiO 3 , which exhibits metallic transport properties. Hard X-ray photoelectron and soft X-ray absorption spectroscopies reveal the suppression of the density of states at the Fermi level as well as the reduction of nickel ions (valence state changes from +3 to +2) after fluorination, suggesting that the strong Coulombic repulsion in the Ni 3d orbitals associated with the fluorine substitution drives the metal-to-insulator transition. In addition, the resistivity of the fluorinated films recovers to the original value for NdNiO 3 after annealing in an oxygen atmosphere. By application of the reversible fluorination process to transition-metal oxides, the search for resistance-switching materials could be accelerated.

  12. Temporal contrast of salt delivery in mouth increases salt perception

    OpenAIRE

    Tournier, Carole; Knoop, Janine E.; Kooyman, Gonnie; Smit, Gerrit

    2009-01-01

    The impact of salt delivery in mouth on salt perception was investigated. It was hypothesized that fast concentration changes in the delivery to the receptor can reduce sensory adaptation, leading to an increased taste perception. Saltiness ratings were scored by a panel over time during various stimulation conditions involving relative changes in NaCl concentration of 20% and 38%. Changes in salt delivery profile had similar effect on saltiness perception when delivered either by a sipwise m...

  13. Relationship between salt intake as estimated by a brief self-administered diet-history questionnaire (BDHQ) and 24-h urinary salt excretion in hypertensive patients.

    Science.gov (United States)

    Sakata, Satoko; Tsuchihashi, Takuya; Oniki, Hideyuki; Tominaga, Mitsuhiro; Arakawa, Kimika; Sakaki, Minako; Kitazono, Takanari

    2015-08-01

    Assessing an individual's salt intake is necessary for providing guidance with respect to salt restriction. However, the methods that exist for assessing salt intake have both merits and limitations. Therefore, the evaluation methods should be selected for their appropriateness to the patients and the environment of the medical facilities. The purpose of the present study was to investigate the validity of a brief self-administered diet-history questionnaire (BDHQ) by comparing the responses with 24-h urinary salt excretion. A total of 136 hypertensive outpatients (54 men and 82 women) were included in this study. All subjects were given the BDHQ and performed 24-h home urine collection. The energy-adjusted salt intake as assessed by the BDHQ was 12.3 (95% confidence interval: 11.8-12.9) g per day, and the urinary salt excretion evaluated by 24-h urinary collection was 9.0 (8.4-9.5) g per day. The energy-adjusted salt intake assessed by the BDHQ correlated significantly with the urinary salt excretion evaluated by 24-h urinary collection (r=0.34, Psalt intake evaluated by the BDHQ weakly, but significantly, correlated with 24-h urinary salt excretion. In clinical practice, it seems important to utilize both methods to assess an individual's salt intake in order to provide adequate guidance for salt restriction.

  14. Polyimides Containing Fluorine and Phosphorus for Potential Space Applications

    Science.gov (United States)

    Connell, John W.; Watson, Kent A.

    2000-01-01

    As part of an effort to develop low color, ultraviolet (UV) radiation and atomic oxygen resistant polyimides for potential space applications, a novel diamine containing fluorine and phosphorus was synthesized and used to prepare polyimides. The approach was to combine attributes from colorless, UV resistant polyimides and atomic oxygen (AO) resistant polymers into a single material. Preparation of colorless polyimides has focused on minimization of charge transfer complex formation by incorporation of bulky substituents and disrupting conjugation by using meta-catenated monomers. AO resistant polymer technology development has focused on placing phenylphosphine oxide groups into the backbone of aromatic polymers. However, polyimides prepared utilizing this approach thus far have all exhibited significant color. Thus in an attempt to combine these features in a polyimide a new diamine, bis(3-aminophenyl)-3,5-di(trifluoromethyl)phenylphosphine oxide (TFMDA) was synthesized and used to prepare polyimides. The polyimides were cast into films and characterized for physical and mechanical properties, optical transmission and AO and UV resistance.

  15. Fluorine NMR-based screening on cell membrane extracts.

    Science.gov (United States)

    Veronesi, Marina; Romeo, Elisa; Lambruschini, Chiara; Piomelli, Daniele; Bandiera, Tiziano; Scarpelli, Rita; Garau, Gianpiero; Dalvit, Claudio

    2014-02-01

    The possibility of measuring the action of inhibitors of specific enzymatic reactions in intact cells, cell lysates or membrane preparations represents a major advance in the lead discovery process. Despite the relevance of assaying in physiological conditions, only a small number of biophysical techniques, often requiring complex set-up, are applicable to these sample types. Here, we demonstrate the first application of n-fluorine atoms for biochemical screening (n-FABS), a homogeneous and versatile assay based on (19) F NMR spectroscopy, to the detection of high- and low-affinity inhibitors of a membrane enzyme in cell extracts and determination of their IC50 values. Our approach can allow the discovery of novel binding fragments against targets known to be difficult to purify or where membrane-association is required for activity. These results pave the way for future applications of the methodology to these relevant and complex biological systems. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Fluorine in food with special reference to tea

    Energy Technology Data Exchange (ETDEWEB)

    Zimmerman, P.W.; Hitchcock, A.E.; Gwirtsman, J.

    A review of the literature showed that in 1932 commercial tea, Camellia sinensis Kuntze (Thea sinensis L., Camellia thea Link.), was known to contain fluorine (F). Since ornamental camellias (C. japonica L.) and tea are members of the Theaceae family, comparisons were made of the F in leaves of the two species. The dry leaves of various domestic brands of tea, composed mostly of young leaves, contained 72 to 115 parts per million (p.p.m.) F and Chinese tea 131 to 178 p.p.m. F on a dry weight basis. One sample of fresh leaves of greenhouse grown tea plants contained 1530 p.p.m. F on a dry weight basis and the older leaves of ornamental camellias up to 3062 p.p.m. F. One sample of young leaves of C. japonica contained 67 p.p.m. F. Thus both species of Camellia have the capacity to accumulate relatively large amounts of F, especially in the older leaves. The infusion (beverage) from one tea bag in 4.5 fluid oz. of water contained 0.8 to 1.7 p.p.m. F after 3 minutes steeping and 1.0 to 2.0 p.p.m. F after 3 minutes boiling.

  17. Measurement of proton inelastic scattering cross sections on fluorine

    Energy Technology Data Exchange (ETDEWEB)

    Chiari, M., E-mail: chiari@fi.infn.it [Department of Physics and Astronomy, University of Florence and INFN Florence, Sesto Fiorentino (Italy); Caciolli, A. [Department of Physics and Astronomy, University of Padua and INFN Padua, Padova (Italy); Calzolai, G. [Department of Physics and Astronomy, University of Florence and INFN Florence, Sesto Fiorentino (Italy); Climent-Font, A. [CMAM, Universidad Autonoma de Madrid, Madrid (Spain); Lucarelli, F.; Nava, S. [Department of Physics and Astronomy, University of Florence and INFN Florence, Sesto Fiorentino (Italy)

    2016-10-01

    Differential cross-sections for proton inelastic scattering on fluorine, {sup 19}F(p,p’){sup 19}F, from the first five excited levels of {sup 19}F at 110, 197, 1346, 1459 and 1554 keV were measured for beam energies from 3 to 7 MeV at a scattering angle of 150° using a LiF thin target (50 μg/cm{sup 2}) evaporated on a self-supporting C thin film (30 μg/cm{sup 2}). Absolute differential cross-sections were calculated with a method not dependent on the absolute values of collected beam charge and detector solid angle. The validity of the measured inelastic scattering cross sections was then tested by successfully reproducing EBS spectra collected from a thick Teflon (CF{sub 2}) target. As a practical application of these measured inelastic scattering cross sections in elastic backscattering spectroscopy (EBS), the feasibility of quantitative light element (C, N and O) analysis in aerosol particulate matter samples collected on Teflon by EBS measurements and spectra simulation is demonstrated.

  18. Rheology of rock salt for salt tectonics modeling

    Directory of Open Access Journals (Sweden)

    Shi-Yuan Li

    2016-10-01

    Full Text Available Abstract Numerical modeling of salt tectonics is a rapidly evolving field; however, the constitutive equations to model long-term rock salt rheology in nature still remain controversial. Firstly, we built a database about the strain rate versus the differential stress through collecting the data from salt creep experiments at a range of temperatures (20–200 °C in laboratories. The aim is to collect data about salt deformation in nature, and the flow properties can be extracted from the data in laboratory experiments. Moreover, as an important preparation for salt tectonics modeling, a numerical model based on creep experiments of rock salt was developed in order to verify the specific model using the Abaqus package. Finally, under the condition of low differential stresses, the deformation mechanism would be extrapolated and discussed according to microstructure research. Since the studies of salt deformation in nature are the reliable extrapolation of laboratory data, we simplified the rock salt rheology to dislocation creep corresponding to power law creep (n = 5 with the appropriate material parameters in the salt tectonic modeling.

  19. Reactive halogen species above salt lakes and salt pans

    OpenAIRE

    Holla, Robert

    2013-01-01

    Salt lakes can be found on all continents and saline soils cover 2.5% of the land surface of the earth (FAO, 2012). This thesis investigates the presence of reactive halogen species (RHS) above salt lakes and saline soils to evaluate their relevance for tropospheric chemistry of the planetary boundary layer. Ground-based MAX-DOAS and LP-DOAS measurements were conducted at salt lakes and two other sites with high halogen content. Prior to this work, RHS were found at three salt ...

  20. Clinical value of fluorine-18α-methyltyrosine PET in patients with gliomas: comparison with fluorine-18 fluorodeoxyglucose PET.

    Science.gov (United States)

    Horiguchi, Keishi; Tosaka, Masahiko; Higuchi, Tetsuya; Arisaka, Yukiko; Sugawara, Kenichi; Hirato, Junko; Yokoo, Hideaki; Tsushima, Yoshito; Yoshimoto, Yuhei

    2017-12-01

    We investigated the relationship between metabolic activity and histological features of gliomas using fluorine-18α-methyltyrosine (18F-FAMT) positron emission tomography (PET) compared with fluorine-18 fluorodeoxyglucose (18F-FDG) PET in 38 consecutive glioma patients. The tumor to normal brain ratios (T/N ratios) were calculated, and the relationships between T/N ratio and World Health Organization tumor grade or MIB-1 labeling index were evaluated. The diagnostic values of T/N ratios were assessed using receiver operating characteristic (ROC) curve analyses to differentiate between high-grade gliomas (HGGs) and low-grade gliomas (LGGs). Median T/N ratio of 18F-FAMT PET was 2.85, 4.65, and 4.09 for grade II, III, and IV gliomas, respectively, with significant differences between HGGs and LGGs (p = 0.006). Both T/N ratio (p = 0.016) and maximum standardized uptake value (p = 0.033) of 18F-FDG PET showed significant differences between HGGs and LGGs. ROC analysis yielded an optimal cut-off of 3.37 for the T/N ratio of 18F-FAMT PET to differentiate between HGGs and LGGs (sensitivity 81%, specificity 67%, accuracy 76%, area under the ROC curve 0.776). Positive predictive value was 84%, and negative predictive value was 62%. T/N ratio of 18F-FAMT PET was not correlated with MIB-1 labeling index in all gliomas, whereas T/N ratio of 18F-FDG PET was positively correlated (r s  = 0.400, p = 0.013). Significant positive correlation was observed between T/N ratios of 18F-FDG and 18F-FAMT (r s  = 0.454, p = 0.004), but median T/N ratio of 18F-FAMT PET was significantly higher than that of 18F-FDG PET in all grades of glioma. The T/N ratio of 18F-FAMT uptake has high positive predictive value for detection of HGGs. 18F-FAMT PET had higher T/N ratio, with better tumor-normal brain contrast, compared to 18F-FDG PET in both LGGs and HGGs. Therefore, 18F-FAMT is a useful radiotracer for the preoperative visualization of gliomas.

  1. Status of iodine content of salt in four regions of India.

    Science.gov (United States)

    Singh, Madhu B; Sharma, S K; Nair, Siri; Pandey, R M; Kapil, Umesh; Singh, Charan

    2011-06-01

    To study the Status of Iodine Content of Salt in four regions of India. At each of the four centers (Vadodara, Dibrugarh, Jodhpur, New Delhi), High Schools were selected randomly from list of schools obtained from district education office and more than 700 salt samples were selected from each center. A total of 3,010 salt samples were collected from students of High Schools (consumed at their households), selected randomly from four centers and iodine content of salt by Standard Iodometric Titration Method (IT) was estimated. Analysis revealed that majority of salt sample collected at 4 centers were of powdered variety of salt. Analysis of iodine content in salt by IT method revealed that high proportion of school children (51.6%) consumed salt having inadequate iodine content (salt samples with less than 15 ppm of iodine) in Jodhpur district followed by Vadodara (19.8%), New Delhi (8.5%) and least in Dibrugarh (1.2%). The percentage of consumption of adequately iodized salt was highest in Dibrugarh (98.8%) among the four regions of India. Status of iodine content is varying from state to state i.e. highest at Dibrugarh and lowest at Jodhpur. This indicates that consumption of iodized salt in Jodhpur is low and needs more attention. Government may adopt different strategies in different states. There is a strong need of iodization of salt in addition to creating awareness among rural inhabitants for consumption of iodized salt especially in Jodhpur District. More attention is required for monitoring quality of iodized salt available in the community.

  2. Electrolyte salts for nonaqueous electrolytes

    Science.gov (United States)

    Amine, Khalil; Zhang, Zhengcheng; Chen, Zonghai

    2012-10-09

    Metal complex salts may be used in lithium ion batteries. Such metal complex salts not only perform as an electrolyte salt in a lithium ion batteries with high solubility and conductivity, but also can act as redox shuttles that provide overcharge protection of individual cells in a battery pack and/or as electrolyte additives to provide other mechanisms to provide overcharge protection to lithium ion batteries. The metal complex salts have at least one aromatic ring. The aromatic moiety may be reversibly oxidized/reduced at a potential slightly higher than the working potential of the positive electrode in the lithium ion battery. The metal complex salts may also be known as overcharge protection salts.

  3. Salt fluoridation and oral health

    Directory of Open Access Journals (Sweden)

    Thomas M. Marthaler

    2013-11-01

    Full Text Available The aim of this paper is to make known the potential of fluoridated salt in community oral health programs, particularly in South Eastern Europe. Since 1922, the addition of iodine to salt has been successful in Switzerland. Goiter is virtually extinct. By 1945, the cariesprotective effect of fluorides was well established. Based on the success of water fluoridation, a gynecologist started adding of fluoride to salt. The sale of fluoridated salt began in 1956 in the Swiss Canton of Zurich, and several other cantons followed suit. Studies initiated in the early seventies showed that fluoride, when added to salt, inhibits dental caries. The addition of fluoride to salt for human consumption was officially authorized in 1980-82. In Switzerland 85% of domestic salt consumed is fluoridated and 67% in Germany. Salt fluoridation schemes are reaching more than one hundred million in Mexico, Colombia, Peru and Cuba. The cost of salt fluoridation is very low, within 0.02 and 0.05 € per year and capita. Children and adults of the low socio-economic strata tend to have substantially more untreated caries than higher strata. Salt fluoridation is by far the cheapest method for improving oral health. Conclusions. Salt fluoridation has cariostatic potential like water fluoridation (caries reductions up to 50%. In Europe, meaningful percentages of users have been attained only in Germany (67% and Switzerland (85%. In Latin America, there are more than 100 million users, and several countries have arrived at coverage of 90 to 99%. Salt fluoridation is by far the cheapest method of caries prevention, and billions of people throughout the world could benefit from this method.

  4. Dietary Salt Intake and Hypertension

    Science.gov (United States)

    2014-01-01

    Over the past century, salt has been the subject of intense scientific research related to blood pressure elevation and cardiovascular mortalities. Moderate reduction of dietary salt intake is generally an effective measure to reduce blood pressure. However, recently some in the academic society and lay media dispute the benefits of salt restriction, pointing to inconsistent outcomes noted in some observational studies. A reduction in dietary salt from the current intake of 9-12 g/day to the recommended level of less than 5-6 g/day will have major beneficial effects on cardiovascular health along with major healthcare cost savings around the world. The World Health Organization (WHO) strongly recommended to reduce dietary salt intake as one of the top priority actions to tackle the global non-communicable disease crisis and has urged member nations to take action to reduce population wide dietary salt intake to decrease the number of deaths from hypertension, cardiovascular disease and stroke. However, some scientists still advocate the possibility of increased risk of CVD morbidity and mortality at extremes of low salt intake. Future research may inform the optimal sodium reduction strategies and intake targets for general populations. Until then, we have to continue to build consensus around the greatest benefits of salt reduction for CVD prevention, and dietary salt intake reduction strategies must remain at the top of the public health agenda. PMID:25061468

  5. Influence of Backbone Fluorination in Regioregular Poly(3-alkyl-4-fluoro)thiophenes

    KAUST Repository

    Fei, Zhuping

    2015-06-03

    © 2015 American Chemical Society. We report two strategies toward the synthesis of 3-alkyl-4-fluorothiophenes containing straight (hexyl and octyl) and branched (2-ethylhexyl) alkyl groups. We demonstrate that treatment of the dibrominated monomer with 1 equiv of alkyl Grignard reagent leads to the formation of a single regioisomer as a result of the pronounced directing effect of the fluorine group. Polymerization of the resulting species affords highly regioregular poly(3-alkyl-4-fluoro)thiophenes. Comparison of their properties to those of the analogous non-fluorinated polymers shows that backbone fluorination leads to an increase in the polymer ionization potential without a significant change in optical band gap. Fluorination also results in an enhanced tendency to aggregate in solution, which is ascribed to a more co-planar backbone on the basis of Raman and DFT calculations. Average charge carrier mobilities in field-effect transistors are found to increase by up to a factor of 5 for the fluorinated polymers.

  6. Theoretical Assessment of Fluorinated Phospholipids in the Design of Liposomal Drug-Delivery Systems.

    Science.gov (United States)

    Madsen, Jesper J; Fristrup, Peter; Peters, Günther H

    2016-09-15

    Fluorinated phospholipid analogues are investigated as potential substrates for phospholipase A2 (PLA2) using classical molecular dynamics simulations and quantum mechanics/density functional theory calculations. The fluorinated phospholipid analogues are α-fluoro (HF-ProAEL) and α,α-difluoro (F2-ProAEL) conjugates of (R)-1-O-hexadecyl-2-palmitoyl-sn-glycero-3-phoshocholineglycerol (ProAEL). Our results provide a theoretical assessment of the potential usefulness of these fluorinated lipids in the rational design of liposomal drug-delivery systems. The α-fluorine-substituted phospholipid analogues are found to be substrates for secretory PLA2, with sufficient accessibility of water to the active site to allow for enzymatic hydrolysis. Because of the inherently less stable nature of HF-ProAEL and F2-ProAEL when compared to that of ProAEL, the hydrolytic reaction is predicted to occur at a progressively faster rate; the more electronegative substituent at the α-position effectively lowers the energy barrier for hydrolysis. We conclude that the partially fluorinated phospholipid analogues facilitate rational design of liposomal vesicles of phospholipid mixtures with desirable physicochemical properties and that are still subjects for important and pharmaceutically proven drug-delivery mechanisms.

  7. Content and distribution of fluorine in rock, clay and water in fluorosis area Zhaotong, Yunnan Province

    Energy Technology Data Exchange (ETDEWEB)

    Luo, K.; Li, H.; Feng, F. (and others) [Chinese Academy of Sciences, Beijing (China)

    2007-04-15

    About 160 samples of coal, pyritic coal balls, coal seam gangue, clay, corn, capsicum and drinking water were collected from the endemic fluorosis area of Zhenxiong and Weixin county, China to determine the fluorine content, distribution pattern and source in this fluorosis area. The study shows that the average fluorine content in the coal samples collected from 3 coal mines of the Late Permian coals in Zhenxiong and Weixin county, Zhaotong City, which are the main mining coals there, is 77.13 mg/kg. The average fluorine content coals collected form thee typical fluorosis villages in 72.56 mg/kg. Both of them are close to the world average and little low than the Chinese average. The fluorine content of drinking water is lower than 0.35 mg/L, the clay used as an additive for coal-burning and as a binfer in briquette-making by local residents has a high content of fluorine, ranging from 367-2,435 mg/kg, with the majority higher than 600 mg/kg and an average of 1,084.2 mg/kg. 29 refs., 5 tabs.

  8. Development of the titanium–TADDOLate-catalyzed asymmetric fluorination of β-ketoesters

    Directory of Open Access Journals (Sweden)

    Lukas Hintermann

    2011-10-01

    Full Text Available Titanium-based Lewis acids catalyze the α-fluorination of β-ketoesters by electrophilic N–F-fluorinating reagents. Asymmetric catalysis with TADDOLato–titanium(IV dichloride (TADDOL = α,α,α',α'-tetraaryl-(1,3-dioxolane-4,5-diyl-dimethanol Lewis acids produces enantiomerically enriched α-fluorinated β-ketoesters in up to 91% enantiomeric excess, with either F–TEDA (1-chloromethyl-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate in acetonitrile solution or NFSI (N-fluorobenzenesulfonimide in dichloromethane solution as fluorinating reagents. The effects of various reaction parameters and of the TADDOL ligand structure on the catalytic activity and enantioselectivity were investigated. The absolute configuration of several fluorination products was assigned through correlation. Evidence for ionization of the catalyst complex by chloride dissociation, followed by generation of titanium β-ketoenolates as key reaction intermediates, was obtained. Based on the experimental findings, a general mechanistic sketch and a steric model of induction are proposed.

  9. Fluorine in the Solar Neighborhood: Is It All Produced in Asymptotic Giant Branch Stars?

    Science.gov (United States)

    Jönsson, H.; Ryde, N.; Harper, G. M.; Richter, M. J.; Hinkle, K. H.

    2014-07-01

    The origin of "cosmic" fluorine is uncertain, but there are three proposed production sites/mechanisms for the origin: asymptotic giant branch (AGB) stars, ν nucleosynthesis in Type II supernovae, and/or the winds of Wolf-Rayet stars. The relative importance of these production sites has not been established even for the solar neighborhood, leading to uncertainties in stellar evolution models of these stars as well as uncertainties in the chemical evolution models of stellar populations. We determine the fluorine and oxygen abundances in seven bright, nearby giants with well determined stellar parameters. We use the 2.3 μm vibrational-rotational HF line and explore a pure rotational HF line at 12.2 μm. The latter has never been used before for an abundance analysis. To be able to do this, we have calculated a line list for pure rotational HF lines. We find that the abundances derived from the two diagnostics agree. Our derived abundances are well reproduced by chemical evolution models including only fluorine production in AGB stars and, therefore, we draw the conclusion that this might be the main production site of fluorine in the solar neighborhood. Furthermore, we highlight the advantages of using the 12 μm HF lines to determine the possible contribution of the ν process to the fluorine budget at low metallicities where the difference between models including and excluding this process is dramatic.

  10. Relationship Between Salt Intake, Salt-Taste Threshold and Blood ...

    African Journals Online (AJOL)

    Background: Many studies have found an association between sodium intake and blood pressure. Salt taste threshold is thought to be another marker of sodium intake. Objective: This study sought to assess two markers of sodium intake, 24-hour-urinary sodium and salt-taste threshold. We also determined the relationship ...

  11. Temporal contrast of salt delivery in mouth increases salt perception

    NARCIS (Netherlands)

    Busch, J.L.H.C.; Tournier, C.; Knoop, J.E.; Kooyman, G.; Smit, G.

    2009-01-01

    The impact of salt delivery in mouth on salt perception was investigated. It was hypothesized that fast concentration changes in the delivery to the receptor can reduce sensory adaptation, leading to an increased taste perception. Saltiness ratings were scored by a panel over time during various

  12. Heat Transfer Salts for Nuclear Reactor Systems - Chemistry Control, Corrosion Mitigation, and Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Mark [Univ. of Wisconsin, Madison, WI (United States); Sridharan, Kumar [Univ. of Wisconsin, Madison, WI (United States); Morgan, Dane [Univ. of Wisconsin, Madison, WI (United States); Peterson, Per [Univ. of Wisconsin, Madison, WI (United States); Calderoni, Pattrick [Univ. of Wisconsin, Madison, WI (United States); Scheele, Randall [Univ. of Wisconsin, Madison, WI (United States); Casekka, Andrew [Univ. of Wisconsin, Madison, WI (United States); McNamara, Bruce [Univ. of Wisconsin, Madison, WI (United States)

    2015-01-22

    -evaluate thermophysical properties of flibe and flinak. Pacific Northwest National Laboratories has focused on evaluating the fluorinating gas nitrogen trifluoride as a potential salt purification agent. Work there was performed on removing hydroxides and oxides from flinak salt under controlled conditions. Lastly, the University of California Berkeley has spent considerable time designing and simulating reactor components with fluoride salts at high temperatures. Despite the hurdles presented by the innate chemical hazards, considerable progress has been made. The stage has been set to perform new research on salt chemical control which could advance the fluoride salt cooled reactor concept towards commercialization. What were previously thought of as chemical undesirable, but nuclear certified, alloys have been shown to be theoretically compatible with fluoride salts at high temperatures. This preliminary report has been prepared to communicate the construction of the basic infrastructure required for flibe, as well as suggest original research to performed at the University of Wisconsin. Simultaneously, the contents of this report can serve as a detailed, but introductory guide to allow anyone to learn the fundamentals of chemistry, engineering, and safety required to work with flibe salt.

  13. Experiments in connection with Salt Domes

    NARCIS (Netherlands)

    Escher, B.G.; Kuenen, Ph.H.

    1928-01-01

    The different theories concerning the origin of Salt Domes in Roumania, Germany, Texas, Louisiana, Colorado and Utah are discussed. In Roumania the salt occurs in cores of “Diapir” anticlines. The existance of hills of salt indicates, that the salt is still pushing upwards. In Germany the salt

  14. Sodium: How to Tame Your Salt Habit

    Science.gov (United States)

    ... same amount of sodium as table salt. Use salt substitutes wisely. Some salt substitutes or light salts contain a mixture of table ... substitute — and get too much sodium. Also, many salt substitutes contain potassium chloride. Although potassium can lessen some ...

  15. Proton conducting sulphonated fluorinated poly(styrene) crosslinked electrolyte membranes

    Energy Technology Data Exchange (ETDEWEB)

    Soules, A.; Ameduri, B.; Boutevin, B.; David, G. [Institut Charles Gerhardt UMR CNRS 5253 Equipe, Ingenierie et Architectures Macromoleculaires,' ' Ecole Nationale Superieure de Chimie de Montpellier, 8 rue de l' Ecole Normale, 34296 Montpellier, Cedex 05 (France); Perrin, R. [CEA Le Ripault Departement des Materiaux, DMAT/SCMF/LSTP, BP16 - 37260 Monts (France); Gebel, G. [Structure et Proprietes des Architectures Moleculaires UMR 5819 (CEA-CNRS-UJF), INAC, SPrAM, CEA Grenoble, 17 Rue des Martyrs, 38054 Grenoble, Cedex 9 (France)

    2011-10-15

    Potential membranes for polymer electrolyte membrane fuel cell based on crosslinked sulphonated fluorinated polystyrenes (PS) were synthesised in two steps. First, azide-telechelic polystyrene was obtained by iodine transfer polymerisation of styrene in the presence of 1,6-diiodoperfluorohexane followed by azido chain-end functionalisation. Then azide-telechelic polystyrene was efficiently crosslinked with 1,10-diazido-1H,1H,2H,2H,9H,9H,10H,10H-perfluorodecane under UV irradiation. After 45 min only, almost completion of azide crosslinking could be achieved, resulting in crosslinked membranes with insoluble fractions higher than 95%. The sulphonation of the crosslinked membranes afforded ionic exchange capacities (IECs) ranging from 2.2 to 3.2 meq g{sup -1}. The hydration number was shown to be very high (from 30 to 75), depending on both the content of perfluorodecane and of sulphonic acid groups. The morphology of the membranes, assessed by small-angle X-ray scattering, was found to be a lamellar-type structure with two types of ionic domains. For the membrane that exhibited an IEC value of 2.2 meq.g{sup -1}, proton conductivity was in the same range as that of Nafion {sup registered} (120-135 mS.cm{sup -1}), whereas the membrane IEC value of 3.2 meq.g{sup -1} showed a proton conductivity higher than that of Nafion {sup registered} in liquid water from 25 to 80 C, though a high water uptake. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Detection of anaerobic odontogenic infections by fluorine-18 fluoromisonidazole

    Energy Technology Data Exchange (ETDEWEB)

    Liu Renshyan [National PET/Cyclotron Center and Dept. of Nuclear Medicine, Taipei Veterans General Hospital, National Yang-Ming Univ. Medical School, Taipei (Taiwan, Province of China); Chu Leeshing [National PET/Cyclotron Center and Dept. of Nuclear Medicine, Taipei Veterans General Hospital, National Yang-Ming Univ. Medical School, Taipei (Taiwan, Province of China)]|[National Defense Medical Center, Taipei (Taiwan); Yen Sanhui [National PET/Cyclotron Center and Dept. of Nuclear Medicine, Taipei Veterans General Hospital, National Yang-Ming Univ. Medical School, Taipei (Taiwan, Province of China)]|[National Defense Medical Center, Taipei (Taiwan); Chang Chenpei [National PET/Cyclotron Center and Dept. of Nuclear Medicine, Taipei Veterans General Hospital, National Yang-Ming Univ. Medical School, Taipei (Taiwan, Province of China); Chou Kuoliang [National PET/Cyclotron Center and Dept. of Nuclear Medicine, Taipei Veterans General Hospital, National Yang-Ming Univ. Medical School, Taipei (Taiwan, Province of China); Wu Liangchi [National PET/Cyclotron Center and Dept. of Nuclear Medicine, Taipei Veterans General Hospital, National Yang-Ming Univ. Medical School, Taipei (Taiwan, Province of China); Chang Chiwei [National PET/Cyclotron Center and Dept. of Nuclear Medicine, Taipei Veterans General Hospital, National Yang-Ming Univ. Medical School, Taipei (Taiwan, Province of China); Lui Muntain [Dept. of Dentistry, Taipei Veterans General Hospital (Taiwan, Province of China); Chen Kuangy [National PET/Cyclotron Center and Dept. of Nuclear Medicine, Taipei Veterans General Hospital, National Yang-Ming Univ. Medical School, Taipei (Taiwan, Province of China)]|[National Defense Medical Center, Taipei (Taiwan); Yeh Shinhwa [National PET/Cyclotron Center and Dept. of Nuclear Medicine, Taipei Veterans General Hospital, National Yang-Ming Univ. Medical School, Taipei (Taiwan, Province of China)

    1996-10-01

    Odontogenic infections are a potential risk for patients who receive cervicofacial radiotherapy and should be treated before irradiation. Anaerobic microbial infections are the most common causes. This study assessed the value of the hypoxic imaging agent fluorine-18 fluoromisonidazole (FMISO) in detecting anaerobic odontogenic infections. Positron emission tomography (PET) imaging was performed at 2 h after injection of 370 MBq (10 mCi) of FMISO in 26 nasopharyngeal carcinoma patients and six controls with healthy teeth. Tomograms were interpreted visually to identify hypoxic foci in the jaw. All patients received thorough dental examinations as a pre-radiotherapy work-up. Fifty-one sites of periodonititis, 15 periodontal abscesses, 14 sites of dental caries with root canal infection, 23 sites of dental caries without root canal infection, and seven necrotic pulps were found by dental examination. Anaerobic pathogens were isolated from 12 patients. Increased uptake of FMISO was found at 45 out of 51 sites of periodontitis, all 15 sites of periodontal abscess, all 14 sites of dental caries with root canal infection, all seven sites of necrotic pulp and 15 sites of dental carries without obvious evidence of active root canal infection. No abnormal uptake was seen in the healthy teeth of patients or in the six controls. The diagnostic sensitivity, specificity, positive and negative predictive values, and accuracy of FMISO PET scan in detecting odontogenic infections were 93%, 97%, 84%, 99% and 96%, respectively. {sup 18}F-fluoride ion bone scan done in three patients showed that {sup 18}F-fluoride ion plays no role in the demonstration of anaerobic odontogenic infection. FMISO PET scan is a sensitive method for the detection of anaerobic odontogenic infections, and may play a complementary role in the evaluation of the dental condition of patients with head and neck tumours prior to radiation therapy. (orig.)

  17. Fluorine in silicate glasses: A multinuclear nuclear magnetic resonance study

    Energy Technology Data Exchange (ETDEWEB)

    Schaller, T.; Dingwell, D.B.; Keppler, H.; Merwin, L.; Sebald, A. (Univ. Bayreuth (West Germany)); Knoeller, W. (Bruker Analytische Messtechnik, Rheinstetten (West Germany))

    1992-02-01

    Anhydrous nepheline, jadeite, and albite glasses doped with F as well as hydrous F-containing haplogranitic glasses were investigated using {sup 19}F combined rotation and multiple-pulse spectroscopy; {sup 19}F {yields} {sup 29}Si cross-polarization/magic angle spinning (MAS); and high-power {sup 19}F decoupled {sup 29}Si, {sup 23}Na, and {sup 27}Al MAS nuclear magnetic resonance methods. Fluorine preferentially coordinates with Al to form octahedral AlF{sub 6}{sup 3{minus}} complexes in all glasses studied. In addition, F anions bridging two Al cations, units containing octahedral Al coordinated by both O and F, or tetrahedral Al-F complexes might be present. The presence of Si-F bonds cannot be entirely ruled out but appears unlikely on the basis of the {sup 19}F {yields} {sup 29}Si CP/MAS spectra. There is no evidence for any significant coordination of F with alkalis in the glasses studied. Over the range of F contents studied (up to 5 wt.%), there seems to be hardly any dependence of F speciation on the concentration of F in the samples. The spectroscopic results explain the decrease of the viscosity of silicate melts with increasing F content by removal of Al from bridging AlO{sub 4}-units due to complexing with F, which causes depolymerization of the melt. The same mechanism can account for the shift of the eutectic point in the haplogranite system to more feldspar-rich compositions with increasing F content, and for the peraluminous composition of most F-rich granites. Liquid immiscibility in F-rich granitic melts might be caused by formation of (Na,K){sub 3}AlF{sub 6} units in the melt with little or no interaction with the silicate component. The presence of F in granitic melts might increase the solubility of high field strength cations by making nonbridging O atoms available which form complexes with these cations.

  18. Electrochemical synthesis of fluorine from 1886 to 2006: fluorine, a key-element for nuclear energy; Le fluor, element cle pour l'energie nucleaire. Synthese electrochimique du fluor de 1886 a 2006

    Energy Technology Data Exchange (ETDEWEB)

    Groult, H.; Lantelme, F.; Devilliers, D. [Universite Pierre et Marie Curie, Lab. LI2C, CNRS UMR 7612, 75 - Paris (France); Belhomme, C.; Morel, B. [Areva/Comurhex, Lab. R et D, 26 - Pierrelatte (France); Nicolas, F. [Buc Areva NC, 26 - Pierrelatte (France); Caire, J.P. [Ecole Nationale Superieure d' Electrochimie et d' Electrometallurgie de Grenoble, LEPMI, 38 - Saint Martin d' Heres (France)

    2006-10-15

    The preparation of fluorine gas by electrolysis of molten fluorides by Henri Moissan was one of the most important discoveries in chemistry during the last century. Indeed, in addition to its use in many industrial fields (microelectronic, surface cleaning, pharmacology, medicine...), fluorine gas is involved in the development of nuclear energy since it is directly used for the preparation of UF{sub 6}, the process gas for isotopic enrichment of uranium. Due to the increase of the energy demand in industrialized and emergent countries, the production of UF{sub 6} and thus of fluorine is bound to increase significantly during the next decades. The aim of this paper is to present the process which has been used to produce fluorine from the origin to the present. The use of fluorine in the nuclear field will be also discussed. (authors)

  19. COMPARISON OF GEO-MECHANICAL PROPERTIES OF WHITE ROCK SALT AND PINK ROCK SALT IN KŁODAWA SALT DIAPIR

    National Research Council Canada - National Science Library

    Malwina Kolano; Danuta Flisiak

    2013-01-01

    .... The present article introduces strength-strain properties of white rock salt, building the nucleus of northeastern edge anticline, and pink rock salt that belongs to the series of youngest rock salt...

  20. Optimization of localized 19F magnetic resonance spectroscopy for the detection of fluorinated drugs in the human liver

    NARCIS (Netherlands)

    Klomp, Dennis W. J.; van Laarhoven, Hanneke W. M.; Kentgens, Arno P. M.; Heerschap, Arend

    2003-01-01

    Fluorine MR spectroscopy ((19)F MRS) is an indispensable tool for assessing the pharmacokinetics of fluorinated drugs. Since the metabolism of 5-fluorouracil (5FU), a frequently used cytotoxic drug, is expected to be different in normal liver and in tumor tissue, spatial localization is required for

  1. Optimization of localized 19F magnetic resonance spectroscopy for the detection of fluorinated drugs in the human liver.

    NARCIS (Netherlands)

    Klomp, D.W.J.; Laarhoven, H.W.M. van; Kentgens, A.P.M.; Heerschap, A.

    2003-01-01

    Fluorine MR spectroscopy ((19)F MRS) is an indispensable tool for assessing the pharmacokinetics of fluorinated drugs. Since the metabolism of 5-fluorouracil (5FU), a frequently used cytotoxic drug, is expected to be different in normal liver and in tumor tissue, spatial localization is required for

  2. A fluorine-mediated hydrothermal method to synthesize mesoporous rhombic ZnO nanorod arrays and their gas sensor application.

    Science.gov (United States)

    Wen, Zhen; Zhu, Liping; Li, Lei; Sun, Luwei; Cai, Hui; Ye, Zhizhen

    2013-11-28

    A facile fluorine-mediated hydrothermal method was developed to synthesize mesoporous rhombic ZnO nanorod arrays. Fluorine ions play an essential role in the growth process. The novel ZnO nanorod array based gas sensor showed high performance for ethanol detection.

  3. Enhancement of the Stability of Fluorine Atoms on Defective Graphene and at Graphene/Fluorographene Interface.

    Science.gov (United States)

    Ao, Zhimin; Jiang, Quanguo; Li, Shuang; Liu, Hao; Peeters, Francois M; Li, Sean; Wang, Guoxiu

    2015-09-09

    Fluorinated graphene is one of the most important derivatives of graphene and has been found to have great potential in optoelectronic and photonic nanodevices. However, the stability of F atoms on fluorinated graphene under different conditions, which is essential to maintain the desired properties of fluorinated graphene, is still unclear. In this work, we investigate the diffusion of F atoms on pristine graphene, graphene with defects, and at graphene/fluorographene interfaces by using density functional theory calculations. We find that an isolated F atom diffuses easily on graphene, but those F atoms can be localized by inducing vacancies or absorbates in graphene and by creating graphene/fluorographene interfaces, which would strengthen the binding energy of F atoms on graphene and increase the diffusion energy barrier of F atoms remarkably.

  4. Observation of Individual Fluorine Atom from Highly Oriented Poly (tetrafluoroethylene) Films by Atomic Force Microscopy

    Science.gov (United States)

    Lee, Jonathan A.,; Paley, Mark S.

    1999-01-01

    Direct observation of the film thickness, molecular structure and individual fluorine atoms from highly oriented poly(tetrafluoroethylene) (PTFE) films were achieved using atomic force microscopy (AFM). A thin PTFE film is mechanically deposited onto a smooth glass substrate at specific temperatures by a friction transfer technique. Atomic resolution images of these films show that the chain-like helical structures of the PTFE macromolecules are aligned parallel to each other with an intermolecular spacing of 5.72 A, and individual fluorine atoms are clearly observed along these twisted molecular chains with an interatomic spacing of 2.75 A. Furthermore, the first direct AFM measurements for the radius of the fluorine-helix, and of the carbon-helix in sub-angstrom scale are reported as 1.70 A and 0.54 A respectively.

  5. Observation of Individual Fluorine Atoms from Highly Oriented Poly(Tetrafluoroethylene) Films by Atomic Force Microscopy

    Science.gov (United States)

    Lee, J. A.

    2000-01-01

    Direct observation of the film thickness, molecular structure, and individual fluorine atoms from highly oriented poly(tetrafluoroethylene) (PTFE) films were achieved using atomic force microscopy (AFM). A thin PTFE film is mechanically deposited onto a smooth glass substrate at specific temperatures by a friction-transfer technique. Atomic resolution images of these films show that the chain-like helical structures of the PTFE macromolecules are aligned parallel to each other with an intermolecular spacing of 5.72 A, and individual fluorine atoms are clearly observed along these twisted molecular chains with an interatomic spacing of 2.75 A. Furthermore, the first direct AFM measurements for the radius of the fluorine-helix, and of the carbon-helix in sub-angstrom scale are reported as 1.7 and 0.54 A respectively.

  6. Enhanced lifetime in porous silicon light-emitting diodes with fluorine doped tin oxide electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Macedo, Andreia G. [Departamento de Fisica, Universidade Federal do Parana, 81531-990, Curitiba-PR (Brazil); Vasconcelos, Elder A. de [Departamento de Fisica, Universidade Federal de Pernambuco, Cidade Universitaria, 50670-901 Recife-PE (Brazil); Valaski, Rogerio [Flexitec Eletronica Organica Ltda, 81531-990 Curitiba-PR (Brazil); Muchenski, Fabio [Departamento de Fisica, Universidade Federal do Parana, 81531-990, Curitiba-PR (Brazil); Silva, Eronides F. da [Departamento de Fisica, Universidade Federal de Pernambuco, Cidade Universitaria, 50670-901 Recife-PE (Brazil); Silva, Antonio F. da [Instituto de Fisica, Universidade Federal da Bahia, Campus Ondina, 40210-340, Salvador-BA (Brazil); Roman, Lucimara S. [Departamento de Fisica, Universidade Federal do Parana, 81531-990, Curitiba-PR (Brazil)], E-mail: lsroman@fisica.ufpr.br

    2008-11-28

    We investigated the electrical and optical properties of porous Si (PS) light-emitting diodes using fluorinated tin oxide (FTO) as transparent electrodes. At high forward bias, the current-voltage characteristic is space charge limited. At low forward bias, it follows an exponential law. Whereas the electroluminescence (EL) in devices with non-fluorinated indium-tin oxide electrodes degrades in few minutes, EL intensity in devices with FTO electrodes shows little degradation after 1300 min of operation. This result indicates that the well known beneficial effects of fluorinated species in the improvement of resistance to irradiation and carrier injection degradation in metal-oxide-semiconductor devices might be also observed in PS devices.

  7. Theoretical Rocket Performance of JP-4 Fuel with Several Fluorine-Oxygen Mixtures Assuming Equilibrium Composition

    Science.gov (United States)

    Gordon, Sanford

    1958-01-01

    Theoretical rocket performance for equilibrium composition during expansion was calculated for JP-4 fuel with several fluorine-oxygen mixtures for a range of pressure ratios and oxidant-fuel ratios. The parameters included are specific impulse, combustion-chamber temperature, nozzle-exit temperature, molecular weight, characteristic velocity, coefficient of thrust, ratio of nozzle-exit area to throat area, specific heat at constant pressure, isentropic exponent, viscosity, thermal conductivity, and equilibrium gas compositions. A correlation is given for the effect of chamber pressure on several of the parameters. The maximum value of specific impulse for a chamber pressure of 600 pounds per square inch absolute (40.827 atm) and an exit pressure of 1 atmosphere is 325.7 for 70.37 percent fluorine in the oxidant as compared with 284.9 and 305.1 for 100 percent oxygen and 100 percent fluorine, respectively.

  8. Fluorine Bonding Enhances the Energetics of Protein-Lipid Binding in the Gas Phase

    Science.gov (United States)

    Liu, Lan; Jalili, Nobar; Baergen, Alyson; Ng, Simon; Bailey, Justin; Derda, Ratmir; Klassen, John S.

    2014-05-01

    This paper reports on the first experimental study of the energies of noncovalent fluorine bonding in a protein-ligand complex in the absence of solvent. Arrhenius parameters were measured for the dissociation of gaseous deprotonated ions of complexes of bovine β-lactoglobulin (Lg), a model lipid-binding protein, and four fluorinated analogs of stearic acid (SA), which contained (X =) 13, 15, 17, or 21 fluorine atoms. In all cases, the activation energies (Ea) measured for the loss of neutral XF-SA from the (Lg + XF-SA)7- ions are larger than for SA. From the kinetic data, the average contribution of each > CF2 group to Ea was found to be ~1.1 kcal mol-1, which is larger than the ~0.8 kcal mol-1 value reported for > CH2 groups. Based on these results, it is proposed that fluorocarbon-protein interactions are inherently stronger (enthalpically) than the corresponding hydrocarbon interactions.

  9. Experimental study of the plasma fluorination of Y-Ba-Cu-O thin films

    CERN Document Server

    Li Qi; Ji Zheng Ming; Feng Yi Jun; Kang Lin; Yang Sen Zu; Wu Pei Heng; Wang Xiao Shu; Ye Yuda

    2002-01-01

    The authors have experimentally studied the surface modifications of Y-Ba-Cu-O (YBCO) thin films using CF sub 4 plasma. The intensity of the plasma fluorination was controlled by changing the biasing voltage and the time of the plasma treatment. Microstructural analyses reveal that the oxygen content of the YBCO thin films was changed. Transport measurements of sufficient fluorinated YBCO films imply that the films changed totally into an oxygen-deficient semi-conducting state. From these experimental results, the authors believe that plasma fluorination is quite a useful method to form controllable a thin barrier layer in fabricating interface engineered junctions and to form a stable narrow weak-link region in fabricating planar superconductor-normal-superconductor junctions

  10. Synthesis and texturization processes of (super)-hydrophobic fluorinated surfaces by atmospheric plasma

    CERN Document Server

    Hubert, Julie; Dufour, Thierry; Vandencasteele, Nicolas; Reniers, François; Viville, Pascal; Lazzaroni, Roberto; Raes, M; Terryn, Herman

    2016-01-01

    The synthesis and texturization processes of fluorinated surfaces by means of atmospheric plasma are investigated and presented through an integrated study of both the plasma phase and the resulting material surface. Three methods enhancing the surface hydrophobicity up to the production of super-hydrophobic surfaces are evaluated: (i) the modification of a polytetrafluoroethylene (PTFE) surface, (ii) the plasma deposition of fluorinated coatings and (iii) the incorporation of nanoparticles into those fluorinated films. In all the approaches, the nature of the plasma gas appears to be a crucial parameter for the desired property. Although a higher etching of the PTFE surface can be obtained with a pure helium plasma, the texturization can only be created if O2 is added to the plasma, which simultaneously decreases the total etching. The deposition of CxFy films by a dielectric barrier discharge leads to hydrophobic coatings with water contact angles (WCAs) of 115{\\textdegree}, but only the filamentary argon d...

  11. Caenorhabditis elegans response to salt

    NARCIS (Netherlands)

    O.O. Umuerri (Oluwatoroti Omowayewa)

    2012-01-01

    textabstractThis thesis describes my work, where I used genetic methods to identify new genes involved in salt taste in C. elegans. In addition, I used calcium imaging to characterize the cellular response of C. elegans to salt. The thesis is divided into five sections and each section is summarized

  12. Bile salts secretion in cirrhosis.

    Science.gov (United States)

    Correia, J P; Areias, E; Meneses, L; Tiago, E

    1977-02-01

    The bile salts secretion was studied in ten normal subjects and sixteen patients with alcoholic cirrhosis, in a basal period and during 60 minutes after Secretin injection. Total bile salts were measured by a modification of the enzymatic method of Iwata and Yamasaki and the individual bile salts were separated by silica gel thin-layer chromatography. During the 60 minutes after Secretin the mean concentration was 2.88 +/- 2.58 muM/ml in normals and 1.96 +/- 1.25 muM/ml in cirrhotics. The difference is not significant. During the first 20 minutes however the concentration was higher than 3 muM/ml in 8 out of 10 normals and lower than 2 muM/ml in 10 out 16 cirrhotics. The ratios of tri-to dihydroxy bile salts was similar in both groups. The ratios between bile salts conjugated with glycine and with taurine was higher in normals, and the ratio between free to conjugated bile salts was higher in cirrhotics. The lower concentration of total bile salts immediatly after Secretin, the higher proportion of taurin conjugates and of free bile salts could be important factors in the difficulties of fact digestion and absorption frequently found in patients with alcoholic cirrhosis.

  13. Compressibility of granulated rock salt

    Energy Technology Data Exchange (ETDEWEB)

    Stinebaugh, R.E.

    1979-08-01

    Crushed rock salt will be used extensively at the Waste Isolation Pilot Plant as a material for backfilling underground openings. This document addresses one of the characteristics of crushed salt which must be known to assess the consequences of its usage, namely, compressibility.

  14. Microstructure, mechanical, and in vitro properties of mica glass-ceramics with varying fluorine content.

    Science.gov (United States)

    Molla, Atiar Rahaman; Basu, Bikramjit

    2009-04-01

    The design and development of glass ceramic materials provide us the unique opportunity to study the microstructure development with changes in either base glass composition or heat treatment conditions as well as to understand processing-microstructure-property (mechanical/biological) relationship. In the present work, it is demonstrated how various crystal morphology can develop when F(-) content in base glass (K(2)O-B(2)O(3)-Al(2)O(3)-SiO(2)-MgO-F) is varied in the range of 1.08-3.85% and when all are heat treated at varying temperatures of 1000-1120 degrees C. For some selected heat treatment temperature, the heat treatment time is also varied over 4-24 h. It was established that with increase in fluoride content in the glass composition, the crystal volume fraction of the glass-ceramic decreases. Using 1.08% fluoride, more than 80% crystal volume fraction could be achieved in the K(2)O-B(2)O(3)-Al(2)O(3)-SiO(2)-MgO-F system. It was observed that with lower fluoride content glass-ceramic, if heated at 1040 degrees C for 12 h, an oriented microstructure with 'envelop like' crystals can develop. For glass ceramics with higher fluorine content (2.83% or 3.85%), hexagonal-shaped crystals are formed. Importantly, high hardness of around 8 GPa has been measured in glass ceramics with maximum amount of crystals. The three-point flexural strength and elastic modulus of the glass-ceramic (heat treated at 1040 degrees C for 24 h) was 80 MPa and 69 GPa of the sample containing 3.85% fluorine, whereas, similar properties obtained for the sample containing 1.08% F(-) was 94 MPa and 57 GPa, respectively. Further, in vitro dissolution study of the all three glass-ceramic composition in artificial saliva (AS) revealed that leached fluoride ion concentration was 0.44 ppm, when the samples were immersed in AS for 8 weeks. This was much lower than the WHO recommended safety limits of 1.5 ppm. Among all the investigated glass-ceramic samples, the glass ceramic with 3.85% F

  15. DPA-714, a new translocator protein-specific ligand: Synthesis, radio-fluorination, and pharmacologic characterization

    Energy Technology Data Exchange (ETDEWEB)

    James, M. [Univ Sydney, Dept Pharmacol, Sydney, NSW 2006 (Australia); Fulton, R.R.; Henderson, D.J. [Royal Prince Alfred Hosp, Dept PET and Nucl Med, Camperdown, NSW 2050 (Australia); Vercoullie, J.; Garreau, L.; Chalon, S. [INSERM, U619, Tours (France); Dolle, F. [Inst Imagerie Biomed, Serv Hosp Frederic Joliot, CEA, Orsay (France); Selleri, S. [Univ Florence, Dipartimento Sci Farmaceut, I-50121 Florence (Italy); Kassiou, M. [Univ Sydney, Brain and Mind Res Inst, Camperdown, NSW 2050 (Australia); Kassiou, M. [Univ Sydney, Discipline Med Radiat Sci, Sydney, NSW 2006 (Australia); Kassiou, M. [Univ Sydney, Sch Chem, Camperdown, NSW 2050 (Australia)

    2008-07-01

    The translocator protein (18 kDa) (TSPO), formerly known as the peripheral benzodiazepine receptor, is dramatically up-regulated under pathologic conditions. Activated micro-glia are the main cell type expressing the TSPO at sites of central nervous system pathology. Radioligands for the TSPO can therefore measure active disease in the brain. This article details the synthesis, radio-fluorination, and pharmacologic evaluation of a new TSPO-specific pyrazolopyrimidine, DPA-714. Methods: The affinity of DPA-714 for the TSPO was measured in rat kidney membranes with {sup 3}H-PK11195. The in vitro functional activity of DPA-714 was measured in a steroidogenic assay in which the ability of DPA-714 to increase pregnenolone synthesis was measured with rat C6 glioma cells. The radio-fluorination of DPA-714 was achieved by nucleophilic {sup 18}F-fluoride displacement of the tosylate precursor. {sup 18}F-DPA-714 was assessed in rats harboring unilateral quinolinic acid (QA) lesions. In addition, pretreatment experiments were performed with PK11195 (5 mg/kg), DPA-714 (1 mg/kg), and DPA-713 (1 mg/kg). The in vivo binding and biodistribution of {sup 18}F-DPA-714 were determined in a baboon with PET. Experiments involving presaturation with PK11195 (1.5 mg/kg) and displacement with DPA-714 (1 mg/kg) were conducted to evaluate the specificity of radioligand binding. Results: In vitro binding studies revealed that DPA-714 displayed a high affinity for the TSPO (dissociation constant, 7.0 nM). DPA-714 stimulated pregnenolone synthesis at levels 80% above the baseline. {sup 18}F-DPA-714 was prepared at a 16% radiochemical yield and a specific activity of 270 GBq/{mu}mol. In rats harboring unilateral QA lesions, an 8-fold-higher level of uptake of {sup 18}F-DPA-714 was observed in the ipsilateral striatum than in the contralateral striatum. Uptake in the ipsilateral striatum was shown to be selective because it was inhibited to the level in the contralateral striatum in the presence

  16. History Leaves Salts Behind

    Science.gov (United States)

    2004-01-01

    These plots, or spectra, show that a rock dubbed 'McKittrick' near the Mars Exploration Rover Opportunity's landing site at Meridiani Planum, Mars, has higher concentrations of sulfur and bromine than a nearby patch of soil nicknamed 'Tarmac.' These data were taken by Opportunity's alpha particle X-ray spectrometer, which uses curium-244 to assess the elemental composition of rocks and soil. Only portions of the targets' full spectra are shown to highlight the significant differences in elemental concentrations between 'McKittrick' and 'Tarmac.' Intensities are plotted on a logarithmic scale.A nearby rock named Guadalupe similarly has extremely high concentrations of sulfur, but very little bromine. This 'element fractionation' typically occurs when a watery brine slowly evaporates and various salt compounds are precipitated in sequence.

  17. ChemCam observations of Fluorine in Murray and Stimson units, Gale crater, Mars

    Science.gov (United States)

    Dehouck, E.; Forni, O.; Meslin, P. Y.; Mangold, N.; l'Haridon, J.; Nachon, M.; Cousin, A.; Newsom, H. E.; Clegg, S. M.; Gasnault, O.; Maurice, S.; Wiens, R. C.; Sautter, V.; Lasue, J.

    2016-12-01

    More than 250 fluorine detections have been identified in the Murray and Stimson units (Starting at Sol 760). Up to the Garden City outcrop which is heavily cross-cut by diagenetic veins (Sol 940), fluorine was very frequent. At Garden City, fluorine contents are very high (up to 12 wt.% for the highest point on the Alvord Mountain target). After Garden City and up to the departure from Marias Pass there are very few detections. The rate of detection notably increases after Marias Pass. Different geological environments show F-bearing mineralogy. Before Garden City, F-bearing silicates (phyllosilicates, micas) were found in the lower Pahrump section (e.g., sol 760). Apatites were found in the upper Pahrump sandstones but in close relationship with calcium sulfates and are probably formed in a later stage. Apatites were also found at the contact between the Murray (lacustrine) and Stimson (overlying eolian) formations and they are mostly located in the thin layer above the contact at Marias Pass in the lower-most Stimson. These observations suggest some kind of hydrothermal fluid circulation. Fluorite is mainly found at the Garden City vein complex in dark-tone veins. The presence of this large amount of fluorite suggests acidic leaching or fluid circulation could have leached phosphates, minerals that are easily dissolved by acidic alteration. Mobility of fluorine in fluids due to dissolution of phosphates at low temperature may explain the observed veins, but it does not explain the unique observation of these fluorite veins at Garden City and not in the Pahrump Hills section below. The formations of these dark-toned veins seem to precede the formation of the Ca-sulfate veins. Finally, fluorine and Ca-bearing phases were observed together mainly after Marias Pass (sol >1000) in association with veins that also contain halite. This ubiquitous presence of fluorine bearing fluids may have a profound influence on the preservation of eventual pre-existing form of life.

  18. Synthesis and characterization of fluorinated azadipyrromethene complexes as acceptors for organic photovoltaics

    Directory of Open Access Journals (Sweden)

    Forrest S. Etheridge

    2016-08-01

    Full Text Available Homoleptic zinc(II complexes of di(phenylacetyleneazadipyrromethene (e.g., Zn(WS32 are potential non-fullerene electron acceptors for organic photovoltaics. To tune their properties, fluorination of Zn(WS32 at various positions was investigated. Three fluorinated azadipyrromethene-based ligands were synthesized with fluorine at the para-position of the proximal and distal phenyl groups, and at the pyrrolic phenylacetylene moieties. Additionally, a CF3 moiety was added to the pyrrolic phenyl positions to study the effects of a stronger electron withdrawing unit at that position. The four ligands were chelated with zinc(II and BF2+ and the optical and electrochemical properties were studied. Fluorination had little effect on the optical properties of both the zinc(II and BF2+ complexes, with λmax in solution around 755 nm and 785 nm, and high molar absorptivities of 100 × 103 M−1cm−1 and 50 × 103 M−1cm−1, respectively. Fluorination of Zn(WS32 raised the oxidation potentials by 0.04 V to 0.10 V, and the reduction potentials by 0.01 V to 0.10 V, depending on the position and type of substitution. The largest change was observed for fluorine substitution at the proximal phenyl groups and CF3 substitution at the pyrrolic phenylacetylene moieties. The later complexes are expected to be stronger electron acceptors than Zn(WS32, and may enable charge transfer from other conjugated polymer donors that have lower energy levels than poly(3-hexylthiophene (P3HT.

  19. Direct fluorination of graphene: A theoretical and computational study of its formation and of the resulting magnetic and electronic properties

    Science.gov (United States)

    Aditya, Piali Mitil

    The adsorption of fluorine changes the electronic, mechanical, and magnetic properties of graphene. While graphene is an excellent conductor and a semimetal, fully fluorinated graphene is an insulating wide bandgap semiconductor. The electronic properties of graphene can be modified by controlling the adsorbate concentration to produce conducting, semiconducting or insulating components for nanoscale electronic devices. The high electronegativity of fluorine makes it very reactive to the graphene sheet resulting in structures that are stable under ambient conditions. Moreover, recent reports of spin 1/2 paramagnetism in graphene has invigorated research efforts in this field due the possibility of spin transport devices. While there is a lot of speculation about the origin of the spin, no clear theoretical explanation exists in the literature. Semi local DFT functionals predict that the fluorine adatom is non-magnetic, whereas calculations with hybrid functionals indicate a local moment of 1muB. However, neither approaches can explain the trends in the experimentally observed spin concentration as a function of fluorination percentage. After an introduction in Chapter 1 and an overview of our methods in Chapter 2, in Chapter 3, using density functional theory (DFT) we show that in highly fluorinated graphene, small regions of unfluorinated carbon atoms produce localized magnetic states at the fermi-level. We study the shape and size dependence of these regions on the net spin and find that most odd clusters have a net spin of 1/2 while most even clusters have zero spin. We construct a minimal tight binding model that captures the low energy response of DFT and describes the localized magnetic states produced by the unfluorinated carbon atoms. This model is then solved exactly to include the effect of excited states in the magnetic response and go beyond the mean field predictions of DFT. The model for magnetic carbon regions, when combined with large scale

  20. Salt intake belief, knowledge, and behavior: a cross-sectional study of older rural Chinese adults

    OpenAIRE

    Zhang, Jing; Wu, Tao; Chu, Hongling; Feng, Xiangxian; Shi, Jingpu; Zhang, Ruijuan; Zhang, Yuhong; Zhang, Jianxin; Li, Nicole; Yan, Lijing; Niu, Wenyi; Wu, Yangfeng

    2016-01-01

    Abstract Excess sodium consumption is a major cause of high blood pressure and subsequent vascular disease. However, the factors driving people's salt intake behavior remains largely unknown. This study aims to assess the relationship of salt intake behaviors with knowledge and belief on salt and health among older adults in rural China. A cross-sectional survey was conducted among 4693 older participants (men ?50 and women ?60 years old) randomly selected from 120 rural villages in 5 norther...