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Sample records for azido compounds

  1. 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.

  2. Bis(azido) compounds of Pd and Pt with bulky phosphine ligands (dppn=1,8-bis(diphenylphosphino)naphthalene, dppf=1,1‧-bis(diphenylphosphino)ferrocene, 1-dpn=1-diphenylphosphino-naphthalene): Preparation, structures, and reactivity toward isocyanides

    NASA Astrophysics Data System (ADS)

    Huh, Hyun Sue; Lee, Yeon Kyoung; Lee, Soon W.

    2006-05-01

    Pd-bis(azido) compounds [Pd(dppn)(N 3) 2] and [Pd(dppf)(N 3) 2], which contain bulky chelating bis(phosphine) ligands (dppn=1,8-bis(diphenylphosphino)naphthalene, dppf=1,1'-bis(diphenylphosphino)ferrocene), were prepared from the corresponding chlorides and NaN 3. We also prepared the Pt-bis(azido) compound [Pt(1-dpn)(SMe 2)(N 3) 2] containing a bulky monodentate phosphine (1-dpn=1-diphenylphosphino-naphthalene). All these compounds underwent [2+3] cycloaddition with isocyanides (R-NC, R=cyclohexyl, tert-butyl, 2,6-dimethylphenyl) to convert azido ligands to five-membered, C-coordinated tetrazolate rings. In addition, we observed the [Pd(dppn)Cl 2]-mediated C-C coupling of PhC tbnd6 CH to generate the η 2-PhC tbnd6 C-C tbnd6 CPh ligand. All compounds have been structurally characterized by X-ray diffraction.

  3. 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.

  4. 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

  5. Targeted Type 1 phototherapeutic agents using azido-peptide bioconjugates

    NASA Astrophysics Data System (ADS)

    Rajagopalan, Raghavan; Achilefu, Samuel I.; Jimenez, Hermo N.; Webb, Elizabeth G.; Schmidt, Michelle A.; Bugaj, Joseph E.; Dorshow, Richard B.

    2001-07-01

    Five peptides binding to somatostatin and bombesin receptors were conjugated to 4-azido-2,3,4,6-tetrafluorophenylbenzoic acid, a Type 1 photosensitizer, at the N-terminal position. The receptor affinities were determined by competition binding assay using two different pancreatic tumor cell lines, CA20948 and AR42-J, that expresses somatostatin-2 (SST-2) and bombesin receptors receptively. All compounds exhibited high receptor specificity, i.e., the IC50 values ranged between 1.0 to 64.0 nM. These conjugates may be useful for targeted Type 1 phototherapy via the generation of nitrenes at the cell surfaces expressing these receptors.

  6. Azido[1,1'-bis(diphenylphosphino)ferrocene](pentamethylcyclopentadienyl)rhodium(III) hexafluorophosphate.

    PubMed

    Han, Won Seok; Lee, Soon W

    2004-04-01

    In the title compound, azido-2kappaN-bis[micro-(1eta(5):2kappaP)-diphenylphosphinocyclopentadienyl][2(eta(5))-pentamethylcyclopentadienyl]iron(III)rhodium(III) hexafluorophosphate, [[Rh(C(10)H(15))(N(3))][Fe(micro-C(17)H(14)P)(2)

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

    DOE PAGESBeta

    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.

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

    PubMed

    Pramanik, Suman; Ghorai, Prasanta

    2013-08-01

    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. PMID:23855809

  9. Structure and magnetic behavior of a new two-dimensional antiferromagnetic manganese(II)-{mu}-1,3-azido system

    SciTech Connect

    Escuer, A.; Vicente, R.; Mautner, F.A.

    1995-11-08

    In this work we present the synthesis, X-ray crystal structure determination, and magnetic behavior of the two-dimensional compound [Mn(4acpy){sub 2}(N{sub 3}){sub 2}]{sub n}, (4acpy = 4-acetylpyridine) in which the coordination mode of the azido ligand is end-to-end. The susceptibility measurements for [Mn(4acpy){sub 2}(N{sub 3}){sub 2}]{sub n} are indicative of a moderate antiferromagnetic coupling. EPR and susceptibility data are indicative of magnetic ordering below 28 K. It is relevant to note that these magnetic measurements are the first ones for the manganese-azido(end-to-end) system. From the point of view of the design of new magnetic systems, the bridging azido ligand shows two key properties: it is a good superexchange pathway (ferromagnetic systems for the end-on coordination and antiferromagnetic for end-to-end coordination) and it frequently leads to nontrivial systems with nuclearity greater than 2. At the present, magnetic studies on the manganese-azido-bridged systems have been performed only for the dinuclear compound ({mu}-1,1-N{sub 3})[Mn(terpy)]{sub 2}{center_dot}H{sub 2}O, which shows ferromagnetic coupling (J/k = + 3.5 K), following the general trends found for analogous Cu(II) and Ni(II) 1,1-azido systems. The structure of the title compound shows that each manganese atom is octahedrally coordinated to four azido ligands and two molecules of 4-acetylpyridine in trans arrangement. Antiferromagnetic interactions were evident from susceptibility data.

  10. 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.

  11. 5-Bromo (or chloro)-6-azido-5,6-dihydro-2' -deoxyuridine and -thymidine derivatives with potent antiviral activity.

    PubMed

    Kumar, Rakesh

    2002-02-11

    Synthesis, antiviral, and cytotoxic activities of 5-bromo (or chloro)-6-azido-5,6-dihydro-2' -deoxyuridine (4,5) and -thymidine (6,7) are reported. Compounds 4 and 5 exhibited a broad spectrum of antiherpes activity against (HSV-1, HSV-2, HCMV, and VZV). PMID:11814776

  12. 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

  13. Solid-state hierarchical cyclodextrin-based supramolecular polymer constructed by primary, secondary, and tertiary azido interactions.

    PubMed

    Ménand, Mickaël; Adam de Beaumais, Ségolène; Chamoreau, Lise-Marie; Derat, Etienne; Blanchard, Sébastien; Zhang, Yongmin; Bouteiller, Laurent; Sollogoub, Matthieu

    2014-07-01

    The crystallization of a di-azido-α-cyclodextrin revealed a polymeric self-assembly involving a variety of azido-type interactions. The crystal arrangement relies on the cooperativity of a primary azido inclusion, a secondary azido-azido interaction involving an unprecedented distribution of canonical forms, and a tertiary azido-groove interaction. The second azido group brings in a major contribution to the supramolecular structure illustrating the benefit of a difunctionalization for the generation of hierarchy. PMID:24866704

  14. Radioiodinated O6-Benzylguanine Derivatives Containing an Azido Function

    PubMed Central

    Vaidyanathan, Ganesan; White, Benjamin; Affleck, Donna J.; McDougald, Darryl; Zalutsky, Michael R.

    2010-01-01

    Introduction Drug resistance to alkylator chemotherapy has been primarily attributed to the DNA repair protein alkylguanine-DNA alkyltransferase (AGT); thus, personalizing chemotherapy could be facilitated if tumor AGT content could be quantified prior to administering chemotherapy. We have been investigating the use of radiolabeled O6-benzylguanine (BG) analogues to label and quantify AGT in vivo. BG derivatives containing an azido function were sought to potentially enhance the targeting of these analogues to AGT, which is primarily present in the cell nucleus, either by conjugating them to nuclear localization sequence (NLS) peptides or by pretargeting via bioorthogonal approaches. Methods Two O6-(3-iodobenzyl)guanine (IBG) derivatives containing an azido moiety—O6-(4-azidohexyloxymethyl-3-iodobenzyl)guanine (AHOMIBG) and O6-(4-azido-3-iodobenzyl)guanine (AIBG)—and their tin precursors were synthesized in multiple steps and the tin precursors were converted to radioiodinated AHOMIBG and AIBG, respectively. Both unlabeled and radioiodinated AHOMIBG analogues were conjugated to alkyne-derivatized NLS peptide heptynoyl-PK3RKV. The ability of these radioiodinated compounds to bind to AGT was determined by a trichloroacetic acid precipitation assays and gel electrophoresis/phosphor imaging. Labeling of an AGT-AIBG conjugate via Staudinger ligation using the 131I-labeled phosphine ligand, 2-(diphenylphosphino)phenyl 4-[131I]iodobenzoate, also was investigated. Results [131I]AHOMIBG was synthesized in two steps from its tin precursor in 52.2 ± 7.5% (n = 5) radiochemical yield and conjugated to the NLS peptide via click reaction in 50.7 ± 4.9% (n = 6) yield. The protected tin precursor of AIBG was radioiodinated in an average radiochemical yield of 69.6 ± 4.5% (n = 7); deprotection of the intermediate gave [131I]AIBG in 17.8 ± 4.2% (n = 9) yield. While both [131I]AHOMIBG and its NLS conjugate bound to AGT pure protein, their potency as a substrate for AGT was

  15. Synthesis and antiviral activity of novel acyclic nucleoside analogues of 5-(1-azido-2-haloethyl)uracils.

    PubMed

    Kumar, R; Sharma, N; Nath, M; Saffran, H A; Tyrrell, D L

    2001-11-22

    We present the discovery of a novel category of 5-substituted acyclic pyrimidine nucleosides as potent antiviral agents. A series of 1-[(2-hydroxyethoxy)methyl] (5-7), 1-[(2-hydroxy-1-(hydroxymethyl)ethoxy)methyl] (8-10), and 1-[4-hydroxy-3-(hydroxymethyl)-1-butyl] (11-13) derivatives of 5-(1-azido-2-haloethyl)uracil were synthesized and evaluated for their biological activity in cell culture. 1-[4-Hydroxy-3-(hydroxymethyl)-1-butyl]-5-(1-azido-2-chloroethyl)uracil (12) was the most effective antiviral agent in the in vitro assays against DHBV (EC(50) = 0.31-1.55 microM) and HCMV (EC(50) = 3.1 microM). None of the compounds investigated showed any detectable toxicity to several stationary and proliferating host cells. PMID:11708924

  16. Novel heterometallic metal–azido complex synthesized by “one-step” reaction: synthetic strategy and magnetic properties

    SciTech Connect

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

    2013-06-15

    A novel heterometallic complex, [Ni{sub 2}Mn(N{sub 3}){sub 2}(nic){sub 4}·(H{sub 2}O){sub 2}]{sub n} (1) (nic=nicotinate), was obtained by assembling MnCl{sub 2}·4H{sub 2}O, Ni(NO{sub 3}){sub 2}·6H{sub 2}O, NaN{sub 3} 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 Ni{sup II} and Mn{sup II} ions in the trimer. - Graphical abstract: A novel heterometallic 3D complex [Ni{sub 2}Mn(N{sub 3}){sub 2}(nic){sub 4}·(H{sub 2}O){sub 2}]{sub n} (1) (nic=nicotinate) was synthesized by hydrothermal reaction. This complex exhibits interesting structural and magnetic properties. - Highlights: • It is difficult to construct simple coordination complexes with azide as “ligands” to obtain heterometallic metal–azido compounds. • A “one-step” method—hydrothermal reaction— was introduced to avoid the disadvantages of azide mentioned above. • The magnetic property is different with the isostructural homometal–azido complex due to the changed metal center.

  17. Combinations of 3'-azido-3'-deoxythymidine (zidovudine) and phosphonoformate (foscarnet) against human immunodeficiency virus type 1 and cytomegalovirus replication in vitro.

    PubMed Central

    Eriksson, B F; Schinazi, R F

    1989-01-01

    Combinations of 3'-azido-3'-deoxythymidine and phosphonoformate produced a moderate synergistic inhibitory effect against human immunodeficiency virus type 1 in vitro at concentrations that are easily achieved in humans. The synergistic effect was more pronounced with increasing concentrations and was not secondary to toxic effects of the drugs. 3'-Azido-3'-deoxythymidine neither inhibited the replication of human cytomegalovirus in human embryonic lung fibroblasts nor interfered with the anticytomegalovirus effect of phosphonoformate. By using partially purified reverse transcriptase of human immunodeficiency virus type 1 and human cytomegalovirus DNA polymerase, various combinations of 3'-azido-3'-deoxythymidine-5'-triphosphate and phosphonoformate produced strong indications of additive interactions. The synergistic interactions in infected cells and the additive effects observed at the reverse transcriptase level indicate that mechanisms other than the reverse transcriptase may be of importance for the inhibition of human immunodeficiency virus replication by these two compounds. A concomitant treatment of cytomegalovirus infections, such as cytomegalovirus retinitis, with phosphonoformate in patients with acquired immunodeficiency syndrome receiving 3'-azido-3'-deoxythymidine may be appropriate, and this combination may also be useful in controlling human immunodeficiency virus infection. PMID:2546487

  18. Two novel azido-copper(II) complexes with 4-(1H-tetrazol-1-yl) carboxylate: Synthesis, crystal structure, and magnetism

    NASA Astrophysics Data System (ADS)

    Zhang, Shu-Ming; Chen, Yu-Huan; Wang, Li-Hua; Wang, Gui-Xiang

    2015-03-01

    Using same reactants with different mol ratio, two novel azido-copper(II) compounds [Cu(L)(N3)]n (1) and {[Cu3(L)2(N3)4](CH3OH)3}n (2) {HL=4-(1H-tetrazol-1-yl) benzoic acid} have been synthesized by the method of liquid diffusion at room temperature and structurally characterized. Single crystal X-ray diffraction analyses show that complex 1 has a two dimensional (2D) coordination structure with carboxylate/EO (end on)-azido mixed-bridged copper(II) chains, while 2 possesses different Cu -N3 - /COO- one dimensional (1D) chains from that of 1, with double EE (end to end) azido bridge and carboxylate/EO-azido mixed-bridge coexisting, forming a 2D supramolecular framework by interchain H-bonds. The structural difference between 1 and 2 suggests that the tetrazolyl motif also has important influence on the construction of these complexes. Magnetic study indicates that domain ferromagnetic coupling interactions exist in both 1 and 2.

  19. 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.

  20. 3α-Azido-5-cholestene

    PubMed Central

    Houston, Todd A.; Quader, Sabina; Boyd, Sue E.; Jenkins, Ian D.; Healy, Peter C.

    2008-01-01

    The crystal structure of the title compound, C27H45N3, has been determined as part of our investigation into the hydro­phobic modification of amino­glycoside anti­biotics. The isopropyl group showed disorder for the tertiary carbon (equal occupancies), with high thermal motion for the peripheral atoms of the isopropyl and azide groups also apparent in the structure. The axial disposition of the azide group is consistent with the clean inversion of stereochemistry at C-3 under Mitsunobu conditions. PMID:21201721

  1. Synthesis of photoactivatable azido-acyl caged oxazine fluorophores for live-cell imaging.

    PubMed

    Anzalone, Andrew V; Chen, Zhixing; Cornish, Virginia W

    2016-07-19

    We report the design and synthesis of a photoactivatable azido-acyl oxazine fluorophore. Photoactivation is achieved cleanly and rapidly with UV light, producing a single fluorescent oxazine photoproduct. We demonstrate the utility of azido-acyl caged oxazines for protein specific labeling in living mammalian cells using the TMP-tag technology. PMID:27377037

  2. Relaxation of isolated taenia coli of guinea-pig by enantiomers of 2-azido analogues of adenosine and adenine nucleotides.

    PubMed Central

    Cusack, N. J.; Planker, M.

