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Sample records for azido compounds

  1. Energetic Azido Compounds

    DTIC Science & Technology

    1980-03-28

    Power Program Code 473 Prepared By Chemical Procesaing Unit of Rocketdyne Polymer Unit of Science Center Approvel By H. B. Frankel Manager Chemical ...N4itro Spoxides. 3-Azido-2,2-dinitropropy1 glycidyl ether was prepared by the z~aquence of reactiona shown below: _KOH 1,KOHCHC [C. ’C(NO-7) 2) O1 2 Hh KC...interesting to note that, regardless of the glycerol Scontent, the polymer obtained had essentially the same molecular weight. A possible explanation

  2. Synthesis, characterization, thermal and computational studies of novel tetra-azido compounds as energetic plasticizers

    NASA Astrophysics Data System (ADS)

    Baghersad, Mohammad Hadi; Habibi, Azizollah; Heydari, Akbar

    2017-02-01

    In this paper, four azido compounds have been synthesized and characterized as new energetic plasticizers. Nuclear magnetic resonance (NMR) and infrared (IR) spectroscopy, elemental analysis, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and differential thermal analysis (DTA) have been used to identify and determine the properties of the synthesized plasticizers. The plasticization effect of plasticizers on glycidyl azide polymer (GAP) has been investigated by viscosity measurements and thermal analysis of the prepolymer-plasticizer mixtures and plasticized binders. The plasticized mixtures were cured by a diisocyanate curing agent and the glass transition temperature and decomposition temperature of the cured polyurethane binders were measured. Thermal analysis of the prepolymer-plasticizer and cured polymer mixtures showed that the synthesized plasticizers are completely compatible with the GAP binder and have a very good plasticizing effect. Furthermore, equilibrium geometry and heats of formation of each of the plasticizer molecules were obtained using the thermochemical T1 recipe, which is available in wave function Spartan software. Comparing empirical heats of combustion and calculated heats of combustion by using the heats of formation showed that the suggested optimum molecular structure by the T1 recipe has a high similarity to the real molecular structure of these molecules.

  3. Syntheses, structures and magnetisms of copper(II)–azido coordination compounds with p-substituted benzoates as coligands

    SciTech Connect

    Sun, Cuiyu; Yu, Nan; Bu, Huaitian; Sun, Ce; Bu, Huaiyu

    2016-01-15

    Employing p-substituted benzoates with electron-withdrawing/electron-donating groups as coligands, four copper–azido compounds, [Cu{sub 1.5}(p-NO{sub 2}-benzoate)(N{sub 3}){sub 2}(H{sub 2}O)]{sub n} (1), [Cu(p-NO{sub 2}-benzoate)(N{sub 3})(H{sub 2}O)]{sub n} (2), [Cu(p-OH-benzoate)(N{sub 3})(H{sub 2}O)]{sub n}·nH{sub 2}O (3) and [Cu(p-CH{sub 3}-benzoate)(N{sub 3})]{sub n} (4), have been hydrothermally synthesized and structurally charactierized by single crystal X-ray diffraction. Structural analysis reveals that all compounds are composed of mixed EO-azido and syn–syn carboxylato-bridged Cu-N{sub 3}/COO chains. Compound 1 features the alternating triple-bridged (μ-EO-N{sub 3})(μ-COO)(μ-H{sub 2}O) and the double-bridged (EO-N{sub 3}){sub 2} modes. Both of 2 and 3 display the triple-bridged fashion (μ-EO-N{sub 3})(μ-COO)(μ-H{sub 2}O). While 4 exhibits the double-bridged mode (μ-EO-N{sub 3})(μ-COO). Based on hydrogen-bonding interactions, Cu–N{sub 3}/COO chains in 1–3 are further connected to form 3D supramolecular frameworks. As for compound 4, there are not hydrogen-bonding interactions when the p-CH{sub 3} substituted benzoate is employed as coligand. These compounds show intrachain ferromagnetic performance and different bulk properties. Remarkably, 1 features metamagnetism from antiferromagnetism to ferrimagnetism, while 3 reveals long-range ferromagnetic ordering between Cu(II) ions. Magneto-structural correlation has been also investigated. - Graphical abstract: With p-substituted benzoates as coligands, copper–azido compounds were isolated and structrually, magnetically characterized. Magneto-structural correlation has been investigated in detail.

  4. Syntheses, structures and magnetisms of copper(II)-azido coordination compounds with p-substituted benzoates as coligands

    NASA Astrophysics Data System (ADS)

    Sun, Cuiyu; Yu, Nan; Bu, Huaitian; Sun, Ce; Bu, Huaiyu

    2016-01-01

    Employing p-substituted benzoates with electron-withdrawing/electron-donating groups as coligands, four copper-azido compounds, [Cu1.5(p-NO2-benzoate)(N3)2(H2O)]n (1), [Cu(p-NO2-benzoate)(N3)(H2O)]n (2), [Cu(p-OH-benzoate)(N3)(H2O)]n·nH2O (3) and [Cu(p-CH3-benzoate)(N3)]n (4), have been hydrothermally synthesized and structurally charactierized by single crystal X-ray diffraction. Structural analysis reveals that all compounds are composed of mixed EO-azido and syn-syn carboxylato-bridged Cu-N3/COO chains. Compound 1 features the alternating triple-bridged (μ-EO-N3)(μ-COO)(μ-H2O) and the double-bridged (EO-N3)2 modes. Both of 2 and 3 display the triple-bridged fashion (μ-EO-N3)(μ-COO)(μ-H2O). While 4 exhibits the double-bridged mode (μ-EO-N3)(μ-COO). Based on hydrogen-bonding interactions, Cu-N3/COO chains in 1-3 are further connected to form 3D supramolecular frameworks. As for compound 4, there are not hydrogen-bonding interactions when the p-CH3 substituted benzoate is employed as coligand. These compounds show intrachain ferromagnetic performance and different bulk properties. Remarkably, 1 features metamagnetism from antiferromagnetism to ferrimagnetism, while 3 reveals long-range ferromagnetic ordering between Cu(II) ions. Magneto-structural correlation has been also investigated.

  5. Synthesis, structure, and magnetism of three azido-bridged Co2+ compounds with a flexible coligand 1,2-(tetrazole-1-yl)ethane.

    PubMed

    Li, Ru-Yin; Wang, Xin-Yi; Liu, Tao; Xu, Hong-Bin; Zhao, Fei; Wang, Zhe-Ming; Gao, Song

    2008-09-15

    By utilizing suitable coligand endi (1,2-(tetrazole-1-yl)ethane)) with variable conformations, we synthesized three new azido-bridged Co(2+) compounds with molecular formulas Co(endi)(N3)2 (1, 3) and Co(endi)2(N3)2 (2) by tuning the stoichiometric ratio of ligand/metal and the concentration of the solution. All of the compounds have been characterized structurally and magnetically. In all three structures, the azide ions use the end-to-end mode to link the Co(2+) centers to the 1D chain (1) and 2D (4,4) layers (2 and 3). The endi coligands adopt a trans conformation in compound 1 and a gauche conformation in compounds 2 and 3. Linked by bridging endi, the 1D chains in compound 1 and 2D layers in compound 3 are extended, resulting in the final 2D layer for compound 1 and the 3D network for compound 3, whereas in compound 2, the endi acts as only a terminal ligand to separate the 2D layers. Compound 1 consists of dual end-to-end azido-bridged 1D Co(2+) chains that are linked by trans endi into a 2D layer and are further extended to a 3D framework through H bonds. Compound 2 is a 2D (4,4) layer that is connected by end-to-end azido ions. The gauche endi ligands act as terminal ligands to separate the neighboring layers thoroughly. Compound 3 has a (4,4) 2D layer that is similar to that of compound 2, and these layers are further extended to a 3D network through gauche endi. The magnetic investigation shows that compound 3 is antiferromagnetically coupled and compound 2 is a weak ferromagnet with a critical temperature of 22 K, which is quite high compared with that of the previously reported 2D azido-bridged Co(2+) compounds.

  6. Energetic Azido Compounds

    DTIC Science & Technology

    1982-01-27

    Aerojet Strategic Propulsion Co. WestenOffice ohP.O. Box 15699C 1030 East Green Street Sacramento, CA 95813 1Pasadena, CA 91106 P d A 1Dr. V.J. Keenan I...Weapons Center Crane , Indiana 47522 Code R121 White Oak Dr. A. Faulstich 1 Silver Spring, MD 20910 Chief of Naval Technology MAT Code 0716 S~Washington

  7. Experimental and theoretical investigation of a novel mononuclear copper(II) azido compound with tridentate (NNO) Schiff base

    NASA Astrophysics Data System (ADS)

    Karahan, Ahmet; Karabulut, Sedat; Dal, Hakan; Kurtaran, Raif; Leszczynski, Jerzy

    2015-08-01

    The tridentate (NNO) Schiff base (HL), has been prepared by the condensation of 2-(aminomethyl)pyridine with 5-chloro-salicylaldehyde. The mononuclear [N-(2-pyridylmethyl)-3-chloro-salicylaldiminato] (azido) copper(II) complex of general formula [Cu(L)(N3)] (1) has been synthesized by the treatment of HL and CuCl2·2H2O with sodium azide. The ligand and complex have been investigated by various methods including IR, TG-DTA and X-ray diffraction techniques. The complex crystallizes in monoclinic space group P21/c, with unit cell dimensions a = 6.7369(4), b = 11.6058(8), c = 17.1379(11) Å, β = 93.823(2)°. The distorted square-planar Cu(II) ion in complex is chelated by one imino N, one phenolic O and one pyridine N atoms of Schiff base ligand and one N atom of azide ion. The electrochemical behavior of the mononuclear copper azido complex was studied with cyclic voltammetry. Tautomer stability of the ligand and the complex has been determined by molecular modeling techniques. It has been concluded that the HL is more stable than its tautomeric form (THL) both as ligand and complex structures.

  8. A dinuclear end-on azide-bridged copper(II) compound with weak antiferromagnetic interaction - Synthesis, characterization, magnetism and X-ray structure of bis[(μ-azido-κN1)-(azido-κN1)(1,3-bis(benzimidazol-2-yl)-2-methylpropane)copper(II)

    NASA Astrophysics Data System (ADS)

    van Albada, Gerard A.; Mutikainen, Ilpo; Roubeau, Olivier; Reedijk, Jan

    2013-03-01

    The centrosymmetric dinuclear compound of formula [Cu(μ-N3-κN1)(N3-κN1)(bbmp)]2 is reported. Synthesis, characterization, physical properties are determined in detail, together with its 3D structure. The dinuclear end-on azide-bridged copper(II) compound displays a weak antiferromagnetic interaction, despite the fact that the magnetic orbitals overlap. The Cu-Cu contact distance is 3.1867(8) Å, while the Cu-Nazide-Cu angle is 103.41(14)°. The IR spectra of the azido ligands are as expected for such coordinated azides.

  9. Investigation of reactions postulated to occur during inhibition of ribonucleotide reductases by 2'-azido-2'-deoxynucleotides.

    PubMed

    Dang, Thao P; Sobczak, Adam J; Mebel, Alexander M; Chatgilialoglu, Chryssostomos; Wnuk, Stanislaw F

    2012-07-08

    Model 3'-azido-3'-deoxynucleosides with thiol or vicinal dithiol substituents at C2' or C5' were synthesized to study reactions postulated to occur during inhibition of ribonucleotide reductases by 2'-azido-2'-deoxynucleotides. Esterification of 5'-(tert-butyldiphenylsilyl)-3'-azido-3'-deoxyadenosine and 3'-azido-3'-deoxythymidine (AZT) with 2,3-S-isopropylidene-2,3-dimercaptopropanoic acid or N-Boc-S-trityl-L-cysteine and deprotection gave 3'-azido-3'-deoxy-2'-O-(2,3-dimercaptopropanoyl or cysteinyl)adenosine and the 3'-azido-3'-deoxy-5'-O-(2,3-dimercaptopropanoyl or cysteinyl)thymidine analogs. Density functional calculations predicted that intramolecular reactions between generated thiyl radicals and an azido group on such model compounds would be exothermic by 33.6-41.2 kcal/mol and have low energy barriers of 10.4-13.5 kcal/mol. Reduction of the azido group occurred to give 3'-amino-3'-deoxythymidine, which was postulated to occur with thiyl radicals generated by treatment of 3'-azido-3'-deoxy-5'-O-(2,3-dimercaptopropanoyl)thymidine with 2,2'-azobis-(2-methyl-2-propionamidine) dihydrochloride. Gamma radiolysis of N(2)O-saturated aqueous solutions of AZT and cysteine produced 3'-amino-3'-deoxythymidine and thymine most likely by both radical and ionic processes.

  10. Optimized syntheses of Fmoc azido amino acids for the preparation of azidopeptides.

    PubMed

    Pícha, Jan; Buděšínský, Miloš; Macháčková, Kateřina; Collinsová, Michaela; Jiráček, Jiří

    2017-03-01

    The rise of CuI-catalyzed click chemistry has initiated an increased demand for azido and alkyne derivatives of amino acid as precursors for the synthesis of clicked peptides. However, the use of azido and alkyne amino acids in peptide chemistry is complicated by their high cost. For this reason, we investigated the possibility of the in-house preparation of a set of five Fmoc azido amino acids: β-azido l-alanine and d-alanine, γ-azido l-homoalanine, δ-azido l-ornithine and ω-azido l-lysine. We investigated several reaction pathways described in the literature, suggested several improvements and proposed several alternative routes for the synthesis of these compounds in high purity. Here, we demonstrate that multigram quantities of these Fmoc azido amino acids can be prepared within a week or two and at user-friendly costs. We also incorporated these azido amino acids into several model tripeptides, and we observed the formation of a new elimination product of the azido moiety upon conditions of prolonged couplings with 2-(1H-benzotriazol-1-yl)-1,1,3,3-tetramethyluronium hexafluorophosphate/DIPEA. We hope that our detailed synthetic protocols will inspire some peptide chemists to prepare these Fmoc azido acids in their laboratories and will assist them in avoiding the too extensive costs of azidopeptide syntheses. Experimental procedures and/or analytical data for compounds 3-5, 20, 25, 26, 30 and 43-47 are provided in the supporting information. © 2017 The Authors Journal of Peptide Science published by European Peptide Society and John Wiley & Sons Ltd. © 2017 The Authors Journal of Peptide Science published by European Peptide Society and John Wiley & Sons Ltd.

  11. Optimized syntheses of Fmoc azido amino acids for the preparation of azidopeptides

    PubMed Central

    Pícha, Jan; Buděšínský, Miloš; Macháčková, Kateřina; Collinsová, Michaela

    2017-01-01

    The rise of CuI‐catalyzed click chemistry has initiated an increased demand for azido and alkyne derivatives of amino acid as precursors for the synthesis of clicked peptides. However, the use of azido and alkyne amino acids in peptide chemistry is complicated by their high cost. For this reason, we investigated the possibility of the in‐house preparation of a set of five Fmoc azido amino acids: β‐azido l‐alanine and d‐alanine, γ‐azido l‐homoalanine, δ‐azido l‐ornithine and ω‐azido l‐lysine. We investigated several reaction pathways described in the literature, suggested several improvements and proposed several alternative routes for the synthesis of these compounds in high purity. Here, we demonstrate that multigram quantities of these Fmoc azido amino acids can be prepared within a week or two and at user‐friendly costs. We also incorporated these azido amino acids into several model tripeptides, and we observed the formation of a new elimination product of the azido moiety upon conditions of prolonged couplings with 2‐(1H‐benzotriazol‐1‐yl)‐1,1,3,3‐tetramethyluronium hexafluorophosphate/DIPEA. We hope that our detailed synthetic protocols will inspire some peptide chemists to prepare these Fmoc azido acids in their laboratories and will assist them in avoiding the too extensive costs of azidopeptide syntheses. Experimental procedures and/or analytical data for compounds 3–5, 20, 25, 26, 30 and 43–47 are provided in the supporting information. © 2017 The Authors Journal of Peptide Science published by European Peptide Society and John Wiley & Sons Ltd. PMID:28120383

  12. Azido-based propellants

    SciTech Connect

    Sayles, D.C.

    1987-04-07

    This patent describes an azido-based solid propellant composition having an improved burning rate comprising: a high energy plasticizer of tris-1,2,3(bis(1,2-difluoroamino)ethoxy)propane in an amount from about 24 to about 30 weight percent of the propellant composition; a curative and crosslinking agent of 4,5-epoxycyclohexylmethyl 4'5'-epoxycyclohexylcarboxylate in an amount from about 0.75 to about 1.5 weight percent of the propellant composition; a carboranyl burning rate catalyst of carboranyl-methyl propionate in an amount from about 2 to about 6 weight percent of the propellant composition; graphite linters of about 100 micrometers lengths in an amount from about 1 to about 3 weight percent of the propellant composition; aluminum powder in an amount from about 10 to about 12 weight percent of the propellant composition; aluminum flake in an amount from about 0.5 to about 2 weight percent of the propellant composition; ammonium perchlorate of about 0.9 micrometer diameter in an amount from about 46 to about 52 weight percent of the composition; a processing aid of lecithin in an amount from about 0.1 to about 0.2 weight percent of the propellant composition; and a binder of 2-azidoethyl acrylateacrylic acid copolymer in an amount from about 3 to about 8 weight percent of the propellant composition.

  13. New phenoxido-bridged quasi-tetrahedral and rhomboidal [Cu4] compounds bearing μ4-oxido or μ(1,1)-azido ligands: synthesis, chemical reactivity, and magnetic studies.

    PubMed

    Sarkar, Mrinal; Clérac, Rodolphe; Mathonière, Corine; Hearns, Nigel G R; Bertolasi, Valerio; Ray, Debashis

    2011-05-02

    [Cu(2)(μ(4)-O)Cu(2)] and [Cu(2)(μ(1,1)-N(3))(4)Cu(2)] geometrical arrangements are found in a new family of tetranuclear copper(II) complexes: [Cu(4)(μ(4)-O)(μ-cip)(2)Cl(4)] (1), [Cu(4)(μ(4)-O)(μ-cip)(2)(μ(1,3)-O(2)CPh)(4)]·2CH(3)OH (2·2CH(3)OH), and [Cu(4)(μ(1,1)-N(3))(4)(μ-cip)(2)(N(3))(2)]·DMF (3·DMF) [Hcip = 2,6-bis(cyclohexyliminomethylene)-4-methylphenol; CH(3)OH = methanol; DMF = dimethylformamide]. These complexes have been characterized by X-ray crystallography, and their magnetic properties have been studied. 1 and 2 form quasi-tetrahedral [Cu(4)(μ(4)-O)] complexes, and 3 is the first example of a rhomboidal [Cu(4)(μ(1,1)-N(3))] compound. Formation of the [Cu(4)] compounds is achieved via ligand-exchange reactions. The relative binding strength of the three ancillary ligands as N(3)(-) > PhCO(2)(-) > Cl(-) has been demonstrated from the core-conversion and peripheral ligand-exchange reactions. For the three complexes, the magnetic susceptibility measurements in the range of 1.8-300 K have been performed and modeled using two isolated S = (1)/(2) dimers based on the spin Hamiltonian H = -2J{S(Cu,1)·S(Cu,2)} with J/k(B) = -513, -340, and -315 K for 1-3, respectively (where J is the exchange constant through the oxido-phenoxido and azido-phenoxido bridges, respectively). © 2011 American Chemical Society

  14. Synthesis of polyhydroxylated 2H-azirines and 2-halo-2H-azirines from 3-azido-2,3-dideoxyhexopyranoses by alkoxyl radical fragmentation.

    PubMed

    Alonso-Cruz, Carmen R; Kennedy, Alan R; Rodríguez, María S; Suárez, Ernesto

    2008-06-06

    The reaction of 3-azido-2,3-dideoxypyranose and 3-azido-2,3-dideoxy-2-halohexopyranose compounds with (diacetoxyiodo)benzene and iodine generated 2-azido-1,2-dideoxy-1-iodoalditols and 2-azido-1,2-dideoxy-1-halo-1-iodoalditols, respectively. These beta-iodo azides could be transformed by chemoselective dehydroiodination into 2-azido-1,2-dideoxy-4- O-formyl-pent-1-enitols and (Z, E)-2-azido-1,2-dideoxy-1-halo-4- O-formyl-pent-1-enitols in good yields. Thermolysis and photochemical studies of these vinyl azides and 1-halovinyl azides for the synthesis of polyhydroxylated 3-alkyl-2 H-azirines and the hitherto unknown 2-halo-3-alkyl-2 H-azirines have also been accomplished.

  15. Photoaffinity labeling of the dopamine reuptake carrier protein with 3-azido sup 3 H GBR-12935

    SciTech Connect

    Berger, S.P.; Martenson, R.E.; Laing, P.; Thurkauf, A.; Decosta, B.; Rice, K.C.; Paul, S.M. )

    1991-04-01

    A high affinity tritiated azido-diphenylpiperazine derivative, 3-azido {sup 3}H GBR-12935, was synthesized as a potential photoaffinity probe of the dopamine transporter. Initially, the reversible binding of 3-azido {sup 3}H GBR-12935 to crude synaptosomal membranes from the rat striatum was characterized. Specific binding was sodium dependent and inhibited by a variety of drugs that are known to potently inhibit dopamine uptake. Other neurotransmitter uptake inhibitors, as well as cis-flupenthixol, a potent inhibitor of {sup 3}H GBR-12935 binding to piperazine binding sites, failed to inhibit specific binding at concentrations of less than or equal to 10 microM. A good correlation was observed between the relative potencies of these drugs in inhibiting dopamine uptake into synaptosomes and in inhibiting specific 3-azido {sup 3}H GBR-12935 binding to rat striatal membranes. These data suggest that 3-azido {sup 3}H GBR-12935, like other diphenylpiperazines such as {sup 3}H GBR-12935 and {sup 3}H GBR-12909, binds primarily to the dopamine transporter under defined assay conditions. After UV photolysis of crude synaptosomal membranes preincubated with 3-azido {sup 3}H GBR-12935 (1-2 nM), a single radiolabeled polypeptide with an apparent molecular mass of 80 kDa was observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and fluorography. Photoincorporation of 3-azido {sup 3}H GBR-12935 into this polypeptide was inhibited selectively by compounds that inhibit the uptake of dopamine and was completely dependent on the presence of Na+. No photolabeled proteins were observed when cerebellar membranes were substituted for striatal membranes. Essentially complete adsorption of the radiolabeled 80-kDa polypeptide to wheat germ agglutinin and elution with N-acetyl-D-glucosamine strongly suggest that the dopamine transporter polypeptide photolabeled by 3-azido {sup 3}H GBR-12935 is glycosylated.

  16. Investigation of reactions postulated to occur during inhibition of ribonucleotide reductases by 2′-azido-2′-deoxynucleotides

    PubMed Central

    Dang, Thao P.; Sobczak, Adam J.; Mebel, Alexander M.; Chatgilialoglu, Chryssostomos; Wnuk, Stanislaw F.

    2012-01-01

    Model 3′-azido-3′-deoxynucleosides with thiol or vicinal dithiol substituents at C2′ or C5′ were synthesized to study reactions postulated to occur during inhibition of ribonucleotide reductases by 2′-azido-2′-deoxynucleotides. Esterification of 5′-(tert-butyldiphenylsilyl)-3′-azido-3′-deoxyadenosine and 3′-azido-3′-deoxythymidine (AZT) with 2,3-S-isopropylidene-2,3-dimercaptopropanoic acid or N-Boc-S-trityl-L-cysteine and deprotection gave 3′-azido-3′-deoxy-2′-O-(2,3-dimercaptopropanoyl or cysteinyl)adenosine and the 3′-azido-3′-deoxy-5′-O-(2,3-dimercaptopropanoyl or cysteinyl)thymidine analogs. Density functional calculations predicted that intramolecular reactions between generated thiyl radicals and an azido group on such model compounds would be exothermic by 33.6-41.2 kcal/mol and have low energy barriers of 10.4-13.5 kcal/mol. Reduction of the azido group occurred to give 3′-amino-3′-deoxythymidine, which was postulated to occur with thiyl radicals generated by treatment of 3′-azido-3′-deoxy-5′-O-(2,3-dimercaptopropanoyl)thymidine with 2,2′-azobis-(2-methyl-2-propionamidine) dihydrochloride. Gamma radiolysis of N2O-saturated aqueous solutions of AZT and cysteine produced 3′-amino-3′-deoxythymidine and thymine most likely by both radical and ionic processes. PMID:22711937

  17. Photoaffinity labeling of serum vitamin D binding protein by 3-deoxy-3-azido-25-hydroxyvitamin D3

    SciTech Connect

    Link, R.P.; Kutner, A.; Schnoes, H.K.; DeLuca, H.F.

    1987-06-30

    3-Deoxy-3-azido-25-hydroxyvitamin D3 was covalently incorporated in the 25-hydroxyvitamin D3 binding site of purified human plasma vitamin D binding protein. Competition experiments showed that 3-deoxy-3-azido-25-hydroxyvitamin D3 and 25-hydroxyvitamin D3 bind at the same site on the protein. Tritiated 3-deoxy-3-azido-25-hydroxyvitamin D3 was synthesized from tritiated 25-hydroxyvitamin D3, retaining the high specific activity of the parent compound. The tritiated azido label bound reversibly to human vitamin D binding protein in the dark and covalently to human vitamin D binding protein after exposure to ultraviolet light. Reversible binding of tritiated 3-deoxy-3-azido-25-hydroxyvitamin D3 was compared to tritiated 25-hydroxyvitamin D3 binding to human vitamin D binding protein. Scatchard analysis of the data indicated equivalent maximum density binding sites with a KD,app of 0.21 nM for 25-hydroxyvitamin D3 and a KD,app of 1.3 nM for the azido derivative. Covalent binding was observed only after exposure to ultraviolet irradiation, with an average of 3% of the reversibly bound label becoming covalently bound to vitamin D binding protein. The covalent binding was reduced 70-80% when 25-hydroxyvitamin D3 was present, indicating strong covalent binding at the vitamin D binding site of the protein. When tritiated 3-deoxy-3-azido-25-hydroxyvitamin D3 was incubated with human plasma in the absence and presence of 25-hydroxyvitamin D3, 12% of the azido derivative was reversibly bound to vitamin D binding protein. After ultraviolet irradiation, four plasma proteins covalently bound the azido label, but vitamin D binding protein was the only protein of the four that was unlabeled in the presence of 25-hydroxyvitamin D3.

  18. 4-Azido-2-pyrimidinone Nucleosides and Related Chemistry.

    PubMed

    Kotra, Lakshmi P.; Wang, PingPing; Bartlett, Michael G.; Shanmuganathan, Kirupa; Xu, Zusheng; Cavalcanti, Sócrates; Newton, M. Gary; Chu, Chung K.

    1997-10-17

    As a part of azide prodrug approach, we synthesized a 4-azido analog of ara-C (4) as a prodrug for ara-C. The compound 4 was obtained from 1-(beta-D-arabinofuranosyl)uracil (1) in three steps. At pH 7.0 and 11.0, a loss of UV absorption of the compound 4 was observed resulting from a transformation that was proved by identifying the transformed product 5 by 1-D, and 2-D NMR as well as tandem mass spectral studies. In NMR studies, changes in the chemical shifts were observed at positions 5, 6, 1', and 2' between the compounds 4 and 5. A molecular peak at m/z 270.1 (MH(+)) was observed in the mass spectra of compounds 4 and the transformed product 5. A fragment at 180.2 was identified to be the compound 6, containing the 6,2'-anhydro linkage of compound 5. The X-ray analysis indicated that compound 4 exists as 1-(beta-D-arabinofuranosyl)tetrazolo[4,5-c]pyrimidin-2-one, with the azide moiety cyclized. To understand if the chemical instability of the nucleoside 4 was due to the arabino configuration of 2'-OH or due to the azido moiety, we also studied 1-(2,3-dideoxy-2-fluoro-beta-D-arabinofuranosyl)tetrazolo[4,5-c]pyrimidin-2-one (11) and 4-azido-1-methyl-2-pyrimidinone (15). At pH 2.0 and 7.0, similar UV profiles were observed for compounds 11 and 15. However, at pH 11.0, lambda(max) shifted slowly to lower wavelength for both compounds 11 and 15. In a separate kinetic study, they were stable at pH 7.4 for up to 2.45 h. From the NMR and high-resolution mass spectral studies, it was concluded that in the presence of ammonium hydroxide, an addition of amine occurred at 6-position of compound 11. Thus, the stability profiles of compounds 4, 11, and 15 were different. The instability and the formation of 2',6-anhydro bond in compound 4 in nonacidic media was due to the presence of 2'-OH in the arabino configuration and probably not due to the azide group.

  19. Crystal structure of 2-azido-1H-imidazole-4,5-di­carbonitrile

    PubMed Central

    Windler, G. Kenneth; Scott, Brian L.; Tomson, Neil C.; Leonard, Philip W.

    2015-01-01

    In the title compound, C5HN7, the nitrile and azido substituents are close to being coplanar with the central ring. Mol­ecules in the crystal are linked via an N—H⋯N hydrogen bond to a nitrile acceptor, forming a chain extending along the c-axis direction. PMID:26396874

  20. Crystal structure of 2-azido-1 H -imidazole-4,5-dicarbonitrile

    DOE PAGES

    Windler, G. Kenneth; Scott, Brian L.; Tomson, Neil C.; ...

    2015-08-06

    We report that in the title compound, C5HN7, the nitrile and azido substituents are close to being coplanar with the central ring. Molecules in the crystal are linked via an N—H...N hydrogen bond to a nitrile acceptor, forming a chain extending along the c-axis direction.

  1. Synthesis and asymmetric resolution of α-azido-peroxides.

    PubMed

    Pramanik, Suman; Ghorai, Prasanta

    2013-08-02

    An unprecedented synthesis of α-azido-peroxides has been developed using an FeCl3-catalyst starting from carbonyl, TMS-azide, and hydroperoxide. Further, a base promoted decomposition of synthesized secondary α-azido-peroxides to provide the corresponding tert-butyl esters has been disclosed. Finally, an asymmetric kinetic resolution of such α-azido-peroxides has also been developed to provide chiral α-azido-peroxides in excellent enantiopurity.

  2. Mn-Catalyzed Highly Efficient Aerobic Oxidative Hydroxyazidation of Olefins: A Direct Approach to β-Azido Alcohols.

    PubMed

    Sun, Xiang; Li, Xinyao; Song, Song; Zhu, Yuchao; Liang, Yu-Feng; Jiao, Ning

    2015-05-13

    An efficient Mn-catalyzed aerobic oxidative hydroxyazidation of olefins for synthesis of β-azido alcohols has been developed. The aerobic oxidative generation of azido radical employing air as the terminal oxidant is disclosed as the key process for this transformation. The reaction is appreciated by its broad substrate scope, inexpensive Mn-catalyst, high efficiency, easy operation under air, and mild conditions at room temperature. This chemistry provides a novel approach to high value-added β-azido alcohols, which are useful precursors of aziridines, β-amino alcohols, and other important N- and O-containing heterocyclic compounds. This chemistry also provides an unexpected approach to azido substituted cyclic peroxy alcohol esters. A DFT calculation indicates that Mn catalyst plays key dual roles as an efficient catalyst for the generation of azido radical and a stabilizer for peroxyl radical intermediate. Further calculation reasonably explains the proposed mechanism for the control of C-C bond cleavage or for the formation of β-azido alcohols.

  3. Crystal structure of 2-azido-1 H -imidazole-4,5-dicarbonitrile

    SciTech Connect

    Windler, G. Kenneth; Scott, Brian L.; Tomson, Neil C.; Leonard, Philip W.

    2015-08-06

    We report that in the title compound, C5HN7, the nitrile and azido substituents are close to being coplanar with the central ring. Molecules in the crystal are linked via an N—H...N hydrogen bond to a nitrile acceptor, forming a chain extending along the c-axis direction.

  4. End-to-end azido-pinned interlocking lanthanide squares.

    PubMed

    Li, Xiao-Lei; Wu, Jianfeng; Zhao, Lang; Shi, Wei; Cheng, Peng; Tang, Jinkui

    2017-03-09

    A rare end-to-end azido-pinned interlocking lanthanide square was self-assembled using a ditopic Schiff-base (H2L) and NaN3 as ligands. Obvious ferromagnetic interaction and a record anisotropy barrier of 152(4) K among lanthanide azido-bridged SMMs in a zero dc field were observed.

  5. Azido Push–Pull Fluorogens Photoactivate to Produce Bright Fluorescent Labels

    PubMed Central

    Lord, Samuel J.; Lee, Hsiao-lu D.; Samuel, Reichel; Weber, Ryan; Liu, Na; Conley, Nicholas R.; Thompson, Michael A.; Twieg, Robert J.; Moerner, W. E.

    2009-01-01

    Dark azido push–pull chromophores have the ability to be photoactivated to produce bright fluorescent labels suitable for single-molecule imaging. Upon illumination, the aryl azide functionality in the fluorogens participates in a photochemical conversion to an aryl amine, thus restoring charge-transfer absorption and fluorescence. Previously, we reported that one compound, DCDHF-V-P-azide, was photoactivatable. Here, we demonstrate that the azide-to-amine photoactivation process is generally applicable to a variety of push–pull chromophores, and we characterize the photophysical parameters including photoconversion quantum yield, photostability, and turn-on ratio. Azido push–pull fluorogens provide a new class of photoactivatable single-molecule probes for fluorescent labeling and super-resolution microscopy. Lastly, we demonstrate that photoactivated push–pull dyes can insert into bonds of nearby biomolecules, simultaneously forming a covalent bond and becoming fluorescent (fluorogenic photoaffinity labeling). PMID:19860443

  6. Selective formation of triplet alkyl nitrenes from photolysis of beta-azido-propiophenone and their reactivity.

    PubMed

    Singh, Pradeep N D; Mandel, Sarah M; Sankaranarayanan, Jagadis; Muthukrishnan, Sivaramakrishnan; Chang, Mingxin; Robinson, Rachel M; Lahti, Paul M; Ault, Bruce S; Gudmundsdóttir, Anna D

    2007-12-26

    Photolysis of beta-azido propiophenone derivatives, 1, with built-in sensitizer units, leads to selective formation of triplet alkyl nitrenes 2 that were detected directly with laser flash photolysis (lambdamax = 325 nm, tau = 27 ms) and ESR spectroscopy (|D/hc| = 1.64 cm-1, |E/hc| = 0.004 cm-1). Nitrenes 2 were further characterized with argon matrix isolation, isotope labeling, and molecular modeling. The triplet alkyl nitrenes are persistent intermediates that do not abstract H-atoms from the solvent but do decay by dimerizing with another triplet nitrene to form azo products, rather than reacting with an azide precursor. The azo dimer tautomerizes and rearranges to form heterocyclic compound 3. Nitrene 2a, with an n,pi* configuration as the lowest triplet excited state of the its ketone sensitizer moiety, undergoes intramolecular 1,4-H-atom abstraction to form biradical 6, which was identified by argon matrix isolation, isotope labeling, and molecular modeling. beta-Azido-p-methoxy-propiophenone, with a pi,pi* lowest excited state of its triplet sensitizer moiety, does not undergo any secondary photoreactions but selectively yields only triplet alkyl nitrene intermediates that dimerize to form 3b.

  7. Activities of 3'-azido-3'-deoxythymidine nucleotide dimers in primary lymphocytes infected with human immunodeficiency virus type 1.

    PubMed Central

    Schinazi, R F; Sommadossi, J P; Saalmann, V; Cannon, D L; Xie, M Y; Hart, G C; Smith, G A; Hahn, E F

    1990-01-01

    The relative antiviral potencies of five nucleotide heterodimers of 3'-azido-3'-deoxythymidine (AZT), 3'-azido-3'-deoxythymidilyl-(5',5')-2'-3'-dideoxy-5'-adenylic acid (AZT-P-ddA), 3'-azido-3'-deoxythymidilyl-(5',5')-2',3'-dideoxy-5'-inosinic acid (AZT-P-ddI), and the corresponding 2-cyanoethyl congeners AZT-P(CyE)-ddA and AZT-P(CyE)-ddI, were determined in primary human peripheral blood mononuclear cells infected with human immunodeficiency virus type 1. The homodimer 3'-azido-3'-deoxythymidilyl-(5',5')-3'-azido-3'-deoxythymidilic acid (AZT-P-AZT) was also included for comparison. The potencies of the compounds were AZT-P-ddA greater than or equal to AZT-P-ddI greater than AZT-P(CyE)-ddA greater than or equal to AZT-P(CyE)-ddI greater than or equal to AZT greater than AZT-P-AZT. Whereas AZT-P-ddA and AZT-P-ddI had in vitro therapeutic indices greater than that of AZT, the homodimer of AZT had a low therapeutic index. AZT-P-ddI exhibited the lowest toxicity in peripheral blood mononuclear, Vero, or CEM cells. Combination studies between AZT and 2',3'-dideoxyinosine (ddI) at nontoxic concentrations indicated a synergistic interaction at a drug ratio of 1:100. At higher ratios (1:500 and 1:1,000), the interactions were synergistic only at concentrations that produced up to 75% virus inhibition. At higher levels of antiviral effects, this combination was antagonistic, as determined by the multiple drug effect analysis method. AZT-P-ddI was about 10-fold less toxic than AZT to human granulocyte-macrophage progenitor cells. However, no significant difference was apparent when the compounds were evaluated against cells of the erythroid lineage. The greater antiviral activity and lower toxicity of this compound could not be attributed to the extracellular decomposition of the dimer in media at physiological temperature and pH. However, in acidic solutions, AZT-P-ddI decomposed in a pH-dependent manner. Advanced preclinical studies with this heterodimer of two clinically

  8. Dicyclo­hexyl­ammonium (S)-2-azido-3-phenyl­propano­ate

    PubMed Central

    Petrik, Sebastian J.; Brown, Christopher L.; Boyd, Sue E.; Healy, Peter C.

    2012-01-01

    The asymmetric unit of the title compound, C12H24N+·C9H8N3O2 −, consists of two dicyclo­hexyl­ammonium cations linked to two (S)-2-azido-3-phenyl­propano­ate anions by four short N—H⋯O hydrogen bonds with N⋯O distances in the range 2.712 (3)–2.765 (3) Å. The dicyclo­hexyl­ammonium cations and the aryl and carboxyl­ate groups of the anion are related by a pseudo-inversion centre, with overall crystallographic inversion symmetry for the structure broken by the chirality of the α-C atoms of the anions. PMID:22807875

  9. Dicyclo-hexyl-ammonium (S)-2-azido-3-phenyl-propano-ate.

    PubMed

    Petrik, Sebastian J; Brown, Christopher L; Boyd, Sue E; Healy, Peter C

    2012-07-01

    The asymmetric unit of the title compound, C(12)H(24)N(+)·C(9)H(8)N(3)O(2) (-), consists of two dicyclo-hexyl-ammonium cations linked to two (S)-2-azido-3-phenyl-propano-ate anions by four short N-H⋯O hydrogen bonds with N⋯O distances in the range 2.712 (3)-2.765 (3) Å. The dicyclo-hexyl-ammonium cations and the aryl and carboxyl-ate groups of the anion are related by a pseudo-inversion centre, with overall crystallographic inversion symmetry for the structure broken by the chirality of the α-C atoms of the anions.

  10. Determination of protolytic equilibria for methyl 3-azido-6-iodo-2,3,6-trideoxy-α- D- arabino-hexopyranoside by ab initio and spectrophotometric methods

    NASA Astrophysics Data System (ADS)

    Dąbrowska, Aleksandra; Makowski, Mariusz; Jacewicz, Dagmara; Chylewska, Agnieszka; Chmurzyński, Lech

    2008-12-01

    UV absorption spectra of methyl 3-azido-6-iodo-2,3,6-trideoxy-α- D- arabino-hexopyranoside were recorded over a wide pH range. On this basis, a relationship between absorbance and pH was plotted, from which deprotonation equilibrium constants of this compound were determined. Further, quantum-mechanical calculations were performed at the ab initio level both in the gas phase by using the Restricted Hartree Fock (RHF), Møller-Plesset (MP2) methods and under consideration of solvation effects within the Polarizable Continuum Model (PCM), which enabled location of preferred protonation and deprotonation centers of this compound. The results provided the basis for discussion of the influence of substituents in the sugar ring on protolytic equilibria occurring in aqueous solutions of 3-azido-2,3-dideoxy sugars.

  11. α-Azido bisphosphonates: synthesis and nucleotide analogues

    PubMed Central

    Chamberlain, Brian T.; Upton, Thomas G.; Kashemirov, Boris A.

    2011-01-01

    The first examples of α-azido bisphosphonates [(RO)2P(O)]2CX(N3) (1, R = i-Pr, X = Me; 2, R = i-Pr, X = H; 3, R = H, X = Me; 4, R = H, X = H) and corresponding β,γ-CX(N3) dGTP (5–6) and α,β-CX(N3) dATP (7–8) analogues are described. The individual diastereomers of 7 (7a, 7b) were obtained by HPLC separation of the dADP synthetic precursor (14a/b). PMID:21462930

  12. Synthesis and evaluation of sulfonylethyl-containing phosphotriesters of 3'-azido-3'-deoxythymidine as anticancer prodrugs.

    PubMed

    Wang, Jiang; Wang, Yi-Jun; Chen, Zhe-Sheng; Kwon, Chul-Hoon

    2014-11-01

    A series of bis(sulfonylethyl) and mono(sulfonylethyl) phenyl phosphotriesters of zidovudine (3'-azido-3'-deoxythymidine, AZT) were synthesized as potential anticancer prodrugs that liberate AZT monophosphate via nonenzymatic β-elimination mechanism. Stability studies demonstrated that all the synthesized prodrugs spontaneously liberate AZT monophosphate with half-lives in the range of 0.07-278.8h under model physiological conditions in 0.1M phosphate buffer at pH 7.4 and 37 °C. Analogous to aldophosphamide, the elimination rates were accelerated in the presence of reconstituted human plasma under the same conditions. Among the compounds, 3, 4, 8, and 10 were comparable or superior to AZT against five established human cancerous cell lines in vitro. Moreover, the selected compounds were equally sensitive to both the wild-type osteosarcoma 143 B and the thymidine kinase-deficient 143 B/TK(-) cell lines. The findings are consistent with that these compounds deliver AZT monophosphate intracellularly.

  13. Steering the azido-tetrazole equilibrium of 4-azidopyrimidines via substituent variation - implications for drug design and azide-alkyne cycloadditions.

    PubMed

    Thomann, A; Zapp, J; Hutter, M; Empting, M; Hartmann, R W

    2015-11-21

    This paper focuses on an interesting constitutional isomerism called azido-tetrazole equilibrium which is observed in azido-substituted N-heterocycles. We present a systematic investigation of substituent effects on the isomer ratio within a 2-substituted 4-azidopyrimidine model scaffold. NMR- and IR-spectroscopy as well as X-ray crystallography were employed for thorough analysis and characterization of synthesized derivatives. On the basis of this data, we demonstrate the possibility to steer this valence tautomerism towards the isomer of choice by means of substituent variation. We show that the tetrazole form can act as an efficient disguise for the corresponding azido group masking its well known reactivity in azide-alkyne cycloadditions (ACCs). In copper(I)-catalyzed AAC reactions, substituent-stabilized tetrazoles displayed a highly decreased or even abolished reactivity whereas azides and compounds in the equilibrium were directly converted. By use of an acid sensitive derivative, we provide, to our knowledge, the first experimental basis for a possible exploitation of this dynamic isomerism as a pH-dependent azide-protecting motif for selective SPAAC conjugations in aqueous media. Finally, we demonstrate the applicability and efficiency of stabilized tetrazolo[1,5-c]pyrimidines for Fragment-Based Drug Design (FBDD) in the field of quorum sensing inhibitors.

  14. Synthesis and structural characterization of 9-azido-9-borafluorene: monomer and cyclotrimer of a borole azide.

    PubMed

    Biswas, Sunanda; Oppel, Iris M; Bettinger, Holger F

    2010-05-17

    The reaction of 2,2'-dilithiobiphenyl, generated from 2,2'-dibromobiphenyl and n-BuLi, with BCl(3) using n-hexane as solvent provides a high-yielding, simple preparative route to 9-chloro-9-borafluorene 1a. This in turn can be reacted with trimethylsilyl azide to yield 9-azido-9-borafluorene 2. Compound 2 exists as a cyclic trimer in the solid state, but in dichloromethane solution the monomer can coexist with the trimer. Azide 2 is rather unstable both in the solid state and in solution, and it transforms with trace amounts of water and oxygen to the 1,3,5-tris(2-biphenylyl)cyclotriboroxane that was characterized by X-ray diffraction analysis. Addition of pyridine and t-butyl pyridine to azide 2 afford the corresponding pyridine adducts. Compound 1a as well as the Lewis base adducts of 2 have been characterized by multinuclear NMR spectroscopy, and the structures were confirmed by X-ray diffraction analysis. The structural features of azide 2 and the strong Lewis acidity of its boron center have also been investigated by computational chemistry techniques at the MP2 level of theory.

  15. Probing platinum azido complexes by 14N and 15N NMR spectroscopy.

    PubMed

    Farrer, Nicola J; Gierth, Peter; Sadler, Peter J

    2011-10-17

    Metal azido complexes are of general interest due to their high energetic properties, and platinum azido complexes in particular because of their potential as photoactivatable anticancer prodrugs. However, azido ligands are difficult to probe by NMR spectroscopy due to the quadrupolar nature of (14)N and the lack of scalar (1)H coupling to enhance the sensitivity of the less abundant (15)N by using polarisation transfer. In this work, we report (14)N and (15)N NMR spectroscopic studies of cis,trans,cis-[Pt(N(3))(2)(OH)(2)(NH(3))] (1) and trans,trans,trans-[Pt(N(3))(2)(OH)(2)(X)(Y)], where X=Y=NH(3) (2); X=NH(3), Y=py (3) (py=pyridine); X=Y=py (4); and selected Pt(II) precursors. These studies provide the first (15)N NMR data for azido groups in coordination complexes. We discuss one- and three-bond J((15)N,(195)Pt) couplings for azido and am(m)ine ligands. The (14)N(α) (coordinated azido nitrogen) signal in the Pt(IV) azido complexes is extremely broad (W(1/2)≈2124 Hz for 4) in comparison to other metal azido complexes, attributable to a highly asymmetrical electric field gradient at the (14)N(α) atom. Through the use of anti-ringing pulse sequences, the (14)N NMR spectra, which show resolution of the broad (14)N(α) peak, were obtained rapidly (e.g., 1.5 h for 10 mM 4). The linewidths of the (14)N(α) signals correlate with the viscosity of the solvent. For (15) N-enriched samples, it is possible to detect azido (15)N resonances directly, which will allow photoreactions to be followed by 1D (15)N NMR spectroscopy. The T(1) relaxation times for 3 and 4 were in the range 5.7-120 s for (15)N, and 0.9-11.3 ms for (14)N. Analysis of the (1)J((15)N,(195)Pt) coupling constants suggests that an azido ligand has a moderately strong trans influence in octahedral Pt(IV) complexes, within the series 2-pic

  16. One-pot synthesis of oxazolidine-2-thione and thiozolidine-2-thione from sugar azido-alcohols.

    PubMed

    Mishra, Kunj B; Agrahari, Anand K; Tiwari, Vinod K

    2017-10-10

    A controlled and facile synthesis of various glycosyl 1,3-oxazolidine-2-thiones and 1,3- thiozolidine-2-thiones has been accomplished from corresponding sugar azido alcohols utilizing Staudinger reaction (PPh3 and CS2) via isothiocynate route. A series of reactions were performed to investigate the effects of CS2 and PPh3 on the selectivity of product formed. The excessive addition of CS2 with PPh3(1.2 equiv) afforded oxazolidine-2-thione alone, while the solitary addition of PPh3 for 30 min followed by addition of CS2 to the reaction mixture resulted both the products in different ratios, which were successfully isolated using column chromatography (SiO2). Furthermore, synthesis of 1,3-oxathiolan-2-imine from glycosyl epoxide has also been attempted. Structures of all the developed compounds have been elucidated using extensive spectroscopic techniques including IR, NMR and MS analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Photoreactive azido-containing silica nanoparticle/polycation multilayers: durable superhydrophobic coating on cotton fabrics.

    PubMed

    Zhao, Yan; Xu, Zhiguang; Wang, Xungai; Lin, Tong

    2012-04-17

    In this study, we report the functionalization of silica nanoparticles with highly photoreactive phenyl azido groups and their utility as a negatively charged building block for layer-by-layer (LbL) electrostatic assembly to produce a stable silica nanoparticle coating. Azido-terminated silica nanoparticles were prepared by the functionalization of bare silica nanoparticles with 3-aminopropyltrimethoxysilane followed by the reaction with 4-azidobenzoic acid. The azido functionalization was confirmed by FTIR and XPS. Poly(allylamine hydrochloride) was also grafted with phenyl azido groups and used as photoreactive polycations for LbL assembly. For the photoreactive silica nanoparticle/polycation multilayers, UV irradiation can induce the covalent cross-linking within the multilayers as well as the anchoring of the multilayer film onto the organic substrate, through azido photochemical reactions including C-H insertion/abstraction reactions with surrounding molecules and dimerization of azido groups. Our results show that the stability of the silica nanoparticle/polycation multilayer film was greatly improved after UV irradiation. Combined with a fluoroalkylsilane post-treatment, the photoreactive LbL multilayers were used as a coating for superhydrophobic modification of cotton fabrics. Herein the LbL assembly method enables us to tailor the number of the coated silica nanoparticles through the assembly cycles. The superhydrophobicity of cotton fabrics was durable against acids, bases, and organic solvents, as well as repeated machine wash. Because of the unique azido photochemistry, the approach used here to anchor silica nanoparticles is applicable to almost any organic substrate. © 2012 American Chemical Society

  18. A new route to bicyclo[1.1.1]pentan-1-amine from 1-azido-3-iodobicyclo[1.1.1]pentane.

    PubMed

    Goh, Yi Ling; Tam, Eric K W; Bernardo, Paul H; Cheong, Choon Boon; Johannes, Charles W; William, Anthony D; Adsool, Vikrant A

    2014-04-04

    From a medicinal chemistry perspective, bicyclo[1.1.1]pentan-1-amine (1) has served as a unique and important moiety. Synthetically, however, this compound has received little attention, and only one scalable route to this amine has been demonstrated. Reduction of an easily available and potentially versatile intermediate, 1-azido-3-iodobicyclo[1.1.1]pentane (2), can offer both a flexible and scalable alternative to this target. Herein, we describe our scrutiny of this reportedly elusive transformation and report our ensuing success with this endeavor.

  19. 3-Azido-3-deoxy-glycopyranoside derivatives as scaffolds for the synthesis of carbohydrate-based universal pharmacophore mapping libraries.

    PubMed

    Jain, Rakesh; Kamau, Muthoni; Wang, Chunguang; Ippolito, Robert; Wang, Huiming; Dulina, Richard; Anderson, Jan; Gange, David; Sofia, Michael J

    2003-07-07

    The regiospecific syntheses of six monosaccharide scaffolds, 1-6, containing a carboxylic acid, an azido and a free hydroxyl group were accomplished through the utilization of a key intermediate, namely, methyl 3-azido-3-deoxy-beta-D-glucopyranoside (10). Scaffold 2 was also used in generating combinatorial libraries using solid-phase methodologies.

  20. Photolabeling of mitochondrial F1-H+ATPase by 2-azido[3H]ADP and 8-azido[3H]ADP entrapped as fluorometal complexes into the catalytic sites of the enzyme.

    PubMed

    Garin, J; Vinçon, M; Gagnon, J; Vignais, P

    1994-03-29

    In the presence of ADP and fluorometals, the ATPase activity of the catalytic sector, F1, of beef heart mitochondrial ATPase is strongly inhibited; this inhibition is dependent on the entrapment of ADP-fluoroaluminate complexes into the nucleotide binding sites of F1 [Lunardi, J., Dupuis, A., Garin, J., Issartel, J. P., Michel, L., Chabre, M., & Vignais, P. V. (1988) Proc. Natl. Acad. Sci. U.S.A. 85, 8958-8962]. We described here the effect of fluoroaluminate on the binding of 2-azido[3H]ADP and 8-azido[3H]ADP to beef heart mitochondrial F1 in the absence and presence of light. When the incubation medium was supplemented with NaF and AlCl3, and maintained in the dark, both 2-azido[3H]ADP and 8-azido[3H]ADP were able to elicit inhibition of F1-ATPase activity, exactly like ADP did. Upon photoirradiation, 2-azido[3H]ADP and 8-azido[3H]ADP bound covalently to F1. Labeling was restricted to the beta subunit of F1, and the same tyrosine residue, beta-Tyr-345, was labeled by either of the photoprobes. This is in contrast with the previous findings that in the absence of fluoroaluminate both the alpha and beta subunits of F1 were photolabeled by 8-azido[3H]ADP, and that two different regions of the beta subunits were labeled, centered on beta-Tyr-345 in the case of 2-azido[3H]ADP [Garin, J., Boulay, F., Issartel, J.P., Lunardi, J., & Vignais, P. V. (1986) Biochemistry 25, 4431-4437] and beta-Tyr-311 that of 8-azido[3H]ADP [Hollemans, M., Runswick, M., Fearnley, I.H., & Walker, J.E. (1983) J. Biol. Chem. 258, 9307-9313].(ABSTRACT TRUNCATED AT 250 WORDS)

  1. Synthesis of azido-functionalized carbohydrates for the design of glycoconjugates.

    PubMed

    Cecioni, Samy; Goyard, David; Praly, Jean-Pierre; Vidal, Sébastien

    2012-01-01

    As carbohydrates play a major role in numerous biological processes through their interactions with lectins and also appear as one of the most crucial post-translational modifications of proteins, chemists have developed several approaches for the design of glycoconjugates based on a series of conjugation methodologies. The recent development of copper(I)-catalyzed azide-alkyne cycloaddition (CuACC) paved the way to a novel conjugation strategy in which azido-functionalized carbohydrate derivatives can be readily connected to alkyne-functionalized (bio)molecules. This so-called "click chemistry" methodology has now found numerous applications both in chemistry and biology. The azido moiety can be introduced either directly at the anomeric carbon of the carbohydrate derivative, or attached to a spacer arm. We describe here the syntheses of 2,3,4,6-tetra-O-acetyl-β-D: -glucopyranosyl azide as well as 1-azido-3,6-dioxaoct-8-yl 2,3,4,6-tetra-O-acetyl-β-D: -galactopyranoside and 1-azido-3,6-dioxaoct-8-yl 2,3,6,2',3',4',6'-hepta-O-acetyl-β-D: -lactoside. These molecules can then be used in the construction of glycoconjugates to find applications in chemical biology.

  2. Two and 8-azido photoaffinity probes. 1. Enzymatic synthesis, characterization, and biological properties of 2- and 8-azido photoprobes of 2-5A and photolabeling of 2-5A binding proteins

    SciTech Connect

    Suhadolnik, R.J.; Kariko, K.; Sobol, R.W. Jr.; Li, S.W.; Reichenbach, N.L.; Haley, B.E.

    1988-11-29

    The 2- and 8-azido trimer 5'-triphosphate photoprobes of 2-5A have been enzymatically synthesized from (..gamma..-/sup 32/P)2-azidoATP and (..cap alpha..-/sup 32/P)8-azidoAPT by 2-5A synthetase from rabbit reticulocyte lysates. Identification and structural determination of the 2- and 8-azido adenylate trimer 5'-triphosphates were accomplished by enzymatic hydrolyses with T2 RNase, snake venom phosphodiesterase, and bacterial alkaline phosphatase. Hydrolysis products were identified by HPLC and PEI-cellulose TLC analyses. The 8-azido photoprobe of 2-5A displaces p/sub 3/A/sub 4/(/sup 32/P)pCp from RNase L with affinity equivalent to p/sub 3/A/sub 3/. The 8-azido photoprobe also activates RNase L to hydrolyze poly(U)(/sup 32/P)pCp 50% at 7 /times/ 10/sup /minus/9/ M in core-cellulose assays. The 2- and 8-azido photoprobes and authentic p/sub 3/A/sub 3/ activate RNase L to cleave 28S and 18S rRNA to specific cleavage products at 10/sup /minus/9/ M in rRNA cleavage assays. The nucleotide binding site(s) of RNase L and/or other 2-5A binding proteins in extracts of interferon-treated L929 cells were investigated by photoaffinity labeling. Dramatically different photolabeling patterns were observed with the 2- and 8-azido photoprobes. The (..gamma..-/sup 32/P)2-azido adenylate trimer 5'-triphosphate photolabels only one polypeptide with a molecular weight of 185,000 as determined by SDS gel electrophoresis, whereas the (..cap alpha..-/sup 32/P)8-azido adenylate trimer 5'-triphosphate covalently photolabels six polypeptides with molecular weights of 46,000, 63,000, 80,000, 89,000, 109,000, and 158,000. Evidence that the photolabeling by 2- and 8-azido 2-5A photoprobes was highly specific for the p/sub 3/A/sub 3/ allosteric binding site was obtained.

  3. A novel dinuclear bismuth(III) coordination compound: bis(μ-pyridine-2,6-dicarboxylato)-κ4O2,N,O6:O6′;κ4O2:O2′,N,O6-bis[(azido-κN)(1,10-phenanthroline-κ2N,N')bismuth(III)] tetrahydrate.

    PubMed

    Zhang, Wei; Feng, Yu-Quan

    2014-06-01

    A novel dinuclear bismuth(III) coordination compound, [Bi2(C7H3NO4)2(N3)2(C12H8N2)2]·4H2O, has been synthesized by an ionothermal method and characterized by elemental analysis, energy-dispersive X-ray spectroscopy, IR, X-ray photoelectron spectroscopy and single-crystal X-ray diffraction. The molecular structure consists of one centrosymmetric dinuclear neutral fragment and four water molecules. Within the dinuclear fragment, each Bi(III) centre is seven-coordinated by three O atoms and four N atoms. The coordination geometry of each Bi(III) atom is distorted pentagonal-bipyramidal (BiO3N4), with one azide N atom and one bridging carboxylate O atom located in axial positions. The carboxylate O atoms and water molecules are assembled via O-H···O hydrogen bonds, resulting in the formation of a three-dimensional supramolecular structure. Two types of π-π stacking interactions are found, with centroid-to-centroid distances of 3.461 (4) and 3.641 (4) Å.

  4. Tuning reactivity of glycosyl imidinium intermediate for 2-azido-2-deoxyglycosyl donors in α-glycosidic bond formation.

    PubMed

    Ingle, Arun B; Chao, Chin-Sheng; Hung, Wei-Cheng; Mong, Kwok-Kong Tony

    2013-10-18

    The chemical properties of nucleophile additives were investigated in a modulated glycosylation context. N-Formylmorpholine (NFM) was found to be an effective modulator for glycosylation with less reactive 2-azido-2-deoxythioglucosyl and thiogalactosyl donors.

  5. Synthesis, antiviral activity, cytotoxicity and cellular pharmacology of l-3′-azido-2′,3′-dideoxypurine nucleosides

    PubMed Central

    Zhang, Hong-wang; Detorio, Mervi; Herman, Brian D.; Solomon, Sarah; Bassit, Leda; Nettles, James H.; Obikhod, Aleksandr; Tao, Si-jia; Mellors, John W.; Sluis-Cremer, Nicolas; Coats, Steven J.; Schinazi, Raymond F.

    2011-01-01

    Microwave-assisted optimized transglycosylation reactions were used to prepare eleven modified l-3′-azido-2′,3′-dideoxypurine nucleosides. These l-nucleoside analogs were evaluated against HIV and hepatitis B virus. The l-3′-azido-2′,3′-dideoxypurines nucleosides were metabolized to nucleoside 5′-triphosphates in primary human lymphocytes, but exhibited weak or no antiviral activity against HIV-1. The nucleosides were also inactive against HBV in HepG2 cells. Pre-steady-state kinetic experiments demonstrated that the l-3′-azido-2′,3′-dideoxypurine triphosphates could be incorporated by purified HIV-1 reverse transcriptase, although their catalytic efficiency (kpol/Kd) of incorporation was low. Interestingly, a phosphoramidate prodrug of l-3′-azido-2′,3′-dideoxyadenosine exhibited anti-HIV-1 activity without significant toxicity. PMID:21700368

  6. Direct imaging of glycans in Arabidopsis roots via click labeling of metabolically incorporated azido-monosaccharides.

    PubMed

    Hoogenboom, Jorin; Berghuis, Nathalja; Cramer, Dario; Geurts, Rene; Zuilhof, Han; Wennekes, Tom

    2016-10-10

    Carbohydrates, also called glycans, play a crucial but not fully understood role in plant health and development. The non-template driven formation of glycans makes it impossible to image them in vivo with genetically encoded fluorescent tags and related molecular biology approaches. A solution to this problem is the use of tailor-made glycan analogs that are metabolically incorporated by the plant into its glycans. These metabolically incorporated probes can be visualized, but techniques documented so far use toxic copper-catalyzed labeling. To further expand our knowledge of plant glycobiology by direct imaging of its glycans via this method, there is need for novel click-compatible glycan analogs for plants that can be bioorthogonally labelled via copper-free techniques. Arabidopsis seedlings were incubated with azido-containing monosaccharide analogs of N-acetylglucosamine, N-acetylgalactosamine, L-fucose, and L-arabinofuranose. These azido-monosaccharides were metabolically incorporated in plant cell wall glycans of Arabidopsis seedlings. Control experiments indicated active metabolic incorporation of the azido-monosaccharide analogs into glycans rather than through non-specific absorption of the glycan analogs onto the plant cell wall. Successful copper-free labeling reactions were performed, namely an inverse-electron demand Diels-Alder cycloaddition reaction using an incorporated N-acetylglucosamine analog, and a strain-promoted azide-alkyne click reaction. All evaluated azido-monosaccharide analogs were observed to be non-toxic at the used concentrations under normal growth conditions. Our results for the metabolic incorporation and fluorescent labeling of these azido-monosaccharide analogs expand the possibilities for studying plant glycans by direct imaging. Overall we successfully evaluated five azido-monosaccharide analogs for their ability to be metabolically incorporated in Arabidopsis roots and their imaging after fluorescent labeling. This expands

  7. Substrate mimicry: HIV-1 reverse transcriptase recognizes 6-modified-3'-azido-2',3'-dideoxyguanosine-5'-triphosphates as adenosine analogs.

    PubMed

    Herman, Brian D; Schinazi, Raymond F; Zhang, Hong-wang; Nettles, James H; Stanton, Richard; Detorio, Mervi; Obikhod, Aleksandr; Pradère, Ugo; Coats, Steven J; Mellors, John W; Sluis-Cremer, Nicolas

    2012-01-01

    β-D-3'-Azido-2',3'-dideoxyguanosine (3'-azido-ddG) is a potent inhibitor of HIV-1 replication with a superior resistance profile to zidovudine. Recently, we identified five novel 6-modified-3'-azido-ddG analogs that exhibit similar or superior anti-HIV-1 activity compared to 3'-azido-ddG in primary cells. To gain insight into their structure-activity-resistance relationships, we synthesized their triphosphate (TP) forms and assessed their ability to inhibit HIV-1 reverse transcriptase (RT). Steady-state and pre-steady-state kinetic experiments show that the 6-modified-3'-azido-ddGTP analogs act as adenosine rather than guanosine mimetics in DNA synthesis reactions. The order of potency of the TP analogs against wild-type RT was: 3'-azido-2,6-diaminopurine >3'-azido-6-chloropurine; 3'-azido-6-N-allylaminopurine > 2-amino-6-N,N-dimethylaminopurine; 2-amino-6-methoxypurine. Molecular modeling studies reveal unique hydrogen-bonding interactions between the nucleotide analogs and the template thymine base in the active site of RT. Surprisingly, the structure-activity relationship of the analogs differed in HIV-1 RT ATP-mediated excision assays of their monophosphate forms, suggesting that it may be possible to rationally design a modified base analog that is efficiently incorporated by RT but serves as a poor substrate for ATP-mediated excision reactions. Overall, these studies identify a promising strategy to design novel nucleoside analogs that exert profound antiviral activity against both WT and drug-resistant HIV-1.

  8. Compound

    NASA Astrophysics Data System (ADS)

    Suzumura, Akitoshi; Watanabe, Masaki; Nagasako, Naoyuki; Asahi, Ryoji

    2014-06-01

    Recently, Cu-based chalcogenides such as Cu3SbSe4, Cu2Se, and Cu2SnSe3 have attracted much attention because of their high thermoelectric performance and their common feature of very low thermal conductivity. However, for practical use, materials without toxic elements such as selenium are preferable. In this paper, we report Se-free Cu3SbS4 thermoelectric material and improvement of its figure of merit ( ZT) by chemical substitutions. Substitutions of 3 at.% Ag for Cu and 2 at.% Ge for Sb lead to significant reductions in the thermal conductivity by 37% and 22%, respectively. These substitutions do not sacrifice the power factor, thus resulting in enhancement of the ZT value. The sensitivity of the thermal conductivity to chemical substitutions in these compounds is discussed in terms of the calculated phonon dispersion and previously proposed models for Cu-based chalcogenides. To improve the power factor, we optimize the hole carrier concentration by substitution of Ge for Sb, achieving a power factor of 16 μW/cm K2 at 573 K, which is better than the best reported for Se-based Cu3SbSe4 compounds.

  9. Synthesis of an azido-tagged low affinity ratiometric calcium sensor

    PubMed Central

    Caldwell, Stuart T.; Cairns, Andrew G.; Olson, Marnie; Chalmers, Susan; Sandison, Mairi; Mullen, William; McCarron, John G.; Hartley, Richard C.

    2015-01-01

    Changes in high localised concentrations of Ca2+ ions are fundamental to cell signalling. The synthesis of a dual excitation, ratiometric calcium ion sensor with a Kd of 90 μM, is described. It is tagged with an azido group for bioconjugation, and absorbs in the blue/green and emits in the red region of the visible spectrum with a large Stokes shift. The binding modulating nitro group is introduced to the BAPTA core prior to construction of a benzofuran-2-yl carboxaldehyde by an allylation–oxidation–cyclisation sequence, which is followed by condensation with an azido-tagged thiohydantoin. The thiohydantoin unit has to be protected with an acetoxymethyl (AM) caging group to allow CuAAC click reaction and incorporation of the KDEL peptide endoplasmic reticulum (ER) retention sequence. PMID:26709317

  10. X-ray analysis of azido-thymidine diphosphate binding to nucleoside diphosphate kinase

    PubMed Central

    Xu, Yingwu; Sellam, Olivier; Moréra, Solange; Sarfati, Simon; Biondi, Ricardo; Véron, Michel; Janin, Joël

    1997-01-01

    To be effective as antiviral agent, AZT (3′-azido-3′-deoxythymidine) must be converted to a triphosphate derivative by cellular kinases. The conversion is inefficient and, to understand why AZT diphosphate is a poor substrate of nucleoside diphosphate (NDP) kinase, we determined a 2.3-Å x-ray structure of a complex with the N119A point mutant of Dictyostelium NDP kinase. It shows that the analog binds at the same site and, except for the sugar ring pucker which is different, binds in the same way as the natural substrate thymidine diphosphate. However, the azido group that replaces the 3′OH of the deoxyribose in AZT displaces a lysine side chain involved in catalysis. Moreover, it is unable to make an internal hydrogen bond to the oxygen bridging the β- and γ-phosphate, which plays an important part in phosphate transfer. PMID:9207061

  11. X-ray analysis of azido-thymidine diphosphate binding to nucleoside diphosphate kinase.

    PubMed

    Xu, Y; Sellam, O; Moréra, S; Sarfati, S; Biondi, R; Véron, M; Janin, J

    1997-07-08

    To be effective as antiviral agent, AZT (3'-azido-3'-deoxythymidine) must be converted to a triphosphate derivative by cellular kinases. The conversion is inefficient and, to understand why AZT diphosphate is a poor substrate of nucleoside diphosphate (NDP) kinase, we determined a 2.3-A x-ray structure of a complex with the N119A point mutant of Dictyostelium NDP kinase. It shows that the analog binds at the same site and, except for the sugar ring pucker which is different, binds in the same way as the natural substrate thymidine diphosphate. However, the azido group that replaces the 3'OH of the deoxyribose in AZT displaces a lysine side chain involved in catalysis. Moreover, it is unable to make an internal hydrogen bond to the oxygen bridging the beta- and gamma-phosphate, which plays an important part in phosphate transfer.

  12. Stereoselective Bioreduction of α-Azido Ketones by Whole Cells of Marine-Derived Fungi.

    PubMed

    Rocha, Lenilson C; Seleghim, Mirna H R; Comasseto, João V; Sette, Lara D; Porto, André L M

    2015-12-01

    Seven strains of marine-derived fungi (Aspergillus sclerotiorum CBMAI 849, Cladosporium cladosporioides CBMAI 857, Penicillium raistrickii CBMAI 931, Penicillium citrinum CBMA 1186, Mucor racemosus CBMAI 847, Beauveria felina CBMAI 738, and Penicillium oxalicum CBMAI 1185) and terrestrial fungus Penicillium chrysogenum CBMA1199 were screened as catalysts for the asymmetric reduction of α-keto azides 5-8 to their corresponding β-azidophenylethanols 9-12. The marine fungi showed Prelog and anti-Prelog selectivities to the reduction α-keto azides 5-8. The fungi A. sclerotiorum CBMAI 849, C. cladosporioides CBMAI 857, P. raistrickii CBMAI 931, and P. citrinum CBMA 1186 catalyzed the reduction of azido ketone 6 to the corresponding (R)-2-azido-1-(4-methoxyphenyl)ethanol (10) with good conversions (68-100 %) and excellent enantiomeric excesses (>99 % ee) according to Prelog rule.

  13. Biotransformation in various species and in humans of 3'-azido-3'-deoxythymidine, a potential agent for the treatment of AIDS

    SciTech Connect

    Good, S.S.; Durack, D.T.; de Miranda, P.

    1986-03-01

    The metabolic fate of 3'-azido-3'-deoxythymidine (AZT), a potent in vitro inhibitor of HTLV-III and several other retroviruses, has been investigated in various species and man. When /sup 3/H-AZT was administered to rats, mice and a guinea pig, most of the dose was recovered in the urine as unchanged drug (61-83%). No metabolism of AZT was observed in the rabbit or the cat. However, extensive biotransformation of AZT occurred in the monkey and man. More metabolite than parent drug was recovered in the urine of Cynomolgus monkeys following i.v. dosing. The mean urinary recoveries of parent compound and of metabolite from AIDS patients receiving AZT were, respectively, 22 and 57% following i.v. dosing (n=7) and 18 and 72% following oral dosing (n=4). The metabolite was isolated from the urine of a patient treated with AZT and characterized using physical and biochemical methods as 5'-glucuronly-AZT (GAZT). GAZT was formed in vitro when human liver microsomes were incubated with AZT and UDPglucuronic acid. The enzyme which mediates the formation of GAZT is probably the microsomal enzyme, UDPglucuronyl transferase.

  14. Catalytic transformation of esters of 1,2-azido alcohols into α-amido ketones.

    PubMed

    Kim, Yongjin; Pak, Han Kyu; Rhee, Young Ho; Park, Jaiwook

    2016-05-05

    The esters of 1,2-azido alcohols were transformed into α-amido ketones without external oxidants through the Ru-catalyzed formation of N-H imines with the liberation of N2 followed by intramolecular migration of the acyl moiety. A wide range of α-amido ketones were obtained, and one-pot transformation into the corresponding oxazoles (or a thiazole) was demonstrated.

  15. Synthesis, molecular structure and physicochemical properties of bis(3‧-azido-3‧-deoxythymidin-5‧-yl) carbonate

    NASA Astrophysics Data System (ADS)

    Raviolo, Mónica A.; Williams, Patricia A. M.; Etcheverry, Susana B.; Piro, Oscar E.; Castellano, Eduardo E.; Gualdesi, Maria S.; Briñón, Margarita C.

    2010-04-01

    3'-Azido-3'-deoxythymidine (zidovudine, AZT), a synthetic analog of natural nucleoside thymidine, has been used extensively in AIDS treatments. We report here the synthesis, X-ray crystal and molecular structure, NMR, IR and Raman spectra and the thermal behavior of a novel carbonate of AZT [(AZT-O) 2C dbnd O], prepared by the reaction of zidovudine with carbonyldiimidazole. The carbonate compound, C 21H 24N 10O 9, crystallizes in the tetragonal space group P4 12 12 with a = b = 15.284(1), c = 21.695(1) Å, and Z = 8 molecules per unit cell. It consists of two AZT moieties of closely related conformations which are bridged by a carbonyl group to adopt a folded Z-like shape.

  16. 2-[4-(Azido-meth-yl)phen-yl]benzonitrile.

    PubMed

    Peng, Bo

    2012-07-01

    The title compound, C(14)H(10)N(4), was obtained by a reaction of 4'-(bromo-meth-yl)biphenyl-2-carbonitrile and sodium azide. The dihedral angle between the benzene rings is 46.41 (7)°. Weak inter-molecular C-H⋯π inter-actions occur in the crystal.

  17. Synthesis of sugar-based silica gels by copper-catalysed azide-alkyne cycloaddition via a single-step azido-activated silica intermediate and the use of the gels in hydrophilic interaction chromatography.

    PubMed

    Moni, Lisa; Ciogli, Alessia; D'Acquarica, Ilaria; Dondoni, Alessandro; Gasparrini, Francesco; Marra, Alberto

    2010-05-17

    Novel sugar-based silica gels were prepared by exploiting the copper-catalysed azide-alkyne cycloaddition (CuAAC) of two different sugar alkynes, namely, ethynyl C-galactoside 1 and propargyl O-lactoside 2, with new single-step azido-activated silica gels. The fully characterised stationary phases were generally used for hydrophilic interaction chromatography (HILIC), with particular application in the stereoselective separation of monosaccharides. Dynamic HILIC (DHILIC) experiments were performed to evaluate the influence of mutarotation on the chromatographic peak shapes of two interconverting sugar anomers. The potential of such materials was shown in the separation of other highly polar compounds, including amino acids and flavonoids.

  18. 2′-Azido RNA, a Versatile Tool for Chemical Biology: Synthesis, X-ray Structure, siRNA Applications, Click Labeling

    PubMed Central

    2012-01-01

    Chemical modification can significantly enrich the structural and functional repertoire of ribonucleic acids and endow them with new outstanding properties. Here, we report the syntheses of novel 2′-azido cytidine and 2′-azido guanosine building blocks and demonstrate their efficient site-specific incorporation into RNA by mastering the synthetic challenge of using phosphoramidite chemistry in the presence of azido groups. Our study includes the detailed characterization of 2′-azido nucleoside containing RNA using UV-melting profile analysis and CD and NMR spectroscopy. Importantly, the X-ray crystallographic analysis of 2′-azido uridine and 2′-azido adenosine modified RNAs reveals crucial structural details of this modification within an A-form double helical environment. The 2′-azido group supports the C3′-endo ribose conformation and shows distinct water-bridged hydrogen bonding patterns in the minor groove. Additionally, siRNA induced silencing of the brain acid soluble protein (BASP1) encoding gene in chicken fibroblasts demonstrated that 2′-azido modifications are well tolerated in the guide strand, even directly at the cleavage site. Furthermore, the 2′-azido modifications are compatible with 2′-fluoro and/or 2′-O-methyl modifications to achieve siRNAs of rich modification patterns and tunable properties, such as increased nuclease resistance or additional chemical reactivity. The latter was demonstrated by the utilization of the 2′-azido groups for bioorthogonal Click reactions that allows efficient fluorescent labeling of the RNA. In summary, the present comprehensive investigation on site-specifically modified 2′-azido RNA including all four nucleosides provides a basic rationale behind the physico- and biochemical properties of this flexible and thus far neglected type of RNA modification. PMID:22273279

  19. A one-dimensional azido-bridged manganese(III) complex with bidentate Schiff base: Crystal structure and magnetic properties

    SciTech Connect

    Li Wei; Li Zongwei; Li Licun Liao Daizheng; Jiang Zonghui

    2007-10-15

    The synthesis, structural characterization, and magnetic behavior of a novel one-dimensional azido-bridged manganese(III) complex of formula [Mn(L){sub 2}N{sub 3}] (1) is reported, where HL is the bidentate Schiff base obtained from the condensation of salicylaldehyde with 4-methoxy aniline. Complex 1 crystallizes in the monoclinic system, space group P2{sub 1}/n, with a=11.743(4) A, b=24.986(9) A, c=13.081(5) A, {beta}=95.387(7){sup o} and Z=2. The complex is of one-dimensional chain structure with single end-to-end azido bridges and the manganese(III) ion has an elongated octahedral geometry. Magnetic studies show that the weak antiferromagnetic interaction is mediated by the single end-to-end azido bridge with the exchange parameter J=-5.84 cm{sup -1}. - Graphical abstract: A novel azido-bridged manganese(III) complex with bidentate Schiff base ligands has been prepared and characterized structurally and magnetically. The complex is of one-dimensional chain structure with single end-to-end azido bridges in axial positions. Two bidentate Schiff base ligands coordinate in the equatorial mode. The magnetic measurements show that the complex exhibits weak antiferromagnetic interaction.

  20. Synthesis and characterization of nano-scale of a new azido Co(II) complex as single and nano-scale crystals: Bithiazole precursor for the preparation of Co3O4 nano-structures

    NASA Astrophysics Data System (ADS)

    Hosseinian, Akram; Jabbari, Sahand; Rahimipour, Hamid Reza; Mahjoub, Ali Reza

    2012-11-01

    Nano-scale and single crystals of a new azido Co(II) complex, {[Co(DADMBTZ)2(N3)2]ṡ0.25CH3OH} (1), {DADMBTZ = 2,2'-diamino-5,5'-dimethyl-4,4'-bithiazole} have been synthesized by the reaction of cobalt chloride, sodium azide and DADMBTZ using sonochemical and heat gradient methods, respectively. The new nanoparticles were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and FT-IR spectroscopy. Complex (1) was structurally characterized by single crystal X-ray diffraction. The coordination number of cobalt atom in the compound is six with coordinated environments of distorted octahedral, CoN6. In reaction with DADMBTZ, the ligand DADMBTZ acts as bidentate in complex to form five-membered chelate rings with different internal angles in coordination polyhedron. Two monodentate azido ions occupy the cis position. The crystal packing is mainly stabilized by Nsbnd H⋯N hydrogen bonding interactions. The thermal stability of compound (1) was studied by thermal gravimetric (TG) and differential thermal analyses (DTA). Co3O4 nanostructures were obtained by direct thermolyses of compound (1) at 450 °C under air atmosphere. The Co3O4 nanoparticles were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy.

  1. Diazo Compounds: Versatile Tools for Chemical Biology.

    PubMed

    Mix, Kalie A; Aronoff, Matthew R; Raines, Ronald T

    2016-12-16

    Diazo groups have broad and tunable reactivity. That and other attributes endow diazo compounds with the potential to be valuable reagents for chemical biologists. The presence of diazo groups in natural products underscores their metabolic stability and anticipates their utility in a biological context. The chemoselectivity of diazo groups, even in the presence of azido groups, presents many opportunities. Already, diazo compounds have served as chemical probes and elicited novel modifications of proteins and nucleic acids. Here, we review advances that have facilitated the chemical synthesis of diazo compounds, and we highlight applications of diazo compounds in the detection and modification of biomolecules.

  2. Rational design of novel anti-microtubule agent (9-azido-noscapine) from quantitative structure activity relationship (QSAR) evaluation of noscapinoids.

    PubMed

    Santoshi, Seneha; Naik, Pradeep K; Joshi, Harish C

    2011-10-01

    An anticough medicine, noscapine [(S)-3-((R)4-methoxy-6-methyl-5,6,7,8-tetrahydro-[1,3]dioxolo[4,5-g]isoquinolin-5-yl)-6,7-dimethoxyiso-benzofuran-1(3H)-one], was discovered in the authors' laboratory as a novel type of tubulin-binding agent that mitigates polymerization dynamics of microtubule polymers without changing overall subunit-polymer equilibrium. To obtain systematic insight into the relationship between the structural framework of noscapine scaffold and its antitumor activity, the authors synthesized strategic derivatives (including two new ones in this article). The IC(50) values of these analogs vary from 1.2 to 56.0 µM in human acute lymphoblastic leukemia cells (CEM). Geometrical optimization was performed using semiempirical quantum chemical calculations at the 3-21G* level. Structures were in agreement with nuclear magnetic resonance analysis of molecular flexibility in solution and crystal structures. A genetic function approximation algorithm of variable selection was used to generate the quantitative structure activity relationship (QSAR) model. The robustness of the QSAR model (R(2) = 0.942) was analyzed by values of the internal cross-validated regression coefficient (R(2) (LOO) = 0.815) for the training set and determination coefficient (R(2) (test) = 0.817) for the test set. Validation was achieved by rational design of further novel and potent antitumor noscapinoid, 9-azido-noscapine, and reduced 9-azido-noscapine. The experimentally determined value of pIC(50) for both the compounds (5.585 M) turned out to be very close to predicted pIC(50) (5.731 and 5.710 M).

  3. Co(III)(salen)-catalyzed HKR of two stereocentered alkoxy- and azido epoxides: a concise enantioselective synthesis of (S,S)-reboxetine and (+)-epi-cytoxazone.

    PubMed

    Reddy, R Santhosh; Chouthaiwale, Pandurang V; Suryavanshi, Gurunath; Chavan, Vilas B; Sudalai, Arumugam

    2010-07-21

    The HKR of racemic syn- or anti- alkoxy- and azido epoxides catalyzed by Co(salen) complex affords a practical access to a series of enantioenriched syn- or anti- alkoxy- and azido epoxides and the corresponding 1,2-diols. This strategy has been successfully employed in the concise, enantioselective synthesis of bioactive molecules such as (S,S)-reboxetine and (+)-epi-cytoxazone.

  4. Ortho-stabilized 18F-azido click agents and application in PET imaging of single-stranded DNA aptamer

    PubMed Central

    Wang, Lu; Jacobson, Orit; Avdic, Din; Rotstein, Benjamin H.; Weiss, Ido D.; Collier, Lee

    2015-01-01

    Azido 18F-arenes are important and versatile building blocks for radiolabeling of biomolecules via Huisgen cycloaddition (‘click chemistry’) in positron emission tomography (PET). However, routine access of such clickable agents is challenged by inefficient multi-step and esoteric radiochemical approaches. Herein we describe a high-yielding direct radiofluorination for azido 18F-arenes by developing an oxygen ortho-stabilized iodonium derivative (OID). This OID strategy addresses an unmet need for a reliable azido 18F-arene clickable agent in bioconjugation reactions. A ssDNA aptamer is radiolabeled and visualized in a xenograft mouse model of human colon cancer by PET, which demonstrates a convenient and highly efficient way of labeling biomolecules and tracking them by OID approach. PMID:26308650

  5. Photocleavage of DNA and photofootprinting of E. coli RNA polymerase bound to promoter DNA by azido-9-acridinylamines.

    PubMed Central

    Jeppesen, C; Buchardt, O; Henriksen, U; Nielsen, P E

    1988-01-01

    The long-wavelength ultraviolet (lambda approximately 420 nm) radiation induced reaction between 6-azido-2-methoxy-9-acridinylamines and supercoiled plasmid DNA results in single strand scissions and formation of covalent adducts (ratio approximately 1:10). By treating azidoacridine-photomodified DNA with piperidine at 90 degrees C, additional strand scissions are observed in a complex sequence dependent manner with an overall preference for T greater than or equal to G greater than C much greater than A. The resulting DNA fragments migrate as 5'-phosphates in polyacrylamide gels. Photofootprinting of the binding site of RNA-polymerase on promoter DNA is demonstrated with an azido-9-acridinylamino-octamethylene-9-aminoacridine. Similar experiments using 9-amino-6-azido-2-methoxyacridine indicate that this reagent recognizes changes in the DNA conformation induced by RNA polymerase binding, in relation to open complex formation. Images PMID:3041368

  6. Synthesis of γ-azido-β-ureido ketones and their transformation into functionalized pyrrolines and pyrroles via Staudinger/aza-Wittig reaction.

    PubMed

    Fesenko, Anastasia A; Shutalev, Anatoly D

    2013-02-01

    A simple two-step procedure yielding γ-azido-β-ureido ketones or/and their cyclic isomers, 6-(1-azidoalkyl)-4-hydroxyhexahydropyrimidin-2-ones, has been developed. The synthesis includes three-component condensation of acetals of 2-azidoaldehydes with urea or methylurea and p-toluenesulfinic acid in aqueous formic acid followed by reaction of the obtained N-[(2-azido-1-tosyl)alkyl]ureas with sodium enolates of α-functionalized ketones. The azido ketones or their cyclic isomers are transformed into ureido-substituted Δ(1)- or/and Δ(2)-pyrrolines via Staudinger/aza-Wittig reaction promoted by PPh(3). The obtained pyrrolines are converted into 3-functionalized 1H-pyrroles via elimination of urea under acidic conditions. Convenient one-pot syntheses of 1H-pyrroles starting from N-[(2-azido-1-tosyl)alkyl]ureas or γ-azido-β-ureido ketones have been also developed.

  7. N-[Amino-(azido)-meth-ylidene]-4-methyl-benzene-sulfonamide.

    PubMed

    Mahmood, Ayyaz; Khan, Islam Ullah; Arshad, Muhammad Nadeem; Ahmed, Jamil

    2011-08-01

    In the title mol-ecule, C(8)H(10)N(5)O(2)S, the amino-(azido)-methyl and p-toluene-sulfonyl moieties are inclined almost at right angles with respect to each other, making a dihedral angle of 83.49 (6)°. An intra-molecular N-H⋯O hydrogen bond gives rise to the formation of six-membered ring with graph-set motif S(6). In the crystal, inter-molecular N-H⋯O hydrogen bonding is responsible for the formation of dimers about inversion centers, which are linked through another N-H⋯O inter-action along the b axis.

  8. Specific photoaffinity labeling of two plasma membrane polypeptides with an azido auxin

    SciTech Connect

    Hicks, G.R.; Rayle, D.L.; Jones, A.M.; Lomax, T.L. )

    1989-07-01

    Plasma membrane vesicles were isolated from zucchini (Cucurbita pepo) hypocotyl tissue by aqueous phase partitioning and assessed for homogeneity by the use of membrane-specific enzyme assays. The highly pure plasma membrane vesicles maintained a pH differential across the membrane and accumulated a tritiated azido analogue of 3-indoleacetic acid (IAA), 5-azido-(7-{sup 3}H)IAA(({sup 3}H)N{sub 3}IAA), in a manner similar to the accumulation of ({sup 3}H)IAA. The association of the ({sup 3}H)N{sub 3}IAA with membrane vesicles was saturable and subject to competition by IAA and auxin analogues. Auxin-binding proteins were photoaffinity labeled by addition of ({sup 3}H)N{sub 3}IAA to plasma membrane vesicles prior to exposure to UV light and detected by subsequent NaDodSO{sub 4}/PAGE and fluorography. When the reaction temperature was lowered to {minus}196{degree}C, high-specific-activity labeling of a 40-kDa and a 42-kDa polypeptide was observed. Collectively, these results suggest that the radiolabeled polypeptides are auxin receptors. The covalent nature of the label should facilitate purification and further characterization of the receptors.

  9. Inactivation of B/sub 12/-dependent ribonucleotide reductase by 2'-azido-2'-deoxyarabinofuranosyladenine 5'-triphosphate

    SciTech Connect

    Ashley, G.W.; Stubbe, J.

    1986-05-01

    The Coenzyme B/sub 12/-dependent ribonucleotide triphosphate reductase (RTPR) from Lactobacillus leichmannii is rapidly inactivated by the substrate analog 2-azido-2'-deoxy-arabinofuranosyladenine 5'-triphosphate (N/sub 3/araATP). This reaction has been probed using N/sub 2/ araATP specifically radiolabeled in the sugar and base moieties. Unlike the inactivation of this enzyme by 2'-halo nucleotides, reaction of RTPR with N/sub 3/araATP does not result in formation of PPPi, adenine, or azide ion. Instead, the phosphate, sugar, and base moieties remain bound to the protein after gel filtration of the inactive protein. One equivalent of coenzyme is destroyed during the inactivation, producing 5'-deoxyadenosine and cob(II)alamin. No/sup 3/H/sub 2/O is formed when RTPR is inactivated with (3'-/sup 3/H)N/sub 3/araATP. These results suggest that inactivation occurs either through reaction of an enzyme group with the azido moiety or through formation of a tight-binding product.

  10. Synthesis of new 2′-deoxy-2′-fluoro-4′-azido nucleoside analogues as potent anti-HIV agents

    PubMed Central

    Wang, Qiang; Hu, Weidong; Wang, Shuyang; Pan, Zhenliang; Tao, Le; Guo, Xiaohe; Qian, Keduo; Chen, Chin-Ho; Lee, Kuo-Hsiung; Chang, Junbiao

    2011-01-01

    We prepared 1-(4′-azido-2′-deoxy-2′-fluoro-β -D-arabinofuranosyl)cytosine (10) and its hydrochloride salt (11) as potential antiviral agents based on the favorable antiviral profiles of 4′-substituted nucleosides. Compounds 10 and 11 were synthesized from 1,3,5-O-tribenzoyl-2-deoxy-2-fluoro-D-arabinofuranoside in multiple steps, and their structures were unequivocally established by IR, 1H NMR, 13C NMR, and 19F NMR spectroscopy, HRMS, and X-ray crystallography. Compounds 10 and 11 exhibited potent anti-HIV-1 activity (EC50: 0.3 and 0.13 nM, respectively) without significant cytotoxicity in concentrations up to 100 μM. Compound 11 exhibited extremely potent anti-HIV activity against NL4-3 (wild-type), NL4-3 (K101E), and RTMDR viral strains, with EC50 values of 0.086, 0.15, and 0.11 nM, respectively. Due to the high potency of 11, it was also screened against an NIH Reagent Program NRTI-resistant virus panel containing eleven mutated viral strains and for cytotoxicity against six different human cell lines. The results of this screening indicated that 11 is a novel NRTI that could be developed as an anti-AIDS clinical trial candidate to overcome drug-resistance issues. PMID:21745701

  11. Lipase-catalyzed synthesis of azido-functionalized aliphatic polyesters towards acid-degradable amphiphilic graft copolymers.

    PubMed

    Wu, Wan-Xia; Wang, Na; Liu, Bei-Yu; Deng, Qing-Feng; Yu, Xiao-Qi

    2014-02-28

    A series of novel aliphatic polyesters with azido functional groups were synthesized via the direct lipase-catalyzed polycondensation of dialkyl diester, diol and 2-azido-1,3-propanediol (azido glycerol) using immobilized lipase B from Candida antarctica (CALB). The effects of polymerization conditions including reaction time, temperature, enzyme amount, substrates and monomer feed ratio on the molecular weights of the products were studied. The polyesters with pendant azido groups were characterized by (1)H NMR, (13)C NMR, 2D NMR, FTIR, GPC and DSC. Alkyne end-functionalized poly(ethylene glycol) containing a cleavable acetal group was then grafted onto the polyester backbone by copper-catalyzed azide-alkyne cycloaddition (CuAAC, click chemistry). Using fluorescence spectroscopy, dynamic light scattering (DLS) and transmission electron microscopy (TEM), these amphiphilic graft copolymers were found to readily self-assemble into nanosized micelles in aqueous solution with critical micelle concentrations between 0.70 and 1.97 mg L(-1), and micelle sizes from 20-70 nm. The degradation of these polymers under acidic conditions was investigated by GPC and (1)H NMR spectroscopy. Cell cytotoxicity tests indicated that the micelles had no apparent cytotoxicity to Bel-7402 cells, suggesting their potential as carriers for controlled drug delivery.

  12. Synthesis and site-directed fluorescence labeling of azido proteins using eukaryotic cell-free orthogonal translation systems.

    PubMed

    Quast, Robert B; Claussnitzer, Iris; Merk, Helmut; Kubick, Stefan; Gerrits, Michael

    2014-04-15

    Eukaryotic cell-free systems based on wheat germ and Spodoptera frugiperda insect cells were equipped with an orthogonal amber suppressor tRNA-synthetase pair to synthesize proteins with a site-specifically incorporated p-azido-l-phenylalanine residue in order to provide their chemoselective fluorescence labeling with azide-reactive dyes by Staudinger ligation. The specificity of incorporation and bioorthogonality of labeling within complex reaction mixtures was shown by means of translation and fluorescence detection of two model proteins: β-glucuronidase and erythropoietin. The latter contained the azido amino acid in proximity to a signal peptide for membrane translocation into endogenous microsomal vesicles of the insect cell-based system. The results indicate a stoichiometric incorporation of the azido amino acid at the desired position within the proteins. Moreover, the compatibility of cotranslational protein translocation, including glycosylation and amber suppression-based incorporation of p-azido-l-phenylalanine within a cell-free system, is demonstrated. The presented approach should be particularly useful for providing eukaryotic and membrane-associated proteins for investigation by fluorescence-based techniques.

  13. Dimerization of propargyl and homopropargyl 6-azido-6-deoxy-glycosides upon 1,3-dipolar cycloaddition

    PubMed Central

    Pietrzik, Nikolas; Schmollinger, Daniel

    2008-01-01

    Summary Copper-catalyzed, thermal or microwave promoted 1,3-dipolar cycloaddition (Click Reaction) of 2-propynyl and 3-butynyl 2,3,4-tri-O-acetyl-6-azido-6-deoxy-glycopyranosides in the D-gluco, D-galacto and D-manno series afford the corresponding dimeric cycloaddition products. PMID:18941499

  14. Two ferromagnetic azido-bridged copper(II) complexes studied by first-principle electronic-structure calculation

    NASA Astrophysics Data System (ADS)

    Zhang, Y. S.; Yao, K. L.; Liu, Z. L.

    2005-09-01

    The electronic structures of two ferromagnetic polynuclear copper(II) complexes, derived from end-to-end azido ligand and tridentate (NNN donor) Schiff base ligand, have been studied using the full-potential linearized augmented plane-wave method based on the density-functional theory. They are [Cu(L1)(μ-1,3-N3)]n(ClO4)n (1) and [Cu(L2)(μ-1,3-N3)]n(ClO4)n (2). The result shows that the spin populations in these two complexes are mainly distributed on the equatorial planes of a square pyramidal that surround the copper(II) ions. There are large and positive spin populations on copper(II) ions, small and positive spin populations on the three nitrogen atoms of tridentate Schiff base ligand, and the two terminal nitrogen atoms of asymmetrical end-to-end azido ligand, while weak and negative spin populations on the central nitrogen atoms of asymmetrical end-to-end azido ligand. Ferromagnetic coupling through the asymmetrical azido ligand in these two complexes has been mainly attributed to the spin delocalization, also with weak spin-polarization effect.

  15. Preparation of carbon nanoparticles and carbon nitride from high nitrogen compound

    DOEpatents

    Huynh, My Hang V [Los Alamos, NM; Hiskey, Michael A [Los Alamos, NM

    2009-09-01

    The high-nitrogen compound 3,6-di(azido)-1,2,4,5-tetrazine (DiAT) was synthesized by a relatively simple method and used as a precursor for the preparation of carbon nanospheres and nanopolygons, and nitrogen-rich carbon nitrides.

  16. Activities of (-)-carbovir and 3'-azido-3'-deoxythymidine against human immunodeficiency virus in vitro.

    PubMed Central

    Carter, S G; Kessler, J A; Rankin, C D

    1990-01-01

    (-)-Carbovir, the minus optical isomer of carbocyclic-2',3'-didehydro-2',3'-dideoxyguanosine, has been shown to be the biologically active form for the inhibition of human immunodeficiency virus type 1 replication. The concentration of (-)-carbovir required to reduce reverse transcriptase activity by 50% compared with the control was 0.8 microM in H9 cells infected with the HTLV-IIIb strain; the 50% inhibitory concentration for cytotoxicity was greater than 2 mM in these cells. The effect of the timing of drug addition, pre- and postinfection, and the effect of increasing amounts of virus on the antiviral activities of (-)-carbovir and 3'-azido-3'-deoxythymidine were determined. PMID:2393292

  17. Detection of an azido-(/sup 14/C)-atrazine labeled protein transferred to nitrocellulose paper

    SciTech Connect

    Ivey, S.; Metz, J.G.; Berg, S.P.

    1986-04-01

    An electrophoretically similar protein in spinach and maize can be covalently labeled with azido-(/sup 14/C)-atrazine and separated by 10-18% gradient LDS-PAGE. The protein profile can be transferred to nitrocellulose paper (ncp) by western blotting. The ncp containing the protein profile is sliced into 2 mm slices and counted with liquid scintillation. The labeled protein migrates as a diffuse band with a Mr of 34 kD. This band migrates at a higher Mr (40 kD) under different gel conditions. The ncp dissolves in the organic scintillation cocktail thus providing a more sensitive and quantitative detection of the /sup 14/C. This technique allows the simultaneous immunological and radiochemical identification of many electrophoretically separable proteins.

  18. The metabolism of 3'-azido-2',3'-dideoxyguanosine in CEM cells

    SciTech Connect

    Karlsson, A.; Reichard, P.; Eckstein, F. )

    1990-01-15

    When CEM cells were incubated with ({sup 3}H)-labeled 3'-azido-2',3'-dideoxyguanosine (AzddGuo), the isotope was largely recovered as ribo- and deoxyribonucleotides in the acid soluble fraction of CEM cells, due to extensive catabolism of AzddGuo and recycling of the guanine formed by purine nucleoside phosphorylase. Only 10% was found as the AzddGuo nucleotides, with the diphosphate of AzddGuo as the dominating nucleotide at all time points. Thus nucleoside diphosphate kinase was rate limiting for the formation of AzddGuo triphosphate, responsible for the toxic and antiviral activity of the nucleoside. Inhibition of de novo deoxyribonucleotide synthesis with hydroxyurea increased the phosphorylation of AzddGuo twofold.

  19. Molecular structure of mononuclear azido- and dicyanamido-Cu(II) complexes

    NASA Astrophysics Data System (ADS)

    Mautner, Franz A.; Landry, Christine N.; Gallo, August A.; Massoud, Salah S.

    2007-06-01

    A new series of mononuclear azido- and dicyanamido-Cu(II) complexes, [Cu(L)(N 3)]ClO 4 where L = pdpa { N-(2-aminopropyl)- N, N-bis(2-pyridylmethyl)amine}, Me 3tren {tris( N-methyl-2-aminoethyl)amine} and Me 6trien (1,1,4,7,10,10-hexamethyltriethylenetetraamine) and Cu(L)(C 2N 3) 2 with L = pmedien ( N, N, N', N″, N″-pentamethyldiethylenetriamine) and Me 2dpt ( N, N-dimethyldipropyltriamine) were synthesized and structurally characterized by electronic and IR spectroscopy as well as by X-ray. Single crystal X-ray diffraction analysis of the complexes [Cu(pdpa)(N 3)]ClO 4 ( 1), [Cu(Me 3tren)(N 3)]ClO 4 ( 2) and [Cu(pmedien)(C 2N 3) 2] ( 3) reveals their monomeric nature. The structures of the complexes 1 and 2 derived from the blocking tripod tetraamines pdpa and Me 3tren consist of isolated [Cu(L)(N 3)] + cations and ClO4- counter ions. The copper centers are penta-coordinated by the four N of the amine ligands with the monodentate azido ligand occupying the apical site in distorted trigonal bipyramidal (TBP) geometry. Complex 1 exhibits π-π stacking interaction between the pyridyl groups. In the neutral complex 3, where the blocking ligand, pmedien is a linear tridentate amine the penta-coordinate geometry of the complex was achieved by the three planar amine- N and two terminal nitrile- N atoms from the two dicyanamide groups; one N in the basal position from the first dicyanamido group and one N at the apical position from the second group. The coordination polyhedron around the copper center may be described as an axially elongated square pyramidal (SP). The visible spectra of the complexes in aqueous solutions are in complete agreement with the assigned X-ray geometry around the Cu(II) centers.

  20. Specific photoaffinity labeling of two plasma membrane polypeptides with an azido auxin

    NASA Technical Reports Server (NTRS)

    Hicks, G. R.; Rayle, D. L.; Jones, A. M.; Lomax, T. L.

    1989-01-01

    Plasma membrane vesicles were isolated from zucchini (Cucurbita pepo) hypocotyl tissue by aqueous phase partitioning and assessed for homogeneity by the use of membrane-specific enzyme assays. The highly pure (ca. 95%) plasma membrane vesicles maintained a pH differential across the membrane and accumulated a tritiated azido analogue of 3-indoleacetic acid (IAA), 5-azido-[7-3H]IAA ([3H]N3IAA), in a manner similar to the accumulation of [3H]IAA. The association of the [3H]N3IAA with membrane vesicles was saturable and subject to competition by IAA and auxin analogues. Auxin-binding proteins were photoaffinity labeled by addition of [3H]N3IAA to plasma membrane vesicles prior to exposure to UV light (15 sec; 300 nm) and detected by subsequent NaDodSO4/PAGE and fluorography. When the reaction temperature was lowered to -196 degrees C, high-specific-activity labeling of a 40-kDa and a 42-kDa polypeptide was observed. Triton X-100 (0.1%) increased the specific activity of labeling and reduced the background, which suggests that the labeled polypeptides are intrinsic membrane proteins. The labeled polypeptides are of low abundance, as expected for auxin receptors. Further, the addition of IAA and auxin analogues to the photoaffinity reaction mixture resulted in reduced labeling that was qualitatively similar to their effects on the accumulation of radiolabeled IAA in membrane vesicles. Collectively, these results suggest that the radiolabeled polypeptides are auxin receptors. The covalent nature of the label should facilitate purification and further characterization of the receptors.

  1. Specific photoaffinity labeling of two plasma membrane polypeptides with an azido auxin

    NASA Technical Reports Server (NTRS)

    Hicks, G. R.; Rayle, D. L.; Jones, A. M.; Lomax, T. L.

    1989-01-01

    Plasma membrane vesicles were isolated from zucchini (Cucurbita pepo) hypocotyl tissue by aqueous phase partitioning and assessed for homogeneity by the use of membrane-specific enzyme assays. The highly pure (ca. 95%) plasma membrane vesicles maintained a pH differential across the membrane and accumulated a tritiated azido analogue of 3-indoleacetic acid (IAA), 5-azido-[7-3H]IAA ([3H]N3IAA), in a manner similar to the accumulation of [3H]IAA. The association of the [3H]N3IAA with membrane vesicles was saturable and subject to competition by IAA and auxin analogues. Auxin-binding proteins were photoaffinity labeled by addition of [3H]N3IAA to plasma membrane vesicles prior to exposure to UV light (15 sec; 300 nm) and detected by subsequent NaDodSO4/PAGE and fluorography. When the reaction temperature was lowered to -196 degrees C, high-specific-activity labeling of a 40-kDa and a 42-kDa polypeptide was observed. Triton X-100 (0.1%) increased the specific activity of labeling and reduced the background, which suggests that the labeled polypeptides are intrinsic membrane proteins. The labeled polypeptides are of low abundance, as expected for auxin receptors. Further, the addition of IAA and auxin analogues to the photoaffinity reaction mixture resulted in reduced labeling that was qualitatively similar to their effects on the accumulation of radiolabeled IAA in membrane vesicles. Collectively, these results suggest that the radiolabeled polypeptides are auxin receptors. The covalent nature of the label should facilitate purification and further characterization of the receptors.

  2. Substrate mimicry: HIV-1 reverse transcriptase recognizes 6-modified-3′-azido-2′,3′-dideoxyguanosine-5′-triphosphates as adenosine analogs

    PubMed Central

    Herman, Brian D.; Schinazi, Raymond F.; Zhang, Hong-wang; Nettles, James H.; Stanton, Richard; Detorio, Mervi; Obikhod, Aleksandr; Pradère, Ugo; Coats, Steven J.; Mellors, John W.; Sluis-Cremer, Nicolas

    2012-01-01

    β-D-3′-Azido-2′,3′-dideoxyguanosine (3′-azido-ddG) is a potent inhibitor of HIV-1 replication with a superior resistance profile to zidovudine. Recently, we identified five novel 6-modified-3′-azido-ddG analogs that exhibit similar or superior anti-HIV-1 activity compared to 3′-azido-ddG in primary cells. To gain insight into their structure–activity–resistance relationships, we synthesized their triphosphate (TP) forms and assessed their ability to inhibit HIV-1 reverse transcriptase (RT). Steady-state and pre-steady-state kinetic experiments show that the 6-modified-3′-azido-ddGTP analogs act as adenosine rather than guanosine mimetics in DNA synthesis reactions. The order of potency of the TP analogs against wild-type RT was: 3′-azido-2,6-diaminopurine >3′-azido-6-chloropurine; 3′-azido-6-N-allylaminopurine > 2-amino-6-N,N-dimethylaminopurine; 2-amino-6-methoxypurine. Molecular modeling studies reveal unique hydrogen-bonding interactions between the nucleotide analogs and the template thymine base in the active site of RT. Surprisingly, the structure–activity relationship of the analogs differed in HIV-1 RT ATP-mediated excision assays of their monophosphate forms, suggesting that it may be possible to rationally design a modified base analog that is efficiently incorporated by RT but serves as a poor substrate for ATP-mediated excision reactions. Overall, these studies identify a promising strategy to design novel nucleoside analogs that exert profound antiviral activity against both WT and drug-resistant HIV-1. PMID:21914723

  3. Synthesis of ferrocene-labeled steroids via copper-catalyzed azide-alkyne cycloaddition. Reactivity difference between 2β-, 6β- and 16β-azido-androstanes.

    PubMed

    Fehér, Klaudia; Balogh, János; Csók, Zsolt; Kégl, Tamás; Kollár, László; Skoda-Földes, Rita

    2012-06-01

    Copper-catalyzed cycloaddition of steroidal azides and ferrocenyl-alkynes were found to be an efficient methodology for the synthesis of ferrocene-labeled steroids. At the same time, a great difference between the reactivity of 2β- or 16β-azido-androstanes and a sterically hindered 6β-azido steroid toward both ferrocenyl-alkynes and simple alkynes, such as phenylacetylene, 1-octyne, propargyl acetate and methyl propiolate, was observed. Copyright © 2012 Elsevier Inc. All rights reserved.

  4. The trans-cis and the azide-tetrazole ring-chain isomerization of 2-azido-1,3-azoles: Quantum chemical study

    NASA Astrophysics Data System (ADS)

    Karakus, Nihat; Demirel, Merdan

    2015-08-01

    Quantum chemical calculations using Density Functional Theory (DFT) at the B3LYP/6-31++G(d,p) basis set level were performed to investigate the azide group rotation from the trans to the cis isomer and the azido-tetrazole ring-chain isomerism equilibrium of 2-azido-1,3-azoles in the gas phase, carbon tetrachloride (CCl4), acetonitrile (CH3CN) and water (H2O). The solvent effect on the relative stabilities of each species was analyzed within the self-consistent field theory using the Polarized Continuum Model (PCM). The transition states (TSs) of each step was identified and confirmed. The azido-tetrazole ring-chain isomerism equilibrium was investigated in detail. In addition, the electronic characteristics of each species were analyzed by means of Molecular Electrostatic Potential (MEP) and Natural Bond Orbital (NBO) analyses. The relative energies were increased with the increasing electronegativity of X atom in the 1,3-azole ring. The study confirmed that the relative stability of the tetrazole isomers could be maximized to a great extent by increasing the polarity of solvent, and vice versa for the azido isomers. The low rotational barrier of the azido group in the trans ⇋ cis isomerization and the significant increase of the dipole moment of the tetrazole isomers were determined factors in ring-chain isomerization. The results obtained in advance for 2-azido-1,3-thiazoles were found to be consistent with the experimental and theoretically data reported.

  5. Studies on the inhibition of sphingosine-1-phosphate lyase by stabilized reaction intermediates and stereodefined azido phosphates.

    PubMed

    Sanllehí, Pol; Abad, José-Luís; Bujons, Jordi; Casas, Josefina; Delgado, Antonio

    2016-11-10

    Two kinds of inhibitors of the PLP-dependent enzyme sphingosine-1-phosphate lyase have been designed and tested on the bacterial (StS1PL) and the human (hS1PL) enzymes. Amino phosphates 1, 12, and 32, mimicking the intermediate aldimines of the catalytic process, were weak inhibitors on both enzyme sources. On the other hand, a series of stereodefined azido phosphates, resulting from the replacement of the amino group of the natural substrates with an azido group, afforded competitive inhibitors in the low micromolar range on both enzyme sources. This similar behavior represents an experimental evidence of the reported structural similarities for both enzymes at their active site level. Interestingly, the anti-isomers of the non-natural enantiomeric series where the most potent inhibitors on hS1PL. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  6. An Azido-Biotin Reagent for Use in the Isolation of Protein Adducts of Lipid-derived Electrophiles by Streptavidin Catch and Photorelease*

    PubMed Central

    Kim, Hye-Young H.; Tallman, Keri A.; Liebler, Daniel C.; Porter, Ned A.

    2009-01-01

    HNE (4-hydroxynonenal), a byproduct of lipid peroxidation, reacts with nucleophilic centers on proteins. A terminal alkynyl analog of HNE (alkynyl HNE, aHNE) serves as a surrogate for HNE itself, both compounds reacting with protein amine and thiol functional groups by similar chemistry. Proteins modified with aHNE undergo reaction with a click reagent that bears azido and biotin groups separated by a photocleavable linker. Peptides and proteins modified in this way are affinity purified on streptavidin beads. Photolysis of the beads with a low intensity UV light releases bound biotinylated proteins or peptides, i.e. proteins or peptides modified by aHNE. Two strategies, (a) protein catch and photorelease and (b) peptide catch and photorelease, are employed to enrich adducted proteins or peptide mixtures highly enriched in adducts. Proteomics analysis of the streptavidin-purified peptides by LC-MS/MS permits identification of the adduction site. Identification of 30 separate peptides from human serum albumin by peptide catch and photorelease reveals 18 different aHNE adduction sites on the protein. Protein catch and photorelease shows that both HSA and ApoA1 in human plasma undergo significant modification by aHNE. PMID:19483245

  7. Crystal structure of ammonium 3'-azido-3'-de-oxy-thymidine-5'-amino-carbonyl-phospho-nate hemi-hydrate: an anti-HIV agent.

    PubMed

    Jasko, Maxim V; Gurskaya, Galina V; Kukhanova, Marina K; Bushmarinov, Ivan S

    2014-11-01

    The asymmetric unit of the title compound, NH4 (+)·C11H14N6O7P(-)·0.5H2O, contains one 3'-azido-3'-de-oxy-thymidine-5'amino-carbonyl-phospho-nate (ACP-AZT) anion, half of an NH4 (+) cation lying on a twofold rotation axis and in another position, occupied with equal probabilities of 0.5, an NH4 (+) cation and a water mol-ecule. The amide group of the ACP-AZT anion is disordered (occupancy ratio 0.5:0.5), with one part forming an N-H⋯O (involving C=O⋯H4N(+)) hydrogen bond and the other an O-H⋯N (involving C-NH2⋯OH2) hydrogen bond with the components of the split NH4 (+)/H2O position. The pseudorotation parameters of ACP-AZT set it apart from previously studied AZT and thymidine. In the crystal, the various components are linked by N-H⋯O, O-H⋯O, N-H⋯N, C-H⋯O and C-H⋯N hydrogen bonds, forming a three-dimensional framework.

  8. Sensitive Photoacoustic IR Spectroscopy for the Characterization of Amino/Azido Mixed-Linker Metal-Organic Frameworks.

    PubMed

    Canivet, Jerome; Lysenko, Vladimir; Lehtinen, Jaakko; Legrand, Alexandre; Wisser, Florian M; Quadrelli, Elsje Alessandra; Farrusseng, David

    2017-08-23

    Photoacoustic Fourier-transform infrared spectroscopy makes it possible to determine the organic composition of mixed-linker metal-organic frameworks. The sound produced upon IR irradiation enables the discrimination of azido and amino linkers in three different MOF platforms with a sensitivity that is two orders of magnitude higher than that achieved using classic IR analysis. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Identification of Protein Targets of 4-Hydroxynonenal Using Click Chemistry for Ex Vivo Biotinylation of Azido and Alkynyl Derivatives

    PubMed Central

    Vila, Andrew; Tallman, Keri A.; Jacobs, Aaron T.; Liebler, Daniel C.; Porter, Ned A.; Marnett, Lawrence J.

    2009-01-01

    Polyunsaturated fatty acids (PUFA) are primary targets of free radical damage during oxidative stress. Diffusible electrophilic α, β-unsaturated aldehydes, such as 4-hydroxynonenal (HNE), have been shown to modify proteins that mediate cell signaling (e.g. IKK and Keap1) and alter gene expression pathways responsible for inducing antioxidant genes, heat shock proteins, and the DNA damage response. To fully understand cellular responses to HNE, it is important to determine its protein targets in an unbiased fashion. This requires a strategy for detecting and isolating HNE-modified proteins regardless of the nature of the chemical linkage between HNE and its targets. Azido or alkynyl derivatives of HNE were synthesized and demonstrated to be equivalent to HNE in their ability to induce heme oxygenase induction and induce apoptosis in colon cancer (RKO) cells. Cells exposed to the tagged HNE derivatives were lysed and exposed to reagents to effect Staudinger ligation or copper-catalyzed Huisgen 1,3 dipolar cycloaddition reaction (click chemistry) to conjugate HNE-adducted proteins with biotin for subsequent affinity purification. Both strategies yielded efficient biotinylation of tagged HNE-protein conjugates but click chemistry was found to be superior for recovery of biotinylated proteins from streptavidin-coated beads. Biotinylated proteins were detected in lysates from RKO cell incubations with azido-HNE at concentrations as low as 1 μM. These proteins were affinity purified with streptavidin beads and proteomic analysis was performed by linear ion trap mass spectrometry. Proteomic analysis revealed a dose-dependent increase in labeled proteins with increased sequence coverage at higher concentrations. Several proteins involved in stress signaling (heat shock proteins 70 and 90, and the 78-kDa glucose-regulated protein) were selectively adducted by azido- and alkynyl-HNE. The use of azido and alkynyl derivatives in conjunction with click chemistry appears to be

  10. 3'-Azido-3'-deoxythymidine inhibits the replication of avian leukosis virus.

    PubMed Central

    Olsen, J C; Furman, P; Fyfe, J A; Swanstrom, R

    1987-01-01

    We tested the ability of the thymidine analog 3'-azido-3'-deoxythymidine (BWA509U) to inhibit the replication of the retrovirus avian leukosis virus. Inhibition was measured with two different assays: inhibition of a single round of virus replication and inhibition of virus spread through a cell culture. With both assays, we detected inhibition of virus growth, although inhibition of a single round of virus replication required a 40-fold higher drug concentration than did inhibition of virus spread. We also detected variations in the concentrations of drug needed to inhibit virus replication in different cell types. Higher concentrations of drug were needed to inhibit virus replication in chicken embryo fibroblasts than in the continuous quail cell line QT6. Viral DNA synthesis in infected cells was shown to be inhibited in the presence of the drug. The triphosphate form of the analog acted as a competitive inhibitor of purified viral reverse transcriptase, with a Ki of 0.09 +/- 0.003 microM, and was incorporated as a chain terminator during reverse transcription of the natural viral RNA substrate in vitro. Images PMID:2441079

  11. Interaction of 4-azido-2-nitrophenyl phosphate, a pseudosubstrate, with the sarcoplasmic reticulum Ca-ATPase.

    PubMed

    Lacapère, J J; Garin, J

    1994-03-08

    In the dark, 4-azido-2-nitrophenyl phosphate (ANPP) is a phosphate analog which behaves like a simple energy-rich phosphate donor for the sarcoplasmic reticulum (SR) Ca-ATPase. Like p-nitrophenyl phosphate (pNPP), ANPP is hydrolyzed by the enzyme only in the presence of calcium and magnesium (K0.5 and Vmax are 0.3 mM and 60 nmol mg-1 min-1, respectively). After photoirradiation in the absence of magnesium, SR Ca-ATPase is specifically labeled by [32P]ANPP in the presence and in the absence of calcium. The presence of nucleotide in the medium provides some protection against photolabeling but less than phosphorylation by inorganic phosphate. The maximal stoichiometry of covalently bound ANPP extrapolates to 0.8 mol/mol of Ca-ATPase in the absence of magnesium. Autoradiography of a sodium dodecyl sulfate-polyacrylamide gel, after controlled trypsin digestion of the photolabeled protein, reveals that the radioactivity is incorporated in the B subfragment. Three radioactive polypeptides with approximate molecular masses of 55, 25, and 6 kDa are obtained depending on the digestion conditions. N-Terminal sequence analysis of the 50- and 25-kDa peptides reveals the same sequence beginning at Ala-506, whereas two different sequence beginning at Ala-506 and Phe-584 are observed in the 6-kDa peptides.

  12. 5'Azido-N-1-napthylphthalamic acid, a photolabile analog of N-1-naphthylphthalamic acid

    SciTech Connect

    Voet, J.G.; Howley, K.S.; Shumsky, J.S.

    1987-09-01

    A photolabile analog of N-1-naphthylphthalamic acid (NPA), 5'-azido-N-1-naphthylphthalamic acid (Az-NPA), has been synthesized and characterized. This potential photoaffinity label for the plasma membrane NPA binding protein competes with (/sup 3/H)NPA for binding sites on Curcurbita pepo L. (zucchini) hypocotyl cell membranes with K/sub 0.5/ = 2.8 x 10/sup -7/ molar. The K/sub 0.5/ for NPA under these conditions is 2 x 10/sup -8/ molar, indicating that the affinity of Az-NPA for the membranes is only 14-fold lower than NPA. While the binding of Az-NPA to NPA binding sites is reversible in the dark, exposure of the Az-NPA treated membranes to light results in a 30% loss in (/sup 3/H)NPA binding ability. Pretreatment of the membranes with NPA protects the membranes against photodestruction of (/sup 3/H)NPA binding sites by Az-NPA supporting the conclusion that Az-NPA destroys these sites by specific covalent attachment.

  13. Mutagenic nitrenes/nitrenium ions from azido-imidazoarenes and their structure-activity relationships.

    PubMed

    Wild, D; Dirr, A

    1989-11-01

    New heterocyclic arylazides (azido-imidazoarenes) structurally related to the food mutagen/carcinogen 2-amino-3-methyl-imidazo[4,5-f]quinoline (IQ) have been prepared. Their photolysis yields nitrenes and/or nitrenium ions which induce mutations in Salmonella typhimurium. The relationships between the chemical structure and mutagenic activity of these species are the same as those found in our previous studies of the amino- and nitro-imidazoarenes. Therefore the efficiency of the reaction with DNA of the ultimate metabolite, the nitrene/nitrenium ion, is the critical step governing the mutagenic potency of the amino- and nitro-imidazoarenes. The efficiency of DNA-binding depends on the delocalization of the positive charge of the nitrenium ion or of the electron deficiency of the nitrene. It is typical of the N-1-substituted and N-3-substituted arenimidazolyl-nitrenium ions that they can form another nitrenium resonance structure very similar to the parent nitrenium ion structure. We suggest that this property of the nitrene/nitrenium ion, in combination with its aromatic structure facilitating carbonium ion resonance structures, is the basic reason for the extremely potent mutagenic activity of IQ and related food mutagens/carcinogens.

  14. The antiretrovirus drug 3'-azido-3'-deoxythymidine increases the retrovirus mutation rate.

    PubMed Central

    Julias, J G; Kim, T; Arnold, G; Pathak, V K

    1997-01-01

    It was previously observed that the nucleoside analog 5-azacytidine increased the spleen necrosis virus (SNV) mutation rate 13-fold in one cycle of retrovirus replication (V. K. Pathak and H. M. Temin, J. Virol. 66:3093-3100, 1992). Based on this observation, we hypothesized that nucleoside analogs used as antiviral drugs may also increase retrovirus mutation rates. We sought to determine if 3'-azido-3'-deoxythymidine (AZT), the primary treatment for human immunodeficiency virus type 1 (HIV-1) infection, increases the retrovirus mutation rate. Two assays were used to determine the effects of AZT on retrovirus mutation rates. The strategy of the first assay involved measuring the in vivo rate of inactivation of the lacZ gene in one replication cycle of SNV- and murine leukemia virus-based retroviral vectors. We observed 7- and 10-fold increases in the SNV mutant frequency following treatment of target cells with 0.1 and 0.5 microM AZT, respectively. The murine leukemia virus mutant frequency increased two- and threefold following treatment of target cells with 0.5 and 1.0 microM AZT, respectively. The second assay used an SNV-based shuttle vector containing the lacZ alpha gene. Proviruses were recovered as plasmids in Escherichia coli, and the rate of inactivation of lacZ alpha was measured. The results indicated that treatment of target cells increased the overall mutation rate two- to threefold. DNA sequence analysis of mutant proviruses indicated that AZT increased both the deletion and substitution rates. These results suggest that AZT treatment of HIV-1 infection may increase the degree of viral variation and alter virus evolution or pathogenesis. PMID:9151812

  15. Individual susceptibility to DNA telomerase inhibitors: a study on the chromosome instability induced by 3'-azido-3'-deoxythymidine in lymphocytes of elderly twins.

    PubMed

    Caporossi, Daniela; Argentin, Gabriella; Pittaluga, Monica; Parisi, Paolo; Tedeschi, Bruna; Vernole, Patrizia; Cicchetti, Rosadele

    2004-03-01

    The activation of telomerase in phytohemagglutinin-stimulated peripheral lymphocytes is thought to play a role in telomere maintenance and DNA repair. Considering the importance of this enzyme in both cancer and senescence, we studied the effects of the telomerase inhibitor 3'-azido-3'-deoxythymidine on the frequency of chromosomal aberrations and micronuclei induced in peripheral blood lymphocytes (PBL) of elderly monozygotic and dizygotic twins, evaluated with respect to the genotoxic effects induced in unrelated young subjects. Our results show that the cytogenetic damage induced by 3'-azido-3'-deoxythymidine in human PBL was mainly regulated by genetic factors and allowed the identification of hypersensitive subjects. Ageing, which did not modify the individual susceptibility to 3'-azido-3'-deoxythymidine induction of chromosome aberrations and micronuclei, nevertheless determined an overall increase in nuclear damage.

  16. Effects of thymidine and uridine on the phosphorylation of 3'-azido-3'-deoxythymidine (zidovudine) in human mononuclear cells

    SciTech Connect

    Szebeni, J.; Patel, S.S.; Hung, K.; Wahl, L.M.; Weinstein, J.N. )

    1991-01-01

    The effects of thymidine and uridine on the phosphorylation of 3'-azido-3'-deoxythymidine (AZT) were studied in various human mononuclear cell preparations. Thymidine suppressed ({sup 3}H)AZT phosphorylation in the same concentration range (20 to 100 microM) in which it antagonizes the anti-human immunodeficiency virus activity of AZT. Uridine, in turn, had no influence on AZT phosphorylation, just as it has no effect on the anti-human immunodeficiency virus activity of AZT. These findings are consistent with a close relationship between the inhibition of AZT phosphorylation and the influence of physiological nucleosides on the antiviral activity of AZT.

  17. Chemoselective aromatic azido reduction with concomitant aliphatic azide employing Al/Gd triflates/NaI and ESI-MS mechanistic studies.

    PubMed

    Kamal, Ahmed; Markandeya, Nagula; Shankaraiah, Nagula; Reddy, C Ratna; Prabhakar, S; Reddy, C Sanjeeva; Eberlin, Marcos N; Silva Santos, Leonardo

    2009-07-20

    Aluminium and gadolinium triflates catalyze the chemoselective reduction of aromatic azides to the corresponding amines in combination with sodium iodide. This mild chemoselective method has been applied to the synthesis of various aryl amines, C2-azido-substituted pyrrolo[2,1-c][1,4]benzodiazepines, and fused[2,1-b]quinazolinones by an intramolecular azido reduction tandem cyclization reaction. Interestingly, this methodology selectively reduces aryl azides with enhanced yields and proceeds in shorter reaction times than previous strategies. The mechanistic aspects have been investigated and the intermediates associated with this selective transformation have been intercepted and characterized by online monitoring of the reaction by ESI-MS.

  18. Products of the inactivation of ribonucleoside diphosphate reductase from Escherichia coli with 2'-azido-2'-deoxyuridine 5'-diphosphate

    SciTech Connect

    Salowe, S.P.; Ator, M.A.; Stubbe, J.A.

    1987-06-16

    Ribonucleoside diphosphate reductase (RDPR) from Escherichia coli was completely inactivated by 1 equiv of the mechanism-based inhibitor 2'-azido-2'-azido-2'-deoxyuridine 5'-diphosphate (N/sub 3/UDP). Incubation of RDPR with (3'-/sup 3/H)N/sub 3/UDP resulted in 0.2 mol of /sup 3/H released to solvent per mole of enzyme inactivated, indicating that cleavage of the 3' carbon-hydrogen bond occurred in the reaction. Incubation of RDPR with (..beta..-/sup 32/P)N/sub 3/UDP resulted in stoichiometric production of inorganic pyrophosphate. One equivalent of uracil was eliminated from N/sub 3/UDP, but no azide release was detected. Analysis of the reaction of RDPR with (/sup 15/N/sub 3/)N/sub 3/UDP by mass spectrometry revealed that the azide moiety was converted to 0.9 mol of nitrogen gas per mole of enzyme inactivated. The tyrosyl radical of the B2 subunit was destroyed during the inactivation by N/sub 3/UDP as reported previously, while the specific activity of the B1 subunit was reduced by half. Incubation of (5'-/sup 3/H)N/sub 3/UDP with RDPR resulted in stoichiometric covalent radiolabeling of the enzyme. Separation of the enzyme's subunits by chromatofocusing revealed that the modification was specific for the B1 subunit.

  19. Synthesis, characterisation and photochemistry of PtIV pyridyl azido acetato complexes†

    PubMed Central

    Mackay, Fiona S.; Farrer, Nicola J.; Salassa, Luca; Tai, Hui-Chung; Deeth, Robert J.; Moggach, Stephen A.; Wood, Peter A.; Parsons, Simon; Sadler, Peter J.

    2010-01-01

    PtII azido complexes [Pt(bpy)(N3)2] (1), [Pt(phen)(N3)2] (2) and trans-[Pt(N3)2(py)2] (3) incorporating the bidentate diimine ligands 2,2′-bipyridine (bpy), 1,10-phenanthroline (phen) or the monodentate pyridine (py) respectively, have been synthesised from their chlorido precursors and characterised by x-ray crystallography; complex 3 shows significant deviation from square-planar geometry (N3–Pt–N3 angle 146.7°) as a result of steric congestion at the Pt centre. The novel PtIV complexes trans, cis-[Pt(bpy)(OAc)2(N3)2] (4), trans, cis-[Pt(phen)(OAc)2(N3)2] (5), trans, trans, trans-[Pt(OAc)2(N3)2(py)2] (6), were obtained from 1–3 via oxidation with H2O2 in acetic acid followed by reaction of the intermediate with acetic anhydride. Complexes 4–6 exhibit interesting structural and photochemical properties that were studied by x-ray, NMR and UV-vis spectroscopy and TDDFT. These PtIV complexes exhibit greater absorption at longer wavelengths (ε = 9756 M−1cm−1 at 315 nm for 4; ε = 796 M−1cm−1 at 352 nm for 5; ε = 16900 M−1cm−1 at 307 nm for 6, in aqueous solution) than previously reported PtIV azide complexes, due to the presence of aromatic amines, and 4–6 undergo photoactivation with both UVA (365 nm) and visible green light (514 nm). The UV-vis spectra of complexes 4–6 were calculated using TD-DFT; the nature of the transitions contributing to the UV-vis bands provide insight into the mechanism of production of the observed photoproducts. The UV-vis spectra of 1–3 were also simulated by computational methods and comparison between PtII and PtIV electronic and structural properties allowed further elucidation of the photochemistry of 4–6. PMID:19290364

  20. Clickable Cγ-azido(methylene/butylene) peptide nucleic acids and their clicked fluorescent derivatives: synthesis, DNA hybridization properties, and cell penetration studies.

    PubMed

    Jain, Deepak R; Ganesh, Krishna N

    2014-07-18

    Synthesis, characterization, and DNA complementation studies of clickable C(γ)-substituted methylene (azm)/butylene (azb) azido PNAs show that these analogues enhance the stability of the derived PNA:DNA duplexes. The fluorescent PNA oligomers synthesized by their click reaction with propyne carboxyfluorescein are seen to accumulate around the nuclear membrane in 3T3 cells.

  1. A single-chain magnet based on {Co(II)₄} complexes and azido/picolinate ligands.

    PubMed

    Liu, Jiang; Qu, Mei; Rouzières, Mathieu; Zhang, Xian-Ming; Clérac, Rodolphe

    2014-08-04

    A new homonuclear single-chain magnet self-assembles as a one-dimensional coordination network of defective dicubane {Co(II)4} complexes linked by single Co(II) ions with the assistance of azido and picolinate ligands. Dominating intrachain ferromagnetic interactions, intrinsic Ising-like Co(II) anisotropy, and negligible interchain magnetic interactions lead to a thermally activated relaxation time of the magnetization below 8 K. Two thermally activated regimes above and below 3.5 K are observed with the following energy barriers: Δ(τ1)/k(B) = 66 K (τ0 = 3.7 × 10(-11) s) and Δ(τ2)/k(B) = 51 K (τ0 = 2.3 × 10(-9) s), respectively. The difference between the two energy barriers of the relaxation time, 15 K, agrees well with the experimental energy, Δ(ξ), to create a domain wall along the chain.

  2. Novel heterometallic metal-azido complex synthesized by "one-step" reaction: synthetic strategy and magnetic properties

    NASA Astrophysics Data System (ADS)

    Jiao, Yong-Kun; Li, Xiu-Ping; Zhao, Cui; Wang, Hai-Chao; Xue, Min; Zhao, Jiong-Peng; Liu, Fu-Chen

    2013-06-01

    A novel heterometallic complex, [Ni2Mn(N3)2(nic)4·(H2O)2]n (1) (nic=nicotinate), was obtained by assembling MnCl2·4H2O, Ni(NO3)2·6H2O, NaN3 and nicotinic acid with a "one step" synthetic strategy—hydrothermal reaction. The 3D structure of the complex can be described as end-on (EO) azido and syn,syn carboxylates mixed bridged by alternate Ni-Mn-Ni trimers linked by the nicotinate. Dominant ferromagnetic interactions were observed between the NiII and MnII ions in the trimer.

  3. Co(III)(salen)-catalyzed phenolic kinetic resolution of two stereocentered benzyloxy and azido epoxides: its application in the synthesis of ICI-118,551, an anti-hypertensive agent.

    PubMed

    Karabal, Pratibha U; Kamble, Dayanand A; Sudalai, Arumugam

    2014-04-21

    The salen Co(III)-catalyzed phenolic kinetic resolution of racemic anti- or syn-azido and benzyloxy epoxides provides a practical route to a range of enantioenriched anti- or syn-1-aryloxy-3-azido or benzyloxy-2-alcohols in excellent yields and ees. The synthetic potential of this protocol is illustrated with an enantioselective synthesis of ICI-118,551, a β-blocker, in a highly optically pure form (99% ee).

  4. Di-μ-azido-bis­(μ-1,4,7,10,13,16-hexa­oxacyclo­octa­deca­ne)bis­(5,10,15,20-tetra­phenyl­porphyrinato)dicadmium­disodium

    PubMed Central

    Toumi, Hamza; Amiri, Nesrine; Belkhiria, Mohamed Salah; Daran, Jean-Claude; Nasri, Habib

    2012-01-01

    The asymmetric unit of the title compound, [Cd2Na2(N3)2(C44H28N4)2(C12H24O6)2], consists of one half of the dimeric complex; the tetra­nuclear mol­ecule lies about an inversion centre. The CdII atom is coordinated by the four pyrrole N atoms of the 5,10,15,20-tetra­phenyl­porphyrinate ligand and one N atom of the axial azide ligand in a square-pyramidal geometry. The azide group is also linked to the NaI atom, which is surrounded by one 18-crown-6 molecule and additionally bonded to a second 18-crown-6 molecule trans to the azide group. The porphyrin core exhibits a major doming distortion (∼40%) and the crystal structure is stabilized by weak C—H⋯π inter­actions. The mol­ecular structure features weak intra­molecular hydrogen bonds: two O—H⋯O inter­actions within the 18-crown-6 mol­ecule and one C—H(18-crown-6)⋯N(azido) contact. PMID:23468761

  5. Synthesis and characterization of a 1D chain-like Cu{sub 6} substituted sandwich-type phosphotungstate with pendant dinuclear Cu–azido complexes

    SciTech Connect

    Li, Yan-Ying; Zhao, Jun-Wei; Wei, Qi; Yang, Bai-Feng; Yang, Guo-Yu

    2014-02-15

    A novel Cu–azido complex modified hexa-Cu{sup II} substituted sandwich-type phosphotungstate [Cu(en){sub 2}]([Cu{sub 2}(en){sub 2}(μ-1,1-N{sub 3}){sub 2}(H{sub 2}O)]{sub 2}[Cu{sub 6}(en){sub 2}(H{sub 2}O){sub 2}(B-α-PW{sub 9}O{sub 34}){sub 2}])·6H{sub 2}O (1) (en=ethylene-diamine) has been prepared under hydrothermal conditions and structurally characterized by elemental analyses, IR spectra, powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. 1 displays a beautiful 1-D chain architecture constructed from sandwich-type [Cu{sub 2}(en){sub 2}(μ-1,1-N{sub 3}){sub 2}(H{sub 2}O)]{sub 2}[Cu{sub 6}(en){sub 2}(H{sub 2}O){sub 2}(B-α-PW{sub 9}O{sub 34}){sub 2}]{sup 2−} units and [Cu(en){sub 2}]{sup 2+} linkers. To our knowledge, 1 represents the first hexa-Cu{sup II} sandwiched phosphotungstate with supporting Cu–azido complexes. - Graphical abstract: The first hexa-Cu{sup II} sandwiched phosphotungstate with supporting Cu–azido complexes has been prepared and characterized. Display Omitted - Highlights: • Hexa-copper-substituted phosphotungstate. • Cu–azido complexes modified hexa-Cu{sup II} substituted sandwich-type polyoxometalate. • 1-D chain architecture built by hexa-copper-substituted polyoxotungstate units.

  6. A 3D complex containing novel 2D CuII-azido layers: Structure, magnetic properties and effects of “Non-innocent” reagent

    NASA Astrophysics Data System (ADS)

    Gao, Xue-Miao; Guo, Qian; Zhao, Jiong-Peng; Liu, Fu-Chen

    2012-12-01

    A novel copper-azido coordination polymer, [Cu2(N3)3(L)]n (1, HL=pyrazine-2-carboxylic acid), has been synthesized by hydrothermal reaction with “Non-innocent” reagent in the aqueous solution. In the reaction system, CuII ions are avoided to reduce to CuI ions due to the existence of NdIII. It is found that the complex is a 3D structure based on two double EO azido bridged trimmers and octahedron CuII ions, in which the azide ligands take on EO and μ1,1,3 mode to form CuII-azido 2D layers, furthermore L ligands pillar 2D layers into an infinite 3D framework with the Schläfli symbol of {4;62}4{42;612;810;104}{42;64}. Magnetic studies revealed that the interactions between the CuII ions in the trimmer are ferromagnetic for the Cu-N-Cu angle nearly 98°, while the interactions between the trimmer and octahedron CuII ion are antiferromgantic and result in an antiferromagnetic state.

  7. A 3D complex containing novel 2D Cu{sup II}-azido layers: Structure, magnetic properties and effects of 'Non-innocent' reagent

    SciTech Connect

    Gao, Xue-Miao; Guo, Qian; Zhao, Jiong-Peng; Liu, Fu-Chen

    2012-12-15

    A novel copper-azido coordination polymer, [Cu{sub 2}(N{sub 3}){sub 3}(L)]{sub n} (1, HL=pyrazine-2-carboxylic acid), has been synthesized by hydrothermal reaction with 'Non-innocent' reagent in the aqueous solution. In the reaction system, Cu{sup II} ions are avoided to reduce to Cu{sup I} ions due to the existence of Nd{sup III}. It is found that the complex is a 3D structure based on two double EO azido bridged trimmers and octahedron Cu{sup II} ions, in which the azide ligands take on EO and {mu}{sub 1,1,3} mode to form Cu{sup II}-azido 2D layers, furthermore L ligands pillar 2D layers into an infinite 3D framework with the Schlaefli symbol of {l_brace}4;6{sup 2}{r_brace}4{l_brace}4{sup 2};6{sup 12};8{sup 10};10{sup 4}{r_brace}{l_brace}4{sup 2};6{sup 4}{r_brace}. Magnetic studies revealed that the interactions between the Cu{sup II} ions in the trimmer are ferromagnetic for the Cu-N-Cu angle nearly 98 Degree-Sign , while the interactions between the trimmer and octahedron Cu{sup II} ion are antiferromgantic and result in an antiferromagnetic state. - Graphical abstract: A 3D complex containing novel 2D Cu{sup II}-azido layers, [Cu{sub 2}(N{sub 3}){sub 3}(L)]{sub n} (HL=pyrazine-2-carboxylic acid), was synthesized by hydrothermal reaction and exhibit interesting structure and magnetic properties. Highlights: Black-Right-Pointing-Pointer 'Non-innocent' reagents plays a key role in the process of formation of this complex. Black-Right-Pointing-Pointer 2D layer is formed only by Cu{sup II} ions and azido ligands. Black-Right-Pointing-Pointer Pyrazine-2-carboxylate ligands reinforce 2D layers and pillar them into an infinite 3D framework. Black-Right-Pointing-Pointer Magnetic study indicates that alternating FM-AF coupling exists in the complex.

  8. Facile entry into triazole fused heterocycles via sulfamidate derived azido-alkynes.

    PubMed

    Sai Sudhir, V; Phani Kumar, N Y; Nasir Baig, R B; Chandrasekaran, Srinivasan

    2009-10-02

    Direct synthesis of condensed triazoles from diverse sulfamidates by ring opening of sulfamidates with sodium azide followed by one-pot propargylation and cycloaddition furnished title compounds. The methodology in general has been demonstrated on diverse sulfamidates derived from amino acids, amino acid derivatives, and carbohydrates to obtain diverse triazole fused scaffolds. In one example, a condensed triazole containing amino acid has been synthesized by ring opening of a sulfamidate derivative with propargyl amine.

  9. Micelle-Enhanced Bioorthogonal Labeling of Genetically Encoded Azido Groups on the Lipid-Embedded Surface of a GPCR.

    PubMed

    Tian, He; Sakmar, Thomas P; Huber, Thomas

    2015-06-15

    Genetically encoded p-azido-phenylalanine (azF) residues in G protein-coupled receptors (GPCRs) can be targeted with dibenzocyclooctyne-modified (DIBO-modified) fluorescent probes by means of strain-promoted [3+2] azide-alkyne cycloaddition (SpAAC). Here we show that azF residues situated on the transmembrane surfaces of detergent-solubilized receptors exhibit up to 1000-fold rate enhancement relative to azF residues on water-exposed surfaces. We show that the amphipathic moment of the labeling reagent, consisting of hydrophobic DIBO coupled to hydrophilic Alexa dye, results in strong partitioning of the DIBO group into the hydrocarbon core of the detergent micelle and consequently high local reactant concentrations. The observed rate constant for the micelleenhanced SpAAC is comparable with those of the fastest bioorthogonal labeling reactions known. Targeting hydrophobic regions of membrane proteins by use of micelle-enhanced SpAAC should expand the utility of bioorthogonal labeling strategies.

  10. Site-specific labeling of genetically encoded azido groups for multicolor, single-molecule fluorescence imaging of GPCRs.

    PubMed

    Tian, He; Sakmar, Thomas P; Huber, Thomas

    2013-01-01

    Heptahelical G protein-coupled receptors (GPCRs) mediate transmembrane signal transduction to facilitate intercellular communication. GPCRs assemble in the membrane bilayer with a variety of cytoplasmic adapter and scaffold proteins to form molecular machines, or "signalosomes," which undergo complex dynamic assembly and disassembly reactions. Despite significant recent advances in structural studies of GPCRs and their associated cytoplasmic components, understanding transmembrane signaling in four dimensions with chemical precision requires new approaches. One promising approach to study allosteric effects involved in signalosome reaction pathways is to use multicolor single-molecule detection (SMD) fluorescence experiments in biochemically defined systems. We describe here the methodological foundation for automated, multicolor, single-molecule fluorescence studies of the structural and compositional dynamics of macromolecular complexes involved in signal transduction. We present a general, simple, and robust method for stoichiometric, site-specific fluorescence labeling of expressed GPCRs. The method is based on bioorthogonal conjugation of a fluorescent reporter group to a genetically encoded azido group introduced into expressed GPCRs using amber codon suppression. We then present a strategy to reconstitute labeled GPCRs in native-like membranes and to tether-oriented samples onto surfaces amenable for interrogation by total internal reflectance fluorescence (TIRF) spectroscopy. We describe how to assemble an automated four-color epifluorescence microscope with SMD-TIRF optics. Finally, we discuss how to adapt engineered samples for high-throughput imaging with the aim of understanding the kinetic relationships between ligand binding and the dynamic regulation of the GPCR signalosome.

  11. Multi-Fluorinated Azido Coumarins for Rapid and Selective Detection of Biological H2 S in Living Cells.

    PubMed

    Zhu, Zhentao; Li, Yanyan; Wei, Chao; Wen, Xin; Xi, Zhen; Yi, Long

    2016-01-01

    Hydrogen sulfide (H2 S) is an endogenously produced gaseous signaling molecule with multiple biological functions. In order to visualize the endogenous in situ production of H2 S in living cells in real time, here we developed multi-fluorinated azido coumarins as fluorescent probes for the rapid and selective detection of biological H2 S. Kinetic studies indicated that an increase in fluorine substitution leads to an increased rate of H2 S-mediated reduction reaction, which is also supported by our theoretical calculations. To our delight, tetra-fluorinated coumarin 1 could react with H2 S fast (t1/2 ≈1 min) and selectively, which could be further used for continuous enzymatic assays and for visualization of intracellular H2 S. Bioimaging results obtained with 1 revealed that d-Cys could induce a higher level of endogenous H2 S production than l-Cys in a time-dependent manner in living cell.

  12. Azido and tetrazolo 1,2,4,5-tetrazine N-oxides

    DOE PAGES

    Chavez, David E.; Parrish, Damon A.; Mitchell, Lauren; ...

    2017-02-23

    This paper presents the synthesis and characterization of the oxidation products of 3,6-diazido-1,2,4,5-tetrazine (1) and 6-amino-[1,5-b]tetrazolo-1,2,4,5-tetrazine (2). 3,6-Diazido-1,2,4,5-tetrazine-1,4-dioxide was produced from oxidation with peroxytrifluoroacetic acid, and more effectively using hypofluorous acid, and 2 can be oxidized to two different products, 6-amino-[1,5-b]tetrazolo-1,2,4,5-tetrazine mono-N-oxide and di-N-oxide. These N-oxide compounds display promising performance properties as energetic materials.

  13. Crystal structures of μ-oxalato-bis­[azido­(hista­mine)­copper(II)] and μ-oxalato-bis­[(dicyan­amido)(hista­mine)­copper(II)

    PubMed Central

    Liu, Chen; Abboud, Khalil A.

    2015-01-01

    The title compounds, μ-oxalato-κ4 O 1,O 2:O 1′,O 2′-bis­[[4-(2-amino­eth­yl)-1H-imid­azole-κ2 N 3,N 4](azido-κN 1)copper(II)], [Cu2(C2O4)(N3)2(C5H9N3)2], (I), and μ-ox­al­ato-κ4 O 1,O 2:O 1′,O 2′-bis­[[4-(2-amino­eth­yl)-1H-imidazole-κ2 N 3,N 4](dicyanamido-κN 1)copper(II)], [Cu2(C2O4)(C2N3)2(C5H9N3)2], (II), are two oxalate-bridged dinuclear copper complexes. Each CuII ion adopts a five-coordinate square-pyramidal coordination sphere where the basal N2O2 plane is formed by two O atoms of the oxalate ligand and two N atoms of a bidentate chelating histamine mol­ecule. The apical coordination site in compound (I) is occupied by a monodentate azide anion through one of its terminal N atoms. The apical coordination site in compound (II) is occupied by a monodentate dicyanamide anion through one of its terminal N atoms. The mol­ecules in both structures are centrosymmetric. In the crystals of compounds (I) and (II), the dinuclear complexes are linked through N—H⋯X and C—H⋯X (X = N, O) hydrogen bonds where the donors are provided by the histamine ligand and the acceptor atoms are provided by the azide, dicyanamide, and oxalate ligands. In compound (I), the coordinatively unsaturated copper ions inter­act with the histamine ligand via a C—H⋯Cu inter­action. The coordinatively unsaturated copper ions in compound (II) inter­act via a weak N⋯Cu inter­action with the dicyanamide ligand of a neighboring mol­ecule. The side chain of the histamine ligand is disordered over three sets of sites in (II). PMID:26594515

  14. The First-Principle Study on the Crystal Structures of Azido Derivatives of Benzene

    NASA Astrophysics Data System (ADS)

    Du, Hong-Chen; Wang, Yu

    2014-07-01

    A molecular mechanics method with COMPASS and Dreiding force fields was used to predict molecular packings for the three title compounds among seven possible space groups (P21/c, P212121, P-1, Pbca, C2/c, Pna21, and P21). Then, periodic band calculations were performed on the predicted crystals using the density functional theory generalized gradient approximation with revised Perdew-Burke-Ernzerhof (DFT-GGA-RPBE) functional method. The obtained density of state (DOS) showed that the C-N3 bonds are possibly the trigger bond during thermolysis. The band gaps (ΔEg) were slightly different and hexaazidobenzene was more sensitive than the two others. Periodic calculation results on DOS were consistent with those obtained from bond dissociation energy calculations on gas molecules.

  15. Evidence of robust participation by an equatorial 4-O group in glycosylation on a 2-azido-2-deoxy-glucopyranosyl donor.

    PubMed

    Yao, Dongming; Liu, Yichu; Yan, Shiqiang; Li, Yingxia; Hu, Chun; Ding, Ning

    2017-03-07

    Although there are numerous claims of remote group participation leading to the synthesis of the expected glycosides with improved anomeric geometry outcome in glycosylation, there is still a lack of enough strong evidence and this has led to a long-term debate, particularly for equatorial 4-O group participation. In this work, we were able to synthesize and isolate a stable seven-membered trichlorooxazepine ring bridging intermediate with a high yield by employing a 2-azido-2-deoxy-glucopyranosyl donor, which provides strong evidence to support the putative participation of the equatorial 4-O group in glycosylation.

  16. In situ tetrazole templated chair-like decanuclear azido-cobalt(II) SMM containing both tetra- and octa-hedral Co(II) ions.

    PubMed

    Zhang, Yuan-Zhu; Gao, Song; Sato, Osamu

    2015-01-14

    An azido-bridged chair-like decanuclear cluster: [Co(II)10(bzp)8(Metz)2(N3)18]·4MeOH·3H2O (1, bzp = 2-benzoylpyridine and HMetz = 5-methyl-1H-tetrazole) was prepared with in situ tetrazolate anions as templates in a sealed system. 1 containing both octahedral and tetrahedral Co(II) ions exhibited slow relaxation of magnetization with an effective barrier of 26 K under an applied dc field of 1 kOe.

  17. Syntheses of the Stemona Alkaloids (±)-Stenine, (±)-Neostenine, and (±)-13-Epineostenine Using a Stereodivergent Diels-Alder/Azido-Schmidt Reaction

    PubMed Central

    Frankowski, Kevin J.; Golden, Jennifer E.; Zeng, Yibin; Lei, Yao; Aubé, Jeffrey

    2009-01-01

    A tandem Diels-Alder/azido Schmidt reaction sequence provides rapid access to the core skeleton shared by several Stemona alkaloids including stenine, neostenine, tuberstemonine, and neotubererostemonine. The discovery and evolution of inter- and intramolecular variations of this process and their applications to total syntheses of (±)–stenine and (±)–neostenine is described. The stereochemical outcome of the reaction depends on both substrate type and reaction condition, enabling the preparation of both (±)–stenine and (±)–neostenine from the same diene/dienophile combination. PMID:18396881

  18. Simple and high yield access to octafunctional azido, amine and urea group bearing cubic spherosilicates.

    PubMed

    Schäfer, Sandra; Kickelbick, Guido

    2016-12-20

    Spherosilicates and polyhedral oligomeric silsesquioxanes represent unique well-defined rigid building blocks for molecular and hybrid materials. Drawbacks in their synthesis are often low yields and the restricted presence of functional groups either based on incomplete transformation of all corners or the reactivity of the functional groups. Particularly amine-functionalization reveals some synthetic challenges. In this study we report the synthesis of a new class of octafunctionalized hydrogen bond forming spherosilicates via a facile route based on octabromo alkyl functionalized cubic spherosilicates. Four different alkyl chain lengths, namely C4, C5, C6 and C11, were realized starting from ω-alkenylbromides via hydrosilylation of Q8M8(H). Using sodium azide in a mixture of acetonitrile : DMF = 10 : 1, the octaazide was obtained quantitatively and could be rapidly transformed in an octaamine cube via catalytic hydrogenation over Pd/C in absolute ethanol. The following reaction to hydrogen bond forming spherosilicates was performed in situ by adding propyl isocyanate. All transformations proceed quantitatively at the eight corners of the cube, which was evidenced by NMR spectroscopy and ESI-MS measurements. The Q8-target compound can be separated after each reaction step over simple chemical workup while no cage rearrangement was observed. The structures were confirmed using (1)H, (13)C, (29)Si-NMR, FT-IR, elemental analysis and ESI-MS. The method opens a high yield route (overall isolated yield 83-88%) for structural building blocks in hybrid materials.

  19. Copper(II) coordination chain complex with the 2,5-bis(2-pyridyl)-1,3,4-thiadiazole ligand and an asymmetric μ2-1,1-azido double-bridged: Synthesis, crystal structure and magnetic properties

    NASA Astrophysics Data System (ADS)

    Laachir, Abdelhakim; Guesmi, Salaheddine; Saadi, Mohamed; El Ammari, Lahcen; Mentré, Olivier; Vezin, Hervé; Colis, Silviu; Bentiss, Fouad

    2016-11-01

    A new asymmetric μ2-1,1-azido double bridged cooper (II), with 2,5-bis(2-pyridyl)-1,3,4-thiadiazole (L), has been synthesized and characterized using single crystal X-ray diffraction, FT-IR, UV-Visible spectroscopic and magnetic measurements. The asymmetric unit of the title compound contains half molecule of formula, C12H8CuN10S, which crystallizes in the triclinic system, space group P 1 bar , with a = 6.5916 (4)Å, b = 10.6905 (7) Å, c = 11.5037 (7) Å, α = 106.508 (3)°, β = 105.538 (3)°, γ = 90.233 (4)°, V = 745.99 (8) Å3 and Z = 2. The structure consists of two [CuN5] prismatic polyhedra linked together by edge-sharing to build up a [Cu2N8] dimer arranged in chain. The connectivity along the chain is performed by Nsbnd N edge sharing between dimers. In the crystal, the molecules are linked together by Csbnd H⋯N hydrogen bonds and by π---π interactions between parallel pyridyl rings of neighboring molecules. The interpretation of FT-IR and UV-Vis spectra is consistent with the crystal structure determined by X-ray diffraction. The magnetic properties of the complex confirm the picture of an alternated … Cu-J1-Cu ….J2 … Cu-J1-Cu … magnetic chains. We found in the dimers weak antiferromagnetic exchange interactions J1/k = -5.9 (1) k and between them J2/k = -2.3 k.

  20. Photoaffinity labeling of the rat plasma vitamin D binding protein with (26,27-3H)-25-hydroxyvitamin D3 3 beta-(N-(4-azido-2-nitrophenyl)glycinate)

    SciTech Connect

    Ray, R.; Holick, S.A.; Hanafin, N.; Holick, M.F.

    1986-08-26

    It is well recognized that the vitamin D binding protein (DBP) is important for the transport of vitamin D, 25-hydroxyvitamin D (25-OH-D), and its metabolites. In an attempt to better understand the molecular-binding properties of this ubiquitous protein, we designed and synthesized a photoaffinity analogue of 25-OH-D3 and its radiolabeled counterpart. This analogue, 25-hydroxyvitamin D3 3 beta-(N-(4-azido-2-nitrophenyl)glycinate) (25-OH-D3-ANG), was recognized by the rat DBP and was about 10 times less active than 25-OH-D3 in terms of binding. Incubation of (/sup 3/H)25-OH-D3 or (/sup 3/H)25-OH-D3-ANG with rat DBP revealed that both compounds were specifically bound to a protein with a sedimentation coefficient of 4.1 S. Each was displaced with a 500-fold excess of 25-OH-D3. When (/sup 3/H)25-OH-D3-ANG was exposed to UV radiation in the presence of rat DBP followed by the addition of a 500-fold excess of 25-OH-D3, there was no displacement of tritium from the 4.1S peak. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis autoradiographic analysis of (/sup 3/H)25-OH-D3-ANG exposed to UV radiation in the presence of rat DBP followed by the addition of a 500-fold excess of 25-OH-D3 revealed one major band with a molecular weight of 52 000. These data provide strong evidence that (/sup 3/H)25-OH-D3-ANG was covalently linked to the rat DBP. This photoaffinity probe should provide a valuable tool for the analysis of the binding site on this transport protein.

  1. Azido- and chlorido-cobalt complex as carrier-prototypes for antitumoral prodrugs.

    PubMed

    Pires, Bianca M; Giacomin, Letícia C; Castro, Frederico A V; Cavalcanti, Amanda dos S; Pereira, Marcos D; Bortoluzzi, Adailton J; Faria, Roberto B; Scarpellini, Marciela

    2016-04-01

    Cobalt(III) complexes are well-suited systems for cytotoxic drug release under hypoxic conditions. Here, we investigate the effect of cytotoxic azide release by cobalt-containing carrier-prototypes for antitumoral prodrugs. In addition, we study the species formed after reduction of Co(3+) → Co(2+) in the proposed models for these prodrugs. Three new complexes, [Co(III)(L)(N3)2]BF4(1), [{Co(II)(L)(N3)}2](ClO4)2(2), and [Co(II)(L)Cl]PF6(3), L=[(bis(1-methylimidazol-2-yl)methyl)(2-(pyridyl-2-yl)ethyl)amine], were synthesized and studied by several spectroscopic, spectrometric, electrochemical, and crystallographic methods. Reactivity and spectroscopic data reveal that complex 1 is able to release N3(-) either after reduction with ascorbic acid, or by ambient light irradiation, in aqueous phosphate buffer (pH6.2, 7.0 and 7.4) and acetonitrile solutions. The antitumoral activities of compounds 1-3 were tested in normoxia on MCF-7 (human breast adenocarcinoma), PC-3 (human prostate) and A-549 (human lung adenocarcinoma epithelial) cell lines, after 24h of exposure. Either complexes or NaN3 presented IC50 values higher than 200 μM, showing lower cytotoxicity than the clinical standard antitumoral complex cisplatin, under the same conditions. Complexes 1-3 were also evaluated in hypoxia on A-549 and results indicate high IC50 data (>200 μM) after 24h of exposure. However, an increase of cancer cell susceptibility to 1 and 2 was observed at 300 μM. Regarding complex 3, no cytotoxic activity was observed in the same conditions. The data presented here indicate that the tridentate ligand L is able to stabilize both oxidation states of cobalt (+3 and +2). In addition, the cobalt(III) complex generates the low cytotoxic cobalt(II) species after reduction, which supports their use as as carrier prototypes for antitumoral prodrugs. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Rapid grafting of azido-labeled oligo(ethylene glycol)s onto an alkynyl-terminated monolayer on nonoxidized silicon via microwave-assisted "click" reaction.

    PubMed

    Li, Yan; Wang, Jun; Cai, Chengzhi

    2011-03-15

    Microwave (MW) irradiation was used for the grafting of azido-labeled oligo(ethylene oxide) (OEG) on alkynyl-terminated nonoxidized silicon substrates via copper-catalyzed "click" reaction. The "clickable" monolayers were prepared by photografting of an α,ω-alkynene, where the alkynyl terminus was protected by a trimethylgermanyl (TMG) group, onto hydrogen-terminated Si(111) surfaces. X-ray photoelectron spectroscopy (XPS) was primarily employed to characterize the monolayers, and the data obtained were utilized to calculate the surface density of the TMG-alkynyl-functionalized substrate. MW-assisted one-pot deprotection/click reaction was optimized on the surfaces using azido-tagged OEG derivatives. Using MW instead of conventional heating led to a substantial improvement in the rate of the reaction while suppressing the oxidation of the silicon interface and OEG degradation. The antifouling property of the resulting substrates was evaluated using fibrinogen as a model protein. Results show that the OEG-modification reduced the protein adsorption by >90%.

  3. Doubly end-on azido bridged mixed-valence cobalt trinuclear complex: Spectral study, VTM, inhibitory effect and antimycobacterial activity on human carcinoma and tuberculosis cells

    NASA Astrophysics Data System (ADS)

    Datta, Amitabha; Das, Kuheli; Sen, Chandana; Karan, Nirmal Kumar; Huang, Jui-Hsien; Lin, Chia-Her; Garribba, Eugenio; Sinha, Chittaranjan; Askun, Tulin; Celikboyun, Pinar; Mane, Sandeep B.

    2015-09-01

    Doubly end-on azido-bridged mixed-valence trinuclear cobalt complex, [Co3(L)2(N3)6(CH3OH)2] (1) is afforded by employing a potential monoanionic tetradentate-N2O2 Schiff base precursor (2-[{[2-(dimethylamino)ethyl]imino}methyl]-6-methoxyphenol; HL). Single crystal X-ray structure reveals that in 1, the adjacent CoII and CoIII ions are linked by double end-on azido bridges and thus the full molecule is generated by the site symmetry of a crystallographic twofold rotation axis. Complex 1 is subjected on different spectral analysis such as IR, UV-vis, emission and EPR spectroscopy. On variable temperature magnetic study, we observe that during cooling, the χMT values decrease smoothly until 15 K and then reaches to the value 1.56 cm3 K mol-1 at 2 K. Complex 1 inhibits the cell growth on human lung carcinoma (A549 cells), human colorectal (COLO 205 and HT-29 cells), and human heptacellular (PLC5 cells) carcinoma cells. Complex 1 exhibits anti-mycobacterial activity and considerable efficacy on Mycobacterium tuberculosis H37Rv ATCC 27294 and H37Ra ATCC 25177 strains.

  4. Synthesis and characterization of ( sup 3 H)-5 prime azido-N-1-naphthylphthlamic acid, a photolabile N-1-naphthylphthalamic acid analog

    SciTech Connect

    Voet, J.G.; Dodge, B.; Harris, K.; Jacobs, M.; Larkin, L.; Bader, S.; Schnitzler, G.; Sutherland, J. )

    1990-05-01

    The NPA (N-1-naphthylphthalamic acid) receptor is an important protein involved in the regulation of transport of indole-3-acetic acid (IAA). In our attempt to isolate and characterize this protein we have previously synthesized and characterized a photolabile analog of NPA, 5{prime}-azido-NPA (Az-NPA) and shown it to be a competitor of NPA for binding sites on the NPA receptor as well as an inhibitor of auxin transport. We have now synthesized and characterized ({sup 3}H)-Az-NPA. The precursor, 2,3,4,5-Br-5{prime}-amino-NPA was dehydrohalogenated with tritium gas by Research Products International. The amino group was converted to an azido group and the product purified by HPLC. ({sup 3}H)-Az-NPA was found to be photolabile and to co-chromatograph with our synthetic unlabeled Az-NPA. Furthermore, the tritiated material was found to bind to zucchini hypocotyl cell membranes in a manner competitive with NPA as well as unlabeled Az-NPA. Photolysis of zucchini phase-partitioned plasma membranes in the presence of ({sup 3}H)-Az-NPA resulted in covalent association of tritium with the membranes. Much of this covalent association could be prevented by prior treatment of the membranes with excess NPA.

  5. Three-dimensional structure of thymidine phosphorylase from E. coli in complex with 3'-azido-2'-fluoro-2',3'-dideoxyuridine

    NASA Astrophysics Data System (ADS)

    Timofeev, V. I.; Abramchik, Yu. A.; Fateev, I. V.; Zhukhlistova, N. E.; Murav'eva, T. I.; Kuranova, I. P.; Esipov, R. S.

    2013-11-01

    The three-dimensional structures of thymidine phosphorylase from E. coli containing the bound sulfate ion in the phosphate-binding site and of the complex of thymidine phosphorylase with sulfate in the phosphate-binding site and the inhibitor 3'-azido-2'-fluoro-2',3'-dideoxyuridine (N3F-ddU) in the nucleoside-binding site were determined at 1.55 and 1.50 Å resolution, respectively. The amino-acid residues involved in the ligand binding and the hydrogen-bond network in the active site occupied by a large number of bound water molecules are described. A comparison of the structure of thymidine phosphorylase in complex with N3F-ddU with the structure of pyrimidine nucleoside phosphorylase from St. Aureus in complex with the natural substrate thymidine (PDB_ID: 3H5Q) shows that the substrate and the inhibitor in the nucleoside-binding pocket have different orientations. It is suggested that the position of N3F-ddU can be influenced by the presence of the azido group, which prefers a hydrophobic environment. In both structures, the active sites of the subunits are in the open conformation.

  6. Mononuclear thiocyanate containing nickel(II) and binuclear azido bridged nickel(II) complexes of N4-coordinate pyrazole based ligand: Syntheses, structures and magnetic properties

    NASA Astrophysics Data System (ADS)

    Solanki, Ankita; Monfort, Montserrat; Kumar, Sujit Baran

    2013-10-01

    Two mononuclear nickel(II) complexes [NiL1(NCS)2] (1) and [NiL2(NCS)2] (2) and two azido bridged binuclear nickel(II) complexes [Ni(()2()2] (3) and [Ni(()2()2] (4), where L1, L2, L1‧ and L2‧ are N,N-diethyl-N‧,N‧-bis((3,5-dimethyl-1H-pyrazol-1-yl)methyl)ethane-1,2-diamine (L1), N,N-bis((1H-pyrazol-1-yl)methyl)-N‧,N‧-diethylethane-1,2-diamine (L2), N,N-diethyl-N‧-((3,5-dimethyl-1H-pyrazol-1-yl)methyl)ethane-1,2-diamine (L1‧) and N-((1H-pyrazol-1-yl)methyl)-N‧,N‧-diethylethane-1,2-diamine (L2‧) have been synthesized and characterized by microanalyses and physico-chemical methods. Single crystal X-ray diffraction analyses revealed that complexes 1 and 2 are mononuclear NCS- containing Ni(II) complex with octahedral geometry and complexes 3 and 4 are end-on (μ-1,1) azido bridged binuclear Ni(II) complexes with distorted octahedral geometry. Variable temperature magnetic studies of the complexes 3 and 4 display ferromagnetic interaction with J values 19 and 32 cm-1, respectively.

  7. The azide-bridged mixed-valent cobalt(II,III) compound [(CH(3))(3)NH](2)[CoCo(2)(N(3))(10)].

    PubMed

    Liu, Yan-Ju; Li, Yu-Xian; Xu, Min; Wang, Xia

    2010-12-04

    The crystal structure of the title compound, poly[bis-(tri-methyl-ammonium) hexa-μ(1,1)-azido-tetra-azido-tricobalt-ate(II,III)], [(CH(3))(3)NH](2)[Co(II)Co(III) (2)(N(3))(10)], consists of anionic chains [Co(II)Co(III) (2)(N(3))(10)](2-) extending parallel to the c axis and [(CH(3))(3)NH](+) counter-cations situated between the chains. In the anionic chain, one tetra-hedrally coordinated Co(II) atom (site symmetry 2) and two octa-hedrally coordinated Co(III) atoms are arranged alternately and are linked by μ(1,1)-azide bridges. The anionic chains and cations are connected via N-H⋯N hydrogen bonding into a three-dimensional structure.

  8. AIMS simulation study of ultrafast electronically nonadiabatic chemistry of methyl azide and UV-VIS spectroscopic study of azido-based energetic plasticizer bis(1,3-diazido prop-2-yl)malonate

    NASA Astrophysics Data System (ADS)

    Ghosh, Jayanta; Banerjee, Shaibal; Bhattacharya, Atanu

    2017-09-01

    To gain insight into the ultrafast electronically nonadiabatic chemistry of azido-based energetic plasticizer, we have explored the nonadiabatic chemical dynamics of an azido-based model analog molecule, methyl azide (MAz), using ab initio multiple spawning (AIMS) simulation and electronic structure theory calculations. Molecular nitrogen (N2) is predicted to be the initial product of MAz following its electronic excitation to the S1 electronically excited state. AIMS-based simulation reveals that electronically excited azido-based molecules undergo extremely fast (approximately in 40 femtoseconds) relaxation to the ground state via the (S1/S0)CI conical intersection. Furthermore, this relaxation process involves the Nsbnd N bond elongation along with the bending of N3 moiety. This is the first report on the electronically non-adiabatic chemical dynamics (in ultrafast time domain) of methyl azide. Finally, using ultraviolet-visible (UV-VIS) spectroscopy, we comment on the electronically nonadiabatic chemistry of azido-based energetic plasticizer, bis(1,3-diazido prop-2-yl)malonate.

  9. Identification of UDPG-binding polypeptides and purified (1,3)-. beta. -glucan synthase by photoaffinity labelling with 5-azido-UDPG

    SciTech Connect

    Frost, D.J.; Wu, A.; Read, S.M.; Wasserman, B.P. ); Drake, R.R.; Haley, B.E. )

    1989-04-01

    The photoaffinity probe 5-azido-uridine 5{prime}-{beta}-({sup 32}P)-diphosphate glucose was used to identify the major UDPG-binding polypeptide of red beet (1,3)-{beta}-glucan synthase. Glucan synthase was purified from plasma membranes by sequential solubilization with CHAPS followed by product entrapment. Two major polypeptides at 72 and 54 kD were labelled by probe. Labelling of both was abolished with increasing levels of cold UDPG. However, labelling of the 54 kD polypeptide was dependent upon the presence of divalent cations. These data suggest that the 54 kD polypeptide is a substrate-binding and cation-regulated component of the glucan synthase complex.

  10. SYNTHESIS, CHARACTERIZATION, AND IN VITRO ASSAY OF FOLIC ACID CONJUGATES OF 3′-AZIDO-3′-DEOXYTHYMIDINE (AZT): TOWARD TARGETED AZT BASED ANTICANCER THERAPEUTICS

    PubMed Central

    Vortherms, Anthony R.; Doyle, Robert P.; Gao, Dayuan; Debrah, Olivia; Sinko, Patrick J.

    2009-01-01

    Conjugates of three components namely folic acid, poly(ethylene glycol) and 3′-azido-3′-deoxythymidine (AZT) are presented. Folate-PEG units were coupled to AZT to facilitate delivery of the nucleoside into the cell. A convenient separation of the polydisperse PEGylated-folic acid regioisomers produced upon conjugation is described. This is to select for the active γ-regioisomer over the inactive α-regioisomer. In vitro cytotoxicity assays were conducted against an ovarian cell line (A2780/AD) that overexpresses the folate receptor (FR) and compared to a FR free control cell line. Compared to AZT a ~ 20-fold greater potency against the resistant ovarian line was observed for the conjugates. PMID:18205071

  11. Large scale synthesis and regioselective protection schemes of ethyl 2-azido-2-deoxy-1-thio-α-d-cellobioside for preparation of heparin thiodisaccharide building blocks.

    PubMed

    Sheerin, Kevin; Guazzelli, Lorenzo; Oscarson, Stefan

    2017-02-22

    Crystalline acetylated ethyl 2-azido-2-deoxy-1-thio-α-d-cellobioside has been prepared on a multigram scale from cellobiose in an overall yield of 23% with no chromatography required and converted after deacetylation into the 4',6'-O-benzylidene and 4',6'-O-benzylidene-6-O-TBDMS protected derivatives. Applying a number of regioselective benzylation methods on these gave access to a variety of regioselectively protected derivatives, both mono-ols (2'- and 3-OH), diols (2',6-, 2',3-, and 3,6-di-OH), and triols (2',3,6- and 2',3',3-tri-OH). A number of these derivatives were further processed by benzoylation followed by removal or opening of the benzylidene acetal and selective oxidation of the exposed primary alcohol to give heparin building block intermediates comprising a range of possible sulfation patterns.

  12. Reversal of brain metabolic abnormalities following treatment of AIDS dementia complex with 3'-azido-2',3'-dideoxythymidine (AZT, zidovudine): a PET-FDG study

    SciTech Connect

    Brunetti, A.; Berg, G.; Di Chiro, G.; Cohen, R.M.; Yarchoan, R.; Pizzo, P.A.; Broder, S.; Eddy, J.; Fulham, M.J.; Finn, R.D.

    1989-05-01

    Brain glucose metabolism was evaluated in four patients with acquired immunodeficiency syndrome (AIDS) dementia complex using (/sup 18/F)fluorodeoxyglucose (FDG) and positron emission tomography (PET) scans at the beginning of therapy with 3'-azido-2',3'-dideoxythymidine (AZT, zidovudine), and later in the course of therapy. In two patients, baseline, large focal cortical abnormalities of glucose utilization were reversed during the course of therapy. In the other two patients, the initial PET study did not reveal pronounced focal alterations, while the post-treatment scans showed markedly increased cortical glucose metabolism. The improved cortical glucose utilization was accompanied in all patients by immunologic and neurologic improvement. PET-FDG studies can detect cortical metabolic abnormalities associated with AIDS dementia complex, and may be used to monitor the metabolic improvement in response to AZT treatment.

  13. Density functional theory study of high-pressure effect on crystalline 4,4',6,6'-tetra(azido)hydrazo-1,3,5-triazine.

    PubMed

    Wang, Fang; Du, Hong-Chen; Liu, Hui; Gong, Xue-Dong

    2012-08-15

    Periodic density functional theory calculations are performed to study the hydrostatic compression effects on the structure, electronic, and thermodynamic properties of the energetic polyazide 4,4',6,6'-tetra(azido)hydrazo-1,3,5-triazine (TAHT) in the range of 0-100 GPa. At the ambient pressure, the local density approximation/Ceperley-Alder exchange-correlation potential parameterized by Perdew and Zunger relaxed crystal structure compares well with the experimental results. The predicted heat of sublimation is 38.68 kcal/mol, and the evaluated condensed phase of formation (414.04 kcal/mol) approximates to the experimental value. The detonation velocity and detonation pressure for the solid TAHT are calculated to be 7.44 km/s and 23.71 GPa, respectively. When the pressure is exerted less than 35 GPa, the crystal structure and geometric parameters change slightly. However, at 36 GPa, the molecular structure, band structure, and density of states change abnormally because of the azide-tetrazole transformation that has not been observed in gas phase or polar solvents. The azido group cyclizes to form a five-membered tetrazole ring that is coplanar with the riazine ring and contributes to a larger conjunction system. As the pressure augments further to 80 GPa, the hydrogen transfer is found and a new covalent bond H2-N9 is formed. In the studied pressure range, the band gap decreases generally except for some breaks due to the molecular transformation and drops to nearly zero at 100 GPa, which means the electronic character of the crystal changes toward a metallic system. An analysis of the electronic structure shows that an applied pressure increases the impact sensitivity of TAHT.

  14. Facile synthesis of diazido-functionalized biaryl compounds as radioisotope-free photoaffinity probes by Suzuki-Miyaura coupling.

    PubMed

    Hosoya, Takamitsu; Inoue, Atsushi; Hiramatsu, Toshiyuki; Aoyama, Hiroshi; Ikemoto, Takaaki; Suzuki, Masaaki

    2009-03-15

    Suzuki-Miyaura coupling of 3-azido-5-(azidomethyl)phenylboronic acid pinacol ester with various aryl bromides affords corresponding diazido-functionalized biaryl compounds in good yields. This approach provides an easy access to radioisotope-free photoaffinity probes possessing biaryl structure. By using this method, we prepared a novel diazido-functionalized dantrolene analog, which showed selective inhibitory effect on physiological Ca(2+) release (PCR) from sarcoplasmic reticulum (SR) in mouse skeletal muscle without affecting Ca(2+)-induced Ca(2+) release (CICR).

  15. Insights on spin delocalization and spin polarization mechanisms in crystals of azido copper(II) dinuclear complexes through the electron spin density Source Function.

    PubMed

    Gatti, Carlo; Macetti, Giovanni; Lo Presti, Leonardo

    2017-08-01

    The Source Function (SF) tool was applied to the analysis of the theoretical spin density in azido Cu(II) dinuclear complexes, where the azido group, acting as a coupler between the Cu(II) cations, is linked to the metal centres either in an end-on or in an end-end fashion. Results for only the former structural arrangement are reported in the present paper. The SF highlights to which extent the magnetic centres contribute to determine the local spin delocalization and polarization at any point in the dimetallic complex and whether an atom or group of atoms of the ligands act in favour or against a given local spin delocalization/polarization. Ball-and-stick atomic SF percentage representations allow for a visualization of the magnetic pathways and of the specific role played by each atom along these paths, at given reference points. Decomposition of SF contributions in terms of a magnetic and of a relaxation component provides further insight. Reconstruction of partial spin densities by means of the Source Function has for the first time been introduced. At variance with the standard SF percentage representations, such reconstructions offer a simultaneous view of the sources originating from specific subsets of contributing atoms, in a selected molecular plane or in the whole space, and are therefore particularly informative. The SF tool is also used to evaluate the accuracy of the analysed spin densities. It is found that those obtained at the unrestricted B3LYP DFT level, relative to those computed at the CASSCF(6,6) level, greatly overestimate spin delocalization to the ligands, but comparatively underestimate magnetic connection (spin transmission) among atoms, along the magnetic pathways. As a consequence of its excessive spin delocalization, the UB3LYP method also overestimates spin polarization mechanisms between the paramagnetic centres and the ligands. Spin delocalization measures derived from the refinement of Polarized Neutron Diffraction data seem in

  16. Novel Azido-Iodo Photoaffinity Ligands for the Human Serotonin Transporter Based on the Selective Serotonin Reuptake Inhibitor (S)-Citalopram

    PubMed Central

    2015-01-01

    Three photoaffinity ligands (PALs) for the human serotonin transporter (hSERT) were synthesized based on the selective serotonin reuptake inhibitor (SSRI), (S)-citalopram (1). The classic 4-azido-3-iodo-phenyl group was appended to either the C-1 or C-5 position of the parent molecule, with variable-length linkers, to generate ligands 15, 22, and 26. These ligands retained high to moderate affinity binding (Ki = 24–227 nM) for hSERT, as assessed by [3H]5-HT transport inhibition. When tested against Ser438Thr hSERT, all three PALs showed dramatic rightward shifts in inhibitory potency, with Ki values ranging from 3.8 to 9.9 μM, consistent with the role of Ser438 as a key residue for high-affinity binding of many SSRIs, including (S)-citalopram. Photoactivation studies demonstrated irreversible adduction to hSERT by all ligands, but the reduced (S)-citalopram inhibition of labeling by [125I]15 compared to that by [125I]22 and [125I]26 suggests differences in binding mode(s). These radioligands will be useful for characterizing the drug–protein binding interactions for (S)-citalopram at hSERT. PMID:26153715

  17. Identification of a 23 kDa protein from maize photoaffinity-labelled with 5-azido-[7-3H]indol-3-ylacetic acid.

    PubMed Central

    Feldwisch, J; Zettl, R; Campos, N; Palme, K

    1995-01-01

    A 23 kDa protein (p23) was identified in microsomal extracts from maize coleoptiles by photoaffinity labelling with 5-azido-[7-3H]indol-3-ylacetic acid ([3H]N3IAA). Labelling of p23 was blocked by unlabelled IAA, N3IAA, indol-3-ylbutyric acid and indol-3-yl-lactate. In addition, labelling was efficiently decreased by tryptophan, as well as by the scavenger p-aminobenzoic acid. Labelling was, however, not affected by synthetic auxins such as 1-naphthylacetic acid or 2,4-dichlorophenoxyacetic acid. Competition data suggest that the label was probably bound via the indole ring, and hence labelling was not specific for auxins. The 23 kDa protein was solubilized from crude microsomes by extraction with Triton X-100 and purified to homogeneity by ion-exchange, size-exclusion and reversed-phase chromatography. After electroblotting, the amino acid sequences of the p23 N-terminus as well as the several tryptic peptides were obtained. Database comparisons revealed sequence identity with a maize manganese superoxide dismutase. We conclude that photoaffinity labelling of p23 was pseudo-affinity, and therefore the binding site for IAA is not specific. Images Figure 1 Figure 2 Figure 3 Figure 4 PMID:7848285

  18. Simian immunodeficiency virus (SIV) infection of infant rhesus macaques as a model to test antiretroviral drug prophylaxis and therapy: oral 3'-azido-3'-deoxythymidine prevents SIV infection.

    PubMed Central

    Van Rompay, K K; Marthas, M L; Ramos, R A; Mandell, C P; McGowan, E K; Joye, S M; Pedersen, N C

    1992-01-01

    The prophylactic and therapeutic properties of 3'-azido-3'-deoxythymidine (AZT) against simian immunodeficiency virus (SIV) infection were tested in four 3-month-old rhesus macaques. The infant monkeys were inoculated intravenously with a low dose (1 to 10 100% animal infectious doses) of uncloned SIVmac. The monkeys were treated orally with 50 mg of AZT per kg of body weight every 8 h; two animals were started on treatment 2 h prior to virus inoculation, and two animals were started on treatment 6 weeks later. All four animals were treated for a period of 6 to 10 weeks. Outward signs of AZT toxicity were absent, but a mild macrocytic anemia occurred soon after therapy was started and resolved shortly after it was discontinued. The two infants that were begun on AZT treatment 2 h prior to virus inoculation never became infected, as demonstrated by the inability to detect cell-free or cell-associated virus in the blood, proviral DNA in peripheral blood mononuclear cells, or anti-SIV antibodies. AZT administration over a 10-week period had no detectable effect on the course of disease in the two animals that were begun on treatment after the infection had been established. In addition to demonstrating the prophylactic effect of AZT against low-dose SIV exposure, the study demonstrated the ease with which infant rhesus macaques can be used for antiretroviral drug testing. Images PMID:1489181

  19. Novel Azido-Iodo Photoaffinity Ligands for the Human Serotonin Transporter Based on the Selective Serotonin Reuptake Inhibitor (S)-Citalopram.

    PubMed

    Kumar, Vivek; Yarravarapu, Nageswari; Lapinsky, David J; Perley, Danielle; Felts, Bruce; Tomlinson, Michael J; Vaughan, Roxanne A; Henry, L Keith; Lever, John R; Newman, Amy Hauck

    2015-07-23

    Three photoaffinity ligands (PALs) for the human serotonin transporter (hSERT) were synthesized based on the selective serotonin reuptake inhibitor (SSRI), (S)-citalopram (1). The classic 4-azido-3-iodo-phenyl group was appended to either the C-1 or C-5 position of the parent molecule, with variable-length linkers, to generate ligands 15, 22, and 26. These ligands retained high to moderate affinity binding (K(i) = 24-227 nM) for hSERT, as assessed by [(3)H]5-HT transport inhibition. When tested against Ser438Thr hSERT, all three PALs showed dramatic rightward shifts in inhibitory potency, with Ki values ranging from 3.8 to 9.9 μM, consistent with the role of Ser438 as a key residue for high-affinity binding of many SSRIs, including (S)-citalopram. Photoactivation studies demonstrated irreversible adduction to hSERT by all ligands, but the reduced (S)-citalopram inhibition of labeling by [(125)I]15 compared to that by [(125)I]22 and [(125)I]26 suggests differences in binding mode(s). These radioligands will be useful for characterizing the drug-protein binding interactions for (S)-citalopram at hSERT.

  20. Cloning and characterization of a glutathione S-transferase that can be photolabeled with 5-azido-indole-3-acetic acid.

    PubMed Central

    Bilang, J; Sturm, A

    1995-01-01

    Previously, we identified a soluble protein from Hyoscyamus muticus that was photolabeled by 5-azido-indole-3-acetic acid. This protein was determined to be a glutathione S-transferase (GST; J. Bilang, H. Macdonald, P.J. King, and A. Sturm [1993] Plant Physiol 102: 29-34). We have examined the effect of auxin on the activity of this H. muticus GST. Auxins reduced enzyme activity only at high concentrations, with 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid being more effective than indole-3-acetic acid (IAA) and naphthylacetic acid. IAA was a noncompetitive inhibitor, whereas inhibition by 2,4-D was competitive with respect to 1-chloro-2,4-dinitro-benzene. We also present the sequence of a full-length cDNA clone that codes for a GST and contains all partial amino acid sequences of the purified protein. The auxin-binding GST was found in high amounts in roots and stems and low amounts in leaves and flower buds. The steady-state mRNA level was not regulated by IAA or naphthylacetic acid, whereas 2,4-D and 2,3-dichlorophenoxyacetic acid increased mRNA levels. We propose a model in which 2,4-D is a substrate for GST, whereas IAA binds at a second site, known as a ligandin-binding site for the purpose of intracellular transport. PMID:7480325

  1. 3'-Azido-3'-deoxythymidine-induced reduction in the ability of uninfected CD4-expressing cells to participate in syncytium formation.

    PubMed Central

    Buckheit, R W; Germany-Decker, J; Qualls-Goodwin, K; Bowdon, B J; Shannon, W M

    1992-01-01

    A cocultivation assay system consisting of uninfected human T cells and cells chronically infected with human immunodeficiency virus type 1 has been used to investigate syncytium formation in short-term assays. Continuous treatment or short-term pretreatment of uninfected CD4-expressing human T-cell lines with 3'-azido-3'-deoxythymidine (AZT) reduces the ability of these cells to participate in syncytium formation when mixed with chronically infected cells. The effect of AZT on syncytium formation is observed both as a reduction in the number of syncytia and as a reduction in the size of the syncytia that are detected. This syncytium-reducing effect of AZT is dose and time dependent and does not result from a modulation of CD4 antigen expression on the cell surface of uninfected, treated cells. Maximum syncytium reduction is observed with the continuous presence of AZT; however, pretreatment for times as short as 15 min results in a significant reduction in syncytium formation. Since reverse transcription is not required for efficient syncytium formation, the syncytium-reducing effect of AZT on uninfected human cells may represent an antiviral property of AZT with important therapeutic potential. PMID:1355606

  2. Effect of 3'-azido-3'-deoxythymidine and 2',3'-dideoxyinosine on establishment of human immunodeficiency virus type 1 infection in cultured CD8+ lymphocytes.

    PubMed Central

    Mercure, L; Brenner, B J; Phaneuf, D; Tsoukas, C; Wainberg, M A

    1994-01-01

    Several groups have shown that peripheral CD8+ lymphocytes can be infected with human immunodeficiency virus type 1 (HIV-1), resulting in noncytopathic infection and persistent production of viral particles. We studied the ability of 3'-azido-3'-deoxythymidine (AZT) and 2',3'-dideoxyinosine (ddI) to inhibit the establishment of HIV-1 infection in CD8+ cells that were derived from cultures of peripheral blood lymphocytes exposed to both virus and drug. In situ infection of CD8+ cells was demonstrated by double flow cytometry analysis by using both anti-glycoprotein 120 (anti-gp120) and anti-CD8 monoclonal antibodies. At higher concentrations of drug (e.g., 0.4 microM AZT), the production of viral particles was inhibited for over 2 months, as assessed by p24 antigen levels in the culture medium. We also performed a time course experiment to determine whether HIV-1 infection of CD8+ cells would be affected by treatment of peripheral blood lymphocytes with AZT or ddI for different intervals following exposure to virus. Quantitative PCR revealed that 0.4 microM AZT, added as late as 24 h after infection, interfered with the formation of proviral DNA in CD8+ cells. Both HIV-1 load and the production of progeny virions by CD8+ cells, as monitored by reverse transcriptase activity in culture fluids, were inhibited by both AZT and ddI in a dose-dependent manner. Images PMID:8067781

  3. Effect of 3'-azido-3'-deoxythymidine and 2',3'-dideoxyinosine on establishment of human immunodeficiency virus type 1 infection in cultured CD8+ lymphocytes.

    PubMed

    Mercure, L; Brenner, B J; Phaneuf, D; Tsoukas, C; Wainberg, M A

    1994-05-01

    Several groups have shown that peripheral CD8+ lymphocytes can be infected with human immunodeficiency virus type 1 (HIV-1), resulting in noncytopathic infection and persistent production of viral particles. We studied the ability of 3'-azido-3'-deoxythymidine (AZT) and 2',3'-dideoxyinosine (ddI) to inhibit the establishment of HIV-1 infection in CD8+ cells that were derived from cultures of peripheral blood lymphocytes exposed to both virus and drug. In situ infection of CD8+ cells was demonstrated by double flow cytometry analysis by using both anti-glycoprotein 120 (anti-gp120) and anti-CD8 monoclonal antibodies. At higher concentrations of drug (e.g., 0.4 microM AZT), the production of viral particles was inhibited for over 2 months, as assessed by p24 antigen levels in the culture medium. We also performed a time course experiment to determine whether HIV-1 infection of CD8+ cells would be affected by treatment of peripheral blood lymphocytes with AZT or ddI for different intervals following exposure to virus. Quantitative PCR revealed that 0.4 microM AZT, added as late as 24 h after infection, interfered with the formation of proviral DNA in CD8+ cells. Both HIV-1 load and the production of progeny virions by CD8+ cells, as monitored by reverse transcriptase activity in culture fluids, were inhibited by both AZT and ddI in a dose-dependent manner.

  4. Studies on yeast nucleoside triphosphate-nucleoside diphosphate transphosphorylase (nucleoside diphosphokinase). IV. Steady-state kinetic properties with thymidine nucleotides (including 3'-azido-3'-deoxythymidine analogues).

    PubMed

    Kuby, S A; Fleming, G; Alber, T; Richardson, D; Takenaka, H; Hamada, M

    1991-01-01

    A study of the steady-state kinetics of the crystalline brewer's yeast (Saccharomyces carlsbergensis) nucleoside diphosphokinase, with the magnesium complexes of the adenine and thymidine nucleotides as reactants, has led to a postulated kinetic mechanism which proceeds through a substituted enzyme. This agrees with the earlier conclusions of Garces and Cleland [Biochemistry 1969; 8:633-640] who characterized a reaction between the magnesium complexes of the adenine and uridine nucleotides. An advantage of using thymidine nucleotides as reactants is that they permit accurate, rapid and continuous assays of the enzymatic activity in coupled-enzymatic tests. Through measurements of the initial velocities and product inhibition studies, the Michaelis constants, maximum velocities, and inhibition constants could be evaluated for the individual substrates. Competitive substrate inhibition was encountered at relatively high substrate concentrations, which also permitted an evaluation of their ability to act as 'dead-end' inhibitors. The Michaelis constants for the 3'-azido-3'-deoxythymidine (AzT) analogues were also evaluated and, although these values were only somewhat higher than those of their natural substrates, the Km's for the adenine nucleotides as paired substrates were lower and the Vmax's were drastically reduced. The pharmacological implications of these observations are touched upon and extrapolated to the cases where therapeutic doses of AzT may be employed.

  5. TRIFLUOROMETHYL COMPOUNDS OF GERMANIUM

    DTIC Science & Technology

    FLUORIDES, *GERMANIUM COMPOUNDS, *HALIDES, *ORGANOMETALLIC COMPOUNDS, ALKYL RADICALS, ARSENIC COMPOUNDS, CHEMICAL BONDS, CHEMICAL REACTIONS ...CHLORIDES, CHLORINE COMPOUNDS, HYDROLYSIS, IODIDES, METHYL RADICALS, POTASSIUM COMPOUNDS, PYROLYSIS, STABILITY, SYNTHESIS, TIN COMPOUNDS.

  6. Azido-(benzonitrile-κN)[hydrido-tris(pyrazol-1-yl-κN)borato](triphenyl-phosphine-κP)ruthenium(II).

    PubMed

    Huang, Chiung-Cheng; Chen, Han-Gung; Lo, Yih Hsing; Lai, Wen-Rong; Lin, Chia-Her

    2010-06-30

    Facile ligand substitution is observed when the ruthenium-azide complex, [RuN(3)(Tp)(PPh(3))(2)] [Tp,HB(pz)(3), pz = pyrazol-yl, PPh(3) = triphenyl-phosphine] is treated with benzo-nitrile, yielding the title compound, [Ru(C(9)H(10)BN(6))(N(3))(C(7)H(5)N)(C(18)H(15)P)]. The asymmetric unit contains two crystallographically independent mol-ecules. In each one, the Ru(II) atom is six-coordinated in a distorted octa-hedral geometry by five N atoms from an htpb ligand, an azide ligand and a benzonitrile ligand and one P atom from a triphenyl-phosphine (tpp) ligand. The azide group is almost linear and is coordinated to Ru with an average Ru-N-N angle of 124.9 (3)°.

  7. K-ras cancer gene mutations in lung tumors from female Swiss (CD-1) mice exposed transplacentally to 3'-azido-3'-deoxythymidine.

    PubMed

    Koujitani, Takatoshi; Ton, Tai-Vu T; Lahousse, Stephanie A; Hong, Hue-Hua L; Wakamatsu, Nobuko; Sills, Robert C

    2008-12-01

    A transplacental carcinogenicity study was conducted by exposing pregnant Swiss (CD-1) mice to 0, 50, 100, 200, or 300 mg 3'-azido-3'-deoxythymidine (AZT)/kg body weight (BW) daily for the duration of gestation (18-19 days) [National Toxicology Program,2006]. The incidence of alveolar/bronchiolar adenomas and carcinomas in the 200 and 300 mg/kg groups was significantly higher (P = 0.027 and 0.007, respectively) in male offspring, but not in females (P = 0.338 and 0.315, respectively). The purpose of the present study was to evaluate K-ras mutation status in lung tumors from the female offspring in AZT exposed groups and to determine whether at the molecular level there were signature K-ras mutations in lung tumors that were different from spontaneous tumors. K-ras mutation was detected by cycle sequencing of polymerase chain reaction (PCR)-amplified DNA, isolated from formalin-fixed, paraffin-embedded lung tumors. K-ras mutations were detected in 17 of 28 (61%) lung tumors from the female offspring in AZT exposed groups. No K-ras mutations were detected in the 8 tumors examined from the female control group. The predominant mutations were Codon 12 G-->T transversions in the 50, 100, and 300 mg/kg groups, and Codon 12 G-->C transversions in the 200 and 300 mg/kg groups. K-ras Codon 12 G-->T transversions (TGT mutations) may be induced by oxidative DNA damage and 8-oxoguanine (8-oxoG), while K-ras Codon 12 G-->C transversions (CGT mutations) may be due to further oxidative lesions of guanine and 8-oxoG.

  8. A trial with 3'-azido-2',3'-dideoxythymidine and human interferon-α in cats naturally infected with feline leukaemia virus.

    PubMed

    Stuetzer, Bianca; Brunner, Konstanze; Lutz, Hans; Hartmann, Katrin

    2013-08-01

    Feline leukaemia virus (FeLV) infection is still one of the leading causes of infection-related deaths in domestic cats. Treatment with various drugs has been attempted, but none has resulted in cure or complete virus elimination. Human interferon-α2a (huIFN-α2a) and 3'-azido-2',3'-dideoxythymidine (AZT) have been proven to decrease antigenaemia in cats infected experimentally with FeLV. The purpose of this study was to assess the efficacy of huIFN-α2a, AZT and a combination of both drugs in cats infected naturally with FeLV in a placebo-controlled double-blinded trial. Fourty-four FeLV-infected cats in which free FeLV p27 antigen was detected in serum by enzyme-linked immunosorbent assay were included in the study. Cats were assigned to one of four treatment groups that received either high dose huIFN-α2a (10(5) IU/kg q24h; 12 cats), AZT (5 mg/kg q12h; 10 cats, both of these treatments (12 cats) or placebo (10 cats). All cats were treated for 6 weeks. Clinical variables, including stomatitis, and laboratory parameters, such as CD4(+) and CD8(+) counts and serum FeLV p 27 antigen concentration, were recorded throughout the treatment period. No significant difference among the groups was observed during the treatment period for any of the parameters. Aside from anaemia in one cat treated with AZT, no adverse effects were observed. It was not possible to demonstrate efficacy of huIFN-α2a or AZT alone or together in cats infected naturally with FeLV when given according to this regimen for 6 weeks; however, no notable side effects were detected.

  9. 3′-AZIDO-3′-DEOXYTHYMIDINE (AZT) IS A COMPETITIVE INHIBITOR OF THYMIDINE PHOSPHORYLATION IN ISOLATED RAT HEART AND LIVER MITOCHONDRIA

    PubMed Central

    Lynx, Matthew D.; McKee, Edward E.

    2006-01-01

    Long-term use of 3′-azido-3′deoxythymidine (AZT) is associated with various tissue toxicities, including hepatotoxicity and cardiomyopathy, and with mitochondrial DNA depletion. AZT-5′-triphosphate (AZTTP) is a known inhibitor of the mitochondrial DNA polymerase γ and has been targeted as the source of the mitochondrial DNA depletion. However, in previous work from this laboratory with isolated rat heart and liver mitochondria, AZT itself was shown to be a more potent inhibitor of thymidine phosphorylation (IC50 of 7.0 ± 1.0 μM AZT in heart mitochondria and of 14.4 ± 2.6 μM AZT in liver mitochondria) than AZTTP is of polymerase γ (IC50 of >100 μM AZTTP), suggesting that depletion of mitochondrial stores of TTP may limit replication and could be the cause of the mitochondrial DNA depletion observed in tissues affected by AZT toxicity. The purpose of this work is to characterize the nature of AZT inhibition of thymidine phosphorylation in isolated rat heart and rat liver mitochondria. In both of these tissues, AZT was found to be a competitive inhibitor of the phosphorylation of thymidine to TMP, catalyzed by thymidine kinase 2. The inhibition constant (Ki) for heart mitochondria is 10.6 ± 4.5 μM AZT, and for liver mitochondria Ki is 14.0 ± 2.5 μM AZT. Since AZT is functioning as a competitive inhibitor, increasing thymidine concentrations may be one mechanism to overcome the inhibition and decrease AZT-related toxicity in these tissues. PMID:16720018

  10. 3′-Azido-3′-deoxythymidine (AZT) inhibits thymidine phosphorylation in isolated rat liver mitochondria: A possible mechanism of AZT hepatotoxicity

    PubMed Central

    Lynx, Matthew D.; Bentley, Alice T.; McKee, Edward E.

    2006-01-01

    3′-Azido-3′-deoxythymidine (AZT) is a staple of highly active antiretroviral therapy (HAART). Prior to HAART, long-term use of high-dosage AZT caused myopathy, cardiomyopathy, and hepatotoxicity, associated with mitochondrial DNA depletion. As a component of HARRT, AZT causes cytopenias and lipodystrophy. AZT-5′-triphosphate (AZTTP) is a known inhibitor of the mitochondrial polymerase γ and has been targeted as the source of the mitochondrial DNA depletion. However, in previous work from this laboratory with isolated rat heart mitochondria, AZT phosphorylation beyond AZT-5′-monophosphate (AZTMP) was not detected. Rather, AZT was shown to be a more potent inhibitor of thymidine phosphorylation (50% inhibitory concentration (IC50) of 7.0 ± 1.0 μM) than AZTTP is of polymerase γ (IC50 of >100 μM), suggesting that depletion of mitochondrial stores of TTP may limit replication. This work has investigated whether an identical mechanism might account for the hepatotoxicity seen with long-term use of AZT. Isolated rat liver mitochondria were incubated with labeled thymidine or AZT, and the rate and extent of phosphorylation were determined by HPLC analysis of acid-soluble extracts of the incubated mitochondria. The results showed that in the phosphorylation of thymidine to TMP, liver mitochondria exhibit a higher Vmax and Km than heart mitochondria, but otherwise heart and liver mitochondria display similar kinetics. AZT is phosphorylated to AZTMP, but no further phosphorylated forms were detected. In addition, AZT inhibited the production of TTP, with an IC50 of 14.4 ± 2.6 μM AZT. This is higher, but comparable to, the results seen in isolated rat heart mitochondria. PMID:16472780

  11. 5'-azido-N-1-naphthylphthalamic acid, a photolabile analog of the auxin transport inhibitor, N-1-naphthylphthalamic acid: synthesis and binding properties

    SciTech Connect

    Voet, J.G.; Howley, K.; Shumsky, J.S.

    1987-05-01

    The polar transport of the plant growth regulator, auxin (indole-3-acetic acid, IAAH), is thought to involve the participation of several proteins in the plasma membrane, including a specific, saturable, voltage independent H/sup +//IAA/sup -/ efflux carrier located preferentially at the basal end of each cell. Auxin transport is specifically inhibited by the herbicide, N-1-naphthylphthalamic acid (NPA), which binds specifically to a protein in the plasma membrane, thought to be either the IAA/sup -/ efflux carrier or an allosteric effector protein. They have synthesized and characterized a photolabile analog of NPA, 5'-azido-N-1-naphthylphthalamic acid (Az-NPA). This potential photoaffinity label for the NPA binding protein competes with /sup 3/H-NPA for binding sites on Curcurbita pepo L. (zucchini) stem cell membranes with K/sub j/ = 1.5 x 10/sup -7/ M. The K/sub i/ for NPA under these conditions is 2 x 10/sup -8/M, indicating that the affinity of Az-NPA for the membranes is only 7.5 fold lower than NPA. While the binding of 4.6 x 10/sup -6/ M Az-NPA to NPA binding sites is reversible in the dark, exposure to light results in a 30% loss in /sup 3/H-NPA binding ability. Pretreatment with 10/sup -4/ M NPA protects the membranes against photodestruction of /sup 3/H-NPA binding sites by Az-NPA, supporting the conclusion that Az-NPA destroys these sites by specific covalent attachment.

  12. 12-((5-Iodo-4-azido-2-hydroxybenzoyl)amino)dodecanoic acid: Biological recognition by cholesterol esterase and acyl-CoA:cholesterol O-acyltransferase

    SciTech Connect

    Kinnunen, P.M.; Klopf, F.H.; Bastiani, C.A.; Gelfman, C.M.; Lange, L.G. )

    1990-02-13

    Potential probes of protein cholesterol and fatty acid binding sites, namely, 12-((5-iodo-4-azido-2-hydroxybenzoyl)amino)dodecanoate (IFA) and its coenzyme A (IFA:CoA) and cholesteryl (IFA:CEA) esters, were synthesized. These radioactive, photoreactive lipid analogues were recognized as substrates and inhibitors of acyl-CoA;cholesterol O-acyltransferase (ACAT) and cholesterol esterase, neutral lipid binding enzymes which are key elements in the regulation of cellular cholesterol metabolism. In the dark, IFA reversibly inhibited cholesteryl ({sup 14}C)oleate hydrolysis by purified bovine pancreatic cholesterol esterase with an apparent K{sub i} of 150 {mu}M. Cholesterol esterase inhibition by IFA became irreversible after photolysis with UV light and oleic acid provided 50% protection against inactivation. Incubation of homogeneous bovine pancreatic cholesterol esterase with IFA:CEA resulted in its hydrolysis to IFA and cholesterol, indicating recognition of IFA:CEA as a substrate by cholesterol esterase. The coenzyme A ester, IFA:CoA, was a reversible inhibitor of microsomal ACAT activity under dark conditions, and photolysis resulted in irreversible inhibition of enzyme activity with 87% efficiency. IFA:CoA was also recognized as a substrate by both liver and aortic microsomal ACATs, with resultant synthesis of {sup 125}IFA:CEA. IFA and its derivatives, IFA:CEA and IFA:CoA, are thus inhibitors and substrates for cholesterol esterase and ACAT. Biological recognition of these photoaffinity lipid analogues will facilitate the identification and structural analysis of hitherto uncharacterized protein lipid binding sites.

  13. 5-Azido-2-aminopyridine, a new nitrene/nitrenium ion photoaffinity labeling agent that exhibits reversible intersystem crossing between singlet and triplet nitrenes.

    PubMed

    Panov, Maxim S; Voskresenska, Valentyna D; Ryazantsev, Mikhail N; Tarnovsky, Alexander N; Wilson, R Marshall

    2013-12-26

    The photochemistry of a new photoaffinity labeling (PAL) agent, 5-azido-2-(N,N-diethylamino)pyridine, was studied in aprotic and protic solvents using femtosecond-to-microsecond transient absorption and product analysis, in conjunction with ab initio multiconfigurational and multireference quantum chemical calculations. The excited singlet S1 state is spectroscopically dark, whereas photoexcitation to higher-lying singlet excited S2 and S3 states drives the photochemical reaction toward a barrierless ultrafast relaxation path via two conical intersections to S1, where N2 elimination leads to the formation of the closed-shell singlet nitrene. The singlet nitrene undergoes intersystem crossing (ISC) to the triplet nitrene in aprotic and protic solvents as well as protonation to form the nitrenium ion. The ISC rate constants in aprotic solvents increase with solvent polarity, displaying a "direct" gap effect, whereas an "inverse" gap effect is observed in protic solvents. Transient absorption actinometry experiments suggest that a solvent-dependent fraction from 20% to 50% of nitrenium ions is generated on a time scale of a few tens of picoseconds. The closed-shell singlet and triplet nitrene are separated by a small energy gap in protic solvents. As a result, the unreactive triplet state nitrene undergoes delayed, thermally activated reverse ISC to reform the reactive closed-shell singlet nitrene, which subsequently protonates, forming the remaining fraction of nitrenium ions. The product studies demonstrate that the resulting nitrenium ion stabilized by the electron-donating 4-amino group yields the final cross-linked product with high, almost quantitative efficiency. The enhanced PAL function of this new azide with respect to the widely applied 4-amino-3-nitrophenyl azide is discussed.

  14. PAWR-mediated suppression of BCL2 promotes switching of 3-azido withaferin A (3-AWA)-induced autophagy to apoptosis in prostate cancer cells

    PubMed Central

    Rah, Bilal; Rasool, Reyaz ur; Nayak, Debasis; Yousuf, Syed Khalid; Mukherjee, Debaraj; Kumar, Lekha Dinesh; Goswami, Anindya

    2015-01-01

    An active medicinal component of plant origin with an ability to overcome autophagy by inducing apoptosis should be considered a therapeutically active lead pharmacophore to control malignancies. In this report, we studied the effect of concentration-dependent 3-AWA (3-azido withaferin A) sensitization to androgen-independent prostate cancer (CaP) cells which resulted in a distinct switching of 2 interrelated conserved biological processes, i.e. autophagy and apoptosis. We have observed 3 distinct parameters which are hallmarks of autophagy in our studies. First, a subtoxic concentration of 3-AWA resulted in an autophagic phenotype with an elevation of autophagy markers in prostate cancer cells. This led to a massive accumulation of MAP1LC3B and EGFP-LC3B puncta coupled with gradual degradation of SQSTM1. Second, higher toxic concentrations of 3-AWA stimulated ER stress in CaP cells to turn on apoptosis within 12 h by elevating the expression of the proapoptotic protein PAWR, which in turn suppressed the autophagy-related proteins BCL2 and BECN1. This inhibition of BECN1 in CaP cells, leading to the disruption of the BCL2-BECN1 interaction by overexpressed PAWR has not been reported so far. Third, we provide evidence that pawr-KO MEFs exhibited abundant autophagy signs even at toxic concentrations of 3-AWA underscoring the relevance of PAWR in switching of autophagy to apoptosis. Last but not least, overexpression of EGFP-LC3B and DS-Red-BECN1 revealed a delayed apoptosis turnover at a higher concentration of 3-AWA in CaP cells. In summary, this study provides evidence that 3-AWA is a strong anticancer candidate to abrogate protective autophagy. It also enhanced chemosensitivity by sensitizing prostate cancer cells to apoptosis through induction of PAWR endorsing its therapeutic potential. PMID:25803782

  15. 2-Azido-( sup 32 P)NAD+, a photoactivatable probe for G-protein structure: Evidence for holotransducin oligomers in which the ADP-ribosylated carboxyl terminus of alpha interacts with both alpha and gamma subunits

    SciTech Connect

    Vaillancourt, R.R.; Dhanasekaran, N.; Johnson, G.L.; Ruoho, A.E. )

    1990-05-01

    A radioactive and photoactivatable derivative of NAD+, 2-azido-(adenylate-32P)NAD+, has been synthesized and used with pertussis toxin to ADP-ribosylate Cys347 of the alpha subunit (alpha T) of GT, the retinal guanine nucleotide-binding protein. ADP-ribosylation of alpha T followed by light activation of the azide moiety of 2-azido-(adenylate-32P)ADP-ribose produced four crosslinked species involving the alpha and gamma subunits of the GT heterotrimer: an alpha trimer (alpha-alpha-alpha), and alpha-alpha-gamma crosslink, an alpha dimer (alpha-alpha), and an alpha-gamma crosslink. The alpha trimer, alpha-alpha-gamma complex, alpha dimer, and alpha-gamma complexes were immunoreactive with alpha T antibodies. The alpha-alpha-gamma and the alpha-gamma complexes were immunoreactive with antisera recognizing gamma subunits. No evidence was found for crosslinking of alpha T to beta T subunits. Hydrolysis of the thioglycosidic bond between Cys347 and 2-azido-(adenylate-32P)ADP-ribose using mercuric acetate resulted in the transfer of radiolabel from Cys347 of alpha T in the crosslinked oligomers to alpha monomers, indicative of intermolecular photocrosslinking, and to gamma monomers, indicative of either intermolecular crosslinked complexes (between heterotrimers) or intramolecular crosslinked complexes (within the heterotrimer). These results demonstrate that GT exists as an oligomer and that ADP-ribosylated Cys347, which is four residues from the alpha T-carboxyl terminus, is oriented toward and in close proximity to the gamma subunit.

  16. Chiral Epoxides via Borane Reduction of 2-Haloketones Catalyzed By Spiroborate Ester: Application to the Synthesis of Optically Pure 1,2-Hydroxy Ethers and 1,2-Azido Alcohols

    PubMed Central

    Huang, Kun; Wang, Haiyang; Stepanenko, Viatcheslav; De Jesús, Melvin; Torruellas, Carilyn; Correa, Wildeliz; Ortiz-Marciales, Margarita

    2011-01-01

    An enantioselective borane-mediated reduction of a variety of 2-haloketones using 10% of spiroaminoborate ester 1 as catalyst is described. By a simple basic workup of 2-halohydrins, optically active epoxides are obtained in high yield and with excellent enantiopurity (up to 99% ee). Ring opening of oxiranes with phenoxides or sodium azide is investigated under different reaction conditions affording nonracemic 1,2-hydroxy ethers and 1,2-azido alcohols with excellent enantioselectivity (99% ee) and in good to high chemical yield. PMID:21294519

  17. Insecticidal quinazoline derivatives with (trifluoromethyl)diazirinyl and azido substituents as NADH:ubiquinone oxidoreductase inhibitors and candidate photoaffinity probes.

    PubMed

    Latli, B; Wood, E; Casida, J E

    1996-03-01

    Two candidate photoaffinity probes are designed from 4-substituted quinazolines known to be potent insecticides/acaricides and NADH:ubiquinone oxidoreductase inhibitors acting at or near the rotenone site. 4-(11-Azidoundecyl-2-amino)quinazoline, based on the undecylamino analog SAN 548A as a prototype, was synthesized in 18% overall yield from ethyl 10-undecenoate by oxidation of the terminal double bond, reductive amination, coupling to 4-chloroquinazoline, and functional group manipulation of the terminal ethyl ester to an alcohol, a mesylate and finally nucleophilic displacement with azide ions. 4-(4-(3-(Trifluoromethyl)-3H-diazirin-3-yl)phenethoxy)quinaz oline [the (trifluoromethyl)diazirinyl analog of fenazaquin insecticide/acaricide] was prepared from 4-bromophenethyl alcohol in 31% overall yield by first introducing the trifluoromethylketone moiety followed by its conversion to the (trifluoromethyl)-diazirine and finally coupling to 4-chloroquinazoline as above. Both candidate photoaffinity probes have the inhibitory potency of rotenone (IC50 of 3-4 nM in each case). The azidoundecylamino compound has inadequate photoreactivity whereas that of the (trifluoromethyl)diazirinyl analog is ideal at 350 nm. Radiosynthesis of the latter photoaffinity ligand included introduction of the diazirinyl moiety as the carbene precursor, oxidation of (trifluoromethyl)diazirinylphenethyl alcohol to the corresponding acid with Jones' reagent, and reduction of the phenacetyl chloride intermediate with sodium borotritide to incorporate tritium.

  18. Azido-(η(5)-penta-methyl-cyclo-penta-dien-yl)[2-(pyridin-2-yl)phen-yl]iridium(III).

    PubMed

    Ariyoshi, Keita; Suzuki, Takayoshi

    2013-01-01

    In the title compound, [Ir(C10H15)(C11H8N)(N3)], the Ir(III) ion is coordinated by three anionic ligands, namely, penta-methyl-cyclo-penta-dienyl (Cp*(-)), 2-(pyridin-2-yl)phenyl (ppy(-)) and azide (N3 (-)), and adopts a three-legged piano-stool geometry The coordination mode of N3 (-) is typical for Cp*Ir(III)-N3 complexes, with an Ir-N(N3) bond length of 2.125 (2) Å and an Ir-N=N bond angle of 116.5 (2)°. The N3 (-) ligand is almost linear [N=N=N = 176.0 (3)°], and the N=N bond length between the central and coordinating N atom and that between the central and non-coordinating terminal N atom are 1.194 (3) and 1.157 (3) Å, respectively. For the ppy(-) ligand, the Ir-C and Ir-N bond lengths are 2.066 (3) and 2.079 (3) Å, respectively, which are rather close to each other, compared to the related Ir(III)- or Rh(III)-ppy complexes. The Ir-C(Cp*) bond lengths vary in the range 2.163 (2)-2.232 (2) Å, indicating a strong trans influence of the cyclo-metallated C-donor atom of the ppy(-) ligand.

  19. Polybenzimidazole compounds

    DOEpatents

    Klaehn, John R.; Peterson, Eric S.; Wertsching, Alan K.; Orme, Christopher J.; Luther, Thomas A.; Jones, Michael G.

    2010-08-10

    A PBI compound that includes imidazole nitrogens, at least a portion of which are substituted with an organic-inorganic hybrid moiety. At least 85% of the imidazole nitrogens may be substituted. The organic-inorganic hybrid moiety may be an organosilane moiety, for example, (R)Me.sub.2SiCH.sub.2--, where R is selected from among methyl, phenyl, vinyl, and allyl. The PBI compound may exhibit similar thermal properties in comparison to the unsubstituted PBI. The PBI compound may exhibit a solubility in an organic solvent greater than the solubility of the unsubstituted PBI. The PBI compound may be included in separatory media. A substituted PBI synthesis method may include providing a parent PBI in a less than 5 wt % solvent solution. Substituting may occur at about room temperature and/or at about atmospheric pressure. Substituting may use at least five equivalents in relation to the imidazole nitrogens to be substituted or, preferably, about fifteen equivalents.

  20. Polybenzimidazole compounds

    SciTech Connect

    Klaehn, John R; Peterson, Eric S; Orme, Christopher J; Jones, Michael G; Wertsching, Alan K; Luther, Thomas A; Trowbridge, Tammy L

    2011-11-22

    A PBI compound includes imidazole nitrogens at least a portion of which are substituted with a moiety containing a carbonyl group, the substituted imidazole nitrogens being bonded to carbon of the carbonyl group. At least 85% of the nitrogens may be substituted. The carbonyl-containing moiety may include RCO--, where R is alkoxy or haloalkyl. The PBI compound may exhibit a first temperature marking an onset of weight loss corresponding to reversion of the substituted PBI that is less than a second temperature marking an onset of decomposition of an otherwise identical PBI compound without the substituted moiety. The PBI compound may be included in separatory media. A substituted PBI synthesis method may include providing a parent PBI in a less than 5 wt % solvent solution. Substituting may use more than 5 equivalents in relation to the imidazole nitrogens to be substituted.

  1. Polyazido Pyrimidines: High Energy Compounds and Precursors to Carbon Nanotubes (PREPRINT)

    DTIC Science & Technology

    2006-07-13

    CNTs. Among the catalysts explored e.g., Cu powder, Cu (OAc)2,25 AgNO3, Ni(ClO4)2, etc., we found that Ni(ClO4)2 was the best catalyst for the...formation comparable to 2,4,6-tri(azido)-1,3,5-triazine (3). Now we report the synthesis of a series of polyazidopyrimidine compounds, their...NaN3 ii) TMSN3 / SnCl2 N N Cl ClCl N N Cl ClCl Br N N N3 N3N3 N3 N N N3 N3N3 (9) (8) (10) (11) NaN3 NBS NaN3 Scheme 1. Synthesis of

  2. Rapid Grafting of Azido-labeled Oligo(ethylene glycol)s onto an Alkynyl-terminated Monolayer on Non-oxidized Silicon via Microwave-assisted “Click” Reaction

    PubMed Central

    Li, Yan; Wang, Jun; Cai, Chengzhi

    2011-01-01

    Microwave (MW) irradiation was used for the grafting of azido-labeled oligo(ethylene oxide) (OEG) on alkynyl-terminated non-oxidized silicon substrates via copper-catalyzed “click” reaction. The “clickable” monolayers were prepared by photografting of an α,ω-alkynene, where the alkynyl terminus was protected by a trimethylgermanyl (TMG) group, onto hydrogen-terminated Si(111) surfaces. X-ray photoelectron spectroscopy (XPS) was primarily employed to characterize the monolayers, and the data obtained were utilized to calculate the surface density of the TMG-alkynyl-functionalized substrate. MW-assisted one-pot deprotection/click reaction was optimized on the surfaces using azido-tagged OEG derivatives. Using MW instead of conventional heating led to a substantial improvement on the rate of the reaction while suppressing the oxidation of the silicon interface and OEG degradation. The antifouling property of the resulting substrates was evaluated using fibrinogen as a model protein. Results show that the OEG-modification reduced the protein adsorption by >90%. PMID:21306165

  3. Characterization of a phosphate binding domain on the alpha-subunit of chloroplast ATP synthase using the photoaffinity phosphate analogue 4-azido-2-nitrophenyl phosphate.

    PubMed

    Groth, G; Mills, D A; Christiansen, E; Richter, M L; Huchzermeyer, B

    2000-11-14

    The photoaffinity phosphate analogue 4-azido-2 nitrophenyl phosphate (ANPP) was shown previously (Pougeois, R., Lauquin, G. J.-M., and Vignais, P. V. (1983) Biochemistry 22, 1241-1245) to bind covalently and specifically to a single catalytic site on one of the three beta-subunits of the isolated chloroplast coupling factor 1 (CF(1)). Modification by ANPP strongly inhibited ATP hydrolysis activity. In this study, we examined labeling of membrane-bound CF(1) by ANPP by exposing thylakoid membranes to increasing concentrations of the reagent. ANPP exhibited saturable binding to two sites on CF(1), one on the beta-subunit and one on the alpha-subunit. Labeling by ANPP resulted in the complete inhibition of both ATP synthesis and ATP hydrolysis by the membrane-bound enzyme. Labeling of both sites by ANPP was reduced by more than 80% in the presence of P(i) (> or = 10 mM) and ATP (> or = 0.5 mM). ADP was less effective in competing with ANPP for binding, giving a maximum of approximately 35% inhibition at concentrations > or = 2 mM. ANPP-labeled tryptic peptides of the alpha-subunit were isolated and sequenced. The majority of the probe was contained in three peptides corresponding to residues Gln(173) to Arg(216), Gly(217) to Arg(253), and His(256) to Arg(272) of the alpha-subunit. In the mitochondrial F(1) (Abrahams, J. P., Leslie, A. G. W., Lutter, R., and Walker, J. E. (1994) Nature 370, 621-628), all three analogous peptides are located within the nucleotide binding pocket and within close proximity to the gamma-phosphate binding site. The data indicate, however, that the azidophenyl group of bound ANPP is oriented at approximately 180 degrees in the opposite direction to the adenine binding site with reference to the phosphate binding site on the alpha-subunit. The study has confirmed that ANPP is a bona fide phosphate analogue and suggests that it specifically targets the gamma-phosphate binding site within the nucleotide binding pockets on the alpha- and beta

  4. Multipurpose Compound

    NASA Technical Reports Server (NTRS)

    1983-01-01

    Specially formulated derivatives of an unusual basic compound known as Alcide may be the answer to effective treatment and prevention of the disease bovine mastitis, a bacterial inflammation of a cow's mammary gland that results in loss of milk production and in extreme cases, death. Manufactured by Alcide Corporation the Alcide compound has killed all tested bacteria, virus and fungi, shortly after contact, with minimal toxic effects on humans or animals. Alcide Corporation credits the existence of the mastitis treatment/prevention products to assistance provided the company by NERAC, Inc.

  5. Perfluorinated Compounds

    EPA Science Inventory

    Perfluorinated compounds such as the perfluoroalkyl acids (PFAAs) and their derivatives are important man-made chemicals that have wide consumer and industrial applications. They are relatively contemporary chemicals, being in use only since the 1950s, and until recently, have be...

  6. Perfluorinated Compounds

    EPA Science Inventory

    Perfluorinated compounds such as the perfluoroalkyl acids (PFAAs) and their derivatives are important man-made chemicals that have wide consumer and industrial applications. They are relatively contemporary chemicals, being in use only since the 1950s, and until recently, have be...

  7. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2003-01-01

    Seawater and natural brines accounted for about 60 percent of U.S. magnesium compounds production during 2002. Dead-burned and caustic-calcined magnesias were recovered from seawater by Premier Chemicals in Florida. They were also recovered from well brines in Michigan by Dow Chemical, Martin Marietta Magnesia Specialties and Rohm & Haas. And they were recovered from magnesite in Nevada by Premier Chemicals.

  8. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2006-01-01

    In 2005, seawater and natural brines accounted for 51% of US magnesium compounds production. World magnesia production was estimated to be 14.5 Mt. Most of the production came from China, North Korea, Russia and Turkey. Although no specific production figures are available, Japan and the United States are estimated to account for almost one-half of the world's capacity from seawater and brines.

  9. Looking for high energy density compounds applicable for propellant among the derivatives of DPO with -N3, -ONO2, and -NNO2 groups.

    PubMed

    Wang, Gui-Xiang; Gong, Xue-Dong; Liu, Yan; Du, Hong-Chen; Xu, Xiao-Juan; Xiao, He-Ming

    2011-04-15

    The derivatives of DPO (2,5-dipicryl-1,3,4-oxadiazole) are optimized to obtain their molecular geometries and electronic structures at the DFT-B3LYP/6-31G* level. The bond length is focused to primarily predict thermal stability and the pyrolysis mechanism of the title compounds. Detonation properties are evaluated using the modified Kamlet-Jacobs equations based on the calculated densities and heats of formation. It is found that there are good linear relationships between density, detonation velocity, detonation pressure, and the number of azido, nitrate, and nitramine groups. According to the largest exothermic principle, the relative specific impulse is investigated by calculating the enthalpy of combustion (ΔH(comb)) and the total heat capacity (C(p,gases)). It is found that the introduction of -N(3), -ONO(2), and -NNO(2) groups could increase the specific impulses and II-4, II-5, and III-5 are potential candidates for High Energy Density Materials (HEDMs). The effect of the azido, nitrate, and nitramine groups on the structure and the properties is discussed. Copyright © 2010 Wiley Periodicals, Inc.

  10. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2011-01-01

    Seawater and natural brines accounted for about 54 percent of U.S. magnesium compounds production in 2010. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Magnesia in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Magnesia. Intrepid Potash-Wendover and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma in Delaware and Premier Magnesia in Florida, and by Martin Marietta from its operation mentioned above.

  11. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2010-01-01

    Seawater and natural brines accounted for about 40 percent of U.S. magnesium compounds production in 2009. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Chemicals in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Chemicals. Intrepid Potash-Wendover, and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma in Delaware and Premier Chemicals in Florida, and by Martin Marietta from its operation mentioned above.

  12. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2002-01-01

    Seawater and natural brines accounted for about 60% of US magnesium compounds production in 2001. Dead-burned and caustic-calcined magnesias were recovered from seawater in Florida by Premier Chemicals. They were also recovered from Michigan well brines by Dow Chemical, Martin Marietta Magnesia Specialties and Rohm & Haas. And Premier Chemicals recovered dead-burned and caustic-calcined magnesias from magnesite in Nevada. Reilly Industries and Great Salt Lake Minerals recovered magnesium chloride brines from the Great Salt Lake in Utah.

  13. 5 prime -Azido-(3,6- sup 3 H sub 2 )-1-naphthylphthalamic acid, a photoactivatable probe for naphthylphthalamic acid receptor proteins from higher plants: Identification of a 23-kDa protein from maize coleoptile plasma membranes

    SciTech Connect

    Zettl, R.; Feldwisch, J.; Schell, J.; Palme, K. ); Boland, W. )

    1992-01-15

    1-Naphthylphthalamic acid (NPA) is a specific inhibitor of polar auxin transport that blocks carrier mediated auxin efflux from plant cells. To allow identification of the NPA receptor thought to be part of the auxin efflux carrier, the authors have synthesized a tritiated, photolabile NPA analogue, 5{prime}-azido-(3,6-{sup 3}H{sub 2})NPA (({sup 3}H{sub 2})N{sub 3}NPA). This analogue was used to identify NPA-binding proteins in fractions highly enriched for plasma membrane vesicles isolated from maize coleoptiles (Zea mays L.). Competition studies showed that binding of ({sup 3}H{sub 2})N{sub 3}NPA to maize plasma membrane vesicles was blocked by nonradioactive NPA but not by benzoic acid. After incubation of plasma membrane vesicles with ({sup 3}H{sub 2})N{sub 3}NPA and exposure to UV light, they observed specific photoaffinity labeling of a protein with an apparent molecular mass of 23 kDa. Pretreatment of the plasma membrane vesicles with indole-3-acetic acid or with the auxin-transport inhibitors NPA and 2,3,5-triiodobenzoic acid strongly reduced specific labeling of this protein. This 23-kDa protein was also labeled by addition of 5-azido-(7-{sup 3}H)indole-3-acetic acid to plasma membranes prior to exposure to UV light. The 23-kDa protein was solubilized from plasma membranes by 1% Triton X-100. The possibility that this 23-kDa polypeptide is part of the auxin efflux carrier system is discussed.

  14. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2007-01-01

    Seawater and natural brines accounted for about 52 percent of U.S. magnesium compounds production in 2006. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties from well brines in Michigan. Caustic-calcined magnesia was recovered from sea-water by Premier Chemicals in Florida; from well brines in Michigan by Martin Marietta and Rohm and Haas; and from magnesite in Nevada by Premier Chemicals. Intrepid Potash-Wendover and Great Salt Lake Minerals recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from brucite by Applied Chemical Magnesias in Texas, from seawater by SPI Pharma in Delaware and Premier Chemicals in Florida, and by Martin Marietta and Rohm and Haas from their operations mentioned above. About 59 percent of the magnesium compounds consumed in the United States was used for refractories that are used mainly to line steelmaking furnaces. The remaining 41 percent was consumed in agricultural, chemical, construction, environmental and industrial applications.

  15. Intermetallic Compounds

    NASA Astrophysics Data System (ADS)

    Takagiwa, Y.; Matsuura, Y.; Kimura, K.

    2014-06-01

    We have focused on the binary narrow-bandgap intermetallic compounds FeGa3 and RuGa3 as thermoelectric materials. Their crystal structure is FeGa3-type (tetragonal, P42/ mnm) with 16 atoms per unit cell. Despite their simple crystal structure, their room temperature thermal conductivity is in the range 4-5-W-m-1-K-1. Both compounds have narrow-bandgaps of approximately 0.3-eV near the Fermi level. Because their Seebeck coefficients are quite large negative values in the range 350-<-| S 373K|-<-550- μV-K-1 for undoped samples, it should be possible to obtain highly efficient thermoelectric materials both by adjusting the carrier concentration and by reducing the thermal conductivity. Here, we report the effects of doping on the thermoelectric properties of FeGa3 and RuGa3 as n and p-type materials. The dimensionless figure of merit, ZT, was significantly improved by substitution of Sn for Ga in FeGa3 (electron-doping) and by substitution of Zn for Ga in RuGa3 (hole-doping), mainly as a result of optimization of the electronic part, S 2 σ.

  16. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2012-01-01

    Seawater and natural brines accounted for about 57 percent of magnesium compounds produced in the United States in 2011. Dead-burned magnesia was produced by Martin Marietta Magnesia Specialties LLC from well brines in Michigan. Caustic-calcined magnesia was recovered from seawater by Premier Magnesia LLC in Florida, from well brines in Michigan by Martin Marietta and from magnesite in Nevada by Premier Magnesia. Intrepid Potash Wendover LLC and Great Salt Lake Minerals Corp. recovered magnesium chloride brines from the Great Salt Lake in Utah. Magnesium hydroxide was produced from seawater by SPI Pharma Inc. in Delaware and Premier Magnesia in Florida, and by Martin Marietta from its brine operation in Michigan.

  17. Bismaleimide compounds

    DOEpatents

    Adams, J.E.; Jamieson, D.R.

    1986-01-14

    Bismaleimides of the formula shown in the diagram wherein R[sub 1] and R[sub 2] each independently is H, C[sub 1-4]-alkyl, C[sub 1-4]-alkoxy, Cl or Br, or R[sub 1] and R[sub 2] together form a fused 6-membered hydrocarbon aromatic ring, with the proviso that R[sub 1] and R[sub 2] are not t-butyl or t-butoxy; X is O, S or Se; n is 1--3; and the alkylene bridging group, optionally, is substituted by 1--3 methyl groups or by fluorine, form polybismaleimide resins which have valuable physical properties. Uniquely, these compounds permit extended cure times, i.e., they remain fluid for a time sufficient to permit the formation of a homogeneous melt prior to curing.

  18. Bismaleimide compounds

    DOEpatents

    Adams, Johnnie E.; Jamieson, Donald R.

    1986-01-14

    Bismaleimides of the formula ##STR1## wherein R.sub.1 and R.sub.2 each independently is H, C.sub.1-4 -alkyl, C.sub.1-4 -alkoxy, C1 or Br, or R.sub.1 and R.sub.2 together form a fused 6-membered hydrocarbon aromatic ring, with the proviso that R.sub.1 and R.sub.2 are not t-butyl or t-butoxy; X is O, S or Se; n is 1-3; and the alkylene bridging group, optionally, is substituted by 1-3 methyl groups or by fluorine, form polybismaleimide resins which have valuable physical properties. Uniquely, these compounds permit extended cure times, i.e., they remain fluid for a time sufficient to permit the formation of a homogeneous melt prior to curing.

  19. Synthesis of 25-hydroxyvitamin D sub 3 3. beta. -3 prime -(N-(4-azido-2-nitrophenyl)amino)propyl ether, a second-generation photoaffinity analogue of 25-hydroxyvitamin D sub 3 : Photoaffinity labeling of rat serum vitamin D binding protein

    SciTech Connect

    Ray, R.; Holick, M.F. ); Bouillon, R.; Van Baelen, H. )

    1991-05-14

    Vulnerability of 25-hydroxy-(26,27-{sup 3}H)vitamin D{sub 3} 3{beta}-N-(4-azido-2-nitrophenyl)glycinate, a photoaffinity analogue of 25-hydroxyvitamin D{sub 3} (25-OH-D{sub 3}) toward standard conditions of carboxymethylationin promoted the authors to synthesize 25-hydroxyvitamin D{sub 3} 3{beta}-3{prime}-(N-(4-azido-2-nitrophenyl)amino)propyl ether (25-ANE), a hydrolytically stable photoaffinity analogue of 25-OH-D{sub 3}, and 25-hydroxyvitamin D{sub 3} 3{beta}-3{prime}-(N-(4-azido-2-nitro-(3,5-{sup 3}H)phenyl)amino)propyl ether ({sup 3}H-25-ANE), the radiolabeled counterpart of 25-ANE competes for the 25-OH-D{sub 3} binding site in rat serum vitamin D binding protein (rDBP). On the other hand, UV exposure of a sample of purified rat DBP (rDBP), preincubated in the dark with {sup 3}H-25-ANE, covalently labeled the protein. However, very little covalent labeling was observed in the absence of UV light or in the presence of a large excess of 25-OH-D{sub 3}. These results provide strong evidence for the covalent labeling of the 25-OH-D{sub 3} binding site in rDPB by {sup 3}H-25-ANE.

  20. Synthesis and promising properties of a new family of high-nitrogen compounds: polyazido- and polyamino-substituted N,N'-azo-1,2,4-triazoles.

    PubMed

    Qi, Cai; Li, Sheng-Hua; Li, Yu-Chuan; Wang, Yuan; Zhao, Xiu-Xiu; Pang, Si-Ping

    2012-12-14

    A new family of high-nitrogen compounds, that is, polyazido- and polyamino-substituted N,N'-azo-1,2,4-triazoles, were synthesized in a safe and convenient manner and fully characterized. The structures of 3,3',5,5'-tetra(azido)-4,4'-azo-1,2,4-triazole (15) and 3,3',5,5'-tetra(amino)-4,4'-azo-1,2,4-triazole (23) were also confirmed by X-ray diffraction. Differential scanning calorimetry (DSC) was performed to determine their thermal stability. Their heats of formation and density, which were calculated by using Gaussian 03, were used to determine the detonation performances of the related compounds (EXPLO 5.05). The heats of formation of the polyazido compounds were also derived by using an additive method. Compound 15 has the highest heat of formation (6933 kJ kg(-1)) reported so far for energetic compounds and a detonation performance that is comparable to that of octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), while compound 23 has a decomposition temperature of up to 290 °C.

  1. Arthrobacter aurescens TC1 Metabolizes Diverse s-Triazine Ring Compounds

    PubMed Central

    Strong, Lisa C.; Rosendahl, Charlotte; Johnson, Gilbert; Sadowsky, Michael J.; Wackett, Lawrence P.

    2002-01-01

    Arthrobacter aurescens strain TC1 was isolated without enrichment by plating atrazine-contaminated soil directly onto atrazine-clearing plates. A. aurescens TC1 grew in liquid medium with atrazine as the sole source of nitrogen, carbon, and energy, consuming up to 3,000 mg of atrazine per liter. A. aurescens TC1 is metabolically diverse and grew on a wider range of s-triazine compounds than any bacterium previously characterized. The 23 s-triazine substrates serving as the sole nitrogen source included the herbicides ametryn, atratone, cyanazine, prometryn, and simazine. Moreover, atrazine substrate analogs containing fluorine, mercaptan, and cyano groups in place of the chlorine substituent were also growth substrates. Analogs containing hydrogen, azido, and amino functionalities in place of chlorine were not growth substrates. A. aurescens TC1 also metabolized compounds containing chlorine plus N-ethyl, N-propyl, N-butyl, N-s-butyl, N-isobutyl, or N-t-butyl substituents on the s-triazine ring. Atrazine was metabolized to alkylamines and cyanuric acid, the latter accumulating stoichiometrically. Ethylamine and isopropylamine each served as the source of carbon and nitrogen for growth. PCR experiments identified genes with high sequence identity to atzB and atzC, but not to atzA, from Pseudomonas sp. strain ADP. PMID:12450818

  2. Azido-iodo-N-benzyl derivatives of threo-methylphenidate (Ritalin, Concerta): Rational design, synthesis, pharmacological evaluation, and dopamine transporter photoaffinity labeling.

    PubMed

    Lapinsky, David J; Velagaleti, Ranganadh; Yarravarapu, Nageswari; Liu, Yi; Huang, Yurong; Surratt, Christopher K; Lever, John R; Foster, James D; Acharya, Rejwi; Vaughan, Roxanne A; Deutsch, Howard M

    2011-01-01

    In contrast to tropane-based compounds such as benztropine and cocaine, non-tropane-based photoaffinity ligands for the dopamine transporter (DAT) are relatively unexplored. Towards addressing this knowledge gap, ligands were synthesized in which the piperidine nitrogen of 3- and 4-iodomethylphenidate was substituted with a benzyl group bearing a photoreactive azide. Analog (±)-3a demonstrated modest DAT affinity and a radioiodinated version was shown to bind covalently to rat striatal DAT and hDAT expressed in cultured cells. Co-incubation of (±)-3a with nonradioactive d-(+)-methylphenidate or (-)-2-β-carbomethoxy-3-β-(4-fluorophenyl)tropane (β-CFT, WIN-35,428, a cocaine analog) blocked DAT labeling. Compound (±)-3a represents the first successful example of a DAT photoaffinity ligand based on the methylphenidate scaffold. Such ligands are expected to assist in mapping non-tropane ligand-binding pockets within plasma membrane monoamine transporters.

  3. Azido-Iodo-N-Benzyl Derivatives of threo-Methylphenidate (Ritalin, Concerta): Rational Design, Synthesis, Pharmacological Evaluation, and Dopamine Transporter Photoaffinity Labeling

    PubMed Central

    Lapinsky, David J.; Velagaleti, Ranganadh; Yarravarapu, Nageswari; Liu, Yi; Huang, Yurong; Surratt, Christopher K.; Lever, John R.; Foster, James D.; Acharya, Rejwi; Vaughan, Roxanne A.; Deutsch, Howard M.

    2010-01-01

    In contrast to tropane-based compounds such as benztropine and cocaine, non-tropane-based photoaffinity ligands for the dopamine transporter (DAT) are relatively unexplored. Towards addressing this knowledge gap, ligands were synthesized in which the piperidine nitrogen of 3- and 4-iodomethylphenidate was substituted with a benzyl group bearing a photoreactive azide. Analog (±)-3a demonstrated modest DAT affinity and a radioiodinated version was shown to bind covalently to rat striatal DAT and hDAT expressed in cultured cells. Co-incubation of (±)-3a with nonradioactive D-(+)-methylphenidate or (−)-2-β-carbomethoxy-3-β-(4-fluorophenyl)tropane (β-CFT, WIN-35,428, a cocaine analog) blocked DAT labeling. Compound (±)-3a represents the first successful example of a DAT photoaffinity ligand based on the methylphenidate scaffold. Such ligands are expected to assist in mapping non-tropane ligand-binding pockets within plasma membrane monoamine transporters. PMID:21129986

  4. Preparation of a poly(3'-azido-3'-deoxythymidine-co-propargyl methacrylate-co-pentaerythritol triacrylate) monolithic column by in situ polymerization and a click reaction for capillary liquid chromatography of small molecules and proteins.

    PubMed

    Lin, Zian; Yu, Ruifang; Hu, Wenli; Zheng, Jiangnan; Tong, Ping; Zhao, Hongzhi; Cai, Zongwei

    2015-07-07

    Combining free radical polymerization with click chemistry via a copper-mediated azide/alkyne cycloaddition (CuAAC) reaction in a "one-pot" process, a facile approach was developed for the preparation of a poly(3'-azido-3'-deoxythymidine-co-propargyl methacrylate-co-pentaerythritol triacrylate) (AZT-co-PMA-co-PETA) monolithic column. The resulting poly(AZT-co-PMA-co-PETA) monolith showed a relatively homogeneous monolithic structure, good permeability and mechanical stability. Different ratios of monomers and porogens were used for optimizing the properties of a monolithic column. A series of alkylbenzenes, amides, anilines, and benzoic acids were used to evaluate the chromatographic properties of the polymer monolith in terms of hydrophobic, hydrophilic and cation-exchange interactions, and the results showed that the poly(AZT-co-PMA-co-PETA) monolith exhibited more flexible adjustment in chromatographic selectivity than that of the parent poly(PMA-co-PETA) and AZT-modified poly(PMA-co-PETA) monoliths. Column efficiencies for toluene, DMF, and formamide with 35,000-48,000 theoretical plates per m could be obtained at a linear velocity of 0.17 mm s(-1). The run-to-run, column-to-column, and batch-to-batch repeatabilities of the retention factors were less than 4.2%. In addition, the proposed monolith was also applied to efficient separation of sulfonamides, nucleobases and nucleosides, anesthetics and proteins for demonstrating its potential.

  5. Synthesis, in vitro and in vivo release kinetics, and anti-HIV activity of a sustained-release prodrug (mPEG-AZT) of 3'-azido-3'-deoxythymidine (AZT, Zidovudine).

    PubMed

    Li, Wenjun; Chang, Yu; Zhan, Peng; Zhang, Na; Liu, Xinyong; Pannecouque, Christophe; De Clercq, Erik

    2010-11-08

    A poly(ethylene glycol) (PEG) conjugate of 3'-azido-3'- deoxythymidine (AZT, zidovudine) was designed and synthesized as a novel sustained-release prodrug. In the synthetic process, a succinate diester spacer was used to covalently couple AZT with methoxy poly(ethylene glycol) (mPEG; MW=2000). The conjugate was characterized by Fourier transform infrared (FTIR) and NMR spectroscopies and matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry (MS). The in vitro release was determined in hydrochloride (HCl) solution (pH 1.2) and phosphate-buffered solution (PBS; pH 6.8), which showed the release rate of AZT from the conjugate was slower than that from the free drug, suggesting its possible increased retention in gastrointestinal conditions. Pharmacokinetic properties were evaluated experimentally by oral administration in mice. Compared to free AZT, the absorption half-life (t1/2ka) and elimination half life (t1/2ß) of AZT released from the conjugate were both extended to 0.51±0.03 h (p <0.01) and 2.94±0.24 h (p <0.01), respectively. Evaluation of the in vitro anti-HIV activities showed mPEG-AZT exhibited good inhibition of HIV-1, with an EC(50) value of 0.0634 μM, but it is lower than that of free AZT. These results show that the conjugate is capable of releasing the parent drug in a sustained profile, potentially providing a feasible alternative to oral administration of AZT in a clinical setting.

  6. Bis{bis­(azido-κN)bis­[bis­(pyridin-2-yl-κN)amine]cobalt(III)} sulfate dihydrate

    PubMed Central

    Setifi, Fatima; Knaust, Jacqueline M.; Setifi, Zouaoui; Touzani, Rachid

    2016-01-01

    The search for new mol­ecular materials with inter­esting magnetic properties, using the pseudohalide azide ion and di-2-pyridyl­amine (dpa, C10H9N3) as a chelating ligand, led to the synthesis and structure determination of the title compound, [Co(N3)2(dpa)2]2SO4·2H2O. The crystal structure comprises discrete [Co(dpa)2(N3)2]+ cations, sulfate anions, as well as H2O solvent mol­ecules. The CoIII cations display a slightly distorted octa­hedral coordination sphere defined by two N atoms from azide anions and four N atoms from the pyridyl rings of two dpa ligands. In the crystal, extensive C—H⋯O, N—H⋯O, and O—H⋯O inter­actions result in supra­molecular sheets that lie parallel to the ab plane. The sheets are further linked through O—H⋯N inter­actions between the water mol­ecules of one sheet and azide anions of another sheet, forming a supra­molecular framework. PMID:27375867

  7. Crystal structure of 4-(2-azido-phen-yl)-5-benzoyl-2-(1H-indol-3-yl)-1H-pyrrole-3-carbo-nitrile.

    PubMed

    Vimala, G; Raja, J Kamal; Naaz, Y Amina; Preumal, P T; SubbiahPandi, A

    2015-05-01

    In the title compound, C26H16N6O, the dihedral angles between the central pyrrole ring and the pendant indole ring system (r.m.s. deviation = 0.027 Å) and the azide-bearing benzene ring are 37.56 (8) and 51.62 (11)°, respectively. The azide group is almost coplanar with its attached benzene ring [C-C-N-N = 3.8 (3)°]. The benzoyl benzene ring is disordered over two orientations twisted with respect to each other by 9.29 (8)° in a 0.514 (2):0.486 (2) ratio. In the crystal, inversion dimers linked by pairs of Np-H⋯O (p = pyrrole) hydrogen bonds generate R 2 (2)(10) loops. A second inversion dimer arises from a pair of Ni-H⋯Nc (i = indole and c = cyanide) hydrogen bonds, which generates an R 2 (2)(16) loop. Together, the hydrogen bonds lead to [011] chains in the crystal.

  8. Azido­(η5-penta­methyl­cyclo­penta­dien­yl)[2-(pyridin-2-yl)phen­yl]iridium(III)

    PubMed Central

    Ariyoshi, Keita; Suzuki, Takayoshi

    2013-01-01

    In the title compound, [Ir(C10H15)(C11H8N)(N3)], the IrIII ion is coordinated by three anionic ligands, namely, penta­methyl­cyclo­penta­dienyl (Cp*−), 2-(pyridin-2-yl)phenyl (ppy−) and azide (N3 −), and adopts a three-legged piano-stool geometry The coordination mode of N3 − is typical for Cp*IrIII–N3 complexes, with an Ir—N(N3) bond length of 2.125 (2) Å and an Ir—N=N bond angle of 116.5 (2)°. The N3 − ligand is almost linear [N=N=N = 176.0 (3)°], and the N=N bond length between the central and coordinating N atom and that between the central and non-coordinating terminal N atom are 1.194 (3) and 1.157 (3) Å, respectively. For the ppy− ligand, the Ir—C and Ir—N bond lengths are 2.066 (3) and 2.079 (3) Å, respectively, which are rather close to each other, compared to the related IrIII– or RhIII–ppy complexes. The Ir—C(Cp*) bond lengths vary in the range 2.163 (2)–2.232 (2) Å, indicating a strong trans influence of the cyclo­metallated C-donor atom of the ppy− ligand. PMID:24098189

  9. Compounds affecting cholesterol absorption

    NASA Technical Reports Server (NTRS)

    Hua, Duy H. (Inventor); Koo, Sung I. (Inventor); Noh, Sang K. (Inventor)

    2004-01-01

    A class of novel compounds is described for use in affecting lymphatic absorption of cholesterol. Compounds of particular interest are defined by Formula I: ##STR1## or a pharmaceutically acceptable salt thereof.

  10. Dinitroso and polynitroso compounds

    PubMed Central

    Gowenlock, Brian G.; Richter-Addo, George B.

    2005-01-01

    The growing interest in the chemistry of C-nitroso compounds (RN=O; R = alkyl or aryl group) is due in part to the recognition of their participation in various metabolic processes of nitrogen-containing compounds. C-Nitroso compounds have a rich organic chemistry in their own right, displaying interesting intra- and intermolecular dimerization processes and addition reactions with unsaturated compounds. In addition, they have a fascinating coordination chemistry. While most of the attention has been directed towards C-nitroso compounds containing a single –NO moiety, there is an emerging area of research dealing with dinitroso and polynitroso compounds. In this critical review, we present and discuss the synthetic routes and properties of these relatively unexplored dinitroso and polynitroso compounds, and suggest areas of further development involving these compounds. (126 references.) PMID:16100619

  11. Toxicology and Carcinogenesis Studies of Mixtures of 3'-Azido-3'-Deoxythymidine (AZT), Lamivudine (3TC), and Nevirapine (NVP) (CAS Nos. 30516-87-1, 134678-17-4, 129618-40-2) in Genetically Modified C3B6.129F1-Trp53(tm1Brd) N12 Haploinsufficient Mice (in utero and postnatal gavage studies).

    PubMed

    2013-10-01

    , both the percentage of micronucleated RETs and the percentage of micronucleated NCEs were significantly increased in the group where 3TC was coadministered with AZT compared to the group administered only AZT. Under the conditions of this gavage study, there was clear evidence of carcinogenic activity of AZT alone in male heterozygous F1 p53+/- mice based on increased incidences of hepatocellular adenoma. There was clear evidence of carcinogenic activity of AZT in combination with 3TC, and AZT in combination with 3TC and NVP in male heterozygous F1 p53+/- mice based on increased incidences of hepatocellular adenoma and hepatocellular adenoma or carcinoma (combined). The occurrence of malignant lymphoma may have been related to treatment with AZT alone and with AZT in combination with 3TC. There was no evidence of carcinogenic activity of 3TC alone in male heterozygous F1 p53+/- mice administered 150 mg/kg. There was no evidence of carcinogenic activity of NVP alone in male heterozygous F1 p53+/- mice administered 168 mg/kg. There was equivocal evidence of carcinogenic activity of NVP alone, AZT in combination with 3TC, and AZT in combination with 3TC and NVP in female heterozygous F1 p53+/- mice based on the occurrence of malignant lymphoma. There was equivocal evidence of carcinogenic activity of 3TC alone in female heterozygous F1 p53+/- mice based on the occurrence of mammary gland adenoacanthoma or adenocarcinoma (combined). There was no evidence of carcinogenic activity of AZT alone in female heterozygous F1 p53+/- mice administered 240 mg/kg. Synonyms: (3'-AZIDO-3'-DEOXYTHYMIDINE) 3'-azido-2',3'-dideoxythymidine; azidodeoxythymidine; azidothymidine; 3'-azidothymidine; AZT; BW A509U; Compound S; 3'-deoxy-3'-azidothymidine; 3'-deoxy-(8CI) (9CI); ZDV; zidovudine. Trade name: Retrovir® [Combivir® with 3TC] Synonyms: (2',3'-DIDEOXY-3'-THIACYTIDINE) 3TC; 4-amino-1-[(2R,5S)-2-(hydroxymethyl)-1,3-oxathiolan-5-yl]-1,2-dihydropyrimidin-2-one; L-2',3'-dideoxy-3

  12. An in vivo mutation from leucine to tryptophan at position 210 in human immunodeficiency virus type 1 reverse transcriptase contributes to high-level resistance to 3'-azido-3'-deoxythymidine.

    PubMed Central

    Hooker, D J; Tachedjian, G; Solomon, A E; Gurusinghe, A D; Land, S; Birch, C; Anderson, J L; Roy, B M; Arnold, E; Deacon, N J

    1996-01-01

    Sequencing of the reverse transcriptase (RT) region of 26 human immunodeficiency virus type 1 (HIV-1) isolates from eight patients treated with 3'-azido-3'-deoxythymidine (AZT) revealed a mutation at codon 210 from TTG (leucine) to TGG (tryptophan) exclusively in association with resistance to AZT. The mutation Trp-210 was observed in 15 of the 20 isolates phenotypically resistant to AZT, being more commonly observed than resistance-associated mutations at codons 67, 70, and 219. Trp-210 was never observed before the emergence of resistance-associated mutations Leu-41 and Tyr-215, and in a sequential series of five isolates from one patient the order of emergence of mutations was found to be Tyr-215, Leu-41, and then Trp-210. Trp-210 was also found in association with the Leu-41, Asn-67, Arg-70, and Tyr-215 resistance genotype. To define the role of Trp-210 in AZT resistance, molecular HIV-1 clones were constructed with various combinations of RT mutations at codons 41, 67, 70, 210, and 215 and tested for susceptibility to AZT. In clones with polymerase genes derived either from HXB2-D or clinical isolates, Trp-210 alone did not increase AZT resistance, whereas in conjunction with Leu-41 and Tyr-215, Trp-210 contributed to high-level resistance (50% inhibitory concentration of >1 microM). In HXB2-D, Trp-210 with Tyr-215 generated a virus with resistance comparable to one with Leu-41, Tyr-215, and Trp-210. Inserting Trp-210 into the genetic context of mutations at codons 41, 67, 70, and 215 further enhanced resistance from a 50% inhibitory concentration of 1.44 microM to 8.41 microM. Molecular modeling of the tertiary structure of HIV-1 RT revealed that the distance between the side chains of Trp-210 (in helix alphaF) and Tyr-215 (in strand beta11a) approximated 4 A (1 A = 0.1 nm), sufficiently close to result in significant energetic interaction between these two aromatic side chains. In conclusion, Trp-210 contributes significantly to phenotypic AZT resistance of

  13. XAFS Model Compound Library

    DOE Data Explorer

    Newville, Matthew

    The XAFS Model Compound Library contains XAFS data on model compounds. The term "model" compounds refers to compounds of homogeneous and well-known crystallographic or molecular structure. Each data file in this library has an associated atoms.inp file that can be converted to a feff.inp file using the program ATOMS. (See the related Searchable Atoms.inp Archive at http://cars9.uchicago.edu/~newville/adb/) This Library exists because XAFS data on model compounds is useful for several reasons, including comparing to unknown data for "fingerprinting" and testing calculations and analysis methods. The collection here is currently limited, but is growing. The focus to date has been on inorganic compounds and minerals of interest to the geochemical community. [Copied, with editing, from http://cars9.uchicago.edu/~newville/ModelLib/

  14. Preparation of uranium compounds

    DOEpatents

    Kiplinger, Jaqueline L; Montreal, Marisa J; Thomson, Robert K; Cantat, Thibault; Travia, Nicholas E

    2013-02-19

    UI.sub.3(1,4-dioxane).sub.1.5 and UI.sub.4(1,4-dioxane).sub.2, were synthesized in high yield by reacting turnings of elemental uranium with iodine dissolved in 1,4-dioxane under mild conditions. These molecular compounds of uranium are thermally stable and excellent precursor materials for synthesizing other molecular compounds of uranium including alkoxide, amide, organometallic, and halide compounds.

  15. Nitrodifluoraminoterphenyl compounds and processes

    DOEpatents

    Lerom, M.W.; Peters, H.M.

    1975-07-08

    This patent relates to the nitrodifluoraminoterphenyl compounds: 3,3''-bis (difluoramino)-2,2'' 4,4', 4'',6,6',6''-octanitro-m-terphenyl (DDONT) and 3,3''-bis(difluoramino)-2,2',2''4,4',4'',6,6',6''-nonanitro-m-terphenyl (DDNONA). Procedures are described wherein diamino precursors of the indicated compounds are prepared and the final compounds are obtained by a fluorination operation. The compounds are highly energetic and suitable for use as explosives and particularly in exploding bridge wire (EBW) detonators. (auth)

  16. [Laboratory of Biopolymer Compounds].

    PubMed

    Ostapchuk, A M

    2008-01-01

    General information is presented concerning the Laboratory of Biological Polymeric Compounds at the Institute of Microbiology and Virology of the National Academy of Sciences of Ukraine; equipment, analytical and biophysical methods applied in the laboratory are listed.

  17. Heart testing compound

    DOEpatents

    Knapp, F.F. Jr.; Goodman, M.M.

    1983-06-29

    The compound 15-(p-(/sup 125/I)-iodophenyl)-6-tellurapentadecanoic acid is disclosed as a myocardial imaging agent having rapid and pronounced uptake, prolonged myocardial retention, and low in vivo deiodination.

  18. Polynitramino compounds outperform PETN.

    PubMed

    Joo, Young-Hyuk; Shreeve, Jean'ne M

    2010-01-07

    New polynitramino compounds were synthesized and fully characterized using IR and multinuclear ((1)H, (13)C, (15)N) NMR spectroscopy, and elemental analysis as well as single-crystal X-ray diffraction.

  19. Stabilized Lanthanum Sulphur Compounds

    NASA Technical Reports Server (NTRS)

    Reynolds, George H. (Inventor); Elsner, Norbert B. (Inventor); Shearer, Clyde H. (Inventor)

    1985-01-01

    Lanthanum sulfide is maintained in the stable cubic phase form over a temperature range of from 500 C to 1500 C by adding to it small amounts of calcium, barium. or strontium. This novel compound is an excellent thermoelectric material.

  20. Heart testing compound

    DOEpatents

    Knapp, Jr., Furn F.; Goodman, Mark M.

    1985-01-01

    The compound 15-(p-[.sup.125 I]-iodophenyl)-6-tellurapentadecanoic acid is disclosed as a myocardial imaging agent having rapid and pronounced uptake, prolonged myocardial retention, and low in vivo deiodination.

  1. Chemistry of peroxide compounds

    NASA Technical Reports Server (NTRS)

    Volnov, I. I.

    1981-01-01

    The history of Soviet research from 1866 to 1967 on peroxide compounds is reviewed. This research dealt mainly with peroxide kinetics, reactivity and characteristics, peroxide production processes, and more recently with superoxides and ozonides and emphasis on the higher oxides of group 1 and 2 elements. Solid state fluidized bed synthesis and production of high purity products based on the relative solubilities of the initial, intermediate, and final compounds and elements in liquid ammonia are discussed.

  2. Compound composite odontoma

    PubMed Central

    Girish, G; Bavle, Radhika M; Singh, Manish Kumar; Prasad, Sahana N

    2016-01-01

    The term odontoma has been used as a descriptor for any tumor of odontogenic origin. It is a growth in which both epithelial and mesenchymal cells exhibits complete differentiation. Odontomas are considered as hamartomas rather than true neoplasm. They are usually discovered on routine radiographic examination. Odontomas, according to the World Health Organization, are classified into complex odontoma and compound odontomas. The present paper reports a case of compound composite odontomas. PMID:27194882

  3. Compound composite odontoma.

    PubMed

    Girish, G; Bavle, Radhika M; Singh, Manish Kumar; Prasad, Sahana N

    2016-01-01

    The term odontoma has been used as a descriptor for any tumor of odontogenic origin. It is a growth in which both epithelial and mesenchymal cells exhibits complete differentiation. Odontomas are considered as hamartomas rather than true neoplasm. They are usually discovered on routine radiographic examination. Odontomas, according to the World Health Organization, are classified into complex odontoma and compound odontomas. The present paper reports a case of compound composite odontomas.

  4. Thermodynamics of Organic Compounds

    DTIC Science & Technology

    1979-01-01

    General Techniques for Combustion of Liquid/Soli. Organic Compounds by Oxygen Bomb Calorimetry by Arthur J. Head, William D. Good, and Ccrnelius...Mosselman, Chap. 8; Combustion of Liquid/Solid Organic Compounds with Non-Metallic Hetero-Atoms by Arthur J. Head and William D. Good, Chap. 9; in...0 Box 95085 Washington, DC 20234 Los Angeles, CA 90045 National Bureau of Standards CINDAS Chemical Thermodynamics Division Purdue University

  5. Structure and reactivity of a pyridine-1-imido-2-thiolato complex of iridium(III), CpIr(1-N-2-Spy), generated by photolysis of the (azido)(pyridine-2-thiolato) complex, CpIr(2-Spy)(N3).

    PubMed

    Sekioka, Yusuke; Kaizaki, Sumio; Mayer, James M; Suzuki, Takayoshi

    2005-11-14

    Photolysis of the (azido)(pyridine-2-thiolato)iridium(III) complex CpIr(2-Spy)(N3) (1) gave a pyridine-1-imido-2-thiolato complex, CpIr(1-N-2-Spy) (2), in which one of the nitrogen atoms of the azide ligand has been inserted into the Ir-N(py) bond (Cp = eta5-C5Me5). Complex 2 reacted quantitatively with methyl iodide to give the N-methylated product, [CpIr(1-NMe-2-Spy)]I (3). X-ray crystallography revealed that both 2 and 3 have similar two-legged piano stool structures with planar 1-N-2-Spy2- or 1-NMe-2-Spy- ligands, which form iridacyclopentadienyl-like rings by moderate S(ppi)/N(ppi) to Ir(dpi) pi donation.

  6. Phenolic Molding Compounds

    NASA Astrophysics Data System (ADS)

    Koizumi, Koji; Charles, Ted; de Keyser, Hendrik

    Phenolic Molding Compounds continue to exhibit well balanced properties such as heat resistance, chemical resistance, dimensional stability, and creep resistance. They are widely applied in electrical, appliance, small engine, commutator, and automotive applications. As the focus of the automotive industry is weight reduction for greater fuel efficiency, phenolic molding compounds become appealing alternatives to metals. Current market volumes and trends, formulation components and its impact on properties, and a review of common manufacturing methods are presented. Molding processes as well as unique advanced techniques such as high temperature molding, live sprue, and injection/compression technique provide additional benefits in improving the performance characterisitics of phenolic molding compounds. Of special interest are descriptions of some of the latest innovations in automotive components, such as the phenolic intake manifold and valve block for dual clutch transmissions. The chapter also characterizes the most recent developments in new materials, including long glass phenolic molding compounds and carbon fiber reinforced phenolic molding compounds exhibiting a 10-20-fold increase in Charpy impact strength when compared to short fiber filled materials. The role of fatigue testing and fatigue fracture behavior presents some insight into long-term reliability and durability of glass-filled phenolic molding compounds. A section on new technology outlines the important factors to consider in modeling phenolic parts by finite element analysis and flow simulation.

  7. Biodegradation of nitroaromatic compounds.

    PubMed

    Spain, J C

    1995-01-01

    Nitroaromatic compounds are released into the biosphere almost exclusively from anthropogenic sources. Some compounds are produced by incomplete combustion of fossil fuels; others are used as synthetic intermediates, dyes, pesticides, and explosives. Recent research revealed a number of microbial systems capable of transforming or biodegrading nitroaromatic compounds. Anaerobic bacteria can reduce the nitro group via nitroso and hydroxylamino intermediates to the corresponding amines. Isolates of Desulfovibrio spp. can use nitroaromatic compounds as their source of nitrogen. They can also reduce 2,4,6-trinitrotoluene to 2,4,6-triaminotoluene. Several strains of Clostridium can catalyze a similar reduction and also seem to be able to degrade the molecule to small aliphatic acids. Anaerobic systems have been demonstrated to destroy munitions and pesticides in soil. Fungi can extensively degrade or mineralize a variety of nitroaromatic compounds. For example, Phanerochaete chrysosporium mineralizes 2,4-dinitrotoluene and 2,4,6-trinitrotoluene and shows promise as the basis for bioremediation strategies. The anaerobic bacteria and the fungi mentioned above mostly transform nitroaromatic compounds via fortuitous reactions. In contrast, a number of nitroaromatic compounds can serve as growth substrates for aerobic bacteria. Removal or productive metabolism of nitro groups can be accomplished by four different strategies. (a) Some bacteria can reduce the aromatic ring of dinitro and trinitro compounds by the addition of a hydride ion to form a hydride-Meisenheimer complex, which subsequently rearomatizes with the elimination of nitrite. (b) Monooxygenase enzymes can add a single oxygen atom and eliminate the nitro group from nitrophenols. (c) Dioxygenase enzymes can insert two hydroxyl groups into the aromatic ring and precipitate the spontaneous elimination of the nitro group from a variety of nitroaromatic compounds. (d) Reduction of the nitro group to the corresponding

  8. Nonpost mold cure compound

    NASA Astrophysics Data System (ADS)

    Hirata, Akihiro

    1997-08-01

    The recent low price trend of electronic products has made IC manufacturing efficiency a top priority in the semiconductor industry. Post mold cure (PMC) process, which generally involves heating the packages in the oven at 175 C for 4 to 8 hours, takes up much longer time than most other assembly processes. If this PMC process can be reduced or eliminated, semiconductor makers will be rewarded with a much higher cost merit. We define the purpose of Non-PMC as 'to get high reliability with suitable physical and electrical properties without PMC'. We compared carious properties of molding compound before and after PMC. We found that curing reaction has almost complete through DSC and C-NMR measurement, but several properties have not stabilized yet, and that not all properties after PMC were better than before PMC. We developed new grade of molding compound considering these facts. And we found that main factors to accomplish non-PMC compound are curability and flowability, and more, increasing of fundamental properties. To accomplish non-PMC, at first, molding compound need to have very high curability. Generally speaking, too high curability causes low flowability, and causes incomplete filing, wire sweep, pad shift, and weak adhesion to inner parts of IC packages. To prevent these failures, various compound properties were studied, and we achieved in adding good flowability to very high curable molding compound. Finally, anti-popcorn property was improved by adding low moisture, high adhesion, high Tg, and high flexural strengths at high temperature. Through this study, we developed new compound grade for various package, especially large QFP using standard ECN resin.

  9. STATISTICAL DATA ON CHEMICAL COMPOUNDS.

    DTIC Science & Technology

    DATA STORAGE SYSTEMS, FEASIBILITY STUDIES, COMPUTERS, STATISTICAL DATA , DOCUMENTS, ARMY...CHEMICAL COMPOUNDS, INFORMATION RETRIEVAL), (*INFORMATION RETRIEVAL, CHEMICAL COMPOUNDS), MOLECULAR STRUCTURE, BIBLIOGRAPHIES, DATA PROCESSING

  10. Compound management beyond efficiency.

    PubMed

    Burr, Ian; Winchester, Toby; Keighley, Wilma; Sewing, Andreas

    2009-06-01

    Codeveloping alongside chemistry and in vitro screening, compound management was one of the first areas in research recognizing the need for efficient processes and workflows. Material management groups have centralized, automated, miniaturized and, importantly, found out what not to do with compounds. While driving down cost and improving quality in storage and processing, researchers still face the challenge of interfacing optimally with changing business processes, in screening groups, and with external vendors and focusing on biologicals in many companies. Here we review our strategy to provide a seamless link between compound acquisition and screening operations and the impact of material management on quality of the downstream processes. Although this is driven in part by new technologies and improved quality control within material management, redefining team structures and roles also drives job satisfaction and motivation in our teams with a subsequent positive impact on cycle times and customer feedback.

  11. Organic compounds in meteorites

    NASA Technical Reports Server (NTRS)

    Anders, E.; Hayatsu, R.; Studier, M. H.

    1973-01-01

    The problem of whether organic compounds originated in meteorites as a primary condensate from a solar gas or whether they were introduced as a secondary product into the meteorite during its residence in a parent body is examined by initially attempting to reconstruct the physical conditions during condensation (temperature, pressure, time) from clues in the inorganic matrix of the meteorite. The condensation behavior of carbon under these conditions is then analyzed on the basis of thermodynamic calculations, and compounds synthesized in model experiments on the condensation of carbon are compared with those actually found in meteorites. Organic compounds in meteorites seem to have formed by catalytic reactions of carbon monoxide, hydrogen, and ammonia in the solar nebula at 360 to 400 K temperature and about 3 to 7.6 microtorr pressure. The onset of these reactions was triggered by the formation of suitable catalysts (magnetite, hydrated silicates) at these temperatures.

  12. Metalloid compounds as drugs

    PubMed Central

    Sekhon, B. S.

    2013-01-01

    The six elements commonly known as metalloids are boron, silicon, germanium, arsenic, antimony, and tellurium. Metalloid containing compounds have been used as antiprotozoal drugs. Boron-based drugs, the benzoxaboroles have been exploited as potential treatments for neglected tropical diseases. Arsenic has been used as a medicinal agent and arsphenamine was the main drug used to treat syphilis. Arsenic trioxide has been approved for the treatment of acute promyelocytic leukemia. Pentavalent antimonials have been the recommended drug for visceral leishmaniasis and cutaneous leishmaniasis. Tellurium (IV) compounds may have important roles in thiol redox biological activity in the human body, and ammonium trichloro (dioxoethylene-O, O’-)tellurate (AS101) may be a promising agent for the treatment of Parkinson’s disease. Organosilicon compounds have been shown to be effective in vitro multidrug-resistance reverting agents. PMID:24019824

  13. Sulfur compounds in coal

    NASA Technical Reports Server (NTRS)

    Attar, A.; Corcoran, W. H.

    1977-01-01

    The literature on the chemical structure of the organic sulfur compounds (or functional groups) in coal is reviewed. Four methods were applied in the literature to study the sulfur compounds in coal: direct spectrometric and chemical analysis, depolymerization in drastic conditions, depolymerization in mild conditions, and studies on simulated coal. The data suggest that most of the organic sulfur in coal is in the form of thiophenic structures and aromatic and aliphatic sulfides. The relative abundance of the sulfur groups in bituminous coal is estimated as 50:30:20%, respectively. The ratio changes during processing and during the chemical analysis. The main effects are the transformation during processing of sulfides to the more stable thiophenic compounds and the elimination of hydrogen sulfide.

  14. [Energies of organic compounds

    SciTech Connect

    1995-07-01

    The first part of our study of the enthalpy of reduction of carbonyl compounds has been completed and includes four aldehydes, acetone, a series of cyclic ketones and ethyl acetate. Results suggest that some of the literature data for these compounds are significantly in error. Equilibrium constants have been measured for the reaction of carbonyl compounds with water to give hydrates as well as with methanol to give either hemiacetals or acetals. They cover a wide range, and studies are underway to determine the reasons for the differences. Studies of the enthalpies of hydration of some alkenes which yield tertiary alcohols have been completed, as well as a study of the hydrolysis of lactones. The ``gauche effect`` has been studied, and has been shown to result from the formation of bent bonds when atoms of much different electronegativity are joined.

  15. Sulfur compounds in coal

    NASA Technical Reports Server (NTRS)

    Attar, A.; Corcoran, W. H.

    1977-01-01

    The literature on the chemical structure of the organic sulfur compounds (or functional groups) in coal is reviewed. Four methods were applied in the literature to study the sulfur compounds in coal: direct spectrometric and chemical analysis, depolymerization in drastic conditions, depolymerization in mild conditions, and studies on simulated coal. The data suggest that most of the organic sulfur in coal is in the form of thiophenic structures and aromatic and aliphatic sulfides. The relative abundance of the sulfur groups in bituminous coal is estimated as 50:30:20%, respectively. The ratio changes during processing and during the chemical analysis. The main effects are the transformation during processing of sulfides to the more stable thiophenic compounds and the elimination of hydrogen sulfide.

  16. Organic compounds in meteorites

    NASA Technical Reports Server (NTRS)

    Anders, E.; Hayatsu, R.; Studier, M. H.

    1973-01-01

    The problem of whether organic compounds originated in meteorites as a primary condensate from a solar gas or whether they were introduced as a secondary product into the meteorite during its residence in a parent body is examined by initially attempting to reconstruct the physical conditions during condensation (temperature, pressure, time) from clues in the inorganic matrix of the meteorite. The condensation behavior of carbon under these conditions is then analyzed on the basis of thermodynamic calculations, and compounds synthesized in model experiments on the condensation of carbon are compared with those actually found in meteorites. Organic compounds in meteorites seem to have formed by catalytic reactions of carbon monoxide, hydrogen, and ammonia in the solar nebula at 360 to 400 K temperature and about 3 to 7.6 microtorr pressure. The onset of these reactions was triggered by the formation of suitable catalysts (magnetite, hydrated silicates) at these temperatures.

  17. Biodegradation of perfluorinated compounds.

    PubMed

    Parsons, John R; Sáez, Monica; Dolfing, Jan; de Voogt, Pim

    2008-01-01

    The information available in the literature provides evidence for the biodegradation of some poly- and per-fluorinated compounds, but such biodegradation is incomplete and may not result in mineralization. Recent publications have demonstrated that 8:2 fluorotelomer alcohol, for example, can be degraded by bacteria from soil and wastewater treatment plants to perfluorooctanoic acid. Similarly, 2-N-ethyl(perfluorooctane sulfonamido)ethanol can be degraded by wastewater treatment sludge to perfluorooctanesulfonate. It is presently unclear whether these two products are degraded further. Therefore, the question remains as to whether there is a potential for defluorination and biodegradation of PFCs that contributes significantly to their environmental fate. The lack of mineralization observed is probably caused by the stability of the C-F bond, although there are examples of microbially catalyzed defluorination reactions. As is the case with reductive dechlorination or debromination, reductive defluorination is energetically favorable under anaerobic conditions and releases more energy than that available from sulfate reduction or methanogenesis. Consequently, we should consider the possibility that bacteria will adapt to utilize this source of energy, although evolving mechanisms to overcome the kinetic barriers to degradation of these compounds may take some time. The fact that such reactions are absent for some PFCs, to date, may be because too little time has passed for microorganisms to adapt to these potential substrates. Hence, the situation may be comparable to that of chlorinated organic compounds several decades ago. For many years, organochlorine compounds were considered to be catabolically recalcitrant; today, reductive chlorination reactions of many organochlorines, including PCBs and dioxins, are regularly observed in anaerobic environments. Hence, it is opportune and important to continue studying the potential degradation of perfluorinated compounds

  18. Microoptical compound lens

    DOEpatents

    Sweatt, William C.; Gill, David D.

    2007-10-23

    An apposition microoptical compound lens comprises a plurality of lenslets arrayed around a segment of a hollow, three-dimensional optical shell. The lenslets collect light from an object and focus the light rays onto the concentric, curved front surface of a coherent fiber bundle. The fiber bundle transports the light rays to a planar detector, forming a plurality of sub-images that can be reconstructed as a full image. The microoptical compound lens can have a small size (millimeters), wide field of view (up to 180.degree.), and adequate resolution for object recognition and tracking.

  19. Prediction of intermetallic compounds

    NASA Astrophysics Data System (ADS)

    Burkhanov, Gennady S.; Kiselyova, N. N.

    2009-06-01

    The problems of predicting not yet synthesized intermetallic compounds are discussed. It is noted that the use of classical physicochemical analysis in the study of multicomponent metallic systems is faced with the complexity of presenting multidimensional phase diagrams. One way of predicting new intermetallics with specified properties is the use of modern processing technology with application of teaching of image recognition by the computer. The algorithms used most often in these methods are briefly considered and the efficiency of their use for predicting new compounds is demonstrated.

  20. PERSISTENT PERFLUORINATED ORGANIC COMPOUNDS

    EPA Science Inventory

    Perfluorinated compounds (PFCs) have gained notoriety in the recent past. Global distribution of PFCs in wildlife, environmental samples and humans has sparked a recent increase in new investigations concerning PFCs. Historically PFCs have been used in a wide variety of consume...

  1. Compound floating pivot micromechanisms

    DOEpatents

    Garcia, Ernest J.

    2001-04-24

    A new class of tilting micromechanical mechanisms have been developed. These new mechanisms use compound floating pivot structures to attain far greater tilt angles than are practical using other micromechanical techniques. The new mechanisms are also capable of bi-directional tilt about multiple axes.

  2. Urinary Compounds in Autism

    ERIC Educational Resources Information Center

    Alcorn, A.; Berney, T.; Bretherton, K.; Mills, M.; Savery, D.; Shattock, P.

    2004-01-01

    Although earlier claims to identify specific compounds in the urine of people with autism had been discredited, it was subsequently suggested that there might be biochemical characteristics that were specific to early childhood, particularly in those who also did not have a severe degree of intellectual disability This study was to establish…

  3. Barium and Compounds

    Integrated Risk Information System (IRIS)

    Barium and Compounds ; CASRN 7440 - 39 - 3 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinog

  4. Lead and compounds (inorganic)

    Integrated Risk Information System (IRIS)

    Lead and compounds ( inorganic ) ; CASRN 7439 - 92 - 1 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for

  5. Fun with Ionic Compounds

    ERIC Educational Resources Information Center

    Logerwell, Mollianne G.; Sterling, Donna R.

    2007-01-01

    Ionic bonding is a fundamental topic in high school chemistry, yet it continues to be a concept that students struggle to understand. Even if they understand atomic structure and ion formation, it can be difficult for students to visualize how ions fit together to form compounds. This article describes several engaging activities that help…

  6. Selenium and Compounds

    Integrated Risk Information System (IRIS)

    Selenium and Compounds ; CASRN 7782 - 49 - 2 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcin

  7. Fun with Ionic Compounds

    ERIC Educational Resources Information Center

    Logerwell, Mollianne G.; Sterling, Donna R.

    2007-01-01

    Ionic bonding is a fundamental topic in high school chemistry, yet it continues to be a concept that students struggle to understand. Even if they understand atomic structure and ion formation, it can be difficult for students to visualize how ions fit together to form compounds. This article describes several engaging activities that help…

  8. Energies of organic compounds

    SciTech Connect

    Wiberg, K.B.

    1995-07-01

    The studies included hydrolysis of ketals, hydration of alkenes, barrier to rotation about C-O bonds in esters and acids, hydrolysis of lactones, reduction of ketones, non-bonded interactions, and enthalpies of vaporization of ketones, ketals, and other compounds.

  9. Boron and Compounds

    Integrated Risk Information System (IRIS)

    EPA 635 / 04 / 052 www.epa.gov / iris TOXICOLOGICAL REVIEW OF BORON AND COMPOUNDS ( CAS No . 7440 - 42 - 8 ) In Support of Summary Information on the Integrated Risk Information System ( IRIS ) June 2004 U.S . Environmental Protection Agency Washington , DC DISCLAIMER This document has been reviewed

  10. Zinc and Compounds

    Integrated Risk Information System (IRIS)

    EPA / 635 / R - 05 / 002 TOXICOLOGICAL REVIEW OF ZINC AND COMPOUNDS ( CAS No . 7440 - 66 - 6 ) In Support of Summary Information on the Integrated Risk Information System ( IRIS ) July 2005 U.S . Environmental Protection Agency Washington D.C . DISCLAIMER This document has been reviewed in accordanc

  11. Beryllium and compounds

    Integrated Risk Information System (IRIS)

    EPA / 635 / R - 98 / 008 TOXICOLOGICAL REVIEW OF BERYLLIUM AND COMPOUNDS ( CAS No . 7440 - 41 - 7 ) In Support of Summary Information on the Integrated Risk Information System ( IRIS ) April 1998 U.S . Environmental Protection Agency Washington , DC DISCLAIMER This document has been reviewed in acco

  12. A stable argon compound

    PubMed

    Khriachtchev; Pettersson; Runeberg; Lundell; Rasanen

    2000-08-24

    The noble gases have a particularly stable electronic configuration, comprising fully filled s and p valence orbitals. This makes these elements relatively non-reactive, and they exist at room temperature as monatomic gases. Pauling predicted in 1933 that the heavier noble gases, whose valence electrons are screened by core electrons and thus less strongly bound, could form stable molecules. This prediction was verified in 1962 by the preparation of xenon hexafluoroplatinate, XePtF6, the first compound to contain a noble-gas atom. Since then, a range of different compounds containing radon, xenon and krypton have been theoretically anticipated and prepared. Although the lighter noble gases neon, helium and argon are also expected to be reactive under suitable conditions, they remain the last three long-lived elements of the periodic table for which no stable compound is known. Here we report that the photolysis of hydrogen fluoride in a solid argon matrix leads to the formation of argon fluorohydride (HArF), which we have identified by probing the shift in the position of vibrational bands on isotopic substitution using infrared spectroscopy. Extensive ab initio calculations indicate that HArF is intrinsically stable, owing to significant ionic and covalent contributions to its bonding, thus confirming computational predictions that argon should form a stable hydride species with properties similar to those of the analogous xenon and krypton compounds reported before.

  13. 8-fluoropurine compounds

    SciTech Connect

    Barrio, Jorge R.; Satyamurthy, Nagichettiar; Namavari, Mohammad; Phelps, Michael E.

    2001-01-01

    An efficient, regiocontrolled approach to the synthesis of 8-fluoropurines by direct fluorination of purines with dilute elemental fluorine, or acetyl hypofluorite, is provided. In a preferred embodiment, a purine compound is dissolved in a polar solvent and reacted with a dilute mixture of F.sub.2 in He or other inert gas.

  14. Urinary Compounds in Autism

    ERIC Educational Resources Information Center

    Alcorn, A.; Berney, T.; Bretherton, K.; Mills, M.; Savery, D.; Shattock, P.

    2004-01-01

    Although earlier claims to identify specific compounds in the urine of people with autism had been discredited, it was subsequently suggested that there might be biochemical characteristics that were specific to early childhood, particularly in those who also did not have a severe degree of intellectual disability This study was to establish…

  15. Aminopropyl thiophene compounds

    DOEpatents

    Goodman, Mark M.; Knapp, Jr., Furn F.

    1990-01-01

    Radiopharmaceuticals useful in brain imaging comprising radiohalogenated thienylethylamine derivatives. The compounds are 5-halo-thiophene-2-isopropyl amines able to cross the blood-brain barrier and be retained for a sufficient length of time to allow the evaluation of regional blood flow by radioimaging of the brain.

  16. Toxicity of dipyridyl compounds and related compounds.

    PubMed

    Li, Shenggang; Crooks, Peter A; Wei, Xiaochen; de Leon, Jose

    2004-01-01

    Five dipyridyl isomers, 2,2'-, 2,3'-, 2,4'-, 3,3'-, and 4,4'-dipyridyl, are products resulting from the pyrolytic degradation of tobacco products and degradation of the herbicide paraquat, and therefore may be present in the environment. In this article, the toxicological properties of these dipyridyl isomers in humans and animals are reviewed. Epidemiological studies suggest that cancerous skin lesions in workers involved in the manufacturing of paraquat may be associated with exposure to dipyridyl compounds. Experimental animal studies suggest that dipyridyl isomers may have several toxicological effects. Three of the dipyridyl isomers (the 2,2', 2,4', and 4,4' isomers) appear to be inducers of some metabolic enzymes. The 2,2'-dipyridyl isomer, an iron chelator, appears to influence vasospasm in primate models of stroke. The cytotoxic effects of 2,2'-dipyridyl on several leukemia cell lines have been reported, and a potent teratogenic effect of 2,2'-dipyridyl has been observed in rats. Based on the results of paraquat studies in experimental animal models, it has been proposed that paraquat may have deleterious effects on dopaminergic neurons. These findings support the epidemiological evidence that paraquat exposure may be associated with the development of Parkinson's disease. Studies designed to determine an association between paraquat exposure and Parkinson's disease are complicated by the possibility that metabolic changes may influence the neurotoxicity of paraquat and/or its metabolites. Preliminary unpublished data in mice show that 300-mg/kg doses of 2,2'-dipyridyl are neurotoxic, and 300-mg/kg doses of 2,4'- and 4,4'-dipyridyls are lethal. These results are consistent with earlier studies in Sherman rats using high 2,2'- and 4,4'-dipyridyl doses. New studies are needed to further explore the toxicological properties of dipyridyls and their potential public health impact.

  17. Organic compounds in meteorites

    NASA Technical Reports Server (NTRS)

    Lawless, J. G.

    1980-01-01

    Recent studies of carbonaceous chondrites provide evidence that certain organic compounds are indigenous and the result of an abiotic, chemical synthesis. The results of several investigators have established the presence of amino acids and precursors, mono- and dicarboxylic acids, N-heterocycles, and hydrocarbons as well as other compounds. For example, studies of the Murchison and Murray meteorites have revealed the presence of at least 40 amino acids with nearly equal abundances of D and L isomers. The population consists of both protein and nonprotein amino acids including a wide variety of linear, cyclic, and polyfunctional types. Results show a trend of decreasing concentration with increasing carbon number, with the most abundant being glycine (41 n Moles/g). These and other results to be reviewed provide persuasive support for the theory of chemical evolution and provide the only natural evidence for the protobiological subset of molecules from which life on earth may have arisen.

  18. Oral compound nevus.

    PubMed

    Cardoso, Lyzete Berriel; Consalaro, Alberto; da Silva Santos, Paulo Sérgio; da Silva Sampieri, Marcelo Bonifácio; Tinoco-Araújo, José Endrigo

    2014-02-18

    The melanocytic nevus is a benign and focal proliferation of nevus cells that can be congenital or acquired. Intraoral lesions are uncommon, and the etiology and pathogenesis are poorly understood. The occurrence rate of oral compound nevus is about 5.9% to 16.5% of all oral melanocytic nevi. A 22-year-old male patient presented with a dark brown macule on the buccal mucosa of the maxilla in the region of tooth 26. The lesion was elliptical, 0.7 x 0.5 cm, well circumscribed, asymptomatic, and the evolution time was unknown. An excisional biopsy was performed and microscopic analysis revealed nests of nevus cells in the epithelium and underlying connective tissue that were compatible with melanocytic compound nevus. Owing to the clinical similarity between oral melanocytic nevus and oral melanoma, a histopathological analysis is mandatory for definitive diagnosis.

  19. The Modern Compound Bow.

    PubMed

    Sung, LokMan; Kesha, Kilak; Avedschmidt, Sarah; Root, Kelly; Hlavaty, Leigh

    2017-06-12

    Bows and arrows are ancient weapons that have risen and fallen as the preeminent armaments used by man. Because of the ubiquity of firearms, fatalities from archery injuries in the United States have radically declined. However, when deaths involving this weapon do present themselves, the paucity of reference materials can be a hurdle for forensic pathologists and other forensic scientists. This article will provide a brief history of the origins of the bow and the inception of the compound bow. Comparing and contrasting the structures comprising a traditional bow to those of the modern compound bow will provide insight into how these components function in unison to propel arrows. © 2017 American Academy of Forensic Sciences.

  20. Thermodynamics of Organic Compounds

    DTIC Science & Technology

    1981-01-01

    Organic Compounds by I A. Hossenlopp and D. W. Scott -- Journal of Chemical Thermodynamics , 13, No. 5, 405-414 (1981). t 1 I- i !I *1 I I ~ I [LI...National Bureau of Standards CINDAS Chemical Thermodynamics Division Purdue University Research Park Attn: Dr Stan Abramowitz Attn: Dr H H Li Mr David... Chemical Thermodynamics Division AFAOL/RJT (Dr 7 D Stull) Attn: Mr Donald D Wagman Wright-Patterson AFB, OH 45433 Washington, DC 20234 U.S. Army

  1. Antitumor compounds from tunicates.

    PubMed

    Rinehart, K L

    2000-01-01

    Of the six marine-derived compounds that have reached clinical trials as antitumor agents three-didemnin B, Aplidine, and ecteinascidin 743-are derived from tunicates. Di-demnin B (DB), a cyclic depsipeptide from the compound tunicate Trididemnum solidum, was the first marine-derived compound to enter Phases I and II clinical trials. The Phase II studies, sponsored by the U. S. National Cancer Institute, indicated complete or partial remissions with non-Hodgkins lymphoma, but cardiotoxicity caused didemnin B to be dropped from further study. The closely related dehydrodidemnin B (DDB, Aplidine) was isolated in 1988 from a second colonial tunicate, Aplidium albicans, and spectroscopic studies assigned a structural formula in which a pyruvyl group in DDB replaced the lactyl group in DB and syntheses of DDB have been achieved. Aplidine is more active than DB and lacks DB's cardiotoxicity. It was introduced by PharmaMar into Phase I clinical trials in January 1999. The second family of tunicate-derived antitumor agents are the ecteinascidins (ETs), from the mangrove tunicate Ecteinascidia turbinata. The antitumor extracts of E. turbinata were first described in 1969, but the small amount of ETs in E. turbinata prevented their isolation for over a decade. The structures of ETs have been assigned mainly by spectroscopy. Phase II clinical trials with ET 743 are underway. Future supplies of ET's should be available from aquaculture or synthesis. Copyright 2000 John Wiley & Sons, Inc. Med Res Rev, 20, No. 1, 1-27, 2000

  2. Compound chondrules fused cold

    NASA Astrophysics Data System (ADS)

    Hubbard, Alexander

    2015-07-01

    About 4-5% of chondrules are compound: two separate chondrules stuck together. This is commonly believed to be the result of the two component chondrules having collided shortly after forming, while still molten. This allows high velocity impacts to result in sticking. However, at T ∼ 1100 K, the temperature below which chondrules collide as solids (and hence usually bounce), coalescence times for droplets of appropriate composition are measured in tens of seconds. Even at 1025 K, at which temperature theory predicts that the chondrules must have collided extremely slowly to have stuck together, the coalescence time scale is still less than an hour. These coalescence time scales are too short for the collision of molten chondrules to explain the observed frequency of compound chondrules. We suggest instead a scenario where chondrules stuck together in slow collisions while fully solid; and the resulting chondrule pair was subsequently briefly heated to a temperature in the range of 900-1025 K. In that temperature window the coalescence time is finite but long, covering a span of hours to a decade. This is particularly interesting because those temperatures are precisely the critical window for thermally ionized MRI activity, so compound chondrules provide a possible probe into that vital regime.

  3. Antifungal compounds from cyanobacteria.

    PubMed

    Shishido, Tânia K; Humisto, Anu; Jokela, Jouni; Liu, Liwei; Wahlsten, Matti; Tamrakar, Anisha; Fewer, David P; Permi, Perttu; Andreote, Ana P D; Fiore, Marli F; Sivonen, Kaarina

    2015-04-13

    Cyanobacteria are photosynthetic prokaryotes found in a range of environments. They are infamous for the production of toxins, as well as bioactive compounds, which exhibit anticancer, antimicrobial and protease inhibition activities. Cyanobacteria produce a broad range of antifungals belonging to structural classes, such as peptides, polyketides and alkaloids. Here, we tested cyanobacteria from a wide variety of environments for antifungal activity. The potent antifungal macrolide scytophycin was detected in Anabaena sp. HAN21/1, Anabaena cf. cylindrica PH133, Nostoc sp. HAN11/1 and Scytonema sp. HAN3/2. To our knowledge, this is the first description of Anabaena strains that produce scytophycins. We detected antifungal glycolipopeptide hassallidin production in Anabaena spp. BIR JV1 and HAN7/1 and in Nostoc spp. 6sf Calc and CENA 219. These strains were isolated from brackish and freshwater samples collected in Brazil, the Czech Republic and Finland. In addition, three cyanobacterial strains, Fischerella sp. CENA 298, Scytonema hofmanni PCC 7110 and Nostoc sp. N107.3, produced unidentified antifungal compounds that warrant further characterization. Interestingly, all of the strains shown to produce antifungal compounds in this study belong to Nostocales or Stigonematales cyanobacterial orders.

  4. Toxic compounds in honey.

    PubMed

    Islam, Md Nazmul; Khalil, Md Ibrahim; Islam, Md Asiful; Gan, Siew Hua

    2014-07-01

    There is a wealth of information about the nutritional and medicinal properties of honey. However, honey may contain compounds that may lead to toxicity. A compound not naturally present in honey, named 5-hydroxymethylfurfural (HMF), may be formed during the heating or preservation processes of honey. HMF has gained much interest, as it is commonly detected in honey samples, especially samples that have been stored for a long time. HMF is a compound that may be mutagenic, carcinogenic and cytotoxic. It has also been reported that honey can be contaminated with heavy metals such as lead, arsenic, mercury and cadmium. Honey produced from the nectar of Rhododendron ponticum contains alkaloids that can be poisonous to humans, while honey collected from Andromeda flowers contains grayanotoxins, which can cause paralysis of limbs in humans and eventually leads to death. In addition, Melicope ternata and Coriaria arborea from New Zealand produce toxic honey that can be fatal. There are reports that honey is not safe to be consumed when it is collected from Datura plants (from Mexico and Hungary), belladonna flowers and Hyoscamus niger plants (from Hungary), Serjania lethalis (from Brazil), Gelsemium sempervirens (from the American Southwest), Kalmia latifolia, Tripetalia paniculata and Ledum palustre. Although the symptoms of poisoning due to honey consumption may differ depending on the source of toxins, most common symptoms generally include dizziness, nausea, vomiting, convulsions, headache, palpitations or even death. It has been suggested that honey should not be considered a completely safe food.

  5. Compound cycle engine program

    NASA Technical Reports Server (NTRS)

    Bobula, G. A.; Wintucky, W. T.; Castor, J. G.

    1986-01-01

    The Compound Cycle Engine (CCE) is a highly turbocharged, power compounded power plant which combines the lightweight pressure rise capability of a gas turbine with the high efficiency of a diesel. When optimized for a rotorcraft, the CCE will reduce fuel burned for a typical 2 hr (plus 30 min reserve) mission by 30 to 40 percent when compared to a conventional advanced technology gas turbine. The CCE can provide a 50 percent increase in range-payload product on this mission. A program to establish the technology base for a Compound Cycle Engine is presented. The goal of this program is to research and develop those technologies which are barriers to demonstrating a multicylinder diesel core in the early 1990's. The major activity underway is a three-phased contract with the Garrett Turbine Engine Company to perform: (1) a light helicopter feasibility study, (2) component technology development, and (3) lubricant and material research and development. Other related activities are also presented.

  6. Coexistence of Three Ferroic Orders in the Multiferroic Compound [(CH3 )4 N][Mn(N3 )3 ] with Perovskite-Like Structure.

    PubMed

    Gómez-Aguirre, L Claudia; Pato-Doldán, Breogán; Stroppa, Alessandro; Yang, Li-Ming; Frauenheim, Thomas; Mira, Jorge; Yáñez-Vilar, Susana; Artiaga, Ramón; Castro-García, Socorro; Sánchez-Andújar, Manuel; Señarís-Rodríguez, María Antonia

    2016-06-01

    The perovskite azido compound [(CH3 )4 N][Mn(N3 )3 ], which undergoes a first-order phase change at Tt =310 K with an associated magnetic bistability, was revisited in the search for additional ferroic orders. The driving force for such structural transition is multifold and involves a peculiar cooperative rotation of the [MnN6 ] octahedral as well as order/disorder and off-center shifts of the [(CH3 )4 N](+) cations and bridging azide ligands, which also bend and change their coordination mode. According to DFT calculations the latter two give rise to the appearance of electric dipoles in the low-temperature (LT) polymorph, the polarization of which nevertheless cancels out due to their antiparallel alignment in the crystal. The conversion of this antiferroelectric phase to the paraelectric phase could be responsible for the experimental dielectric anomaly detected at 310 K. Additionally, the structural change involves a ferroelastic phase transition, whereby the LT polymorph exhibits an unusual and anisotropic thermal behavior. Hence, [(CH3 )4 N][Mn(N3 )3 ] is a singular material in which three ferroic orders coexist even above room temperature.

  7. Offset Compound Gear Drive

    NASA Technical Reports Server (NTRS)

    Stevens, Mark A.; Handschuh, Robert F.; Lewicki, David G.

    2010-01-01

    The Offset Compound Gear Drive is an in-line, discrete, two-speed device utilizing a special offset compound gear that has both an internal tooth configuration on the input end and external tooth configuration on the output end, thus allowing it to mesh in series, simultaneously, with both a smaller external tooth input gear and a larger internal tooth output gear. This unique geometry and offset axis permits the compound gear to mesh with the smaller diameter input gear and the larger diameter output gear, both of which are on the same central, or primary, centerline. This configuration results in a compact in-line reduction gear set consisting of fewer gears and bearings than a conventional planetary gear train. Switching between the two output ratios is accomplished through a main control clutch and sprag. Power flow to the above is transmitted through concentric power paths. Low-speed operation is accomplished in two meshes. For the purpose of illustrating the low-speed output operation, the following example pitch diameters are given. A 5.0 pitch diameter (PD) input gear to 7.50 PD (internal tooth) intermediate gear (0.667 reduction mesh), and a 7.50 PD (external tooth) intermediate gear to a 10.00 PD output gear (0.750 reduction mesh). Note that it is not required that the intermediate gears on the offset axis be of the same diameter. For this example, the resultant low-speed ratio is 2:1 (output speed = 0.500; product of stage one 0.667 reduction and stage two 0.750 stage reduction). The design is not restricted to the example pitch diameters, or output ratio. From the output gear, power is transmitted through a hollow drive shaft, which, in turn, drives a sprag during which time the main clutch is disengaged.

  8. Neurotoxicity of organomercurial compounds.

    PubMed

    Sanfeliu, Coral; Sebastià, Jordi; Cristòfol, Rosa; Rodríguez-Farré, Eduard

    2003-01-01

    Mercury is a ubiquitous contaminant, and a range of chemical species is generated by human activity and natural environmental change. Elemental mercury and its inorganic and organic compounds have different toxic properties, but all them are considered hazardous in human exposure. In an equimolecular exposure basis, organomercurials with a short aliphatic chain are the most harmful compounds and they may cause irreversible damage to the nervous system. Methylmercury (CH(3)Hg(+)) is the most studied following the neurotoxic outbreaks identified as Minamata disease and the Iraq poisoning. The first description of the CNS pathology dates from 1954. Since then, the clinical neurology, the neuropathology and the mechanisms of neurotoxicity of organomercurials have been widely studied. The high thiol reactivity of CH(3)Hg(+), as well as all mercury compounds, has been suggested to be the basis of their harmful biological effects. However, there is clear selectivity of CH(3)Hg(+) for specific cell types and brain structures, which is not yet fully understood. The main mechanisms involved are inhibition of protein synthesis, microtubule disruption, increase of intracellular Ca(2+) with disturbance of neurotransmitter function, oxidative stress and triggering of excitotoxicity mechanisms. The effects are more damaging during CNS development, leading to alterations of the structure and functionality of the nervous system. The major source of CH(3)Hg(+) exposure is the consumption of fish and, therefore, its intake is practically unavoidable. The present concern is on the study of the effects of low level exposure to CH(3)Hg(+) on human neurodevelopment, with a view to establishing a safe daily intake. Recommendations are 0.4 micro g/kg body weight/day by the WHO and US FDA and, recently, 0.1 micro g/kg body weight/day by the US EPA. Unfortunately, these levels are easily attained with few meals of fish per week, depending on the source of the fish and its position in the

  9. Superconductivity in plutonium compounds

    NASA Astrophysics Data System (ADS)

    Sarrao, J. L.; Bauer, E. D.; Mitchell, J. N.; Tobash, P. H.; Thompson, J. D.

    2015-07-01

    Although the family of plutonium-based superconductors is relatively small, consisting of four compounds all of which crystallize in the tetragonal HoCoGa5 structure, these materials serve as an important bridge between the known Ce- and U-based heavy fermion superconductors and the high-temperature cuprate superconductors. Further, the partial localization of 5f electrons that characterizes the novel electronic properties of elemental plutonium appears to be central to the relatively high superconducting transition temperatures that are observed in PuCoGa5, PuRhGa5, PuCoIn5, and PuRhIn5.

  10. Immunomodulating compounds in Basidiomycetes

    PubMed Central

    Mizuno, Masashi; Nishitani, Yosuke

    2013-01-01

    Mushrooms are distinguished as important food containing immunomodulating and anticancer agents. These compounds belong mostly to polysaccharides especially β-d-glucans. Among them, β-1,3-glucan with side chain β-1,6-glucose residues have more important roles in immunomodulating and antitumor activities. In this review, we have introduced polysaccharide mainly from Lentinula edodes and Agaricus blazei Murill with immunomodulating and antitumor activities. In addition, the mechanism of activation of immune response and signal cascade are also reviewed. PMID:23704809

  11. Boronated porphyrin compounds

    DOEpatents

    Kahl, Stephen B.; Koo, Myoung-Seo

    1992-01-01

    A compound is described having the structure ##STR1## where R preferably is ##STR2## and most preferably R.sup.3 is a closo-carborane and R.sup.2 is --H, an alkyl or aryl having 1 to about 7 carbon atoms, This invention was made with Government support under NIH Grant No. CA-37961 awarded by the Department of Health and Human Services and under the Associated Universities Inc. Contract No. De-AC02-76CH00016 with the U.S. Department of Energy. The Government has rights in this invention.

  12. Boronated porphyrin compounds

    DOEpatents

    Kahl, S.B.; Koo, M.S.

    1992-09-22

    A compound is described having the structure ##STR1## where R preferably is ##STR2## and most preferably R.sup.3 is a closo-carborane and R.sup.2 is --H, an alkyl or aryl having 1 to about 7 carbon atoms, This invention was made with Government support under NIH Grant No. CA-37961 awarded by the Department of Health and Human Services and under the Associated Universities Inc. Contract No. De-AC02-76CH00016 with the U.S. Department of Energy. The Government has rights in this invention.

  13. Compound Semiconductor Characterization.

    DTIC Science & Technology

    1984-06-08

    Elsevier, New York, 1979). 12. I.R. Sites and 11.11. Wieder, [EEE Trans. Electron Devices, ED-27, 2277 (1980). 13. P.R. Jay and R.H. Wallis, IEEE...Orpington, U. K., 1980). 18. .. Hallais, A. Mircea -Roussel, J.P. Farges, and ;. Poiblaud, in Call im Arsenide and Related Compounds (St. Louis 1976...1979). 78 q 21. P.B. Klei~n, P.IK.R. Nordquist, and P.C. Siebenmann, J. Appl. Phys. 51, 4861 (1980). 22. A. Mircea -Roussel, G. Jacob, and J.P. Hallais

  14. Oligosilanylated Antimony Compounds

    PubMed Central

    2015-01-01

    By reactions of magnesium oligosilanides with SbCl3, a number of oligosilanylated antimony compounds were obtained. When oligosilanyl dianions were used, either the expected cyclic disilylated halostibine was obtained or alternatively the formation of a distibine was observed. Deliberate formation of the distibine from the disilylated halostibine was achieved by reductive coupling with C8K. Computational studies of Sb–Sb bond energies, barriers of pyramidal inversion at Sb, and the conformational behavior of distibines provided insight for the understanding of the spectroscopic properties. PMID:25937691

  15. Titanium alkoxide compound

    DOEpatents

    Boyle, Timothy J.

    2007-08-14

    A titanium alkoxide composition is provided, as represented by the chemical formula (OC.sub.6H.sub.5N).sub.2Ti(OC.sub.6H.sub.5NH.sub.2).sub.2. As prepared, the compound is a crystalline substance with a hexavalent titanium atom bonded to two OC.sub.6H.sub.5NH.sub.2 groups and two OC.sub.6H.sub.5N groups with a theoretical molecular weight of 480.38, comprising 60.01% C, 5.04% H and 11.66% N.

  16. Special Risks of Pharmacy Compounding

    MedlinePlus

    ... Consumer Updates RSS Feed The Special Risks of Pharmacy Compounding Get Consumer Updates by E-mail Consumer ... page: A Troubling Trend What You Can Do Pharmacy compounding is a practice in which a licensed ...

  17. FLUOROCARBON N-F COMPOUNDS

    DTIC Science & Technology

    FLUORIDES, *FLUORINATED HYDROCARBONS, ALKYL RADICALS, CARBOXYLIC ACIDS, CATALYSTS , CESIUM COMPOUNDS, CHEMICAL EQUILIBRIUM, IMIDES, IMINES, MOLECULAR...STRUCTURE, NITRILES, NUCLEAR MAGNETIC RESONANCE, PROPENES, REACTION KINETICS, SUBSTITUTION REACTIONS , SULFUR COMPOUNDS, SYNTHESIS.

  18. Color Classification of Coordination Compounds.

    ERIC Educational Resources Information Center

    Poncini, Laurence; Wimmer, Franz L.

    1987-01-01

    Proposes that colored compounds be classified by reference to a standard color-order system incorporating a color dictionary. Argues that the colors of new compounds could be incorporated into the characterization process and into computer storage systems. (TW)

  19. Color Classification of Coordination Compounds.

    ERIC Educational Resources Information Center

    Poncini, Laurence; Wimmer, Franz L.

    1987-01-01

    Proposes that colored compounds be classified by reference to a standard color-order system incorporating a color dictionary. Argues that the colors of new compounds could be incorporated into the characterization process and into computer storage systems. (TW)

  20. High temperature superconducting compounds

    NASA Astrophysics Data System (ADS)

    Goldman, Allen M.

    1992-11-01

    The major accomplishment of this grant has been to develop techniques for the in situ preparation of high-Tc superconducting films involving the use of ozone-assisted molecular beam epitaxy. The techniques are generalizable to the growth of trilayer and multilayer structures. Films of both the DyBa2Cu3O(7-x) and YBa2Cu3O(7-x) compounds as well as the La(2-x)Sr(x)CuO4 compound have been grown on the usual substrates, SrTiO3, YSZ, MgO, and LaAlO3, as well as on Si substrates without any buffer layer. A bolometer has been fabricated on a thermally isolated SiN substrate coated with YSZ, an effort carried out in collaboration with Honeywell Inc. The deposition process facilitates the fabrication of very thin and transparent films creating new opportunities for the study of superconductor-insulator transitions and the investigation of photo-doping with carriers of high temperature superconductors. In addition to a thin film technology, a patterning technology has been developed. Trilayer structures have been developed for FET devices and tunneling junctions. Other work includes the measurement of the magnetic properties of bulk single crystal high temperature superconductors, and in collaboration with Argonne National Laboratory, measurement of electric transport properties of T1-based high-Tc films.

  1. Potential risks of pharmacy compounding.

    PubMed

    Gudeman, Jennifer; Jozwiakowski, Michael; Chollet, John; Randell, Michael

    2013-03-01

    Pharmacy compounding involves the preparation of customized medications that are not commercially available for individual patients with specialized medical needs. Traditional pharmacy compounding is appropriate when done on a small scale by pharmacists who prepare the medication based on an individual prescription. However, the regulatory oversight of pharmacy compounding is significantly less rigorous than that required for Food and Drug Administration (FDA)-approved drugs; as such, compounded drugs may pose additional risks to patients. FDA-approved drugs are made and tested in accordance with good manufacturing practice regulations (GMPs), which are federal statutes that govern the production and testing of pharmaceutical products. In contrast, compounded drugs are exempt from GMPs, and testing to assess product quality is inconsistent. Unlike FDA-approved drugs, pharmacy-compounded products are not clinically evaluated for safety or efficacy. In addition, compounded preparations do not have standard product labeling or prescribing information with instructions for safe use. Compounding pharmacies are not required to report adverse events to the FDA, which is mandatory for manufacturers of FDA-regulated medications. Some pharmacies engage in activities that extend beyond the boundaries of traditional pharmacy compounding, such as large-scale production of compounded medications without individual patient prescriptions, compounding drugs that have not been approved for use in the US, and creating copies of FDA-approved drugs. Compounding drugs in the absence of GMPs increases the potential for preparation errors. When compounding is performed on a large scale, such errors may adversely affect many patients. Published reports of independent testing by the FDA, state agencies, and others consistently show that compounded drugs fail to meet specifications at a considerably higher rate than FDA-approved drugs. Compounded sterile preparations pose the additional risk

  2. Intracranial compound odontome.

    PubMed

    de Faria, Paulo Rogério; Cardoso, Sérgio Vitorino; Rocha, Ademir; Gomes, Débora Cristiane; de Castro, Samuel Caputo; Loyola, Adriano Mota

    2009-10-01

    An exceedingly rare case of an extragnathic odontome is described arising within the brain. A 10-year-old boy complained of progressive frontal headache for 5 years. Axial computerized tomography the head revealed a solid, calcified lesion with well-defined borders localized in the sellar and suprasellar region composed of multiple calcified structures resembling teeth. The diagnosis was compound odontome. Physical examination and blood analysis revealed hypopituitarism. The patient was submitted for radical tumour resection. He developed persistent diabetes insipidus, hypothyroidism and adrenal insufficiency for which appropriate replacement therapy has been necessary. This case demonstrates that an odontogenic lesion may arise in brain tissues due to the embryological relationship between primordial stomodeum and Rathke's pouch. Its development could be associated with endocrine disturbances.

  3. [Energies of organic compounds

    SciTech Connect

    Wiberg, K.B.

    1991-12-31

    The enthalpy of reduction of lactones to the corresponding diols has been determined, allowing the enthaipies of formation of the lactones to be determined. Results of this study agree well with data obtained for enthalpies of hydrolysis of the lactones. We have begun the measurement of the enthalpies of reduction of norbornanones, and we have shown that it is possible to determine the difference in energy between the exo and endo forms of the product alcohols by measuring the equilibrium constant as a function of temperature. The study of the enthalpies of hydration of carbonyl compounds has continued, and the enthalpies of hydrolysis of the corresponding ketals is being determined. The study of the enthalpies of hydration of alkenes is nearly completed, and the rearrangement reactions which were uncovered are being investigated.

  4. Public chemical compound databases.

    PubMed

    Williams, Anthony J

    2008-05-01

    The internet has rapidly become the first port of call for all information searches. The increasing array of chemistry-related resources that are now available provides chemists with a direct path to the information that was previously accessed via library services and was limited by commercial and costly resources. The diversity of the information that can be accessed online is expanding at a dramatic rate, and the support for publicly available resources offers significant opportunities in terms of the benefits to science and society. While the data online do not generally meet the quality standards of manually curated sources, there are efforts underway to gather scientists together and 'crowdsource' an improvement in the quality of the available data. This review discusses the types of public compound databases that are available online and provides a series of examples. Focus is also given to the benefits and disruptions associated with the increased availability of such data and the integration of technologies to data mine this information.

  5. Compound power plant

    SciTech Connect

    Smith, R.R.

    1991-02-05

    This patent describes a compound motor for a vehicle. It comprises: an engine defining therein a chamber for the combustion of fuel, an intake passage leading to the combustion chamber and an exhaust passage leading from the combustion chamber; a drive shaft extending from the engine; means in the engine for rotating the drive shaft in response to the combustion of fuel in the chamber; a rotary compressor at the entry end of the intake passage; a turbine at the exit end of the exhaust passage, the turbine being drivable by exhaust gases from the combustion chamber; means for selectively transferring rotational motion of the turbine to the compressor, the transferring means including a clutch for mechanically connecting or disconnecting the compressor from the turbine; a planetary gear set having a sun gear member, a ring gear member surrounding the sun gear member, a planet gear member rotatable about its own axis and meshed between the sun gear member and the ring gear member, and a planet carrier member upon which the planet gear member is mounted for revolution about the sun gear member; a gear train between one of the members of the planetary gear set and the turbine; another one of the members of the planetary gear set being driven by the shaft extending from the engine; and a final output shaft driven by a third member of the planetary gear set.

  6. Compounding with Silicones.

    PubMed

    Allen, Loyd V

    2015-01-01

    Since the 1940s, methylchlorosilanes have been used to treat glassware to prevent blood from clotting. The use of silicones in pharmaceutical and medical applications has grown to where today they are used in many life-saving devices (pacemakers, hydrocephalic shunts) and pharmaceutical applications from tubing, to excipients in topical formulations, to adhesives to affix transdermal drug delivery systems, and are also being used in products as active pharmaceutical ingredients, such as antiflatulents. About 60% of today's skin-care products now contain some type of silicone where they are considered safe and are known to provide a pleasant "silky-touch," non-greasy, and non-staining feel. Silicones exhibit many useful characteristics, and the safety of these agents supports their numerous applications; their biocompatibility is partially due to their low-chemical reactivity displayed by silicones, low-surface energy, and their hydrophobicity. Silicones are used both as active ingredients and as excipients. In addition is their use for "siliconization," or surface treatment, of many parenteral packaging components. Dimethicone and silicone oil are used as lubricants on stoppers to aid machineability, in syringes to aid piston movement, or on syringe needles to reduce pain upon injection. Silicones are also useful in pharmaceutical compounding as is discussed in this artiele included with this article are in developing formulations with silicones.

  7. Pluto's Nonvolatile Chemical Compounds

    NASA Astrophysics Data System (ADS)

    Grundy, William M.; Binzel, Richard; Cook, Jason C.; Cruikshank, Dale P.; Dalle Ore, Cristina M.; Earle, Alissa M.; Ennico, Kimberly; Jennings, Donald; Howett, Carly; Kaiser, Ralf-Ingo; Linscott, Ivan; Lunsford, A. W.; Olkin, Catherine B.; Parker, Alex Harrison; Parker, Joel Wm.; Philippe, Sylvain; Protopapa, Silvia; Quirico, Eric; Reuter, D. C.; Schmitt, Bernard; Singer, Kelsi N.; Spencer, John R.; Stansberry, John A.; Stern, S. Alan; Tsang, Constantine; Verbiscer, Anne J.; Weaver, Harold A.; Weigle, G. E.; Young, Leslie

    2016-10-01

    Despite the migration of Pluto's volatile ices (N2, CO, and CH4) around the surface on seasonal timescales, the planet's non-volatile materials are not completely hidden from view. They occur in a variety of provinces formed over a wide range of timescales, including rugged mountains and chasms, the floors of mid-latitude craters, and an equatorial belt of especially dark and reddish material typified by the informally named Cthulhu Regio. NASA's New Horizons probe observed several of these regions at spatial resolutions as fine as 3 km/pixel with its LEISA imaging spectrometer, covering wavelengths from 1.25 to 2.5 microns. Various compounds that are much lighter than the tholin-like macromolecules responsible for the reddish coloration, but that are not volatile at Pluto surface temperatures such as methanol (CH3OH) and ethane (C2H6) have characteristic absorption bands within LEISA's wavelength range. This presentation will describe their geographic distributions and attempt to constrain their origins. Possibilities include an inheritance from Pluto's primordial composition (the likely source of H2O ice seen on Pluto's surface) or ongoing production from volatile precursors through photochemistry in Pluto's atmosphere or through radiolysis on Pluto's surface. New laboratory data inform the analysis.This work was supported by NASA's New Horizons project.

  8. Method of preparing metallocene compounds

    DOEpatents

    Rosenblum, Myron; Matchett, Stephen A.

    1992-01-01

    This invention describes a novel method of preparing metallocene compounds. The invention is based on synthesis of novel bis cyclopentadienides that, under appropriate conditions, will either encapsulate a transition metal to produce a metallocene such as ferrocene, or ferrocene derivative, or will yield a polymeric metallocene. Compounds produced by this process are useful as catalysts in propulsion systems, or as anti-knock compounds in gasolines.

  9. Biomedical Compounds from Marine organisms

    PubMed Central

    Jha, Rajeev Kumar; Zi-rong, Xu

    2004-01-01

    The Ocean, which is called the ‘mother of origin of life’, is also the source of structurally unique natural products that are mainly accumulated in living organisms. Several of these compounds show pharmacological activities and are helpful for the invention and discovery of bioactive compounds, primarily for deadly diseases like cancer, acquired immuno-deficiency syndrome (AIDS), arthritis, etc., while other compounds have been developed as analgesics or to treat inflammation, etc. The life-saving drugs are mainly found abundantly in microorganisms, algae and invertebrates, while they are scarce in vertebrates. Modern technologies have opened vast areas of research for the extraction of biomedical compounds from oceans and seas.

  10. Organic Compounds in Carbonaceous Meteorites

    NASA Technical Reports Server (NTRS)

    Cooper, Grorge

    2001-01-01

    Carbonaceous meteorites are relatively enriched in soluble organic compounds. To date, these compounds provide the only record available to study a range of organic chemical processes in the early Solar System chemistry. The Murchison meteorite is the best-characterized carbonaceous meteorite with respect to organic chemistry. The study of its organic compounds has related principally to aqueous meteorite parent body chemistry and compounds of potential importance for the origin of life. Among the classes of organic compounds found in Murchison are amino acids, amides, carboxylic acids, hydroxy acids, sulfonic acids, phosphonic acids, purines and pyrimidines (Table 1). Compounds such as these were quite likely delivered to the early Earth in asteroids and comets. Until now, polyhydroxylated compounds (polyols), including sugars (polyhydroxy aldehydes or ketones), sugar alcohols, sugar acids, etc., had not been identified in Murchison. Ribose and deoxyribose, five-carbon sugars, are central to the role of contemporary nucleic acids, DNA and RNA. Glycerol, a three-carbon sugar alcohol, is a constituent of all known biological membranes. Due to the relative lability of sugars, some researchers have questioned the lifetime of sugars under the presumed conditions on the early Earth and postulated other (more stable) compounds as constituents of the first replicating molecules. The identification of potential sources and/or formation mechanisms of pre-biotic polyols would add to the understanding of what organic compounds were available, and for what length of time, on the ancient Earth.

  11. Transition Metal Compounds Towards Holography

    PubMed Central

    Dieckmann, Volker; Eicke, Sebastian; Springfeld, Kristin; Imlau, Mirco

    2012-01-01

    We have successfully proposed the application of transition metal compounds in holographic recording media. Such compounds feature an ultra-fast light-induced linkage isomerization of the transition-metal–ligand bond with switching times in the sub-picosecond regime and lifetimes from microseconds up to hours at room temperature. This article highlights the photofunctionality of two of the most promising transition metal compounds and the photophysical mechanisms that are underlying the hologram recording. We present the latest progress with respect to the key measures of holographic media assembled from transition metal compounds, the molecular embedding in a dielectric matrix and their impressive potential for modern holographic applications. PMID:28817028

  12. Saturn's Stratospheric Oxygen Compounds

    NASA Astrophysics Data System (ADS)

    Romani, Paul N.; Delgado Díaz, Héctor E.; Bjoraker, Gordon; Hesman, Brigette; Achterberg, Richard

    2016-10-01

    There are three known oxygenated species present in Saturn's upper atmosphere: H2O, CO and CO2. The ultimate source of the water must be external to Saturn as Saturn's cold tropopause effectively prevents any internal water from reaching the upper atmosphere. The carbon monoxide and dioxide source(s) could be internal, external, produced by the photochemical interaction of water with Saturn's stratospheric hydrocarbons or some combination of all of these. At this point it is not clear what the external source(s) are.Cassini's Composite InfraRed Spectrometer (CIRS) has detected emission lines of H2O and CO2 (Hesman et al., DPS 2015, 311.16 & Abbas et al. 2013, Ap. J. doi:10.1088/0004-637X/776/2/73) on Saturn. CIRS also retrieves the temperature of the stratosphere using CH4 lines at 7.7 microns. Using CIRS retrieved temperatures, the mole fraction of H2O at the 0.5-5 mbar level can be retrieved and the CO2 mole fraction at ~1-10 mbar. Coupled with ground based observations of CO (Cavalié et al., 2010, A&A, DOI: 10.1051/0004-6361/200912909) these observations provide a complete oxygen compound data set to test photochemical models.Preliminary results will be presented with an emphasis on upper limit analysis to determine the percentage of stratospheric CO and CO2 that can be produced photochemically from CIRS observational constraints on the H2O profile.

  13. Antimicrobial compounds in tears.

    PubMed

    McDermott, Alison M

    2013-12-01

    The tear film coats the cornea and conjunctiva and serves several important functions. It provides lubrication, prevents drying of the ocular surface epithelia, helps provide a smooth surface for refracting light, supplies oxygen and is an important component of the innate defense system of the eye providing protection against a range of potential pathogens. This review describes both classic antimicrobial compounds found in tears such as lysozyme and some more recently identified such as members of the cationic antimicrobial peptide family and surfactant protein-D as well as potential new candidate molecules that may contribute to antimicrobial protection. As is readily evident from the literature review herein, tears, like all mucosal fluids, contain a plethora of molecules with known antimicrobial effects. That all of these are active in vivo is debatable as many are present in low concentrations, may be influenced by other tear components such as the ionic environment, and antimicrobial action may be only one of several activities ascribed to the molecule. However, there are many studies showing synergistic/additive interactions between several of the tear antimicrobials and it is highly likely that cooperativity between molecules is the primary way tears are able to afford significant antimicrobial protection to the ocular surface in vivo. In addition to effects on pathogen growth and survival some tear components prevent epithelial cell invasion and promote the epithelial expression of innate defense molecules. Given the protective role of tears a number of scenarios can be envisaged that may affect the amount and/or activity of tear antimicrobials and hence compromise tear immunity. Two such situations, dry eye disease and contact lens wear, are discussed here. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Antimicrobial Compounds in Tears

    PubMed Central

    McDermott, Alison M.

    2013-01-01

    The tear film coats the cornea and conjunctiva and serves several important functions. It provides lubrication, prevents drying of the ocular surface epithelia, helps provide a smooth surface for refracting light, supplies oxygen and is an important component of the innate defense system of the eye providing protection against a range of potential pathogens. This review describes both classic antimicrobial compounds found in tears such as lysozyme and some more recently identified such as members of the cationic antimicrobial peptide family and surfactant protein-D as well as potential new candidate molecules that may contribute to antimicrobial protection. As is readily evident from the literature review herein, tears, like all mucosal fluids, contain a plethora of molecules with known antimicrobial effects. That all of these are active in vivo is debatable as many are present in low concentrations, may be influenced by other tear components such as the ionic environment, and antimicrobial action may be only one of several activities ascribed to the molecule. However, there are many studies showing synergistic/additive interactions between several of the tear antimicrobials and it is highly likely that cooperativity between molecules is the primary way tears are able to afford significant antimicrobial protection to the ocular surface in vivo. In addition to effects on pathogen growth and survival some tear components prevent epithelial cell invasion and promote the epithelial expression of innate defense molecules. Given the protective role of tears a number of scenarios can be envisaged that may affect the amount and/or activity of tear antimicrobials and hence compromise tear immunity. Two such situations, dry eye disease and contact lens wear, are discussed here. PMID:23880529

  15. Ruminal methane inhibition potential of various pure compounds in comparison with garlic oil as determined with a rumen simulation technique (Rusitec).

    PubMed

    Soliva, Carla R; Amelchanka, Sergej L; Duval, Stéphane M; Kreuzer, Michael

    2011-07-01

    Ruminants represent an important source of methane (CH(4)) emissions; therefore, CH(4) mitigation by diet supplementation is a major goal in the current ruminant research. The objective of the present study was to use a rumen simulation technique to evaluate the CH(4)-mitigating potential of pure compounds in comparison with that achieved with garlic oil, a known anti-methanogenic supplement. A basal diet (15 g DM/d) consisting of ryegrass hay, barley and soyabean meal (1:0·7:0·3) was incubated with the following additives: none (negative control); garlic oil (300 mg/l incubation liquid; positive control); allyl isothiocyanate (75 mg/l); lovastatin (150 mg/l); chenodeoxycholic acid (150 mg/l); 3-azido-propionic acid ethyl ester (APEE, 150 mg/l); levulinic acid (300 mg/l); 4-[(pyridin-2-ylmethyl)-amino]-benzoic acid (PABA, 300 mg/l). Fermentation profiles (SCFA, microbial counts and N turnover) and H(2) and CH(4) formation were determined. Garlic oil, allyl isothiocyanate, lovastatin and the synthetic compound APEE decreased the absolute daily CH(4) formation by 91, 59, 42 and 98 %, respectively. The corresponding declines in CH(4) emitted per mmol of SCFA were 87, 32, 40 and 99 %, respectively, compared with the negative control; the total SCFA concentration was unaffected. Garlic oil decreased protozoal numbers and increased bacterial counts, while chenodeoxycholic acid completely defaunated the incubation liquid. In vitro, neutral-detergent fibre disappearance was lower following chenodeoxycholic acid and PABA treatments (- 26 and - 18 %, respectively). In conclusion, garlic oil and APEE were extremely efficient at mitigating CH(4) without noticeably impairing microbial nutrient fermentation. Other promising substances were allyl isothiocyanate and lovastatin.

  16. Antifungal Compounds from Piper Species

    PubMed Central

    Xu, Wen-Hui; Li, Xing-Cong

    2013-01-01

    This review documents chemical structures and antifungal activities of 68 compounds isolated from 22 Piper species of the plant family Piperaceae. These compounds include amides, flavonoids, prenylated benzoic acid derivatives, lignans, phenylpropanoids, butenolides, and cyclopentendiones. Some of them may serve as leads for potential pharmaceutical or agricultural fungicide development. PMID:24307889

  17. Morphological Dynamics in Compound Processing

    ERIC Educational Resources Information Center

    Kuperman, Victor; Bertram, Raymond; Baayen, R. Harald

    2008-01-01

    This paper explores the time-course of morphological processing of trimorphemic Finnish compounds. We find evidence for the parallel access to full-forms and morphological constituents diagnosed by the early effects of compound frequency, as well as early effects of left constituent frequency and family size. We also observe an interaction between…

  18. METHOD OF REDUCING PLUTONIUM COMPOUNDS

    DOEpatents

    Johns, I.B.

    1958-06-01

    A method is described for reducing plutonium compounds in aqueous solution from a higher to a lower valence state. This reduction of valence is achieved by treating the aqueous solution of higher valence plutonium compounds with hydrogen in contact with an activated platinum catalyst.

  19. Testing of Experimental Antileishmanial Compounds.

    DTIC Science & Technology

    1994-10-19

    administrative and clerical assistance and Ms. Barbara L. Harris, Laboratory Technician II, for technical assistance with this study. Their efforts are appreciated...braziliensis) leishmaniasis . Although several new compounds have been identified with activity against L. (V.) braziliensis, none have shown adequate promise...to warrant initiation of clinical trials. However, among the most promising active compounds found against visceral leishmaniasis during these

  20. Bilingual Reading of Compound Words

    ERIC Educational Resources Information Center

    Ko, In Yeong; Wang, Min; Kim, Say Young

    2011-01-01

    The present study investigated whether bilingual readers activate constituents of compound words in one language while processing compound words in the other language via decomposition. Two experiments using a lexical decision task were conducted with adult Korean-English bilingual readers. In Experiment 1, the lexical decision of real English…

  1. Bilingual Reading of Compound Words

    ERIC Educational Resources Information Center

    Ko, In Yeong; Wang, Min; Kim, Say Young

    2011-01-01

    The present study investigated whether bilingual readers activate constituents of compound words in one language while processing compound words in the other language via decomposition. Two experiments using a lexical decision task were conducted with adult Korean-English bilingual readers. In Experiment 1, the lexical decision of real English…

  2. Devices for collecting chemical compounds

    DOEpatents

    Scott, Jill R; Groenewold, Gary S

    2013-12-24

    A device for sampling chemical compounds from fixed surfaces and related methods are disclosed. The device may include a vacuum source, a chamber and a sorbent material. The device may utilize vacuum extraction to volatilize the chemical compounds from a fixed surface so that they may be sorbed by the sorbent material. The sorbent material may then be analyzed using conventional thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS) instrumentation to determine presence of the chemical compounds. The methods may include detecting release and presence of one or more chemical compounds and determining the efficacy of decontamination. The device may be useful in collection and analysis of a variety of chemical compounds, such as residual chemical warfare agents, chemical attribution signatures and toxic industrial chemicals.

  3. Novel bioactive compounds from actinomycetes.

    PubMed

    Sanglier, J J; Wellington, E M; Behal, V; Fiedler, H P; Ellouz Ghorbel, R; Finance, C; Hacene, M; Kamoun, A; Kelly, C; Mercer, D K

    1993-10-01

    Actinomycetes form an enormous reservoir of secondary metabolites and enzymes. The potential for exploiting rare actinomycetes is highlighted by the discovery of novel compounds from strains of Spirillospora and Nocardioides. Novel compounds of well known classes of antibiotics, such as polyenes, continue to be discovered. For compounds containing a chromophore, the analysis by high-performance liquid chromatography coupled with a diode-array detector enables the elimination of producers of known compounds and facilitates the discovery of novel compounds or derivatives. The complexity of the regulatory mechanisms is illustrated by glutamine synthetase. The characterization of thermostable amylolytic, lignolytic, peroxidase and neuramidase activities, and the isolation of novel cellulolytic actinomycetes clearly demonstrate the potential of Actinomycetes as producers of enzymes.

  4. Assimilation of Unusual Carbon Compounds

    NASA Astrophysics Data System (ADS)

    Middelhoven, Wouter J.

    Yeast taxa traditionally are distinguished by growth tests on several sugars and organic acids. During the last decades it became apparent that many yeast species assimilate a much greater variety of naturally occurring carbon compounds as sole source of carbon and energy. These abilities are indicative of a greater role of yeasts in the carbon cycle than previously assumed. Especially in acidic soils and other habitats, yeasts may play a role in the degradation of carbon compounds. Such compounds include purines like uric acid and adenine, aliphatic amines, diamines and hydroxyamines, phenolics and other benzene compounds and polysaccharides. Assimilation of purines and amines is a feature of many ascomycetes and basidiomycetes. However, benzene compounds are degraded by only a few ascomycetous yeasts (e.g. the Stephanoascus/ Blastobotrys clade and black yeastlike fungi) but by many basidiomycetes, e.g. Filobasidiales, Trichosporonales, red yeasts producing ballistoconidia and related species, but not by Tremellales. Assimilation of polysaccharides is wide-spread among basidiomycetes

  5. Complex chemistry with complex compounds

    NASA Astrophysics Data System (ADS)

    Eichler, Robert; Asai, M.; Brand, H.; Chiera, N. M.; Di Nitto, A.; Dressler, R.; Düllmann, Ch. E.; Even, J.; Fangli, F.; Goetz, M.; Haba, H.; Hartmann, W.; Jäger, E.; Kaji, D.; Kanaya, J.; Kaneya, Y.; Khuyagbaatar, J.; Kindler, B.; Komori, Y.; Kraus, B.; Kratz, J. V.; Krier, J.; Kudou, Y.; Kurz, N.; Miyashita, S.; Morimoto, K.; Morita, K.; Murakami, M.; Nagame, Y.; Ooe, K.; Piguet, D.; Sato, N.; Sato, T. K.; Steiner, J.; Steinegger, P.; Sumita, T.; Takeyama, M.; Tanaka, K.; Tomitsuka, T.; Toyoshima, A.; Tsukada, K.; Türler, A.; Usoltsev, I.; Wakabayashi, Y.; Wang, Y.; Wiehl, N.; Wittwer, Y.; Yakushev, A.; Yamaki, S.; Yano, S.; Yamaki, S.; Qin, Z.

    2016-12-01

    In recent years gas-phase chemical studies assisted by physical pre-separation allowed for the investigation of fragile single molecular species by gas-phase chromatography. The latest success with the heaviest group 6 transactinide seaborgium is highlighted. The formation of a very volatile hexacarbonyl compound Sg(CO)6 was observed similarly to its lighter homologues molybdenum and tungsten. The interactions of these gaseous carbonyl complex compounds with quartz surfaces were investigated by thermochromatography. Second-generation experiments are under way to investigate the intramolecular bond between the central metal atom of the complexes and the ligands addressing the influence of relativistic effects in the heaviest compounds. Our contribution comprises some aspects of the ongoing challenging experiments as well as an outlook towards other interesting compounds related to volatile complex compounds in the gas phase.

  6. Bismuth compounds in medicinal chemistry.

    PubMed

    Salvador, Jorge A R; Figueiredo, Sandra A C; Pinto, Rui M A; Silvestre, Samuel M

    2012-07-01

    In recent years, the chemical potential of bismuth and bismuth compounds has been actively exploited. Bismuth salts are known for their low toxicity, making them potential valuable reagents for large-scale synthesis, which becomes more obvious when dealing with products such as active pharmaceutical ingredients or synthetic intermediates. Conversely, bismuth compounds have been widely used in medicine. After extensive use in the treatments of syphilis and other bacterial infections before the advent of modern antibiotics, bismuth compounds remain important for the treatment of several gastrointestinal disorders and also exhibit antimicrobial properties and cytotoxic activity, among others. This review updates relevant advances in the past few years, concerning the application of bismuth reagents and catalysts in innovative synthetic processes for the preparation of compounds of medicinal interest, as well as the preparation, biological evaluation and potential medicinal uses of bismuth compounds.

  7. Current Research on Antiepileptic Compounds.

    PubMed

    Wei, Cheng-Xi; Bian, Ming; Gong, Guo-Hua

    2015-11-20

    Epilepsy affects about 1% of the world's population. Due to the fact all antiepileptic drugs (AEDs) have some undesirable side effects and about 30% of epileptic patients are not seizure-free with the existing AEDs, there is still an urgent need for the development of more effective and safer AEDs. Based on our research work on antiepileptic compounds and other references in recent years, this review covers the reported work on antiepileptic compounds which are classified according to their structures. This review summarized 244 significant anticonvulsant compounds which are classified by functional groups according to the animal model data, although there are some limitations in the data. This review highlights the properties of new compounds endowed with promising antiepileptic properties, which may be proven to be more effective and selective, and possibly free of unwanted side effects. The reviewed compounds represent an interesting possibility to overcome refractory seizures and to reduce the percentage of patients with a poor response to drug therapy.

  8. N-(2-Acetamido-2-de­oxy-β-d-gluco­pyranos­yl)-N-(3-azido­prop­yl)-O-methyl­hydroxyl­amine

    PubMed Central

    Munneke, Stefan; Stocker, Bridget L.; Timmer, Mattie S. M.; Gainsford, Graeme J.

    2016-01-01

    The structure of the title compound, C12H23N5O6, solved using adequate data from a thin crystal plate, confirmed that this useful glycoconjugate was obtained in the ring-closed β-pyran­ose configuration with 4 C 1 conformation. The mol­ecules are bound by O—H⋯O(OH) hydrogen bonds, notably in a zigzag C(2) chain along the short b (screw) axis, supplemented with an R 2 2(12) O—H⋯O(carbon­yl) link along the a axis and other C(2) links. The absolute configuration was not unambiguously determined but was known from the synthetic chemistry, which used natural 2-acetamido-2-de­oxy-d-glucose as the starting material. PMID:27006803

  9. The mononuclear nickel(II) complex bis(azido-κN)bis[2,5-bis(pyridin-2-yl)-1,3,4-thiadiazole-κ(2) N(2) ,N(3) ]nickel(II) protects tomato from Verticillium dahliae by inhibiting fungal growth and activating plant defences.

    PubMed

    Zine, Hanane; Rifai, Lalla Aicha; Koussa, Tayeb; Bentiss, Fouad; Guesmi, Salaheddine; Laachir, Abdelhakim; Makroum, Kacem; Belfaiza, Malika; Faize, Mohamed

    2017-01-01

    The antifungal properties of the nickel(II) complex bis(azido-κN)bis[2,5-bis(pyridin-2-yl)-1,3,4-thiadiazole-κ(2) N(2) ,N(3) ]nickel(II) [NiL2 (N3 )2 ] and its parental ligand 2,5-bis(pyridin-2-yl)-1,3,4-thiadiazole were examined to evaluate their ability to protect tomato plants against Verticillium dahliae. Our main objectives were to determine their effects on the in vitro growth of the pathogen, and their aptitude for controlling verticillium wilt and activating plant defence responses in the greenhouse. NiL2 (N3 )2 exhibited in vitro an elevated inhibition of radial growth of three strains of the pathogen. According to the strain, the EC50 values ranged from 10 to 29 µg mL(-1) for NiL2 (N3 )2 . In the greenhouse, it induced an elevated protection against V. dahliae when it was applied twice as foliar sprays at 50 µg mL(-1) . It reduced the leaf alteration index by 85% and vessel browning by 96%. In addition, its protective ability was associated with the accumulation of H2 O2 and the activation of total phenolic content, as well as potentiation of the activity of peroxidase and polyphenol oxidase. These results demonstrated that the coordination of the ligand with Ni associated with the azide as a coligand resulted in an improvement in its biological activity by both inhibiting the growth of V. dahliae and activating plant defence responses. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  10. Membrane rejection of nitrogen compounds

    NASA Technical Reports Server (NTRS)

    Lee, S.; Lueptow, R. M.

    2001-01-01

    Rejection characteristics of nitrogen compounds were examined for reverse osmosis, nanofiltration, and low-pressure reverse osmosis membranes. The rejection of nitrogen compounds is explained by integrating experimental results with calculations using the extended Nernst-Planck model coupled with a steric hindrance model. The molecular weight and chemical structure of nitrogen compounds appear to be less important in determining rejection than electrostatic properties. The rejection is greatest when the Donnan potential exceeds 0.05 V or when the ratio of the solute radius to the pore radius is greater than 0.8. The transport of solute in the pore is dominated by diffusion, although convective transport is significant for organic nitrogen compounds. Electromigration contributes negligibly to the overall solute transport in the membrane. Urea, a small organic compound, has lower rejection than ionic compounds such as ammonium, nitrate, and nitrite, indicating the critical role of electrostatic interaction in rejection. This suggests that better treatment efficiency for organic nitrogen compounds can be obtained after ammonification of urea.

  11. Membrane rejection of nitrogen compounds

    NASA Technical Reports Server (NTRS)

    Lee, S.; Lueptow, R. M.

    2001-01-01

    Rejection characteristics of nitrogen compounds were examined for reverse osmosis, nanofiltration, and low-pressure reverse osmosis membranes. The rejection of nitrogen compounds is explained by integrating experimental results with calculations using the extended Nernst-Planck model coupled with a steric hindrance model. The molecular weight and chemical structure of nitrogen compounds appear to be less important in determining rejection than electrostatic properties. The rejection is greatest when the Donnan potential exceeds 0.05 V or when the ratio of the solute radius to the pore radius is greater than 0.8. The transport of solute in the pore is dominated by diffusion, although convective transport is significant for organic nitrogen compounds. Electromigration contributes negligibly to the overall solute transport in the membrane. Urea, a small organic compound, has lower rejection than ionic compounds such as ammonium, nitrate, and nitrite, indicating the critical role of electrostatic interaction in rejection. This suggests that better treatment efficiency for organic nitrogen compounds can be obtained after ammonification of urea.

  12. Photoprotective compounds from marine organisms.

    PubMed

    Rastogi, Rajesh P; Richa; Sinha, Rajeshwar P; Singh, Shailendra P; Häder, Donat-P

    2010-06-01

    The substantial loss in the stratospheric ozone layer and consequent increase in solar ultraviolet radiation on the earth's surface have augmented the interest in searching for natural photoprotective compounds in organisms of marine as well as freshwater ecosystems. A number of photoprotective compounds such as mycosporine-like amino acids (MAAs), scytonemin, carotenoids and several other UV-absorbing substances of unknown chemical structure have been identified from different organisms. MAAs form the most common class of UV-absorbing compounds known to occur widely in various marine organisms; however, several compounds having UV-screening properties still need to be identified. The synthesis of scytonemin, a predominant UV-A-photoprotective pigment, is exclusively reported in cyanobacteria. Carotenoids are important components of the photosynthetic apparatus that serve both light-harvesting and photoprotective functions, either by direct quenching of the singlet oxygen or other toxic reactive oxygen species or by dissipating the excess energy in the photosynthetic apparatus. The production of photoprotective compounds is affected by several environmental factors such as different wavelengths of UVR, desiccation, nutrients, salt concentration, light as well as dark period, and still there is controversy about the biosynthesis of various photoprotective compounds. Recent studies have focused on marine organisms as a source of natural bioactive molecules having a photoprotective role, their biosynthesis and commercial application. However, there is a need for extensive work to explore the photoprotective role of various UV-absorbing compounds from marine habitats so that a range of biotechnological and pharmaceutical applications can be found.

  13. Compound curvature laser window development

    NASA Technical Reports Server (NTRS)

    Verhoff, Vincent G.

    1993-01-01

    The NASA Lewis Research Center has developed and implemented a unique process for forming flawless compound curvature laser windows. These windows represent a major part of specialized, nonintrusive laser data acquisition systems used in a variety of compressor and turbine research test facilities. This report summarizes the main aspects of compound curvature laser window development. It is an overview of the methodology and the peculiarities associated with the formulation of these windows. Included in this discussion is new information regarding procedures for compound curvature laser window development.

  14. Polishing compound for plastic surfaces

    SciTech Connect

    Stowell, Michael S.

    1995-01-01

    A polishing compound for plastic surfaces. The compound contains by weight approximately 4 to 17 parts at least one petroleum distillate lubricant, 1 to 6 parts mineral spirits, 2.5 to 15 parts abrasive particles, and 2.5 to 10 parts water. The abrasive is tripoli or a similar material that contains fine particles silica. Preferably, most of the abrasive particles are less than approximately 10 microns, more preferably less than approximately 5 microns in size. The compound is used on PLEXIGLAS.TM., LEXAN.TM., LUCITE.TM., polyvinyl chloride (PVC) and similar plastic materials whenever a smooth, clear polished surface is desired.

  15. Polishing compound for plastic surfaces

    DOEpatents

    Stowell, M.S.

    1993-01-01

    A polishing compound for plastic surfaces is disclosed. The compound contains by weight approximately 4 to 17 parts at least one petroleum distillate lubricant, 1 to 6 parts mineral spirits, 2.5 to 15 parts abrasive particles, and 2.5 to 10 parts water. The abrasive is tripoli or a similar material that contains colloidal silica. Preferably, most of the abrasive particles are less than approximately 10 microns, more preferably less than approximately 5 microns in size. The compound is used on PLEXIGLAS{sup TM}, LEXAN{sup TM}, LUCITE{sup TM}, polyvinyl chloride (PVC) and similar plastic materials whenever a smooth, clear polished surface is desired.

  16. Polishing compound for plastic surfaces

    DOEpatents

    Stowell, M.S.

    1995-08-22

    A polishing compound for plastic surfaces is disclosed. The compound contains by weight approximately 4 to 17 parts at least one petroleum distillate lubricant, 1 to 6 parts mineral spirits, 2.5 to 15 parts abrasive particles, and 2.5 to 10 parts water. The abrasive is tripoli or a similar material that contains fine particles silica. Preferably, most of the abrasive particles are less than approximately 10 microns, more preferably less than approximately 5 microns in size. The compound is used on PLEXIGLAS{trademark}, LEXAN{trademark}, LUCITE{trademark}, polyvinyl chloride (PVC) and similar plastic materials whenever a smooth, clear polished surface is desired. 5 figs.

  17. MEASUREMENT OF INFRARED SPECTRA AND CHEMICAL BONDING OF INORGANIC COMPOUNDS.

    DTIC Science & Technology

    CHROMATES, SELENIUM COMPOUNDS, PERMANGANATES, FLUOBORATES , LITHIUM FLUORIDES, BELGIUM...CRYSTAL STRUCTURE, SODIUM CHLORIDE, LITHIUM COMPOUNDS, BARIUM COMPOUNDS, ALKALINE EARTH COMPOUNDS, ALKALI METAL COMPOUNDS, SULFATES, PERCHLORATES

  18. Crystal structure of bis-(azido-κN)bis[2,5-bis(pyridin-2-yl)-1,3,4-thia-diazole-κ(2) N (2),N (3)]cobalt(II).

    PubMed

    Laachir, Abdelhakim; Bentiss, Fouad; Guesmi, Salaheddine; Saadi, Mohamed; El Ammari, Lahcen

    2015-05-01

    In the mononuclear title complex, [Co(N3)2(C12H8N4S)2], the cobalt(II) atom is located on an inversion centre and displays an axially weakly compressed octa-hedral coordination geometry. The equatorial positions are occupied by the N atoms of two 2,5-bis-(pyridin-2-yl)-1,3,4-thia-diazole ligands, whereas the axial positions are occupied by N atoms of the azide anions. The thia-diazole and pyridine rings linked to the metal are almost coplanar, with a maximum deviation from the mean plane of 0.0273 (16) Å. The cohesion of the crystal is ensured by weak C-H⋯N hydrogen bonds and by π-π inter-actions between pyridine rings [inter-centroid distance = 3.6356 (11) Å], forming a layered arrangement parallel to (001). The structure of the title compound is isotypic with that of the analogous nickel(II) complex [Laachir et al. (2013 ▶). Acta Cryst. E69, m351-m352].

  19. Crystal structure of bis­(azido-κN)bis[2,5-bis(pyridin-2-yl)-1,3,4-thia­diazole-κ2 N 2,N 3]cobalt(II)

    PubMed Central

    Laachir, Abdelhakim; Bentiss, Fouad; Guesmi, Salaheddine; Saadi, Mohamed; El Ammari, Lahcen

    2015-01-01

    In the mononuclear title complex, [Co(N3)2(C12H8N4S)2], the cobalt(II) atom is located on an inversion centre and displays an axially weakly compressed octa­hedral coordination geometry. The equatorial positions are occupied by the N atoms of two 2,5-bis­(pyridin-2-yl)-1,3,4-thia­diazole ligands, whereas the axial positions are occupied by N atoms of the azide anions. The thia­diazole and pyridine rings linked to the metal are almost coplanar, with a maximum deviation from the mean plane of 0.0273 (16) Å. The cohesion of the crystal is ensured by weak C—H⋯N hydrogen bonds and by π–π inter­actions between pyridine rings [inter­centroid distance = 3.6356 (11) Å], forming a layered arrangement parallel to (001). The structure of the title compound is isotypic with that of the analogous nickel(II) complex [Laachir et al. (2013 ▸). Acta Cryst. E69, m351–m352]. PMID:25995853

  20. Compound cueing in free recall

    PubMed Central

    Lohnas, Lynn J.; Kahana, Michael J.

    2013-01-01

    According to the retrieved context theory of episodic memory, the cue for recall of an item is a weighted sum of recently activated cognitive states, including previously recalled and studied items as well as their associations. We show that this theory predicts there should be compound cueing in free recall. Specifically, the temporal contiguity effect should be greater when the two most recently recalled items were studied in contiguous list positions. A meta-analysis of published free recall experiments demonstrates evidence for compound cueing in both conditional response probabilities and inter-response times. To help rule out a rehearsal-based account of these compound cueing effects, we conducted an experiment with immediate, delayed and continual-distractor free recall conditions. Consistent with retrieved context theory but not with a rehearsal-based account, compound cueing was present in all conditions, and was not significantly influenced by the presence of interitem distractors. PMID:23957364

  1. Phenolic compounds in Brassica vegetables.

    PubMed

    Cartea, María Elena; Francisco, Marta; Soengas, Pilar; Velasco, Pablo

    2010-12-30

    Phenolic compounds are a large group of phytochemicals widespread in the plant kingdom. Depending on their structure they can be classified into simple phenols, phenolic acids, hydroxycinnamic acid derivatives and flavonoids. Phenolic compounds have received considerable attention for being potentially protective factors against cancer and heart diseases, in part because of their potent antioxidative properties and their ubiquity in a wide range of commonly consumed foods of plant origin. The Brassicaceae family includes a wide range of horticultural crops, some of them with economic significance and extensively used in the diet throughout the world. The phenolic composition of Brassica vegetables has been recently investigated and, nowadays, the profile of different Brassica species is well established. Here, we review the significance of phenolic compounds as a source of beneficial compounds for human health and the influence of environmental conditions and processing mechanisms on the phenolic composition of Brassica vegetables.

  2. Detection of chlorinated aromatic compounds

    DOEpatents

    Ekechukwu, Amy A.

    1996-01-01

    A method for making a composition for measuring the concentration of chloated aromatic compounds in aqueous fluids, and an optical probe for use with the method. The composition comprises a hydrophobic polymer matrix, preferably polyamide, with a fluorescent indicator uniformly dispersed therein. The indicator fluoresces in the presence of the chlorinated aromatic compounds with an intensity dependent on the concentration of these compounds in the fluid of interest, such as 8-amino-2-naphthalene sulfonate. The probe includes a hollow cylindrical housing that contains the composition in its distal end. The probe admits an aqueous fluid to the probe interior for exposure to the composition. An optical fiber transmits excitation light from a remote source to the composition while the indicator reacts with chlorinated aromatic compounds present in the fluid. The resulting fluorescence light signal is reflected to a second optical fiber that transmits the light to a spectrophotometer for analysis.

  3. Detection of chlorinated aromatic compounds

    DOEpatents

    Ekechukwu, A.A.

    1996-02-06

    A method for making a composition for measuring the concentration of chlorinated aromatic compounds in aqueous fluids, and an optical probe for use with the method are disclosed. The composition comprises a hydrophobic polymer matrix, preferably polyamide, with a fluorescent indicator uniformly dispersed therein. The indicator fluoresces in the presence of the chlorinated aromatic compounds with an intensity dependent on the concentration of these compounds in the fluid of interest, such as 8-amino-2-naphthalene sulfonate. The probe includes a hollow cylindrical housing that contains the composition in its distal end. The probe admits an aqueous fluid to the probe interior for exposure to the composition. An optical fiber transmits excitation light from a remote source to the composition while the indicator reacts with chlorinated aromatic compounds present in the fluid. The resulting fluorescence light signal is reflected to a second optical fiber that transmits the light to a spectrophotometer for analysis. 5 figs.

  4. Crystallographic properties of fertilizer compounds

    SciTech Connect

    Frazier, A.W.; Dillard, E.F.; Thrasher, R.D.; Waerstad, K.R.; Hunter, S.R.; Kohler, J.J.; Scheib, R.M.

    1991-02-01

    This bulletin is a compilation of crystallographic data collected at NFERC on 450 fertilizer-related compounds. In TVA's fertilizer R and D program, petrographic examination, XRD, and infrared spectroscopy are combined with conventional chemical analysis methods in identifying the individual compounds that occur in fertilizer materials. This handbook brings together the results of these characterization studies and supplemental crystallographic data from the literature. It is in one-compound-per-page, loose-leaf format, ordered alphabetically by IUPAC name. Indexes provided include IUPAC name, formula, group, alternate formula, synonyms, x-ray data, optical data. Tables are given for solids, compounds in commercial MAP and DAP, and matrix materials in phosphate rock.

  5. Crystallographic properties of fertilizer compounds

    SciTech Connect

    Frazier, A.W.; Dillard, E.F.; Thrasher, R.D.; Waerstad, K.R.; Hunter, S.R.; Kohler, J.J.; Scheib, R.M.

    1991-02-01

    This bulletin is a compilation of crystallographic data collected at NFERC on 450 fertilizer-related compounds. In TVA`s fertilizer R and D program, petrographic examination, XRD, and infrared spectroscopy are combined with conventional chemical analysis methods in identifying the individual compounds that occur in fertilizer materials. This handbook brings together the results of these characterization studies and supplemental crystallographic data from the literature. It is in one-compound-per-page, loose-leaf format, ordered alphabetically by IUPAC name. Indexes provided include IUPAC name, formula, group, alternate formula, synonyms, x-ray data, optical data. Tables are given for solids, compounds in commercial MAP and DAP, and matrix materials in phosphate rock.

  6. Extemporaneous compounding of medicated ointments.

    PubMed

    Nagel, Karen; Ali, Fatima; Al-Khudari, Sarah; Khan, Ayesha; Patel, Khushbu; Patel, Nikunj; Desai, Archana

    2010-01-01

    Topical preparations represent a large percentage of compounded prescriptions, particularly in the area of dermatology. Properties of ointment bases vary greatly, and active ingredients are frequently added as aqueous or alcoholic solutions. Currently, there are no quantitative guidelines stating the various water and alcohol absorption capacity of different bases. A short experiment was designed to quantitate the amount of water or alcohol that could be absorbed by a series of ointment bases of varying types. Our findings may be used to assist compounding pharmacists in deciding what base is most suitable to use when considering the amount of water, alcohol, or any similar solvent needed to compound the preparation. A general overview of issues related to topical medication compounding is also provided in this article.

  7. MECHANICAL BEHAVIOR OF INTERMETALLIC COMPOUNDS.

    DTIC Science & Technology

    AGING(MATERIALS), AGING(MATERIALS), INTERMETALLIC COMPOUNDS, VANADIUM ALLOYS, COBALT ALLOYS, NICKEL ALLOYS, MECHANICAL PROPERTIES, TEMPERATURE, TIME ... CRYSTAL STRUCTURE, MICROSTRUCTURE, HARDNESS, TRANSFORMATIONS, ELECTRICAL RESISTANCE, MEASUREMENT, MICROSCOPY, ALLOYS, METALLOGRAPHY, X RAY DIFFRACTION.

  8. Photochemical dimerization of organic compounds

    DOEpatents

    Crabtree, Robert H.; Brown, Stephen H.; Muedas, Cesar A.; Ferguson, Richard R.

    1992-01-01

    At least one of selectivity and reaction rate of photosensitized vapor phase dimerizations, including dehydrodimerizations, hydrodimerizations and cross-dimerizations of saturated and unsaturated organic compounds is improved by conducting the dimerization in the presence of hydrogen or nitrous oxide.

  9. Polishing compound for plastic surfaces

    DOEpatents

    Stowell, M.S.

    1991-01-01

    This invention is comprised of a polishing compound for plastic materials. The compound includes approximately by approximately by weight 25 to 80 parts at least one petroleum distillate lubricant, 1 to 12 parts mineral spirits, 50 to 155 parts abrasive paste, and 15 to 60 parts water. Preferably, the compound includes approximately 37 to 42 parts at least one petroleum distillate lubricant, up to 8 parts mineral spirits, 95 to 110 parts abrasive paste, and 50 to 55 parts water. The proportions of the ingredients are varied in accordance with the particular application. The compound is used on PLEXIGLAS{trademark}, LEXAN{trademark}, LUCITE{trademark}, polyvinyl chloride (PVC), and similar plastic materials whenever a smooth, clear polished surface is desired.

  10. Enzymatic synthesis of organophosphorus compounds

    NASA Astrophysics Data System (ADS)

    Kolodiazhnyi, Oleg I.

    2011-09-01

    Data on biocatalytic methods for the preparation of chiral organophosphorus compounds are generalized and described systematically. Various examples of enzymatic and microbiological synthesis of hydroxyphosphonates, aminophosphonates, phosphinites, phosphine oxides and tertiary phosphines are discussed. The bibliography includes 154 references.

  11. Fourth symposium on macrocyclic compounds

    SciTech Connect

    Christensen, J. J.; Izatt, R. M.

    1980-01-01

    Both theoretical and experimental aspects of the properties and behavior of synthetic and naturally occurring macrocyclic compounds are covered in this symposium. This document contains abstracts of the papers. (DLC)

  12. THE FERROELECTRIC AND STRUCTURAL PROPERTIES OF HAFNIUM OXIDE COMPOUNDS,

    DTIC Science & Technology

    HAFNIUM COMPOUNDS, OXIDES), (* FERROELECTRICITY , HAFNIUM COMPOUNDS), (*CRYSTAL STRUCTURE, HAFNIUM COMPOUNDS), DIELECTRIC PROPERTIES, HYSTERESIS... FERROELECTRIC MATERIALS, SOLID SOLUTIONS, X RAY DIFFRACTION, CRYSTAL LATTICES, LOW TEMPERATURE, CALCIUM COMPOUNDS, STRONTIUM COMPOUNDS, LEAD COMPOUNDS, BARIUM COMPOUNDS

  13. Aza compounds as anion receptors

    DOEpatents

    Lee, Hung Sui; Yang, Xiao-Qing; McBreen, James

    1998-01-06

    A family of aza-ether based compounds including linear, multi-branched and aza-crown ethers is provided. When added to non-aqueous battery electrolytes, the family of aza-ether based compounds acts as neutral receptors to complex the anion moiety of the electrolyte salt thereby increasing the conductivity and the transference number of Li.sup.+ ion in alkali metal batteries.

  14. Aza compounds as anion receptors

    DOEpatents

    Lee, H.S.; Yang, X.Q.; McBreen, J.

    1998-01-06

    A family of aza-ether based compounds including linear, multi-branched and aza-crown ethers is provided. When added to non-aqueous battery electrolytes, the family of aza-ether based compounds acts as neutral receptors to complex the anion moiety of the electrolyte salt thereby increasing the conductivity and the transference number of Li{sup +} ion in alkali metal batteries. 3 figs.

  15. The Multilinear Compound Gaussian Distribution

    DTIC Science & Technology

    2012-05-01

    which we call the Multilinear Compound Gaussian (MCG) distribution, subsumes both GSM [1] and the previously developed MICA [3-4] distributions as...modeling various natural phenomena of interest. Index Terms— GSM, MICA , MCG, Bayesian, Nonlinear I. INTRODUCTION The compound Gaussian (CG) model—also...We will see how the MCG model developed subsumes both CG and the previously developed multilinear ICA ( MICA ) distribution [3-4] as complementary

  16. Two compounds from Peucedanum dissolutum.

    PubMed

    Wu, Xian-Li; Li, Yi; Kong, Ling-Yi; Min, Zhi-Da

    2004-12-01

    A new compound, 3'(R)-O-beta-D-glucopyranosyl-3',4'-dihydroxanthyletin (1), and a known compound, prim-O-glucosylcimifugin (2), were isolated from the roots of Peucedanum dissolutum. The structure of 1 was elucidated by spectral evidence and chemical reaction. The NMR signals of carbons and protons of 2 were assigned for the first time by analysis of (1)H-(1)H COSY, HMQC and HMBC spectra.

  17. Compound Walls For Vacuum Chambers

    NASA Technical Reports Server (NTRS)

    Frazer, Robert E.

    1988-01-01

    Proposed compound-wall configuration enables construction of large high-vacuum chambers without having to use thick layers of expensive material to obtain necessary strength. Walls enclose chambers more than 1 m in diameter and several kilometers long. Compound wall made of strong outer layer of structural-steel culvert pipe welded to thin layer of high-quality, low-outgassing stainless steel.

  18. Miniature curved artificial compound eyes.

    PubMed

    Floreano, Dario; Pericet-Camara, Ramon; Viollet, Stéphane; Ruffier, Franck; Brückner, Andreas; Leitel, Robert; Buss, Wolfgang; Menouni, Mohsine; Expert, Fabien; Juston, Raphaël; Dobrzynski, Michal Karol; L'Eplattenier, Geraud; Recktenwald, Fabian; Mallot, Hanspeter A; Franceschini, Nicolas

    2013-06-04

    In most animal species, vision is mediated by compound eyes, which offer lower resolution than vertebrate single-lens eyes, but significantly larger fields of view with negligible distortion and spherical aberration, as well as high temporal resolution in a tiny package. Compound eyes are ideally suited for fast panoramic motion perception. Engineering a miniature artificial compound eye is challenging because it requires accurate alignment of photoreceptive and optical components on a curved surface. Here, we describe a unique design method for biomimetic compound eyes featuring a panoramic, undistorted field of view in a very thin package. The design consists of three planar layers of separately produced arrays, namely, a microlens array, a neuromorphic photodetector array, and a flexible printed circuit board that are stacked, cut, and curved to produce a mechanically flexible imager. Following this method, we have prototyped and characterized an artificial compound eye bearing a hemispherical field of view with embedded and programmable low-power signal processing, high temporal resolution, and local adaptation to illumination. The prototyped artificial compound eye possesses several characteristics similar to the eye of the fruit fly Drosophila and other arthropod species. This design method opens up additional vistas for a broad range of applications in which wide field motion detection is at a premium, such as collision-free navigation of terrestrial and aerospace vehicles, and for the experimental testing of insect vision theories.

  19. Bioaccessibility testing of cobalt compounds.

    PubMed

    Stopford, Woodhall; Turner, John; Cappellini, Danielle; Brock, Tom

    2003-08-01

    Testing of metal compounds for solubility in artificial fluids has been used for many years to assist determining human health risk from exposure to specific compounds of concern. In lieu of obtaining bioavailability data from samples of urine, blood, or other tissues, these studies measured solubility of compounds in various artificial fluids as a surrogate for bioavailability. In this context, the measurement of metal "bioaccessibility" can be used as an in vitro substitute for measuring metal bioavailability. Bioaccessibility can be defined as a value representing the availability of metal for absorption when dissolved in in vitro surrogates of body fluids or juices. The aim of this study was to measure and compare the bioaccessibility of selected cobalt compounds in artificial human tissue fluids and human serum. A second aim was to initiate studies to experimentally validate an in vitro methodology that would provide a conservative estimate of cobalt bioavailability in the assessment of dose from human exposure to various species of cobalt compounds. This study evaluated the bioaccessibility of cobalt(II) from 11 selected cobalt compounds and an alloy in 2 physical forms in 5 surrogate human tissue fluids and human serum. Four (4) separate extraction times were used up to 72 hours. The effect of variables such as pH, dissolution time, and mass-ion effect on cobalt bioaccessibility were assessed as well. We found that the species of cobalt compound as well as the physico-chemical properties of the surrogate fluids, especially pH, had a major impact on cobalt solubility. Cobalt salts such as cobalt(II) sulfate heptahydrate were highly soluble, whereas cobalt alloys used in medical implants and cobalt aluminate spinels used as pigments, showed minimal dissolution over the period of the assay.

  20. Host compounds for red phosphorescent OLEDs

    DOEpatents

    Xia, Chuanjun; Cheon, Kwang -Ohk

    2015-08-25

    Novel compounds containing a triphenylene moiety linked to an .alpha..beta. connected binaphthyl ring system are provided. These compounds have surprisingly good solubility in organic solvents and are useful as host compounds in red phosphorescent OLEDs.

  1. Method for purifying bidentate organophosphorus compounds

    DOEpatents

    Schulz, Wallace W.

    1977-01-01

    Bidentate organophosphorus compounds useful for extracting actinide elements from acidic nuclear waste solutions are purified of undesirable acidic impurities by contacting the compounds with ethylene glycol which preferentially extracts the impurities found in technical grade bidentate compounds.

  2. Extraterrestrial Organic Compounds in Meteorites

    NASA Technical Reports Server (NTRS)

    Botta, Oliver; Bada, Jeffrey L.; Meyer, Michael (Technical Monitor)

    2003-01-01

    Many organic compounds or their precursors found in meteorites originated in the interstellar or circumstellar medium and were later incorporated into planetesimals during the formation of the solar system. There they either survived intact or underwent further processing to synthesize secondary products on the meteorite parent body. The most distinct feature of CI and CM carbonaceous chondrites, two types of stony meteorites, is their high carbon content (up to 3% of weight), either in the form of carbonates or of organic compounds. The bulk of the organic carbon consists of an insoluble macromolecular material with a complex structure. Also present is a soluble organic fraction, which has been analyzed by several separation and analytical procedures. Low detection limits can be achieved by derivatization of the organic molecules with reagents that allow for analysis by gas chromatography/mass spectroscopy and high performance liquid chromatography. The CM meteorite Murchison has been found to contain more than 70 extraterrestrial amino acids and several other classes of compounds including carboxylic acids, hydroxy carboxylic acids, sulphonic and phosphonic acids, aliphatic, aromatic and polar hydrocarbons, fullerenes, heterocycles as well as carbonyl compounds, alcohols, amines and amides. The organic matter was found to be enriched in deuterium, and distinct organic compounds show isotopic enrichments of carbon and nitrogen relative to terrestrial matter.

  3. Extraterrestrial Organic Compounds in Meteorites

    NASA Technical Reports Server (NTRS)

    Botta, Oliver; Bada, Jeffrey L.; Meyer, Michael (Technical Monitor)

    2003-01-01

    Many organic compounds or their precursors found in meteorites originated in the interstellar or circumstellar medium and were later incorporated into planetesimals during the formation of the solar system. There they either survived intact or underwent further processing to synthesize secondary products on the meteorite parent body. The most distinct feature of CI and CM carbonaceous chondrites, two types of stony meteorites, is their high carbon content (up to 3% of weight), either in the form of carbonates or of organic compounds. The bulk of the organic carbon consists of an insoluble macromolecular material with a complex structure. Also present is a soluble organic fraction, which has been analyzed by several separation and analytical procedures. Low detection limits can be achieved by derivatization of the organic molecules with reagents that allow for analysis by gas chromatography/mass spectroscopy and high performance liquid chromatography. The CM meteorite Murchison has been found to contain more than 70 extraterrestrial amino acids and several other classes of compounds including carboxylic acids, hydroxy carboxylic acids, sulphonic and phosphonic acids, aliphatic, aromatic and polar hydrocarbons, fullerenes, heterocycles as well as carbonyl compounds, alcohols, amines and amides. The organic matter was found to be enriched in deuterium, and distinct organic compounds show isotopic enrichments of carbon and nitrogen relative to terrestrial matter.

  4. Blue Photoluminescence From Silacyclobutene Compounds

    NASA Astrophysics Data System (ADS)

    Pernisz, Udo

    1999-04-01

    Organosilicon compounds in which the Si atom is bound to an aromatic moiety such as a phenyl group, exhibit strong blue photoluminescence when excited with UV light (for example at a wavelength of 337 nm). This phenomenon was investigated quantitatively at room temperature and at the temperature of liquid nitrogen (78 K) by measuring the emission and excitation spectra of the total luminescence, and of the phosphorescence, for a silacyclobutene compound in which two phenyl groups are joined across the C=C double bond of the ring. The effect of a series of organic substituents on the Si atom was investigated as well as the time dependence of the phosphorescence intensity decay for this class of materials. A tentative model of the energy levels in this compound is proposed. The observation of visible blue emission -- in contrast to photoluminescence in the UV from the aromatic groups -- is explained by the Si-C bond lowering the energy of the molecular orbitals, an effect that is currently under study for a range of Si-containing compounds. Synthesis of the silacyclobutene compounds was performed at the laboratory of Prof. N. Auner, now at J.W. Goethe Universität, Frankfurt, Germany. His contributions, and those of his collaborators, to the work reported here are gratefully acknowledged.

  5. Cytotoxic Compounds from Brucea mollis

    PubMed Central

    Tung, Mai Hung Thanh; Đuc, Ho Viet; Huong, Tran Thu; Duong, Nguyen Thanh; Phuong, Do Thi; Thao, Do Thi; Tai, Bui Huu; Kim, Young Ho; Bach, Tran The; Cuong, Nguyen Manh

    2013-01-01

    Ten compounds, including soulameanone (1), isobruceine B (2), 9-methoxy-canthin-6-one (3), bruceolline F (4), niloticine (5), octatriacontan-1-ol (6), bombiprenone (7), α-tocopherol (8), inosine (9), and apigenin 7-O-β-D-glucopyranoside (10), were isolated from the leaves, stems, and roots of Brucea mollis Wall. ex Kurz. Their structures were determined using one-and two-dimensional NMR spectroscopy and mass spectrometry. All compounds were evaluated for their cytotoxic activity against KB (human carcinoma of the mouth), LU-1 (human lung adenocarcinoma), LNCaP (human prostate adeno-carcinoma), and HL-60 (human promyelocytic leukemia) cancer cell lines. Compound 2 showed significant cytotoxic activity against KB, LU-1, LNCaP, and HL-60 cancer cells with IC50 values of 0.39, 0.40, 0.34, and 0.23 μg/mL, respectively. In addition, compounds 3 and 5 showed significant cytotoxic activity against KB, LU-1, LNCaP, and HL-60 cancer cells with IC50 values around 1–4 μg/mL. Compounds 9-methoxycanthin-6-one (3) and niloticine (5) have been discovered for the first time from the Brucea genus. PMID:24106661

  6. Antitumor Compounds from Marine Actinomycetes

    PubMed Central

    Olano, Carlos; Méndez, Carmen; Salas, José A.

    2009-01-01

    Chemotherapy is one of the main treatments used to combat cancer. A great number of antitumor compounds are natural products or their derivatives, mainly produced by microorganisms. In particular, actinomycetes are the producers of a large number of natural products with different biological activities, including antitumor properties. These antitumor compounds belong to several structural classes such as anthracyclines, enediynes, indolocarbazoles, isoprenoides, macrolides, non-ribosomal peptides and others, and they exert antitumor activity by inducing apoptosis through DNA cleavage mediated by topoisomerase I or II inhibition, mitochondria permeabilization, inhibition of key enzymes involved in signal transduction like proteases, or cellular metabolism and in some cases by inhibiting tumor-induced angiogenesis. Marine organisms have attracted special attention in the last years for their ability to produce interesting pharmacological lead compounds. PMID:19597582

  7. Gallium-containing anticancer compounds

    PubMed Central

    Chitambar, Christopher R

    2013-01-01

    There is an ever pressing need to develop new drugs for the treatment of cancer. Gallium nitrate, a group IIIa metal salt, inhibits the proliferation of tumor cells in vitro and in vivo and has shown activity against non-Hodgkin’s lymphoma and bladder cancer in clinical trials. Gallium can function as an iron mimetic and perturb iron-dependent proliferation and other iron-related processes in tumor cells. Gallium nitrate lacks cross resistance with conventional chemotherapeutic drugs and is not myelosuppressive; it can be used when other drugs have failed or when the blood count is low. Given the therapeutic potential of gallium, newer generations of gallium compounds are now in various phases of preclinical and clinical development. These compounds hold the promise of greater anti-tumor activity against a broader spectrum of cancers. The development of gallium compounds for cancer treatment and their mechanisms of action will be discussed. PMID:22800370

  8. Gallium-containing anticancer compounds.

    PubMed

    Chitambar, Christopher R

    2012-06-01

    There is an ever pressing need to develop new drugs for the treatment of cancer. Gallium nitrate, a group IIIa metal salt, inhibits the proliferation of tumor cells in vitro and in vivo and has shown activity against non-Hodgkin's lymphoma and bladder cancer in clinical trials. Gallium can function as an iron mimetic and perturb iron-dependent proliferation and other iron-related processes in tumor cells. Gallium nitrate lacks crossresistance with conventional chemotherapeutic drugs and is not myelosuppressive; it can be used when other drugs have failed or when the blood count is low. Given the therapeutic potential of gallium, newer generations of gallium compounds are now in various phases of preclinical and clinical development. These compounds hold the promise of greater anti-tumor activity against a broader spectrum of cancers. The development of gallium compounds for cancer treatment and their mechanisms of action will be discussed.

  9. Volatile compounds from Melicope obscura.

    PubMed

    Smadja, Jacqueline; Strasberg, Dominique; Legoff, Géraldine; Gauvin-Bialecki, Anne

    2010-02-01

    To evaluate the interpopulation variability of volatile compounds in Melicope obscura, four samples representing four populations were collected all over the distribution area of the species in Reunion Island (Indian Ocean). The samples were extracted by hydrodistillation, and analyzed using GC/FID and GC/MS techniques. The study revealed that, in the four essential oils obtained, oxygenated sesquiterpenes were one of the major chemical classes (9.2-35.2%), mainly consisting of a new compound, (+)-6-ethenyl-2-hydroxy-6,10-dimethylundeca-2,9-dien-4-one (1), called melicopenol (8.6-30.1%). The compound was isolated by column chromatography and identified by spectral analyses including 1D- and 2D-NMR.

  10. Biodegradation of halogenated organic compounds.

    PubMed Central

    Chaudhry, G R; Chapalamadugu, S

    1991-01-01

    In this review we discuss the degradation of chlorinated hydrocarbons by microorganisms, emphasizing the physiological, biochemical, and genetic basis of the biodegradation of aliphatic, aromatic, and polycyclic compounds. Many environmentally important xenobiotics are halogenated, especially chlorinated. These compounds are manufactured and used as pesticides, plasticizers, paint and printing-ink components, adhesives, flame retardants, hydraulic and heat transfer fluids, refrigerants, solvents, additives for cutting oils, and textile auxiliaries. The hazardous chemicals enter the environment through production, commercial application, and waste. As a result of bioaccumulation in the food chain and groundwater contamination, they pose public health problems because many of them are toxic, mutagenic, or carcinogenic. Although synthetic chemicals are usually recalcitrant to biodegradation, microorganisms have evolved an extensive range of enzymes, pathways, and control mechanisms that are responsible for catabolism of a wide variety of such compounds. Thus, such biological degradation can be exploited to alleviate environmental pollution problems. The pathways by which a given compound is degraded are determined by the physical, chemical, and microbiological aspects of a particular environment. By understanding the genetic basis of catabolism of xenobiotics, it is possible to improve the efficacy of naturally occurring microorganisms or construct new microorganisms capable of degrading pollutants in soil and aquatic environments more efficiently. Recently a number of genes whose enzyme products have a broader substrate specificity for the degradation of aromatic compounds have been cloned and attempts have been made to construct gene cassettes or synthetic operons comprising these degradative genes. Such gene cassettes or operons can be transferred into suitable microbial hosts for extending and custom designing the pathways for rapid degradation of recalcitrant

  11. Hydrophobic Compounds Reshape Membrane Domains

    PubMed Central

    Barnoud, Jonathan; Rossi, Giulia; Marrink, Siewert J.; Monticelli, Luca

    2014-01-01

    Cell membranes have a complex lateral organization featuring domains with distinct composition, also known as rafts, which play an essential role in cellular processes such as signal transduction and protein trafficking. In vivo, perturbations of membrane domains (e.g., by drugs or lipophilic compounds) have major effects on the activity of raft-associated proteins and on signaling pathways, but they are difficult to characterize because of the small size of the domains, typically below optical resolution. Model membranes, instead, can show macroscopic phase separation between liquid-ordered and liquid-disordered domains, and they are often used to investigate the driving forces of membrane lateral organization. Studies in model membranes have shown that some lipophilic compounds perturb membrane domains, but it is not clear which chemical and physical properties determine domain perturbation. The mechanisms of domain stabilization and destabilization are also unknown. Here we describe the effect of six simple hydrophobic compounds on the lateral organization of phase-separated model membranes consisting of saturated and unsaturated phospholipids and cholesterol. Using molecular simulations, we identify two groups of molecules with distinct behavior: aliphatic compounds promote lipid mixing by distributing at the interface between liquid-ordered and liquid-disordered domains; aromatic compounds, instead, stabilize phase separation by partitioning into liquid-disordered domains and excluding cholesterol from the disordered domains. We predict that relatively small concentrations of hydrophobic species can have a broad impact on domain stability in model systems, which suggests possible mechanisms of action for hydrophobic compounds in vivo. PMID:25299598

  12. Organosulfur compounds and cardiovascular disease.

    PubMed

    Vazquez-Prieto, Marcela A; Miatello, Roberto M

    2010-12-01

    Epidemiological studies have shown an inverse relationship between consumption of fruits and vegetables and the risk of cardiovascular disease. Phytochemicals are non-nutritional chemical compounds found in small quantities in fruits and vegetables with known health benefits. Among them, organosulfides are present mainly in garlic and onion characterized by their antioxidant and anti-inflammatory properties, and isothiocyanates in cruciferous vegetables have anticarcinogenic effects in experimental models. In this review, we are focusing on the main biological studies regarding the beneficial effect of organosulfur compounds on their protection against cardiovascular disease.

  13. Electronic Configuration of Yb Compounds

    SciTech Connect

    Temmerman, W.M.; Szotek, Z.; Svane, A.; Strange, P.; Winter, H.; Delin, A.; Johansson, B.; Eriksson, O.; Fast, L.; Wills, J.M.

    1999-11-01

    The total energy differences between divalent and trivalent configurations of Yb ions in a number of Yb compounds are studied. Two different band theoretical methods, which differ in the treatment of the localized f electrons, are used. The results show that in all Yb compounds the valence energy differences are equal to the energy needed to localize an f electron. These valence energy differences correlate with the number of f electrons hybridizing with the conduction bands in the trivalent configuration. For divalent YbS, the pressure induced f -electron delocalization implies an intermediate valency, as also indicated by experiment. {copyright} {ital 1999} {ital The American Physical Society }

  14. Basics of compounding with tars.

    PubMed

    Allen, Loyd V

    2013-01-01

    Tar has been used throughout history for numerous purposes; from sealing the hulls of ships to sealing roofs of dwellings and even for medical purposes. Produced by destructive distillation, commonly used tars are prepared from coal and wood. Coal tar, juniper tar, and pine tar are used for various medical purposes as described in the article. Also presented are the various characteristics and uses of each tar, along with commercial products and numerous compounding formulas. Techniques used to compound with tars are also presented.

  15. Comparison of petite induction in yeast by acridines, ethidium and their photoaffinity probes.

    PubMed

    Fukunaga, M; Yielding, L W; Firth, W J; Yielding, K L

    1981-06-01

    The production of petite mutations by different acridine analogs was studied in Saccharomyces cerevisiae. Compounds with amino substituents at the 2 and 3 positions of the acridine nucleus and methylation at position 10 were effective for petite induction in growing cells but not in resting cells, while those with chloro, nitro and methoxy substituents were not effective in either resting or growing cells. Photosensitive azido derivatives of the acridines were tested to evaluate the role of covalent drug attachment for mutagenesis in resting cells. Photolysis of resting cells with 9-axido, 3-azido-6-amino-, 9-azido-10-methyl-, or 3-azido-6-amino-10-methyl-acridine was highly toxic. 3-Azido-6-amino-acridine, and especially 3-azido-10-methyl-, and 3-azido-6-amino-10-methyl-acridine, were effective petite inducers in resting cells. Thus, the photosensitive (azido) group at position 9 produced only cell killing while the azido group at position 3 and/or 6 led to effective petite induction in resting cells. In contrast, petite induction was observed only for growing cells, for dark control experiments with these compounds or with the monoazide precursor compounds.

  16. Multiple mixed-valence behavior in trans,trans-[(tpy)(Cl)2Os(III)(mu-1,3-N3)Os(III)(Cl)2(tpy)]+. An azido bridge from the reaction between trans-[Os(VI)(tpy)(Cl)2(N)]+ and NH3.

    PubMed

    Huynh, My Hang V; Meyer, Thomas J; Labouriau, Andrea; Morris, David E; White, Peter S

    2003-03-12

    Reaction between the Os(VI)-nitrido complex, trans-[OsVI(tpy)(Cl)2(N)]PF6 (tpy = 2,2':6',2' '-terpyridine), and ammonia (NH3) under N2 in dry CH3CN gives the mu-1,3-azido bridged [OsII-N3-OsII]- dimer, trans,trans-NH4[(tpy)(Cl)2OsII(N3)OsII(Cl)2(tpy)]. It undergoes air oxidation to give the [OsIII-N3-OsIII]+ analogue, trans,trans-[(tpy)(Cl)2OsIII(N3)OsIII(Cl)2(tpy)]PF6 ([OsIII-N3-OsIII]PF6), which has been isolated and characterized. The structural formulation as a mu-1,3-N3 bridged complex has been established by infrared and 15N NMR measurements on the 15N-labeled forms, [OsIII-14N=15N=14N-OsIII]+, [OsIII-15N=14N=15N-OsIII]+, and [OsIII-15N=15N=15N-OsIII]+. Cyclic voltammetric measurements in 0.2 M Bu4NPF6/CH3CN reveal the existence of five chemically reversible waves from 1.40 to -0.12 V for couples ranging from OsV-OsIV/OsIV-OsIV to OsIII-OsII/OsII-OsII. DeltaE1/2 values for couples adjacent to the three mixed-valence forms are 0.19 V for OsIII-OsII, 0.52 V for OsIV-OsIII, and >0.71 V for OsV-OsIV. In CH3CN at 60 degrees C, [OsIII-N3-OsIII]+ undergoes a [2 + 3] cycloaddition with CH3CN at the mu-N3- bridge followed by a solvolysis to give trans-[OsIII(tpy)(Cl)2(5-MeCN4)] and trans-[OsIII(tpy)(Cl)2(NCCH3)]PF6.

  17. Toxicology and carcinogenesis studies of mixtures of 3'-azido-3'-deoxythymidine (AZT), lamivudine (3TC), nevirapine (NVP), and nelfinavir mesylate (NFV) (Cas Nos. 30516-87-1, 134678-17-4, 129618-40-2, 159989-65-8) in B6C3F1 Mice (transplacental exposure studies).

    PubMed

    2013-01-01

    Antiretroviral drugs are used to treat patients positive for the human immunovirus HIV-1, and increasingly treatments include a combination of such drugs. The noninfected children of women who are pregnant and receiving such treatment may also be exposed to the drugs by transplacental exposure. We studied the long-term effects of such transplacental exposure in mice by exposing pregnant mice to combinations of four such antiretroviral drugs for seven days and then observing their pups for two years following birth. The four drugs studied were 3′-azido-3′-deoxythymidine (AZT), lamivudine (3TC), nevirapine (NVP), and nelfinavir mesylate (NFV). Four different sets of exposure studies were performed: exposure to AZT; to AZT plus 3TC; to AZT, 3TC, and NVP; or to AZT, 3TC, and NFV. In each of these studies, groups of pregnant females were given one of three concentrations of the drug combinations seven times though a tube directly into their stomachs, and after birth their pups were maintained with no further exposure for two years. The offspring of another group of pregnant females not treated with the drugs served as controls. At the end of the study, tissues from more than 40 sites were examined for every animal. Survival of pups whose mothers were exposed to AZT or AZT plus 3TC was similar to their controls, while the survival rates for offspring of mice exposed to AZT, 3TC, and NVP or AZT, 3TC, and NFP were lower than for controls. In most cases the body weights of pups from mothers exposed were slightly less than those of the controls. There were slight increases in the incidences of thyroid gland tumors and skin tumors in the female pups of mothers exposed to AZT alone and of lung tumors in female pups of mothers exposed to AZT plus 3TC. For offspring of mothers exposed to AZT, 3TC, and NVP there were increased incidences of skin tumors in both male and female pups, and more so in the males. We conclude that exposure to the combination of AZT, 3TC, and NVP

  18. Pentafluorosulfur Compounds for Naval Materials.

    DTIC Science & Technology

    1982-01-01

    Compounds The sulfamide , (t-BuNH) 2S02 , turned out to be a rich source of novel sulfur- nitrogen heterocycles. For example, treatment of (t-BuNH) 2 so2 with...planar and tetrahedral, and (b) the sulfamide adopts an anti(C2 ) conformation rather than the cis(Cs) conformation presumably due to minimization of

  19. Halogenated Compounds from Marine Algae

    PubMed Central

    Cabrita, Maria Teresa; Vale, Carlos; Rauter, Amélia Pilar

    2010-01-01

    Marine algae produce a cocktail of halogenated metabolites with potential commercial value. Structures exhibited by these compounds go from acyclic entities with a linear chain to complex polycyclic molecules. Their medical and pharmaceutical application has been investigated for a few decades, however other properties, such as antifouling, are not to be discarded. Many compounds were discovered in the last years, although the need for new drugs keeps this field open as many algal species are poorly screened. The ecological role of marine algal halogenated metabolites has somehow been overlooked. This new research field will provide valuable and novel insight into the marine ecosystem dynamics as well as a new approach to comprehending biodiversity. Furthermore, understanding interactions between halogenated compound production by algae and the environment, including anthropogenic or global climate changes, is a challenging target for the coming years. Research of halogenated metabolites has been more focused on macroalgae than on phytoplankton. However, phytoplankton could be a very promising material since it is the base of the marine food chain with quick adaptation to environmental changes, which undoubtedly has consequences on secondary metabolism. This paper reviews recent progress on this field and presents trends on the role of marine algae as producers of halogenated compounds. PMID:20948909

  20. Polymeric nanocomposites: compounding and performance.

    PubMed

    Utracki, L A

    2008-04-01

    Polymeric nanocomposites (PNC) are binary mixtures of strongly interacting, inorganic platelets dispersed in a polymeric matrix. For full exfoliation, the thermodynamic miscibility is required. There are three basic methods of organically-modified clay dispersion that might result in PNC: (1) in polymer solution (followed by solvent removal), (2) in a monomer (followed by polymerization), and (3) in molten polymer (compounding). Most commercial PNC are produced by the second method, but it is the third one that has the greatest promise for the plastics industry. Similarly as during the manufacture of polymer blends, the layered silicates must be compatibilized by intercalation with organic salts and/or addition of functionalized macromolecules. Compounding affects the kinetics of dispersion process, but rarely the miscibility. Melt compounding is carried out either in a single-screw (SSE) or a twin-screw extruder (TSE). Furthermore, an extensional flow mixer (EFM) might be attached to an extruder. Two versions of EFM were evaluated: (1) designed for polymer homogenization and blending, and (2) designed for dispersing nano-particles. In this review, the dispersion of organoclay in polystyrene (PS), polyamide-6 (PA-6) or in polypropylene (PP) is discussed. The PNC based on PS or PA-6 contained two components (polymer and organoclay), whereas those based on PP in addition had a compatibilizer mixture of two maleated polypropylenes. Better dispersion was found compounding PNC's in a SSE + EFM than in TSE with or without EFM. The mechanical performance (tensile, flexural and impact) was examined.

  1. Infrared Spectroscopy of Deuterated Compounds.

    ERIC Educational Resources Information Center

    MacCarthy, Patrick

    1985-01-01

    Background information, procedures used, and typical results obtained are provided for an experiment (based on the potassium bromide pressed-pellet method) involving the infrared spectroscopy of deuterated compounds. Deuteration refers to deuterium-hydrogen exchange at active hydrogen sites in the molecule. (JN)

  2. The Compound Atwood Machine Problem

    ERIC Educational Resources Information Center

    Coelho, R. Lopes

    2017-01-01

    The present paper accounts for progress in physics teaching in the sense that a problem, which has been closed to students for being too difficult, is gained for the high school curriculum. This problem is the compound Atwood machine with three bodies. Its introduction into high school classes is based on a recent study on the weighing of an…

  3. Compound Cuing in Free Recall

    ERIC Educational Resources Information Center

    Lohnas, Lynn J.; Kahana, Michael J.

    2014-01-01

    According to the retrieved context theory of episodic memory, the cue for recall of an item is a weighted sum of recently activated cognitive states, including previously recalled and studied items as well as their associations. We show that this theory predicts there should be compound cuing in free recall. Specifically, the temporal contiguity…

  4. Theory of Compound Liquid Drops

    NASA Technical Reports Server (NTRS)

    Saffren, M. M.; Elleman, D. D.; Rhim, W. K.

    1983-01-01

    Dynamic behavior is analyzed for drop within drop within infinite fluid. Report gives theoretical basis for understanding behavior of compound drops. Aids in planning and interpreting experiments in laboratory, spacecraft, and research aircraft. Provides insight into fabrication of target pellets for nuclear fusion.

  5. Compound Cuing in Free Recall

    ERIC Educational Resources Information Center

    Lohnas, Lynn J.; Kahana, Michael J.

    2014-01-01

    According to the retrieved context theory of episodic memory, the cue for recall of an item is a weighted sum of recently activated cognitive states, including previously recalled and studied items as well as their associations. We show that this theory predicts there should be compound cuing in free recall. Specifically, the temporal contiguity…

  6. Infrared Spectroscopy of Deuterated Compounds.

    ERIC Educational Resources Information Center

    MacCarthy, Patrick

    1985-01-01

    Background information, procedures used, and typical results obtained are provided for an experiment (based on the potassium bromide pressed-pellet method) involving the infrared spectroscopy of deuterated compounds. Deuteration refers to deuterium-hydrogen exchange at active hydrogen sites in the molecule. (JN)

  7. Cerium Oxide and Cerium Compounds

    Integrated Risk Information System (IRIS)

    EPA / 635 / R - 08 / 002F www.epa.gov / iris TOXICOLOGICAL REVIEW OF Cerium Oxide and Cerium Compounds ( CAS No . 1306 - 38 - 3 ) In Support of Summary Information on the Integrated Risk Information System ( IRIS ) September 2009 U.S . Environmental Protection Agency Washington , DC ii DISCLAIMER Th

  8. Students' Categorizations of Organic Compounds

    ERIC Educational Resources Information Center

    Domin, Daniel S.; Al-Masum, Mohammad; Mensah, John

    2008-01-01

    Categorization is a fundamental psychological ability necessary for problem solving and many other higher-level cognitive tasks. In organic chemistry, students must establish groupings of different chemical compounds in order not only to solve problems, but also to understand course content. Classic models of categorization emphasize similarity as…

  9. Antifouling Compounds from Marine Macroalgae.

    PubMed

    Dahms, Hans Uwe; Dobretsov, Sergey

    2017-08-28

    Marine macroalgae produce a wide variety of biologically-active metabolites that have been developed into commercial products, such as antibiotics, immunosuppressive, anti-inflammatory, cytotoxic agents, and cosmetic products. Many marine algae remain clean over longer periods of time, suggesting their strong antifouling potential. Isolation of biogenic compounds and the determination of their structure could provide leads for the development of environmentally-friendly antifouling paints. Isolated substances with potent antifouling activity belong to fatty acids, lipopeptides, amides, alkaloids, lactones, steroids, terpenoids, and pyrroles. It is unclear as yet to what extent symbiotic microorganisms are involved in the synthesis of these compounds. Algal secondary metabolites have the potential to be produced commercially using genetic and metabolic engineering techniques. This review provides an overview of publications from 2010 to February 2017 about antifouling activity of green, brown, and red algae. Some researchers were focusing on antifouling compounds of brown macroalgae, while metabolites of green algae received less attention. Several studies tested antifouling activity against bacteria, microalgae and invertebrates, but in only a few studies was the quorum sensing inhibitory activity of marine macroalgae tested. Rarely, antifouling compounds from macroalgae were isolated and tested in an ecologically-relevant way.

  10. Making Models of Chemical Compounds.

    ERIC Educational Resources Information Center

    Hoehn, Robert G.

    1992-01-01

    Describes the benefits and techniques of having students create models of chemical compounds. This hands-on approach uses colored paper and other inexpensive materials to construct the models. A step-by-step approach provides objectives, materials, an explanation on how to calculate chemical ratios, procedures, follow-up activities, and a resource…

  11. Halogenated compounds from marine algae.

    PubMed

    Cabrita, Maria Teresa; Vale, Carlos; Rauter, Amélia Pilar

    2010-08-09

    Marine algae produce a cocktail of halogenated metabolites with potential commercial value. Structures exhibited by these compounds go from acyclic entities with a linear chain to complex polycyclic molecules. Their medical and pharmaceutical application has been investigated for a few decades, however other properties, such as antifouling, are not to be discarded. Many compounds were discovered in the last years, although the need for new drugs keeps this field open as many algal species are poorly screened. The ecological role of marine algal halogenated metabolites has somehow been overlooked. This new research field will provide valuable and novel insight into the marine ecosystem dynamics as well as a new approach to comprehending biodiversity. Furthermore, understanding interactions between halogenated compound production by algae and the environment, including anthropogenic or global climate changes, is a challenging target for the coming years. Research of halogenated metabolites has been more focused on macroalgae than on phytoplankton. However, phytoplankton could be a very promising material since it is the base of the marine food chain with quick adaptation to environmental changes, which undoubtedly has consequences on secondary metabolism. This paper reviews recent progress on this field and presents trends on the role of marine algae as producers of halogenated compounds.

  12. The compound Atwood machine problem

    NASA Astrophysics Data System (ADS)

    Lopes Coelho, R.

    2017-05-01

    The present paper accounts for progress in physics teaching in the sense that a problem, which has been closed to students for being too difficult, is gained for the high school curriculum. This problem is the compound Atwood machine with three bodies. Its introduction into high school classes is based on a recent study on the weighing of an Atwood machine.

  13. Compounding errors in 2 dogs receiving anticonvulsants.

    PubMed

    McConkey, Sandra E; Walker, Susan; Adams, Cathy

    2012-04-01

    Two cases that involve drug compounding errors are described. One dog exhibited increased seizure activity due to a compounded, flavored phenobarbital solution that deteriorated before the expiration date provided by the compounder. The other dog developed clinical signs of hyperkalemia and bromine toxicity following a 5-fold compounding error in the concentration of potassium bromide (KBr).

  14. Large Constituent Families Help Children Parse Compounds

    ERIC Educational Resources Information Center

    Krott, Andrea; Nicoladis, Elena

    2005-01-01

    The family size of the constituents of compound words, or the number of compounds sharing the constituents, has been shown to affect adults' access to compound words in the mental lexicon. The present study was designed to see if family size would affect children's segmentation of compounds. Twenty-five English-speaking children between 3;7 and…

  15. Bacterial Degradation of Aromatic Compounds

    PubMed Central

    Seo, Jong-Su; Keum, Young-Soo; Li, Qing X.

    2009-01-01

    Aromatic compounds are among the most prevalent and persistent pollutants in the environment. Petroleum-contaminated soil and sediment commonly contain a mixture of polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatics. Aromatics derived from industrial activities often have functional groups such as alkyls, halogens and nitro groups. Biodegradation is a major mechanism of removal of organic pollutants from a contaminated site. This review focuses on bacterial degradation pathways of selected aromatic compounds. Catabolic pathways of naphthalene, fluorene, phenanthrene, fluoranthene, pyrene, and benzo[a]pyrene are described in detail. Bacterial catabolism of the heterocycles dibenzofuran, carbazole, dibenzothiophene, and dibenzodioxin is discussed. Bacterial catabolism of alkylated PAHs is summarized, followed by a brief discussion of proteomics and metabolomics as powerful tools for elucidation of biodegradation mechanisms. PMID:19440284

  16. Superconductivity in graphite intercalation compounds

    DOE PAGES

    Smith, Robert P.; Weller, Thomas E.; Howard, Christopher A.; ...

    2015-02-26

    This study examines the field of superconductivity in the class of materials known as graphite intercalation compounds which has a history dating back to the 1960s. This paper recontextualizes the field in light of the discovery of superconductivity in CaC₆ and YbC₆ in 2005. In what follows, we outline the crystal structure and electronic structure of these and related compounds. We go on to experiments addressing the superconducting energy gap, lattice dynamics, pressure dependence, and how this relates to theoretical studies. The bulk of the evidence strongly supports a BCS superconducting state. However, important questions remain regarding which electronic statesmore » and phonon modes are most important for superconductivity and whether current theoretical techniques can fully describe the dependence of the superconducting transition temperature on pressure and chemical composition.« less

  17. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, Jr., Lawrence A.; Arganbright, Robert P.; Hearn, Dennis

    1993-01-01

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C.sub.2 to C.sub.10 olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80.degree. C. to 500.degree. C., using as the catalyst a mole sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene to about the mid point of the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms.

  18. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, L.A. Jr.; Arganbright, R.P.; Hearn, D.

    1994-06-14

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C[sub 2] to C[sub 10] olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80 C to 500 C, using as the catalyst a molecular sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene below the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms. 1 fig.

  19. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, L.A. Jr.; Arganbright, R.P.; Hearn, D.

    1993-09-07

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C[sub 2] to C[sub 10] olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80 C to 500 C, using as the catalyst a molecular sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene to about the mid point of the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms. 1 figures.

  20. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, Jr., Lawrence A.

    1989-01-01

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C.sub.2 to C.sub.10 olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80.degree. C. to 500.degree. C., using as the catalyst a mole sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene below the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms.

  1. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, L.A. Jr.

    1989-07-18

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C[sub 2] to C[sub 10] olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80 C to 500 C, using as the catalyst a mole sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene below the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms. 1 fig.

  2. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, Jr., Lawrence A.; Arganbright, Robert P.; Hearn, Dennis

    1994-01-01

    Aromatic compounds are alkylated in a catalytic distillation, wherein the catalyst structure also serves as a distillation component by contacting the aromatic compound with a C.sub.2 to C.sub.10 olefin in the catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of 80.degree. C. to 500.degree. C., using as the catalyst a mole sieve characterized as acidic or an acidic cation exchange resin. For example, ethyl benzene is produced by feeding ethylene below the catalyst bed while benzene is conveniently added through the reflux in molar excess to that required to react with ethylene, thereby reacting substantially all of the ethylene and recovering benzene as the principal overhead and ethyl benzene in the bottoms.

  3. Superconductivity in graphite intercalation compounds

    NASA Astrophysics Data System (ADS)

    Smith, Robert P.; Weller, Thomas E.; Howard, Christopher A.; Dean, Mark P. M.; Rahnejat, Kaveh C.; Saxena, Siddharth S.; Ellerby, Mark

    2015-07-01

    The field of superconductivity in the class of materials known as graphite intercalation compounds has a history dating back to the 1960s (Dresselhaus and Dresselhaus, 1981; Enoki et al., 2003). This paper recontextualizes the field in light of the discovery of superconductivity in CaC6 and YbC6 in 2005. In what follows, we outline the crystal structure and electronic structure of these and related compounds. We go on to experiments addressing the superconducting energy gap, lattice dynamics, pressure dependence, and how these relate to theoretical studies. The bulk of the evidence strongly supports a BCS superconducting state. However, important questions remain regarding which electronic states and phonon modes are most important for superconductivity, and whether current theoretical techniques can fully describe the dependence of the superconducting transition temperature on pressure and chemical composition.

  4. Superconductivity in graphite intercalation compounds

    SciTech Connect

    Smith, Robert P.; Weller, Thomas E.; Howard, Christopher A.; Dean, Mark P. M.; Rahnejat, Kaveh C.; Saxena, Siddharth S.; Ellerby, Mark

    2015-02-26

    This study examines the field of superconductivity in the class of materials known as graphite intercalation compounds which has a history dating back to the 1960s. This paper recontextualizes the field in light of the discovery of superconductivity in CaC₆ and YbC₆ in 2005. In what follows, we outline the crystal structure and electronic structure of these and related compounds. We go on to experiments addressing the superconducting energy gap, lattice dynamics, pressure dependence, and how this relates to theoretical studies. The bulk of the evidence strongly supports a BCS superconducting state. However, important questions remain regarding which electronic states and phonon modes are most important for superconductivity and whether current theoretical techniques can fully describe the dependence of the superconducting transition temperature on pressure and chemical composition.

  5. Quantitative analysis of endogenous compounds.

    PubMed

    Thakare, Rhishikesh; Chhonker, Yashpal S; Gautam, Nagsen; Alamoudi, Jawaher Abdullah; Alnouti, Yazen

    2016-09-05

    Accurate quantitative analysis of endogenous analytes is essential for several clinical and non-clinical applications. LC-MS/MS is the technique of choice for quantitative analyses. Absolute quantification by LC/MS requires preparing standard curves in the same matrix as the study samples so that the matrix effect and the extraction efficiency for analytes are the same in both the standard and study samples. However, by definition, analyte-free biological matrices do not exist for endogenous compounds. To address the lack of blank matrices for the quantification of endogenous compounds by LC-MS/MS, four approaches are used including the standard addition, the background subtraction, the surrogate matrix, and the surrogate analyte methods. This review article presents an overview these approaches, cite and summarize their applications, and compare their advantages and disadvantages. In addition, we discuss in details, validation requirements and compatibility with FDA guidelines to ensure method reliability in quantifying endogenous compounds. The standard addition, background subtraction, and the surrogate analyte approaches allow the use of the same matrix for the calibration curve as the one to be analyzed in the test samples. However, in the surrogate matrix approach, various matrices such as artificial, stripped, and neat matrices are used as surrogate matrices for the actual matrix of study samples. For the surrogate analyte approach, it is required to demonstrate similarity in matrix effect and recovery between surrogate and authentic endogenous analytes. Similarly, for the surrogate matrix approach, it is required to demonstrate similar matrix effect and extraction recovery in both the surrogate and original matrices. All these methods represent indirect approaches to quantify endogenous compounds and regardless of what approach is followed, it has to be shown that none of the validation criteria have been compromised due to the indirect analyses.

  6. Organophosphorus Compounds in Organic Electronics.

    PubMed

    Shameem, Muhammad Anwar; Orthaber, Andreas

    2016-07-25

    This Minireview describes recent advances of organophosphorus compounds as opto-electronic materials in the field of organic electronics. The progress of (hetero-) phospholes, unsaturated phosphanes, and trivalent and pentavalent phosphanes since 2010 is covered. The described applications of organophosphorus materials range from single molecule sensors, field effect transistors, organic light emitting diodes, to polymeric materials for organic photovoltaic applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Compound semiconductor optical waveguide switch

    DOEpatents

    Spahn, Olga B.; Sullivan, Charles T.; Garcia, Ernest J.

    2003-06-10

    An optical waveguide switch is disclosed which is formed from III-V compound semiconductors and which has a moveable optical waveguide with a cantilevered portion that can be bent laterally by an integral electrostatic actuator to route an optical signal (i.e. light) between the moveable optical waveguide and one of a plurality of fixed optical waveguides. A plurality of optical waveguide switches can be formed on a common substrate and interconnected to form an optical switching network.

  8. Triterpenes as potentially cytotoxic compounds.

    PubMed

    Chudzik, Malwina; Korzonek-Szlacheta, Ilona; Król, Wojciech

    2015-01-19

    Triterpenes are compounds of natural origin, which have numerously biological activities: anti-cancer properties, anti-inflammatory, anti-oxidative, anti-viral, anti-bacterial and anti-fungal. These substances can be isolated from plants, animals or fungi. Nowadays, when neoplasms are main cause of death, triterpenes can become an alternative method for treating cancer because of their cytotoxic properties and chemopreventive activities.

  9. Molybdenum compounds in organic synthesis

    NASA Astrophysics Data System (ADS)

    Khusnutdinov, R. I.; Oshnyakova, T. M.; Dzhemilev, U. M.

    2017-02-01

    The review presents the first analysis and systematic discussion of data published in the last 35–40 years on the use of molybdenum compounds and complexes in organic synthesis and catalysis of various ion coordination and radical reactions. Detailed account is given of the key trends in the use of molybdenum complexes as catalysts of alkene epoxidation and oxyketonation, oxidation of sulfur, nitrogen and phosphorus compounds, hydrosilylation of 1,3-dienes, ketones and aldehydes, hydrostannylation of acetylenes and hydrogermylation of norbornadienes. Considerable attention is paid to the description of new reactions and in situ generation of highly reactive hypohalites, ROX and HOX, induced by molybdenum complexes and the use of hypohalites in oxidative transformations. Data on the application of molybdenum complexes in well-known reactions are discussed, including Kharasch and Pauson–Khand reactions, allylic alkylation of C-nucleophiles, aminocarbonylation of halo derivatives and oligomerization of cyclic dienes, trienes, alkynes and 1,3-dienes. The last Section of the review considers 'unusual' organic reactions involving molybdenum compounds and complexes. The bibliography includes 257 references.

  10. Compound facial expressions of emotion

    PubMed Central

    Du, Shichuan; Tao, Yong; Martinez, Aleix M.

    2014-01-01

    Understanding the different categories of facial expressions of emotion regularly used by us is essential to gain insights into human cognition and affect as well as for the design of computational models and perceptual interfaces. Past research on facial expressions of emotion has focused on the study of six basic categories—happiness, surprise, anger, sadness, fear, and disgust. However, many more facial expressions of emotion exist and are used regularly by humans. This paper describes an important group of expressions, which we call compound emotion categories. Compound emotions are those that can be constructed by combining basic component categories to create new ones. For instance, happily surprised and angrily surprised are two distinct compound emotion categories. The present work defines 21 distinct emotion categories. Sample images of their facial expressions were collected from 230 human subjects. A Facial Action Coding System analysis shows the production of these 21 categories is different but consistent with the subordinate categories they represent (e.g., a happily surprised expression combines muscle movements observed in happiness and surprised). We show that these differences are sufficient to distinguish between the 21 defined categories. We then use a computational model of face perception to demonstrate that most of these categories are also visually discriminable from one another. PMID:24706770

  11. Neuroprotective compounds of Tilia amurensis

    PubMed Central

    Lee, Bohyung; Weon, Jin Bae; Eom, Min Rye; Jung, Youn Sik; Ma, Choong Je

    2015-01-01

    Background: Tilia amurensis (Tiliacese) has been used for anti-tumor and anti-inflammatory in Korea, China, and Japan. Objective: In this study, we isolated five compounds from T. amurensis and determined whether protected neuronal cells against glutamate-induced oxidative stress in HT22 cells. Materials and Methods: Compounds were isolated using chromatographic techniques including silica gel, Sephadex LH-20 open column and high performance liquid chromatography analysis, and evaluated neuroprotective effect in HT22 cells by 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay. Results: β-D-fructofuranosyl α-D-glucopyranoside (1), (-)-epicatechin (2), nudiposide (3), lyoniside (4), and scopoletin (5) were isolated by bioactivity-guided fractionation from the ethyl acetate fraction of T. amurensis. Among them, (-)-epicatechin, nudiposide, lyoniside, and scopoletin had significant neuroprotective activities against glutamate-injured neurotoxicity in HT22 cells. Conclusion: These results demonstrated that compound two, three, four, and five have a pronounced protective effect against glutamate-induced neurotoxicity in HT22 cells. PMID:26664019

  12. Butyltin compounds in Portuguese wines.

    PubMed

    Azenha, Manuel; Vasconcelos, Maria Teresa

    2002-04-24

    Butyltin compounds are widespread contaminants that have also been found in some wines. The purpose of the present work was to make a survey of butyltin compounds in Portuguese wines. Forty-three table wines and 14 Port wines were analyzed for butyltin contents by using solid-phase microextraction gas chromatography mass spectrometry (SPME-GC-MS). In 14% of the analyzed wine samples, measurable dibutyltin (DBT) was found at concentrations ranging between 0.05 and 0.15 microg/L as Sn. Monobutyltin (MBT) was also observed (0.05 microg/L as Sn) in just a single wine. A search for the possible sources of DBT residues found in the wines was carried out. Therefore, some plastics and oak wood used in the process of wine-making, which have been directly in contact with the musts or the wines, were studied to check their possible release of butyltins. The eventual presence of DBT was also tested directly along the vinification process, from the must to the finished product. The results suggest that high-density polyethylene containers used in the transfer of wine in an early stage of the vinification process may be the main sources of these contaminants. Therefore, it is recommendable that plastic materials to be used in wineries be previously tested for the release of butyltin compounds.

  13. Natural Compounds Modulating Mitochondrial Functions

    PubMed Central

    Gibellini, Lara; Bianchini, Elena; De Biasi, Sara; Nasi, Milena; Cossarizza, Andrea; Pinti, Marcello

    2015-01-01

    Mitochondria are organelles responsible for several crucial cell functions, including respiration, oxidative phosphorylation, and regulation of apoptosis; they are also the main intracellular source of reactive oxygen species (ROS). In the last years, a particular interest has been devoted to studying the effects on mitochondria of natural compounds of vegetal origin, quercetin (Qu), resveratrol (RSV), and curcumin (Cur) being the most studied molecules. All these natural compounds modulate mitochondrial functions by inhibiting organelle enzymes or metabolic pathways (such as oxidative phosphorylation), by altering the production of mitochondrial ROS and by modulating the activity of transcription factors which regulate the expression of mitochondrial proteins. While Qu displays both pro- and antioxidant activities, RSV and Cur are strong antioxidant, as they efficiently scavenge mitochondrial ROS and upregulate antioxidant transcriptional programmes in cells. All the three compounds display a proapoptotic activity, mediated by the capability to directly cause the release of cytochrome c from mitochondria or indirectly by upregulating the expression of proapoptotic proteins of Bcl-2 family and downregulating antiapoptotic proteins. Interestingly, these effects are particularly evident on proliferating cancer cells and can have important therapeutic implications. PMID:26167193

  14. Compound facial expressions of emotion.

    PubMed

    Du, Shichuan; Tao, Yong; Martinez, Aleix M

    2014-04-15

    Understanding the different categories of facial expressions of emotion regularly used by us is essential to gain insights into human cognition and affect as well as for the design of computational models and perceptual interfaces. Past research on facial expressions of emotion has focused on the study of six basic categories--happiness, surprise, anger, sadness, fear, and disgust. However, many more facial expressions of emotion exist and are used regularly by humans. This paper describes an important group of expressions, which we call compound emotion categories. Compound emotions are those that can be constructed by combining basic component categories to create new ones. For instance, happily surprised and angrily surprised are two distinct compound emotion categories. The present work defines 21 distinct emotion categories. Sample images of their facial expressions were collected from 230 human subjects. A Facial Action Coding System analysis shows the production of these 21 categories is different but consistent with the subordinate categories they represent (e.g., a happily surprised expression combines muscle movements observed in happiness and surprised). We show that these differences are sufficient to distinguish between the 21 defined categories. We then use a computational model of face perception to demonstrate that most of these categories are also visually discriminable from one another.

  15. Technology Roadmaps for Compound Semiconductors.

    PubMed

    Bennett, H S

    2000-01-01

    The roles cited for compound semiconductors in public versions of existing technology roadmaps from the National Electronics Manufacturing Initiative, Inc., Optoelectronics Industry Development Association, Microelectronics Advanced Research Initiative on Optoelectronic Interconnects, and Optoelectronics Industry and Technology Development Association (OITDA) are discussed and compared within the context of trends in the Si CMOS industry. In particular, the extent to which these technology roadmaps treat compound semiconductors at the materials processing and device levels will be presented for specific applications. For example, OITDA's Optical Communications Technology Roadmap directly connects the information demand of delivering 100 Mbit/s to the home to the requirement of producing 200 GHz heterojunction bipolar transistors with 30 nm bases and InP high electron mobility transistors with 100 nm gates. Some general actions for progress towards the proposed International Technology Roadmap for Compound Semiconductors (ITRCS) and methods for determining the value of an ITRCS will be suggested. But, in the final analysis, the value added by an ITRCS will depend on how industry leaders respond. The technical challenges and economic opportunities of delivering high quality digital video to consumers provide concrete examples of where the above actions and methods could be applied.

  16. Technology Roadmaps for Compound Semiconductors

    PubMed Central

    Bennett, Herbert S.

    2000-01-01

    The roles cited for compound semiconductors in public versions of existing technology roadmaps from the National Electronics Manufacturing Initiative, Inc., Optoelectronics Industry Development Association, Microelectronics Advanced Research Initiative on Optoelectronic Interconnects, and Optoelectronics Industry and Technology Development Association (OITDA) are discussed and compared within the context of trends in the Si CMOS industry. In particular, the extent to which these technology roadmaps treat compound semiconductors at the materials processing and device levels will be presented for specific applications. For example, OITDA’s Optical Communications Technology Roadmap directly connects the information demand of delivering 100 Mbit/s to the home to the requirement of producing 200 GHz heterojunction bipolar transistors with 30 nm bases and InP high electron mobility transistors with 100 nm gates. Some general actions for progress towards the proposed International Technology Roadmap for Compound Semiconductors (ITRCS) and methods for determining the value of an ITRCS will be suggested. But, in the final analysis, the value added by an ITRCS will depend on how industry leaders respond. The technical challenges and economic opportunities of delivering high quality digital video to consumers provide concrete examples of where the above actions and methods could be applied. PMID:27551615

  17. Bioactive compounds from northern plants.

    PubMed

    Hohtola, Anja

    2010-01-01

    Northern conditions are characterised by long days with much light and low temperatures during the growing season. It has been chimed that herbs and berries grown in the north are stronger tasting compared to those of southern origin. The compounds imparting aroma and color to berries and herbs are secondary metabolites which in plants mostly act as chemical means of defense. Recently, the production of secondary metabolites using plant cells has been the subject of expanding research. Light intensity, photoperiod and temperature have been reported to influence the biosynthesis of many secondary metabolites. Native wild aromatic and medicinal plant species of different families are being studied to meet the needs of raw material for the expanding industry of e.g., health-promoting food products known as nutraceutics. There are already a large number of known secondary compounds produced by plants, but the recent advances in modern extraction and analysis should enable many more as yet unknown compounds to be found, characterised and utilised. Rose root (Rhodiola rosea) is a perennial herbaceous plant which inhabits mountain regions throughout Europe, Asia and east coastal regions of North America. The extract made from the rhizomes acts as a stimulant like the Ginseng root. Roseroot has been categorized as an adaptogen and is reported to have many pharmacological properties. The biologically active components of the extract are salitroside tyrosol and cinnamic acid glycosides (rosavin, rosarin, rosin). Round-leaved sundew (Drosera rotundifolia L.) has circumboreal distribution. It inhabits nutrient-poor, moist and sunny areas such as peat bogs and wetlands. Sundew leaves are collected from the wild-type for various medicinal preparations and can be utilized in treating e.g., as an important "cough-medicine" for different respiratory diseases. The antimicrobial activity of extracts of aerial parts against various bacteria has been investigated. Drosera produces

  18. Compounding practices in a Portuguese community pharmacy.

    PubMed

    Reis, Maria; Carvalho, Maria; Rodrigues, Angelo

    2014-01-01

    All Portuguese community pharmacies have a compounding laboratory and minimum equipment for the preparation of nonsterile (traditional) compounded medicines, but a few community pharmacies specialize in compounding. At Farmácia Lordelo, the most frequently dispensed compounded medicines are oral liquids for pediatrics and multi-drug, semi-solid preparations for dermatology patients. The majority of the compounded medicines is prepared in accordance with the national galenic formulary and standardized monographs, in order to guarantee the quality and safety of the compounded medicines dispensed.

  19. Compounding USP <797>: inspection, regulation, and oversight of sterile compounding pharmacies.

    PubMed

    Kastango, Eric S

    2012-03-01

    Using USP Chapter <797> Pharmaceutical Compounding-Sterile Preparations (CSP) is now considered the standard for sterile compounding practice and safety in the United States. This is particularly important in compounding the complex formulation of parenteral nutrition.

  20. Volatile flavor compounds in yogurt: a review.

    PubMed

    Cheng, Hefa

    2010-11-01

    Considerable knowledge has been accumulated on the volatile compounds contributing to the aroma and flavor of yogurt. This review outlines the production of the major flavor compounds in yogurt fermentation and the analysis techniques, both instrumental and sensory, for quantifying the volatile compounds in yogurt. The volatile compounds that have been identified in plain yogurt are summarized, with the few key aroma compounds described in detail. Most flavor compounds in yogurt are produced from lipolysis of milkfat and microbiological transformations of lactose and citrate. More than 100 volatiles, including carbonyl compounds, alcohols, acids, esters, hydrocarbons, aromatic compounds, sulfur-containing compounds, and heterocyclic compounds, are found in yogurt at low to trace concentrations. Besides lactic acid, acetaldehyde, diacetyl, acetoin, acetone, and 2-butanone contribute most to the typical aroma and flavor of yogurt. Extended storage of yogurt causes off-flavor development, which is mainly attributed to the production of undesired aldehydes and fatty acids during lipid oxidation. Further work on studying the volatile flavor compounds-matrix interactions, flavor release mechanisms, and the synergistic effect of flavor compounds, and on correlating the sensory properties of yogurt with the compositions of volatile flavor compounds are needed to fully elucidate yogurt aroma and flavor.

  1. Photoaffinity-labeled Cytokinins

    PubMed Central

    Theiler, Jane B.; Leonard, Nelson J.; Schmitz, Ruth Y.; Skoog, Folke

    1976-01-01

    Two new azidopurine derivatives, 2-azido-N6-(Δ2-isopentenyl)adenine and 2-azido-N6-benzyladenine, have been synthesized as potential photoaffinity labels for probing cytokinin-binding sites. The preparation and the biological activity of these compounds are described. PMID:16659772

  2. Some statistics on intermetallic compounds.

    PubMed

    Dshemuchadse, Julia; Steurer, Walter

    2015-02-02

    It is still largely unknown why intermetallic phases show such a large variety of crystal structures, with unit cell sizes varying between 1 and more than 20 000 atoms. The goal of our study was, therefore, to get a general overview of the symmetries, unit cell sizes, stoichiometries, most frequent structure types, and their stability fields based on the Mendeleev numbers as ordering parameters. A total of 20829 structures crystallizing in 2166 structure types have been studied for this purpose. Thereby, the focus was on a subset of 6441 binary intermetallic compounds, which crystallize in 943 structure types.

  3. Volatile organic compound sensor system

    DOEpatents

    Schabron, John F [Laramie, WY; Rovani, Jr., Joseph F.; Bomstad, Theresa M [Waxahachie, TX; Sorini-Wong, Susan S [Laramie, WY; Wong, Gregory K [Laramie, WY

    2011-03-01

    Generally, this invention relates to the development of field monitoring methodology for new substances and sensing chemical warfare agents (CWAs) and terrorist substances. It also relates to a portable test kit which may be utilized to measure concentrations of halogenated volatile organic compounds (VOCs) in the field. Specifically it relates to systems for reliably field sensing the potential presence of such items while also distinguishing them from other elements potentially present. It also relates to overall systems and processes for sensing, reacting, and responding to an indicated presence of such substance, including modifications of existing halogenated sensors and arrayed sensing systems and methods.

  4. Volatile organic compound sensor system

    DOEpatents

    Schabron, John F [Laramie, WY; Rovani, Jr., Joseph F.; Bomstad, Theresa M [Laramie, WY; Sorini-Wong, Susan S [Laramie, WY

    2009-02-10

    Generally, this invention relates to the development of field monitoring methodology for new substances and sensing chemical warfare agents (CWAs) and terrorist substances. It also relates to a portable test kit which may be utilized to measure concentrations of halogenated volatile organic compounds (VOCs) in the field. Specifically it relates to systems for reliably field sensing the potential presence of such items while also distinguishing them from other elements potentially present. It also relates to overall systems and processes for sensing, reacting, and responding to an indicated presence of such substance, including modifications of existing halogenated sensors and arrayed sensing systems and methods.

  5. Structure Determination of Compound 34

    DTIC Science & Technology

    1991-09-01

    report documents the results of this study. 3. EXPERIMENTAL SECTION 3.1 Materials. The sample of Compound 34 (a purplish- blue solid) was obtained from the...resulting blue solution was applied to the plate with a capillary tube drawn to a fine point. The methods of detection included visible light...chloroform (3 by 15 mL). The chloroform solution was dried over MgS04 , filtered, and then evaporated to yield a purple/ blue oil that solidified on standing

  6. Hyperpolarizable compounds and devices fabricated therefrom

    DOEpatents

    Therien, M.J.; DiMagno, S.G.

    1998-07-21

    Substituted compounds having relatively large molecular first order hyperpolarizabilities are provided, along with devices and materials containing them. In general, the compounds bear electron-donating and electron-withdrawing chemical substituents on a polyheterocyclic core. 13 figs.

  7. Lipid encapsulated phenolic compounds by fluidization

    USDA-ARS?s Scientific Manuscript database

    Phenolic compounds exhibit antioxidant and antimicrobial activities with applications as functional food and feed additives. Ferulic acid, a phenolic compound present in grain crops and lignocellulose biomass, was encapsulated with saturated triglycerides using a laboratory fluidizer. Stability of t...

  8. Therapeutic Phytogenic Compounds for Obesity and Diabetes

    PubMed Central

    Jung, Hee Soong; Lim, Yun; Kim, Eun-Kyoung

    2014-01-01

    Natural compounds have been used to develop drugs for many decades. Vast diversities and minimum side effects make natural compounds a good source for drug development. However, the composition and concentrations of natural compounds can vary. Despite this inconsistency, half of the Food and Drug Administration (FDA)-approved pharmaceuticals are natural compounds or their derivatives. Therefore, it is essential to continuously investigate natural compounds as sources of new pharmaceuticals. This review provides comprehensive information and analysis on natural compounds from plants (phytogenic compounds) that may serve as anti-obesity and/or anti-diabetes therapeutics. Our growing understanding and further exploration of the mechanisms of action of the phytogenic compounds may afford opportunities for development of therapeutic interventions in metabolic diseases. PMID:25421245

  9. Therapeutic phytogenic compounds for obesity and diabetes.

    PubMed

    Jung, Hee Soong; Lim, Yun; Kim, Eun-Kyoung

    2014-11-21

    Natural compounds have been used to develop drugs for many decades. Vast diversities and minimum side effects make natural compounds a good source for drug development. However, the composition and concentrations of natural compounds can vary. Despite this inconsistency, half of the Food and Drug Administration (FDA)-approved pharmaceuticals are natural compounds or their derivatives. Therefore, it is essential to continuously investigate natural compounds as sources of new pharmaceuticals. This review provides comprehensive information and analysis on natural compounds from plants (phytogenic compounds) that may serve as anti-obesity and/or anti-diabetes therapeutics. Our growing understanding and further exploration of the mechanisms of action of the phytogenic compounds may afford opportunities for development of therapeutic interventions in metabolic diseases.

  10. Groundwater Dating with Atmospheric Halogenated Compounds

    USGS Publications Warehouse

    Haase, Karl B.; Busenberg, Eurybiades

    2014-01-01

    "Atmospheric environmental releases refer to the emission of stable, long-lived compounds of solely anthropogenic origin into the atmosphere and the use of the compounds to estimate dates of their incorporation into groundwater."

  11. Hyperpolarizable compounds and devices fabricated therefrom

    DOEpatents

    Therien, Michael J.; DiMagno, Stephen G.

    1998-01-01

    Substituted compounds having relatively large molecular first order hyperpolarizabilities are provided, along with devices and materials containing them. In general, the compounds bear electron-donating and electron-withdrawing chemical substituents on a polyheterocyclic core.

  12. Compound Data Mining for Drug Discovery.

    PubMed

    Bajorath, Jürgen

    2017-01-01

    In recent years, there has been unprecedented growth in compound activity data in the public domain. These compound data provide an indispensable resource for drug discovery in academic environments as well as in the pharmaceutical industry. To handle large volumes of heterogeneous and complex compound data and extract discovery-relevant knowledge from these data, advanced computational mining approaches are required. Herein, major public compound data repositories are introduced, data confidence criteria reviewed, and selected data mining approaches discussed.

  13. Two new acetylenic compounds from Asparagus officinalis.

    PubMed

    Li, Xue-Mei; Cai, Jin-Long; Wang, Wen-Xiang; Ai, Hong-Lian; Mao, Zi-Chao

    2016-01-01

    Two new acetylenic compounds, asparoffins A (1) and B (2), together with two known compounds, nyasol (3) and 3″-methoxynyasol (4), were isolated from stems of Asparagus officinalis. The structures of two new compounds were elucidated on the basis of detailed spectroscopic analyses (UV, IR, MS, 1D, and 2D NMR). All compounds were evaluated for their cytotoxicities against three human cancer cell lines.

  14. Prebiotic Evolution of Nitrogen Compounds

    NASA Technical Reports Server (NTRS)

    Arrhenius, G.

    1999-01-01

    Support from this four year grant has funded our research on two general problems. One involves attempts to model the abiotic formation of simple source compounds for functional biomolecules, their concentration from dilute state in the hydrosphere and, in several cases, surface induced reactions to form precursor monomers for bioactive end products (refs. 1-5). Because of the pervasiveness and antiquity of phosphate based biochemistry and the catalytic activity of RNA we have exploring the hypothesis of an RNA World as an early stage in the emergence of life. This concept is now rather generally considered, but has been questioned due to the earlier lack of an experimentally demonstrated successful scheme for the spontaneous formation of ribose phosphate, the key backbone molecule in RNA. That impediment has now been removed. This has been achieved by demonstrating probable sources of activated (condensed) highly soluble and strongly sorbed phosphates in nature (Refs. 1,2) and effective condensation of aldehyde phosphates to form ribose phosphate in high yield (ref.6), thereby placing the RNA World concept on a somewhat safer experimental footing. Like all work in this field these experiments are oversimplifications that largely ignore competing side reactions with other compounds expected to be present. None the less our choice of experimental conditions aim at selective processes that eliminate interfering reactions. We have also sought to narrow the credibility gap by simulating geophysically and geochemically plausible conditions surrounding the putative prebiotic reactions.

  15. Corrosion Preventive Compounds Lifetime Testing

    NASA Technical Reports Server (NTRS)

    Hale, Stephanie M.; Kammerer, Catherine C.

    2007-01-01

    Lifetime Testing of Corrosion Preventive Compounds (CPCs) was performed to quantify performance in the various environments to which the Space Shuttle Orbiter is exposed during a flight cycle. Three CPCs are approved for use on the Orbiter: HD Calcium Grease, Dinitrol AV-30, and Braycote 601 EF. These CPCs have been rigorously tested to prove that they mitigate corrosion in typical environments, but little information is available on how they perform in the unique combination of the coastal environment at the launch pad, the vacuum of low-earth orbit, and the extreme heat of reentry. Currently, there is no lifetime or reapplication schedule established for these compounds that is based on this combination of environmental conditions. Aluminum 2024 coupons were coated with the three CPCs and exposed to conditions that simulate the environments to which the Orbiter is exposed. Uncoated Aluminum 2024 coupons were exposed to the environmental conditions as a control. Visual inspection and Electro- Impedance Spectroscopy (EIS) were performed on the samples in order to determine the effectiveness of the CPCs. The samples were processed through five mission life cycles or until the visual inspection revealed the initiation of corrosion and EIS indicated severe degradation of the coating.

  16. Corrosion Preventive Compounds Lifetime Testing

    NASA Technical Reports Server (NTRS)

    Hale, Stephanie M.; Kammerer, Catherine C.; Copp, Tracy L.

    2007-01-01

    Lifetime Testing of Corrosion Preventive Compounds (CPCs) was performed to quantify performance in the various environments to which the Space Shuttle Orbiter is exposed during a flight cycle. Three CPCs are approved for use on the Orbiter: RD Calcium Grease, Dinitrol AV-30, and Braycote 601 EF. These CPCs have been rigorously tested to prove that they mitigate corrosion in typical environments, but little information is available on how they perform in the unique combination of the coastal environment at the launch pad, the vacuum of low-earth orbit, and the extreme heat of reentry. Currently, there is no lifetime or reapplication schedule established for these compounds that is based on this combination of environmental conditions. Aluminum 2024 coupons were coated with the three CPCs and exposed to conditions that simulate the environments to which the Orbiter is exposed. Uncoated Aluminum 2024 coupons were exposed to the environmental conditions as a control. Visual inspection and Electro- Impedance Spectroscopy (EIS) were performed on the samples in order to determine the effectiveness of the CPCs. The samples were processed through five mission life cycles or until the visual inspection revealed the initiation of corrosion and EIS indicated severe degradation of the coating.

  17. Compound prism design principles, I

    PubMed Central

    Hagen, Nathan; Tkaczyk, Tomasz S.

    2011-01-01

    Prisms have been needlessly neglected as components used in modern optical design. In optical throughput, stray light, flexibility, and in their ability to be used in direct-view geometry, they excel over gratings. Here we show that even their well-known weak dispersion relative to gratings has been overrated by designing doublet and double Amici direct-vision compound prisms that have 14° and 23° of dispersion across the visible spectrum, equivalent to 800 and 1300 lines/mm gratings. By taking advantage of the multiple degrees of freedom available in a compound prism design, we also show prisms whose angular dispersion shows improved linearity in wavelength. In order to achieve these designs, we exploit the well-behaved nature of prism design space to write customized algorithms that optimize directly in the nonlinear design space. Using these algorithms, we showcase a number of prism designs that illustrate a performance and flexibility that goes beyond what has often been considered possible with prisms. PMID:22423145

  18. Fiber Compounds and Human Health.

    PubMed

    Camara, Montana; Fernandez-Ruiz, Virginia; Morales, Patricia; Sanchez-Mata, Maria Cortes

    2017-01-01

    It is known that insufficient consumption of fiber in Western societies is directly linked to certain diseases. The required daily fiber intake can be obtained from foods such as fruits and vegetables, whole grains, legumes, nuts and others, or by eating foods enriched with fiber as a functional ingredient. This review studies certain fiber compounds such as oligosaccharides (namely α-galactosides and fructans), arabinoxylans and β-glucans. The European regulatory body governing nutrition and health claims aims to protect consumers' right to receive truthful information about food by verifying statements on "nutrition", "content", "health claims" and "reducing the risk of disease". Some of these foods and functional ingredients can be considered as "novel foods". This paper describes the state of the art of certain fiber compounds and their effect on human health; the different requirements for fiber components used as functional or novel food ingredients; and the response of the European authorities to the use of this ingredient and its related health claims in terms of food labelling. After EFSA approval, these claims can be used in food labelling as an added value for consumer health, which may also improve their success in the market. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  19. Antimicrobial compounds of porcine mucosa

    NASA Astrophysics Data System (ADS)

    Kotenkova, E. A.; Lukinova, E. A.; Fedulova, L. V.

    2017-09-01

    The aim of the study was to investigate porcine oral cavity mucosa (OCM), nasal cavity mucosa (NCM), rectal mucosa (RM) and tongue mucosa (TM) as sources of antimicrobial compounds. Ultrafiltrates with MW >30 kDa, MW 5-30 kDa and MW <5 kDa were obtained. All ultrafiltrates had antimicrobial activity against Escherichia coli and Proteus vulgaris. NCM ultrafiltrates revealed the highest antibacterial activity in respect to negative control: for the fraction with MW >30 kDa, the zone of microbial growth inhibition was 7.5 mm, for the MW<5 kDa fraction, it was 7 mm, and for MW 5-30 kDa fraction, it was 4.5 mm. No significant differences were found in high molecular weight proteomic profile, while qualitative and quantitative differences were observed in the medium and low molecular weight areas, especially in OCM and NCM. HPLC showed 221 tissue-specific peptides in OCM, 156 in NCM, 225 in RM, but only 5 in TM. The results observed confirmed porcine mucous tissues as a good source of antimicrobial compounds, which could be an actual alternative for reduction of microbial spoilage of foods.

  20. Semiconducting compounds and devices incorporating same

    DOEpatents

    Marks, Tobin J.; Facchetti, Antonio; Boudreault, Pierre-Luc; Miyauchi, Hiroyuki

    2016-01-19

    Disclosed are molecular and polymeric compounds having desirable properties as semiconducting materials. Such compounds can exhibit desirable electronic properties and possess processing advantages including solution-processability and/or good stability. Organic transistor and photovoltaic devices incorporating the present compounds as the active layer exhibit good device performance.

  1. Semiconducting compounds and devices incorporating same

    DOEpatents

    Marks, Tobin J; Facchetti, Antonio; Boudreault, Pierre-Luc; Miyauchi, Hiroyuki

    2014-06-17

    Disclosed are molecular and polymeric compounds having desirable properties as semiconducting materials. Such compounds can exhibit desirable electronic properties and possess processing advantages including solution-processability and/or good stability. Organic transistor and photovoltaic devices incorporating the present compounds as the active layer exhibit good device performance.

  2. Thin films of mixed metal compounds

    DOEpatents

    Mickelsen, Reid A.; Chen, Wen S.

    1985-01-01

    A compositionally uniform thin film of a mixed metal compound is formed by simultaneously evaporating a first metal compound and a second metal compound from independent sources. The mean free path between the vapor particles is reduced by a gas and the mixed vapors are deposited uniformly. The invention finds particular utility in forming thin film heterojunction solar cells.

  3. Five new bioactive compounds from Chenopodium ambrosioides.

    PubMed

    Song, Kun; Zhang, Jian; Zhang, Peng; Wang, Hong-Qing; Liu, Chao; Li, Bao-Ming; Kang, Jie; Chen, Ruo-Yun

    2015-05-01

    Five new bioactive compounds, chenopodiumamines A-D (1-4) and chenopodiumoside A (5), were isolated from the ethanol extract of Chenopodium ambrosioides. The structures of these compounds were elucidated by various spectroscopic means (UV, IR, HR-ESI-MS, 1D and 2D NMR). Compounds 1-3 had moderate antioxidant and anti-inflammatory activities.

  4. The Modification of Compounds by Attributive Adjectives

    ERIC Educational Resources Information Center

    Berg, Thomas

    2011-01-01

    This paper examines the modification of nominal compounds by attributive adjectives in English. It draws on a distinction between compound-external (i.e. syntactic) and compound-internal (i.e. morphological) modification. An analysis is presented of more than 1000 pertinent cases, which are roughly equally divided into two-, three- and four-noun…

  5. The Modification of Compounds by Attributive Adjectives

    ERIC Educational Resources Information Center

    Berg, Thomas

    2011-01-01

    This paper examines the modification of nominal compounds by attributive adjectives in English. It draws on a distinction between compound-external (i.e. syntactic) and compound-internal (i.e. morphological) modification. An analysis is presented of more than 1000 pertinent cases, which are roughly equally divided into two-, three- and four-noun…

  6. INSENSITIVE HIGH-NITROGEN COMPOUNDS

    SciTech Connect

    D. CHAVEZ; ET AL

    2001-03-01

    The conventional approach to developing energetic molecules is to chemically place one or more nitro groups onto a carbon skeleton, which is why the term ''nitration'' is synonymous to explosives preparation. The nitro group carries the oxygen that reacts with the skeletal carbon and hydrogen fuels, which in turn produces the heat and gaseous reaction products necessary for driving an explosive shock. These nitro-containing energetic molecules typically have heats of formation near zero and therefore most of the released energy is derived from the combustion process. Our investigation of the tetrazine, furazan and tetrazole ring systems has offered a different approach to explosives development, where a significant amount of the chemical potential energy is derived from their large positive heats of formation. Because these compounds often contain a large percentage of nitrogen atoms, they are usually regarded as high-nitrogen fuels or explosives. A general artifact of these high-nitrogen compounds is that they are less sensitive to initiation (e.g. by impact) when compared to traditional nitro-containing explosives of similar performances. Using the precursor, 3,6-bis-(3,5-dimethylpyrazol-1-yl)-s-tetrazine, several useful energetic compounds based on the s-tetrazine system have been synthesized and studied. Some of the first compounds are 3,6-diamino-s-tetrazine-1,4-dioxide (LAX-112) and 3,6-dihydrazino-s-tetrazine (DHT). LAX-112 was once extensively studied as an insensitive explosive by Los Alamos; DHT is an example of a high-nitrogen explosive that relies entirely on its heat of formation for sustaining a detonation. Recent synthesis efforts have yielded an azo-s-tetrazine, 3,3'-azobis(6-amino-s-tetrazine) or DAAT, which has a very high positive heat of formation. The compounds, 4,4'-diamino-3,3'-azoxyfurazan (DAAF) and 4,4'-diamino-3,3'-azofurazan (DAAzF), may have important future roles in insensitive explosive applications. Neither DAAF nor DAAzF can be

  7. Antioxidant phenolic compounds from Pu-erh tea.

    PubMed

    Zhang, Hai Ming; Wang, Cheng Fang; Shen, Sheng Min; Wang, Gang Li; Liu, Peng; Liu, Zi Mu; Wang, Yong Yan; Du, Shu Shan; Liu, Zhi Long; Deng, Zhi Wei

    2012-11-27

    Eight compounds were isolated from the water extract of Pu-erh tea and their structures were elucidated by NMR and MS as gallic acid (1), (+)-catechin (2), (−)-epicatechin (3), (−)-epicatechin-3-O-gallate (4), (−)-epigallocatechin-3-O-gallate (5), (−)-epiafzelechin- 3-O-gallate (6), kaempferol (7), and quercetin (8). Their in vitro antioxidant activities were assessed by the DPPH and ABTS scavenging methods with microplate assays. The relative order of DPPH scavenging capacity for these compounds was compound 8 > compound 7 > compound 1 > compound 6 > compound 4 ≈ compound 5 > compound 2 > VC (reference) > compound 3, and that of ABTS scavenging capacity was compound 1 > compound 2 > compound 7 ≈ compound 8 > compound 6 > compound 5 > compound 4 > VC (reference) > compound 3. The results showed that these phenolic compounds contributed to the antioxidant activity of Pu-erh tea.

  8. Method for purifying bidentate organophosphorous compounds

    DOEpatents

    McIsaac, Lyle D.; Krupa, Joseph F.; Schroeder, Norman C.

    1981-01-01

    Bidentate organophosphorous compounds are purified of undesirable impurities by contacting a solution of the compounds with a mercuric nitrate solution to form an insoluble mercuric bidentate compound which precipitates while the impurities remain in solution. The precipitate is washed and then contacted with a mixture of an aqueous solution of a strong mercuric ion complexing agent and an organic solvent to complex the mercuric ion away from the bidentate compound which then dissolves in the solvent. The purified bidentate compounds are useful for extracting the actinide elements from aqueous acidic nuclear waste solutions.

  9. Highly sweet compounds of plant origin.

    PubMed

    Kim, Nam-Cheol; Kinghorn, A Douglas

    2002-12-01

    The demand for new alternative "low calorie" sweeteners for dietetic and diabetic purposes has increased worldwide. Although the currently developed and commercially used highly sweet sucrose substitutes are mostly synthetic compounds, the search for such compounds from natural sources is continuing. As of mid-2002, over 100 plant-derived sweet compounds of 20 major structural types had been reported, and were isolated from more than 25 different families of green plants. Several of these highly sweet natural products are marketed as sweeteners or flavoring agents in some countries as pure compounds, compound mixtures, or refined extracts. These highly sweet natural substances are reviewed herein.

  10. Elastomer Compound Developed for High Wear Applications

    NASA Technical Reports Server (NTRS)

    Crawford, D.; Feuer, H.; Flanagan, D.; Rodriguez, G.; Teets, A.; Touchet, P.

    1993-01-01

    The U.S. Army is currently spending 300 million dollars per year replacing rubber track pads. An experimental rubber compound has been developed which exhibits 2 to 3 times greater service life than standard production pad compounds. To improve the service life of the tank track pads various aspects of rubber chemistry were explored including polymer, curing and reinforcing systems. Compounds that exhibited superior physical properties based on laboratory data were then fabricated into tank pads and field tested. This paper will discuss the compounding studies, laboratory data and field testing that led to the high wear elastomer compound.

  11. Veterinary Compounding: Regulation, Challenges, and Resources.

    PubMed

    Davidson, Gigi

    2017-01-10

    The spectrum of therapeutic need in veterinary medicine is large, and the availability of approved drug products for all veterinary species and indications is relatively small. For this reason, extemporaneous preparation, or compounding, of drugs is commonly employed to provide veterinary medical therapies. The scope of veterinary compounding is broad and focused primarily on meeting the therapeutic needs of companion animals and not food-producing animals in order to avoid human exposure to drug residues. As beneficial as compounded medical therapies may be to animal patients, these therapies are not without risks, and serious adverse events may occur from poor quality compounds or excipients that are uniquely toxic when administered to a given species. Other challenges in extemporaneous compounding for animals include significant regulatory variation across the global veterinary community, a relative lack of validated compounding formulas for use in animals, and poor adherence by compounders to established compounding standards. The information presented in this article is intended to provide an overview of the current landscape of compounding for animals; a discussion on associated benefits, risks, and challenges; and resources to aid compounders in preparing animal compounds of the highest possible quality.

  12. Practices of pharmacies that compound extemporaneous formulations.

    PubMed

    Treadway, Angela K; Craddock, Deeatra; Leff, Richard

    2007-07-01

    A survey was conducted to characterize the standard of practice for extemporaneous pharmaceutical compounding within community and institutional pharmacies. Extemporaneous compounding practices vary among pharmacies. Because of this, the survey inquired specifically about a single pharmaceutical product (caffeine citrate 20 mg/mL) to minimize variability among respondents. Survey questions were written to identify compounding practice variations with (1) policies and procedures, (2) process validation, (3) personnel education, training, and evaluation, (4) expiration dating, (5) storage and handling of compounded prescriptions within the pharmacy, (6) labeling, (7) facilities and equipment, (8) end-product evaluation, (9) handling of sterile products outside of the pharmacy, (10) aseptic technique and product preparation, and (11) documentation. A total of 522 surveys were mailed; 117 completed surveys were returned and included in the analyses. Over half of the pharmacies surveyed were large institutional pharmacies with daily prescriptions exceeding 300. Almost 71% of pharmacies reported having policies and procedures for compounding and providing compounding training for staff. Almost one third of the pharmacies that responded did not have compounding policies and procedures and did not provide staff training. For those pharmacies that provided training, the methods used were diverse (e.g., lectures and videotapes, external certificate programs). Formulations used to compound caffeine appeared to be diverse as evidenced by the varied addition of inactive ingredients. A survey of compounding pharmacies found variability in overall compounding practices and training and in practices specifically related to compounding preparations of caffeine citrate.

  13. Veterinary Compounding: Regulation, Challenges, and Resources

    PubMed Central

    Davidson, Gigi

    2017-01-01

    The spectrum of therapeutic need in veterinary medicine is large, and the availability of approved drug products for all veterinary species and indications is relatively small. For this reason, extemporaneous preparation, or compounding, of drugs is commonly employed to provide veterinary medical therapies. The scope of veterinary compounding is broad and focused primarily on meeting the therapeutic needs of companion animals and not food-producing animals in order to avoid human exposure to drug residues. As beneficial as compounded medical therapies may be to animal patients, these therapies are not without risks, and serious adverse events may occur from poor quality compounds or excipients that are uniquely toxic when administered to a given species. Other challenges in extemporaneous compounding for animals include significant regulatory variation across the global veterinary community, a relative lack of validated compounding formulas for use in animals, and poor adherence by compounders to established compounding standards. The information presented in this article is intended to provide an overview of the current landscape of compounding for animals; a discussion on associated benefits, risks, and challenges; and resources to aid compounders in preparing animal compounds of the highest possible quality. PMID:28075379

  14. Antimicrobial compounds from Alpinia conchigera.

    PubMed

    Aziz, Ahmad Nazif; Ibrahim, Halijah; Rosmy Syamsir, Devi; Mohtar, Mastura; Vejayan, Jaya; Awang, Khalijah

    2013-02-13

    The rhizome of Alpinia conchigerahas been used as a condiment in the northern states of Peninsular Malaysia and occasionally in folk medicine in the east coast to treat fungal infections. In some states of Peninsular Malaysia, the rhizomes are consumed as a post-partum medicine and the young shoots are prepared into a vegetable dish. This study aimed to investigate the chemical constituents of the pseudostems and rhizomes of Malaysian Alpinia conchigera and to evaluate the antimicrobial activity of the dichloromethane (DCM) extracts of the pseudostems, rhizomes and the isolated compounds against three selected fungi and five strains of Staphylococcus aureus. The dried and ground pseudostems (0.8kg) and rhizomes (1.0kg) were successively extracted in Soxhlet extractor using n-hexane, dichloromethane (DCM) and methanol. The n-hexane and DCM extracts of the pseudostem and rhizome were subjected to isolation and purification using column chromatography on silica gel using a stepwise gradient system (n-hexane to methanol). Briefly, a serial two fold dilutions of the test materials dissolved in DMSO were prepared prior to addition of 100μl overnight microbial suspension (108 cfu/ml) followed by incubation at 37°C (bacteria) or 26°C (dermatophytes and candida) for 24h. The highest concentration of DMSO remaining after dilution (5%, v/v) caused no inhibition to bacterial/candida/dermatophytes' growth. Antibiotic cycloheximide was used as reference for anticandidal and antidermatophyte comparison while oxacilin was used as reference for antibacterial testing. DMSO served as negative control. Turbidity was taken as indication of growth, thus the lowest concentration which remains clear after macroscopic evaluation was taken as the minimum inhibitory concentration (MIC). The isolation of n-hexane and DCM extracts of the rhizomes and pseudostems of Alpinia conchigera via column chromatography yielded two triterpenes isolated as a mixture of stigmasterol and

  15. Volatile organic compound sensing devices

    DOEpatents

    Lancaster, G.D.; Moore, G.A.; Stone, M.L.; Reagen, W.K.

    1995-08-29

    Apparatus employing vapochromic materials in the form of inorganic double complex salts which change color reversibly when exposed to volatile organic compound (VOC) vapors is adapted for VOC vapor detection, VOC aqueous matrix detection, and selective VOC vapor detection. The basic VOC vapochromic sensor is incorporated in various devices such as a ground probe sensor, a wristband sensor, a periodic sampling monitor, a soil/water penetrometer, an evaporative purge sensor, and various vacuum-based sensors which are particularly adapted for reversible/reusable detection, remote detection, continuous monitoring, or rapid screening of environmental remediation and waste management sites. The vapochromic sensor is used in combination with various fiber optic arrangements to provide a calibrated qualitative and/or quantitative indication of the presence of VOCs. 15 figs.

  16. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, L.A. Jr.; Arganbright, R.P.; Hearn, D.

    1993-01-05

    Aromatic compounds are alkylated in a combination reactor/distillation column comprising a vessel suitable for operating between 70 C and 500 C and from 0.5 to 20 atmospheres pressure; an inert distillation packing in the lower one-third of said vessel; solid acidic catalytic material such as zeolites or an acidic cation exchange resin supported in the middle one-third of said vessel; and inert distillation packing in the upper one-third of said vessel. A benzene inlet is located near the upper end of the vessel; an olefin inlet is juxtaposed with said solid acidic catalytic material; a bottoms outlet is positioned near the bottom of said vessel for removing said cumene and ethyl benzene; and an overhead outlet is placed at the top of said vessel for removing any unreacted benzene and olefin.

  17. Alkylation of organic aromatic compounds

    DOEpatents

    Smith, Jr., Lawrence A.; Arganbright, Robert P.; Hearn, Dennis

    1993-01-01

    Aromatic compounds are alkylated in a combination reactor/distillation column comprising a vessel suitable for operating between 70.degree. C. and 500.degree. C. and from 0.5 to 20 atmospheres pressure; an inert distillation packing in the lower one-third of said vessel; solid acidic catalytic material such as zeolites or an acidic cation exchange resin supported in the middle one-third of said vessel; and inert distillation packing in the upper one-third of said vessel. A benzene inlet is located near the upper end of the vessel; an olefin inlet is juxtaposed with said solid acidic catalytic material; a bottoms outlet is positioned near the bottom of said vessel for removing said cumene and ethyl benzene; and an overhead outlet is placed at the top of said vessel for removing any unreacted benzene and olefin.

  18. New permanent magnets; manganese compounds.

    PubMed

    Coey, J M D

    2014-02-12

    The exponential growth of maximum energy product that prevailed in the 20th century has stalled, leaving a market dominated by two permanent magnet materials, Nd2Fe14B and Ba(Sr)Fe12O19, for which the maximum theoretical energy products differ by an order of magnitude (515 kJ m(-3) and 45 kJ m(-3), respectively). Rather than seeking to improve on optimized Nd-Fe-B, it is suggested that some research efforts should be devoted to developing appropriately priced alternatives with energy products in the range 100-300 kJ m(-3). The prospects for Mn-based hard magnetic materials are discussed, based on known Mn-based compounds with the tetragonal L10 or D022 structure or the hexagonal B81 structure.

  19. METHOD OF RECOVERING URANIUM COMPOUNDS

    DOEpatents

    Poirier, R.H.

    1957-10-29

    S>The recovery of uranium compounds which have been adsorbed on anion exchange resins is discussed. The uranium and thorium-containing residues from monazite processed by alkali hydroxide are separated from solution, and leached with an alkali metal carbonate solution, whereby the uranium and thorium hydrorides are dissolved. The carbonate solution is then passed over an anion exchange resin causing the uranium to be adsorbed while the thorium remains in solution. The uranium may be recovered by contacting the uranium-holding resin with an aqueous ammonium carbonate solution whereby the uranium values are eluted from the resin and then heating the eluate whereby carbon dioxide and ammonia are given off, the pH value of the solution is lowered, and the uranium is precipitated.

  20. Organic compounds in carbonaceous meteorites.

    PubMed

    Sephton, Mark A

    2002-06-01

    The carbonaceous chondrite meteorites are fragments of asteroids that have remained relatively unprocessed since the formation of the solar system 4.6 billion years ago. These carbon-rich objects contain a variety of extraterrestrial organic molecules that constitute a record of chemical evolution prior to the origin of life. Compound classes include aliphatic hydrocarbons, aromatic hydrocarbons, amino acids, carboxylic acids, sulfonic acids, phosphonic acids, alcohols, aldehydes, ketones, sugars, amines, amides, nitrogen heterocycles, sulfur heterocycles and a relatively abundant high molecular weight macromolecular material. Structural and stable isotopic characteristics suggest that a number of environments may have contributed to the organic inventory, including interstellar space, the solar nebula and the asteroidal meteorite parent body. This review covers work published between 1950 and the present day and cites 193 references.

  1. Volatile organic compound sensing devices

    DOEpatents

    Lancaster, Gregory D.; Moore, Glenn A.; Stone, Mark L.; Reagen, William K.

    1995-01-01

    Apparatus employing vapochromic materials in the form of inorganic double complex salts which change color reversibly when exposed to volatile organic compound (VOC) vapors is adapted for VOC vapor detection, VOC aqueous matrix detection, and selective VOC vapor detection. The basic VOC vapochromic sensor is incorporated in various devices such as a ground probe sensor, a wristband sensor, a periodic sampling monitor, a soil/water penetrometer, an evaporative purge sensor, and various vacuum-based sensors which are particularly adapted for reversible/reusable detection, remote detection, continuous monitoring, or rapid screening of environmental remediation and waste management sites. The vapochromic sensor is used in combination with various fiber optic arrangements to provide a calibrated qualitative and/or quantitative indication of the presence of VOCs.

  2. Thin films of mixed metal compounds

    DOEpatents

    Mickelsen, R.A.; Chen, W.S.

    1985-06-11

    Disclosed is a thin film heterojunction solar cell, said heterojunction comprising a p-type I-III-IV[sub 2] chalcopyrite substrate and an overlying layer of an n-type ternary mixed metal compound wherein said ternary mixed metal compound is applied to said substrate by introducing the vapor of a first metal compound to a vessel containing said substrate from a first vapor source while simultaneously introducing a vapor of a second metal compound from a second vapor source of said vessel, said first and second metals comprising the metal components of said mixed metal compound; independently controlling the vaporization rate of said first and second vapor sources; reducing the mean free path between vapor particles in said vessel, said gas being present in an amount sufficient to induce homogeneity of said vapor mixture; and depositing said mixed metal compound on said substrate in the form of a uniform composition polycrystalline mixed metal compound. 5 figs.

  3. Theoretical Studies on Cluster Compounds

    NASA Astrophysics Data System (ADS)

    Lin, Zhenyang

    interconversion of conformers of these clusters are described. In Chapter 5 Stone's Tensor Surface Harmonic methodology is applied to high nuclearity transition metal carbonyl cluster compounds with 13-44 metal atoms. Chapter 6 develops a new theoretical framework to account for the bonding in the high nuclearity ligated clusters with columnar topologies. In Chapter 7 the origin of non-bonding orbitals in molecular compounds is reviewed and analysed using general quantum mechanical considerations. (Abstract shortened by UMI.).

  4. High-Strength, Superelastic Compounds

    NASA Technical Reports Server (NTRS)

    Stanford, Malcolm; Noebe, Ronald; Dellacorte, Christopher; Bigelow, Glen; Thomas, Fransua

    2013-01-01

    In a previous disclosure, the use of 60- NiTiNOL, an ordered intermetallic compound composed of 60 weight percent nickel and 40 weight percent titanium, was investigated as a material for advanced aerospace bearings due to its unique combination of physical properties. Lessons learned during the development of applications for this material have led to the discovery that, with the addition of a ternary element, the resulting material can be thermally processed at a lower temperature to attain the same desirable hardness level as the original material. Processing at a lower temperature is beneficial, not only because it reduces processing costs from energy consumption, but because it also significantly reduces the possibility of quench cracking and thermal distortion, which have been problematic with the original material. A family of ternary substitutions has been identified, including Hf and Zr in various atomic percentages with varying concentrations of Ni and Ti. In the present innovation, a ternary intermetallic compound consisting of 57.6 weight percent Ni, 39.2 weight percent Ti, and 3.2 weight percent Hf (54Ni-45Ti-1Hf atomic percent) was prepared by casting. In this material, Hf substitutes for some of the Ti atoms in the material. In an alternate embodiment of the innovation, Zr, which is close in chemical behavior to Hf, is used as the substitutional element. With either substitution, the solvus temperature of the material is reduced, and lower temperatures can be used to obtain the necessary hardness values. The advantages of this innovation include the ability to solution-treat the material at a lower temperature and still achieve the required hardness for bearings (at least 50 Rockwell C) and superelastic behavior with recoverable strains greater than 2%. Most structural alloys will not return to their original shape after being deformed as little as 0.2% (a tenth of that possible with superelastic materials like 60 NiTiNOL). Because lower temperatures

  5. White ECD using zinc compound

    NASA Astrophysics Data System (ADS)

    Kashiwazaki, Naoya; Yamana, Masao

    1999-10-01

    Adiabatic planning for building is a good idea for saving energy and favor of earth environment. Windows of housing are important for providing natural lighting and ventilation, however, they obstruct adiabatic planning. Light-controllable windows, which are called `smart windows' are of use and one solution for adiabatic planning. Smart windows can control the intensity of light as user pleases. Their driving mechanism uses some kind of chromism, thermochromism, photochromism and/or electrochromism. Electrochromic device (ECD) can control both light-holding and heat-radiation by electrochemical redox. Most ECDs using transitional metal oxide which have been studied have colored states such as blue or brown. We consider that white ECD is more suitable for living spaces. In our study, white ECD materials were developed for smart-windows by using a zinc compound. This window changes between a transparent- state and a white-state, like a Japanese-SHOJI', in response to electric conditions. This smart-window can also control light-intensity (transparency) by both applied pulse width and pulse voltage, and no power is consumed to maintain a state. A test trial device which was assembled by our project can change its states between transparency and white, in stable, during over 500 trials.

  6. Environmentally Friendly Corrosion Preventative Compounds

    NASA Technical Reports Server (NTRS)

    Calle, Luz Marina; Montgomery, Eliza; Kolody, Mark; Curran, Jerry; Back, Teddy; Balles, Angela

    2012-01-01

    The objective of the Ground Systems Development and Operations Program Environmentally Friendly Corrosion Protective Coatings and Corrosion Preventive Compounds (CPCs) project is to identify, test, and develop qualification criteria for the use of environmentally friendly corrosion protective coatings and CPCs for flight hardware and ground support equipment. This document is the Final Report for Phase I evaluations, which included physical property, corrosion resistance, and NASA spaceport environment compatibility testing and analysis of fifteen CPC types. The CPCs consisted of ten different oily film CPCs and five different wax or grease CPC types. Physical property testing encompassed measuring various properties of the bulk CPCs, while corrosion resistance testing directly measured the ability of each CPC material to protect various metals against corrosion. The NASA spaceport environment compatibility testing included common tests required by NASA-STD-6001, "Flammability, Odor, Offgassing, and Compatibility Requirements and Test Procedures for Materials in Environments that Support Combustion". At the end of Phase I, CPC materials were down-selected for inclusion in the next test phases. This final report includes all data and analysis of results obtained by following the experimental test plan that was developed as part of the project. Highlights of the results are summarized by test criteria type.

  7. MONITORING SYNTHETIC MUSK COMPOUNDS IN ...

    EPA Pesticide Factsheets

    Synthetic musk compounds are manufactured as fragrance materials for consumer products and are consumed in very large quantities worldwide. The research focused on in the subtasks is the development and application of state-of the-art technologies to meet the needs of the public, Office of Water, and ORD in the area of Water Quality. Located In the subtasks are the various research projects being performed in support of this Task and more in-depth coverage of each project. Briefly, each project's objective is stated below.Subtask 1: To integrate state-of-the-art technologies (polar organic chemical integrative samplers, advanced solid-phase extraction methodologies with liquid chromatography/electrospray/mass spectrometry) and apply them to studying the sources and fate of a select list of PPCPs. Application and improvement of analytical methodologies that can detect non-volatile, polar, water-soluble pharmaceuticals in source waters at levels that could be environmentally significant (at concentrations less than parts per billion, ppb). IAG with USGS ends in FY05. APM 20 due in FY05.Subtask 2: Coordination of interagency research and public outreach activities for PPCPs. Participate on NSTC Health and Environment subcommittee working group on PPCPs. Web site maintenance and expansion, invited technical presentations, invited articles for peer-reviewed journals, interviews for media, responding to public inquiries. Subtask 3: To apply state-of-the-art envir

  8. Heterogeneous Integration of Compound Semiconductors

    NASA Astrophysics Data System (ADS)

    Moutanabbir, Oussama; Gösele, Ulrich

    2010-08-01

    The ability to tailor compound semiconductors and to integrate them onto foreign substrates can lead to superior or novel functionalities with a potential impact on various areas in electronics, optoelectronics, spintronics, biosensing, and photovoltaics. This review provides a brief description of different approaches to achieve this heterogeneous integration, with an emphasis on the ion-cut process, also known commercially as the Smart-Cut™ process. This process combines semiconductor wafer bonding and undercutting using defect engineering by light ion implantation. Bulk-quality heterostructures frequently unattainable by direct epitaxial growth can be produced, provided that a list of technical criteria is fulfilled, thus offering an additional degree of freedom in the design and fabrication of heterogeneous and flexible devices. Ion cutting is a generic process that can be employed to split and transfer fine monocrystalline layers from various crystals. Materials and engineering issues as well as our current understanding of the underlying physics involved in its application to cleaving thin layers from freestanding GaN, InP, and GaAs wafers are presented.

  9. Bioactive Compounds from Vitex leptobotrys#

    PubMed Central

    Pan, Wenhui; Liu, Kanglun; Guan, Yifu; Tan, Ghee Teng; Hung, Nguyen Van; Cuong, Nguyen Manh; Soejarto, D. Doel; Pezzuto, John M.; Fong, Harry H.S.; Zhang, Hongjie

    2014-01-01

    A new lignan, vitexkarinol (1), as well as a known lignan, neopaulownin (2), a known chalcone, 3-(4-hydroxyphenyl)-1-(2,4,6-trimethoxyphenyl)-2-propen-1-one (3), two known dehydroflavones, tsugafolin (4) and alpinetin (5), two known dipeptides, aurantiamide and aurantiamide acetate, a known sesquiterpene, vemopolyanthofuran, and five known carotenoid metabolites, vomifoliol, dihydrovomifoliol, dehydrovomifoliol, loliolide and isololiolide, were isolated from the leaves and twigs of Vitex leptobotrys through bioassay-guided fractionation. The chalcone (3) was found to inhibit HIV-1 replication by 77% at 15.9 µM, and the two dehydroflavones (4 and 5) showed weak anti-HIV activity with IC50 values of 118 and 130 µM, respectively, while being devoid of cytotoxicity at 150 µM. A chlorophyll-enriched fraction of V. leptobotrys, containing pheophorbide a, was found to inhibit the replication of HIV-1 by 80% at a concentration of 10 µg/mL. Compounds 1 and 3 were further selected to be evaluated against 21 viral targets available at NIAID (National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD). PMID:24404757

  10. Superconducting compounds and alloys research

    NASA Technical Reports Server (NTRS)

    Otto, G.

    1975-01-01

    Resistivity measurements as a function of temperature were performed on alloys of the binary material system In sub(1-x) Bi sub x for x varying between 0 and 1. It was found that for all single-phase alloys (the pure elements, alpha-In, and the three intermetallic compounds) at temperatures sufficiently above the Debye-temperature, the resistivity p can be expressed as p = a sub o T(n), where a sub o and n are composition-dependent constants. The same exponential relationship can also be applied for the sub-system In-In2Bi, when the two phases are in compositional equilibrium. Superconductivity measurements on single and two-phase alloys can be explained with respect to the phase diagram. There occur three superconducting phases (alpha-In, In2Bi, and In5Bi3) with different transition temperatures in the alloying system. The magnitude of the transition temperatures for the various intermetallic phases of In-Bi is such that the disappearance or occurrence of a phase in two component alloys can be demonstrated easily by means of superconductivity measurements.

  11. Compound semiconductor surfaces and interfaces

    NASA Astrophysics Data System (ADS)

    Wilmsen, C. W.

    All semiconductor devices and integrated circuits require dielectric layers for interconnect isolation, gate oxides, passivation, etc. Thermally grown SiO2 is the primary dielectric film for silicon technology. This ONR contract investigated the chemistry and electrical properties of the interface between III-V compound semiconductors and electrical properties of grown and deposited oxides. When this study began, very little was known about these oxides or their interfaces. The results of the research supported by this contract has added substantially to the fundamental understanding of the oxide growth, properties and electronic structure. Much of the experimental work was obtained with surface analytical techniques and significant contributions were also made in this field. The original ONR contract began in October 1975 and initially concentrated on the grown oxides of InP and GaAs. This work evolved over the years to include the study of deposited insulator/InP interfaces and trapping at the interface. The ONR contract has supported the publication of 31 journal articles and book chapters and numerous conference presentations.

  12. Organic electronic devices using phthalimide compounds

    DOEpatents

    Hassan, Azad M.; Thompson, Mark E.

    2010-09-07

    Organic electronic devices comprising a phthalimide compound. The phthalimide compounds disclosed herein are electron transporters with large HOMO-LUMO gaps, high triplet energies, large reduction potentials, and/or thermal and chemical stability. As such, these phthalimide compounds are suitable for use in any of various organic electronic devices, such as OLEDs and solar cells. In an OLED, the phthalimide compounds may serve various functions, such as a host in the emissive layer, as a hole blocking material, or as an electron transport material. In a solar cell, the phthalimide compounds may serve various functions, such as an exciton blocking material. Various examples of phthalimide compounds which may be suitable for use in the present invention are disclosed.

  13. Organic electronic devices using phthalimide compounds

    DOEpatents

    Hassan, Azad M.; Thompson, Mark E.

    2013-03-19

    Organic electronic devices comprising a phthalimide compound. The phthalimide compounds disclosed herein are electron transporters with large HOMO-LUMO gaps, high triplet energies, large reduction potentials, and/or thermal and chemical stability. As such, these phthalimide compounds are suitable for use in any of various organic electronic devices, such as OLEDs and solar cells. In an OLED, the phthalimide compounds may serve various functions, such as a host in the emissive layer, as a hole blocking material, or as an electron transport material. In a solar cell, the phthalimide compounds may serve various functions, such as an exciton blocking material. Various examples of phthalimide compounds which may be suitable for use in the present invention are disclosed.

  14. Organic electronic devices using phthalimide compounds

    DOEpatents

    Hassan, Azad M.; Thompson, Mark E.

    2012-10-23

    Organic electronic devices comprising a phthalimide compound. The phthalimide compounds disclosed herein are electron transporters with large HOMO-LUMO gaps, high triplet energies, large reduction potentials, and/or thermal and chemical stability. As such, these phthalimide compounds are suitable for use in any of various organic electronic devices, such as OLEDs and solar cells. In an OLED, the phthalimide compounds may serve various functions, such as a host in the emissive layer, as a hole blocking material, or as an electron transport material. In a solar cell, the phthalimide compounds may serve various functions, such as an exciton blocking material. Various examples of phthalimide compounds which may be suitable for use in the present invention are disclosed.

  15. Antibacterial and Antifungal Compounds from Marine Fungi

    PubMed Central

    Xu, Lijian; Meng, Wei; Cao, Cong; Wang, Jian; Shan, Wenjun; Wang, Qinggui

    2015-01-01

    This paper reviews 116 new compounds with antifungal or antibacterial activities as well as 169 other known antimicrobial compounds, with a specific focus on January 2010 through March 2015. Furthermore, the phylogeny of the fungi producing these antibacterial or antifungal compounds was analyzed. The new methods used to isolate marine fungi that possess antibacterial or antifungal activities as well as the relationship between structure and activity are shown in this review. PMID:26042616

  16. Antibacterial and antifungal compounds from marine fungi.

    PubMed

    Xu, Lijian; Meng, Wei; Cao, Cong; Wang, Jian; Shan, Wenjun; Wang, Qinggui

    2015-06-02

    This paper reviews 116 new compounds with antifungal or antibacterial activities as well as 169 other known antimicrobial compounds, with a specific focus on January 2010 through March 2015. Furthermore, the phylogeny of the fungi producing these antibacterial or antifungal compounds was analyzed. The new methods used to isolate marine fungi that possess antibacterial or antifungal activities as well as the relationship between structure and activity are shown in this review.

  17. Complex fragment emission from hot compound nuclei

    SciTech Connect

    Moretto, L.G.

    1986-03-01

    The experimental evidence for compound nucleus emission of complex fragments at low energies is used to interpret the emission of the same fragments at higher energies. The resulting experimental picture is that of highly excited compound nuclei formed in incomplete fusion processes which decay statistically. In particular, complex fragments appear to be produced mostly through compound nucleus decay. In the appendix a geometric-kinematic theory for incomplete fusion and the associated momentum transfer is outlined. 10 refs., 19 figs.

  18. High performance compound semiconductor SPAD arrays

    NASA Astrophysics Data System (ADS)

    Harmon, Eric S.; Naydenkov, Mikhail; Bowling, Jared

    2016-05-01

    Aggregated compound semiconductor single photon avalanche diode (SPAD) arrays are emerging as a viable alternative to the silicon photomultiplier (SiPM). Compound semiconductors have the potential to surpass SiPM performance, potentially achieving orders of magnitude lower dark count rates and improved radiation hardness. New planar processing techniques have been developed to enable compound semiconductor SPAD devices to be produced with pixel pitches of 11 - 25 microns, with thousands of SPADs per array.

  19. Thread-compound test procedures being developed

    SciTech Connect

    Wood, F.; Dairymple, D. ); McKown, K.; Matthews, B. )

    1990-09-10

    API is planning to issue a new bulletin that will outline standardization test procedures and set minimum performance for thread compounds used on OCTG (oil country tubular goods) connections with API thread forms. These performance standards will replace the recommended compound described in API Bulletin 5A2. This paper discusses how the proposed bulletin will detail test equipment, procedures, and performance requirements for thread compounds.

  20. Response of Bioluminescent Bacteria to Alkyltin Compounds.

    DTIC Science & Technology

    1987-12-01

    found in the butyltiri series of compounds; tributyltin was (’Stimes more toxic than dibutyltin and (- 50 times more toxic than (mono)butyltin. When...correlations between compounds, tributyltin was -35 tine more Kicrotxit and fish bLoessays for pure toxic than dibutyltin end -750 times More compounds and...alkyltin " trihalides. Figure 4. Mo values for butyltin tri- D~kyflS chloride, dibutyltin dichloride tributyl- tin chloride and tatrabutyltin. Figures 5, 6

  1. Oxygen stabilized zirconium vanadium intermetallic compound

    DOEpatents

    Mendelsohn, Marshall H.; Gruen, Dieter M.

    1982-01-01

    An oxygen stabilized intermetallic compound having the formula Zr.sub.x OV.sub.y where x=0.7 to 2.0 and y=0.18 to 0.33. The compound is capable of reversibly sorbing hydrogen at temperatures from -196.degree. C. to 450.degree. C. at pressures down to 10.sup.-6 Torr. The compound is also capable of selectively sorbing hydrogen from gaseous mixtures in the presence of CO and CO.sub.2.

  2. Computed structures of polyimides model compounds

    NASA Technical Reports Server (NTRS)

    Tai, H.; Phillips, D. H.

    1990-01-01

    Using a semi-empirical approach, a computer study was made of 8 model compounds of polyimides. The compounds represent subunits from which NASA Langley Research Center has successfully synthesized polymers for aerospace high performance material application, including one of the most promising, LARC-TPI polymer. Three-dimensional graphic display as well as important molecular structure data pertaining to these 8 compounds are obtained.

  3. Statistical Theory of Compound-Nuclear Reactions

    SciTech Connect

    Weidenmueller, H. A.

    2008-04-17

    The Hauser-Feshbach formula for the average compound-nucleus cross section formalizes Bohr's hypothesis of the independence of formation and decay of the compound nucleus. The statistical theory of compound-nuclear reactions aims at establishing the domain and limits of applicability of that formula and of Ericson's model for statistical cross section fluctuations using random-matrix theory as a starting point. I discuss the present status of that program, including the treatment of direct reactions.

  4. PLUTONIUM COMPOUNDS AND PROCESS FOR THEIR PREPARATION

    DOEpatents

    Wolter, F.J.; Diehl, H.C. Jr.

    1958-01-01

    This patent relates to certain new compounds of plutonium, and to the utilization of these compounds to effect purification or separation of the plutonium. The compounds are organic chelate compounds consisting of tetravalent plutonium together with a di(salicylal) alkylenediimine. These chelates are soluble in various organic solvents, but not in water. Use is made of this property in extracting the plutonium by contacting an aqueous solution thereof with an organic solution of the diimine. The plutonium is chelated, extracted and effectively separated from any impurities accompaying it in the aqueous phase.

  5. Marine bacterial sources of bioactive compounds.

    PubMed

    Jaiganesh, R; Sampath Kumar, N S

    2012-01-01

    Thousands of novel compounds have been isolated from various marine bacteria and tested for pharmacological properties, many of which are commercially available. Many more are being tested as potential bioactive compound at the preclinical and clinical stages. The growing interest in marine-derived antiviral compounds, along with the development of new technology in marine cultures and extraction, will significantly expedite the current exploration of the marine environment for compounds with significant pharmacological applications, which will continue to be a promising strategy and new trend for modern medicine. Marine actinomycetes and cyanobacteria are a prolific but underexploited source for the discovery of novel secondary metabolites.

  6. Hydrodesulfurization catalyst by Chevrel phase compounds

    DOEpatents

    McCarty, K.F.; Schrader, G.L.

    1985-05-20

    A process is disclosed for the hydrodesulfurization of sulfur-containing hydrocarbon fuel with reduced ternary molybdenum sulfides, known as Chevrel phase compounds. Chevrel phase compounds of the general composition M/sub x/Mo/sub 6/S/sub 8/, with M being Ho, Pb, Sn, Ag, In, Cu, Fe, Ni, or Co, were found to have hydrodesulfurization activities comparable to model unpromoted and cobalt-promoted MoS/sub 2/ catalysts. The most active catalysts were the ''large'' cation compounds (Ho, Pb, Sn), and the least active catalysts were the ''small'' cation compounds (Cu, Fe, Ni, Co.).

  7. Hydrodesulfurization catalysis by Chevrel phase compounds

    DOEpatents

    McCarty, Kevin F.; Schrader, Glenn L.

    1985-12-24

    A process is disclosed for the hydrodesulfurization of sulfur-containing hydrocarbon fuel with reduced ternary molybdenum sulfides, known as Chevrel phase compounds. Chevrel phase compounds of the general composition M.sub.x Mo.sub.6 S.sub.8, with M being Ho, Pb, Sn, Ag, In, Cu, Fe, Ni, or Co, were found to have hydrodesulfurization activities comparable to model unpromoted and cobalt-promoted MoS.sub.2 catalysts. The most active catalysts were the "large" cation compounds (Ho, Pb, Sn), and the least active catalysts were the "small" cation compounds (Cu, Fe, Ni, Co.).

  8. Antimicrobial Action of Compounds from Marine Seaweed.

    PubMed

    Pérez, María José; Falqué, Elena; Domínguez, Herminia

    2016-03-09

    Seaweed produces metabolites aiding in the protection against different environmental stresses. These compounds show antiviral, antiprotozoal, antifungal, and antibacterial properties. Macroalgae can be cultured in high volumes and would represent an attractive source of potential compounds useful for unconventional drugs able to control new diseases or multiresistant strains of pathogenic microorganisms. The substances isolated from green, brown and red algae showing potent antimicrobial activity belong to polysaccharides, fatty acids, phlorotannins, pigments, lectins, alkaloids, terpenoids and halogenated compounds. This review presents the major compounds found in macroalga showing antimicrobial activities and their most promising applications.

  9. Four new compounds from Imperata cylindrica.

    PubMed

    Liu, Xuan; Zhang, Bin-Feng; Yang, Li; Chou, Gui-Xin; Wang, Zheng-Tao

    2014-04-01

    Four new compounds, impecylone (1), deacetylimpecyloside (2), seguinoside K 4-methylether (3) and impecylenolide (4), were isolated from Imperata cylindrica along with two known compounds, impecyloside (5) and seguinoside K (6). Their structures were elucidated mainly by spectroscopic analyses including 1D- and 2D-NMR techniques, and the absolute configuration of 1 was confirmed by X-ray diffraction analysis. In calcium assay, the result indicated that compounds 1, 2, 4 and 5 cannot obviously inhibit the calcium peak value compared with the negative control, and suggested that the four compounds could not have anti-inflammatory activity.

  10. Neurotoxicity of fragrance compounds: A review.

    PubMed

    Pinkas, Adi; Gonçalves, Cinara Ludvig; Aschner, Michael

    2017-10-01

    Fragrance compounds are chemicals belonging to one of several families, which are used frequently and globally in cosmetics, household products, foods and beverages. A complete list of such compounds is rarely found on the ingredients-list of such products, as "fragrance mixtures" are defined as "trade secrets" and thus protected by law. While some information regarding the general toxicity of some of these compounds is available, their neurotoxicity is known to a lesser extent. Here, we discuss the prevalence and neurotoxicity of fragrance compounds belonging to the three most common groups: phthalates, synthetic musks and chemical sensitizers. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Automated compound classification using a chemical ontology

    PubMed Central

    2012-01-01

    Background Classification of chemical compounds into compound classes by using structure derived descriptors is a well-established method to aid the evaluation and abstraction of compound properties in chemical compound databases. MeSH and recently ChEBI are examples of chemical ontologies that provide a hierarchical classification of compounds into general compound classes of biological interest based on their structural as well as property or use features. In these ontologies, compounds have been assigned manually to their respective classes. However, with the ever increasing possibilities to extract new compounds from text documents using name-to-structure tools and considering the large number of compounds deposited in databases, automated and comprehensive chemical classification methods are needed to avoid the error prone and time consuming manual classification of compounds. Results In the present work we implement principles and methods to construct a chemical ontology of classes that shall support the automated, high-quality compound classification in chemical databases or text documents. While SMARTS expressions have already been used to define chemical structure class concepts, in the present work we have extended the expressive power of such class definitions by expanding their structure-based reasoning logic. Thus, to achieve the required precision and granularity of chemical class definitions, sets of SMARTS class definitions are connected by OR and NOT logical operators. In addition, AND logic has been implemented to allow the concomitant use of flexible atom lists and stereochemistry definitions. The resulting chemical ontology is a multi-hierarchical taxonomy of concept nodes connected by directed, transitive relationships. Conclusions A proposal for a rule based definition of chemical classes has been made that allows to define chemical compound classes more precisely than before. The proposed structure-based reasoning logic allows to translate

  12. Antimicrobial Action of Compounds from Marine Seaweed

    PubMed Central

    Pérez, María José; Falqué, Elena; Domínguez, Herminia

    2016-01-01

    Seaweed produces metabolites aiding in the protection against different environmental stresses. These compounds show antiviral, antiprotozoal, antifungal, and antibacterial properties. Macroalgae can be cultured in high volumes and would represent an attractive source of potential compounds useful for unconventional drugs able to control new diseases or multiresistant strains of pathogenic microorganisms. The substances isolated from green, brown and red algae showing potent antimicrobial activity belong to polysaccharides, fatty acids, phlorotannins, pigments, lectins, alkaloids, terpenoids and halogenated compounds. This review presents the major compounds found in macroalga showing antimicrobial activities and their most promising applications. PMID:27005637

  13. INVESTIGATION OF A COMPOUND REPORTED AS BOTH FERRIMAGNETIC AND FERROELECTRIC,

    DTIC Science & Technology

    FERRITES , *FERROELECTRIC CRYSTALS, MAGNETIC PROPERTIES, X RAY DIFFRACTION, IMPURITIES, FERROELECTRICITY, FERROMAGNETISM, CRYSTAL STRUCTURE...DIELECTRIC PROPERTIES, MICROSCOPY, BARIUM COMPOUNDS, SAMARIUM COMPOUNDS, NIOBIUM COMPOUNDS, TITANIUM COMPOUNDS, TITANATES, PHOTOMICROGRAPHY, CRYSTAL LATTICES, OXIDES.

  14. Prioritizing pesticide compounds for analytical methods development

    USGS Publications Warehouse

    Norman, Julia E.; Kuivila, Kathryn; Nowell, Lisa H.

    2012-01-01

    The U.S. Geological Survey (USGS) has a periodic need to re-evaluate pesticide compounds in terms of priorities for inclusion in monitoring and studies and, thus, must also assess the current analytical capabilities for pesticide detection. To meet this need, a strategy has been developed to prioritize pesticides and degradates for analytical methods development. Screening procedures were developed to separately prioritize pesticide compounds in water and sediment. The procedures evaluate pesticide compounds in existing USGS analytical methods for water and sediment and compounds for which recent agricultural-use information was available. Measured occurrence (detection frequency and concentrations) in water and sediment, predicted concentrations in water and predicted likelihood of occurrence in sediment, potential toxicity to aquatic life or humans, and priorities of other agencies or organizations, regulatory or otherwise, were considered. Several existing strategies for prioritizing chemicals for various purposes were reviewed, including those that identify and prioritize persistent, bioaccumulative, and toxic compounds, and those that determine candidates for future regulation of drinking-water contaminants. The systematic procedures developed and used in this study rely on concepts common to many previously established strategies. The evaluation of pesticide compounds resulted in the classification of compounds into three groups: Tier 1 for high priority compounds, Tier 2 for moderate priority compounds, and Tier 3 for low priority compounds. For water, a total of 247 pesticide compounds were classified as Tier 1 and, thus, are high priority for inclusion in analytical methods for monitoring and studies. Of these, about three-quarters are included in some USGS analytical method; however, many of these compounds are included on research methods that are expensive and for which there are few data on environmental samples. The remaining quarter of Tier 1

  15. A[subscript 2]: Element or Compound?

    ERIC Educational Resources Information Center

    Stains, Marilyne; Talanquer, Vicente

    2007-01-01

    Particulate questions were used to investigate the strength of the mental association between the concept of compound and microscopic representations of molecules in students with different levels of chemistry preparation. The results have suggested that the mental association between the concepts of compound and particulate representations of…

  16. VOLATILE ORGANIC COMPOUNDS (VOCS) CHAPTER 31.

    EPA Science Inventory

    The term "volatile organic compounds' (VOCs) was originally coined to refer, as a class, to carbon-containing chemicals that participate in photochemical reactions in the ambient (outdoor) are. The regulatory definition of VOCs used by the U.S. EPA is: Any compound of carbon, ex...

  17. Semantics vs Pragmatics of a Compound Word

    ERIC Educational Resources Information Center

    Smirnova, Elena A.; Biktemirova, Ella I.; Davletbaeva, Diana N.

    2016-01-01

    This paper is devoted to the study of correlation between semantic and pragmatic potential of a compound word, which functions in informal speech, and the mechanisms of secondary nomination, which realizes the potential of semantic-pragmatic features of colloquial compounds. The relevance and the choice of the research question is based on the…

  18. Two new compounds from Ganoderma lucidum.

    PubMed

    Wang, Xin-Fang; Yan, Yong-Ming; Wang, Xin-Long; Ma, Xiu-Jing; Fu, Xue-Yan; Cheng, Yong-Xian

    2015-01-01

    Two pairs of new enantiomers, lucidulactones A and B (1 and 2), and two known compounds were isolated from Ganoderma lucidum. Their structures were determined by means of spectroscopic methods. The chiral HPLC was used to separate the ( - )- and (+)-antipodes of the new compounds.

  19. [Organisms producing hypolipidemic compounds with antioxidant activity].

    PubMed

    Puzhevskaia, T O; Grammatikova, N E; Bibikova, M V; Katlinskiĭ, A V

    2009-01-01

    Complex compounds produced by fungal cultures of Lecanicilium and Beauveria with both high hypolipidemic and antioxydant activities were screened. Two fractions of the hypolipipidemic compounds with antioxidant activity of 95 and 75% in a dose of 25 mcg/ml were isolated.

  20. Hybrid Compounding in New Zealand English

    ERIC Educational Resources Information Center

    Degani, Marta; Onysko, Alexander

    2010-01-01

    This study investigates hybrid compound formation of Maori and English terms in present day New Zealand English (NZE). On the background of Maori and English language contact, the phenomenon of hybrid compounding emerges as a process that, on the one hand, symbolizes the vitality of the Maori element in NZE and, on the other hand, marks the…

  1. Heterogeneous photocatalytic reactions of sulfur aromatic compounds.

    PubMed

    Samokhvalov, Alexander

    2011-11-18

    Sulfur aromatic compounds, such as mono-, di-, tri-, and tetraalkyl-substituted thiophene, benzothiophenes, dibenzothiophenes, are the molecular components of many fossils (petroleum, oil shale, tar sands, bitumen). Structural units of natural, cross-linked heteroaromatic polymers present in brown coals, turf, and soil are similar to those of sulfur aromatic compounds. Many sulfur aromatic compounds are found in the streams of petroleum refining and upgrading (naphthas, gas oils) and in the consumer products (gasoline, diesel, jet fuels, heating fuels). Besides fossils, the structural fragments of sulfur aromatic compounds are present in molecules of certain organic semiconductors, pesticides, small molecule drugs, and in certain biomolecules present in human body (pheomelanin pigments). Photocatalysis is the frontier area of physical chemistry that studies chemical reactions initiated by absorption of photons by photocatalysts, that is, upon electronic rather than thermal activation, under "green" ambient conditions. This review provides systematization and critical review of the fundamental chemical and physicochemical information on heterogeneous photocatalysis of sulfur aromatic compounds accumulated in the last 20-30 years. Specifically, the following topics are covered: physicochemical properties of sulfur aromatic compounds, major classes of heterogeneous photocatalysts, mechanisms and reactive intermediates of photocatalytic reactions of sulfur aromatic compounds, and the selectivity of these reactions. Quantum chemical calculations of properties and structures of sulfur aromatic compounds, their reactive intermediates, and the structure of adsorption complexes formed on the surface of the photocatalysts are also discussed.

  2. Phenolic compounds of three unconventional Sudanese oils.

    PubMed

    Mariod, Abdalbasit; Matthäus, Bertrand; Eichner, Karl; Hussein, Ismail H

    2015-01-01

    The total amount and content of phenolic and flavonoid compounds using the Folin-Ciocalteu and Aluminum chloride methods of the methanolic extracts of Sclerocarya birrea oil (SCO), Melon bug oil (MBO), and Sorghum bug oil (SBO) were studied. Dry samples of Sclerocarya birrea, Aspongopus vidiuatus and Agonoscelis pubescens were used in this study. The oil was extracted using n-hexane following AOCS method. The phenolic compounds were extracted following a well known method and the total amounts of phenolic and flavonoids were determined using Folin-Ciocalteau and aluminum chloride methods, respectively and were identified by HPLC. The concentration of total phenolic compounds was determined as 3.3, 20.7 and 0.9 mg/100 g oil, in SCO, MBO and SBO, respectively, calculated as gallic acid equivalents. The polar fraction of the three oils was separated using solid phase extraction method. The variation of simple and complex oils phenols studied by high-performance liquid chromatography with diode-array detection (DAD) using sephadex eluted by acetone revealed six phenolic compounds which were identified as vanillic acid, callistephin, sinapic acid, t-cinnamic acid, epicatechin, and luteolin in SCO, and four phenolic compounds were identified as vanillin, sinapic acid, o-coumaric acid, and quercetin, in SBO, while in MBO four phenolic compounds were identified as t-cinnamic, syringic acid, quercetin and pelargonin. The phenolic compounds found in SCO, SBO, and MBO can be divided into phenolic compounds and flavonoids.

  3. Perfluorinated Compounds: Emerging POPs with Potential Immunotoxicity

    EPA Science Inventory

    Perfluorinated compounds (PFCs) have been recognized as an important class of environmental contaminants commonly detected in blood samples of both wildlife and humans. These compounds have been in use for more than 60 years as surface treatment chemicals, polymerization aids, an...

  4. Nitroaromatic Compounds, from Synthesis to Biodegradation

    PubMed Central

    Ju, Kou-San; Parales, Rebecca E.

    2010-01-01

    Summary: Nitroaromatic compounds are relatively rare in nature and have been introduced into the environment mainly by human activities. This important class of industrial chemicals is widely used in the synthesis of many diverse products, including dyes, polymers, pesticides, and explosives. Unfortunately, their extensive use has led to environmental contamination of soil and groundwater. The nitro group, which provides chemical and functional diversity in these molecules, also contributes to the recalcitrance of these compounds to biodegradation. The electron-withdrawing nature of the nitro group, in concert with the stability of the benzene ring, makes nitroaromatic compounds resistant to oxidative degradation. Recalcitrance is further compounded by their acute toxicity, mutagenicity, and easy reduction into carcinogenic aromatic amines. Nitroaromatic compounds are hazardous to human health and are registered on the U.S. Environmental Protection Agency's list of priority pollutants for environmental remediation. Although the majority of these compounds are synthetic in nature, microorganisms in contaminated environments have rapidly adapted to their presence by evolving new biodegradation pathways that take advantage of them as sources of carbon, nitrogen, and energy. This review provides an overview of the synthesis of both man-made and biogenic nitroaromatic compounds, the bacteria that have been identified to grow on and completely mineralize nitroaromatic compounds, and the pathways that are present in these strains. The possible evolutionary origins of the newly evolved pathways are also discussed. PMID:20508249

  5. Compounds from the roots of Jasminum sambac.

    PubMed

    Zeng, Lin-Hong; Hu, Min; Yan, Yong-Ming; Lu, Qing; Cheng, Yong-Xian

    2012-01-01

    Four new compounds (+)-jasminoids A, B, C, and D, together with seven known compounds, were isolated from the roots of Jasminum sambac. Their structures were identified using spectroscopic methods. This study provides a better understanding to the chemical composition of J. sambac roots that have been thought to be one ingredient of an ancient prescription 'Ma-Fei-San'.

  6. Study of Compounds for Activity against Leishmania

    DTIC Science & Technology

    1994-03-27

    Comparative Antileishmanial Activity of Selected Compounds Against Leishmania Leishmania donovani and Leishmania Viannia braziliensis 7 IV. Zn vitro...Studies of Oligonucleotides Against Leishmania Leishmania donovani ............................................................ 9 Discussion...for several years in studies to identify new compounds for antileishmanial activity against both visceral (Lelshmania Leishmania donovani ) and

  7. Perfluorinated Compounds: Emerging POPs with Potential Immunotoxicity

    EPA Science Inventory

    Perfluorinated compounds (PFCs) have been recognized as an important class of environmental contaminants commonly detected in blood samples of both wildlife and humans. These compounds have been in use for more than 60 years as surface treatment chemicals, polymerization aids, an...

  8. Amino acid modifiers in guayule rubber compounds

    USDA-ARS?s Scientific Manuscript database

    Tire producers are increasingly interested in biobased materials, including rubber but also as compounding chemicals. An alternative natural rubber for tire use is produced by guayule, a woody desert shrub native to North America. Alternative compounding chemicals include naturally-occurring amino a...

  9. Nitroaromatic compounds, from synthesis to biodegradation.

    PubMed

    Ju, Kou-San; Parales, Rebecca E

    2010-06-01

    Nitroaromatic compounds are relatively rare in nature and have been introduced into the environment mainly by human activities. This important class of industrial chemicals is widely used in the synthesis of many diverse products, including dyes, polymers, pesticides, and explosives. Unfortunately, their extensive use has led to environmental contamination of soil and groundwater. The nitro group, which provides chemical and functional diversity in these molecules, also contributes to the recalcitrance of these compounds to biodegradation. The electron-withdrawing nature of the nitro group, in concert with the stability of the benzene ring, makes nitroaromatic compounds resistant to oxidative degradation. Recalcitrance is further compounded by their acute toxicity, mutagenicity, and easy reduction into carcinogenic aromatic amines. Nitroaromatic compounds are hazardous to human health and are registered on the U.S. Environmental Protection Agency's list of priority pollutants for environmental remediation. Although the majority of these compounds are synthetic in nature, microorganisms in contaminated environments have rapidly adapted to their presence by evolving new biodegradation pathways that take advantage of them as sources of carbon, nitrogen, and energy. This review provides an overview of the synthesis of both man-made and biogenic nitroaromatic compounds, the bacteria that have been identified to grow on and completely mineralize nitroaromatic compounds, and the pathways that are present in these strains. The possible evolutionary origins of the newly evolved pathways are also discussed.

  10. Hybrid Compounding in New Zealand English

    ERIC Educational Resources Information Center

    Degani, Marta; Onysko, Alexander

    2010-01-01

    This study investigates hybrid compound formation of Maori and English terms in present day New Zealand English (NZE). On the background of Maori and English language contact, the phenomenon of hybrid compounding emerges as a process that, on the one hand, symbolizes the vitality of the Maori element in NZE and, on the other hand, marks the…

  11. (CHINA) PERFLUORINATED ORGANIC COMPOUND EXPOSURE ASSESSMENT RESEARCH

    EPA Science Inventory

    A wide range of perfluorinated organic compounds (PFCs) has been used in a variety of industrial processes and consumer products. The most commonly studied PFCs include perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), but there are many more compounds in this c...

  12. PERFLUORINATED ORGANIC COMPOUND EXPOSURE ASSESSMENT RESEARCH

    EPA Science Inventory

    A wide range of perfluorinated organic compounds (PFCs) has been used in a variety of industrial processes and consumer products. The most commonly studied PFCs include perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), but there are many more compounds in this c...

  13. Crystal structure analysis of intermetallic compounds

    NASA Technical Reports Server (NTRS)

    Conner, R. A., Jr.; Downey, J. W.; Dwight, A. E.

    1968-01-01

    Study concerns crystal structures and lattice parameters for a number of new intermetallic compounds. Crystal structure data have been collected on equiatomic compounds, formed between an element of the Sc, Ti, V, or Cr group and an element of the Co or Ni group. The data, obtained by conventional methods, are presented in an easily usable tabular form.

  14. Improved process for synthesizing anilinosilane compounds

    NASA Technical Reports Server (NTRS)

    Dunnavant, W. R.; Markle, R. A.

    1970-01-01

    New process gives good yields of anilinosilane compounds that can be readily isolated in a high state of purity. S-collidine is used as an HCl acceptor. Silane compounds can be melt-condensed with aromatic diols to provide high molecular weight polyaryloxysilane materials that are of importance in polymer technology.

  15. Analysis of phenolic compounds for poultry feeds

    USDA-ARS?s Scientific Manuscript database

    Phenolic compounds have generated significant interest recently as feed additives that can impart bioactive characteristics such as anti-oxidant, anti-microbial, and anti-fungal properties to a feed formulation [1-2]. Such natural compounds may offer some preventive benefit to the routine administra...

  16. A[subscript 2]: Element or Compound?

    ERIC Educational Resources Information Center

    Stains, Marilyne; Talanquer, Vicente

    2007-01-01

    Particulate questions were used to investigate the strength of the mental association between the concept of compound and microscopic representations of molecules in students with different levels of chemistry preparation. The results have suggested that the mental association between the concepts of compound and particulate representations of…

  17. Ambient Air Monitoring for Sulfur Compounds

    ERIC Educational Resources Information Center

    Forrest, Joseph; Newman, Leonard

    1973-01-01

    A literature review of analytical techniques available for the study of compounds at low concentrations points up some of the areas where further research is needed. Compounds reviewed are sulfur dioxide, sulfuric acid, ammonium sulfate and bisulfate, metal sulfates, hydrogen sulfide, and organic sulfides. (BL)

  18. Exploring marine resources for bioactive compounds.

    PubMed

    Kiuru, Paula; DʼAuria, M Valeria; Muller, Christian D; Tammela, Päivi; Vuorela, Heikki; Yli-Kauhaluoma, Jari

    2014-09-01

    Biodiversity in the seas is only partly explored, although marine organisms are excellent sources for many industrial products. Through close co-operation between industrial and academic partners, it is possible to successfully collect, isolate and classify marine organisms, such as bacteria, fungi, micro- and macroalgae, cyanobacteria, and marine invertebrates from the oceans and seas globally. Extracts and purified compounds of these organisms can be studied for several therapeutically and industrially significant biological activities, including anticancer, anti-inflammatory, antiviral, antibacterial, and anticoagulant activities by applying a wide variety of screening tools, as well as for ion channel/receptor modulation and plant growth regulation. Chromatographic isolation of bioactive compounds will be followed by structural determination. Sustainable cultivation methods for promising organisms and biotechnological processes for selected compounds can be developed, as well as biosensors for monitoring the target compounds. The (semi)synthetic modification of marine-based bioactive compounds produces their new derivatives, structural analogs and mimetics that could serve as hit or lead compounds and be used to expand compound libraries based on marine natural products. The research innovations can be targeted for industrial product development in order to improve the growth and productivity of marine biotechnology. Marine research aims at a better understanding of environmentally conscious sourcing of marine biotechnology products and increased public awareness of marine biodiversity. Marine research is expected to offer novel marine-based lead compounds for industries and strengthen their product portfolios related to pharmaceutical, nutraceutical, cosmetic, agrochemical, food processing, material and biosensor applications.

  19. VOLATILE ORGANIC COMPOUNDS (VOCS) CHAPTER 31.

    EPA Science Inventory

    The term "volatile organic compounds' (VOCs) was originally coined to refer, as a class, to carbon-containing chemicals that participate in photochemical reactions in the ambient (outdoor) are. The regulatory definition of VOCs used by the U.S. EPA is: Any compound of carbon, ex...

  20. Three new phenolic compounds from Dalbergia odorifera.

    PubMed

    Wang, Hao; Dong, Wen-Hua; Zuo, Wen-Jian; Wang, Hui; Zhong, Hui-Min; Mei, Wen-Li; Dai, Hao-Fu

    2014-12-01

    Three new phenolic compounds (1-3) were isolated from the heartwood of Dalbergia odorifera T. Chen. (Leguminosae). Their structures were established based on spectroscopic methods including 1D and 2D NMR (HSQC, COSY, HMBC and ROESY). Compound 2 exhibited cytotoxicity against BEL-7402 tumor cell lines.

  1. Ambient Air Monitoring for Sulfur Compounds

    ERIC Educational Resources Information Center

    Forrest, Joseph; Newman, Leonard

    1973-01-01

    A literature review of analytical techniques available for the study of compounds at low concentrations points up some of the areas where further research is needed. Compounds reviewed are sulfur dioxide, sulfuric acid, ammonium sulfate and bisulfate, metal sulfates, hydrogen sulfide, and organic sulfides. (BL)

  2. A Cognitive Approach to English Nominal Compounds.

    ERIC Educational Resources Information Center

    Williams, Ray

    The ability of English as a second language (ESL) readers to comprehend different types of nominal compounds in English technical literature was investigated. College students were asked to recover the meaning of 73 nominal compounds in two technical English language articles on occupational health and safety. The intermediate and advanced ESL…

  3. PERFLUORINATED ORGANIC COMPOUND EXPOSURE ASSESSMENT RESEARCH

    EPA Science Inventory

    A wide range of perfluorinated organic compounds (PFCs) has been used in a variety of industrial processes and consumer products. The most commonly studied PFCs include perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), but there are many more compounds in this c...

  4. (CHINA) PERFLUORINATED ORGANIC COMPOUND EXPOSURE ASSESSMENT RESEARCH

    EPA Science Inventory

    A wide range of perfluorinated organic compounds (PFCs) has been used in a variety of industrial processes and consumer products. The most commonly studied PFCs include perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), but there are many more compounds in this c...

  5. Volatile organic compound emissions from silage systems

    USDA-ARS?s Scientific Manuscript database

    As a precursor to smog, emission of volatile organic compounds (VOCs) to the atmosphere is an environmental concern in some regions. The major source from farms is silage, with emissions coming from the silo face, mixing wagon, and feed bunk. The major compounds emitted are alcohols with other impor...

  6. A novel phenolic compound from Phyllanthus emblica.

    PubMed

    She, Gaimei; Cheng, Ruiyang; Sha, Lei; Xu, Yixia; Shi, Renbin; Zhang, Lanzhen; Guo, Yajian

    2013-04-01

    A new compound, mucic acid 3-O-gallate (1), was isolated from the fruit of Phyllanthus emblica L, together with 5 known compounds (2-6). Their structures were elucidated on the basis of spectroscopic analysis, including 1D and 2D NMR techniques, and by comparison with literature data.

  7. Compound estimation procedures in reliability

    NASA Technical Reports Server (NTRS)

    Barnes, Ron

    1990-01-01

    At NASA, components and subsystems of components in the Space Shuttle and Space Station generally go through a number of redesign stages. While data on failures for various design stages are sometimes available, the classical procedures for evaluating reliability only utilize the failure data on the present design stage of the component or subsystem. Often, few or no failures have been recorded on the present design stage. Previously, Bayesian estimators for the reliability of a single component, conditioned on the failure data for the present design, were developed. These new estimators permit NASA to evaluate the reliability, even when few or no failures have been recorded. Point estimates for the latter evaluation were not possible with the classical procedures. Since different design stages of a component (or subsystem) generally have a good deal in common, the development of new statistical procedures for evaluating the reliability, which consider the entire failure record for all design stages, has great intuitive appeal. A typical subsystem consists of a number of different components and each component has evolved through a number of redesign stages. The present investigations considered compound estimation procedures and related models. Such models permit the statistical consideration of all design stages of each component and thus incorporate all the available failure data to obtain estimates for the reliability of the present version of the component (or subsystem). A number of models were considered to estimate the reliability of a component conditioned on its total failure history from two design stages. It was determined that reliability estimators for the present design stage, conditioned on the complete failure history for two design stages have lower risk than the corresponding estimators conditioned only on the most recent design failure data. Several models were explored and preliminary models involving bivariate Poisson distribution and the

  8. Herbal Compounds and Toxins Modulating TRP Channels

    PubMed Central

    Vriens, Joris; Nilius, Bernd; Vennekens, Rudi

    2008-01-01

    Although the benefits are sometimes obvious, traditional or herbal medicine is regarded with skepticism, because the mechanism through which plant compounds exert their powers are largely elusive. Recent studies have shown however that many of these plant compounds interact with specific ion channels and thereby modulate the sensing mechanism of the human body. Especially members of the Transient Receptor Potential (TRP) channels have drawn large attention lately as the receptors for plant-derived compounds such as capsaicin and menthol. TRP channels constitute a large and diverse family of channel proteins that can serve as versatile sensors that allow individual cells and entire organisms to detect changes in their environment. For this family, a striking number of empirical views have turned into mechanism-based actions of natural compounds. In this review we will give an overview of herbal compounds and toxins, which modulate TRP channels. PMID:19305789

  9. Potent acetylcholinesterase inhibitory compounds from Myristica fragrans.

    PubMed

    Cuong, To Dao; Hung, Tran Manh; Han, Hyoung Yun; Roh, Hang Sik; Seok, Ji-Hyeon; Lee, Jong Kwon; Jeong, Ja Young; Choi, Jae Sue; Kim, Jeong Ah; Min, Byung Sun

    2014-04-01

    The anti-cholinesterase activity was evaluated of the ethyl acetate fraction of the methanol extract of Myristica fragrans Houtt (Myristicaceae) seeds and of compounds isolated from it by various chromatographic techniques. The chemical structures of the compounds were determined from spectroscopic analyses (NMR data). Thirteen compounds (1-13) were isolated and identified. Compound 8 { [(7S)-8'-(4'-hydroxy-3'-methoxyphenyl)-7-hydroxypropyl]benzene-2,4-diol) showed the most effective activity with an IC50 value of 35.1 microM, followed by compounds 2 [(8R,8'S)-7'-(3',4'-methylenedioxyphenyl)-8,8'-dimethyl-7-(3,4-dihydroxyphenyl)-butane] and 11 (malabaricone C) with IC50 values of 42.1 and 44.0 pM, respectively. This is the first report of significant anticholinesterase properties of M. fragrans seeds. The findings demonstrate that M. fragrans could be used beneficially in the treatment of Alzheimer's disease.

  10. Retention of Compounding Skills Among Pharmacy Students

    PubMed Central

    Eley, John G.; Birnie, Christine

    2006-01-01

    Objective To evaluate the competency of second-year pharmacy students to compound capsules from a prescription 12 months after completing a compounding course. Methods Students who completed the compounding course were given the same prescription they had been given 12 months earlier to compound metoprolol capsules. No warning of the second exercise was given and they were expected to prepare capsules and package and label the finished product. Performance was evaluated in an identical manner for both exercises based on the level of professional competency of a score of 80% or above. Results Eighty-seven percent fewer students achieved a score of 90% or more on the second exercise and 81% fewer students demonstrated the required competency. Conclusions Differences in scores on the first and second exercises indicate that pharmacy students’ level of competency and retention of knowledge with respect to compounding capsules is not adequately retained after a 12-month hiatus. PMID:17332858

  11. Odor-active compounds in cardboard.

    PubMed

    Czerny, Michael; Buettner, Andrea

    2009-11-11

    The odor-active compounds of cardboard were identified by aroma extract dilution analysis and HRGC-MS analysis. In total, 36 compounds were detected with medium to high intensities during HRGC-olfactometry. The highest odor intensities were evaluated for vanillin, (E)-non-2-enal, (R/S)-gamma-nonalactone, 2-methoxyphenol, (R/S)-delta-decalactone, p-anisaldehyde, 3-propylphenol, and a woody-smelling unknown compound. Most of the identified compounds were described as odor-active cardboard constituents for the first time. Sensory experiments demonstrated that extensive release of odor-active compounds occurred upon moistening of the cardboard. Accordingly, data indicated that the odorants are present in cardboard in relatively high amounts. In a further sensory study, a transfer of the released odor to food was demonstrated in a model experiment showing that cardboards with high odor potential can cause unwanted flavor changes in foods.

  12. Methods of making organic compounds by metathesis

    DOEpatents

    Abraham, Timothy W.; Kaido, Hiroki; Lee, Choon Woo; Pederson, Richard L.; Schrodi, Yann; Tupy, Michael John

    2015-09-01

    Described are methods of making organic compounds by metathesis chemistry. The methods of the invention are particularly useful for making industrially-important organic compounds beginning with starting compositions derived from renewable feedstocks, such as natural oils. The methods make use of a cross-metathesis step with an olefin compound to produce functionalized alkene intermediates having a pre-determined double bond position. Once isolated, the functionalized alkene intermediate can be self-metathesized or cross-metathesized (e.g., with a second functionalized alkene) to produce the desired organic compound or a precursor thereto. The method may be used to make bifunctional organic compounds, such as diacids, diesters, dicarboxylate salts, acid/esters, acid/amines, acid/alcohols, acid/aldehydes, acid/ketones, acid/halides, acid/nitriles, ester/amines, ester/alcohols, ester/aldehydes, ester/ketones, ester/halides, ester/nitriles, and the like.

  13. The natural production of organobromine compounds.

    PubMed

    Gribble, G W

    2000-03-01

    Organobromine chemicals are produced naturally by an array of biological and other chemical processes in our environment. Some of these compounds are identical to man-made organobromine compounds, such as methyl bromide, bromoform, and bromophenols, but many others are entirely new moleclar entities, often possessing extraordinary and important biological properties. Although only a few natural organobromine compounds had been discovered up to 1968, this number as of early 1999 is more than 1,600, and new examples are being discovered continually. Organobromine compounds are produced naturally by marine creatures (sponges, corals, sea slugs, tunicates, sea fans) and seaweed, plants, fungi, lichen, algae, bacteria, microbes, and some mammals. Many of these organobromine compounds are used in chemical defense, to facilitate food gathering, or as hormones.

  14. Use of model compounds in coal chemistry

    SciTech Connect

    Collins, C J

    1980-01-01

    The use of model compounds in coal chemistry has been summarized. Several examples from the literature, and also from work at Oak Ridge National Laboratory have been used to illustrate the main principles involved. The current controversy on the subject of model compounds is believed to stem from a semantic misunderstanding owing to different definitions of what a model compound is. The definition of a model compound from the organic chemist's point of view is that it is a substance which may possess at least one property or structural feature suspected of being present in the sample investigated. The sample may be coal itself, a maceral, a coal-derived material or a hydrogen-donor solvent. It is stressed that a recognition of the structure-reactivity relationship in organic compounds is necessary to avoid false conclusions.

  15. Thiophenic Sulfur Compounds Released During Coal Pyrolysis

    PubMed Central

    Xing, Mengwen; Kong, Jiao; Dong, Jie; Jiao, Haili; Li, Fan

    2013-01-01

    Abstract Thiophenic sulfur compounds are released during coal gasification, carbonization, and combustion. Previous studies indicate that thiophenic sulfur compounds degrade very slowly in the environment, and are more carcinogenic than polycyclic aromatic hydrocarbons and nitrogenous compounds. Therefore, it is very important to study the principle of thiophenic sulfur compounds during coal conversion, in order to control their emission and promote clean coal utilization. To realize this goal and understand the formation mechanism of thiophenic sulfur compounds, this study focused on the release behavior of thiophenic sulfur compounds during coal pyrolysis, which is an important phase for all coal thermal conversion processes. The pyrolyzer (CDS-5250) and gas chromatography–mass spectrometry (Focus GC-DSQII) were used to analyze thiophenic sulfur compounds in situ. Several coals with different coal ranks and sulfur contents were chosen as experimental samples, and thiophenic sulfur compounds of the gas produced during pyrolysis under different temperatures and heating rates were investigated. Levels of benzothiophene and dibenzothiophene were obtained during pyrolysis at temperatures ranging from 200°C to 1300°C, and heating rates ranging from 6°C/ms to 14°C/ms and 6°C/s to 14°C/s. Moreover, the relationship between the total amount of benzothiophene and dibenzothiophene released during coal pyrolysis and the organic sulfur content in coal was also discussed. This study is beneficial for understanding the formation and control of thiophenic sulfur compounds, since it provides a series of significant results that show the impact that operation conditions and organic sulfur content in coal have on the amount and species of thiophenic sulfur compounds produced during coal pyrolysis. PMID:23781126

  16. Thiophenic Sulfur Compounds Released During Coal Pyrolysis.

    PubMed

    Xing, Mengwen; Kong, Jiao; Dong, Jie; Jiao, Haili; Li, Fan

    2013-06-01

    Thiophenic sulfur compounds are released during coal gasification, carbonization, and combustion. Previous studies indicate that thiophenic sulfur compounds degrade very slowly in the environment, and are more carcinogenic than polycyclic aromatic hydrocarbons and nitrogenous compounds. Therefore, it is very important to study the principle of thiophenic sulfur compounds during coal conversion, in order to control their emission and promote clean coal utilization. To realize this goal and understand the formation mechanism of thiophenic sulfur compounds, this study focused on the release behavior of thiophenic sulfur compounds during coal pyrolysis, which is an important phase for all coal thermal conversion processes. The pyrolyzer (CDS-5250) and gas chromatography-mass spectrometry (Focus GC-DSQII) were used to analyze thiophenic sulfur compounds in situ. Several coals with different coal ranks and sulfur contents were chosen as experimental samples, and thiophenic sulfur compounds of the gas produced during pyrolysis under different temperatures and heating rates were investigated. Levels of benzothiophene and dibenzothiophene were obtained during pyrolysis at temperatures ranging from 200°C to 1300°C, and heating rates ranging from 6°C/ms to 14°C/ms and 6°C/s to 14°C/s. Moreover, the relationship between the total amount of benzothiophene and dibenzothiophene released during coal pyrolysis and the organic sulfur content in coal was also discussed. This study is beneficial for understanding the formation and control of thiophenic sulfur compounds, since it provides a series of significant results that show the impact that operation conditions and organic sulfur content in coal have on the amount and species of thiophenic sulfur compounds produced during coal pyrolysis.

  17. Biochemical and medical importance of vanadium compounds.

    PubMed

    Korbecki, Jan; Baranowska-Bosiacka, Irena; Gutowska, Izabela; Chlubek, Dariusz

    2012-01-01

    Vanadium belongs to the group of transition metals and is present in the air and soil contaminants in large urban agglomerations due to combustion of fossil fuels. It forms numerous inorganic compounds (vanadyl sulfate, sodium metavanadate, sodium orthovanadate, vanadium pentoxide) as well as complexes with organic compounds (BMOV, BEOV, METVAN). Depending on the research model, vanadium compounds exhibit antitumor or carcinogenic properties. Vanadium compounds generate ROS as a result of Fenton's reaction or of the reaction with atmospheric oxygen. They inactivate the Cdc25B(2) phosphatase and lead to degradation of Cdc25C, which induces G(2)/M phase arrest. In cells, vanadium compounds activate numerous signaling pathways and transcription factors, including PI3K-PKB/Akt-mTOR, NF-κB, MEK1/2-ERK, that cause cell survival or increased expression and release of VEGF. Vanadium compounds inhibit p53-dependent apoptosis and promote entry into the S phase of cells containing functional p53 protein. In addition, vanadium compounds, in particular organic derivatives, have insulin-mimetic and antidiabetic properties. Vanadium compounds lower blood glucose levels in animals and in clinical trials. They also inhibit the activity of protein tyrosine phosphatase 1B. By activating the PI3K-PKB/Akt pathway, vanadium compaunds increase the cellular uptake of glucose by the GLUT4 transporter. The PKB/Akt pathway is also used to inactivate glycogen synthase kinase-3. The impact of vanadium compounds on inflammatory reactions has not been fully studied. Vanadium pentoxide causes expression of COX-2 and the release of proinflammatory cytokines in a human lung fibroblast model. Other vanadium compounds activate NF-κB in macrophages by activating IKKβ.

  18. Water-soluble constituents of caraway: aromatic compound, aromatic compound glucoside and glucides.

    PubMed

    Matsumura, Tetsuko; Ishikawa, Toru; Kitajima, Junichi

    2002-10-01

    From the water-soluble portion of the methanolic extract of caraway (fruit of Carum carvi L.), an aromatic compound, an aromatic compound glucoside and a glucide were isolated together with 16 known compounds. Their structures were clarified as 2-methoxy-2-(4'-hydroxyphenyl)ethanol, junipediol A 2-O-beta-D-glucopyranoside and L-fucitol, respectively.

  19. IRIS Toxicological Review of Thallium and Compounds ...

    EPA Pesticide Factsheets

    Thallium compounds are used in the semiconductor industry, the manufacture of optic lenses and low-melting glass, low-temperature thermometers, alloys, electronic devices, mercury lamps, fireworks, and imitation germs, and clinically as an imaging agent in the diagnosis of certain tumors. EPA's assessment of noncancer health effects and carcinogenic potential of thallium compounds was last prepared and added to the IRIS database between 1988 and 1990. The IRIS program is preparing an assessment that will incorporate current health effects information available for thallium and compounds, and current risk assessment methods. The IRIS assessment for thallium compounds will consist of a Toxicological Review and IRIS Summary. The Toxicological Review is a critical review of the physiochemical and toxicokinetic properties of a chemical, and its toxicity in humans and experimental systems. The assessment will present reference values for the noncancer effects of thallium compounds (RfD and Rfc), and a cancer assessment. The Toxicological Review and IRIS Summary have been subject to Agency review, Interagency review, and external scientific peer review. The final product will reflect the Agency opinion on the overall toxicity of thallium and compounds. EPA is undertaking an Integrated Risk Information System (IRIS) health assessment for thallium and compounds. IRIS is an EPA database containing Agency scientific positions on potential adverse human health effec

  20. Thermodynamic properties of organic iodine compounds

    NASA Astrophysics Data System (ADS)

    Richard, Laurent; Gaona, Xavier

    2011-11-01

    A critical evaluation has been made of the thermodynamic properties reported in the literature for 43 organic iodine compounds in the solid, liquid, or ideal gas state. These compounds include aliphatic, cyclic and aromatic iodides, iodophenols, iodocarboxylic acids, and acetyl and benzoyl iodides. The evaluation has been made on the basis of carbon number systematics and group additivity relations, which also allowed to provide estimates of the thermodynamic properties of those compounds for which no experimental data were available. Standard molal thermodynamic properties at 25 °C and 1 bar and heat capacity coefficients are reported for 13 crystalline, 29 liquid, and 39 ideal gas organic iodine compounds, which can be used to calculate the corresponding properties as a function of temperature and pressure. Values derived for the standard molal Gibbs energy of formation at 25 °C and 1 bar of these crystalline, liquid, and ideal gas organic iodine compounds have subsequently been combined with either solubility measurements or gas/water partition coefficients to obtain values for the standard partial molal Gibbs energies of formation at 25 °C and 1 bar of 32 aqueous organic iodine compounds. The thermodynamic properties of organic iodine compounds calculated in the present study can be used together with those for aqueous inorganic iodine species to predict the organic/inorganic speciation of iodine in marine sediments and petroleum systems, or in the near- and far-field of nuclear waste repositories.