Sample records for diisopropyl fluorophosphatase dfpase

  1. Preliminary time-of-flight neutron diffraction study on diisopropyl fluorophosphatase (DFPase) from Loligo vulgaris

    Blum, Marc-Michael [Institute of Biophysical Chemistry, J. W. Goethe University Frankfurt, Max-von-Laue-Strasse 9, D-60438 Frankfurt (Germany); Bundeswehr Institute of Pharmacology and Toxicology, Neuherbergstrasse 11, D-80937 Munich (Germany); Koglin, Alexander [Institute of Biophysical Chemistry, J. W. Goethe University Frankfurt, Max-von-Laue-Strasse 9, D-60438 Frankfurt (Germany); Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115 (United States); Rüterjans, Heinz [Institute of Biophysical Chemistry, J. W. Goethe University Frankfurt, Max-von-Laue-Strasse 9, D-60438 Frankfurt (Germany); Schoenborn, Benno [Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Langan, Paul [Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Department of Chemistry, University of Toledo, Toledo, OH 53606 (United States); Chen, Julian C.-H., E-mail: [Institute of Biophysical Chemistry, J. W. Goethe University Frankfurt, Max-von-Laue-Strasse 9, D-60438 Frankfurt (Germany)


    Diisopropyl fluorophosphatase (DFPase) effectively hydrolyzes a number of organophosphorus nerve agents, including sarin, cyclohexylsarin, soman and tabun. Neutron diffraction data have been collected from DFPase crystals to 2.2 Å resolution in an effort to gain further insight into the mechanism of this enzyme. The enzyme diisopropyl fluorophosphatase (DFPase) from Loligo vulgaris is capable of decontaminating a wide variety of toxic organophosphorus nerve agents. DFPase is structurally related to a number of enzymes, such as the medically important paraoxonase (PON). In order to investigate the reaction mechanism of this phosphotriesterase and to elucidate the protonation state of the active-site residues, large-sized crystals of DFPase have been prepared for neutron diffraction studies. Available H atoms have been exchanged through vapour diffusion against D{sub 2}O-containing mother liquor in the capillary. A neutron data set has been collected to 2.2 Å resolution on a relatively small (0.43 mm{sup 3}) crystal at the spallation source in Los Alamos. The sample size and asymmetric unit requirements for the feasibility of neutron diffraction studies are summarized.

  2. Hydrolysis of DFP and the Nerve Agent (S)-Sarin by DFPase Proceeds Along Two Different Reaction Pathways: Implica-tions for Engineering Bioscavengers

    Wymore, Troy W [ORNL; Langan, Paul [ORNL; Smith, Jeremy C [ORNL; Field, Martin J. [Institut de Biologie Structurale Jean-Pierre Ebel; Parks, Jerry M [ORNL


    Organophosphorus (OP) nerve agents such as (S)-sarin are among the most highly toxic compounds that have been synthesized. Engineering enzymes that catalyze the hydrolysis of nerve agents ( bioscavengers ) is an emerging prophylactic approach to diminishing their toxic effects. Although its native function is not known, diisopropyl fluorophosphatase (DFPase) from Loligo vulgaris catalyzes the hydrolysis of OP compounds. Here, we investigate the mechanisms of diisopropylfluorophosphate (DFP) and (S)-sarin hydrolysis by DFPase with quantum mechanical/molecular mechanical (QM/MM) umbrella sampling simulations. We find that the mechanism for hydrolysis of DFP involves nucleophilic attack by Asp229 on phosphorus to form a pentavalent intermediate. P F bond dissociation then yields a phosphoacyl enzyme intermediate in the rate-limiting step. The simulations suggest that a water molecule, coordinated to the catalytic Ca2+, donates a proton to Asp121 and then attacks the tetrahedral phosphoacyl intermediate to liberate the diisopropylphosphate product. In contrast, the calculated free energy barrier for hydrolysis of (S)-sarin by the same mechanism is highly unfavorable, primarily due to the instability of the pentavalent phosphoenzyme species. Instead, simulations suggest that hydrolysis of (S)-sarin proceeds by a mechanism in which Asp229 could activate an intervening water molecule for nucleophilic attack on the substrate. These findings may lead to improved strategies for engineering DFPase and related six-bladed -propeller folds for more efficient degradation of OP compounds.

  3. A Green Synthesis of Diisopropyl Phosphoryl Amino Acid


    In this paper, we report that diisopropyl phosphoryl amino acid could be prepared with reasonable yields under solvent-free condition by adding amino acid to the mixture of diisopropyl phosphite and N-chlorodiisopropylamine.

  4. Efficient Surface Display of Diisopropylfluorophosphatase (DFPase) in E. coli for Biodegradation of Toxic Organophosphorus Compounds (DFP and Cp).

    Latifi, Ali Mohammad; Karami, Ali; Khodi, Samaneh


    Compounds including organophosphorus pesticides (OPs) and chemical nerve agents are toxic compounds synthesized recently which disrupt the mechanisms of neural transmission. Therefore, a critical requirement is the development of a bio-refining technology to facilitate the biodegradation of organophosphorus pollutants. The diisopropylfluorophosphatase (DFPase, EC from the ganglion and brain of Loligo vulgaris acts on P-F bonds present in some OPs. Intracellular production of OPs-degrading enzymes or the use of native bacteria and fungi leads to a low degradation rate of OPs due to a mass transfer issue which reduces the overall catalytic efficiency. To overcome this challenge, we expressed DFPase on the surface of E. coli for the first time by employing the N-terminal domain of the ice nucleation protein (InaV-N) as an anchoring motif. Tracking the recombinant protein confirmed that DFPase is successfully located on the outer membrane. Further studies on its activity to degrade diisopropylfluorophosphate (DFP) showed its significant ability for the biodegradation of diisopropylfluorophosphate (DFP) with a specific activity of 500 U/mg of wet cell weight. Recombinant cells could also degrade chlorpyrifos (Cp) with an activity equivalent to a maximum value of 381.44 U/ml with a specific activity of 476.75 U/mg of cell, analyzed using HPLC technique. The optimum activity of purified DFPase was found at 30 °C. A more increased activity was also obtained in the presence of glucose-mineral-salt (GMS) supplemented with tryptone and 100 mg/L Co(2+) ion. These results highlight the high potential of the InaV-N anchoring domain to produce an engineered bacterium that can be used in the bioremediation of pesticide-contaminated environments.

  5. N-(Diphenyl-vinyl-idene)-2,6-diisopropyl-aniline.

    Imhof, Wolfgang


    The title compound, C(26)H(27)N, was prepared by the elimination of water from N-(2,6-diisopropyl-phen-yl)-2,2-diphenyl-acetamide. The angle at the central C atom of the cumulene measures 172.5 (4)°. Mol-ecules are connected into infinite chains by inter-molecular C-H⋯N inter-actions.

  6. Purification of neuropathy target esterase from avian brain after prelabelling with [3H]diisopropyl phosphorofluoridate.

    Rüffer-Turner, M E; Read, D J; Johnson, M K


    Neuropathy target esterase from hen brains was radiolabelled at the active site with [3H]diisopropyl phosphorofluoridate. The labelled protein was purified by differential centrifugation and Nonidet P40 solubilization, detergent phase partitioning, anion exchange, and preparative sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The volatilizable counts assay and analytical SDS-PAGE were used to monitor the protein. The 150-kDa subunit polypeptide appears as a single band on analytical SDS-PAGE.

  7. ESI/MS of N-(O, O-Diisopropyl) Phosphoryl Aromatic Amino Acids and their Stability Investigation Using HPLC/UV/ESI/MS

    Hong Xia LIU; Shu Sheng ZHANG; Jian Chen ZHANG; Xiao YANG; Ling Bo QU; Yu Fen ZHAO


    The full scan ESI/MS and ESI/MS2 of N-(O, O-diisopropyl) phosphoryl aromatic amino acids (DIPPAAAs), N-(O, O-diisopropyl) phosphoryl phenylalanine, N-(O, O-diisopropyl)phosphoryl tryptophan and N-(O, O-diisopropyl) phosphoryl tyrosine, were obtained. The specific ions for them were found. Their stability in the LC mobile phase was investigated using developed HPLC/UV/ESI/MS and the results demonstrated that the DIPPAAAs were stable in the mobile phase (5 mmol/L NH4Ac-MeCN (80:20,v/v, pH7.5) within 48 h.

  8. Cooperative study with sup(99m)Tc diisopropyl-IDA on biliary tract diseases

    Mitta, A.E.A.; Mollerach, F; Almeida, C.A. (Complejo Medico Policial Churruca Visca, Buenos Aires (Argentina). Servicio de Medicina Nuclear)


    The results of a cooperative study on the investigation of the biliary tract with sup(99m)Tc diisopropyl-IDA are presented. 15 normal volunteers and 75 patients with acute cholecystitis (AC), chronic cholecystitis (CC), hepatocellular jaundice (HCJ), incomplete extrahepatic biliary obstruction (IEBO) and complete extrahepatic biliary obstruction (CEBO) were studied. The biological behaviour of the radiopharmaceutical in the two groups was determined through the measurement of the uptake times and of the times of arrival in the hepatic parenchyma, in the intra and extrahepatic bile ducts, in the gallbladder, in the duodenum and in the kidneys. The pathophysiologic features found in the AC, CC, HCJ, IEBO and CEBO are described. It is concluded that the procedure has a selective indication in the AC, that its value is limited in the CC, and that in jaundice, except in very special situations, the method gives very little information of clinical value. The possibility of performing cooperative scientific studies between Latin-American Departments, increasing their efficiency, is emphasized.

  9. High temperature shock tube experiments and kinetic modeling study of diisopropyl ketone ignition and pyrolysis

    Barari, Ghazal


    Diisopropyl ketone (DIPK) is a promising biofuel candidate, which is produced using endophytic fungal conversion. In this work, a high temperature detailed combustion kinetic model for DIPK was developed using the reaction class approach. DIPK ignition and pyrolysis experiments were performed using the UCF shock tube. The shock tube oxidation experiments were conducted between 1093K and 1630K for different reactant compositions, equivalence ratios (φ=0.5–2.0), and pressures (1–6atm). In addition, methane concentration time-histories were measured during 2% DIPK pyrolysis in argon using cw laser absorption near 3400nm at temperatures between 1300 and 1400K near 1atm. To the best of our knowledge, current ignition delay times (above 1050K) and methane time histories are the first such experiments performed in DIPK at high temperatures. Present data were used as validation targets for the new kinetic model and simulation results showed fair agreement compared to the experiments. The reaction rates corresponding to the main consumption pathways of DIPK were found to have high sensitivity in controlling the reactivity, so these were adjusted to attain better agreement between the simulation and experimental data. A correlation was developed based on the experimental data to predict the ignition delay times using the temperature, pressure, fuel concentration and oxygen concentration.

  10. Toxicity and characterization of cholinesterase-inhibition induced by diisopropyl fluorophosphate in Artemia salina larvae.

    Sánchez-Fortún, S; Barahona, M V


    The acute toxicity of diisopropyl fluorophosphate (DFP) on three age classes of Artemia salina was evaluated. An increase in toxicity of this organophosphorous (OP) compound was found following longer development of A. salina larvae. The effects of pretreatment with the non-selective muscarinic antagonist atropine, the two reversible acetylcholinesterase inhibitors physostigmine and pyridostigmine, and the cholinesterase-reactivating oxime 2-pyridine aldoxime methoiodide (2-PAM), as individual and combined pretreatments, on DFP-induced lethality in 24h Artemia were also investigated. The lethal action of DFP was not prevented by pretreatment of 24h Artemia with atropine, physostigmine, and pyridostigmine, while 2-PAM proved effective against intoxication with this OP compound. The inhibitory effects of combinations of atropine (10(-5)M) plus 2-PAM or physostigmine were greater than those elicited by either drug alone, with the maximum protection afforded being 100%. Pretreatment with 2-PAM (10(-6)M) plus physostigmine or pyridostigmine was ineffective. These results suggest that the combinations of atropine plus 2-PAM or physostigmine are effective in the prevention of the lethal effects induced by DFP in A. salina larvae.

  11. Phase equilibrium properties of binary and ternary systems containing di-isopropyl ether + 1-butanol + benzene at 313.15 K

    Villamanan, Rosa M. [Grupo de Termodinamica y Calibracion TERMOCAL, Dpto. Ingenieria Energetica y Fluidomecanica, E.T.S. de Ingenieros Industriales, Universidad de Valladolid, Paseo del Cauce s/n, E-47071 Valladolid (Spain)]. E-mail:; Martin, M. Carmen [Grupo de Termodinamica y Calibracion TERMOCAL, Dpto. Ingenieria Energetica y Fluidomecanica, E.T.S. de Ingenieros Industriales, Universidad de Valladolid, Paseo del Cauce s/n, E-47071 Valladolid (Spain)]. E-mail:; Chamorro, Cesar R. [Grupo de Termodinamica y Calibracion TERMOCAL, Dpto. Ingenieria Energetica y Fluidomecanica, E.T.S. de Ingenieros Industriales, Universidad de Valladolid, Paseo del Cauce s/n, E-47071 Valladolid (Spain)]. E-mail:; Villamanan, Miguel A. [Grupo de Termodinamica y Calibracion TERMOCAL, Dpto. Ingenieria Energetica y Fluidomecanica, E.T.S. de Ingenieros Industriales, Universidad de Valladolid, Paseo del Cauce s/n, E-47071 Valladolid (Spain)]. E-mail:; Segovia, Jose J. [Grupo de Termodinamica y Calibracion TERMOCAL, Dpto. Ingenieria Energetica y Fluidomecanica, E.T.S. de Ingenieros Industriales, Universidad de Valladolid, Paseo del Cauce s/n, E-47071 Valladolid (Spain)]. E-mail:


    (Vapour + liquid) equilibria data of (di-isopropyl ether + 1-butanol + benzene) (di-isopropyl ether + 1-butanol) and (1-butanol + benzene) have been measured at T = 313.15 K using an isothermal total pressure cell. Data reduction by Barker's method provides correlations for the excess molar Gibbs energy using the Margules equation for the binary systems and the Wohl expansion for the ternary. The Wilson, NRTL and UNIQUAC models have been applied successfully to both the binary and the ternary systems reported here.

  12. Crystal Structure of Bis (O,O’-diisopropyl dithiophosphate):[(C3H7O)2PS2]2

    ZHANG Shu-sheng; LI Xue-mei; WANG Jin-li; WAN Jun; JIAO Kui


    The crystal and molecular structures of [(C3H7O)2PS2]2 (CCDC No. 217201) were determined by means of X-ray crystallography. It crystallized in a triclinic system with space group P(-1) and lattice parameters a=0.82794(3) nm, b=0.84764(2) nm, c=0.85034(3) nm, α=97.78(3)°, β=110.77(3)°, γ= 94. 95 (3)°,V= 0. 54701(9) nm3, Z= 1. In this molecule, the two diisopropyl dithiophosphate groups, [(C3H7O)2PS2]2,which are parallel to each other, are linked by an S-S bond and there exist inversion centers in the molecule.In the structure, the P = S bonds in the two dithiophosphate units are trans-oriented to each other.

  13. Synthesis of 3,5-diisopropyl(carboxy- sup 14 C)salicylic acid and its sup 67 Cu complex

    Chidambaram, M.V.; Epperson, C.E.; Williams, S.; Gray, R.A.; Sorenson, J.R.J. (Univ. of Arkansas for Medical Sciences, Little Rock (USA). College of Pharmacy)


    The synthesis of 3,5-diisopropyl(carboxy-{sup 14}C)salicylic acid was achieved via Kolbe-Schmitt carboxylation of potassium 2,4-di-isopropylphenolate. The yield of this acid was 81% based upon the weight of the product and 93% based upon radioactivity incorporated into the labeled acid which contains 98% {sup 14}C in the carboxyl group (specific activity = 5.1 {mu}Ci/mg). The labeled acid was characterized by ultraviolet spectrophotometry and purity established by thin-layer chromatography, autoradiography, and liquid scintillation counting. A 90% yield of the double labeled {sup 14}C, {sup 67}Cu-complex (specific activity = 4.6 {mu}Ci {sup 67}Cu/mg) was obtained using conditions developed with non-radioactive reactants. The presence of {sup 67}Cu in this complex was established using {gamma}-ray emission spectrophometry. (author).

  14. Preparation and photoelectronic and electrochemical properties of oligo [(1,1-diisopropyl-3,4-diphenyl-2,5-silolene)-co-(alkylphenylsilylene)]s

    Jung, Young Min; Park, Young Tae [Dept. of Chemistry, Keimyung University, Daegu (Korea, Republic of); Baek, Seong Ho [Div. of Green Energy Research, Daegu Gyeongbuk Institute of Science and Technology, Daegu (Korea, Republic of)


    We oligomerized 2,5-dibromo-1,1-diisopropyl-3,4-diphenyl-2,5-silole with dichloroalkylphenylsilanes utilizing n-BuLi to yield conjugated oligo [(1,1-diisopropyl-3,4-diphenyl-2,5-silolene)-co-(alkylphenylsilylene)]s. Gel permeation chromatography measurements confirm that the synthesized materials are oligomeric. In addition, the prepared oligomers show characteristic diene stretching bands at 1579–1599 cm{sup −1} in their FT-IR spectra. Furthermore, the oligomers are highly soluble in common organic solvents such as tetrahydrofuran and chloroform. In tetrahydrofuran, the oligomers show strong maximum electronic absorption bands at 253–292 nm with molar absorptivities of 1.61 × 10{sup 2} to 2.57 × 10{sup 4} /cm M in their UV–vis electronic absorption spectra, indicating that the maxima are red-shifted by 5–8 nm compared to the 2,5-dibromo-1,1-diisopropyl-3,4-diphenyl-2,5-silole monomer, strong maximum electronic excitation bands at 292–312 nm, and strong maxima electronic emission bands at 385–396 nm in the emission fluorescence spectra. The emission and absorption spectra strongly suggest that the prepared silole-containing oligomers may be conjugated through the oligomer backbone. In particular, cyclic voltammetry measurements of oligo[(1,1-diisopropyl-3,4-diphenyl-2,5-silolene)-co-(diphenylsilylene)] deposited on a glassy carbon electrode in 1.0 M aqueous hydrogen chloride show two oxidation potentials at 0.98 and 1.61 V vs. Ag/Ag{sup +}, and two reduction potentials at 0.00 and −1.93 V vs. Ag/Ag{sup +}. The oligomers were stable on heating to 200 °C under nitrogen, as determined by thermogravimetric analysis, losing between 4% and 23% of their starting weights.

  15. Diacetonitrile[N,N′-bis(2,6-diisopropyl­phenyl)ethane-1,2-diimine]dichloridochromium(II) acetonitrile solvate

    Peitz, Stephan; Peulecke, Normen; Müller, Bernd H.; Spannenberg, Anke; Rosenthal, Uwe


    The title compound, [CrCl2(CH3CN)2(C26H36N2)]·CH3CN, was synthesized by the reaction of CrCl2(THF)2 with N,N′-bis­(2,6-diisopropyl­phen­yl)ethane-1,2-diimine in dichloro­methane/acetonitrile. The chromium center is coordinated by two N atoms of the chelating diimine ligand, two chloride ions in a trans configuration with respect to each other, and by two N atoms of two acetonitrile mol­ecules in a distorted octa­hedral geometry. PMID:21578093

  16. A probe on the intermolecular forces in diisopropyl ether-n-butyric acid mixture by dielectric, FTIR studies and quantum chemical calculations.

    Arivazhagan, G; Shanmugam, R; Elangovan, A


    The results of FTIR spectral measurement on equimolar diisopropyl ether-butyric acid binary mixture and quantum chemical calculations on the complex molecule have been presented. Dielectric studies have been carried out on the binary mixture over the entire composition range and at four different temperatures 303 K, 308 K, 313 K and 318 K. n-Butyric acid seems to prefer less polar ether to interact with it. It appears that the usual interpretation of variation of static dielectric constant and positive deviation of excess permittivity from ideal mixture behavior needs to be relooked.

  17. Synthesis of 2,4-diisopropyl-5,5-dimethyl- 1,3-dioxane catalyzed by Brφnsted acidic ionic liquids

    WANG WenJuan; WANG YouFei; CHENG WenPing; WANG Jian; YANG JianGuo; HE MingYuan


    The acetalization reactions of isobutyraldehyde with 2,2,4-trimethyl-1,3-pentanediol (TMPD) for the synthesis of 2,4-diisopropyl-5,5-dimethyl-1,3-dioxane were carried out under mild reaction conditions using four water-stable Brφnsted-acidic task-specific ionic liquids ([HMIM]BF4, -SO3H functionalized acidic ionic liquid, -COOH functionalized acidic ionic liquid, [NMP][HSO4]) as environmentally benign catalysts for the first time. The process is highly effective and very selective. The -COOH functional-ized Bronsted acidic ionic liquid with the two acid sites (IL-3) exhibited the most excellent catalytic performance under mild reaction conditions. The --COOH functionalized Brφnsted acidic ionic liquid could be conveniently separated from the product and easily recycled in subsequent runs.

  18. Palladium(II complexes with R2edda derived ligands: Part VI. O,O’-diisopropyl-(S,S-ethylenediamine-N,N’-di-2-(4-methylpentanoate dihydrochloride dihydrate and its palladium(II complex: Synthesis and characterization

    Zmejkovski Bojana B.


    Full Text Available A new R2edda-type ester, O,O’-diisopropyl-(S,S-ethylenediamine-N,N’-di-2-(4-methyl-pentanoate dihydrochloride dihydrate, [(S,S-H2iPr2eddl]Cl2∙2H2O, 1, and its palladium(II complex, dichlorido(O,O’-diisopropyl-(S,S-ethylenediamine-N,N’-di-2-(4-methylpentanoatepalla-dium(II hemihydrate, [PdCl2{(S,S-iPr2eddl}]∙0.5H2O, 2, were synthesized and characterized by elemental analysis, IR and NMR spectroscopy. As expected the palladium(II complex is found in two from three diastereoisomeric forms (R,R, (S,S and (R,S≡(S,R. [Projekat Ministarstva nauke Republike Srbije, br. 172035

  19. UV and γ-ray resistance of poly(N-methylmaleimide-alt-isobutene) and poly(diisopropyl fumarate) as transparent polymer films

    Imaizumi, Ryota; Furuta, Masakazu; Okamura, Haruyuki; Matsumoto, Akikazu


    UV and γ-ray resistance of transparent polymers obtained by radical polymerization of maleic and fumaric acid derivatives, i.e., an alternating copolymer of N-methylmaleimide and isobutene (PMI) and poly(diisopropyl fumarate) (PDiPF), was investigated. Transmittance in UV and visible regions of these polymers were examined after UV irradiation and compared with the results for poly(methyl methacrylate) (PMMA) and polycarbonate (PC) as conventional transparent polymers. The order of stability toward UV irradiation was PMMA≈PDiPF>PMI>>PC, deduced from changes in the transmittance of 380 nm light. Tensile mechanical properties, such as elastic modulus, maximum strength, and elongation values of PMI, PDiPF, and PMMA were also investigated after UV and γ-radiation. UV irradiation induced the side chain scission of PMI and PDiPF via Norrish I type reaction as well as crosslinking by combination between formed polymer radicals, leading to deterioration in their optical and mechanical properties. γ-radiation induced significant changes in molecular weight and mechanical properties of the polymers. In conclusion, PMI exhibited unchanged mechanical properties and PDiPF maintained its high transparency under various irradiation conditions.

  20. Atomic layer deposition of stoichiometric Co{sub 3}O{sub 4} films using bis(1,4-di-iso-propyl-1,4-diazabutadiene) cobalt

    Han, Byeol; Park, Jae-Min; Choi, Kyu Ha; Lim, Wan-Kyu; Mayangsari, Tirta R. [Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 143-747 (Korea, Republic of); Koh, Wonyong [R& D Center, UP Chemical Co., Ltd. Pyeongtaek-si, Gyeonggi-do 459-050 (Korea, Republic of); Lee, Won-Jun, E-mail: [Department of Nanotechnology and Advanced Materials Engineering, Sejong University, Seoul 143-747 (Korea, Republic of)


    We report the deposition of cobalt oxide films at 120–300 °C using alternating injections of a novel liquid cobalt precursor, bis(1,4-di-iso-propyl-1,4-diazabutadiene)cobalt [C{sub 16}H{sub 32}N{sub 4}Co, Co(dpdab){sub 2}], and ozone. The saturation doses of Co(dpdab){sub 2} and O{sub 3}/O{sub 2} were 4 × 10{sup 6} and 1 × 10{sup 8} L, respectively. The atomic layer deposition (ALD) temperature window was between 120 °C and 250 °C with a maximum growth per cycle of 0.12 nm/cycle. The deposited films showed excellent step coverage. Cobalt oxide films deposited at 250 °C consisted of stoichiometric and crystalline Co{sub 3}O{sub 4}. - Highlights: • Cobalt oxide films were grown by ALD using a novel cobalt precursor and O{sub 3}. • The ALD temperature window was 120–250 °C with a growth per cycle of 0.12 nm/cycle. • Cobalt oxide thin films showed excellent step coverage. • Cobalt oxide films deposited at 250 °C were stoichiometric and crystalline Co{sub 3}O{sub 4}.

  1. Lewis酸性离子液体催化合成丁二酸二异丙酯%Synthesis of succinic acid diisopropyl ester catalyzed by Lewis acid ionic liquids

    赵地顺; 葛京京; 翟建华; 张娟; 刘猛帅; 李俊盼


    采用两步法制备了9种不同的Lewis酸性离子液体,采用1H NMR、FT-IR对离子液体的结构进行了表征,并系统地考察了其对丁二酸和异丙醇酯化反应的催化性能。结果表明,离子液体随着卤化物用量增加表现出更强的酸性。其中[Bmim]Br-Fe2Cl6催化合成丁二酸二异丙酯效果良好,催化剂用量为丁二酸质量的10.0%,反应温度100℃,反应时间4 h,酸醇摩尔比为1:5,丁二酸二异丙酯收率为88.9%,酯化率达92.7%。离子液体重复使用6次后,产品收率下降1.7%。%Nine kinds of different Lewis acid ionic liquids were synthesized by two-step process and their structures were characterized with 1H NMR and FT-IR. Lewis acid ionic liquids prepared were used to catalyze the esterification reaction of succinic acid and isopropyl alcohol. With the increase of dosage of halide, the ionic liquids showed stronger acidity. [Bmim]Br-Fe2Cl6 had the best catalytic performance, and optimal conditions for the synthesis of succinic acid diisopropyl ester were obtained as follows, amount of catalyst 10.0%(g/g)of succinic acid, reaction temperature 100℃ and reaction time 4 h, succinic acid and isopropyl alcohol ratio 1:5. Under the optimal conditions, the yield of succinic acid diisopropyl ester was up to 88.9%, esterification rate was 92.7%.The catalyst was recycled 6 times, and the yield of succinic acid diisopropyl ester only decreased by 1.7%.

  2. [N,N'-Bis(2,6-diisopropyl-phen-yl)methanimidamidato][η-1,4-bis-(tri-methyl-sil-yl)cyclo-octa-tetra-enyl](tetra-hydro-furan)-samarium(III) toluene monosolvate.

    Edelmann, Anja; Hrib, Cristian G; Hilfert, Liane; Blaurock, Steffen; Edelmann, Frank T


    The title compound, [Sm(C(25)H(35)N(2))(C(14)H(24)Si(2))(C(4)H(8)O)]·C(7)H(8), was prepared by treatment of anhydrous samarium trichloride with a 1:1 mixture of in situ-prepared Li(DippForm) [DippFormH = N,N'-bis-(2,6-diisopropyl-phen-yl)methanimidamide] and Li(2)(COT'') [COT'' = 1,4-bis-(trimethyl-sil-yl)cyclo-octa-tetra-enyl] in tetra-hydro-furan (THF). Despite the presence of two very bulky ligands (COT'' and DippForm), the mol-ecule still contains one coordinated THF ligand. The overall coordination geometry around the Sm(III) atom resembles a three-legged piano-stool with the COT'' ligand being η(8)-coordinated and the DippForm(-) anion acting as an N,N'-chelating ligand [Sm-N = 2.5555 (15) and 2.4699 (15) Å]. The asymmetric unit also contains a disordered mol-ecule of toluene, the refined ratio of the two components being 0.80 (4):0.20 (4).

  3. Active-site peptides of acetylcholinesterase of Electrophorus electricus: labelling of His-440 by 1-bromo-[2-14C]pinacolone and Ser-200 by tritiated diisopropyl fluorophosphate.

    Salih, E; Chishti, S B; Vicedomine, P; Cohen, S G; Chiara, D C; Cohen, J B


    To characterize the structure of the active site of acetylcholinesterase (AChE) from the electric organ of E. electricus, we identified sites of incorporation of two active-site affinity labels, [3H]diisopropyl fluorophosphate ([3H]DFP), and 1-bromo-2-[14C]pinacolone ([14C]BrPin). AChE was isolated, purified, inactivated and digested with trypsin, and peptides containing 3H or 14C were purified by reverse-phase HPLC and characterized by N-terminal sequence analysis. [3H]DFP, labelling Ser-200, was found in a single peptide, QVTIFGESAGAASVGMHLLSPDSR, 83% identical with the sequence from Thr-193 to Arg-216 deduced for AChE of T. californica, with Gln, Ala, Leu, and Asp in place of Thr-193, Gly-203, Ile-210 and Gly-214, respectively, and 87% identical with that from bovine and human brain AChEs. Inactivation by [14C]BrPin led to two radioactive peptides. One, ASNLVWPEWMGVIHGYEIEFVFGLPLEK, was 96% identical with that extending from Ala-427 to Lys-454 of T. californica. Release of 14C in cycle 14 established reaction of [14C]BrPin with active-site His-440, protected by 5-trimethylammonio-2-pentanone (TAP). The other peptide, LLXVTENIDDAER, 77% homologous with that of T. californica extending from Leu-531 to Arg-543, had label associated with the third cycle, not protected by TAP, corresponding to Asn-533. The slow inactivation of eel AChE by reaction of [14C]BrPin at His-440 contrasts with that of AChE from T. nobiliana, where it reacts rapidly with a free cysteine, Cys-231, not present in eel AChE. For both AChEs, inactivation by BrPin prevents subsequent reaction with [3H]DFP, and prior inactivation by DFP does not prevent reactions with [14C]BrPin.

  4. Observation of a re-entrant phase transition in the molecular complex tris(μ2-3,5-diisopropyl-1,2,4-triazolato-κ2N1:N2trigold(I under high pressure

    Christopher H. Woodall


    Full Text Available We report a molecular crystal that exhibits four successive phase transitions under hydrostatic pressure, driven by aurophilic interactions, with the ground-state structure re-emerging at high pressure. The effect of pressure on two polytypes of tris(μ2-3,5-diisopropyl-1,2,4-triazolato-κ2N1:N2trigold(I (denoted Form-I and Form-II has been analysed using luminescence spectroscopy, single-crystal X-ray diffraction and first-principles computation. A unique phase behaviour was observed in Form-I, with a complex sequence of phase transitions between 1 and 3.5 GPa. The ambient C2/c mother cell transforms to a P21/n phase above 1 GPa, followed by a P21/a phase above 2 GPa and a large-volume C2/c supercell at 2.70 GPa, with the previously observed P21/n phase then reappearing at higher pressure. The observation of crystallographically identical low- and high-pressure P21/n phases makes this a rare example of a re-entrant phase transformation. The phase behaviour has been characterized using detailed crystallographic theory and modelling, and rationalized in terms of molecular structural distortions. The dramatic changes in conformation are correlated with shifts of the luminescence maxima, from a band maximum at 14040 cm−1 at 2.40 GPa, decreasing steeply to 13550 cm−1 at 3 GPa. A similar study of Form-II displays more conventional crystallographic behaviour, indicating that the complex behaviour observed in Form-I is likely to be a direct consequence of the differences in crystal packing between the two polytypes.

  5. Thermodynamics of octane enhancing additives in gasolines: vapor-liquid equilibrium of the ternary system di-isopropyl ether (DIPE) + cyclohexane + benzene at 313.15 K; Thermodynamique d'additifs ameliorant l'index d'octane dans les essences: equilibre liquide-vapeur du systeme ternaire DIPE+cyclohexane+benzene a 313.15 K

    Chamorro, C.R.; Segovia, J.J.; Martin, M.C.; Villamanan, M.A. [Valladolid Univ., Lab. de Termodinamica, Dept. Ingenieria Energetica y Fluidomevanica E.T.S. de Ingenieros Industriales (Spain)


    Experimental isothermal P-x data at 313.15 K for the ternary system (di-isopropyl ether (DIPE) + cyclohexane + benzene) and for the two DIPE-binaries, DIPE + cyclohexane and DIPE = benzene, are reported. Data reduction by Barker's method provides correlations for g{sup E} using the Margules equation for the binary systems and the Wohl expansion for the ternary system. Wilson, NRTL and UNIQUAC models have been applied successfully to both the binary and the ternary systems. (authors)

  6. Bis[N,N′-bis­(2,6-diisopropyl­phen­yl)ethane-1,2-diimine]-1κ2 N,N′;2κ2 N,N′-tri-μ-trichlorido-1:2κ6 Cl:Cl-chlorido-1κCl-tetra­hydro­furan-2κO-dichromium(II) dichloro­methane 4.5-solvate

    Peitz, Stephan; Peulecke, Normen; Müller, Bernd H.; Spannenberg, Anke; Rosenthal, Uwe


    In the mol­ecular structure of the title compound, [Cr2Cl4(C26H36N2)2(C4H8O)]·4.5CH2Cl2, the two CrII centers are bridged by three Cl atoms, forming a dinuclear complex. Each CrII center is coordinated by one chelating bis­(2,6-diisopropyl­phen­yl)ethane-1,2-diimine ligand via both N atoms. An additional chloride ion binds to one chromium center, whereas an additional tetra­hydro­furan mol­ecule coordinates to the second CrII center. The coordination geometry at each CrII center can be best described as distorted octa­hedral. PMID:21578607

  7. Expression and post-translational processing of a broad-spectrum organophosphorus-neurotoxin-degrading enzyme in insect tissue culture

    Dave, K.I.; Phillips, L.; Luckow, V.A.; Wild, J.R.


    A recombinant baculovirus, Autographa californica nuclear polyhedrosis virus (AcNPV), has been utilized to express the opd (organophosphate-degrading) gene from Pseudomonas diminuta in insect tissue-culture cells (Sf9) of the fall armyworm (Spodoptera frugiperda). The broad-spectrum organophosphate hydrolase (EC encoded by this gene is a member of a general class of enzymes (organophosphate (OP) anhyorolases) that include parathion hydrolases, di-isopropyl-fluorophosphatases (DFpases), somanases, and OP phosphotrlesterases. This particular enzyme possesses the ability to hydrolyse paraoxon (P-O bond), DFP, sarin (P-F bond), VX (P-S bond) and tabun (P-CN bond), as well as a number of other extensively used organophosphorus pesticides. The enzyme produced in infected Sf9 cells is post-translationally processed and resembles the mature form of the enzyme expressed in various bacterial cells as identified by immunoprecipitation on Western blots. N-terminal sequence analysis of enzyme expressed in insect cells revealed Gly-29 as the terminal residue, whereas expression in Escherichia coli removes this residue, exposing Ser-30 at the N-terminus. Conditions for optimal expression of the enzyme in this system are described. Furthermore, hydrolytic efficiency of some OPs with purified enzyme from this system is discussed in relation to the in situ activity of Pseudomonas diminuta MG cells.

  8. Drinking Water Criteria for the Groundwater Pollutant Diisopropyl Methylphosphonate (DIMP).


    moderate corneal opacity lasting seven days, some conjunctival irritation, but no iritis . The aqueous suspension of DIMP produced no acute irritation...irritation studies conducted by the method of Draize show that technical grade DIMP produces moderate corneal opacity lasting seven days. No iritis was

  9. Effect of Diisopropyl Phosphorofluoridate in Some Aspects of Carbohydrate Metabolism

    A. K. Chatterjee


    Full Text Available An acute dose of DFP equivalent to 50 per cent of the LD50 cause glycogenolysis and hyperglycemia in male albino rats. The hyperglycemic effect can atleast be partially suppressed by the administration of insulin. Under sub-acute dose equivalent to 5 per cent of the LD50, there is glycogenolysis but no change is blood glucose. The action of DFP on carbohydrate metabolism seems to be mediated through adrenal gland. DFP also increases the glycolytic rate, suppresses the LDH activity and is hepatotoxic.

  10. 78 FR 33748 - Diisopropyl Adipate; Exemption From the Requirement of a Tolerance


    ... Cosmetic Act (FFDCA), requesting establishment of an exemption from the requirement of a tolerance. This.... Department of Agriculture's National Health and Nutrition Examination Survey, What we eat in America,...

  11. (2,6-Diisopropyl-phen-yl)(2-thienylmethyl-ene)amine.

    Imhof, Wolfgang


    The title compound, C(17)H(21)NS, was prepared by the condensation of thio-phene-2-carbaldehyde with 2,6-diiso-propyl-aniline. It crystallizes with two mol-ecules in the asymmetric unit. The mol-ecules are inter-connected via a C-H⋯N hydrogen bond. The dihedral angles between the thio-phene and phenyl rings are 81.7 (7) and 85.5 (7)°.

  12. Experimental and theoretical investigation of the complexation of methacrylic acid and diisopropyl urea

    Pogány, Peter; Razali, Mayamin; Szekely, Gyorgy


    The present paper explores the complexation ability of methacrylic acid which is one of the most abundant functional monomer for the preparation of molecularly imprinted polymers. Host-guest interactions and the mechanism of complex formation between methacrylic acid and potentially genotoxic 1,3-diisopropylurea were investigated in the pre-polymerization solution featuring both experimental (NMR, IR) and in silico density functional theory (DFT) tools. The continuous variation method revealed the presence of higher-order complexes and the appearance of self-association which were both taken into account during the determination of the association constants. The quantum chemical calculations - performed at B3LYP 6-311 ++G(d,p) level with basis set superposition error (BSSE) corrections - are in agreement with the experimental observations, reaffirming the association constants and justifying the validity of computational investigation of such systems. Furthermore, natural bond orbital analysis was carried out to appraise the binding properties of the complexes.

  13. Toxicology Study of Diisopropyl Methylphosphonate and Dicyclopentadiene in Mallard Ducks, Bobwhite Quail and Mink.


    15.6*C. Eggs were set once a week in a Jamesway , single stage, 252 incubator. 3 The eggs were incubated for 23 days at an average temperature of 37.5*C... Jamesway stage Model 252 incubator. 3 The incubator was maintained at an average internal temperature of 37.5’C (range 36.9 to 38.1 0 C) and average...into pedigree hatching baskets and were transferred to a hatching unit ( Jamesway Model 252) on day 21. The average temperature and relative humidity

  14. (E-N,N-Diethyl-2,6-diisopropyl-4-[2-(4-nitrophenylethenyl]aniline

    Heiner Detert


    Full Text Available The title compound, C24H32N2O2, was prepared by Horner olefination of 4-diethylamino-3,5-diisopropylbenzaldehyde and diethyl p-nitrobenzylphosphonate. There are two independent molecules (A and B in the asymmetric unit. Their main axes, defined by the line connecting the N atoms of the nitro and amino groups, open an angle of 79.42 (3°. Steric hindrance around the amino group is reflected in a long aryl C—N bond [1.434 (3 Å for molecule A and 1.440 (3 Å for molecule B], a pyramidal geometry [angle sum = 350.0 (2° for molecule A and 349.6 (2° for molecule B], and dihedral angles between the phenylene group and the plane defined by the CH2—N—CH2 unit of 86.9 (3° for molecule A and 88.3 (3° for molecule B. This gives structural support for the electronic decoupling of the amino group from the nearly planar nitrostilbene moiety (r.m.s. deviation for C, N and O atoms = 0.097 for molecule A and 0.107 Å for molecule B.

  15. Syntheses and structures of dimeric sodium and potassium complexes of 2,6-diisopropyl-anilidophosphine borane ligand

    Kishor Naktode; Jayeeta Bhattacharjee; Anirban Chakrabarti; Tarun K Panda


    We report here the syntheses and structural studies of dimeric sodium and potassium complexes of composition [Na(THF)2{Ph2P(BH3)N(2,6-iPr2C6H6)}]2 (2) and [K(THF)2{Ph2P(BH3)N(2,6-iPr2C6H6)}]2(3). The sodium complex 2 was readily prepared by the reaction of sodium bis(trimethylsilyl)amide with 2,6-diisopropylanilidophosphine-borane ligand [2,6-iPr2C6H3NHP(BH3)Ph2] (1-H) at ambient temperature. The potassium complex 3 was prepared by two synthetic routes: in the first method, the ligand 1-H was made to react with potassium hydride at room temperature to afford the corresponding potassium complex. The potassium bis(trimethylsilyl)amides were made to react with protic ligand 1-H in the second method to eliminate the volatile bis(trimethyl)silyl amine. Solid-state structures of both the new complexes were established by single crystal X-ray diffraction analysis. In the molecular structures of complexes 2, the sodium metal is coordinated by the anilido nitrogen (1) and borane group (1) attached to the phosphorus atom of ligand 1. In contrast, for compound 2, ligand 1 displays 6-arene interaction from 2,6-diisopopylphenyl ring with potassium atom along with 3 interaction of BH3 group due to larger ionic radius of potassium ion.

  16. N,N-Diisopropyl-N-phosphonyl Imines Lead to Efficient Asymmetric Synthesis of Aziridine-2-Carboxylic Esters

    Kattamuri, Padmanabha V.; Xiong, Yiwen; Pan, Yi; Li, Guigen


    Highly diastereoselective asymmetric synthesis of chiral aziridine-2-carboxylic esters is reported for 20 examples with good yields (51–87%) and excellent diastereoselectivities (>99:1 dr for most cases). The modified N-phosphonyl imines are proven to be superior to previous imine auxiliaries for the aza Darzens reaction by using secondary isopropyl to replace primary benzyl group for N,N-diamino protection. In the meanwhile, a special operation by slowly adding the pre-cooled imine solution at −78 °C into the preformed β-bromo lithium enolate mixture at this temperature in the presence of 4 Å molecular sieves was found to be crucial in terms of yields and diastereoselectivity. The present method can provide an easy and general access to β-hydroxy α-amino acids and other important amino building blocks. PMID:23563304

  17. Thermodynamic modeling of ternary and quaternary (liquid + liquid) systems containing water, FeCl3, HCl and diisopropyl ether

    Milosevic, M.; Hendriks, I.; Smits, R.E.R.; Schuur, Boelo; de Haan, A.B.


    Liquid–liquid extraction using ethers as solvents is a potentially energy saving alternative for the concentration of aqueous ferric chloride solutions. Adequate thermodynamic models that describe the behavior of the resulting quaternary systems (FeCl3, ether, acid and water) are not available in

  18. Diisopropyl {[(R-2-(2-amino-6-chloro-9H-purin-9-yl-1-methylethoxy]methyl}phosphonate

    Guobao Zhao


    Full Text Available In the title compound, C15H25ClN5O4P, the r.m.s. deviation for the purine ring system is 0.0165 Å. The coordination about the P atom is a distorted tetrahedron [O=P—O angles = 116.70 (6 and 109.87 (6°]. In the crystal, molecules are linked by N—H...O hydrogen bonds, generating a three-dimensional network.

  19. Solution and computed structure of O-lithium N,N-diisopropyl-P,P-diphenylphosphinic amide. Unprecedented Li-O-Li-O self-assembly of an aryllithium.

    Fernández, Ignacio; Oña-Burgos, Pascual; Oliva, Josep M; Ortiz, Fernando López


    The structural characterization of an ortho-lithiated diphenylphosphinic amide is described for the first time. Multinuclear magnetic resonance ((1)H, (7)Li, (13)C, (31)P) studies as a function of temperature and concentration employing 1D and 2D methods showed that the anion exists as a mixture of one monomer and two diastereomeric dimers. In the dimers the chiral monomer units are assembled in a like and unlike manner through oxygen-lithium bonds, leading to fluxional ladder structures. This self-assembling mode leads to the formation of Li(2)O(2) four-membered rings, a structural motif unprecedented in aryllithium compounds. DFT computations of representative model compounds of ortho-lithiated phosphinic amide monomer and Li(2)C(2) and Li(2)O(2) dimers with different degrees of solvation by THF molecules showed that Li(2)O(2) dimers are thermodynamically favored with respect to the alternative Li(2)C(2) structures by 4.3 kcal mol(-1) in solvent-free species and by 2.3 kcal mol(-1) when each lithium atom is coordinated to one THF molecule. Topological analysis of the electron density distribution revealed that the Li(2)O(2) four-membered ring is characterized by four carbon-lithium bond paths and one oxygen-oxygen bond path. The latter divides the Li-O-Li-O ring into two Li-O-Li three-sided rings, giving rise to two ring critical points. On the contrary, the bond path network in the Li(2)C(2) core includes a catastrophe point, suggesting that this molecular system can be envisaged as an intermediate in the formation of Li(2)O(2) dimers. The computed (13)C chemical shifts of the C-Li carbons support the existence of monomeric and dimeric species containing only one C-Li bond and are consistent with the existence of tricoordinated lithium atoms in all species in solution.

  20. Synaptic Mechanisms of Action of Convulsion-Producing Anticholinesterases. Characterization of Di-Isopropyl Phosphorofluoridate-Induced Epileptiform Activity in the Mammalian Hippocampus.


    EPSP followed by a longer-lasting IPSP [51], which is presumably due to the recurrent excitation of inhibitory interneurons [57]. A calcium-dependent...of the theoretical discharge frequency versus 30 the preset average EPSP amplitude. TABLES 1. Effects of various pharmacological agents on or near 0 mV [9,18], a result which would indicate that an excitatory postsynaptic potential ( EPSP ) is responsible for pro- ducing these

  1. [1,2-Bis(diisopropyl­phosphan­yl)ethane-κ2 P,P′](carbonato-κ2 O,O′)nickel(II)

    Morales-Becerril, Illan; Flores-Alamo, Marcos; Garcia, Juventino J.


    In the crystal of the title compound, [Ni(CO3)(C14H32P2)], the metal center in each of three independent mol­ecules shows slight tetra­hedral distortion from ideal square-planar coordination geometry, with angles between the normals to the planes defined by the cis-P—Ni—P and cis-O—Ni—O fragments of 3.92 (17), 0.70 (16) and 2.17 (14)° in the three mol­ecules. In the crystal, there are inter­molecular C—H⋯O hydrogen bonds that show a laminar growth in the ab plane. PMID:23633999

  2. Hydrolase stabilization via entanglement in poly(propylene sulfide) nanoparticles: stability towards reactive oxygen species

    Allen, Brett L.; Johnson, Jermaine D.; Walker, Jeremy P.


    In the advancement of green syntheses and sustainable reactions, enzymatic biocatalysis offers extremely high reaction rates and selectivity that goes far beyond the reach of chemical catalysts; however, these enzymes suffer from typical environmental constraints, e.g. operational temperature, pH and tolerance to oxidative environments. A common hydrolase enzyme, diisopropylfluorophosphatase (DFPase, EC, has demonstrated a pronounced efficacy for the hydrolysis of a variety of substrates for potential toxin remediation, but suffers from the aforementioned limitations. As a means to enhance DFPase’s stability in oxidative environments, enzymatic covalent immobilization within the polymeric matrix of poly(propylene sulfide) (PPS) nanoparticles was performed. By modifying the enzyme’s exposed lysine residues via thiolation, DFPase is utilized as a comonomer/crosslinker in a mild emulsion polymerization. The resultant polymeric polysulfide shell acts as a ‘sacrificial barrier’ by first oxidizing to polysulfoxides and polysulfones, rendering DFPase in an active state. DFPase-PPS nanoparticles thus retain activity upon exposure to as high as 50 parts per million (ppm) of hypochlorous acid (HOCl), while native DFPase is observed as inactive at 500 parts per billion (ppb). This trend is also confirmed by enzyme-generated (chloroperoxidase (CPO), EC reactive oxygen species (ROS) including both HOCl (3 ppm) and ClO2 (100 ppm).

  3. Enhancing bioplastic-substrate interaction via pore induction and directed migration of enzyme location.

    Lele, Bhalchandra S; Papworth, Glenn; Katsemi, Vicky; Rüterjans, Heinz; Martyano, Igor; Klabunde, Kenneth J; Russell, Alan J


    We demonstrate two novel approaches to enhance interactions of polymer-immobilized biomolecules with their substrates. In the first approach, diisopropylfluorophosphatase (DFPase) containing poly(urethane) (PU) coatings were made microporous by incorporating, then extracting, poly(ethylene glycol)-based diesters as porogens. Incorporation of 2% w/w porogen increased the effective diffusion coefficient of diisopropylfluorophosphate (DFP) through the coatings by 30% and increased the apparent turnover number of immobilized DFPase 3-fold. In the second approach, prior to immobilization, hydrophobic modification of DFPase was achieved through its conjugation with a dimer/trimer mixture of a uretdione based on 1,6-diisocyanatohexane. When the hydrophobically modified DFPase was immobilized in coatings, catalytic activity was 4-fold higher than that of the equivalent, immobilized, native DFPase. This activity enhancement was independent of the presence or absence of pores. Confocal microscopy images of coatings containing fluorescently labeled lysozyme show that the native enzyme is distributed uniformly over the entire thickness of the coatings. Hydrophobically modified and fluorescently labeled lysozyme is accumulated only in the upper 10 microm cross-sectional layer of a 100 microm-thick coating. Interactions of bioplastics with their substrates are tunable either by pore induction in a polymer or by directed migration of the hydrophobically modified biomolecule to the desired location. The latter approach has broad implications, including overcoming mass transfer limitations experienced by immobilized biocatalysts.

  4. Purification and properties of dialkylfluorophosphatase

    Cohen, J.A.; Warringa, M.G.P.J.


    1. 1. Zone electrophoresis on starch columns of purified preparations of fluorophosphatase resulted in a further purification. The preparations thus obtained differed in various respects from the cruder ones so far described. 2. 2. In the course of this electrophoresis fractions were obtained, which

  5. 水-醋酸-二异丙醚三元体系液液相平衡数据的测定%Measurement of Liquid-Liquid Equilibrium Data for the Ternary System of Water + Acetic acid + Diisopropyl Ether

    庄六星; 白璐


    实验测定了水-醋酸-二异丙醚三元体系在293.15 K、303.15 K的液液相平衡数据.分别采用Othmer-Tobias和Bachman方程对实验数据进行了可靠性检验,相关性系数均大于0.983.绘制了三元液液平衡相图.

  6. CCDC 999049: Experimental Crystal Structure Determination : (1,3-bis(2,6-Di-isopropyl-4-methoxyphenyl)imidazolidin-2-ylidene)-dichloro-(3-phenyl-1H-inden-1-ylidene)-triphenylphosphine-ruthenium n-pentane solvate

    Manzini, Simone


    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  7. CCDC 1431673: Experimental Crystal Structure Determination : dibromo-(P,P-di-t-butyl-N-(6-(3,5-diisopropyl-1H-pyrazol-1-yl)pyridin-2-yl)phosphinous amide)-cobalt

    Gong, Dirong


    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  8. CCDC 813378: Experimental Crystal Structure Determination : trans-bis(1,3-Di-isopropyl-2,3-dihydro-1H-benzimidazol-2-ylidene)-bis(thiocyanato)-nickel

    Jothibasu, R.


    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  9. {2,6-Bis[(2,6-diisopropyl-phosphan-yl)-oxy]-4-fluoro-phenyl-κ(3)P,C(1),P'}(1H-pyrazole-κN(2))nickel(II) hexa-fluoro-phosphate.

    Kwan, Man-Lung; Conry, Sara J; Carfagna, Charles S; Press, Loren P; Ozerov, Oleg V; Hoffman, Norris W; Sykora, Richard E


    The title compound, [Ni(C(18)H(30)FO(2)P(2))(C(3)H(4)N(2))]PF(6), was prepared by halide abstraction with TlPF(6) in the presence of CH(3)CN in CDCl(3) from the respective neutral pincer chlorido analogue followed by addition of pyrazole. The PO-C-OP pincer ligand acts in typical trans-P(2) tridentate fashion to generate a distorted square-planar nickel structure. The Ni-N(pyrazole) distance is 1.925 (2) Å and the plane of the pyrazole ligand is rotated 56.2 (1)° relative to the approximate square plane surrounding the Ni(II) center in which the pyrazole is bound to the Ni(II) atom through its sp(2)-hybridized N atom. This Ni-N distance is similar to bond lengths in the other reported Ni(II) pincer-ligand square-planar pyrazole complex structures; however, its dihedral angle is significantly larger than any of those for the latter set of pyrazole complexes.

  10. CCDC 849284: Experimental Crystal Structure Determination : Dichloro-(2,6-diisopropyl-N-(1-(6-(1H-pyrazol-1-yl)pyridin-2-yl)ethylidene)aniline)-cobalt(ii)

    Gong, Dirong


    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  11. Deactivating Chemical Agents Using Enzyme-Coated Nanofibers Formed by Electrospinning


    surface7, 17, 24 can be performed to improve the surface chemistry for enzyme attachment and subsequent increased enzyme activity. Another well-known...for the electrospinning were prepared by dissolving DFPase (3 wt.%) and PEO (3 wt.%) into DI water. Sodium dodecyl sulfate (SDS) surfactant was

  12. Design and Construction of a High Vacuum Surface Analysis Instrument to Study Chemistry at Nanoparticulate Surfaces


    XPS Aerogel Prepared Conventionally Prepared Chemical Weapon Chemical Warfare Agent Diisopropyl Fluorophosphate Diisopropyl Methylphosphonate...have shown promise as effective decontamination reactants that do not possess the shortcomings of solution- based strategies. In particular, gold ...have also been investigated.16 Recent studies have demonstrated catalytic degradation of DMMP by titania-supported gold nanoparticles.17 9

  13. Bioinspired Surface Treatments for Improved Decontamination: Silicate-Based Slippery Liquid-Infused Porous Surfaces (SLIPS)


    environment including contamination avoidance, individual protection, collective protection, and decontamination. In January 2015, the Center for Bio...methyl salicylate, dimethyl methylphosphate, and diisopropyl fluorophosphates following treatment of contaminated surfaces with a soapy water solution...and diisopropyl fluorophosphate following treatment of contaminated surfaces with a soapy water solution is reported along with droplet diffusion on

  14. Neurochemical Mechanism of Organophosphorus Compounds: Effect on Neuromembrane.


    In vivo administration of tritiated leucine. To study the effects of OP’s on brain protein synthesis, we used intracerebroventricular ( administration of tritiated leucine 7 DFP analysis 8 AChE assay 8 DFPase assay 8 DFP binding 8 Materials 9 Animals 9 RESULTS 9 Brain Protein...some bands was altered by DFP administration . ". Inactivation of DFP by Brain Tissue. When DFP was incubated at 370 C with mouse brain homogenates, a

  15. Interaction between N-Phospho-Amino Acids and Nucleoside in Aqueous Medium


    Nucleosides were phosphorylated with different N- (O, O-diisopropyl) phosphoryl amino acids to give nucleoside mono phosphates in aqueous solution. 2', 3', and 5'-isomers had been confirmed by comparison with authentic samples on the basis of HPLC analysis. The conversion percentage of nucleoside indicated that N- (O, O-diisopropyl) phosphoryl aspartic acid reacted with adenosine and guanosine at a much higher rate than other kinds of N- phosphoryl amino acids, while phosphorylation of cytidine and uridine was relatively easy by using N- (O, O-diisopropyl) phosphoryl threonine. The result could give some clue to the prebiotic code origin of nucleic acid and protein.

  16. Long-chain ethers as solvents can amplify the enantioselectivity of the Carica papaya lipase-catalyzed transesterification of 2-(substituted phenoxy)propanoic acid esters.

    Miyazawa, Toshifumi; Iguchi, Wakana


    The enantioselectivity of the transesterification of the 2,2,2-trifluoroethyl esters of 2-(substituted phenoxy)propanoic acids, as catalyzed by the lipase from Carica papaya, was greatly improved by using long-chain ethers, such as di-n-hexyl ether, as solvents instead of the conventional diisopropyl ether. Thus, for example, the E value was enhanced from 21 [in diisopropyl ether (0.8 ml)] to 57 [in di-n-hexyl ether (0.8 ml)] in the reaction of 2,2,2-trifluoroethyl(RS)-2-phenoxypropanoate (0.1 mmol) with methanol (0.4 mmol) in the presence of the plant lipase preparation (10 mg); it was also improved from 13 (in diisopropyl ether) to 44 (in di-n-hexyl ether) in the reaction of 2,2,2-trifluoroethyl(RS)-2-(2-chlorophenoxy)propanoate with methanol under the same reaction conditions.

  17. Phytochemical examination of Prosopis cineraria L.(druce leaves

    Malik Archana


    Full Text Available The phytochemical studies on the leaves of Prosopis cineraria resulted in isolation of methyl docosanoate, diisopropyl-9,10-dihydroxyicosane-1,20-dioate, tricosan-1-ol and 7,24-tirucalladien-3-one. While diisopropyl-10,11-dihydroxyicosane-1,20-dioate is a hitherto unreported compound, methyl docosanoate, tricosan-1-ol and 7,24-tirucalladien-3-one are being reported for the first time from P. cineraria . These compounds have been characterized on the basis of spectral and other data.

  18. Phytochemical examination of Prosopis cineraria L.(druce) leaves

    Malik Archana; Kalidhar S


    The phytochemical studies on the leaves of Prosopis cineraria resulted in isolation of methyl docosanoate, diisopropyl-9,10-dihydroxyicosane-1,20-dioate, tricosan-1-ol and 7,24-tirucalladien-3-one. While diisopropyl-10,11-dihydroxyicosane-1,20-dioate is a hitherto unreported compound, methyl docosanoate, tricosan-1-ol and 7,24-tirucalladien-3-one are being reported for the first time from P. cineraria . These compounds have been characterized on the basis of spectral and other data.

  19. Analysis of VX nerve agent hydrolysis products in wastewater effluents by ion chromatography with amperometric and conductivity detection.

    Piao, Haishan; Marx, Randall B; Schneider, Steven; Irvine, David A; Staton, John


    An analytical method, based on the use of ion chromatography, was developed to monitor the levels of three regulated VX hydrolysis products in the effluent from a biological wastewater treatment process--ethylmethylphosphonic acid, methylphosphonic acid and 2-(diisopropyl)aminoethanethiol. Previous methods have not been applied to wastewater matrices or 2-(diisopropyl)aminoethanethiol. Despite the specificity and sensitivity constraints of this method, it was possible to measure the compounds in bioreactor effluents down to a level substantially below the US Army discharge limit of 0.1% (w/v). Analytical data was confirmed by liquid chromatography-mass spectrometry (LC-MS) at an independent laboratory.

  20. Computer controlled infusion of propofol for conscious sedation in dental treatment.

    Oei-Lim, V.L.B.; Kalkman, C.J.; Makkes, P.C.; Ooms, W.G.; Hoogstraten, J.


    To assess a drug delivery system that can rapidly achieve and maintain a constant blood concentration of Propofol (2,6 di-isopropyl phenol) which, in subanaesthetic doses, is an effective intravenous sedative for treating anxious or handicapped patients in dentistry:Design The clinical use of a

  1. Regio- and stereoselective hydrosilylation of immobilized terminal alkynes

    Pedersen, Palle Jacob; Henriksen, Jonas; Gotfredsen, Charlotte Held;


    Regio- and stereoselective hydrosilylation of terminal alkynes on solid support using diisopropyl hydrosilanes yielding b-(E)-vinyl silanes with excellent selectivity is reported. The hydrosilylation is catalyzed by Pt(DVDS)/P(iBuNCH2CH2)3N (DVDS = 1,3-divinyl-1,1,3,3-tetramethyl-disiloxane), in ...

  2. Computer controlled infusion of propofol for conscious sedation in dental treatment.

    Oei-Lim, V.L.B.; Kalkman, C.J.; Makkes, P.C.; Ooms, W.G.; Hoogstraten, J.


    To assess a drug delivery system that can rapidly achieve and maintain a constant blood concentration of Propofol (2,6 di-isopropyl phenol) which, in subanaesthetic doses, is an effective intravenous sedative for treating anxious or handicapped patients in dentistry:Design The clinical use of a comp

  3. Senescence Marker Protein 30 (SMP30) Expression in Eukaryotic Cells: Existence Of Multiple Species and Membrane Localization


    disiopropylfluorophosphate (DFP) and chemical warfare nerve agents including soman, sarin, VX, and tabun [19–21]. In addition, SMP30 knock-out mice lacked...Talbot MK, Boucher LJ, MacIver B, et al. (1989) Partial characterization of an enzyme that hydrolyzes sarin, soman, tabun , and diisopropyl

  4. Different effects of propofol and nitrosopropofol on DMPC multilamellar liposomes.

    Momo, Federico; Fabris, Sabrina; Bindoli, Alberto; Scutari, Guido; Stevanato, Roberto


    The mechanisms of reaction of propofol with nitrosoglutathione lead to the formation of an active species which was identified, and then synthesised, as 2,6-diisopropyl-4-nitrosophenol. In the present work, we demonstrate the in vitro formation of 2,6-diisopropyl-4-nitrosophenol, then we discuss the interaction of propofol and 2,6-diisopropyl-4-nitrosophenol with dimyristoylphosphatidylcholine and egg yolk phosphatidylcholine multilamellar liposomes using differential scanning calorimetry and spin labelling techniques. It was demonstrated that both molecules are highly lipophylic and absorb almost entirely in the lipid phase. The thermotropic profiles showed that these molecules affect the temperature and the co-operativity of the gel-to-fluid state transition of the liposomes differently: the effects of 2,6-diisopropylphenol on the lipid organisation are quite similar to phenol and coherently interpretable in terms of the disorder produced in the membrane by a bulky group; 2,6-diisopropyl-4-nitrosophenol is a stronger perturbing agent, and ESR spectra suggest that this is due to a relative accumulation of the molecule into the interfacial region of the bilayer.

  5. Application of Solid Phase Microextraction with Gas Chromatography-Mass Spectrometry as a Rapid, Reliable, and Safe Method for Field Sampling and Analysis of Chemical Warfare Agent Precursors


    nations, including plating solutions, metallurgical processes such as silver and gold refining, and as an intermediate in the manufacture of resin...used in numerous processes in industrial nations, including plating and other metallurgical processes such as silver and gold refining, and as an...malononitrile, diisopropyl methylphosphonate (DIMP), diethyl methylphosphonate (DEMP), malathion, potassium cyanide , and O,O’diethyl methyl

  6. Intermolecular Phosphoryl Transfer Between Serine and Histidine Residues

    Yu Qian SU; Ming Yu NIU; Shu Xia CAO; Jian Chen ZHANG; Yu Fen ZHAO


    A novel intermolecular phosphoryl transfer from O-trimethylsilyl-N-(O, O-diisopropyl) phosphoryl serine trimethylsilyl ester to N, N'-bis(trimethylsilyl) histidine trimethylsilyl ester was studied through electrospray ionization mass spectrometry (ESI-MS). It was proposed that the transfer reaction went through penta-coordinated phosphorus intermediate.

  7. Development of a Model for Nerve Agent Inhalation in Conscious Rats


    Toxicol Mech Meth 14:183–94. Bajgar J. (2004). Organophosphates /nerve agent poisoning : mechanism of action, diagnosis, prophylaxis, and treatment. Adv...See reprint. 15. SUBJECT TERMS Chemical warfare, cholinesterases, inhalation exposure, nerve agents, organophosphates , vapor 16. SECURITY...exposure system for assessing respiratory toxicity of vaporized chemical agents in untreated, non-anesthetized rats. The organophosphate diisopropyl

  8. Computer controlled infusion of propofol for conscious sedation in dental treatment.

    Oei-Lim, V.L.B.; Kalkman, C.J.; Makkes, P.C.; Ooms, W.G.; Hoogstraten, J.


    To assess a drug delivery system that can rapidly achieve and maintain a constant blood concentration of Propofol (2,6 di-isopropyl phenol) which, in subanaesthetic doses, is an effective intravenous sedative for treating anxious or handicapped patients in dentistry:Design The clinical use of a comp

  9. A Facile Synthesis of N-Phosphoryl Amino Acids Containing Hydroxy Group

    Jian Chen ZHANG; Shu Xia CAO; Xiao Li YANG; Yu Fen ZHAO


    three kinds of N-(diisopropyloxyphosphoryl) amino acids containing hydroxyl group were prepared in high yield by using diisopropyl phosphite as the phosphorylating agent, sodium hypochlorite as the chlorinating agent and tetrabutyl ammonium bromide as the phase transfer catalyst in basic aqueous media.

  10. Ketene formation from aliphatic ketones in a silent electrical discharge

    Drumpt, J.D. van; Mackor, A.


    The title reaction in the plasma of a silent electrical discharge at 40° is described. Acetone, ethyl methyl ketone, diethyl ketone and diisopropyl ketone all give rise to the formation of ketenes. From these ketones not only is the corresponding ketene formed, but the lower ketenes also, presumably

  11. Waste Water Handling Proof of Concepts at McMurdo Station, Antarctica


    2-Chlorotoluene Diisopropyl ether trans-1,3-Dichloropropene 2-Hexanone Ethyl acetate Trichloroethene 4-Ethyltoluene Ethylbenzene...Trichlorofluoromethane 4-Methyl-2-pentanone Ethyl tert-butyl ether Trichlorotrifluoroethane Acetone Heptane Vinyl acetate Acetonitrile Hexachlorobutadiene Vinyl... production at the runway was limited before the start of these projects and was estimated to determine proper sizing of the two methods used. During

  12. 40 CFR 79.56 - Fuel and fuel additive grouping system.


    ... occurring in non-baseline gasoline formulations include ethanol, methyl tertiary butyl ether (MTBE), ethyl tertiary butyl ether (ETBE), tertiary amyl methyl ether (TAME), diisopropyl ether (DIPE), dimethyl ether (DME), tertiary amyl ethyl ether (TAEE), and any other compound(s) which increase the oxygen content...

  13. Synthesis and characterization of oxovanadium (IV) dithiocarbamates with pyridine

    Doadrio, Antonio L.; Sotelo, Jose; Fernandez-Ruano, Ana [Universidad Complutense, Madrid (Spain). Facultad de Farmacia. Dept. de Quimica Inorganica y Bioinorganica]. E-mail:


    We report the synthesis and study of a new series of oxovanadium (IV) dithiocarbamate adducts and derivatives with pyridine and cyclohexyl, di-iso-butyl, di-n-propyl, aniline, morpholine, piperidine and di-iso-propyl amines. The complexes have been characterized by analytical, magneto chemical, IR, visible-UV spectral and thermal studies, and are assigned the formulas [VO(L){sub 2}].py, where L=cyclohexyl, di-iso-butyl, di-n-propyl, aniline dithiocarbamate and [VO(OH)(L)(py){sub 2}] OH.H{sub 2}O (L=morpholine, piperidine and di-iso-propyl dithiocarbamate). The effect of the adduct formation on the p{sub V=0} bound is discussed in terms of the IR (V=O, V-S and V-N stretching frequencies) and electronic spectra (d-d transitions). (author)

  14. Process for the preparation of cumene

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


    Cumene is produced in a catalyst bed under 0.25 to 50 atmospheres of pressure and at temperatures in the range of C. to C., using as the catalyst a mole sieve characterized as acidic by feeding propylene to the catalyst bed while benzene is conveniently added through the reflux to result in a molar excess present in the reactor to that required to react with propylene, thereby reacting substantially all of the propylene and recovering benzene as the principal overhead and cumene and diisopropyl benzene in the bottoms. The bottoms are fractionated, the cumene recovered and the bottoms are contacted with benzene in the liquid phase in a fixed bed straight pass reactor under conditions to transalkylate the benzene thereby converting most of the diisopropyl benzene to cumene which is again separated and recovered.

  15. Synthesis and characterization of oxovanadium (IV dithiocarbamates with pyridine

    Antonio L. Doadrio


    Full Text Available We report the synthesis and study of a new series of oxovanadium (IV dithiocarbamate adducts and derivatives with pyridine and cyclohexyl, di-iso-butyl, di-n-propyl, anilin, morpholin, piperidin and di-iso-propyl amines. The complexes have been characterized by analytical, magnetochemical, IR, visible-UV spectral and thermal studies, and are assigned the formulas [VO(L2].py, where L=cyclohexyl, di-iso-butyl, di-n-propyl, anilin dithiocarbamate and [VO(OH(L(py2]OH.H2O (L=morpholin, piperidin and di-iso-propyl dithiocarbamate. The effect of the adduct formation on the pV=0 bound is discussed in terms of the IR (V=O, V-S and V-N stretching frequencies and electronic spectra (d-d transitions.

  16. Proficiency of acceptor-donor-acceptor organic dye with spiro-MeOTAD HTM on the photovoltaic performance of dye sensitized solar cell

    Ramavenkateswari, K.; Venkatachalam, P.


    This work investigates the proficiency of acceptor-donor-acceptor (A-D-A) organic dye Diisopropyl azodicarboxylate (DIAC) as photosensitizer on the photovoltaic parameters of silver (Ag) doped TiO2 photoanode dye-sensitized solar cells (DSSCs) with quasi-solid state electrolyte/hole transport material (HTM) spiro-MeOTAD. TNSs (TiO2 nanosticks) photoanodes are prepared through sol-gel method and hydrothermal technique. X-ray powder diffraction (XRD), transmission electron microscope (TEM), scanning electron microscopy (SEM) and BET measurement were used to characterize the structure and morphology of TiO2 nanostructures. The Diisopropyl azodicarboxylate organic dye with TNPs-Ag@TNSs composite photoanode structure and spiro-MeOTAD HTM exhibited better power conversion efficiency (PCE).

  17. Desenvolvimento de sistemas líquido-cristalinos empregando silicone fluido de co-polímero glicol e poliéter funcional siloxano

    Chorilli, Marlus; Prestes, Paula Souza; Rigon, Roberta Balansin; Leonardi, Gislaine Ricci; Chiavacci, Leila Aparecida; Scarpa,Maria Virgínia


    For the construction of the phase diagrams, the method of the aqueous titration was used. There were prepared 5 ternary diagrams, varying the surfactant and the oil phase. The liquid-crystalline phases were identified by polarized light microscopy. The formulations prepared with silicon glycol copolymer, polyether functional siloxane (PFS) and water (S1) and with diisopropyl adipate, PFS and water (S4) presented liquid-crystalline phases with lamellar arrangement. Moreover, after 15 days in h...

  18. Human platelet aggregation inhibitors from thyme (Thymus vulgaris L.).

    Okazaki, Kenji; Kawazoe, Kazuyoshi; Takaishi, Yoshihisa


    Two antiaggregant compounds, thymol (compound 1) and 3,4,3',4'-tetrahydroxy-5,5'-diisopropyl-2,2'-dimethylbiphenyl (compound 2) were isolated from the leaves of thyme (Thymus vulgaris L.). The structures were determined by (1)H-, (13)C-NMR and mass spectra (MS) studies. These compounds inhibited platelet aggregation induced by collagen, ADP, arachidonic acid (AA) and thrombin except that compound 2 did not inhibit platelet aggregation induced by thrombin.

  19. Understanding Gulf War Illness: An Integrative Modeling Approach


    Repeating this propagation analysis for all 26 markers we found:  Important trigger effects for several markers in blood and brain in response to LPS...Computational Biology Cytokines Deregulated Balance Diisopropyl Phosphorofluoridate Drug Treatment Electrocardiogram Exercise Physiology Gulf War Illness...continue 30% Conduct wheel running acute and chronic exercise tests to simulate the exercise model in humans 4-12 25% Combine tests of acute and

  20. [3 + 2]-Cycloadditions of nitrile ylides after photoactivation of vinyl azides under flow conditions

    Stephan Cludius-Brandt


    Full Text Available The photodenitrogenation of vinyl azides to 2H-azirines by using a photoflow reactor is reported and compared with thermal formation of 2H-azirines. Photochemically, the ring of the 2H-azirines was opened to yield the nitrile ylides, which underwent a [3 + 2]-cycloaddition with 1,3-dipolarophiles. When diisopropyl azodicarboxylate serves as the dipolarophile, 1,3,4-triazoles become directly accessible starting from the corresponding vinyl azide.

  1. Ultra-microporous triptycene-based polyimide membranes for high-performance gas separation

    Ghanem, Bader


    A highly permeable and highly selective polyimide of intrinsic microporosity is prepared using a 9,10-diisopropyl-triptycene contortion center. The three-dimensionality and shape-persistence of triptycene afford exceptional sieving-based gas separation performance transcending the latest permeability/selectivity trade-offs for industrial gas separations involving oxygen and hydrogen. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Candida rugosa Lipase-catalyzed Kinetic Resolution of Hydroxyalkanephosphonates

    张永辉; 徐成富; 李晋峰; 袁承业


    An efficient lipase-catalyzedenantioselective hydrolysis of butyryloxyalkanephosphonates in water-equillbrated diisopropyl ether was developed. The relationship between the substrates' structure and the reactivity, as well as the enantioselectivlty of this enzymatic transformation was studied. The catalytic preference of crude Candida rugosa lipase toward such molecules was assigned according to modified Mosher's method and Xray crystallographic analysis. Optically pure 2-hydroxy-2-arylethanephosphonates, 3-hydroxy-3-phenylpropanephosphonate, and 3, 3, 3-trifluoro-2-hydroxypropanephosphonates were conveniently prepared in this manner.

  3. An efficient yttrium catalysed version of the "Aufbaureaktion" for the synthesis of terminal functionalised polyethylene

    Kretschmer, Winfried P.; Bauer, Tobias; Hessen, Bart; Kempe, Rhett


    The cationic lanthanoid alkyl complexes (NCN)YR(THF)(+) (R = CH(2)SiMe(3)) bearing a NCN-ligand based on N,N'-bis(2,6-diisopropylphenyl)-benzamidine (AmH), N-[ 6-(2,4,6-triisopropyl-phenyl)-pyridin-2-yl]-(2,6-diisopropyl)aniline (ApH) or 1,3-bis(2,6-diisopropylphenyl)-2,2-dimethylguanidine (GuaH) co


    Van Winkle, Q.; Kraus, K.A.


    A process is presented for separating polonium, protactinium, or mixtures thereof in aqueous solution from bismuth, zirconium, lead, and niobium values contained in the solution. The method comprises providing hydrochloric acid in the solution in a concentration of at least 5N. contacting the aqueous solution with a substantially waterimmiscible organic solvent such as diisopropyl ketone, and separating the aqueous phase containing the bismuth, zirconium, lead, and niobium from the organic extract phase containing the polonium, protactinium, or mixture thereof.

  5. Simple and scalable iodination of 2,6–dialkylanilines: useful building blocks for synthesis.



    Authors: Houssein Ibrahim, Clémentine Gibard, Audrey Hospital, Christelle Gaulier, Natasha Hewitt, Arnaud Gautier & Federico Cisnetti ### Abstract The syntesis of 2,6-dimethyl-4-iodoaniline and 2,6-diisopropyl-4-iodoanilne is described. Both compounds were easily obtained in using an aromatic iodination reaction with molecular iodine. The desired products were isolated in nearly quantitative yields after a simple extraction. The crude materials are pure according to NMR. ###...

  6. Experimental and clinical trials of new /sub 99m/Tc-labeled hepatobiliary agents. [Iminodiacetic acid derivatives

    Wistow, B.W.; Subramanian, G.; Gagne, G.M.; Henderson, R.W.; McAfee, J.G.; Hall, R.C.; Grossman, Z.D.


    Several new derivatives of lidocaine were synthesized and used to examine the intra- and extrahepatic bile ducts and gallbladder. Diisopropyl-IDA exhibited approximately twice the bile concentration of /sup 131/I-rose bengal during the first hour after injection. P-butyl-IDA also concentrates moderately well in the bile and has the added advantage of very low excretion into the urine (2%). It seems more effective than the other IDA derivatives at high bilirubin levels.

  7. Desenvolvimento de sistemas líquido-cristalinos empregando silicone fluido de co-polímero glicol e poliéter funcional siloxano Development of liquid-crystalline systems using silicon glycol copolymer and polyether functional siloxane

    Marlus Chorilli


    Full Text Available For the construction of the phase diagrams, the method of the aqueous titration was used. There were prepared 5 ternary diagrams, varying the surfactant and the oil phase. The liquid-crystalline phases were identified by polarized light microscopy. The formulations prepared with silicon glycol copolymer, polyether functional siloxane (PFS and water (S1 and with diisopropyl adipate, PFS and water (S4 presented liquid-crystalline phases with lamellar arrangement. Moreover, after 15 days in hot oven (37 ºC, the formulations presented hexagonal arrangement, evidencing the influence of the temperature in the organization of the system.

  8. Monomeric 55-kDa guanidinobenzoatase switches to a serine proteinase activity upon tetramerization. Tetrameric proteinase SP 220 K appears as the native form.

    Poustis-Delpont, C; Thaon, S; Auberger, P; Gerardi-Laffin, C; Sudaka, P; Rossi, B


    Guanidinobenzoatases are cell surface enzymes present in cells capable of migration or remodeling. The guanidinobenzoatase purified to homogeneity from human renal carcinoma did not display gelatinase activity under the 55-kDa form (Poustis-Delpont, C., Descomps, R., Auberger, P., Delque-Bayer, P., Sudaka, P., and Rossi, B. (1992) Cancer Res. 52, 3622-3628). We bring new insights into the structure-activity relationships of this enzyme using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, [3H]diisopropyl fluorophosphate labeling, gelatin zymography, and immunodetection using a polyclonal antibody raised against the 55-kDa entity. Upon aggregation into a 220-kDa form, the enzyme exhibited [3H]diisopropyl fluorophosphate labeling and diisopropyl fluorophosphate-inhibitable gelatinase activity whereas its capability to cleave p-nitrophenyl p'-guanidinobenzoate as a substrate was abolished. Thus, the guanidinobenzoatase property appears as a feature of a 55-kDa inactive form of a serine proteinase subunit. After boiling in the presence of sodium dodecyl sulfate (3% w/v), the 220-kDa entity subjected to SDS-polyacrylamide gel electrophoresis could be dissociated into a 55-kDa protein as shown by silver staining. The resulting 55-kDa band remained [3H]diisopropyl fluorophosphate-labeled and reacted with anti-55-kDa guanidinobenzoatase antibodies, strongly suggesting that the 220-kDa proteinase was a noncovalently associated tetramer. Interestingly, Triton X-100 extracts of renal carcinoma plasma membranes exhibited a 220-kDa serine proteinase activity, as expressed in gelatin zymography, which was barely detectable in the non-tumoral counterpart. It is noteworthy that an anti-55-kDa guanidinobenzoatase reactive 220-kDa species was also observed in renal carcinoma plasma membranes extracts as assessed by Western blot, whereas it was hardly visible in the non-tumoral counterpart. No signal was immunodetected at M(r) 55,000 in renal carcinoma and kidney cortex

  9. LC-MS analysis of the formed peptides from N-( O, O-diiso-propyl) phosphoryl aspartic acid

    胡建军; 巨勇; 赵玉芬


    IC-ESI-MS method was used to analyze the formed di- and ri- peptide in the reaction system of N-(O, O-diisopropyl) phosphoryl aspartic acid and adenosine. Cluster ions of the peptides were given in the ESI-MS. The structures of these small peptides were confirmed by LC-MS-MS analysis. Compared wih the traditional HPLC-UV detection, this method showed good sensitivity and selectivity for peptide in the presence of compounds with strong UV ahsorption, such as nucleoside and nucleotide.

  10. Purification and some properties of factor D of the human properdin system.

    Dieminger, L; Vogt, W; Lynen, R


    Factor D has been purified by gel and ion exchange chromatographies, and by ultrafiltration through different membranes. The final preparation appeared pure in various analytical tests. The molecular weight of human D is 21,500 according to gel chromatography, the isoelectric point was found at pH 7.8. Factor D is an active esterolytic enzyme, it cleaves N-alpha-acetyl-L-lysine methyl ester and N-alpha-acetyl-L-glycyl-L-lysine methyl ester. Both peptide esters inhibit the hydrolytic activation of factor B by D in the presence of cobra venom factor. D is also inhibited by diisopropyl-fluorophosphate and by penylmethyl-sulfonyl-flouride.

  11. Chromatographic Separation Method for the Simulant Mixture of Triisopropyl Phosphite and Bis(2-Ethylhexyl) Hydrogen Phosphite


    that of diisopropyl hydrogen phosphite (DIP) that could yield an error in the purity results if coelu- tion with TIP occurs. The DIP component is a...source of potential error if it is not completely separated from the TIP. The purpose of this investigation is to perform the initial GC development...8217 Retention Time 2 (min) Area3 1. 2-propanol 1.1 981078 2. TIP 3.44 15685456 3. DIP 5.68 7205570 4. TIPO 1.15 3584104 5. --- 14.63 720318 6. 17.63

  12. Organoberyllium compounds and their chemical reactions. XI. Synthesis of diacetylhydrobenzoins

    Lapkin, I.I.; Sinani, S.V.


    The authors previously determined that the reaction of aromatic aldehydes with acylhaloberyllium in ethyl acetate lead to the formation of stilbene. In this same vein they have found that the final products of this reaction can include not only stilbenes but also diacetylhydrobenzoin and that the product is determined by the nature of the solvent. In this paper they determine that while ethyl acetate indeed leads to the stilbene the use of an ether--diethyl or diisopropyl--leads to diacetylhydrobenzoin. NMR spectroscopy is used to ascertain the structure of the product.

  13. Identification and characterization of dimeric oxidation products of p-cymene-2,3-diol isolated from Thymus vulgaris L.

    Rainis, Guido; Ternes, Waldemar


    The aim of this study was to investigate the oxidation products of p-cymene-2,3-diol, a major antioxidative constituent of thyme (Thymus vulgaris L.). Although a dimeric form of p-cymene-2,3-diol and some derivative substances exhibiting valuable food technological and health-promoting properties have been reported in earlier publications, no obvious correlation has been shown between these substances. A modified HPLC-ESI-MS method made it possible to prove that two dimers, 3,4,3',4'-tetrahydroxy-5,5'-diisopropyl-2,2'-dimethylbiphenyl (1) and the newly identified 3',4'-dihydroxy-5,5'-diisopropyl-2,2'-dimethylbiphenyl-3,4-dione (2), are oxidation products of p-cymene-2,3-diol. 2 was characterized by the fragmentation pattern determined by multiple mass spectrometry, (1)H NMR, (13)C NMR, H-H COSY, HSQC, and HMBC. Both biphenyls were also quantitated in freeze-dried thyme as well as in a food matrix spiked with thyme extract. Model experiments using raw and cooked minced pork meat as matrix and sodium nitrite as oxidizing and reduction agent with and without ascorbic acid as protective reagent showed the correlation between food processing and dimer generation.

  14. OH Production from Reactions of Organic Peroxy Radicals with HO2 : Recent Studies on Ether-Derived Peroxy Radicals

    Orlando, J. J.; Tyndall, G. S.; Kegley Owen, C. S.; Reynoldson, N.


    There is now ample evidence supporting significant formation of OH radicals in the reaction of HO2 with certain organic peroxy radicals (RO2). These reaction channels serve to promote radical propagation, and thus have the potential to alter HOx budgets and partitioning and hence tropospheric oxidative capacity. While much focus has been placed on OH production from reactions involving carbonyl-containing RO2 species, it is also the case that other oxygen- substituted peroxy species (e.g., CH3OCH2OO, HOCH2OO) likely generate OH in their reactions with HO2 (see ref. 1 and refs therein). In this work, the Cl-atom-initiated oxidation of two ethers, diethyl and diisopropyl ether, is investigated over ranges of conditions in an environmental chamber, using both FTIR and GC-FID methods for product quantification. Preliminary analysis suggests that significant OH production is occurring in the reaction of HO2 with CH3CH2OCH(OO)CH3, and also provides evidence for a rapid unimolecular reaction of diisopropyl ether-derived peroxy radicals. Details of these and other results will be described. 1. Orlando, J. J., and G. S. Tyndall, 2012: Laboratory studies of organic peroxy radical chemistry: an overview with emphasis on recent issues of atmospheric significance, Chemical Society Reviews, 41, 6294-6317, doi: 10.1039/C2CS35166H.

  15. Synthesis and characterization of novel triptycene dianhydrides and polyimides of intrinsic microporosity based on 3,3ʹ-dimethylnaphthidine

    Ghanem, Bader


    Two intrinsically microporous polyimides were obtained by high-temperature, one-pot poly-condensation reaction of novel triptycene-based dianhydrides containing dimethyl- or diisopropyl-bridgehead groups with a commercially available highly sterically hindered 3,3 \\'-dimethylnaphthidine (DMN) diamine monomer. The dimethyl bridgehead groups in the triptycene building block provided the DMN-based polyimide (TDA1-DMN) with larger surface area (760 m(2) g(-1)) than the diisopropyl-based polyimide (TDA1-DMN) (680 m(2) g(-1)), greater fraction of ultramicroporosity, as observed from N-2 and CO2 NLDFT adsorption analysis, and higher gas permeability and selectivity. Wide-angle X-ray diffraction (WAXD) measurements demonstrated that TDA1-DMN and TDAi3-DMN exhibited a bimodal pore size distribution, where TDA1-DMN showed smaller d-spacing values and broader intensity peaks. Both TDADMN-based polyimides showed very high gas permeabilities with moderate selectivities. For example, fresh TDA1-DMN exhibited an O-2 permeability of 783 Barrer coupled with an O-2/N-2 selectivity of 4.3 and H-2 permeability of 3050 Barrer with H-2/N-2 selectivity of 16.7, values that surpassed the 2008 Robeson permeability/selectivity upper bounds. Physical aging of the TDA-DMN polyimide films over a period of 250 days showed relatively small changes in permeability (similar to 20%) and selectivity (similar to 5%). (C) 2016 Elsevier Ltd. All rights reserved.

  16. Solvent-assisted stir bar sorptive extraction by using swollen polydimethylsiloxane for enhanced recovery of polar solutes in aqueous samples: Application to aroma compounds in beer and pesticides in wine.

    Ochiai, Nobuo; Sasamoto, Kikuo; David, Frank; Sandra, Pat


    A novel solvent-assisted stir bar sorptive extraction (SA-SBSE) technique was developed for enhanced recovery of polar solutes in aqueous samples. A conventional PDMS stir bar was swollen in several solvents with log Kow ranging from 1.0 to 3.5 while stirring for 30min prior to extraction. After extraction, thermal desorption - gas chromatography - (tandem) mass spectrometry (TD-GC-(MS/)MS) or liquid desorption - large volume injection (LD-LVI)-GC-MS were performed. An initial study involved investigation of potential solvents for SA-SBSE by weighing of the residual solvent in the swollen PDMS stir bar before and after extraction. Compared to conventional SBSE, SA-SBSE using diethyl ether, methyl isobutyl ketone, dichloromethane, diisopropyl ether and toluene provided higher recoveries from water samples for test solutes with log Kow2.5. The performance of the SA-SBSE method using dichloromethane, diisopropyl ether, and cyclohexane is illustrated with analyses of aroma compounds in beer and of pesticides in wine. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  17. N-heterocyclic carbene-induced zwitterionic ring-opening polymerization of ethylene oxide and direct synthesis of alpha,omega-difunctionalized poly(ethylene oxide)s and poly(ethylene oxide)-b-poly(epsilon-caprolactone) block copolymers.

    Raynaud, Jean; Absalon, Christelle; Gnanou, Yves; Taton, Daniel


    An N-heterocyclic carbene (NHC), namely, 1,3-bis-(diisopropyl)imidazol-2-ylidene (1), was demonstrated to bring about the metal-free ring-opening polymerization of ethylene oxide at 50 degrees C in dimethyl sulfoxide, in absence of any other reagents. Poly(ethylene oxide) (PEO) of polydispersities ethylene oxide to form a zwitterionic species, namely 1,3-bis-(diisopropyl)imidazol-2-ylidinium alkoxide, that further propagates by a zwitterionic ring-opening polymerization (ZROP) mechanism. Through an appropriate choice of terminating agent NuH or NuSiMe(3) at the completion of the polymerization, a variety of end-functionalized PEO chains could be generated. In particular, alpha,omega-bis(hydroxy)-telechelic PEO, alpha-benzyl,omega-hydroxy, and alpha-azido,omega-hydroxy-difunctionalized PEOs were synthesized by NHC (1)-initiated ZROP, using H(2)O, PhCH(2)OH, and N(3)SiMe(3) as terminating agent, respectively. Characterization of these alpha,omega-difunctionalized PEOs by techniques such as (1)H NMR spectroscopy, MALDI-TOF spectrometry, and size exclusion chromatography confirmed the quantitative introduction of functional groups at both alpha and omega positions of the PEO chains and the formation of very narrow molar mass polymers. Finally, the synthesis of a poly(ethylene oxide)-b-poly(epsilon-caprolactone) diblock copolymer by sequential ZROP of the corresponding monomers was successfully achieved using (1) as organic initiator without isolation of the PEO block intermediate.

  18. Potentiating action of propofol at GABAA receptors of retinal bipolar cells

    Yue, Lan; Xie, An; Bruzik, Karol S


    Purpose. Propofol (2,6-diisopropyl phenol), a widely used systemic anesthetic, is known to potentiate GABA(A) receptor activity in a number of CNS neurons and to produce changes in electroretinographically recorded responses of the retina. However, little is known about propofol's effects...... on specific retinal neurons. The authors investigated the action of propofol on GABA-elicited membrane current responses of retinal bipolar cells, which have both GABA(A) and GABA(C) receptors. Methods. Single, enzymatically dissociated bipolar cells obtained from rat retina were treated with propofol...... delivered by brief application in combination with GABA or other pharmacologic agents or as a component of the superfusing medium. Results. When applied with GABA at subsaturating concentrations and with TPMPA (a known GABA(C) antagonist), propofol markedly increased the peak amplitude and altered...

  19. Terminal group effects on the fluorescence spectra of europium(III) nitrate complexes with a family of amide-based 2,3-dihydroxynaphthalene derivatives

    Lei, Ke-Wei; Liu, Wei-Sheng


    Three ligands 2,2'-[2,3-naphthylenebis(oxy)]-bis( N, N-diethyl(acetamide)) (L a), 2,2'-[2,3-naphthylenebis(oxy)]-bis( N, N-diisopropyl(acetamide)) (L b) and 2,2'-[2,3-naphthylenebis(oxy)]-bis( N, N-dibutyl(acetamide)) (L c) and their europium(III) nitrate complexes were synthesized. The complexes were characterized by elemental analysis, IR, fluorescence spectroscopy and conductivity. The europium atoms are coordinated by O-atoms from C dbnd O, Ar-O-C. With the difference of the ligands, the solid fluorescent intensities of the Eu complexes vary regularly. Some factors that influencing the fluorescent intensity were discussed.

  20. Determination of small dialkyl organophosphonates at microgram/l concentrations in contaminated groundwaters using multiple extraction membrane disks

    Tomkins, B.A.; Griest, W.H. [Oak Ridge National Lab., TN (United States); Hearle, D.R. [Parkdale High School, Riverdale, MD (United States)


    Di-isopropyl methylphosphonate (DIMP) and dimethyl methylphosphonate (DMMP) are byproducts and surrogates for Sarin (GB) and VX; they are readily quantitated at {mu}g/L concentrations in groundwaters. Liter aqueous samples are fortified with triethylphosphate, then passed through a sandwich of 3 preconditioned extraction disks: glass fiber filter to remove particulates, C{sub 18}-based extraction disk to collect DIMP, and carbon-based extraction disk to collect DMMP. The two extraction disks are dried and extracted with MeOH. After the extract is fortified with with diethyl ethylphosphonate internal standard, it is analyzed using a gas chromatograph with a nitrogen- phosphorus detector. When the pump and treat criterion is used, detection limits for DMMP and DIMP are 2 {mu}g/L. Method recovery is 40-50%, based on synthetic groundwaters containing 0.2-50 {mu}g/L of each analyte. DIMP and DMMP are cleanly resolved.

  1. Copolymerization of Ethylene and Vinyl Amino Acidic Ester Catalyzed by Titanium and Zirconium Complexes

    Jing Wang


    Full Text Available A series of titanium and zirconium complexes with ligands based on di-isopropyl phosphorus-phenylamine and their derivatives were synthesized and characterized. These catalysts were utilized to catalyze the copolymerization of ethylene with N-acetyl-O-(dec-9-enyl-L-tyrosine ethyl ester with high catalytic activity of 6.63 × 104 g P (mol Ti−1 h−1 after activation by methylaluminoxane (MAO. The effects of ligand structure, metal atoms (Ti, Zr and polymerization conditions were investigated in detail. The obtained polymers were characterized by 13C-NMR, DSC, FT-IR, and GPC. The results showed that the obtained copolymer had a high comonomer incorporation rate of 2.56 mol % within the copolymer chain. The melting temperature of the copolymer was up to 138.9 °C, higher than that of the obtained homopolyethylene.

  2. A butyrylcholinesterase in the early development of the brine shrimp (Artemia salina) larvae: a target for phthalate ester embryotoxicity?

    Acey, Roger A; Bailey, Stacie; Healy, Patricia; Jo, Chang; Unger, Thomas F; Hudson, Richard A


    The phthalate ester insensitive blue-green algae (Synechococcus lividus) were used as a food source to extend the survival of synchronously hatched brine shrimp (Artemia salina) larvae allowing measurement of a reduced toxic response to phthalate esters at late post-hatching stages of development. The maximum acute toxicity due to di-n-butyl phthalate (DNBP) correlated with the expression of a phthalate ester-hydrolyzing enzyme. The purified enzyme was identified as a butyrylcholinesterase due to its rapid inactivation by low concentrations (10(-7)M) of diisopropyl fluorophosphate and inhibition by physostigmine (IC(50)=6 x 10(-7)M) and tetraisopropylpyrophosphoramide (I-OMPA, IC(50)=x 10(-6)M) but not by BW284c5. Apparently competition of the phthalates with the endogenous substrates of the enzyme led to development-dependent toxicity.




    针对鲁奇气化炉气化废水的特点,通过对二异丙基醚、甲基异丁基酮和醋酸丁酯等萃取剂的物理性质、脱酚效果和COD脱除效果的比较,选择出一种对鲁奇气化炉气化废水最有效的脱酚萃取剂。%With the features of gasification waste water from Lurgi gasifier and the comparison in aspects of physical property,dephenolization and COD-removal effects of the extractants as diisopropyl ether,MIBK and acetic butyl ester,a dephenolization extractant most effective to the gasification waste water from Lurgi gasifier is selected.

  4. Anti-enterovirus 71 effects of chrysin and its phosphate ester.

    Jianmin Wang

    Full Text Available Enterovirus 71 (EV71 can cause severe disease and even lead to death in children, and an effective antiviral drug is currently unavailable. The anti-EV71 effect of chrysin (5,7-dihydroxyflavone, a natural flavonoid commonly found in many plants, was tested in this report. By using the predicting program Autodock 4.0 and an in vitro protease inhibition assay, we found that chrysin could suppress viral 3Cpro activity. Replication of viral RNA and production of viral capsid protein and the infectious virion were strongly inhibited by chrysin, without noticeable cytotoxicity. Cytopathic effects on cells were also prevented. Diisopropyl chrysin-7-yl phosphate (CPI, the phosphate ester for chrysin, was generated through a simplified Atheron-Todd reaction to achieve stronger anti-viral activity. CPI was also able to bind with and inhibit viral 3Cpro activity in vitro. As expected, CPI demonstrated more potent antiviral activity against EV71.

  5. An efficient protocol for the palladium-catalysed Suzuki-Miyaura cross-coupling

    Marziale, Alexander N.


    The palladacyclic catalyst precursor received by ortho-palladation of ([1,1′-biphenyl]-2-yloxy)diisopropyl-phosphine represents a highly active system for Suzuki-Miyaura cross-coupling reactions when used in neat water. An efficient, broadly applicable and sustainable aqueous protocol was developed using 2.5 eq. of Na2CO3 as base, allowing the reaction to be performed under air and at ambient temperature with Pd loadings of 0.04 mol%. Coupling products are obtained in high yields and excellent purity by simple filtration with no organic solvents needed throughout the whole reaction. A broad variety of functional groups are tolerated and a large number of substrates can be applied with this protocol. The crystal structure of the palladacyclic catalyst precursor is presented as well as investigations targeting the nature of catalyst activation and the active catalytic species. © 2011 The Royal Society of Chemistry.

  6. An extraovarian protein accumulated in mosquito oocytes is a carboxypeptidase activated in embryos

    Wenlong Cho; Deitsch, K.W.; Raikhel, A.S. (Michigan State Univ., East Lansing (United States))


    The authors report a phenomenon previously unknown for oviparous animals; in Aedes aegypti mosquitoes a serine carboxypeptidase is synthesized extraovarially and then internalized by oocytes. The cDNA encoding mosquito vitellogenic carboxypeptidase (VCP) was cloned and sequenced. The VCP cDNA hybridizes to a 1.5-kilobase mRNA present only in the fat body of vitellogenic females. The deduced amino acid sequence of VCP shares significant homology with members of the serine carboxypeptidase family. Binding assays using a serine protease inhibitor, ({sup 3}H)diisopropyl fluorophosphate, showed that VCP is activated in eggs at the onset of embryonic development. Activation of VCP is associated with the reduction in its size from 53 kDa (inactive proenzyme) to 48 kDa (active enzyme). The active, 48-kDa, form of VCP is maximally present at the middle of embryonic development and disappears by the end.

  7. Correlation between fluidising effects on phospholipid membranes and mitochondrial respiration of propofol and p-nitrosophenol homologues.

    Momo, Federico; Fabris, Sabrina; Wisniewska, Anna; Fiore, Cristina; Bindoli, Alberto; Scutari, Guido; Stevanato, Roberto


    Nitrosopropofol (2-6-diisopropyl-4-nitrosophenol) has dramatic consequences for respiration, ATP synthesis and the transmembrane potential of isolated rat liver mitochondria at concentrations at which propofol (2-6-diisopropylphenol) does not cause any apparent effects. These results correlate well with the observation that nitrosopropofol is also a stronger perturbing agent of phospholipid membranes. In this paper we verify the possible biological activity of different phenols and nitrosophenols on mitochondrial respiration. We then discuss their interactions with phospholipid liposomes, studied with differential scanning calorimetry, spin labelling techniques and UV-Vis spectrophotometry, in order to obtain information on drug distribution and the modifications they impose on lipid bilayer. The results of the experiments performed on mitochondria and model membranes prove an interesting correlation between the effects of the molecules on both systems.

  8. cDNA cloning of porcine brain prolyl endopeptidase and identification of the active-site seryl residue

    Rennex, D.; Hemmings, B.A.; Hofsteenge, J.; Stone, S.R. (Friedrich Miescher-Institut, Basel (Switzerland))


    Prolyl endopeptidase is a cytoplasmic serine protease. The enzyme was purified from porcine kidney, and oligonucleotides based on peptide sequences from this protein were used to isolate a cDNA clone from a porcine brain library. This clone contained the complete coding sequence of prolyl endopeptidase and encoded a polypeptide with a molecular mass of 80751 Da. The deduced amino acid sequence of prolyl endopeptidase showed no sequence homology with other known serine proteases. ({sup 3}H)Diisopropyl fluorophosphate was used to identify the active-site serine of prolyl endopeptidase. One labeled peptide was isolated and sequenced. The sequence surrounding the active-site serine was Asn-Gly-Gly-Ser-Asn-Gly-Gly. This sequence is different from the active-site sequences of other known serine proteases. This difference and the lack of overall homology with the known families of serine proteases suggest that prolyl endopeptidase represents a new type of serine protease.

  9. Health assessment of gasoline and fuel oxygenate vapors: developmental toxicity in rats.

    Roberts, Linda G; Gray, Thomas M; Trimmer, Gary W; Parker, Robert M; Murray, F Jay; Schreiner, Ceinwen A; Clark, Charles R


    Gasoline-vapor condensate (BGVC) or condensed vapors from gasoline blended with methyl t-butyl ether (G/MTBE), ethyl t-butyl ether (G/ETBE), t-amyl methyl ether (G/TAME) diisopropyl ether (G/DIPE), ethanol (G/EtOH), or t-butyl alcohol (G/TBA) were evaluated for developmental toxicity in Sprague-Dawley rats exposed via inhalation on gestation days (GD) 5-20 for 6h/day at levels of 0 (control filtered air), 2000, 10,000, and 20,000mg/m(3). These exposure durations and levels substantially exceed typical consumer exposure during refueling (gasoline and gasoline blended with the ether or alcohol oxygenates.

  10. Bis[μ-N,N′-bis(2,6-diisopropylphenyl)ethene-1,2-diamido]-1,4(η2);1:2κ4 N:N;3:4κ4 N:N-bis(diethyl ether)-1κO,4κO-di-μ-hydrido-2:3κ4 H:H-2,3-dichromium(II)-1,4-dilithium(I) pentane hemisolvate

    Peitz, Stephan; Peulecke, Normen; Müller, Bernd H.; Spannenberg, Anke; Rosenthal, Uwe


    The title compound, [Cr2Li2(C26H36N2)2(μ-H)2(C4H10O)2]·0.5C5H12, is a binuclear chromium complex bridged by two hydrogen atoms. Each chromium atom is coordinated in a distorted square-planar geometry by one chelating bis­(2,6-diisopropyl­phen­yl)ethene-1,2-diamido ligand via its two N atoms. Additionally, two diametrically opposed lithium ether adducts coordinate in an η4 mode on the backbone of the ligands. There is a crystallographic inversion center in the middle of the Cr2H2 ring. One of the isopropyl groups is disordered over two positions in a 0.567 (7):0.433 (7) ratio. Disorder is also observed in the pentane hemisolvate molecule. PMID:21580241

  11. Synthesis of highly reactive polyisobutylene with FeCl3/ether complexes in hexane; kinetic and mechanistic studies

    Kumar, Rajeev Ananda


    The kinetics and mechanism of the polymerization of isobutylene catalyzed by FeCl3·ether complexes in hexane at 0°C were investigated. The polymerization rates increased in the diisopropyl ether< 2-chloroethyl ethyl ether < bis(2-chloroethyl) ether order, attributed to electronic effects. The polymerization rates increased with increasing initiator and catalyst concentrations. The first order plots, however, deviated from the linear suggesting that the cation concentration decreases with time. The previously proposed mechanism is inadequate to explain this finding. The decrease in the polymerization rate with time is explained by the low solubility of the H+ROR′FeCl4 - complexes that precipitate during polymerization. Based on mechanistic studies the revised mechanism now also includes the equilibrium H+ROR′FeCl4 - ⇋ HCl + FeCl3·ROR′.

  12. Activation of pro-urokinase and plasminogen on human sarcoma cells

    Stephens, R. W.; Pöllänen, J.; Tapiovaara,, Hannele


    Human HT-1080 fibrosarcoma cells produce urokinase-type plasminogen activator (u-PA) and type 1 plasminogen activator inhibitor (PAI-1). We found that after incubation of monolayer cultures with purified native human plasminogen in serum-containing medium, bound plasmin activity could be eluted...... from the cells with tranexamic acid, an analogue of lysine. The bound plasmin was the result of plasminogen activation on the cell surface; plasmin activity was not taken up onto cells after deliberate addition of plasmin to the serum-containing medium. The cell surface plasmin formation was inhibited...... by an anticatalytic monoclonal antibody to u-PA, indicating that this enzyme was responsible for the activation. Preincubation of the cells with diisopropyl fluorophosphate-inhibited u-PA led to a decrease in surface-bound plasmin, indicating that a large part, if not all, of the cell surface plasminogen activation...

  13. Enzymatic Enantioselective Synthesis of (R)-2-Trimethylsilyl-2-hydroxyl-propionitrile by Defatted Apple Seed Meal

    LI, Ning; ZONG,Min-Hua; WANG, Ju-Fang; LIU, Chen; WU, Hong


    The enantioselective synthesis of (R)-2-trimethylsilyl-2-hydroxyl-propionitrile by ( R )-oxynitrilase contained in defatted apple seed meal in a biphasic system was successfully performed. The influences of some factors on the reaction were investigated systematically. Diisopropyl ether was found to be the best for this reaction among all the organic solvents examined. The optimal concentration of defatted apple seed meal, aqueous phase content, concentrations of acetyltrimethylsilane and acetone cyanohydrin, buffer pH, reaction temperature were 4% (W/V),23% (V/V), 20 mmol.L-1, 40 mmol.L-1, pH=5.0 and 40 ℃, respectively, under which the initial reaction rate, substrate conversion and product enantiomeric excess were 9.4mmol.L-1·h-1, 99% and > 99%, respectively.

  14. Interactions of phosphororganic agents with water and components of polyelectrolyte membranes.

    Lee, Ming-Tsung; Vishnyakov, Aleksey; Gor, Gennady Yu; Neimark, Alexander V


    Interactions of nerve G-agents (sarin and soman) and their simulants DMMP (dimethyl methylphosphonate) and DIFP (diisopropyl fluorophosphate) with water and components of polyelectrolyte membranes are studied using ab initio calculations in conjunction with thermodynamic modeling using the conductor-like screening model for real solvents (COSMO-RS). To test reliability of COSMO-RS calculations, we measured the vapor-liquid equilibrium in DMMP-water mixtures and found quantitative agreement between computed and experimental results. Using COSMO-RS, we studied the interactions of phosphororganic agents with the characteristic fragments of perfluorinated and sulfonated polystyrene (sPS) polyelectrolytes, which are explored for protective clothing membranes. We found that both simulants, DIFP and DMMP, mimic the thermodynamic properties of G-agents reasonably well; however, there are certain specific differences that are discussed. We also suggested that sPS-based polyelectrolytes have less affinity for phosphorganic agents compared to prefluorinated polyelectrolytes similar to Nafion.

  15. Acetalization of carbonyl compounds with 2,2,4-trimethyl-1,3-pentanedio catalyzed by novel carbon based solid acid catalyst

    Ling Liu; Yuechang Zhao; Shan Gan; Xuezheng Liang; Jianguo Yang; Mingyuan He


    The synthesis of 2, 4-diisopropyl-5,5-dimethyl-1,3-dioxane through the acetalization of isobutyraldehyde with 2, 2,4-trimethyl-1,3-pentanediol (TMPD) catalyzed by the novel carbon based acid was first carried out. High conversion (≥98%) and specific selectivity were obtained using the novel carbon based acid, which kept high activity after it was reused 5 times.Moreover, the catalyst could be used to catalyze the acetalization and ketalization of different aldehydes and ketones with superior yield. The yield of several products was over 90%. The novel heterogeneous catalyst has the distinct advantages of high activity, strikingly simple workup procedure, non-pollution, and reusability, which will contribute to the success of the green process greatly.

  16. Method for determination of uranium isotopes in environmental samples by liquid-liquid extraction with triisooctylamine/xylene in hydrochloric media and alpha spectrometry.

    Popov, L


    Alternative method for determination of uranium isotopes in various environmental samples is presented. The method is based on total decomposition of the solid materials and preconcentration of liquid samples. The separation of uranium from interfering radionuclides and stable matrix elements is attained by liquid-liquid extraction with triisooctylamine/xylene in hydrochloric media. After the additional removal of stable iron by extraction with diisopropyl ether, purified uranium is electrodeposited on stainless steel disks and measured by alpha spectrometry. The analytical method has been successfully applied to the determination of uranium isotopes in water and bottom sediments from the rivers Danube, Ogosta and Tzibritza in Northwestern Bulgaria. The analytical quality was checked by analyzing reference materials with different matrices.

  17. Autocatalysis in lithium diisopropylamide-mediated ortholithiations.

    Singh, Kanwal J; Hoepker, Alexander C; Collum, David B


    Ortholithiation of 3-fluorophenyl-N,N-diisopropyl carbamate by lithium diisopropylamide (LDA) in THF at -78 degrees C affords unusual rate behavior including linear decays of the carbamate, delayed formation of LDA-aryllithium mixed dimers, and evidence of autocatalysis. A mechanistic model in conjunction with numeric integration methods accounts for the time-dependent changes in concentration. The two critical rate-limiting steps in the model entail (1) an LDA dimer-based metalation of arylcarbamate, and (2) a rate-limiting condensation of the resulting aryllithium with the LDA dimer to form two isomeric LDA-ArLi mixed dimers. One isomer elicits a highly efficient (post-rate-limiting) metalation of aryl carbamate, in turn, regenerating aryllithium. The prevalence and implications of such autocatalysis are discussed.

  18. 信息动态%Polymerization of 1-butene with spherical MgCI2-supported catalyst


    The activity of the spherical MgCl2-supported catalyst for 1-butene polymerization reached 607 g/g and the isotacticity index of poly(l-butene) prepared with the catalyst attained 82.3% under the following optimal conditions: triethyl aluminum as cocatalyst, molar ratio of Al to Ti 300, polymerization pressure 0.10 MPa, polymerization temperature 30 ℃, hydrogen 3 mL, molar ratio of cyclohexyl methyl dimethoxy s/lane (CHMMS) to Al 0.033 and reaction time 2 hr. The ranking of external electron donors could be expressed in descending order on the basis of either the catalyst activity as CHMMS, dieyclopentyl dimethoxy silane(DCPMS), diisobutyl dimethoxy silane(DIBMS), diisopropyl dimethoxy silane(DIPMS) and diphenyl dimethoxy silane(DDS), or the isotacticity index of poly(l-butene) as DCPMS, DIPMS, DIBMS, CHMMS and DDS.

  19. Solid state polymerization and crystallography of polyimide precursors. Ph.D. Thesis - Va. Univ.

    Wakelyn, N. T.


    Although the production of crystallinity in a polymeric system has historically led to commerically useful properties, the polyimides, prized for their high temperature characteristics, as customarily synthesized by melt or solution casting, are amorphous. It is shown that polymide containing residual crystallinity can be synthesized by isothermal annealing of crystals of the salt of the diisopropyl ester of pyromellitic acid and phenylene diamine. The reaction is topochemical in that the geometry of the polymer product is dependent upon that of the crystalline precursor. Infrared spectroscopy reveals the presence of imide absorption in the polymer, while powder diffractometry suggests residual crystallinity. Single crystal X-ray analysis of the monomer yields a structure of chains of alternating acid and base suggesting that the monomer is amenable to polymerization with a minimum of geometrical disruption.

  20. Identification of alkylated phosphates by gas chromatography-mass spectrometric investigations with different ionization principles of a thermally aged commercial lithium ion battery electrolyte.

    Weber, Waldemar; Kraft, Vadim; Grützke, Martin; Wagner, Ralf; Winter, Martin; Nowak, Sascha


    The thermal aging process of a commercial LiPF6 based lithium ion battery electrolyte has been investigated in view of the formation of volatile phosphorus-containing degradation products. Aging products were analyzed by GC-MS. Structure determination of the products was performed by support of chemical ionization MS in positive and negative modes. A fraction of the discovered compounds belongs to the group of fluorophosphates (phosphorofluoridates) which are in suspect of potential toxicity. This is well known for relative derivatives, e.g. diisopropyl fluorophosphate. Another fraction of the identified compounds belongs to the group of trialkyl phosphates. These compounds may provide a positive impact on the thermal and electrochemical performance of Li-based batteries as repeatedly described in the literature.

  1. Unusual products in the reactions of phosphorus(III) compounds with N=N, C≡C or conjugated double-bonded systems

    K C Kumara Swamy; E Balaraman; K Praveen Kumar; N Satish Kumar


    The diversity of products in the reaction of diethyl azodicarboxylate (DEAD)/diisopropyl azodicarboxylate (DIAD) and activated acetylenes with PIII compounds bearing oxygen or nitrogen substituents is discussed. New findings that are useful in understanding the nature of intermediates involved in the Mitsunobu reaction are highlighted. X-ray structures of two new compounds (2--Bu-4-MeC6H3O)P (-N--Bu)2P+[(NH--Bu){N[(CO2--Pr)(HNCO2--Pr)]}](Cl-)(2--Bu-4-MeC6H3OH) (23) and [CH2(6--Bu-4-Me-C6H2O)2P(O)C(CO2Me)C-(CO2Me)CClNC(O)Cl] (33) are also reported. The structure of 23 is close to one of the intermediates proposed in the Mitsunobu reaction.

  2. Synthesis of highly reactive polyisobutylene catalyzed by EtAlCl 2/Bis(2-chloroethyl) ether soluble complex in hexanes

    Kumar, Rajeev Ananda


    The polymerization of isobutylene (IB) to yield highly reactive polyisobutylene (HR PIB) with high exo-olefin content using GaCl3 or FeCl3·diisopropyl ether complexes has been previously reported.1 In an effort to further improve polymerization rates and exo-olefin content, we have studied ethylaluminum dichloride (EADC) complexes with diisopropyl ether, 2-chloroethyl ethyl ether (CEEE), and bis(2-chloroethyl) ether (CEE) as catalysts in conjunction with tert-butyl chloride as initiator in hexanes at different temperatures. All three complexes were readily soluble in hexanes. Polymerization, however, was only observed with CEE. At 0 °C polymerization was complete in 5 min at [t-BuCl] = [EADC·CEE] = 10 mM and resulted in PIB with ∼70% exo-olefin content. Studies on complexation using ATR FTIR and 1H NMR spectroscopy revealed that at 1:1 stoichiometry a small amount of EADC remains uncomplexed. By employing an excess of CEE, exo-olefin contents increased up to 90%, while polymerization rates decreased only slightly. With decreasing temperature, polymerization rates decreased while molecular weights as well as exo-olefin contents increased, suggesting that isomerization has a higher activation energy than β-proton abstraction. Density functional theory (DFT) studies on the Lewis acid·ether binding energies indicated a trend consistent with the polymerization results. The polymerization mechanism proposed previously for Lewis acid·ether complexes1 adequately explains all the findings. © 2014 American Chemical Society.

  3. Reduction of the Work Function of Gold by N-Heterocyclic Carbenes

    Kim, Hye Kyung


    N-Heterocyclic carbenes (NHCs) bind strongly to gold and other metals. This work experimentally probes the effect of NHCs on the work function (WF) of gold for the first time, theoretically analyzes the origin of this effect, and examines the effectiveness of NHC-modified gold as an electron-injecting electrode. UV photoelectron spectroscopy shows the WF of planar gold is reduced by nearly 2 eV to values of 3.3–3.5 eV. This effect is seen for NHCs with various heterocyclic cores, and with either small or large N,N′-substituents. DFT calculations indicate the WF reduction results from both the interface dipole formed between the NHC and the gold and from the NHC molecular dipole. For N,N′-diisopropyl-NHCs, an important contributor to the former is charge transfer associated with coordination of the carbene carbon atom to gold. In contrast, the carbene carbon of N,N′-2,6-diisopropylphenyl-NHCs is not covalently bound to gold, resulting in a lower interface dipole; however, a larger molecular dipole partially compensates for this. Single-layer C60 diodes with NHC-modified gold as the bottom electrode demonstrate high rectification ratios and show that these electrodes can act as effective electron-injecting contacts, suggesting they may be useful for a variety of materials applications.

  4. Palladium(ii-Acetylacetonato Complexes with Mesoionic Carbenes: Synthesis, Structures and Their Application in the Suzuki-Miyaura Cross Coupling Reaction

    Lara Hettmanczyk


    Full Text Available A series of novel palladium(ii acetylacetonato complexes bearing mesoionic carbenes (MICs have been synthesized and characterized. The synthesis of the complexes of type (MICPd(acacI (MIC = 1-mesityl-3-methyl-4-phenyl-1,2,3-triazol-5-ylidene (1, 1,4-(2,4,6-methyl-phenyl-3-methyl-1,2,3-triazol-5-ylidene (2, 1,4-(2,6-diisopropyl-phenyl-3-methyl-1,2,3-triazol-5-ylidene (3; acac = acetylacetonato via direct metalation starting from the corresponding triazolium iodides and palladium(ii acetylacetonate is described herein. All complexes were characterized by 1H- and 13C-NMR spectroscopy and high resolution mass spectrometry. Additionally, two of the complexes were characterized by single crystal X-ray crystallography confirming a square-planar coordination geometry of the palladium(ii center. A delocalized bonding situation was observed within the triazolylidene rings as well as for the acac ligand respectively. Complex 2 was found to be an efficient pre-catalyst for the Suzuki-Miyaura cross coupling reaction between aryl-bromides or -chlorides with phenylboronic acid.

  5. Alkylation reaction by the 2-chloropropane of benzene on the hyper saline element processes alumina catalyst; Koenso shori arumina shokubaijo deno benzen no 2-kuroropuropan ni yoru arukiruka hanno

    Imanishi, Kazuhiro; Saeki, Takayuki; Sawada, Tetsuro; Shobu, Akinori


    The semibatch reactor was used at atmospheric pressure, 273K in respect of isopropyl reaction by 2-chloropropane (2CP) of benzene on aluminia catalyst (AmLSA) chlorinated in the high temperature. The AmLSA catalyst showed the activity, which was higher than the AlCl{sub 3} catalyst. Main products were isopropyl benzene (IPB) and para - diisopropyl benzene (dj-IPB) - 1,3,5-triisopropyl benzene (tri-IPB) and, and the generation of 4 substitutes was as a trace. Product composition at 2CP 100% conversion ratio is IPB 76%, di-IPB I9%, tri-IPB 5% Di-IPB in the isopropyl reaction of IPB be 82%, tri-IPB It was 18%. The catalyst was perfectly toxified, even if it is deaerated at the temperature of pyridine adsorption post 573K or less, and it began to recover in the de-aeration of 673K, and it recovered after the de-aeration at 873K to active 43% before the toxification. It was concluded, when the reaction perfectly stops, when the catalyst is removed from system of reaction, and when the elution of the active species has not been generated. In comparison with the result of result of the superscription and alkylation reaction by 1 - chloropropane (ICP) and isopropyl reaction by the aluminum chloride catalyst, the reaction on the AmLSA catalyst was explained with that it progressed by the mechanism of the Friedel-Crafts type. (translated by NEDO)

  6. Alkylation reaction by propene of benzene on the high-temperature chlorination alumina catalyst; Koonensoshori arumina shokubaijo deno benzen no puropen nioru arukiruka hanno

    Imanishi, Kazuhiro; Inui, Kanichiro; Honda, Kazuki; Shobu, Akinori


    Alkylation reaction by propene of benzene on alumina catalyst (AmLSA) chlorinated at 1073K was carried out using semibatch reactor (liquid phase catalytic reaction) and fixed bed flow reactor (vapor phase catalytic reaction) at atmospheric pressure 303K and 303-623K respectively. Products in liquid phase catalytic reaction were isopropyl benzene (IPB), diisopropyl benzene (di-IPB), triisopropyl benzene (tri-IPB), and the dissolution of the catalytic activity kind to the organic solvent was not observed. It was estimated, when propene was made to adsorb on Am LSA, because the generation of isopropylidene and 2 - propylene cation which coordinated in a strong Lewis acid point was observed, isopropyl reaction these cation benzene - complex. The generation of the high order substitute was promoted, when sodium was added to the catalyst, and the meta/para ratio of di-IPB increased. In vapor phase catalytic reaction, tetraisopropyl benzene (tetra-IPB) was also formed, and in the temperature of 473K or less, it was promoted further than the case in which the generation of tetra-IPB and di, tri was liquid phase catalytic reaction. IPB selectivity and selectivity of total replacement arthroplasty benzenes of consumed propene standard increased, when benzene/propene ratio in the raw material gas increased. In addition, at all reaction temperatures, the oligomerization of propene was generated, and the deactivation of the catalyst was caused. (translated by NEDO)

  7. Capillary gas chromatographic analysis of nerve agents using large volume injections. Final report

    Deinum, T.; Nieuwenhuy, C.


    The procedure developed at TNO-Prins Maurits Laboratory (TNO-PML) for the verification of intact organophosphorus chemical warfare agents in water samples was improved. The last step in this procedure, the laborious and non-reproducible transfer of an ethyl acetate extract onto a Tenax-adsorption tube followed by thermal desorption of the Tenax-tube, was replaced by large volume injection of the extract onto a capillary gas chromatographic system. The parameters controlling the injection of a large volume of an extract (200 ul) were investigated and optimized. As ethyl acetate caused severe problems, potential new solvents were evaluated. With the improved procedure, the nerve agents sarin, tabun, soman, diisopropyl fluorophosphate (DFP) and VX could be determined in freshly prepared water samples at pg/ml (ppt) levels. The fate of the nerve agents under study in water at two pH`s (4.8 and 6) was investigated. For VX, the pH should be adjusted before extraction. Moreover, it is worthwhile to acidify water samples to diminish hydrolysis.

  8. Some Investigations on Protease Enzyme Production Kinetics Using Bacillus licheniformis BBRC 100053 and Effects of Inhibitors on Protease Activity

    Zahra Ghobadi Nejad


    Full Text Available Due to great commercial application of protease, it is necessary to study kinetic characterization of this enzyme in order to improve design of enzymatic reactors. In this study, mathematical modeling of protease enzyme production kinetics which is derived from Bacillus licheniformis BBRC 100053 was studied (at 37°C, pH 10 after 73 h in stationary phase, and 150 rpm. The aim of the present paper was to determine the best kinetic model and kinetic parameters for production of protease and calculating Ki (inhibition constant of different inhibitors to find the most effective one. The kinetic parameters Km (Michaelis-Menten constant and Vm (maximum rate were calculated 0.626 mM and 0.0523 mM/min. According to the experimental results, using DFP (diisopropyl fluorophosphate and PMSF (phenylmethanesulfonyl fluoride as inhibitors almost 50% of the enzyme activity could be inhibited when their concentrations were 0.525 and 0.541 mM, respectively. Ki for DFP and PMSF were 0.46 and 0.56 mM, respectively. Kinetic analysis showed that the Lineweaver-Burk model was the best fitting model for protease production kinetics DFP was more effective than PMSF and both of them should be covered in the group of noncompetitive inhibitors.

  9. