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Sample records for thenoyltrifluoroacetone

  1. Photoactive europium(III) centered mesoporous hybrids with 2-thenoyltrifluoroacetone functionalized SBA-16 and organic polymers.

    Science.gov (United States)

    Li, Yajuan; Yan, Bing

    2010-03-14

    A series of novel ternary organic-inorganic mesoporous polymeric hybrids TTFA-S16-Eu-PMMA, TTFA-S16-Eu-PMAA, and TTFA-S16-Eu-PVP (TTFA = 2-Thenoyltrifluoroacetone; PMMA = polymethyl methacrylate; PMAA = polymethacrylic acid; PVP = polyvinylpyrrolidone) have been assembled by the Eu(3+) complex covalently attaching to the TTFA directly functionalized ordered mesoporous SBA-16 and organic polymer. FTIR, UV, XRD, TEM, N(2) adsorption measurements, photoluminescent spectra, and TG plots were characterized, and the results reveal that they all have high surface area, uniformity in the mesostructure, and good crystallinity. In addition, the ternary rare earth mesoporous polymeric hybrids show an overall increase in luminescent lifetime and quantum efficiency compared to binary rare earth mesoporous hybrid TTFA-S16-Eu, especially the mesoporous hybrid with PVP exhibits the highest luminescence quantum efficiency and longest lifetime.

  2. Influence of the ammonium salt anion on the synergistic solvent extraction of lanthanides with mixtures of thenoyltrifluoroacetone and tridecylamine

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    Dukov, I.L.; Jordanov, V.M. [Univ. of Chemical Technology and Metallurgy, Sofia (Bulgaria). Dept. of Inorganic Chemistry

    1998-08-01

    The synergistic solvent extraction of Pr, Gd and Yb with mixtures of thenoyltrifluoroacetone (HTTA) and primary ammonium salt (tridecylammonium chloride or perchlorate, TDAH(Cl, ClO{sub 4})) in C{sub 6}H{sub 6} has been studied. The composition of the extracted species have been determined as Ln(TTA){sub 3}TDAHA(A{sup {minus}} = Cl{sup {minus}} or ClO{sub 4}{sup {minus}}). The values of the equilibrium constant K{sub T,S} have been calculated. The influence of the ammonium salt anion on the extraction process has been discussed. The separation factors of the pairs Gd/Pr and Yb/Gd have been determined.

  3. Fluorometric determination of proteins using the terbium (III)-2-thenoyltrifluoroacetone-sodium dodecyl benzene sulfonate-protein system

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    Jia Zhen [Key Laboratory of Colloid and Interface Chemistry of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Department of Chemistry, Dezhou University, Dezhou 253023 (China); Yang Jinghe [Key Laboratory of Colloid and Interface Chemistry of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China)]. E-mail: yjh@sdu.edu.cn; Wu Xia [Key Laboratory of Colloid and Interface Chemistry of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Wang Fei [Key Laboratory of Colloid and Interface Chemistry of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Guo Changying [Key Laboratory of Colloid and Interface Chemistry of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Liu Shufang [Key Laboratory of Colloid and Interface Chemistry of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China)

    2006-12-15

    It is found that in hexamethylene tetramine (HMTA)-HCl buffer of pH=8.00, proteins can enhance the fluorescence of terbium (III) (Tb{sup 3+})-2-thenoyltrifluoroacetone (TTA)-sodium dodecyl benzene sulfonate (SDBS) system. Based on this, a sensitive method for the determination of proteins is proposed. The experiments indicate that under the optimum conditions, the enhanced fluorescence intensity is in proportion to the concentration of proteins in the range of 4.0x10{sup -9}-7.5x10{sup -6}g/mL for bovine serum albumin (BSA), 5.0x10{sup -9}-1.5x10{sup -5}g/mL for human serum albumin (HSA), 1.0x10{sup -8}-7.5x10{sup -6}g/mL for egg albumin (EA). Their detection limits (S/N=3) are 0.5, 0.8 and 2.0ng/mL, respectively. The interaction mechanism is also studied.

  4. 1H-NMR studies on the ternary complexes of rare-earth ions with thenoyltrifluoroacetone and polyethers in dichloromethane.

    Science.gov (United States)

    Gagabe, Gene Frederick; Satoh, Keiichi; Sawada, Kiyoshi

    2009-07-28

    The structures of the ternary complexes of lanthanoid and yttrium (Ln3+)-thenoyltrifluoroacetonates (tta-) with polyether (POE) in organic phase were investigated by 1H-NMR spectroscopy, where the POEs are crown ethers (18-crown-6 and benzo-18-crown-6) and monodispersed linear polyethers (DEOn: HO-(CH2CH2O-)nC12H25, where n=4, 6, 8). The changes in chemical shift of methylene protons of POE by addition of the adduct complex [Ln(tta)3(POE)] were measured at various Ln3+-to-POE concentration ratios. Chemical shift changes for each proton of POE by the formation of [Ln(tta)3(POE)] were determined. Results revealed that oxygen atoms at the hydroxyl terminal of linear POE have higher tendency to coordinate to the metal ion in [Ln(tta)3] complex. Three (for La3+) or two (for Lu3+ or Y3+) oxygen atoms of the POE coordinate to the metal ion without substitution of tta- ligands to satisfy the metal ion's coordination number of nine or eight, respectively. In the case of 18-membered crown ether complexes, La3+ is incorporated inside the cavity of the POE, displacing one of the three tta- from the inner coordination sphere while the other two remain coordinated to the metal ion. On the other hand, for the adduct of Y3+ complex with crown ether, all three tta- ligands are directly coordinating to the metal ion.

  5. Fluorescence enhancement effect of Eu(III)-thenoyltrifluoroacetone-cetyltrimethyl ammonium bromide in water-dissolved organic matter extracted from wheat straw.

    Science.gov (United States)

    Huang, Fei; Meng, Fanhui; Fan, Mengdi; Zhao, Yanyan; Wu, Xia; Shen, Lin

    2015-01-01

    The fluorescence spectral characteristics of water-dissolved organic matter extracted from wheat straw (DOM-WS) were studied using three-dimensional excitation-emission matrix (3D-EEM) fluorescence spectroscopy. The results indicated that 3D-EEM spectra of DOM-WS showed four different fluorophores: humic-like, visible fulvic-like, UV fulvic-like and protein-like substances. It is interesting that DOM-WS can obviously enhance the fluorescence intensity of Eu(III)-thenoyltrifluoroacetone-cetyltrimethyl ammonium bromide system. On the basis of this study, a new fluorescence method for the determination of trace amounts of Eu(III) was developed. Under the optimal conditions, the enhanced fluorescence intensity was in proportion to the concentration of Eu(III) in the range of 8.0×10(-8)-8.0×10(-7)mol/L. The detection limit (S/N=3) was 1.1×10(-9)mol/L. This method was applied to the analysis of Eu(III) concentration in standard sample and obtained satisfactory results. It may be a new way to use wheat straw effectively. Copyright © 2015 Elsevier B.V. All rights reserved.

  6. Hybrid materials of lanthanide centers/functionalized 2-thenoyltrifluoroacetone/silicon-oxygen network/polymeric chain: coordination bonded assembly, physical characterization, and photoluminescence.

    Science.gov (United States)

    Qiao, Xiao-Fei; Yan, Bing

    2009-06-01

    2-Thenoyltrifluoroacetone (TTA) was grafted onto the coupling agent 3-(triethoxysilyl)-propyl isocyanate (TEPIC) through a hydrogen transfer addition reaction to construct the multifunctional bridge precursor. Other kinds of polymeric precursors (PVPD, PMAA, and PVPDMAA) were synthesized through the addition polymerization reactions using the monomer 4-vinylpyridine and methacrylic acid as the raw materials. The lanthanide compound was then assembled by the coordination effect between precursors and europium ions with the carbonyl, carboxyl groups, or nitrogen atoms. At last, we have utilized the first precursor hydrolyzed with the tetraethoxysilane (TEOS) via the sol-gel copolycondensation process to obtain three kinds of final hybrid polymers. The photoluminescence and microstructural, thermal, and mechanical properties were characterized and the results reveal that the hybrid materials imbedded into the single polymer (PVPD and PMAA) show more efficient intramolecular energy transfer between the europium ion and the modified ligand TTA-Si, bringing the excellent characteristic emission of europium ion. The different configuration of the polymeric precursor introduces a vital different appearance in the microstructure, and the hybrid material with PVPD shows the highest luminescence quantum efficiency and longest lifetime.

  7. Study of the hydrolysis of protactinium (V), at tracer scale, by solvent extraction method with thenoyl-tri-fluoro-acetone (TTA) as chelating agent. Characterization of the partition of TTA in the system TTA / H{sub 2}O / toluene / Na{sup +} / H{sup +} / ClO{sub 4}{sup -}; Contribution a l'etude thermodynamique de l'hydrolyse de Pa(V) a l'echelle des traces par la technique d'extraction liquide-liquide avec la thenoyltrifluoroacetone (TTA). Caracterisation du partage de la thenoyltrifluoroacetone dans le systeme TTA / H{sub 2}O / toluene / Na{sup +} / H{sup +} / ClO{sub 4}{sup -}

    Energy Technology Data Exchange (ETDEWEB)

    Jaussaud, Ch

    2003-01-01

    Hydrolysis of protactinium (V) according to the reactions: PaO(OH){sup 2+} +H{sub 2}O {r_reversible} PaO(OH){sub 2}{sup +} + H{sup +} (K{sub 2}] PaO(OH){sup 2+} +2H{sub 2}O {r_reversible} PaO(OH){sub 5} + H{sup +} (K{sub 3}) has been studied, at tracer scale, by solvent extraction method, with thenoyl-tri-fluoro-acetone (TTA) as chelating agent. A previous study concerning the partition of TTA between two immiscible phases (corresponding to TTA/toluene/Na{sup +}/H{sup +}/ClO{sub 4}{sup -} system) has allowed a complete characterization of this system (partition constants, standard thermodynamic values, TTA hydration degree in toluene). Owing to specific properties of protactinium (V) (sorption onto various materials, formation of colloids), an extremely rigorous protocol has been established, protocol which could be used for other hydrolysable elements. Hydrolysis constants were deduced from a systematic study of partition of Pa(V) as a function TTA and proton concentration, ionic strength and temperature. Extrapolations to zero ionic strength were performed using SIT model and the specific interaction coefficients {epsilon}{sub (i,j)} as well as the Pitzer parameters {beta}{sup (0)} and {beta}{sup (1)} were determined. Standard thermodynamic data relative to hydrolysis equilibriums of Pa(V) were also estimated. (author)

  8. Influence of the amine salt anion on the synergic solvent extraction of praseodymium with mixtures of chelating extractants and tridodecylamine

    Energy Technology Data Exchange (ETDEWEB)

    Dukov, I.L.; Jordanov, V.M. [Higher Inst. of Chemical Technology, Sofia (Bulgaria)

    1995-11-01

    The solvent extraction of Pr with thenoyltrifluoroacetone, (HTTA) or 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one(HP) and tridodecylammonium salt (TDAHA,A{sup -} = Cl{sup -},NO{sub 3}{sup -}, ClO{sub 4}{sup -}) in C{sub 6}H{sub 6} has been studied. The composition of the extracted species has been determined as Pr(TTA){sub 3} TDAHA and TDAH{sup +}[PrP{sub 4}]{sup -}. The values of the equilibrium constants, have been calculated. The extraction mechanism has been discussed on the basis of the experimental data. 34 refs., 6 figs., 2 tabs.

  9. Fluorescent Europium Chelate Stain

    Science.gov (United States)

    Scaff, W. L.; Dyer, D. L.; Mori, K.

    1969-01-01

    The europium chelate of 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (thenoyl-trifluoroacetone; TTA) is firmly bound to microorganisms. It fluoresces brightly at 613 nm with activation at 340 nm. Cells may be stained with 10−3m chelate in 50% ethyl alcohol, followed by washing with 50% ethyl alcohol. Equal or better stains are produced with 10−3m aqueous europium salt, water wash, and 10−2m aqueous TTA. A noncomplexing buffer should be used to maintain the pH at 6.5 to 6.8. Images PMID:4181107

  10. Organophosphate Nerve Agent Detection with Europium Complexes

    Directory of Open Access Journals (Sweden)

    Jake R. Schwierking

    2004-01-01

    Full Text Available We explore the detection of paraoxon, a model compound for nonvolatile organophosphate nerve agents such as VX. The detection utilizes europium complexes with 1,10 phenanthroline and thenoyltrifluoroacetone as sensitizing ligands. Both europium luminescence quenching and luminescence enhancement modalities are involved in the detection, which is simple, rapid, and sensitive. It is adaptable as well to the more volatile fluorophosphate nerve agents. It involves nothing more than visual luminescence observation under sample illumination by an ordinary hand-held ultraviolet lamp.

  11. Photoluminescent Detection of Dissolved Underwater Trace Explosives

    Directory of Open Access Journals (Sweden)

    Tye Langston

    2010-01-01

    Full Text Available A portable, rapid, and economical method for in situ trace explosive detection in aqueous solutions was demonstrated using photoluminescence. Using europium/thenoyltrifluoroacetone as the reagent, dissolved nitroglycerin was fluorescently tagged and detected in seawater solutions without sample preparation, drying, or preconcentration. The chemical method was developed in a laboratory setting and demonstrated in a flow-through configuration using lightweight, inexpensive, commercial components by directly injecting the reagents into a continually flowing seawater stream using a small amount of organic solvent (approximately 8% of the total solution. Europium's vulnerability to vibrational fluorescence quenching by water provided the mode of detection. Without nitroglycerin in the seawater solution, the reagent's fluorescence was quenched, but when dissolved nitroglycerin was present, it displaced the water molecules from the europium/thenoyltrifluoroacetone compound and restored fluorescence. This effort focused on developing a seawater sensor, but performance comparisons were made to freshwater. The method was found to perform better in freshwater and it was shown that certain seawater constituents (such as calcium have an adverse impact. However, the concentrations of these constituents are not expected to vary significantly from the natural seawater used herein.

  12. Layer-by-layer assembly of luminescent ultrathin films by Mg-Al-Eu LDHs nanosheets and organic ligand with high transparency

    Science.gov (United States)

    Zhang, Wenjun; Li, Yanlin; Fan, Hongxian

    2016-01-01

    We fabricated a kind of luminescent ordered multilayer transparent ultrathin films (OMTFs) based on inorganic rare earth doped layered double hydroxides (Mg-Al-Eu LDHs) nanosheets and the organic ligand 2-thenoyltrifluoroacetone (TTA) via layer-by-layer assembly method. At the same time, Polyvinyl Alcohol (PVA) aqueous solution was used as intermediate linkers. UV-visible absorption spectroscopy, X-ray diffraction, fluorescence spectroscopy and scanning electron microscopy were introduced to investigate the structure and properties of these films. Surprisingly, the uniformity and the fluorescence emission intensity of OMTFs which utilized polyvinyl Alcohol (PVA) as intermediate linkers are significantly enhanced compared with that of OMTFs without PVA. Herein, it was found that the fluorescence emission intensity of this kind of ultrathin film with PVA displays a monotonic increase as the number of deposition cycles increasing, and further the films which are highly transparent, uniform and ultrathin have potential applications in the optical display devices.

  13. Excitation energy transfer in europium chelate with doxycycline in the presence of a second ligand in micellar solutions of nonionic surfactants

    Science.gov (United States)

    Smirnova, T. D.; Shtykov, S. N.; Kochubei, V. I.; Khryachkova, E. S.

    2011-01-01

    The complexation of Eu3+ with doxycycline (DC) antibiotic in the presence of several second ligands and surfactant micelles of different types is studied by the spectrophotometric and luminescence methods. It is found that the efficiency of excitation energy transfer in Eu3+-DC chelate depends on the nature of the second ligand and surfactant micelles. Using thenoyltrifluoroacetone (TTA) as an example, it is shown that the second ligand additionally sensitizes the europium fluorescence, and the possibility of intermediate sensitization of DC and then of europium is shown by the example of 1,10-phenanthroline. In all cases, the excitation energy transfer efficiency was increased due to the so-called antenna effect. The decay kinetics of the sensitized fluorescence of the binary and mixed-ligand chelates in aqueous and micellar solutions of nonionic surfactants is studied and the relative quantum yields and lifetimes of fluorescence are determined.

  14. Complex formation of Np(V) with fulvic acid at tracer metal concentration

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    Mueller, K. [Kyoto Univ. (Japan). Dept. of Nuclear Engineering; Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Inst. of Resource Ecology; Sasaki, T. [Kyoto Univ. (Japan). Dept. of Nuclear Engineering

    2013-03-01

    Apparent formation constants of pentavalent Np with fulvic acid (FA) were determined in 0.1 M NaClO{sub 4}, at 25 C using a solvent extraction technique with thenoyltrifluoroacetone (TTA) and phenanthroline (phen) in an isoamyl alcohol solution. The metal concentration was set constant to a tracer level of 10{sup -15} M Np(V), relevant for the far field safety assessment of a nuclear waste disposal site. The impact of several solution conditions, namely pH, ionic strength, the initial fulvic acid concentration and the presence of Ca{sup 2+}, on the complex formation were studied. Similar to the sodium system, the divalent calcium ion effectively prevents complexation of the neptunyl ion with fulvic acid. Furthermore, the derived apparent formation constants were comparatively discussed with literature values obtained at very similar solution conditions. (orig.)

  15. Preparation and characterization of electroluminescent devices based on complexes of {beta}-diketonates of Tb{sup 3+}, Eu{sup 3+}, Gd{sup 3+} ions with macrocyclic ligands and UO{sub 2}{sup 2+} films; Preparacao e caracterizacao de dispositivos eletroluminescentes de complexos de {beta}-dicetonados de ions Tb{sup 3+}, Eu{sup 3+}, Gd{sup 3+} com ligantes macrociclicos e filmes de UO{sub 2}{sup 2+}

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    Gibelli, Edison Bessa

    2010-07-01

    Complexes containing Rare Earth ions are of great interest in the manufacture of electro luminescent devices as organic light emitting devices (OLED). These devices, using rare earth trivalent ions (TR{sup 3+}) as emitting centers, show high luminescence with extremely fine spectral bands due to the structure of their energy levels, long life time and high quantum efficiency. This work reports the preparation of Rare Earth {beta}-diketonate complexes (Tb{sup 3+}, Eu{sup 3+} and Gd{sup 3+}) and (tta - thenoyltrifluoroacetonate and acac - acetylacetonate) containing a ligand macrocyclic crown ether (DB18C6 - dibenzo18coroa6) and polymer films of UO{sub 2}{sup 2+}. The materials were characterized by complexometric titration with EDTA, CH elemental analysis, near infrared absorption spectroscopy, thermal analysis, X-ray diffraction (powder method) and luminescence spectroscopy. For manufacturing the OLED it was used the technique of deposition of thin films by physical vapor (PVD, Physical Vapor Deposition). (author)

  16. A facile access to new diazepines derivatives: Spectral characterization and crystal structures of 7-(thiophene-2-yl)-5-(trifluoromethyl)-2,3-dihydro-1H-1,4-diazepine and 2-thiophene-4-trifluoromethyl-1,5-benzodiazepine

    Science.gov (United States)

    Ahumada, Guillermo; Carrillo, David; Manzur, Carolina; Fuentealba, Mauricio; Roisnel, Thierry; Hamon, Jean-René

    2016-12-01

    The one-pot double condensation reaction of 2-thenoyltrifluoroacetone (2-TTA) with ethylendiamine or o-phenylenediamine, in a 2:1 stoichiometric molar ratio, leads to the formation of 7-(thiophene-2-yl)-5-(trifluoromethyl)-2,3-dihydro-1H-1,4-diazepine 2 and 2-thiophene-4-trifluoromethyl-1,5-benzodiazepine 3, that were isolated in 56 and 53% yields, respectively. The bis(trifluoroacetamide)ethylene derivative 1 was also isolated in 32% yield as a side-product in the reaction of 2-TTA and ethylenediamine. Compounds 1-3 were fully characterized by elemental analysis, FT-IR and multinuclear (1H, 13C and 19F) NMR spectroscopy. In addition, their molecular identities and geometries have been authenticated by single-crystal X-ray diffraction analysis. The spectroscopic and structural data confirm that the 1,4-diazepine 2 and the 1,5-benzodiazepine 3 exist in the imine-enamine and diimine tautomeric forms, respectively, both in solution and in the solid-state.

  17. Photoluminescent study of Polycarbonate (PC) and Poly(9-vinylcarbazole) (PVK) doped films with europium complex; Estudo fotoluminescente de filmes de Policarbonato (PC) e Poli(9-vinilcarbazol) (PVK) dopados com complexo de europio

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    Forster, Pedro Lima

    2010-07-01

    Polymers doped with rare earth complexes are advantaged in film production for many applications in the luminescent field. In this study luminescent polymer obtained from polycarbonate (PC) and poly(9-vinylcarbazole) films doped with diaquatris(thenoyltrifluoroacetonate)europium(III) complex [Eu(tta){sub 3}(H{sub 2}0){sub 2}] were prepared and their calorimetric and luminescent properties in the solid state are reported. The thermal behavior was investigated by differential scanning calorimetry (OSC) and thermogravimetry analysis (TGA). Due of the addition of rare earth Eu(tta){sub 3}(H{sub 2}0){sub 2}] into PC and PVK matrices, changes were observed in the thermal behavior concerning the glass transition and thermal stability. Characteristic broadened narrow bands arising from the {sup 5}D{sub 0} -{yields} {sup 7}F{sub J} transitions (J = 0-4) of Eu{sup 3+} ion indicate the incorporation of the Eu{sup 3+} ions into those polymers. The luminescent films show enhancement emission intensity with an increase in the rare earth concentration in polymeric matrix accompanied by decrease in thermal stability. (author)

  18. Improved color purity and electroluminescent efficiency obtained by modulating thicknesses and evaporation rates of hole block and electron transport layers

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    Zhou Liang; Deng Ruiping; Feng Jing; Li Xiaona; Li Xiyan [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Graduate School of Chinese Academy of Sciences, Beijing 100049 (China); Zhang Hongjie, E-mail: hongjie@ciac.jl.cn [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Graduate School of Chinese Academy of Sciences, Beijing 100049 (China)

    2011-01-15

    In this work, a series of electroluminescent (EL) devices based on trivalent europium (Eu{sup 3+}) complex Eu(TTA){sub 3}phen (TTA thenoyltrifluoroacetone, phen = 1,10-phenanthroline) were fabricated by selecting 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and tris(8-hydroxyquinoline) aluminum (Alq{sub 3}) as hole block and electron transport materials, respectively. Interestingly, we found the transport of electrons decreases gradually with increasing thicknesses and evaporation rates of BCP and Alq{sub 3} layers. Analyzing carrier distribution and EL spectra, we conclude that appropriately modulating the thicknesses and evaporation rates is an efficient way to decrease the accumulation of electrons in HBL, thus suppressing the EL of hole block material. On the other hand, decreasing the transport of electrons can also facilitate the balance of holes and electrons on Eu(TTA){sub 3}phen molecules, thus further enhancing the EL efficiency. As a result, pure Eu{sup 3+} emission with the efficiency as high as 8.49 cd/A was realized by controlling the thicknesses and evaporation rates of BCP and Alq{sub 3} layers to be 30 nm and 0.10 nm/s, 40 nm and 0.10 nm/s, respectively.

  19. Unusual trinuclear complex of copper(II) containing a 4‧-(3-methyl-2-thienyl)-4,2‧:6‧,4″-terpyridine ligand. Structural, spectroscopic, electrochemical and magnetic properties

    Science.gov (United States)

    Toledo, Dominique; Ahumada, Guillermo; Manzur, Carolina; Roisnel, Thierry; Peña, Octavio; Hamon, Jean-René; Pivan, Jean-Yves; Moreno, Yanko

    2017-10-01

    We report the synthesis, characterization, crystal and molecular structure as well as the spectroscopic, electrochemical and magnetic properties of an unexpected trinuclear copper(II) complex (1), made of three Cu(2-TTA)2 units (2-TTA = 2-thenoyltrifluoroacetone) bridged by two 4'-(3-methyl-2-thienyl)-4,2‧:6‧,4″-terpyridine (4-stpy) ligands. The central Cu(II) atom shows an octahedral geometry, while the lateral metal centers present a slightly distorted square pyramidal coordination sphere. It is suggested that the introduction of the relatively bulky substituent groups (2-thienyl and sbnd CF3) in the 2-TTA ligand are responsible of this uncommon coordination mode. The magnetic behavior of 1 is reported in terms of a combination of monomer and dimer units, leading to weak antiferromagnetic interaction (J = -1.93 cm-1). The cyclovoltammogram of 1 exhibits, in the cathodic potential region, three redox events due to Cu2+/Cu+ and Cu+/Cu0 redox couples and to the mono-electronic reduction of the 4-stpy ligand.

  20. Behaviour of Protactinium(V) in complexing media

    Energy Technology Data Exchange (ETDEWEB)

    Di Giandomenico, M.V.; Mendes, M.; Le Naour, C. [CNRS-Univ. Paris-Sud, Institut de Physique Nucleaire, 91406 Orsay cedex (France); DenAuwer, C.; Moisy, Ph. [CEA Marcoule, DEN/DRCP/SCPS, 30207 Bagnols sur Ceze Cedex (France); Hennig, C. [Forschungszentrum Dresden-Rossendorf, 01314 Dresden (Germany)

    2008-07-01

    The physicochemical properties of Protactinium(V) were investigated in acidic complexing media using two levels of element concentration: significant amount with the isotope {sup 231}Pa and tracer scale with the isotope {sup 233}Pa for the structural and thermodynamic study respectively. On one hand, X-ray absorption spectroscopy measurements were performed on Pa(V) samples in hydrofluoric and sulphuric acid of different concentrations and in concentrated hydrochloric acid, allowing to demonstrate the absence of the actinyl moiety in protactinium species, as well as polymerization phenomena. On the other hand, thermodynamic data related to the complexation of Pa(V) with sulphate and chloride ions were determined from solvent extraction experiments involving a chelating agent (thenoyl-tri-fluoro-acetone (TTA)) as extractant. The formation constants of the sulphato complexes of Pa(V) were determined at different ionic strength (0.75 {<=} {mu} {<=} 3 M) and for four values of temperature (10 {<=} {theta} {<=} 60 deg. C). The stability constant of the first chloride complex was estimated at 25 deg. C and {mu} equals 3 M. (authors)

  1. Application of graphene oxide-silica composite reinforced hollow fibers as a novel device for pseudo-stir bar solid phase microextraction of sulfadiazine in different matrices prior to its spectrophotometric determination.

    Science.gov (United States)

    Kazemi, Elahe; Haji Shabani, Ali Mohammad; Dadfarnia, Shayessteh

    2017-04-15

    This study presents a novel, simple and efficient pseudo-stir bar solid phase microextraction method for separation and preconcentration of sulfadiazine. To develop the method, a graphene oxide-silica composite reinforced hollow fiber was prepared via sol-gel technology and used as a novel device to extract sulfadiazine. The retained sulfadiazine was eluted using 180μL of methanol/acetic acid (6:4) and quantified by fiber optic linear array spectrophotometry based on the formation of its azo dye with thenoyltrifluoroacetone. Under optimized conditions, the method exhibited a linear dynamic range of 5-150μgL -1 with a detection limit of 1.5μgL -1 and an enrichment factor of 100. The relative standard deviations of 2.9% and 5.8% (n=6) were obtained at 60μgL -1 level of sulfadiazine for intra- and inter-day analysis respectively. The method was successfully applied to determine sulfadiazine in honey, milk, human urine and environmental water samples. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. On the quenching of trivalent terbium luminescence by ligand low lying triplet state energy and the role of the {sup 7}F{sub 5} level: The [Tb(tta){sub 3} (H{sub 2}O){sub 2}] case

    Energy Technology Data Exchange (ETDEWEB)

    Souza, A.S., E-mail: adelmosaturnino@hotmail.com [Departamento de Química Fundamental, Universidade Federal de Pernambuco, 50670-901 Recife, PE (Brazil); Nunes, L.A. [Instituto de Física de São Carlos, Universidade de São Paulo, 13560-970 São Carlos, SP (Brazil); Felinto, M.C.F.C. [Instituto de Pesquisas Energéticas e Nucleares-IPEN, 05505-800 São Paulo, SP (Brazil); Brito, H.F. [Instituto de Química, Universidade de São Paulo, 05508-900 São Paulo, SP (Brazil); Malta, O.L. [Departamento de Química Fundamental, Universidade Federal de Pernambuco, 50670-901 Recife, PE (Brazil)

    2015-11-15

    In this work we discuss the observed Tb{sup 3+} ion luminescence quenching, due to the relative ligand low lying triplet state energy, in the [Tb(tta){sub 3} (H{sub 2}O){sub 2}] compound at low and room temperature (tta=thenoyltrifluoroacetonate). Theoretical energy transfer rates, for both multipolar and exchange mechanisms, were calculated and discussed on the basis of selection rules and energy mismatch conditions from the [Tb(tta){sub 3} (H{sub 2}O){sub 2}] emission spectra. We have concluded that the exchange mechanism by far dominates, in the present case, and that the long first excited state {sup 7}F{sub 5} lifetime (in the millisecond scale) plays a crucial role in the Tb{sup 3+} luminescence quenching. - Highlights: • The energy exchange between the ligand T{sub 1} and Tb{sup 3+5}D{sub 4} levels occur by the exchange interaction. • The Tb{sup 3+} first excited {sup 7}F{sub 5} level plays a crucial role in this process due to its long lifetime. • At room temperature the energy exchanged between the {sup 5}D{sub 4} level of the Tb{sup 3+} ion and the T{sub 1} of the ligand is lost via the intersystem crossing T{sub 1} → S{sub 0} channel.

  3. Angiotensin II Induces C-Reactive Protein Expression via AT1-ROS-MAPK-NF-κB Signal Pathway in Hepatocytes

    Directory of Open Access Journals (Sweden)

    Jingjing Zhao

    2013-09-01

    Full Text Available Background: C-reactive protein (CRP participates in development of inflammatory diseases. Hepatocytes are a major contributor of circulating CRP. Although angiotensin II (Ang II is known to evoke inflammatory response, it remains unknown whether Ang II induces CRP expression in hepatocytes. The present study observed effect of Ang II on CRP expression and the related signal pathway in hepatocytes. Methods: mRNA and protein expressions in human hepatocytes were determined with RT-PCR and Western blot respectively. Reactive oxygen species (ROS was measured using a fluorescence probe. CRP in liver and serum of rats was determined by immunohistochemistry and ELISA respectively. Results: Ang II induced mRNA and protein expression of CRP in hepatocytes and increased CRP production in liver and CRP level in serum. Losartan reduced Ang II- induced CRP expression in hepatocytes. Losartan and thenoyltrifluoroacetone decreased Ang II-stimulated ROS production. N-acetylcysteine antagonized Ang II-induced CRP expression. Losartan and N-acetylcysteine inhibited Ang II-activated ERK1/2. Unlike ERK1/2, only losartan inhibited Ang II-activated JNK. Furthermore, pyrrolidine dithiocarbamate abolished Ang II-induced CRP expression. Conclusion: Ang II has ability to induce CRP expression in hepatocytes in vitro and in vivo through AT1 receptor followed by ROS, MAPK and NF-κB signal pathway.

  4. Efficient visible and near-infrared photoluminescent attapulgite-based lanthanide one-dimensional nanomaterials assembled by ion-pairing interactions.

    Science.gov (United States)

    Xu, Jun; Zhang, Ye; Chen, Hao; Liu, Weisheng; Tang, Yu

    2014-06-07

    Attapulgite, a one-dimensional fibrillar nanomaterial present in nature, with its extreme stability, is a promising material to act as a new carrier of luminescent lanthanide complexes for further applications. Herein, a series of lanthanide complexes Na[Ln(TTA)4] have been attached to attapulgite (Atta) via ion-pairing interactions, generating the first example of attapulgite-based visible and near-infrared (NIR) luminescent lanthanide one-dimensional nanomaterials, where TTA is 2-thenoyltrifluoroacetonate and Ln is Eu, Sm, Nd, Er or Yb. The hybrid materials were characterized by CHN elemental analysis, inductively coupled plasma-atomic emission spectroscopy (ICP), powder X-ray diffraction (PXRD), thermogravimetry (TG), transmission electron microscopy (TEM), and UV-vis absorption spectra. In order to investigate the photophysical behaviours of these materials, the visible and NIR luminescent spectra and the energy transfer process have been systematically investigated. Moreover, efforts have been made to produce Eu- and Sm-based plastic attapulgite materials by utilizing poly(methyl methacrylate) (PMMA) matrices, and the dispersibility of the lanthanide-doped hybrids in PMMA provides them with a high mechanical strength. The lanthanide-doped attapulgite appears to be an interesting material for photophysical applications. The results of this work would have potential significance for the design and assembly of luminescent lanthanide materials for light-emitting diodes (LED), sunlight-conversion films, optical amplifiers, solar concentrators, and lasers.

  5. Bright electroluminescence from a chelate phosphine oxide Eu{sup III} complex with high thermal performance

    Energy Technology Data Exchange (ETDEWEB)

    Xu Hui [School of Chemistry and Materials, Heilongjiang University, 74 Xuefu Road, Nangang District, Harbin 150080, Heilongjiang Province (China); Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications, 66 Xinmofan Road, Nanjing 21003, Jiangsu Province (China); Yin Kun; Wang Lianhui [Institute of Advanced Materials (IAM), Nanjing University of Posts and Telecommunications, 66 Xinmofan Road, Nanjing 21003, Jiangsu Province (China); Huang Wei [Institute of Advanced Materials (IAM), Fudan University, 220 Handan Road, Shanghai 200433 (China)], E-mail: wei-huang@njupt.edu.cn

    2008-10-01

    The chelate phosphine oxide ligand 1,8-bis(diphenylphosphino)naphthalene oxide (NaPO) was used to prepare complex 1 tris(2-thenoyltrifluoroacetonate)(1,8-bis(diphenylphosphino)naphthalene oxide)europium(III). The rigid structure of NaPO makes 1 have more compact structure resulting in a temperature of glass transition as high as 147 deg. C, which is the highest in luminescent Eu{sup III} complexes, and a higher decomposition temperature of 349 deg. C. The improvement of carrier transfer ability of NaPO was proved by Gaussian simulation. The multi-layered electroluminescent device based on 1 had a low turn-on voltage of 6.0 V, the maximum brightness of 601 cd m{sup -2} at 21.5 V and 481.4 mA cm{sup -2}, and the excellent voltage-independent spectral stability. These properties demonstrated NaPO cannot only be favorable to form the rigid and compact complex structure, and increase the thermal and morphological stability of the complex, but also reduce the formation of the exciplex.

  6. Enhanced emission from Eu(III) beta-diketone complex combined with ether-type oxygen atoms of di-ureasil organic-inorganic hybrids

    CERN Document Server

    Molina, C; Messaddeq, Y; Ribeiro, S J L; Silva, M A P; Zea-Bermudez, V D; Carlos, L D

    2003-01-01

    Organic-inorganic hybrids, named di-ureasils and described by polyether-based chains grafted to both ends to a siliceous backbone through urea cross linkages, were used as hosts for incorporation of the well-known coordination complex of trivalent europium (Eu sup 3 sup +) ions described by the formula [Eu(TTA) sub 3 (H sub 2 O) sub 2] (where TTA stands for thenoyltrifluoroacetone). By comparing with Eu sup 3 sup + -doped di-ureasil without complex form the new materials prepared here enhanced the quantum efficiency for photoemission of Eu sup 3 sup + ions. The enhancement can be explained by the coordination ability of the organic counterpart of the host structure which is strong enough to displace water molecules in [Eu(TTA) sub 3 (H sub 2 O) sub 2] from the rare earth neighbourhood after the incorporation process. High intensity of Eu sup 3 sup + emission was observed with a low non-radiative decay rate under ultraviolet excitation. The quantum efficiency calculated from the decay of sup 5 D sub 0 emission...

  7. Lanthanide-doped luminescent ionogels.

    Science.gov (United States)

    Lunstroot, Kyra; Driesen, Kris; Nockemann, Peter; Van Hecke, Kristof; Van Meervelt, Luc; Görller-Walrand, Christiane; Binnemans, Koen; Bellayer, Séverine; Viau, Lydie; Le Bideau, Jean; Vioux, André

    2009-01-14

    Ionogels are solid oxide host networks confining at a meso-scale ionic liquids, and retaining their liquid nature. Ionogels were obtained by dissolving lanthanide(III) complexes in the ionic liquid 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [C6mim][Tf2N], followed by confinement of the lanthanide-doped ionic liquid mixtures in the pores of a nano-porous silica network. [C6mim][Ln(tta)4], where tta is 2-thenoyltrifluoroacetonate and Ln=Nd, Sm, Eu, Ho, Er, Yb, and [choline]3[Tb(dpa)3], where dpa=pyridine-2,6-dicarboxylate (dipicolinate), were chosen as the lanthanide complexes. The ionogels are luminescent, ion-conductive inorganic-organic hybrid materials. Depending on the lanthanide(III) ion, emission in the visible or the near-infrared regions of the electromagnetic spectrum was observed. The work presented herein highlights that the confinement did not disturb the first coordination sphere of the lanthanide ions and also showed the excellent luminescence performance of the lanthanide tetrakis beta-diketonate complexes. The crystal structures of the complexes [C6mim][Yb(tta)4] and [choline]3[Tb(dpa)3] are reported.

  8. High-resolution Thermal Micro-imaging Using Europium Chelate Luminescent Coatings.

    Science.gov (United States)

    Benseman, Timothy M; Hao, Yang; Vlasko-Vlasov, Vitalii K; Welp, Ulrich; Koshelev, Alexei E; Kwok, Wai-Kwong; Divan, Ralu; Keiser, Courtney; Watanabe, Chiharu; Kadowaki, Kazuo

    2017-04-16

    Micro-electronic devices often undergo significant self-heating when biased to their typical operating conditions. This paper describes a convenient optical micro-imaging technique which can be used to map and quantify such behavior. Europium thenoyltrifluoroacetonate (EuTFC) has a 612 nm luminescence line whose activation efficiency drops strongly with increasing temperature, due to T-dependent interactions between the Eu3+ ion and the organic chelating compound. This material may be readily coated on to a sample surface by thermal sublimation in vacuum. When the coating is excited with ultraviolet light (337 nm) an optical micro-image of the 612 nm luminescent response can be converted directly into a map of the sample surface temperature. This technique offers spatial resolution limited only by the microscope optics (about 1 micron) and time resolution limited by the speed of the camera employed. It offers the additional advantages of only requiring comparatively simple and non-specialized equipment, and giving a quantitative probe of sample temperature.

  9. Hydrophilic actinide complexation studied by solvent extraction radiotracer technique

    Energy Technology Data Exchange (ETDEWEB)

    Rydberg, J. [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Nuclear Chemistry and Radiochemistry Consultant Group, Vaestra Froelunda (Sweden)

    1996-10-01

    Actinide migration in the ground water is enhanced by the formation of water soluble complexes. It is essential to the risk analysis of a wet repository to know the concentration of central atoms and the ligands in the ground water, and the stability of complexes formed between them. Because the chemical behavior at trace concentrations often differ from that at macro concentrations, it is important to know the chemical behavior of actinides at trace concentrations in ground water. One method used for such investigations is the solvent extraction radiotracer (SXRT) technique. This report describes the SXRT technique in some detail. A particular reason for this analysis is the claim that complex formation constants obtained by SXRT are less reliable than results obtained by other techniques. It is true that several difficulties are encountered in the application of SXRT technique to actinide solution, such as redox instability, hydrophilic complexation by side reactions and sorption, but it is also shown that a careful application of the SXRT technique yields results as reliable as by any other technique. The report contains a literature survey on solvent extraction studies of actinide complexes formed in aqueous solutions, particularly by using the organic reagent thenoyltrifluoroacetone (TTA) dissolved in benzene or chloroform. Hydrolysis constants obtained by solvent extraction are listed as well as all actinide complexes studied by SX with inorganic and organic ligands. 116 refs, 11 tabs.

  10. Effect of silver nanoparticles on luminescent properties of europium complex in di-ureasil hybrid materials

    Energy Technology Data Exchange (ETDEWEB)

    Guo Xianmin [Key Laboratory of Rare Earth Chemistry and Physics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Changchun 130022 (China); Fu Lianshe [Key Laboratory of Rare Earth Chemistry and Physics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Changchun 130022 (China)]. E-mail: fu@ciac.jl.cn; Zhang Hongjie [Key Laboratory of Rare Earth Chemistry and Physics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Changchun 130022 (China)]. E-mail: hongjie@ciac.jl.cn; Gao Shuyan [Key Laboratory of Rare Earth Chemistry and Physics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Changchun 130022 (China); Yu Jiangbo [Key Laboratory of Rare Earth Chemistry and Physics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Changchun 130022 (China)

    2007-01-15

    Organic-inorganic hybrids containing luminescent lanthanide complex Eu(tta){sub 3}phen (tta=thenoyltrifluoroaceton, phen=1,10-phenanthroline) and silver nanoparticles have been prepared via mixing rare earth complex and nanoparticles with the precursors of di-ureasil using a sol-gel process. The obtained hybrid materials with transparent and elastomeric features were characterized by transmission electron microscope, solid-state {sup 29}Si magic-angle spinning NMR spectra, diffuse reflectance, UV-visible absorption and photoluminescence spectroscopies. The effect of the silver nanoparticles on the luminescence properties was investigated. The experimental results showed that the luminescence intensity of the Eu(tta){sub 3}phen complex could be enhanced by less than ca. 9.5 nM of silver nanoparticles with the average diameter of 4 nm, and reached its maximum at the concentration of ca. 3.6 nM. Further increasing the concentration of the silver nanoparticles (>9.5 nM) made the luminescence quenched. The enchancement and quench mechnism was discussed.

  11. Hafnium(IV) complexation with oxalate at variable temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Friend, Mitchell T.; Wall, Nathalie A. [Washington State Univ., Pullmanm, WA (United States). Dept. of Chemistry

    2017-08-01

    Appropriate management of fission products in the reprocessing of spent nuclear fuel (SNF) is crucial in developing advanced reprocessing schemes. The addition of aqueous phase complexing agents can prevent the co-extraction of these fission products. A solvent extraction technique was used to study the complexation of Hf(IV) - an analog to fission product Zr(IV) - with oxalate at 15, 25, and 35 C in 1 M HClO{sub 4} utilizing a {sup 175+181}Hf radiotracer. The mechanism of the solvent extraction system of 10{sup -5} M Hf(IV) in 1 M HClO{sub 4} to thenoyltrifluoroacetone (TTA) in toluene demonstrated a 4{sup th}-power dependence in both TTA and H{sup +}, with Hf(TTA){sub 4} the only extractable species. The equilibrium constant for the extraction of Hf(TTA){sub 4} was determined to be log K{sub ex}=7.67±0.07 (25±1 C, 1 M HClO{sub 4}). The addition of oxalate to the aqueous phase decreased the distribution ratio, indicating aqueous Hf(IV)-oxalate complex formation. Polynomial fits to the distribution data identified the formation of Hf(ox){sup 2+} and Hf(ox){sub 2(aq)} and their stability constants were measured at 15, 25, and 35 C in 1 M HClO{sub 4}. van't Hoff analysis was used to calculate Δ{sub r}G, Δ{sub r}H, and Δ{sub r}S for these species. Stability constants were observed to increase at higher temperature, an indication that Hf(IV)-oxalate complexation is endothermic and driven by entropy.

  12. The roles of mitochondria in radiation-induced autophagic cell death in cervical cancer cells.

    Science.gov (United States)

    Chen, Zongyan; Wang, Benli; Yu, Feifei; Chen, Qiao; Tian, Yuxi; Ma, Shumei; Liu, Xiaodong

    2016-03-01

    Mitochondria as the critical powerhouse of eukaryotic cells play important roles in regulating cell survival or cell death. Under numerous stimuli, impaired mitochondria will generate massive reactive oxygen species (ROS) which participate in the regulation of vital signals and could even determine the fate of cancer cells. While the roles of mitochondria in radiation-induced autophagic cell death still need to be elucidated. Human cervical cancer cell line, Hela, was used, and the SOD2 silencing model (SOD2-Ri) was established by gene engineering. Cell viability was detected by methyl thiazolyl tetrazolium (MTT) assays, MitoTracker Green staining was used to detect mitochondrial mass, Western blot was used to detect protein expression, and the level of ROS, autophagy, and mitochondrial membrane potential (MMP) were analyzed by flow cytometry. Ionizing radiation (IR) could induce the increase of MAPLC3-II/MAPLC3-I ratio, Beclin1 expression, and ROS generation but decrease the MMP in a time-dependent manner. After SOD2 silencing, the IR-induced changes of ROS and the MMP were significantly enhanced. Moreover, both the radio sensitivity and autophagy increased in SOD2-Ri cells. Whereas, compared with SOD2-Ri, the opposite results were obtained by NAC, an antioxidant. After the treatment with the inhibitor of mitochondrial electron-transport chain complex II, thenoyltrifluoroacetone (TTFA), the rate of autophagy, ROS, and the total cell death induced by IR increased. In addition, the decrease of MMP was more obvious. However, these results were reversed by cyclosporine A (CsA). IR could induce ROS generation and mitochondrial damage which lead to autophagic cell death in Hela cells.

  13. Enhancement of hydrogen peroxide formation by protophores and ionophores in antimycin-supplemented mitochondria

    Science.gov (United States)

    Cadenas, Enrique; Boveris, Alberto

    1980-01-01

    Rat and pigeon heart mitochondria supplemented with antimycin produce 0.3–1.0nmol of H2O2/min per mg of protein. These rates are stimulated up to 13-fold by addition of protophores (carbonyl cyanide p-trifluoromethoxyphenylhydrazone, carbonyl cyanide m-chloromethoxyphenylhydrazone and pentachlorophenol). Ionophores, such as valinomycin and gramicidin, and Ca2+ also markedly stimulated H2O2 production by rat heart mitochondria. The enhancement of H2O2 generation in antimycin-supplemented mitochondria and the increased O2 uptake of the State 4-to-State 3 transition showed similar protophore, ionophore and Ca2+ concentration dependencies. Thenoyltrifluoroacetone and N-bromosuccinimide, which inhibit succinate–ubiquinone reductase activity, also decreased mitochondrial H2O2 production. Addition of cyanide to antimycin-supplemented beef heart submitochondrial particles inhibited the generation of O2−, the precursor of mitochondrial H2O2. This effect was parallel to the increase in cytochrome c reduction and it is interpreted as indicating the necessity of cytochrome c13+ to oxidize ubiquinol to ubisemiquinone, whose autoxidation yields O2−. The effect of protophores, ionophores and Ca2+ is analysed in relation to the propositions of a cyclic mechanism for the interaction of ubiquinone with succinate dehydrogenase and cytochromes b and c1 [Wikstrom & Berden (1972) Biochim. Biophys. Acta 283, 403–420; Mitchell (1976) J. Theor. Biol. 62, 337–367]. A collapse in membrane potential, increasing the rate of ubisemiquinone formation and O2− production, is proposed as the molecular mechanism for the enhancement of H2O2 formation rates observed on addition of protophores, ionophores and Ca2+. PMID:7406888

  14. Leptin induces mitochondrial superoxide production and monocyte chemoattractant protein-1 expression in aortic endothelial cells by increasing fatty acid oxidation via protein kinase A.

    Science.gov (United States)

    Yamagishi, S I; Edelstein, D; Du, X L; Kaneda, Y; Guzmán, M; Brownlee, M

    2001-07-06

    Leptin, a circulating hormone secreted mainly from adipose tissues, is involved in the control of body weight. The plasma concentrations are correlated with body mass index, and are reported to be high in patients with insulin resistance, which is one of the major risk factors for cardiovascular disease. However, the direct effect of leptin on vascular wall cells is not fully understood. In this study, we investigated the effects of leptin on reactive oxygen species (ROS) generation and expression of monocyte chemoattractant protein-1 (MCP-1) in bovine aortic endothelial cells (BAEC). We found that leptin increases ROS generation in BAEC in a dose-dependent manner and that its effects are additive with those of glucose. Rotenone, thenoyltrifluoroacetone (TTFA), carbonyl cyanide m-chlorophenylhydrazone (CCCP), Mn(III)tetrakis (4-benzoic acid) porphyrin (MnTBAP), uncoupling protein-1 (UCP1) HVJ-liposomes, or manganese superoxide dismutase (MnSOD) HVJ-liposomes completely prevented the effect of leptin, suggesting that ROS arise from mitochondrial electron transport. Leptin increased fatty acid oxidation by stimulating the activity of carnitine palmitoyltransferase-1 (CPT-1) and inhibiting that of acetyl-CoA carboxylase (ACC), pace-setting enzymes for fatty acid oxidation and synthesis, respectively. Leptin-induced ROS generation, CPT-1 activation, ACC inhibition, and MCP-1 overproduction were found to be completely prevented by either genistein, a tyrosine kinase inhibitor, H-89, a protein kinase A (PKA) inhibitor, or tetradecylglycidate, a CPT-1 inhibitor. Leptin activated PKA, and the effects of leptin were inhibited by the cAMP antagonist Rp-cAMPS. These results suggest that leptin induces ROS generation by increasing fatty acid oxidation via PKA activation, which may play an important role in the progression of atherosclerosis in insulin-resistant obese diabetic patients.

  15. An insight into the epitaxial nanostructures of NiO and CeO{sub 2} thin film dielectrics for AlGaN/GaN heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Lo Nigro, Raffaella, E-mail: raffaella.lonigro@imm.cnr.it [Istituto per la Microelettronica e Microsistemi-Consiglio Nazionale delle Ricerche – (IMM-CNR), Strada VIII 5, 95121 Catania (Italy); Fisichella, Gabriele [Istituto per la Microelettronica e Microsistemi-Consiglio Nazionale delle Ricerche – (IMM-CNR), Strada VIII 5, 95121 Catania (Italy); Battiato, Sergio [Dipartimento di Scienze Chimiche, Università degli Studi di Catania, and INSTM udr Catania, viale Andrea Doria 6, 95125 Catania (Italy); Greco, Giuseppe; Fiorenza, Patrick; Roccaforte, Fabrizio [Istituto per la Microelettronica e Microsistemi-Consiglio Nazionale delle Ricerche – (IMM-CNR), Strada VIII 5, 95121 Catania (Italy); Malandrino, Graziella [Dipartimento di Scienze Chimiche, Università degli Studi di Catania, and INSTM udr Catania, viale Andrea Doria 6, 95125 Catania (Italy)

    2015-07-15

    Nickel oxide and cerium oxide thin films have been grown by metal-organic chemical vapor deposition on AlGaN/GaN heterostructures. Thin and epitaxial layers have been already obtained at low temperature (500 °C). Despite the two oxides possess the same crystal structure (face cubic centered compounds), different structural relationships have been observed with respect to the substrate. In particular, nickel oxide films were epitaxially grown along the <111> direction, while cerium oxide thin films showed <111> and <100> preferential orientations. These structural relationships have been justified by geometric and/or kinetics factors. In both cases, the epitaxial growth has been obtained at low temperature by the implementation of two second generation metal precursors, namely the nickel 2-thenoyl-trifluoroacetonate adduct with the tetramethylethylendiamine and cerium 1,1,1,5,5,5-hexafluoroacetlyacetonate adduct with bis(2-methoxyethyl) ether. Electrical characterization demonstrated that these films can be very promising as gate dielectrics for AlGaN/GaN transistors technology. In fact, the two oxide films showed really interesting electric properties such as dielectric constants (ε{sub NiO} = 11.7 and ε{sub CeO2} = 26) close to the bulk values. Finally, it is noteworthy that among the widely used physical deposition methods, in this paper a chemical based deposition technique has been addressed for the epitaxial growth at low temperature of oxide thin films to be implemented in microelectronics applications. - Highlights: • NiO and CeO{sub 2} films were grown as gate dielectric on GaN microelectronics devices. • <111>Epitaxial NiO growth was obtained at low temperature by MOCVD on GaN. • Oriented <111> and <100> CeO{sub 2} films were grown at low temperature by MOCVD on GaN. • Different orientations were explained by geometrical factors and theoretical models. • NiO and CeO{sub 2} electrical properties shown promising gate dielectric behaviours.

  16. Chemical and nuclear properties of Rutherfordium (Element 104)

    Energy Technology Data Exchange (ETDEWEB)

    Kacher, Christian D. [Univ. of California, Berkeley, CA (United States)

    1995-10-30

    The chemical-properties of rutherfordium (Rf) and its group 4 homologs were studied by sorption on glass support surfaces coated with cobalt(II)ferrocyanide and by solvent extraction with tributylphosphate (TBP) and triisooctylamine (TIOA). The surface studies showed that the hydrolysis trend in the group 4 elements and the pseudogroup 4 element, lb, decreases in the order Rf>Zr≈Hf>Th. This trend was attributed to relativistic effects which predicted that Rf would be more prone to having a coordination number of 6 than 8 in most aqueous solutions due to a destabilization of the 6d5/2 shell and a stabilization of the 7pI/2 shell. This hydrolysis trend was confirmed in the TBP/HBr solvent extraction studies which showed that the extraction trend decreased in the order Zr>Hf>Rf?Ti for HBr, showing that Rf and Ti did not extract as well because they hydrolyzed more easily than Zr and Hf. The TIOA/HF solvent extraction studies showed that the extraction trend for the group 4 elements decreased in the order Ti>Zr≈Hf>Rf, in inverse order from the trend of ionic radii Rf>Zr≈Hf>Ti. An attempt was made to produce 263Rf (a) via the 248Cm(22Ne, α3n) reaction employing thenoyltrifluoroacetone (TTA) solvent extraction chemistry and (b) via the 249Bk(18O,4n) reaction employing the Automated Rapid Chemistry Apparatus (ARCA). In the TTA studies, 16 fissions were observed but were all attributed to 256Fm. No alpha events were observed in the Rf chemical fraction. A 0.2 nb upper limit production cross section for the 248Cm(22Ne, α3n)263Rf reaction was calculated assuming the 500-sec half-life reported previously by Czerwinski et al. [CZE92A].

  17. Hypoxic vasoconstriction of partial muscular intra-acinar pulmonary arteries in murine precision cut lung slices

    Directory of Open Access Journals (Sweden)

    Goldenberg Anna

    2006-06-01

    Full Text Available Abstract Background Acute alveolar hypoxia causes pulmonary vasoconstriction (HPV which serves to match lung perfusion to ventilation. The underlying mechanisms are not fully resolved yet. The major vascular segment contributing to HPV, the intra-acinar artery, is mostly located in that part of the lung that cannot be selectively reached by the presently available techniques, e.g. hemodynamic studies of isolated perfused lungs, recordings from dissected proximal arterial segments or analysis of subpleural vessels. The aim of the present study was to establish a model which allows the investigation of HPV and its underlying mechanisms in small intra-acinar arteries. Methods Intra-acinar arteries of the mouse lung were studied in 200 μm thick precision-cut lung slices (PCLS. The organisation of the muscle coat of these vessels was characterized by α-smooth muscle actin immunohistochemistry. Basic features of intra-acinar HPV were characterized, and then the impact of reactive oxygen species (ROS scavengers, inhibitors of the respiratory chain and Krebs cycle metabolites was analysed. Results Intra-acinar arteries are equipped with a discontinuous spiral of α-smooth muscle actin-immunoreactive cells. They exhibit a monophasic HPV (medium gassed with 1% O2 that started to fade after 40 min and was lost after 80 min. This HPV, but not vasoconstriction induced by the thromboxane analogue U46619, was effectively blocked by nitro blue tetrazolium and diphenyleniodonium, indicating the involvement of ROS and flavoproteins. Inhibition of mitochondrial complexes II (3-nitropropionic acid, thenoyltrifluoroacetone and III (antimycin A specifically interfered with HPV, whereas blockade of complex IV (sodium azide unspecifically inhibited both HPV and U46619-induced constriction. Succinate blocked HPV whereas fumarate had minor effects on vasoconstriction. Conclusion This study establishes the first model for investigation of basic characteristics of HPV

  18. Method development for compensating temperature effects in pressure sensitive paint measurements

    Science.gov (United States)

    Demandante, Carlo Greg N.

    1994-01-01

    Pressure sensitive luminescent paints (PSP) have recently emerged as a viable technique for aerodynamic pressure measurements. The technique uses a surface coating which contains probe molecules that luminesce when excited by light of an appropriate wavelength. The photoluminescence of these materials is known to be quenched by the presence of molecular oxygen. Since oxygen is a fixed mole fraction of the air, the coating's luminescence intensity varies inversely with air pressure. Digital imaging of the luminescence varying across a coated surface produces a pressure distribution map over that surface. One difficulty encountered with this technique is the temperature effect on the luminescence intensity. Present PSP formulations have significant sensitivity to temperature. At the moment, the most practical way of correcting for temperature effects is to calibrate the paint in place at the operating temperatures by using a few well-placed pressure taps. This study is looking at development of temperature indicating coatings that can be applied and measured concurrently with PSP, and use the temperature measurement to compute the correct pressure. Two methods for this dual paint formulation are proposed. One method will use a coating that consists of temperature sensitive phosphors in a polymer matrix. This is similar in construction to PSP, except that the probe molecules used are selected primarily for their temperature sensitivity. Both organic phosphors (e.g., europium thenoyltrifluoroacetonate, bioprobes) and inorganic phosphors (e.g., Mg4(F)GeO6:Mn, La2O2S:Eu, Radelin Type phosphors, Sylvania Type phosphors) will be evaluated for their temperature sensing potential. The next method will involve a novel coating composing of five membered heterocyclic conducting polymers which are known to show temperature dependent luminescence (e.g., poly(3-alkylthiopene), poly(3-alkylselenophene), poly(3-alkylfuran)). Both methods will involve applying a bottom layer of

  19. Cytosolic calcium mediates RIP1/RIP3 complex-dependent necroptosis through JNK activation and mitochondrial ROS production in human colon cancer cells.

    Science.gov (United States)

    Sun, Wen; Wu, Xiaxia; Gao, Hongwei; Yu, Jie; Zhao, Wenwen; Lu, Jin-Jian; Wang, Jinhua; Du, Guanhua; Chen, Xiuping

    2017-07-01

    Necroptosis is a form of programmed necrosis mediated by signaling complexes with receptor-interacting protein 1 (RIP1) and RIP3 kinases as the main mediators. However, the underlying execution pathways of this phenomenon have yet to be elucidated in detail. In this study, a RIP1/RIP3 complex was formed in 2-methoxy-6-acetyl-7-methyljuglone (MAM)-treated HCT116 and HT29 colon cancer cells. With this formation, mitochondrial reactive oxygen species (ROS) levels increased, mitochondrial depolarization occurred, and ATP concentrations decreased. This process was identified as necroptosis. This finding was confirmed by experiments showing that MAM-induced cell death was attenuated by the pharmacological or genetic blockage of necroptosis signaling, including RIP1 inhibitor necrostatin-1s (Nec-1s) and siRNA-mediated gene silencing of RIP1 and RIP3, but was unaffected by caspase inhibitor z-vad-fmk or necrosis inhibitor 2-(1H-Indol-3-yl)-3-pentylamino-maleimide (IM54). Transmission electron microscopy (TEM) analysis further revealed the ultrastructural features of MAM-induced necroptosis. MAM-induced RIP1/RIP3 complex triggered necroptosis through cytosolic calcium (Ca2+) accumulation and sustained c-Jun N-terminal kinase (JNK) activation. Both calcium chelator BAPTA-AM and JNK inhibitor SP600125 could attenuate necroptotic features, including mitochondrial ROS elevation, mitochondrial depolarization, and ATP depletion. 2-thenoyltrifluoroacetone (TTFA), which is a mitochondrial complex II inhibitor, was found to effectively reverse both MAM induced mitochondrial ROS generation and cell death, indicating the complex II was the ROS-producing site. The essential role of mitochondrial ROS was confirmed by the protective effect of overexpression of manganese superoxide dismutase (MnSOD). MAM-induced necroptosis was independent of TNFα, p53, MLKL, and lysosomal membrane permeabilization. In summary, our study demonstrated that RIP1/RIP3 complex-triggered cytosolic calcium

  20. SPRAY CALCINATION REACTOR

    Science.gov (United States)

    Johnson, B.M.

    1963-08-20

    A spray calcination reactor for calcining reprocessin- g waste solutions is described. Coaxial within the outer shell of the reactor is a shorter inner shell having heated walls and with open regions above and below. When the solution is sprayed into the irner shell droplets are entrained by a current of gas that moves downwardly within the inner shell and upwardly between it and the outer shell, and while thus being circulated the droplets are calcined to solids, whlch drop to the bottom without being deposited on the walls. (AEC) H03 H0233412 The average molecular weights of four diallyl phthalate polymer samples extruded from the experimental rheometer were redetermined using the vapor phase osmometer. An amine curing agent is required for obtaining suitable silver- filled epoxy-bonded conductive adhesives. When the curing agent was modified with a 47% polyurethane resin, its effectiveness was hampered. Neither silver nor nickel filler impart a high electrical conductivity to Adiprenebased adhesives. Silver filler was found to perform well in Dow-Corning A-4000 adhesive. Two cascaded hot-wire columns are being used to remove heavy gaseous impurities from methane. This purified gas is being enriched in the concentric tube unit to approximately 20% carbon-13. Studies to count low-level krypton-85 in xenon are continuing. The parameters of the counting technique are being determined. The bismuth isotopes produced in bismuth irradiated for polonium production are being determined. Preliminary data indicate the presence of bismuth207 and bismuth-210m. The light bismuth isotopes are probably produced by (n,xn) reactions bismuth-209. The separation of uranium-234 from plutonium-238 solutions was demonstrated. The bulk of the plutonium is removed by anion exchange, and the remainder is extracted from the uranium by solvent extraction techniques. About 99% of the plutonium can be removed in each thenoyltrifluoroacetone extraction. The viscosity, liquid density, and