    1979-01-01

    1 2-Azido photoaffinity analogues of adenosine 5'triphosphate (ATP), adenosine 5'-diphosphate (ADP), adenosine 5'-monophosphate (AMP), and adenosine have been synthesized and tested on guinea-pig taenia coli. 2 2-Azido-ATP and 2-azido-ADP were approximately 20 times more potent than ATP as relaxants of taenia coli, and required prolonged washout times before recovery of the muscle. 3 2-Azido-AMP and 2-azidoadenosine were 2 to 12 times more potent than ATP, but took much longer (up to 100 s) to reach maximal relaxation. This behaviour is different from that of AMP and adenosine which were much less potent than ATP. 4 L-Enantiomers of adenosine and adenine nucleotides were also tested. L-ATP and L-ADP were 3 to 6 times less potent than ATP and ADP, and L-AMP and L-adenosine were inactive. 2-Azido-L-ATP and 2-azido-L-ADP were approximately 120 times less potent than 2-Azido-ATP and 6 times less potent than ATP as relaxants of taenia coli. 2-Azido-L-AMP and 2-azidio-L-adenosine were almost inactive. 5 2-Azido derivatives are photolysed by u.v. irradiation to reactive intermediates. 2-Azido-ATP and 2-azidoadenosine might be suitable photoaffinity ligands for labelling putative P2 and P1 purine receptors respectively. 2-Azido-L-ATP and 2-azido-L-adenosine could be useful controls for nonspecific labelling. PMID:497519

  3. Azido derivatives of cellobiose: oxidation at C1 with cellobiose dehydrogenase from Sclerotium rolfsii.

    PubMed

    Mulla, Dafina; Kracher, Daniel; Ludwig, Roland; Nagy, Gabor; Grandits, Melanie; Holzer, Wolfgang; Saber, Yasser; Gabra, Nermeen; Viernstein, Helmut; Unger, Frank M

    2013-12-15

    We report the chemo-enzymatic synthesis of three cellobiono-1,5-lactone azido derivatives, designed as building blocks for biomedical polymer scaffolds. The synthesis is based on regioselective protection of cellobiose or 1,6-O-anhydro-β-d-cellobiose before azidation and subsequent deprotection. The oxidation to the corresponding cellobiono-1,5-lactones was investigated with 6'-azido-6'-deoxycellobiose (6'N3Clb, 5), 6-azido-6-deoxycellobiose (6N3Clb, 11) and 2-azido-2-deoxycellobiose (2N3Clb, 15) under the catalysis of cellobiose dehydrogenase (CDH) from the plant-pathogenic fungus Sclerotium rolfsii. Substrate binding characteristics and kinetics of CDH for the three cellobiose azido derivatives were studied employing computational docking, steady-state and presteady-state techniques. The process of enzymatic oxidation of the cellobiose azido intermediates was optimized by using the available kinetic information. Whereas the conversion of 15 by CDH is very slow, the conversion of 5 and 11 by a regenerated, bi-enzymatic process (CDH/redox mediator/laccase/O2) is fast, quantitative and produces azido derivatives of cellobiono-1,5-lactone in an environmentally friendly, oxygen-driven process. PMID:24211370

  4. Inhibition of nucleoside diphosphate kinase in rat liver mitochondria by added 3'-azido-3'-deoxythymidine.

    PubMed

    Valenti, D; Barile, M; Quagliariello, E; Passarella, S

    1999-02-12

    The effect of 3'-azido-3'-deoxythymidine on nucleoside diphosphate kinase of isolated rat liver mitochondria has been studied. This is done by monitoring the increase in the rate of oxygen uptake by nucleoside diphosphate (TDP, UDP, CDP or GDP) addition to mitochondria in state 4. It is shown that 3'-azido-3'-deoxythymidine inhibits the mitochondrial nucleoside diphosphate kinase in a competitive manner, with a Ki value of about 10 microM as measured for each tested nucleoside diphosphate. It is also shown that high concentrations of GDP prevent 3'-azido-3'-deoxythymidine inhibition of the nucleoside diphosphate kinase. PMID:10050777

  5. 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. PMID:26340222

  6. 6-Azido-6-deoxy-l-idose as a Hetero-Bifunctional Spacer for the Synthesis of Azido-Containing Chemical Probes.

    PubMed

    Hamagami, Hiroki; Kumazoe, Motofumi; Yamaguchi, Yoshiki; Fuse, Shinichiro; Tachibana, Hirofumi; Tanaka, Hiroshi

    2016-08-26

    The design of 6-azido-6-deoxy-l-idose for use as a hetero-bifunctional spacer is reported. The hemiacetal at one terminus is an equivalent of an aldehyde and can react with nucleophiles, such as amino groups and electron-rich aromatics. The azido group at the other terminus bio-orthogonally undergoes a Hüisgen [3+2] cycloaddition with an acetylene. The idose derivative exhibited a higher level of reactivity towards oxime formation than a corresponding glucose derivative. The (13) C NMR spectrum of the uniformly (13) C-labeled 6-azido-idose indicated that the acyclic forms of the sugar totaled 0.3 % of all the isomers, whereas those of glucose totaled 0.01 %. The larger population of the acyclic forms of the idose derivative would result in higher reactivity towards electrophilic addition in comparison with glucose derivatives. Finally, we prepared a C-idosyl epigallocatechin gallate (EGCG) that bears an azido group through C-glycosylation of EGCG with 6-azido-idose. This glycosyl form of the C-idosyl EGCG exhibited a cytotoxicity against U266 cells that was comparable to that of EGCG. These results suggested that the EGCG derivative could be used as an effective chemical probe for the elucidation of EGCG biological functions. PMID:27482948

  7. Fourier transform infrared characterization of the azido complex of methane monooxygenase hydroxylase from Methylococcus capsulatus (Bath).

    PubMed

    Lu, Shen; Sazinsky, Matthew H; Whittaker, James W; Lippard, Stephen J; Moënne-Loccoz, Pierre

    2005-03-30

    The azido complex formed in oxidized methane monooxygenase from Methylococcus capsulatus (Bath) was investigated with resonance Raman and FTIR techniques. These experiments show the presence of a nuas(NNN) at approximately 2077 cm-1 which splits to two components at 2059 and 2073 cm-1 with 15N14N2. The vibrational data are assigned to an azido complex bound terminally to one iron(III) at the diiron center. When the azido complex is illuminated at 15 K, a new nuas(NNN) is observed at 2136 cm-1 which is assigned to a photodissociated HN3 within the substrate pocket. We propose a model where an aqua ligand engages a hydrogen bond interaction with the 1N atom of the azido group and acts as at a proton donor during the photolysis process. PMID:15783178

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

    PubMed

    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

    2011-09-01

    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 (k(pol)/K(d)) 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

  9. Solvent-induced syntheses, crystal structures, magnetic properties, and single-crystal-to-single-crystal transformation of azido-Cu(II) coordination polymers with 2-naphthoic acid as co-ligand.

    PubMed

    Liu, Xiangyu; Cen, Peipei; Li, Hui; Ke, Hongshan; Zhang, Sheng; Wei, Qing; Xie, Gang; Chen, Sanping; Gao, Shengli

    2014-08-01

    Based on the solvent-induced effect, three new azido-copper coordination polymers--[Cu(2-na)(N3)] (1), [Cu(2-na)(N3)] (2), and [Cu(2-na)(N3)(C2H5OH)] (3) (where 2-na = 2-naphthoic acid)--have been successfully prepared. Structure analysis shows that the Cu(II) cations in compounds 1-3 present tetra-, penta-, and hexa-coordination geometries, respectively. Compound 1 is a well-isolated one-dimensional (1D) chain with the EO-azido group, while 2 is an isomer of 1 and exhibits a two-dimensional (2D) layer involving the EE-azido group. Thermodynamically, density functional theory (DFT) calculation reveals that 2 occupies the stable state and 1 locates in the metastable state. Compound 3 consists of a 1D chain with triple bridging mode, which is derived from 1, and undergoes a single-crystal-to-single-crystal transformation by soaking in ethanol solvent; the powdery product of 1, namely 1b, could be yielded after the dealcoholization of compound 3. Magnetic measurements indicate that compounds 1-3 perform strong intrachain ferromagnetic interactions, experiencing long-range magnetic ordering and slow magnetic relaxation. Compound 1 features the metamagnetic behavior with a transition temperature of 15 K, while 2 and 3 display spin glass behavior with the phase transition temperatures of 15 and 12 K, respectively. Magneto-structure relationships are investigated as well. PMID:25014208

  10. Synthesis of quinoxaline azido and amino reverse ribofuranoside and their O-regioisomers.

    PubMed

    Ali, Ibrahim A I

    2014-01-01

    A series of quinoxaline azido reverse nucleosides 3a-c and their O-regioisomers 4a-c was prepared by reaction of quinoxaline 1a-c with 3-azido-3-deoxy-1,2-O-isopropylidene-5-p-toluenesulfonyl-D-ribofuranose (2) in the presence of sodium hydride. Structure modification of these interesting structures includes reduction and the subsequent acetylation reactions to give quinoxaline amino and acetyl amino reverse nucleosides and their O-regioisomers. PMID:24689845

  11. Azido Auxins: Synthesis and Biological Activity of Fluorescent Photoaffinity Labeling Agents 12

    PubMed Central

    Melhado, L. Lee; Jones, Alan M.; Leonard, Nelson J.; Vanderhoef, Larry N.

    1981-01-01

    Three auxin analogs, 4−, 5−, and 6-azido-3-indoleacetic acid (4-N3-IAA, 5-N3-IAA, and 6-N3-IAA) have been synthesized for use as fluorescent photoaffinity labeling agents. The pKa values of these compounds (4-N3-IAA, 4.67; 5-N3-IAA, 4.65; 6-N3-IAA, 4.66; all ± 0.04) are experimentally indistinguishable from the pKa of 3-indoleacetic acid (IAA, 4.69 ± 0.04). The auxin activity of these IAA derivatives has been determined in several systems. In soybean, pea, and corn straight growth assays, all three analogs induce growth comparable to that caused by IAA. In the tobacco pith assay, all three analogs elicit a maximum increase in fresh weight at least 40 to 50% of that caused by IAA. Optimal growth is attained in the tobacco pith assay at slightly higher concentrations of 4-N3-IAA and 6-N3-IAA (30 micromolar) than required for IAA (10 micromolar); however, maximal growth is achieved at a slightly lower concentration of 5-N3-IAA (3 micromolar). The N3-IAAs, like IAA, are transported basipetally through tobacco pith tissue. PMID:16661939

  12. 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. PMID:22462539

  13. 8-Azido double-stranded RNA photoaffinity probes. Enzymatic synthesis, characterization, and biological properties of poly(I,8-azidoI).poly(C) and poly(I,8-azidoI).poly(C12U) with 2',5'-oligoadenylate synthetase and protein kinase.

    PubMed

    Li, S W; Moskow, J J; Suhadolnik, R J

    1990-04-01

    The technique of photoaffinity labeling has been applied to the double-stranded RNA (dsRNA)-dependent enzyme 2',5'-oligoadenylate (2-5A) synthetase to provide a means for the examination of RNA-protein interaction(s) in the dsRNA allosteric binding domain of this enzyme. The synthesis, characterization, and biological properties of the photoaffinity probe poly[( 32P]I,8-azidoI).poly(C) and its mismatched analog poly[( 32P]I,8-azidoI).poly(C12U), which mimic the parent molecules poly(I).poly(C) and poly(I).poly(C12U), are described. The efficacy of poly[( 32P]I,8-azidoI).poly(C) and poly[( 32P]I,8-azidoI).poly(C12U) as allosteric site-directed activators is demonstrated using highly purified 2-5A synthetase from rabbit reticulocyte lysates and from extracts of interferon-treated HeLa cells. The dsRNA photoprobes activate these two 2-5A synthetases. Saturation of 2-5A synthetase is observed at 6 x 10(-4) g/ml poly[( 32P]I,8-azidoI).poly(C) following photolysis for 20 s at 0 degrees C. The photoincorporation of poly[( 32P]I,8-azidoI).poly(C) is specific, as demonstrated by the prevention of photoincorporation by native poly(I).poly(C). DNA, poly(I), and poly(C) are not competitors of poly[( 32P]I,8-azidoI).poly(C). Following UV irradiation of 2-5A synthetase with poly[( 32P]I,8-azidoI).poly(C), the reaction mixture is treated with micrococcal nuclease to hydrolyze azido dsRNA that is not cross-linked to the enzyme. A radioactive band of 110 kDa (the same as that reported for native rabbit reticulocyte lysate 2-5A synthetase) is observed following sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography. The specific photolabeling of the 2-5A synthetase suggests that the azido dsRNA is intrinsic to the allosteric binding domain. The utility of poly[( 32P]I,8-azidoI).poly(C) for the detection of dsRNA-dependent binding proteins and the isolation of peptides at or near the allosteric binding site is discussed. PMID:2318823

  14. 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

  15. 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. PMID:26272428

  16. 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.

  17. 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.

  18. 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.

  19. Synthesis and Protein Incorporation of Azido-Modified Unnatural Amino Acids

    PubMed Central

    Tookmanian, Elise M.; Fenlon, Edward E.; Brewer, Scott H.

    2015-01-01

    Two new azidophenylalanine residues (3 and 4) have been synthesized and, in combination with 4-azido-L-phenylalanine (1) and 4-azidomethyl-L-phenylalanine (2), form a series of unnatural amino acids (UAAs) containing the azide vibrational reporter at varying distances from the aromatic ring of phenylalanine. These UAAs were designed to probe protein hydration with high spatial resolution by utilizing the large extinction coefficient and environmental sensitivity of the azide asymmetric stretch vibration. The sensitivity of the azide reporters was investigated in solvents that mimic distinct local protein environments. Three of the four azido-modified phenylalanine residues were successfully genetically incorporated into a surface site in superfolder green fluorescent protein (sfGFP) utilizing an engineered, orthogonal aminoacyl-tRNA synthetase in response to an amber codon with high efficiency and fidelity. SDS-PAGE and ESI-Q-TOF mass analysis verified the site-specific incorporation of these UAAs. The observed azide asymmetric stretch in the linear IR spectra of these UAAs incorporated into sfGFP indicated that the azide groups were hydrated in the protein. PMID:26478813

  20. Bisheteroarylpiperazine reverse transcriptase inhibitor in combination with 3'-azido-3'-deoxythymidine or 2',3'-dideoxycytidine synergistically inhibits human immunodeficiency virus type 1 replication in vitro.

    PubMed Central

    Chong, K T; Pagano, P J; Hinshaw, R R

    1994-01-01

    Bisheteroarylpiperazine compounds are nonnucleoside reverse transcriptase inhibitors of human immunodeficiency virus type 1 (HIV-1). To provide a rationale for combination therapy with a second-generation bisheteroarylpiperazine, we investigated the effect of U-90152 in combination with 3'-azido-3'-deoxythymidine (AZT) or 2',3'-dideoxycytidine (ddC). HIV-1-infected cells were cultured in the presence of test compounds, and drug effects on p24 core antigen production were measured by an enzyme-linked immunosorbent assay. In a CD4+ T-cell line (H9) infected with HIV-1IIIB, the 50% effective concentrations for U-90152, AZT, and ddC were 6.0, 80.4, and 31.8 nM, respectively. In human peripheral blood mononuclear cells infected with the molecularly cloned clinical isolate HIV-1JRCSF, the 50% effective concentrations for U-90152, AZT, and ddC were 5.3, 5.9, and 25.0 nM, respectively. Over a range of drug concentrations (U-90152 and AZT at 0.3, 1, 3, 10, and 30 nM; ddC at 3, 10, 30, and 100 nM), U-90152 in combination with AZT or ddC synergistically inhibited the replication of a laboratory-adapted strain and a clinical isolate of HIV-1. PMID:7514857

  1. 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.

  2. 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.

  3. 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.

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

    DOEpatents

    Huynh, My Hang V.; Hiskey, Michael A.

    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.

  5. 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.

  6. ω-Azido fatty acids as probes to detect fatty acid biosynthesis, degradation, and modification[S

    PubMed Central

    Pérez, Alexander J.; Bode, Helge B.

    2014-01-01

    FAs play a central role in the metabolism of almost all known cellular life forms. Although GC-MS is regarded as a standard method for FA analysis, other methods, such as HPLC/MS, are nowadays widespread but are rarely applied to FA analysis. Here we present azido-FAs as probes that can be used to study FA biosynthesis (elongation, desaturation) or degradation (β-oxidation) upon their uptake, activation, and metabolic conversion. These azido-FAs are readily accessible by chemical synthesis and their metabolic products can be easily detected after click-chemistry based derivatization with high sensitivity by HPLC/MS, contributing a powerful tool to FA analysis, and hence, lipid analysis in general. PMID:25013232

  7. 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.

  8. In vivo efficacy of zidovudine (3'-azido-3'-deoxythymidine) in experimental gram-negative-bacterial infections.

    PubMed Central

    Keith, B R; White, G; Wilson, H R

    1989-01-01

    The therapeutic efficacy of orally administered zidovuldine (3'-azido-3'-deoxythymidine) was determined in animals infected with Escherichia coli and Salmonella dublin. The 50% effective dose (ED50) of zidovudine (9.6 to 11.8 mg/kg of body weight) compared favorably with that of trimethoprim (19.4 to 22.2 mg/kg) in mice with systemic E. coli infection. At 50 mg/kg, both zidovudine and ampicillin reduced the number of bacteria in the kidneys of mice and prevented lethal infection in mice with ascending pyelonephritis caused by E. coli. Zidovudine prevented a lethal S. dublin infection in calves over a wide dose range (8.0 to 31.0 mg/kg per day). Zidovudine levels in plasma of uninfected mice were 28.2 +/- 4.5 and 7.9 +/- 2.2 micrograms/ml at 30 and 60 min, respectively, exceeding the MICs for the bacteria used in the infections. Few zidovudine-resistant strains were observed. The in vivo data raise the possibility that zidovudine may have an antibacterial effect in patients receiving this therapy. PMID:2658792

  9. 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.

  10. α-Azido Acids in Solid-Phase Peptide Synthesis: Compatibility with Fmoc Chemistry and an Alternative Approach to the Solid Phase Synthesis of Daptomycin Analogs.

    PubMed

    Lohani, Chuda Raj; Rasera, Benjamin; Scott, Bradley; Palmer, Michael; Taylor, Scott D

    2016-03-18

    α-Azido acids have been used in solid phase peptide synthesis (SPPS) for almost 20 years. Here we report that peptides bearing an N-terminal α-azidoaspartate residue undergo elimination of an azide ion when treated with reagents that are commonly used for removing the Fmoc group during SPPS. We also report an alternative solid-phase route to the synthesis of an analog of daptomycin that uses a reduced number of α-azido amino acids and without elimination of an azide ion. PMID:26938305

  11. Synthesis, characterisation and photochemistry of Pt(IV) pyridyl azido acetato complexes.

    PubMed

    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

    2009-04-01

    Pt(II) azido complexes [Pt(bpy)(N(3))(2)] (1), [Pt(phen)(N(3))(2)] (2) and trans-[Pt(N(3))(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 (N(3)-Pt-N(3) angle 146.7 degrees ) as a result of steric congestion at the Pt centre. The novel Pt(IV) complexes trans, cis-[Pt(bpy)(OAc)(2)(N(3))(2)] (), trans, cis-[Pt(phen)(OAc)(2)(N(3))(2)] (), trans, trans, trans-[Pt(OAc)(2)(N(3))(2)(py)(2)] (), were obtained from via oxidation with H(2)O(2) 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 TD-DFT (time-dependent density functional theory). These Pt(IV) complexes exhibit greater absorption at longer wavelengths (epsilon = 9756 M(-1) cm(-1) at 315 nm for 4 ; epsilon = 796 M(-1) cm(-1) at 352 nm for 5 ; epsilon = 16900 M(-1) cm(-1) at 307 nm for 6 , in aqueous solution) than previously reported Pt(IV) 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 Pt(II) and Pt(IV) electronic and structural properties allowed further elucidation of the photochemistry of 4-6. PMID:19290364

  12. Structural and magnetic modulations of copper(II) azido complexes: unexpected in situ reactions of mono-N-donor pyridine-based co-ligands.

    PubMed

    Zhao, Jiong-Peng; Xie, Yabo; Li, Jian-Rong; Bu, Xian-He

    2016-01-28

    Low-temperature hydrothermal reactions of copper salts with NaN3 and structurally related pyridine-based ligands, 1-(4-pyridyl)pyridinium, 3-chloromethylpyridine, 4-benzylpyridine, and quinoline (L(4)), respectively, led to the formation of four new magnetic complexes, [Cu3(L(1))2(N3)6]n (), [Cu3(L(2))2(N3)6]n (), [Cu(L(3))2(N3)2] (), and [Cu(L(4))(N3)2]n (). In these complexes, L(1), L(2), and L(3) are pyridine, 3-azidomethylpyridine, and 4-benzoylpyridine, being generated in situ by the decomposition, azido substitution, and oxidation reaction of the 1-(4-pyridyl)pyridinium, 3-chloromethylpyridine, and 4-benzylpyridine, respectively. and have similar structures being composed of double end-on azido-bridging planar [Cu3(L)2(N3)6] trinuclear units, which are further linked into a two-dimensional layer by the end-to-end azido bridges of themselves, along with their weak end-on coordination. It is interesting that the only slight differences of geometrical parameters in and have led to distinct magnetic interactions between the trinuclear units, where the former is antiferromagnetic but the latter is ferromagnetic, whereas has a mono-nuclear core structure, which is further extended to a one-dimensional (1D) chain by weakly coordinated end-on azido bridges. consists of unique 1D chains with double end-on azido bridge bonding distorted five-coordinated Cu(ii) centers, and exhibits ferromagnetic intrachain interactions. In the structures of these complexes there also exist weak inter-layer or inter-chain hydrogen bonds, which should also be responsible for some magnetic behavior at low temperature. In addition, primary structural and magnetic comparisons and discussions have also been performed by combining other reported azido-Cu(ii) systems with related pyridyl-based co-ligands. These results show that the selection of synthesis conditions and slight decoration of co-ligands (or geometric differences of them) have important influences on the structures and magnetic

  13. Spectroscopic, viscositic and molecular modeling studies on the interaction of 3'-azido-daunorubicin thiosemicarbazone with DNA.

    PubMed

    Cui, Fengling; Liu, Qingfeng; Luo, Hongxia; Zhang, Guisheng

    2014-01-01

    A new daunorubicin has been synthesized and structurally characterized. The interaction of native calf thymus DNA (ctDNA) with 3'-azido-daunorubicin thiosemicarbazone (ADNRT) was investigated under simulated physiological conditions by multi-spectroscopic techniques, viscometric measurements and molecular modeling study. It concluded that ADNRT could intercalate into the base pairs of ctDNA, and the fluorescence quenching by ctDNA was static quenching type. Thermodynamic parameters calculated suggested that the binding of ADNRT to ctDNA was mainly driven by hydrophobic interactions. The relative viscosity of ctDNA increased with the addition of ADNRT, which confirmed the intercalation mode. Furthermore, molecular modeling studies corroborate the above experimental results. PMID:23974700

  14. Metabolic Labeling of Caenorhabditis elegans Primary Embryonic Cells with Azido-Sugars as a Tool for Glycoprotein Discovery

    PubMed Central

    Burnham-Marusich, Amanda R.; Snodgrass, Casey J.; Johnson, Anna M.; Kiyoshi, Conrad M.; Buzby, Sarah E.; Gruner, Matt R.; Berninsone, Patricia M.

    2012-01-01

    Glycobiology research with Caenorhabditis elegans (C. elegans) has benefitted from the numerous genetic and cell biology tools available in this system. However, the lack of a cell line and the relative inaccessibility of C. elegans somatic cells in vivo have limited the biochemical approaches available in this model. Here we report that C. elegans primary embryonic cells in culture incorporate azido-sugar analogs of N-acetylgalactosamine (GalNAc) and N-acetylglucosamine (GlcNAc), and that the labeled glycoproteins can be analyzed by mass spectrometry. By using this metabolic labeling approach, we have identified a set of novel C. elegans glycoprotein candidates, which include several mitochondrially-annotated proteins. This observation was unexpected given that mitochondrial glycoproteins have only rarely been reported, and it suggests that glycosylation of mitochondrially-annotated proteins might occur more frequently than previously thought. Using independent experimental strategies, we validated a subset of our glycoprotein candidates. These include a mitochondrial, atypical glycoprotein (ATP synthase α-subunit), a predicted glycoprotein (aspartyl protease, ASP-4), and a protein family with established glycosylation in other species (actin). Additionally, we observed a glycosylated isoform of ATP synthase α-subunit in bovine heart tissue and a primate cell line (COS-7). Overall, our finding that C. elegans primary embryonic cells are amenable to metabolic labeling demonstrates that biochemical studies in C. elegans are feasible, which opens the door to labeling C. elegans cells with other radioactive or azido-substrates and should enable the identification of additional post-translationally modified targets and analysis of the genes required for their modification using C. elegans mutant libraries. PMID:23152843

  15. Synthesis and characterization of two 1D polymeric zinc(II) azido complexes derived from pyridine-N-oxide co-ligands

    NASA Astrophysics Data System (ADS)

    Mautner, Franz A.; Berger, Christian; Massoud, Salah S.

    2016-04-01

    The synthesis and structural characterization of two new polymeric zinc(II) azido complexes with pyridine-N-oxide derivative co-ligands, namely catena-[Zn(4-methylpyridine-N-oxide)(μ1,1-N3)2] (1) and catena-{[Zn2(μ2-isonicotinato-N-oxide)2(μ1,1-N3)2(H2O)3](H2O)} (2) are reported. Single crystal structure determination revealed the penta-coordinated geometry of the Zn(II) centers in the polymeric chains of 1 with di-EO azido bridging mode, whereas five and six coordination modes around Zn(II) centers are observed in complex 2, and the 1D system is formed via alternating single EO-azide and μ(O,O‧)-bridging carboxylate group of the isonicotinato-N-oxide molecules. The solid state luminescence properties of 1 were examined.

  16. 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.

  17. 1H NMR investigation of the hetero-association of phenanthridine dyes with Daunomycin: effect of substitution of amino with azido groups in the dye chromophore

    NASA Astrophysics Data System (ADS)

    Veselkov, Dennis A.; Karawajew, Leonid; Veselkov, Alexei N.; Davies, David B.

    1H NMR spectroscopy at 500 Mhz has been used to determine the structures and thermodynamics in aqueous salt solution of the hetero-association of Daunomycin (DAU) with a series of phenanthridine dyes having different numbers of amino/azido groups in the chromophore, together with the self-association of the phenthridine dyes under the same solution conditions (0.1 M phosphate buffer, pD 7.1, 298 K). The NMR measurements have been analyzed using statistical-thermodynamical models of both self-association and hetero- association in which no limitation is set on the size of molecular stacks. In this work the magnitudes of the self-association parameters of Ethidium Bromide (EB) and its azido-derivatives, 8-azido-Ethidium Bromide (EMB) and 3,8-diazido-Ethidium Chloride (EDC), show a successive decrease with mono- and di-substitition of the 3,8-amino groups of EB. A similar pattern is observed for the equilibrium constants for hetero-association of the phenanthridines with DAU. The thermodynamical and structural parameters of hetero-association of the phenanthridines with DAU are consistent with an intermolecular hydrogen bond between the 3,8 amino-groups of EB and the 9MeCO group of DAU contributing to the stability of the hetero-complex in aqueous solution.

  18. Photoaffinity derivative of colchicine: 6'-(4'-azido-2'-nitrophenylamino)hexanoyldeacetylcolchicine. Photolabeling and location of the colchicine-binding site on the alpha-subunit of tubulin

    SciTech Connect

    Williams, R.F.; Mumford, C.L.; Williams, G.A.; Floyd, L.J.; Aivaliotis, M.J.; Martinez, R.A.; Robinson, A.K.; Barnes, L.D.

    1985-11-05

    A photoaffinity analog of colchicine, 6-(4'-azido-2'-nitrophenylamino)hexanoyldeacetylcolchicine, was synthesized by reacting deacetylcolchicine or (TH)deacetylcochicine with N-succinimidyl-6-(4'-azido-2'-nitrophenylamino)hexanoate. Homogeneity of the photoaffinity analog was established by thin-layer chromatography and high-pressure liquid chromatography. The structure of the photoaffinity analog was determined by H and TC NMR, infrared and ultraviolet-visible spectroscopies, and elemental analysis. Binding of 6-(4'-azido-2'-nitrophenylamino)hexanoyldeacetylcolchicine to bovine renal tubulin was measured by competition with (TH)colchicine. The value of the apparent Ki for the photoaffinity analog was 0.28 microM in the concentration range of 0.8-1.2 microM of the analog. A value of 0.50 microM for the apparent Kd was measured by the direct binding of the tritiated photoaffinity analog to tubulin. The analog is slightly more potent an inhibitor of microtubule formation than colchicine. The photoaffinity analog reacted with renal tubulin upon irradiation with a mercury lamp equipped with a 420-nm cutoff filter. Spectral and radiochemical analyses of the tubulin after photolysis and dialysis have demonstrated a stoichiometric incorporation of the photoaffinity analog in the alpha-subunit of the tubulin. Covalent labeling of tubulin with the photoaffinity analog decreases the extent of (TH)colchicine binding by more than 90%.

  19. Assembly of azido- or cyano-bridged binuclear complexes containing the bulky [Mn(phen)2]2+ building block: syntheses, crystal structures, and magnetic properties.

    PubMed

    Ni, Zhong-Hai; Kou, Hui-Zhong; Zheng, Lei; Zhao, Yi-Hua; Zhang, Li-Fang; Wang, Ru-Ji; Cui, Ai-Li; Sato, Osamu

    2005-06-27

    Two new cyano-bridged heterobinuclear complexes, [Mn(II)(phen)2Cl][Fe(III)(bpb)(CN)2] x 0.5CH3CH2OH x 1.5H2O (1) and [Mn(II)(phen)2Cl][Cr(III)(bpb)(CN)2] x 2H2O (2) [phen = 1,10-phenanthroline; bpb(2-) = 1,2-bis(pyridine-2-carboxamido)benzenate], and four novel azido-bridged Mn(II) dimeric complexes, [Mn2(phen)4(mu(1,1)-N3)2][M(III)(bpb)(CN)2]2 x H2O [M = Fe (3), Cr (4), Co (5)] and [Mn2(phen)4(mu(1,3)-N3)(N3)2]BPh4 x 0.5H2O (6), have been synthesized and characterized by single-crystal X-ray diffraction analysis and magnetic studies. Complexes 1 and 2 comprise [Mn(phen)2Cl]+ and [M(bpb)(CN)2]- units connected by one cyano ligand of [M(bpb)(CN)2]-. Complexes 3-5 are doubly end-on (EO) azido-bridged Mn(II) binuclear complexes with two [M(bpb)(CN)2]- molecules acting as charge-compensating anions. However, the Mn(II) ions in complex 6 are linked by a single end-to-end (EE) azido bridging ligand with one large free BPh4(-) group as the charge-balancing anion. The magnetic coupling between Mn(II) and Fe(III) or Cr(III) in complexes 1 and 2 was found to be antiferromagnetic with J(MnFe) = -2.68(3) cm(-1) and J(MnCr) = -4.55(1) cm(-1) on the basis of the Hamiltonian H = -JS(Mn)S(M) (M = Fe or Cr). The magnetic interactions between two Mn(II) ions in 3-5 are ferromagnetic in nature with the magnetic coupling constants of 1.15(3), 1.05(2), and 1.27(2) cm(-1) (H = -JS(Mn1)S(Mn2)), respectively. The single EE azido-bridged dimeric complex 6 manifests antiferromagnetic interaction with J = -2.29(4) cm(-1) (H = -JS(Mn1)S(Mn2)). Magneto-structural correlationship on the EO azido-bridged Mn(II) dimers has been investigated. PMID:15962981

  20. Effect of 3'-azido-3'-deoxythymidine on human immunodeficiency virus type 1 replication in human fetal brain macrophages.

    PubMed Central

    Geleziunas, R; Arts, E J; Boulerice, F; Goldman, H; Wainberg, M A

    1993-01-01

    We investigated whether cells derived from the fetal central nervous system can support productive infection by a human immunodeficiency virus type 1 (HIV-1) isolate termed UHC-1, produced by a cellular clone derived from HIV-1 strain HIV-IIIB chronically infected U-937 promonocytic cells, and what the effect of nucleoside analogs might be on viral replication in this system. Fractionation of human fetal brain tissue into two different populations, enriched for either astrocytes or macrophages, showed that only the latter were able to support productive UHC-1 replication and generation of detectable progeny virus. Pretreatment of fetal brain macrophages with either of two nucleoside analogs, 3'-azido-3'-deoxythymidine (AZT) or the (-) enantiomer of 2'-deoxy-3'-thiacytidine, efficiently blocked production of progeny virus. Generation of unintegrated proviral DNA and HIV-1 transcripts were inhibited by pretreatment of fetal brain macrophages with 1 microM AZT. Administration of AZT at 24 h postinfection led to a slight reduction in viral transcript levels and viral progeny production by day 15 postinfection; however, brain macrophages under these conditions did not contain detectable amounts of unintegrated viral DNA. These results suggest that AZT may interfere with the accumulation of unintegrated HIV-1 DNA in brain macrophages. This is the first demonstration that nucleoside analogs are able to block HIV-1 replication in primary cultures of brain cells. Images PMID:8392310

  1. Clinical pharmacokinetics of 3'-azido-3'-deoxythymidine (zidovudine) and catabolites with formation of a toxic catabolite, 3'-amino-3'-deoxythymidine.

    PubMed

    Stagg, M P; Cretton, E M; Kidd, L; Diasio, R B; Sommadossi, J P

    1992-06-01

    This study investigated pharmacokinetics and metabolism of 3'-azido-3'-deoxythymidine (zidovudine) in patients after a 1-hour intravenous infusion of 2.5 mg/kg zidovudine with a radiolabeled tracer amount of [5-3H]-zidovudine. In addition to unchanged drug and its 5'-O-glucuronide (zidovudine glucuronide), two novel catabolites of zidovudine were detected as 3'-amino-3'-deoxythymidine (AMT), and its 5'-O-glucuronide (GAMT). The AMT apparent plasma elimination half-life (2.70 +/- 0.7 hours) was longer than that of zidovudine (1.20 +/- 0.30 hours) and zidovudine glucuronide (1.60 +/- 0.5 hours). The zidovudine/AMT plasma peak concentration and area under the concentration-time curve ratios were approximately 8 and 5, respectively. Urinary recovery of radioactivity was essentially complete within 24 hours. AMT glucuronide was not detected in urine or plasma, and only low levels of this catabolite were detected in bile. In contrast, AMT was not detected in bile. The substantial levels of AMT in the plasma of patients after zidovudine administration suggests that this catabolite may affect the pharmacodynamic properties of zidovudine in relation to its activity against human immunodeficiency virus replication and cytotoxicity to host cells. PMID:1611806

  2. 3'-Azido-3'-deoxythmidine uptake into isolated rat liver mitochondria and impairment of ADP/ATP translocator.

    PubMed

    Barile, M; Valenti, D; Passarella, S; Quagliariello, E

    1997-04-01

    To gain some insight into the mechanism by which 3'-azido-3'-deoxythymidine (AZT) impairs mitochondrial metabolism, [14C]AZT uptake by rat liver mitochondria (RLM) in vitro was investigated. AZT accumulated in mitochondria in a time-dependent manner and entered the mitochondrial matrix. The rate of AZT uptake into mitochondria showed a hyperbolic dependence on the drug concentration and was inhibited by mersalyl, a thiol reagent that cannot enter mitochondria, thus showing that a membrane protein is involved in AZT transport. Investigation into the capability of AZT to affect certain mitochondrial carriers demonstrated that AZT was able to impair the ADP/ATP translocator, but had no effect on Pi, dicarboxylate, tricarboxylate, or oxodicarboxylate carriers. AZT inhibited ADP/ATP antiport in either mitochondria or mitoplasts in a competitive manner with different sensitivity (Ki values were 18.3 +/- 2.9 and 70.2 +/- 5.8 microM, respectively). Consistent with this were isotopic measurements showing that AZT accumulates in the intermembrane space. AZT does not use ADP/ATP carrier to enter mitochondria, as shown by the failure of both carboxyatractyloside (CAT) to inhibit AZT transport into mitochondria and AZT to induce ATP efflux from ATP-loaded mitochondria. ADP/ATP translocator impairment by AZT as one of the biochemical processes responsible for the ATP deficiency syndrome is discussed. PMID:9174103

  3. 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

  4. 2-Azido-1-(3,6-dichloro-9H-fluoren-1-yl)ethanone

    PubMed Central

    Fun, Hoong-Kun; Chia, Tze Shyang; Kayarmar, Reshma; Dinesha; Nagaraja, G. K.

    2011-01-01

    In the title compound, C15H9Cl2N3O, an intra­molecular C—H⋯O inter­action generates an S(7) ring motif. The cyclo­penta-1,3-diene ring forms dihedral angles of 1.93 (6) and 2.78 (6)° with its attached benzene rings. In the crystal, mol­ecules are linked by C—H⋯N and C—H⋯O hydrogen bonds, thereby forming layers lying parallel to the ac plane. The crystal also features a π–π inter­action with a centroid–centroid distance of 3.5612 (6) Å. PMID:22058777

  5. Par-4 dependent modulation of cellular β-catenin by medicinal plant natural product derivative 3-azido Withaferin A.

    PubMed

    Amin, Hina; Nayak, Debasis; Ur Rasool, Reyaz; Chakraborty, Souneek; Kumar, Anmol; Yousuf, Khalid; Sharma, Parduman Raj; Ahmed, Zabeer; Sharma, Neelam; Magotra, Asmita; Mukherjee, Debaraj; Kumar, Lekha Dinesh; Goswami, Anindya

    2016-05-01

    Here, we provide evidences that natural product derivative 3-azido Withaferin A (3-AWA) abrogated EMT and invasion by modulating β-catenin localization and its transcriptional activity in the prostate as well as in breast cancer cells. This study, for the first time, reveals 3-AWA treatment consistently sequestered nuclear β-catenin and augmented its cytoplasmic pool as evidenced by reducing β-catenin transcriptional activity in these cells. Moreover, 3-AWA treatment triggered robust induction of pro-apoptotic intracellular Par-4, attenuated Akt activity and rescued Phospho-GSK3β (by Akt) to promote β-catenin destabilization. Further, our in vitro studies demonstrate that 3-AWA treatment amplified E-cadherin expression along with sharp downregulation of c-Myc and cyclin D1 proteins. Strikingly, endogenous Par-4 knock down by siRNA underscored 3-AWA mediated inhibition of nuclear β-catenin was Par-4 dependent and suppression of Par-4 activity, either by Bcl-2 or by Ras transfection, restored the nuclear β-catenin level suggesting Par-4 mediated β-catenin regulation was not promiscuous. In vivo results further demonstrated that 3-AWA was effective inhibitor of tumor growth and immunohistochemical studies indicated that increased expression of total β-catenin and decreased expression of phospho-β-catenin and Par-4 in breast cancer tissues as compared to normal breast tissue suggesting Par-4 and β-catenin proteins are mutually regulated and inversely co-related in normal as well as cancer condition. Thus, strategic regulation of intracellular Par-4 by 3-AWA in diverse cancers could be an effective tool to control cancer cell metastasis. Conclusively, this report puts forward a novel approach of controlling deregulated β-catenin signaling by 3-AWA induced Par-4 protein. © 2015 Wiley Periodicals, Inc. PMID:25969134

  6. 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. PMID:26881993

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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%. PMID:21306165

  13. Photoaffinity labeling of serum vitamin D binding protein by 3-deoxy-3-azido-25-hydroxyvitamin D/sub 3/

    SciTech Connect

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

    1986-05-01

    3-Deoxy-3-azido-25-hydroxyvitamin D/sub 3/ (3-Az-25-OH-D/sub 3/) was covalently incorporated into the 25-hydroxyvitamin D/sub 3/ (25-OH-D/sub 3/) binding site of purified human serum vitamin D binding protein (hDBP). Competition experiments showed that 3-Az-25-OH-D/sub 3/ and 25-OH-D/sub 3/ bound at the same site. A K/sub I/ of 80 nM was determined from 3-Az-25-OH-D/sub 33/ inhibition of 25-OH-D/sub 3/ binding to hDBP. 3-Az-25-OH-(26,27-/sup 3/H)D/sub 3/, prepared from 25-OH-(26,27-/sup 3/H)D/sub 3/, bound reversibly to hDBP in the dark. Scatchard analysis of the data indicated a single class of sites with a K/sub D. app/ of 0.71 nM and a B/sub max/ of 0.11 nM for 3-Az-25-OH-(26,27-/sup 3/H)D/sub 3/ as compared to a K/sub D. app/ of 0.37 nM and a B/sub max/ of 0.43 nM for 25-OH-(26,27-/sup 3/H)D/sub 3/. The stability of 25-OH-D/sub 3/ binding to hDBP was tested under the UV irradiation conditions required for photoactivation of 3-Az-25-OH-D/sub 3/. After 3 minutes of medium intensity, short wavelength (254 nm) UV irradiation, 40-50% of the previously bound 25-OH-(26,27-/sup 3/H)D/sub 3/ was retained by hDBP and 60% of the unliganded protein was capable of subsequently binding 25-OH-(26,27-/sup 3/H)D/sub 3/. Maximum specific covalent incorporation of 3-Az-25-OH-(26,27-/sup 3/H)D/sub 3/ by hDBP was after 3 to 5 minutes of irradiation. As much as 7.5% of the initially reversibly bound 3-Az-25-OH-(26,27-/sup 3/H)D/sub 3/ could be covalently bound to the 25-OH-D/sub 3/ binding site of hDBP.

  14. Identification of the uridine 5'-diphosphoglucose (UDP-Glc) binding subunit of cellulose synthase in Acetobacter xylinum using the photoaffinity probe 5-azido-UDP-Glc

    SciTech Connect

    Lin, F.C.; Brown, R.M. Jr.; Drake, R.R. Jr.; Haley, B.E. )

    1990-03-25

    Photoaffinity labeling of purified cellulose synthase with (beta-32P)5-azidouridine 5'-diphosphoglucose (UDP-Glc) has been used to identify the UDP-Glc binding subunit of the cellulose synthase from Acetobacter xylinum strain ATCC 53582. The results showed exclusive labeling of an 83-kDa polypeptide. Photoinsertion of (beta-32P)5-azido-UDP-Glc is stimulated by the cellulose synthase activator, bis-(3'----5') cyclic diguanylic acid. Addition of increasing amounts of UDP-Glc prevents photolabeling of the 83-kDa polypeptide. The reversible and photocatalyzed binding of this photoprobe also showed saturation kinetics. These studies demonstrate that the 83-kDa polypeptide is the catalytic subunit of the cellulose synthase in A. xylinum strain ATCC 53582.

  15. 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.

  16. 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.

  17. 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. PMID:22622667

  18. Plant cell wall imaging by metabolic click-mediated labelling of rhamnogalacturonan II using azido 3-deoxy-D-manno-oct-2-ulosonic acid.

    PubMed

    Dumont, Marie; Lehner, Arnaud; Vauzeilles, Boris; Malassis, Julien; Marchant, Alan; Smyth, Kevin; Linclau, Bruno; Baron, Aurélie; Mas Pons, Jordi; Anderson, Charles T; Schapman, Damien; Galas, Ludovic; Mollet, Jean-Claude; Lerouge, Patrice

    2016-02-01

    In plants, 3-deoxy-d-manno-oct-2-ulosonic acid (Kdo) is a monosaccharide that is only found in the cell wall pectin, rhamnogalacturonan-II (RG-II). Incubation of 4-day-old light-grown Arabidopsis seedlings or tobacco BY-2 cells with 8-azido 8-deoxy Kdo (Kdo-N3 ) followed by coupling to an alkyne-containing fluorescent probe resulted in the specific in muro labelling of RG-II through a copper-catalysed azide-alkyne cycloaddition reaction. CMP-Kdo synthetase inhibition and competition assays showing that Kdo and D-Ara, a precursor of Kdo, but not L-Ara, inhibit incorporation of Kdo-N3 demonstrated that incorporation of Kdo-N3 occurs in RG-II through the endogenous biosynthetic machinery of the cell. Co-localisation of Kdo-N3 labelling with the cellulose-binding dye calcofluor white demonstrated that RG-II exists throughout the primary cell wall. Additionally, after incubating plants with Kdo-N3 and an alkynated derivative of L-fucose that incorporates into rhamnogalacturonan I, co-localised fluorescence was observed in the cell wall in the elongation zone of the root. Finally, pulse labelling experiments demonstrated that metabolic click-mediated labelling with Kdo-N3 provides an efficient method to study the synthesis and redistribution of RG-II during root growth. PMID:26676799

  19. Site-Specific Reduction of Oxidative and Lipid Metabolism in Adipose Tissue of 3′-Azido-3′-Deoxythymidine-Treated Rats▿

    PubMed Central

    Deveaud, Catherine; Beauvoit, Bertrand; Reynaud, Annabel; Bonnet, Jacques

    2007-01-01

    Although it is well accepted that treatment with some nucleoside reverse transcriptase inhibitors modifies both fat metabolism and fat distribution in humans, the mechanisms underlying these modifications are not yet known. The present investigation examined whether a decrease in oxidative capacity, induced by a chronic oral administration of 3′-azido-3′-deoxythymidine (AZT) in rats, could be associated with an alteration of the lipogenic capacity of white adipose tissues. The impact of obesity as a factor was then evaluated. Results showed that AZT treatment induced differential effects depending on anatomical localization. Indeed, in the inguinal adipose tissue, the specific activities of cytochrome c oxidase and fatty acid synthase, two rate-controlling enzymes in energy and lipogenic metabolisms, respectively, both decreased under AZT treatment, thus leading to a lowered cell lipid accumulation. Moreover, the AMP-activated protein kinase phosphorylation level tended to increase, thus implying that AZT causes an energy imbalance. Furthermore, the inguinal tissue of obese rats presented a sensitivity to AZT treatment that was higher than that of lean rats. In contrast, for epididymal tissue, no significant change in all these parameters could be detected under AZT treatment, regardless of the nutritional status of the animals. Taken together, these data demonstrate differential effects of AZT on subcutaneous adipose tissue and visceral white adipose tissue. It could be considered that the chronic decreases in energy and lipogenic metabolism of inguinal adipocyte, consecutive to AZT treatment, may lead, in the long term, to adipose tissue atrophy. PMID:17158934

  20. 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

  1. 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

  2. Inhibition of phosphate transport in rat heart mitochondria by 3'-azido-3'-deoxythymidine due to stimulation of superoxide anion mitochondrial production.

    PubMed

    Valenti, Daniela; Atlante, Anna; Barile, Maria; Passarella, Salvatore

    2002-07-15

    In order to gain some insight into the mechanism by which 3'-azido-3'-deoxythymidine (AZT) damages mitochondria, we investigated whether externally added AZT can stimulate reactive oxygen species (ROS) production by rat heart mitochondria (RHM). An increase in superoxide anion ((O(2)(.-)) production was measured in RHM added with AZT, by using a photometrically method which allows an early O(2)(.-) detection by following the absorbance increase at 550 nm due to the ferricytochrome c reduction. Such an increase was found to be prevented from externally added superoxide dismutase. The stimulation of O(2)(.-) mitochondrial production induced by AZT was found to occur under conditions in which mitochondrial oxygen consumption was prevented by both inhibitors of electron flow and ATP synthesis. Since ROS can cause mitochondrial carrier impairment, we investigated whether AZT can affect mitochondrial permeability in virtue of its capability to stimulate ROS production. In this regard, we studied the transport of phosphate (P(i)), by measuring the mitochondrial shrinkage that takes place as a result of P(i) uptake by RHM previously swollen in a calcium acetate medium. As a result of the AZT-dependent O(2)(.-) production, uncompetitive inhibition of the rate of P(i) transport in RHM was found (K(i) of about 10 microM), consistently, such an inhibition was found to prevent by certain known ROS scavengers, i.e. superoxide dismutase, the antioxidant Vitamin C and reduced gluthatione. PMID:12123740

  3. A series of transition metal-azido extended complexes with various anionic and neutral co-ligands: synthesis, structure and their distinct magnetic behavior.

    PubMed

    Sengupta, Oindrila; Gole, Bappaditya; Mukherjee, Sandip; Mukherjee, Partha Sarathi

    2010-08-28

    The crystal structures and magnetic properties of five new transition metal-azido complexes with two anionic [pyrazine-2-carboxylate (pyzc) and p-aminobenzoate (paba)] and two neutral [pyrazine (pyz) and pyridine (py)] coligands are reported. All five complexes were synthesized by solvothermal methods. The complex [Co2(pyzc)2(N3)2(H2O)2]n (1) is 1D and exhibit canted antiferromagnetism, while the 3D complex [MnNa(pyzc)(N3)2(H2O)2]n (2) has a complicated structure and is weakly ferromagnetic in nature. [Mn2(paba)2(N3)2(H2O)2]n (3), is a 2D sheet and the MnII ions are found to be antiferromagnetically coupled. The isostructural 2D complexes [Cu3(pyz)2(N3)6]n (4) and [Cu3(py)2(N3)6]n (5) resemble remarkably in their magnetic properties exhibiting moderately strong ferromagnetism. Density functional theory calculations (B3LYP functional) have been performed to provide a qualitative theoretical interpretation of the overall magnetic behavior shown by these complexes. PMID:20623057

  4. 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

  5. 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.

  6. 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

  7. 3'-Azido-3'-deoxythymidine resistance suppressed by a mutation conferring human immunodeficiency virus type 1 resistance to nonnucleoside reverse transcriptase inhibitors.

    PubMed Central

    Larder, B A

    1992-01-01

    Nonnucleoside reverse transcriptase (NNRT) inhibitors (R82913; (+)-S-4,5,6,7-tetrahydro-9-chloro-5-methyl-6-(3-methyl-2-butenyl)- imidazo[4,5,1-jk][1,4]-benzodiazepin-2(1H)-thione; Cl-TIBO; and BI-RG-587, nevirapine) were used to select resistant human immunodeficiency virus type 1 (HIV-1) variants by passage in cell cultures of wild-type or 3'-azido-3'-deoxythymidine (zidovudine; AZT)-resistant strains. Similar to other NNRT inhibitors, Cl-TIBO induced a single mutation (Y181 to C) in reverse transcriptase (RT) that accounted for the resistance. BI-RG-587 induced a different mutation (V106-->A) in AZT resistance backgrounds. A series of viable HIV-1 variants was constructed by site-directed mutagenesis of the RT, which harbored multiple drug resistance mutations, including Y181 to C. HIV-1 that was co-resistant to NNRT inhibitors and 2',3'-dideoxyinosine resulted when a 2',3'-dideoxyinosine resistance mutation (L74 to V) was also present in RT. By contrast, however, the Y181 to C mutation in an AZT resistance background significantly suppressed resistance to AZT, while it conferred resistance to NNRT inhibitors. However, the V106-->A substitution did not cause suppression of preexisting AZT resistance. Since certain combinations of nucleoside analogs and NNRT inhibitors might result in the development of co-resistance, careful analysis of clinical isolates obtained during combination therapy will be needed to determine the potential significance of these observations. PMID:1282792

  8. 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.

  9. 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

  10. Compound matrices

    NASA Astrophysics Data System (ADS)

    Kravvaritis, Christos; Mitrouli, Marilena

    2009-02-01

    This paper studies the possibility to calculate efficiently compounds of real matrices which have a special form or structure. The usefulness of such an effort lies in the fact that the computation of compound matrices, which is generally noneffective due to its high complexity, is encountered in several applications. A new approach for computing the Singular Value Decompositions (SVD's) of the compounds of a matrix is proposed by establishing the equality (up to a permutation) between the compounds of the SVD of a matrix and the SVD's of the compounds of the matrix. The superiority of the new idea over the standard method is demonstrated. Similar approaches with some limitations can be adopted for other matrix factorizations, too. Furthermore, formulas for the n - 1 compounds of Hadamard matrices are derived, which dodge the strenuous computations of the respective numerous large determinants. Finally, a combinatorial counting technique for finding the compounds of diagonal matrices is illustrated.

  11. 5'-Azido-[3,6-3H2]-1-napthylphthalamic acid, a photoactivatable probe for naphthylphthalamic acid receptor proteins from higher plants: identification of a 23-kDa protein from maize coleoptile plasma membranes.

    PubMed Central

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

    1992-01-01

    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, we have synthesized a tritiated, photolabile NPA analogue, 5'-azido-[3,6-3H2]NPA ([3H2]N3NPA). 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 [3H2]N3NPA to maize plasma membrane vesicles was blocked by nonradioactive NPA but not by benzoic acid. After incubation of plasma membrane vesicles with [3H2]N3NPA and exposure to UV light, we 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-[7-3H]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. Images PMID:11607252

  12. Pre- and postexposure chemoprophylaxis: evidence that 3'-azido-3'-dideoxythymidine inhibits feline leukemia virus disease by a drug-induced vaccine response.

    PubMed Central

    Mathes, L E; Polas, P J; Hayes, K A; Swenson, C L; Johnson, S; Kociba, G J

    1992-01-01

    The benefits of postexposure 3'-azido-3'-dideoxythymidine (AZT) prophylaxis following human immunodeficiency virus exposure are unknown. We describe a comprehensive assessment of pre- and postexposure AZT therapy in the feline leukemia virus (FeLV)-cat model for AIDS which included in vitro testing, an in vivo dose-response titration, a postexposure treatment study, plasma drug concentration determinations, and evaluation of the immune response to FeLV. In in vitro studies, AZT prevented FeLV infection of a feline T-lymphoid cell line, giving 50 and 90% inhibition concentrations of 4.6 and 11.1 mM, respectively. In all of the in vivo efficacy studies, AZT was administered by continuous subcutaneous infusion for 28 days. AZT toxicity was excessive at a dosage of 120 mg/kg of body weight per day, causing acute anemia, but AZT was tolerable at 60 mg/kg/day. In preexposure studies, AZT was efficacious in preventing chronic antigenemia at a dosage of > or = 15 mg/kg/day, at which plasma AZT concentrations averaged between 0.51 and 0.81 micrograms/ml (2.13 and 3.03 microM). As a postexposure treatment, at 60 mg/kg/day, AZT prevented chronic FeLV antigenemia when treatment was started up to 96 h post-virus inoculation (p.i.), but not when treatment was started at 192 h p.i. The 4-day period between 96 and 192 h p.i. appears to be critical for establishing chronic viremia. It is presumed that the increase in virus load between 4 and 8 days p.i. was able to overwhelm the immunologic functions responsible for containment of FeLV infection, even though AZT therapy effectively controlled viremia during the treatment period. The antibody response to FeLV varied depending on the time of AZT treatment initiation relative to virus challenge.When AZT treatment was started 48 h before or 8 h after FeLV challenge, antibodies to FeLV were not detected until after AZT treatment was discontinued at 28 days p.i. Following AZT treatment, however, antibody titers rapidly increased at a

  13. Selection of mutations in the connection and RNase H domains of human immunodeficiency virus type 1 reverse transcriptase that increase resistance to 3'-azido-3'-dideoxythymidine.

    PubMed

    Brehm, Jessica H; Koontz, Dianna; Meteer, Jeffrey D; Pathak, Vinay; Sluis-Cremer, Nicolas; Mellors, John W

    2007-08-01

    Recent work indicates that mutations in the C-terminal domains of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) increase 3'-azido-3'-dideoxythymidine (AZT) resistance. Because it is not known whether AZT selects for mutations outside of the polymerase domain of RT, we carried out in vitro experiments in which HIV-1(LAI) or AZT-resistant HIV-1(LAI) (M41L/L210W/T215Y) was passaged in MT-2 cells in increasing concentrations of AZT. The first resistance mutations to appear in HIV-1(LAI) were two polymerase domain thymidine analog mutations (TAMs), D67N and K70R, and two novel mutations, A371V in the connection domain and Q509L in the RNase H domain, that together conferred up to 90-fold AZT resistance. Thereafter, the T215I mutation appeared but was later replaced by T215F, resulting in a large increase in AZT resistance ( approximately 16,000-fold). Mutations in the connection and RNase H domains were not selected starting with AZT-resistant virus (M41L/L210W/T215Y). The roles of A371V and Q509L in AZT resistance were confirmed by site-directed mutagenesis: A371V and Q509L together increased AZT resistance approximately 10- to 50-fold in combination with TAMs (M41L/L210W/T215Y or D67N/K70R/T215F) but had a minimal effect without TAMs (1.7-fold). A371V and Q509L also increased cross-resistance with TAMs to lamivudine and abacavir, but not stavudine or didanosine. These results provide the first evidence that mutations in the connection and RNase H domains of RT can be selected in vitro by AZT and confer greater AZT resistance and cross-resistance to nucleoside RT inhibitors in combination with TAMs in the polymerase domain. PMID:17507476

  14. 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.

  15. 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.

  16. 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.

  17. Magnesium compounds

    USGS Publications Warehouse

    Kramer, D.A.

    2001-01-01

    Seawater and natural brines accounted for about 63% of US magnesium compounds production during 2000. Premier Services in Florida, Dow Chemical in Michigan, Martin Marietta Magnesia Specialties, and Rohm & Haas recovered dead-burned and caustic-calcined magnesias from seawater. And Premier Services' recoveries, in Nevada, were from magnasite.

  18. 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. PMID:20941730

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. High-Performance Energetic Characteristics and Magnetic Properties of a Three-Dimensional Cobalt(II) Metal-Organic Framework Assembled with Azido and Triazole.

    PubMed

    Liu, Xiangyu; Qu, Xiaoni; Zhang, Sheng; Ke, Hongshan; Yang, Qi; Shi, Quan; Wei, Qing; Xie, Gang; Chen, Sanping

    2015-12-01

    A three-dimensional metal-organic framework based, high-energy-density compound, [Co5(3-atrz)7(N3)3] (3-atrz = 3-amine-1H-1,2,4-triazole), features superior detonation properties, insensitivity, and thermostability. Magnetic studies show that the compound characterizes the coexistence of remarkable coercivity, metamagnetism, long-range ordering, and relaxation dynamics. The heat-capacity measurement confirms the typical long-range antiferromagnetic ordering below 16 K. This difunctional system exemplifies an effective attempt at developing advanced magnetoenergetic materials. PMID:26599690

  11. Click chemistry oligomerisation of azido-alkyne-functionalised galactose accesses triazole-linked linear oligomers and macrocycles that inhibit Trypanosoma cruzi macrophage invasion

    PubMed Central

    Campo, Vanessa L.; Ivanova, Irina M.; Carvalho, Ivone; Lopes, Carla D.; Carneiro, Zumira A.; Saalbach, Gerhard; Schenkman, Sergio; da Silva, João Santana; Nepogodiev, Sergey A.; Field, Robert A.

    2015-01-01

    Reaction of 2-(2-(2-azidoethoxy)ethoxy)ethyl 6-O-(prop-2-ynyl)-β-d-galactopyranoside (7) under CuAAC conditions gives rise to mixed cyclic and linear triazole-linked oligomers, with individual compounds up to d.p. 5 isolable, along with mixed larger oligomers. The linear compounds resolve en bloc from the cyclic materials by RP HPLC, but are separable by gel permeation chromatography. The triazole-linked oligomers—pseudo-galactooligomers—were demonstrated to be acceptor substrates for the multi-copy cell surface trans-sialidase of the human parasite Trypanosoma cruzi. In addition, these multivalent TcTS ligands were able to block macrophage invasion by T. cruzi. PMID:26435551

  12. Modulation of the cytotoxicity of 3'-azido-3'-deoxythymidine and methotrexate after transduction of folate receptor cDNA into human cervical carcinoma: identification of a correlation between folate receptor expression and thymidine kinase activity.

    PubMed

    Sun, X L; Jayaram, H N; Gharehbaghi, K; Li, Q J; Xiao, X; Antony, A C

    1999-02-15

    Cervical carcinoma is an AIDS-defining illness. The expression of folate receptors (FRs) in cervical carcinoma (HeLa-IU1) cells was modulated by stable transduction of FR cDNA encapsidated in recombinant adeno-associated virus-2 in the sense and antisense orientation (sense and antisense cells, respectively). Although sense cells proliferated slower than antisense or untransduced cells in vivo and in vitro in 2% (but not 10%) FCS, [methyl-3H]thymidine incorporation into DNA was significantly increased in sense cells in 10% serum; therefore, the basis for this discrepancy was investigated. The activity of thymidine kinase (TK) was subsequently directly correlated with the extent of FR expression in single cell-derived clones of transduced cells. This elevated TK activity was not a result of recruitment of the salvage pathway based on the presence of adequate dTTP pools, normal thymidylate synthase (TS) activity, persistence of increased thymidine incorporation despite the exogenous provision of excess 5,10-methylene-tetrahydrofolate, and documentation of adequate folates in sense cells. The increase in TK activity conferred significant biological properties to sense cells (but not antisense or untransduced cells) as demonstrated by augmented phosphorylation of 3'-azido-3'-deoxythymidine (AZT) and concomitantly greater sensitivity to the cytotoxic effects of AZT. Conversely, sense cells were highly resistant to methotrexate, but this was reversed by the addition of AZT. The direct correlation of FR expression and TK activity indicates a previously unrecognized consequence of FR overexpression. PMID:10029088

  13. 1,3-Dipolar Cycloadditions of Diazo Compounds in the Presence of Azides.

    PubMed

    Aronoff, Matthew R; Gold, Brian; Raines, Ronald T

    2016-04-01

    The diazo group has untapped utility in chemical biology. The tolerance of stabilized diazo groups to cellular metabolism is comparable to that of azido groups. However, chemoselectivity has been elusive, as both groups undergo 1,3-dipolar cycloadditions with strained alkynes. Removing strain and tuning dipolarophile electronics yields diazo group selective 1,3-dipolar cycloadditions that can be performed in the presence of an azido group. For example, diazoacetamide but not its azido congener react with dehydroalanine residues, as in the natural product nisin. PMID:26981746

  14. Synthesis and Evaluation of Self-Assembled Azido Monolayer as a Novel Dielectric Layer for Fabricating Pentacene-Based Organic Thin Film Transistors.

    PubMed

    Yeh, Je-Yuan; Tsai, Tzung-Da; Kuo, An Tsung; Chou, Ying-Shiun; Liou, Ying-Shian; Chang, Zhao-You; Tsiang, Raymond Chien-Chao; Guo, Tzung-Fang; Chang, Chien-Hsiang

    2015-05-01

    Self-assembled 3-azidopropyltriethoxysilane monolayer (SAM) is used as a dielectric layer to modify the interface between the silicon dioxide wafer and the pentacene semiconductor layer in an organic thin film transistor (OTFT), Au/pentacene/3-azidopropyltriethoxysilane/SiO2/Si. Compared to the commonly used alkyl siliane C18 dielectric, 3-azidopropyltriethoxysilane which possesses stable formal charges is far more effective in increasing the ON/OFF ratio of OTFT device with an improvement of nearly three orders of magnitude. Analysis and measurements reported in this paper have illustrated for the first time the improvement of OTFT performance by a SAM compound with stable formal charges. PMID:26504992

  15. 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

  16. Intrastrand cross-linked actin between Gln-41 and Cys-374. I. Mapping of sites cross-linked in F-actin by N-(4-azido-2-nitrophenyl) putrescine.

    PubMed

    Hegyi, G; Mák, M; Kim, E; Elzinga, M; Muhlrad, A; Reisler, E

    1998-12-22

    A new heterobifunctional photo-cross-linking reagent, N-(4-azido-2-nitrophenyl)-putrescine (ANP), was synthesized and covalently bound to Gln-41 of rabbit skeletal muscle actin by a bacterial transglutaminase-mediated reaction. Up to 1.0 mol of the reagent was incorporated per mole of G-actin; at least 90% of it was bound to Gln-41 while a minor fraction (about 8%) was attached to Gln-59. The labeled G-actin was polymerized, and the resulting F-actin was intermolecularly cross-linked by irradiation with UV light. The labeled and cross-linked peptides were isolated from either a complete or limited tryptic digest of cross-linked actin. In the limited digest the tryptic cleavage was restricted to arginine by succinylation of the lysyl residues. N-terminal sequencing and mass spectrometry indicated that the cross-linked peptides contained residues 40-50 (or 40-62 in the arginine limited digest) and residues 373-375, and that the actual cross-linking took place between Gln-41 and Cys-374. This latter finding was also supported by the inhibition of Cys-374 labeling with a fluorescent probe in the cross-linked actin. The dynamic length of ANP, between 11.1 and 12.5 A, constrains to that range the distance between the gamma-carboxyl group of Gln-41 in one monomer and the sulfur atom of Cys-374 in an adjacent monomer. This is consistent with the distances between these two residues on adjacent monomers of the same strand in the long-pitch helix in the structural models of F-actin [Holmes, K. C., Popp, D., Gebhard, W., and Kabsch, W. (1990) Nature 347, 44-49 and Lorenz, M., Popp, D., and Holmes, K. C. (1993) J. Mol. Biol. 234, 826-836]. The effect of cross-linking on the function of actin is described in the companion papers. PMID:9922144

  17. 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

  18. Compounding in Ukraine.

    PubMed

    Zdoryk, Oleksandr A; Georgiyants, Victoriya A; Gryzodub, Oleksandr I; Schnatz, Rick

    2013-01-01

    Pharmaceutical compounding in modern Ukraine has a rich history and goes back to ancient times. Today in the Ukraine, there is a revival of compounding practice, the opening of private compounding pharmacies, updating of legislative framework and requirements of the State Pharmacopeia of Ukraine for compounding preparations, and the introduction of Good Pharmaceutical Practice. PMID:23696172

  19. 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

  20. 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.

  1. 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

  2. Caulking compound poisoning

    MedlinePlus

    Caulking compounds are substances used to seal cracks and holes around windows and other openings. Caulking compound poisoning occurs when someone swallows these substances. This is for information only and not for use in the ...

  3. Structure-activity and cross-resistance evaluations of a series of human immunodeficiency virus type-1-specific compounds related to oxathiin carboxanilide.

    PubMed Central

    Buckheit, R W; Kinjerski, T L; Fliakas-Boltz, V; Russell, J D; Stup, T L; Pallansch, L A; Brouwer, W G; Dao, D C; Harrison, W A; Schultz, R J

    1995-01-01

    A series of compounds related to the nonnucleoside reverse transcriptase (RT) inhibitor (NNRTI) oxathiin carboxanilide (UC84) were evaluated for activity against the human immunodeficiency virus (HIV) to determine structural requirements for anti-HIV activity. Twenty-seven compounds representative of the more than 400 Uniroyal Chemical Company (UC) compounds were evaluated for structure-activity relationships. Several of the compounds evaluated were highly active, with 50% effective concentrations in the nanomolar range and therapeutic indices of > 1,000. Highly synergistic anti-HIV activity was observed for each compound when used in combination with 3'-azido-3'-deoxythymidine; additive to slightly synergistic interactions were observed with the compounds used in combination with dideoxycytidine. In combination with the NNRTI costatolide, only UC38 synergistically inhibited HIV type 1. Residues in the RT which, when mutated, impart resistance to the virus isolates selected in cell culture, against virus variants with site-directed mutations, and against RTs containing defined single amino acid changes. The mutations included changes in RT amino acids 100, 101, 103, 106, 108, and 181. The results with isolates selected in cell culture indicate that the carboxanilide compounds interact with the RT at two vulnerable sites, selecting UC-resistant virus isolates with the Y-to-C mutation at position 181 (Y181C) or the L100I substitution. A resistant virus isolate containing both Y181C combination with calanolide A, an NNRTI which retains activity against virus with the single Y181C mutation, UC10 rapidly selected a virus isolate with the K103N mutation. The merits of selecting potential candidate anti-HIV agents to be used in rational combination drugs design as part of an armamentarium of highly active anti-HIV compounds are discussed. PMID:8593008

  4. Production of epoxy compounds from olefinic compounds

    SciTech Connect

    Gelbein, A.P.; Kwon, J.T.

    1985-01-29

    Chlorine and tertiary alkanol dissolved in an inert organic solvent are reacted with aqueous alkali to produce tertiary alkyl hypochlorite which is recovered in the organic solvent and reacted with water and olefinically unsaturated compound to produce chlorohydrin and tertiary alkanol. Chlorohydrin and tertiary alkanol recovered in the organic solvent are contacted with aqueous alkali to produce the epoxy compound, and tertiary alkanol recovered in the organic solvent is recycled to hypochlorite production. The process may be integrated with the electrolytic production of chlorine, with an appropriate treatment of the recycle aqueous stream when required.

  5. 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/

  6. Ecotoxicology of organofluorous compounds.

    PubMed

    Murphy, Margaret B; Loi, Eva I H; Kwok, Karen Y; Lam, Paul K S

    2012-01-01

    Organofluorous compounds have been developed for myriad purposes in a variety of fields, including manufacturing, industry, agriculture, and medicine. The widespread use and application of these compounds has led to increasing concern about their potential ecological toxicity, particularly because of the stability of the C-F bond, which can result in chemical persistence in the environment. This chapter reviews the chemical properties and ecotoxicology of four groups of organofluorous compounds: fluorinated refrigerants and propellants, per- and polyfluorinated compounds (PFCs), fluorinated pesticides, and fluoroquinolone antibiotics. These groups vary in their environmental fate and partitioning, but each raises concern in terms of ecological risk on both the regional and global scale, particularly those compounds with long environmental half-lives. Further research on the occurrence and toxicities of many of these compounds is needed for a more comprehensive understanding of their ecological effects. PMID:21952849

  7. 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.

  8. 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)

  9. Fidelity of binding of the guanidinium nucleic acid (DNG) d(Tg)4-T-azido with short strand DNA oligomers (A5G3A5, GA4G3A4G, G2A3G3A3G2, G2A2G5A2G2). A kinetic and thermodynamic study.

    PubMed

    Blaskó, A; Minyat, E E; Dempcy, R O; Bruice, T C

    1997-06-24

    Short strand DNA oligomers (A5G3A5, GA4G3A4G, G2A3G3A3G2, and G2A2G5A2G2) and the guanidinium (g) linked thymidyl nucleoside d(Tg)4-T-azido associate as triplexes. The melting temperatures, Tm, the association and dissociation kinetic and thermodynamic parameters and activation energies for the triplexes were determined by UV thermal analysis. The hypochromic shift and Tm for triplex formation increases with increase in concentration and decreases with the number of mismatches. The melting temperatures are between 35 and 55 degrees C in the range of ionic strength of 0.06-0.24 and decrease with increase in ionic strength at 100 deg/(ionic strength unit). The melting and cooling curves exhibit hysteresis behavior in the temperature range 5-95 degrees C at 0.2 deg/min thermal rate. From these curves, the rate constants and the energies of activation for association (k(on), E(on)) and dissociation (k(off), E(off)) processes were obtained. The second-order rate constants, k(on), for the triplex formation at 288 K are between 10 and 500 M(-2) s(-1). Values of k(on) increase with the decrease in the ionic strength. The first order rate constants for the dissociation, k(off), at 288 K are between 10(-6) and 40 x 10(-6) s(-1) and increase with increase in ionic strength. The energies of activation for the association and dissociation processes are in the range -22 to -9 kcal/mol and 8 to 29 kcal/mol, respectively. At 6.3 x 10(-5) M/base and at the physiological ionic strength (0.15-0.30) and below, the triplex structures formed with d(Tg)4-T-azido and A5G3A5 and GA4G3A4G have well-defined Tm values. The melting curves with G2A3G3A3G2 and G2A2G5A2G2 are very shallow with small hypochromic shifts denoting negligible binding at physiological ionic strength. Therefore, with the increase in the G content (mismatched base pairs) at a certain concentration (e.g., 6.3 x 10(-5) M/base), discrimination (change in fidelity) occurs in the formation and strength of binding of d(Tg)4-T-azido

  10. Anti-Fog Compound

    NASA Technical Reports Server (NTRS)

    1985-01-01

    Tracer Chemical Corporation's TRX Anti-Fog Composition is an inexpensive product which prevents condensation on plastic and glass surfaces. It was the result from a Tech Briefs article detailing a Johnson Space Center compound.

  11. 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.

  12. 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.

  13. 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.

  14. Compounding a Problem?

    PubMed

    Berlin, Joey

    2016-01-01

    Allergist-immunologists say a U.S. Pharmacopeia proposal will mess with an allergy treatment system that's worked for more than a century. The revised standards, if adopted, would remove a key exemption separating allergen extract preparations from the stricter requirements of other compounds. Immunologists say the exemption has allowed them to compound allergen extracts in their own offices, and they've done so safely and effectively millions of times a year. PMID:27175928

  15. 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.

  16. 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

  17. 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. PMID:27194882

  18. 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.

  19. Understanding medication compounding issues.

    PubMed

    Hicks, Rodney W

    2014-04-01

    The potential for contamination of compounded products and the resulting infections are a serious threat to patient safety. Immediate use products are used frequently in the perioperative department, and perioperative nurses should be familiar with the guidelines and practices that aim to reduce the contamination that can occur during the sterile compounding process. Four common themes lead to successful compounding: quality (eg, product identification, purity, stability, compatibility, risk level assessment), the environment (eg, using a segregated compounding area with specialized airflow capabilities, reducing particulate matter, practicing proper hand hygiene, performing gloved fingertip sampling, properly cleaning equipment and work areas), personnel activities (eg, familiarity with types of containers used and how often they can be accessed, following expiration dates and the number of times containers can be accessed), and the control process (eg, process monitoring, quality improvement). If a third-party vendor is contracted to handle compounding for a facility, perioperative personnel should be aware of the responsibilities for the facility and the vendor to ensure a quality compounding program. PMID:24674793

  20. 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.

  1. 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.

  2. 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. PMID:19502566

  3. 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

  4. 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.

  5. Analyzing cranberry bioactive compounds.

    PubMed

    Côté, J; Caillet, S; Doyon, G; Sylvain, J-F; Lacroix, M

    2010-10-01

    There is a growing public interest for the North American cranberry (Vaccinium macrocarpon) as a functional food because of the potential health benefits linked to phytochemical compounds present in the fruit--the anthocyanin pigments, responsible for its brilliant red color, and other secondary plant metabolites (flavonols, flavan-3-ols, proanthocyanidins, and phenolic acid derivatives). Isolation of these phenolic compounds and flavonoids from a sample matrix is a prerequisite to any comprehensive analysis scheme. By far the most widely employed analytical technique for the characterization of these compounds has been high-performance liquid chromatography(HPLC) coupled with ultraviolet-visible(UV/Vis) and mass spectrometer(MS) detection. This review covers the cranberry major bioactive compounds, the extraction and purification methods, and the analytical conditions for HPLC used to characterize them. Extraction, chromatographic separation and detection strategies, analyte determinations, and applications in HPLC are discussed and the information regarding methods of specific cranberry analyte analyses has been summarized in tabular form to provide a means of rapid access to information pertinent to the reader. PMID:20924868

  6. 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.

  7. 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...

  8. Zinc and Compounds

    Integrated Risk Information System (IRIS)

    Zinc and Compounds ; CASRN 7440 - 66 - 6 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 Noncarcinogen

  9. Boron and Compounds

    Integrated Risk Information System (IRIS)

    Boron and Compounds ; CASRN 7440 - 42 - 8 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 Noncarcinoge

  10. 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

  11. 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

  12. Beryllium and compounds

    Integrated Risk Information System (IRIS)

    Beryllium and compounds ; CASRN 7440 - 41 - 7 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 Noncarci

  13. 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

  14. 8-fluoropurine compounds

    DOEpatents

    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.

  15. 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…

  16. Aminopropyl thiophene compounds

    SciTech Connect

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

    1990-04-03

    This patent describes 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.

  17. 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…

  18. The Onium Compounds

    NASA Astrophysics Data System (ADS)

    Tsarevsky, Nicolay V.; Slaveykova, Vera; Manev, Stefan; Lazarov, Dobri

    1997-06-01

    The onium salts are of a big interest for theoretical and structural chemistry, and for organic synthesis. Some representatives of the group (e.g. ammonium salts) were known from the oldest times. Many onium salts are met the nature: ammonium salts (either as inorganic salts, and organic derivatives, e.g. aminoacids, salts of biogenic amines and alkaloids, etc.); oxonium salts (plant pigments as anthocyans are organic oxonium compounds), etc. In 1894 C. Hartmann and V. Meyer prepared the first iodonium salts - 4-iododiphenyliodonium hydrogensulfate and diphenyliodonium salts, and suggested the ending -onium for all compounds with properties similar to those of ammonium salts. Nowadays onium compounds of almost all nonmetals are synthesised and studied. A great variety of physical methods: diffraction (e.g. XRD) and spectral methods (IR-, NMR-, and UV-spectra), as well as the chemical properties and methods of preparation of onium salts have been used in determination of the structure of these compounds. The application of different onium salts is immense. Ammonium, phosphonium and sulfonium salts are used as phase-transfer catalysts; diazonium salts - for the preparation of dyes, metalochromic and pH-indicators. All the onium salts and especially diazonium and iodonium salts are very useful reagents in organic synthesis.

  19. Noun Compounding in Thai.

    ERIC Educational Resources Information Center

    Fasold, Ralph William August

    The present study, a slightly revised version of the author's 1968 Ph.D. thesis presented to the University of Chicago, investigates compound formation in Thai. Chapter 1 summarizes the transformational generative theory on which the study is based, discusses the concept that Thai is a "simple" language in comparison with English, and briefly…

  20. 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.

  1. 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. PMID:27072487

  2. Photofunctions of intercalation compounds

    SciTech Connect

    Ogawa, Makoto; Kuroda, Kazuyuki

    1995-03-01

    In this article, the authors review the studies on the photofunctions of intercalation compounds. (The structures and properties of host materials which have been used for immobilizing photoactive species have been summarized in the following section.) some of these studies are for the purpose of characterizing the properties of host materials and host-guest systems, and others are for the purpose of contributing to future practical applications. The well-defined layered structures as well as the ability to accommodate guest species on the surface of the layers are very useful for organizing photoactive species to evaluate and control the photofunctions. Table 1 summarizes the characteristics of typical host-guest systems studied for immobilizing photoactive species. Attention is mainly focused on the role of layered structure on the organization of photoactive species; the photofunctions of intercalation compounds are discussed only in connection with the microscopic structures. 321 refs.

  3. Arsonium compounds in algae

    PubMed Central

    Benson, A. A.

    1989-01-01

    Search for a precursor of the arsenobetaine discovered in Western Australian rock lobster tail muscle has led to an algal metabolite of radioarsenate having the properties of a trimethylarsoniumriboside derivative of the major arsenicals of aquatic plants, dimethylarsinoylribosylglycerol, its sulfate ester, and the corresponding riboside of phosphatidylglycerol. Such an arsonium compound could serve as metabolic precursor of arsenobetaine, the innocuous arsenical component of many marine food products. The oceanic diatom, Chaetoceros gracilis, cultured in radioarsenate produced a compound whose chemical, chromatographic, and electrophoretic properties are described. It was found to be identical to the trimethylarsonium derivative synthesized from the major algal arsenical, 1-(5′-dimethylarsinoyl-5′-deoxyribosyl)glycerol-3-O -sulfate. PMID:16594059

  4. 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.

  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. Antifungal Compounds from Cyanobacteria

    PubMed Central

    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

    2015-01-01

    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. PMID:25871291

  7. 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.

  8. 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. PMID:24214851

  9. 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.

  10. 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 ...

  11. 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

  12. 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.

  13. 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.

  14. Turbo compound engine

    SciTech Connect

    Okada, M.; Sekiyama, S.

    1988-06-07

    A turbo compound engine is described comprising: an engine having an exhaust gas passage and a crankshaft; a power turbine disposed in the exhaust gas passage so as to recover the exhaust gas energy; driving power transmission means for drivingly connecting the power turbine and the crankshaft so as to transmit the driving power; a fluid passage connected to a portion of the exhaust passage which lies between the power turbine and the engine; and fluid passage switching means for closing the exhaust passage upstream of the fluid passage while opening the fluid passage during exhaust braking.

  15. 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

  16. 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.

  17. Compound allergy. An overview.

    PubMed

    Bashir, S J; Maibach, H I

    1997-04-01

    This review defines the term "compound allergy" in the context of new findings, and discusses evidence that allergenic reaction products have been identified. Material was gathered by searching Index Medicus and the Science Citation Index, and reviewing several standard texts. Issues regarding the validity of patch test results are addressed and we introduce the term "pseudocompound allergy" to cover cases of false-negative patch tests. We present new theories regarding the mechanisms by which new allergens are formed and a means of classification. PMID:9165199

  18. Organometallic chemistry of bimetallic compounds

    SciTech Connect

    Casey, C.P.

    1991-07-01

    This report consists of six sections: heterobimetallic dihydrides, early-late transition metal heterobimetallic compounds, amphiphilic carbene complexes and hydroxycarbene complexes, diiron compounds with bridging hydrocarbon ligands, diphosphine chelates with natural bite angles near 120 degrees, and synthesis and reactions of M=M compounds. (WET)

  19. 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

  20. Turbo compound engine

    SciTech Connect

    Kawamura, H.

    1988-05-24

    A turbo compound engine having a first exhaust turbine coupled to an exhaust pipe of an internal combustion engine and a second exhaust turbine coupled to an exhaust port of the first exhaust turbine is described comprising: a first generator drivable by the first exhaust turbine; a second generator drivable by the second exhaust turbine; a motor operatively coupled to an output shaft of the internal combustion engine; speed detecting means for detecting the speed of rotation of the internal combustion engine; and control means for controlling the frequency of electric power, which is the sum of electric power outputs from the first and second generators and supplied to the motor, based on a signal from the speed detecting means, in order to control operation of the motor.

  1. Microoptical telescope compound eye

    NASA Astrophysics Data System (ADS)

    Duparré, Jacques W.; Schreiber, Peter; Matthes, André; Pshenay–Severin, Ekaterina; Bräuer, Andreas; Tünnermann, Andreas; Völkel, Reinhard; Eisner, Martin; Scharf, Toralf

    2005-02-01

    A new optical concept for compact digital image acquisition devices with large field of view is developed and proofed experimentally. Archetypes for the imaging system are compound eyes of small insects and the Gabor Superlens. A paraxial 3x3 matrix formalism is used to describe the telescope arrangement of three microlens arrays with different pitch to find first order parameters of the imaging system. A 2mm thin imaging system with 21x3 channels, 70ºx10º field of view and 4.5mm x 0.5mm image size is optimized and analyzed using sequential and non sequential raytracing and fabricated by microoptics technology. Anamorphic lenses, where the parameters are a function of the considered optical channel, are used to achieve a homogeneous optical performance over the whole field of view. Captured images are presented and compared to simulation results.

  2. Microoptical telescope compound eye.

    PubMed

    Duparré, Jacques; Schreiber, Peter; Matthes, André; Pshenay-Severin, Ekaterina; Bräuer, Andreas; Tünnermann, Andreas; Völkel, Reinhard; Eisner, Martin; Scharf, Toralf

    2005-02-01

    A new optical concept for compact digital image acquisition devices with large field of view is developed and proofed experimentally. Archetypes for the imaging system are compound eyes of small insects and the Gabor-Superlens. A paraxial 3x3 matrix formalism is used to describe the telescope arrangement of three microlens arrays with different pitch to find first order parameters of the imaging system. A 2mm thin imaging system with 21x3 channels, 70 masculinex10 masculine field of view and 4.5mm x 0.5mm image size is optimized and analyzed using sequential and non-sequential raytracing and fabricated by microoptics technology. Anamorphic lenses, where the parameters are a function of the considered optical channel, are used to achieve a homogeneous optical performance over the whole field of view. Captured images are presented and compared to simulation results. PMID:19494951

  3. 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

  4. Group-IV semiconductor compounds

    SciTech Connect

    Berding, M.A.; Sher, A.; van Schilfgaarde, M.

    1997-08-01

    Properties of ordered group-IV compounds containing carbon, silicon, and germanium are calculated within the local density approximation. Twenty-seven fully relaxed compounds represented by seven different compound structures are compared and, with the exception of SiC, all compounds are found to be metastable. Two trends emerge: carbon-germanium bonds are disfavored, and compounds that have carbon on a common sublattice are the least unbound because of their relatively low strain. When carbon shares a sublattice with silicon or germanium, the large strain results in a narrowing of the band gap, and in some cases the compound is metallic. The most promising structures with the lowest excess energy contain carbon on one sublattice and although they do not lattice match to silicon, they match rather well to silicon carbide. {copyright} {ital 1997} {ital The American Physical Society}

  5. Compound chondrules: an experimental investigation

    NASA Astrophysics Data System (ADS)

    Connolly, H. C., Jr.; Hewins, R. H.; Atre, N.; Lofgren, G. E.

    1994-07-01

    Compound chondrules are considered to be the product of collisions between molten chondrules during chondrule formation Wasson, J. T. et al. (1994) have argued that some compound chondrules are formed when a chondrule with an accretional rim experienced a flash-melting event similar to a chondrule-forming event. We have designed experiments to investigate the formation of compound chondrules by both methods. Experiments were performed on a Deltech vertical muffle tube furnace to form synthetic chondrules to use as accretion rim material. For our experimental conditions, it is clear that compound chondrules can only be made by a collisional event. Our changes maintain their spherical shape and produce distinct boundaries between charges that are similar to natural compound chondrules. Furthermore, collision event(s) between chondrules will cause nucleation if they are molten and undercooled, thus producing chondrule textures. Flash melting chondrules with accretionary rims will not produce compound chondrules but will produce new chondrules with new textures.

  6. Compounding in synthetic aperture imaging.

    PubMed

    Hansen, Jens Munk; Jensen, Jørgen Arendt

    2012-09-01

    A method for obtaining compound images using synthetic aperture data is investigated using a convex array transducer. The new approach allows spatial compounding to be performed for any number of angles without reducing the frame rate or temporal resolution. This important feature is an intrinsic property of how the compound images are constructed using synthetic aperture data and an improvement compared with how spatial compounding is obtained using conventional methods. The synthetic aperture compound images are created by exploiting the linearity of delay-and-sum beamformation for data collected from multiple spherical emissions to synthesize multiple transmit and receive apertures, corresponding to imaging the tissue from multiple directions. The many images are added incoherently, to produce a single compound image. Using a 192-element, 3.5-MHz, λ-pitch transducer, it is demonstrated from tissue-phantom measurements that the speckle is reduced and the contrast resolution improved when applying synthetic aperture compound imaging. At a depth of 4 cm, the size of the synthesized apertures is optimized for lesion detection based on the speckle information density. This is a performance measure for tissue contrast resolution which quantifies the tradeoff between resolution loss and speckle reduction. The speckle information density is improved by 25% when comparing synthetic aperture compounding to a similar setup for compounding using dynamic receive focusing. The cystic resolution and clutter levels are measured using a wire phantom setup and compared with conventional application of the array, as well as to synthetic aperture imaging without compounding. If the full aperture is used for synthetic aperture compounding, the cystic resolution is improved by 41% compared with conventional imaging, and is at least as good as what can be obtained using synthetic aperture imaging without compounding. PMID:23007781

  7. New England Compounding Center Indictment.

    PubMed

    Cabaleiro, Joe

    2015-01-01

    This article is a review of the lapses in compliance with United States Pharmacopeia standards and pharmacy law as alleged by the New England Compounding Center indictment. This indictment was a result of an outbreak of fungal meningitis traced to fungal contamination of compounded methylprednisolone suspension for epidural steroid injections. This article is also intended as a gap analysis for compounders to review compliance at their own facility, and, if necessary, take the appropriate steps to implement best practices. PMID:26685489

  8. Method of producing cyclohexasilane compounds

    SciTech Connect

    Elangovan, Arumugasamy; Anderson, Kenneth; Boudjouk, Philip R; Schulz, Douglas L

    2015-03-10

    A method of preparing a cyclohexasilane compound from trichlorosilane is provided. The method includes contacting trichlorosilane with a reagent composition to produce a compound containing a tetradecahalocyclohexasilane dianion, such as a tetradecachlorocyclohexasilane dianion. The reagent composition typically includes (a) tertiary polyamine ligand; and (b) a deprotonating reagent, such as a tertiary amine having a pKa of at least about 10.5. Methods of converting the tetradecahalocyclohexasilane dianion-containing compound to cyclohexasilane or a dodecaorganocyclohexasilane are also provided.

  9. 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.

  10. 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. PMID:26714363

  11. 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.

  12. 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.

  13. 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

  14. ATMOSPHERIC FREONS AND HALOGENATED COMPOUNDS

    EPA Science Inventory

    Ambient levels of atmospheric Freons, halogenated hydrocarbons, and SF6 were measured at various locations in the U.S.A. Compounds such as CCl3F, CCl2F2, CH3-CCl3, and CCl4 were ubiquitious and generally measured at sub ppb levels. Tropospherically reactive compounds such as C2Cl...

  15. 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

  16. 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…

  17. 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…

  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. Bilayer Effects of Antimalarial Compounds.

    PubMed

    Ramsey, Nicole B; Andersen, Olaf S

    2015-01-01

    Because of the perpetual development of resistance to current therapies for malaria, the Medicines for Malaria Venture developed the Malaria Box to facilitate the drug development process. We tested the 80 most potent compounds from the box for bilayer-mediated effects on membrane protein conformational changes (a measure of likely toxicity) in a gramicidin-based stopped flow fluorescence assay. Among the Malaria Box compounds tested, four compounds altered membrane properties (p< 0.05); MMV007384 stood out as a potent bilayer-perturbing compound that is toxic in many cell-based assays, suggesting that testing for membrane perturbation could help identify toxic compounds. In any case, MMV007384 should be approached with caution, if at all. PMID:26551613

  20. Macrocyclic compounds as corrosion inhibitors

    SciTech Connect

    Quraishi, M.A.; Rawat, J.; Ajmal, M.

    1998-12-01

    The influence of three macrocyclic compounds on corrosion of mild steel (MS) in hydrochloric acid (HCl) was investigated using weight loss, potentiodynamic polarization, alternating current (AC) impedance, and hydrogen permeation techniques. All the investigated compounds showed significant efficiencies and reduced permeation of hydrogen through MS in HCl. Inhibition efficiency (IE) varied with the nature and concentrations of the inhibitors, temperature, and concentrations of the acid solutions. The addition of iodide ions (I{sup {minus}}) increased IE of all the tested compounds as a result of the synergistic effect. Potentiodynamic polarization results revealed that macrocyclic compounds acted as mixed inhibitors in 1 M HCl to 5 M HCl. Adsorption on the metal surface obeyed Temkin`s adsorption isotherm. Auger electron spectroscopy (AES) of the polished MS surface, exposed with tetraphenyldithia-octaazacyclotetradeca-hexaene (PTAT) proved adsorption of this compound on the surface through nitrogen and sulfur atoms.

  1. Bilayer Effects of Antimalarial Compounds

    PubMed Central

    Ramsey, Nicole B.; Andersen, Olaf S.

    2015-01-01

    Because of the perpetual development of resistance to current therapies for malaria, the Medicines for Malaria Venture developed the Malaria Box to facilitate the drug development process. We tested the 80 most potent compounds from the box for bilayer-mediated effects on membrane protein conformational changes (a measure of likely toxicity) in a gramicidin-based stopped flow fluorescence assay. Among the Malaria Box compounds tested, four compounds altered membrane properties (p< 0.05); MMV007384 stood out as a potent bilayer-perturbing compound that is toxic in many cell-based assays, suggesting that testing for membrane perturbation could help identify toxic compounds. In any case, MMV007384 should be approached with caution, if at all. PMID:26551613

  2. 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

  3. Antiparasitic Compounds That Target DNA

    PubMed Central

    Wilson, W. David; Tanious, Farial A.; Mathis, Amanda; Tevis, Denise; Hall, James Edwin; Boykin, David W.

    2008-01-01

    Designed, synthetic heterocyclic diamidines have excellent activity against eukaryotic parasites that cause diseases such as sleeping sickness and leishmania and adversely affect millions of people each year. The most active compounds bind specifically and strongly in the DNA minor groove at AT sequences. The compounds enter parasite cells rapidly and appear first in the kinetoplast that contains the mitochondrial DNA of the parasite. With time the compounds are also generally seen in the cell nucleus but are not significantly observed in the cytoplasm. The kinetoplast decays over time and disappears from the mitochondria of treated cells. At this point the compounds begin to be observed in other regions of the cell, such as the acidocalcisomes. The cells typically die in 24–48 hours after treatment. Active compounds appear to selectively target extended AT sequences and induce changes in kinetoplast DNA minicircles that cause a synergistic destruction of the catenated kinetoplast DNA network and cell death. PMID:18343228

  4. 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.

  5. /sup 125/I-BW-A844U, an antagonist radioligand with high affinity and selectivity for adenosine A1 receptors, and /sup 125/I-azido-BW-A844U, a photoaffinity label

    SciTech Connect

    Patel, A.; Craig, R.H.; Daluge, S.M.; Linden, J.

    1988-06-01

    3-(4-Amino)phenethyl-1-propyl-8-cyclopentylxanthine (BW-A844U) has been synthesized and shown to bind with high affinity to adenosine A1 receptors of bovine brain membranes (KD = 0.23 nM). This compound is highly selective for A1 receptors; the KI for binding to A2 receptors of human platelet membranes is 2.0 microM (A2/A1 ratio = 8700). Radioiodination of the 3-aminophenethyl group resulted in 125I-BW-A844U, a radioligand that retains high affinity for A1 receptors in bovine brain membranes (KD = 0.14 nM) and to 3-((3-cholamidopropyl)-dimethylammonio)-1-propane sulfonate-solubilized receptors (KD = 0.34 nM). Specific binding of 125I-BW-A844U represented greater than 90% of the total binding at the KD. From the association constant (K1 = 5.0 X 10(8) M-1min-1) and the dissociation constant (K-1 = 0.064 min-1), the kinetic KD (K-1/K1) in membranes was calculated to be 0.13 nM. NaCl (1 M) had little effect on the binding affinity of 125I-BW-A844U, in contrast to the large effect of salt on the binding affinity of acidic antagonist radioligands. 8-Sulfophenyltheophylline inhibited radioligand binding with a Hill coefficient of 1.0, indicative of a single affinity binding state for the antagonist. By comparison, two distinct agonist affinity states of A1 receptors for the agonist (R)-phenylisopropyladenosine could be resolved, a high affinity state (62%, KH = 74 pM) and a low affinity state (KL = 3.83 nM). The addition of 0.1 mM guanylylimidodiphosphate converted all receptors to the low affinity state. Addition of NaCl (0.5 M) decreased the fraction of receptors in the high affinity state and increased both KH and KL, suggesting that NaCl alters coupling of receptors to G proteins and influences the conformation of the receptor polypeptide, whether or not the receptor is coupled to a G protein.

  6. 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.

  7. New syntheses of diazo compounds.

    PubMed

    Maas, Gerhard

    2009-01-01

    Diazo compounds (R1R2C=N2) are known as versatile and useful substrates for an array of chemical transformations and, therefore, diazo chemistry is still far from losing anything of its long-standing fascination. In addition to many studies on the subsequent chemistry of the diazo group, the inventory of methods for the preparation of diazo compounds is continuously supplemented by new methods and novel variations of established procedures. Several of these synthetic approaches take into account the lability and remarkable chemical reactivity of certain classes of diazo compounds, and environmentally more benign procedures also continue to be developed. PMID:19790217

  8. Regulation of Compound Leaf Development

    PubMed Central

    Wang, Yuan; Chen, Rujin

    2013-01-01

    Leaf morphology is one of the most variable, yet inheritable, traits in the plant kingdom. How plants develop a variety of forms and shapes is a major biological question. Here, we discuss some recent progress in understanding the development of compound or dissected leaves in model species, such as tomato (Solanum lycopersicum), Cardamine hirsuta and Medicago truncatula, with an emphasis on recent discoveries in legumes. We also discuss progress in gene regulations and hormonal actions in compound leaf development. These studies facilitate our understanding of the underlying regulatory mechanisms and put forward a prospective in compound leaf studies. PMID:27135488

  9. Polishing compound for plastic surfaces

    DOEpatents

    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.

  10. 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.

  11. Polishing compound for plastic surfaces

    SciTech Connect

    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.

  12. 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.

  13. Compound cuing in free recall.

    PubMed

    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 effect should be greater when the 2 most recently recalled items were studied in contiguous list positions. A meta-analysis of published free recall experiments demonstrates evidence for compound cuing in both conditional response probabilities and interresponse times. To help rule out a rehearsal-based account of these compound cuing 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 cuing was present in all conditions, and was not significantly influenced by the presence of interitem distractors. PMID:23957364

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Volatile Organic Compounds in Uremia

    PubMed Central

    Seifert, Luzia; Slodzinski, Rafael; Jankowski, Joachim; Zidek, Walter; Westhoff, Timm H.

    2012-01-01

    Background Although “uremic fetor” has long been felt to be diagnostic of renal failure, the compounds exhaled in uremia remain largely unknown so far. The present work investigates whether breath analysis by ion mobility spectrometry can be used for the identification of volatile organic compounds retained in uremia. Methods Breath analysis was performed in 28 adults with an eGFR ≥60 ml/min per 1.73 m2, 26 adults with chronic renal failure corresponding to an eGFR of 10–59 ml/min per 1.73 m2, and 28 adults with end-stage renal disease (ESRD) before and after a hemodialysis session. Breath analysis was performed by ion mobility spectrometryafter gas-chromatographic preseparation. Identification of the compounds of interest was performed by thermal desorption gas chromatography/mass spectrometry. Results Breath analyses revealed significant differences in the spectra of patients with and without renal failure. Thirteen compounds were chosen for further evaluation. Some compounds including hydroxyacetone, 3-hydroxy-2-butanone and ammonia accumulated with decreasing renal function and were eliminated by dialysis. The concentrations of these compounds allowed a significant differentiation between healthy, chronic renal failure with an eGFR of 10–59 ml/min, and ESRD (p<0.05 each). Other compounds including 4-heptanal, 4-heptanone, and 2-heptanone preferentially or exclusively occurred in patients undergoing hemodialysis. Conclusion Impairment of renal function induces a characteristic fingerprint of volatile compounds in the breath. The technique of ion mobility spectrometry can be used for the identification of lipophilic uremic retention molecules. PMID:23049998

  19. Sulfated compounds from marine organisms.

    PubMed

    Kornprobst, J M; Sallenave, C; Barnathan, G

    1998-01-01

    More than 500 sulfated compounds have been isolated from marine organisms so far but most of them originate from two phyla only, Spongia and Echinodermata. The sulfated compounds are presented according to the phyla they have been identified from and to their chemical structures. Biological activities, when available, are also given. Macromolecules have also been included in this review but without structural details. PMID:9530808

  20. Sensing acetylcholine and anticholinesterase compounds.

    PubMed

    Schena, Alberto; Johnsson, Kai

    2014-01-27

    Acetylcholine is a key neurotransmitter, and anticholinesterase agents are essential compounds used as medical drugs, pesticides, and chemical warfare agents. A semisynthetic fluorescence-based probe for the direct, real-time detection of acetylcholine and anticholinesterase compounds is introduced. The probe possesses good sensitivity, tunable detection range, and can be selectively targeted to cell surfaces, thereby making it an attractive tool for applications in analytical chemistry and quantitative biology. PMID:24339043

  1. 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.

  2. 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.

  3. Photochemical dimerization of organic compounds

    SciTech Connect

    Crabtree, R.H.; Brown, S.H.; Muedas, C.A.; Ferguson, R.R.

    1992-04-14

    This patent describes improvement in a Group IIb photosensitized vapor phase dimerization of an organic compound in which a gaseous mixture of a Group IIB metal and the organic compound is irradiated in a reaction zone with a photosensitizing amount of radiant energy. The improvement comprises: a continuous stream of the gaseous mixture is passed as a vapor phase in a single pass through the reaction zone at a temperature at which the thus-produced dimer condenses immediately upon the formation thereof; the starting gaseous mixture comprises hydrogen and two ethylenically unsaturated compounds selected from the group consisting of alkenes of at least six carbon atoms, unsaturated nitriles, unsaturated epoxides, unsaturated silanes, unsaturated amines, unsaturated phosphines, and fluorinated alkenes; the gaseous mixture comprises nitrous oxide and the organic compound is a saturated compound with C-H bond strengths greater than 100 kcal/mol or a mixture of the saturated compound and an alkene; or the starting gaseous comprises an activating amount of hydrogen and the dimerization is a dehydrodimerization or cross-dimerization of a saturated hydrocarbon.

  4. Miniature curved artificial compound eyes

    PubMed Central

    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

    2013-01-01

    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. PMID:23690574

  5. 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

    2013-06-01

    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. PMID:23690574

  6. 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.

  7. Host compounds for red phosphorescent OLEDs

    SciTech Connect

    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.

  8. 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

  9. 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.

  10. Microbial Identification in Pharmaceutical Compounding.

    PubMed

    Hyde, Tiffany; Anstead, James; Schade, Lisa; Zellner, James

    2016-01-01

    Compounding pharmacies and contract testing laboratories can readily utilize critical information that microbial identification methods provide. Rapidly identifying the genus and species of environmental isolates and sample contaminates provides pharmacies and laboratories the opportunity to determine the possible source and implement corrective actions to improve compounding and testing processes. The microbial identification data collected from a compounding environment is critical. It is important to have accurate and specific microbial information to guide environmental collection practices, validation studies, and troubleshooting initiatives. The different technologies available provide varying levels of identification. They range from phenotypic assays to more accurate molecular-based techniques, including macromolecular methods and whole genome sequencing. Selecting the appropriate identification methodology requires evaluating multiple factors including the level of information required (genus only, genus and species, etc.) and the pharmacy's tolerance for unidentified or incorrectly identified isolates. PMID:27125052

  11. Antimicrobial Compounds from Drypetes staudtii.

    PubMed

    Grace, David; Khan, Madiha S; Friesen, Kenneth; Ata, Athar

    2016-07-01

    Antimicrobial-directed phytochemical investigation of the MeOH extract of Drypetes staudtii afforded two new compounds, 4,5-(methylenedioxy)-o-coumaroylputrescine (1), 4,5-(methylenedioxy)-o-coumaroyl-4'-N-methylputrescine (2), along with seven known natural products 4α-hydroxyeremophila-1,9-diene-3,8-dione (3), drypemolundein B (4), friedelan-3β-ol (5), erythrodiol (6), ursolic acid (7), p-coumaric acid (8), and β-sitosterol (9). Structures of compounds 1 - 9 were elucidated with the aid of extensive NMR and mass spectral studies. All of the isolates exhibited antibacterial activity against Gram-positive and Gram-negative bacteria with minimum inhibitory concentration (MIC) in the range of 8 - 128 μg/ml. Compounds 1 - 2 were also moderately active against Candida albicans with an MIC value of 32 μg/ml. PMID:27288642

  12. 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

  13. 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

  14. 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

  15. Biodegradation of halogenated organic compounds.

    PubMed

    Chaudhry, G R; Chapalamadugu, S

    1991-03-01

    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

  16. Persulfate Oxidation of Gasoline Compounds

    NASA Astrophysics Data System (ADS)

    Sra, K.; Thomson, N.; Barker, J.

    2009-05-01

    In situ chemical oxidation (ISCO) using persulfate is a promising remediation technology that can be potentially applied to a wide range of organic contaminants. Gasoline compounds are of particular interest because they extensively impact the soil and groundwater, and are highly persistent and toxic. In this investigation, destruction of specific gasoline compounds (benzene, toluene, ethylbenzenes, xylenes, trimethylbenzenes (TMBs) and naphthalene), and fractions (F1 and F2) by activated and inactivated persulfate was studied at the bench-scale. Aqueous phase batch reactors (25 mL) for inactivated systems employed persulfate at two concentrations (1 or 20 g/L), and activated systems were conducted with a persulfate concentration of 20 g/L. In the activated systems, the ability of hydrogen peroxide or chelated-ferrous as an activator was examined at two experimental conditions (peroxide molar ratio 0.1 and 1.0 with respect to persulfate; and citric acid chelated ferrous at 150 and 600 mg/L). All treatments and controls contained an initial gasoline concentration of approximately 25 mg/L and were run in triplicate. Sampling for gasoline compounds was conducted over <28 day reaction period. The controls showed insignificant degradation for all the gasoline compounds and fractions examined while inactivated persulfate at 1 g/L showed little (<10%) decrease in the concentration of gasoline compounds over the 28 day reaction period. Inactivated persulfate at 20 g/L demonstrated a significant decrease in the aqueous concentration of BTEX (>99%), TMB (>94%) and naphthalene (>71%). Oxidation of the F1 fraction (>94%) was more pronounced than the F2 fraction (>80%), and >93% TPH was oxidized. Use of peroxide as an activator at a molar ratio of 0.1 improved the destruction of TMBs (>99%) and naphthalene (>85%) while maintaining the high removal of BTEX (>99%) compounds. Increase in activator strength (molar ratio 1.0) decreased the destruction of xylenes (>86%) and TMBs (>81

  17. Instability of viscoelastic compound jets

    NASA Astrophysics Data System (ADS)

    Ye, Han-Yu; Yang, Li-Jun; Fu, Qing-Fei

    2016-04-01

    This paper investigates the axisymmetric instability of a viscoelastic compound jet, for which the constitutive relation is described by the Oldroyd B model. It is found that a viscoelastic compound jet is more unstable than a Newtonian compound jet, regardless of whether the viscoelastic compound jet is inner-Newtonian-outer-viscoelastic, inner-viscoelastic-outer-Newtonian, or fully viscoelastic. It is also found that an increase in the stress relaxation time of the inner or outer fluid renders the jet more unstable, while an increase in the time constant ratio makes the jet less unstable. An analysis of the energy budget of the destabilization process is performed, in which a formulation using the relative rate of change of energy is adopted. The formulation is observed to provide a quantitative analysis of the contribution of each physical factor (e.g., release of surface energy and viscous dissipation) to the temporal growth rate. The energy analysis reveals the mechanisms of various trends in the temporal growth rate, including not only how the growth rate changes with the parameters, but also how the growth rate changes with the wavenumber. The phenomenon of the dispersion relation presenting two local maxima, which occurred in previous research, is explained by the present energy analysis.

  18. 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. PMID:27276233

  19. Absorption of different lead compounds

    PubMed Central

    Barltrop, D.; Meek, F.

    1975-01-01

    A rapid method for the determination of relative absorption of dietary lead by rats is described. The influence of age, weight and dose rate has been determined and using standard conditions the tissue lead content of blood, kidney and femur are significantly correlated with each other and are a function of ingested lead. Eight lead compounds were evaluated using this technique and the findings related to lead acetate as a reference compound. Of the inorganic preparations studied, lead carbonate (basic) and metallic lead showed a twelve-fold difference in absorption, with the remaining compounds giving intermediate values. The absorption of lead from four organic compounds was determined from diets containing 7·5% corn oil added to the standard diet. Lead tallate was absorbed to the same degree as lead acetate, but lesser absorptions resulted from lead octoate, naphthenate and alsynate. The addition of corn oil to a final concentration of 7·5% of the diet enhanced the absorption of lead acetate. PMID:1208290

  20. Cerium Oxide and Cerium Compounds

    Integrated Risk Information System (IRIS)

    Cerium oxide and cerium compounds ; CASRN 1306 - 38 - 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 fo

  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. 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…

  3. 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…

  4. Reconstructive compounding for IVUS palpography.

    PubMed

    Danilouchkine, Mikhail G; Mastik, Frits; van der Steen, Antonius F W

    2009-12-01

    This study proposes a novel algorithm for luminal strain reconstruction from sparse irregularly sampled strain measurements. It is based on the normalized convolution (NC) algorithm. The novel extension comprises the multilevel scheme, which takes into account the variable sampling density of the available strain measurements during the cardiac cycle. The proposed algorithm was applied to restore luminal strain values in intravascular ultrasound (IVUS) palpography. The procedure of reconstructing and averaging the strain values acquired during one cardiac cycle forms a technique, coined as reconstructive compounding. The accuracy of strain reconstruction was initially tested on the luminal strain map, computed from 3 in vivo IVUS pullbacks. The high quality of strain restoration was observed after systematically removing up to 90% of the initial elastographic measurements. The restored distributions accurately reproduced the original strain patterns and the error did not exceed 5%. The experimental validation of the reconstructed compounding technique was performed on 8 in vivo IVUS pullbacks. It demonstrated that the relative decrease in number of invalid strain estimates amounts to 92.05 +/- 6.03% and 99.17 +/- 0.92% for the traditional and reconstructive strain compounding schemes, respectively. In conclusion, implementation of the reconstructive compounding scheme boosts the diagnostic value of IVUS palpography. PMID:20040400

  5. Clickable Lipids: Azido and Alkynyl Fatty Acids and Triacylglycerols

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Abstract: Hydroxy fatty acids (FA), which were isolated from glycolipids that can be prepared fermentatively from fats and oils, have been synthetically modified to contain azide and alkyne functional groups. These particular functional groups were chosen because they can participate in a copper-ca...

  6. Olive oil phenolic compounds affect the release of aroma compounds.

    PubMed

    Genovese, Alessandro; Caporaso, Nicola; Villani, Veronica; Paduano, Antonello; Sacchi, Raffaele

    2015-08-15

    Twelve aroma compounds were monitored and quantified by dynamic headspace analysis after their addition in refined olive oil model systems with extra virgin olive oil (EVOO) biophenols to simulate EVOO aroma. The influence of polyphenols on aroma release was studied under simulated mouth conditions by using human saliva, and SPME-GC/MS analysis. While few differences were observed in orthonasal assay (without saliva), interesting results were obtained for retronasal aroma. Biophenols caused generally the lowest headspace release of almost all volatile compounds. However, only ethyl esters and linalool concentrations were significantly lower in retronasal than orthonasal assay. Saliva also caused higher concentration of hexanal, probably due to hydroperoxide lyase (HPL) action on linoleyl hydroperoxides. Epicatechin was compared to EVOO phenolics and the behaviour was dramatically different, likely to be due to salivary protein-tannin binding interactions, which influenced aroma headspace release. These results were also confirmed using two extra virgin olive oils. PMID:25794752

  7. Heuristics for chemical compound matching.

    PubMed

    Hattori, Masahiro; Okuno, Yasushi; Goto, Susumu; Kanehisa, Minoru

    2003-01-01

    We have developed an efficient algorithm for comparing two chemical compounds, where the chemical structure is treated as a 2D graph consisting of atoms as vertices and covalent bonds as edges. Based on the concept of functional groups in chemistry, 68 atom types (vertex types) are defined for carbon, nitrogen, oxygen, and other atomic species with different environments, which has enabled detection of biochemically meaningful features. Maximal common subgraphs of two graphs can be found by searching for maximal cliques in the association graph, and we have introduced heuristics to accelerate the clique finding. Our heuristic procedure is controlled by some adjustable parameters. Here we applied our procedure to the latest KEGG/LIGAND database with different sets of parameters, and demonstrated the correlation of parameters in our algorithm with the distribution of similarity scores and/or the execution time. Finally, we showed the effectiveness of our heuristics for compound pairs along metabolic pathways. PMID:15706529

  8. 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.

  9. 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.

  10. 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.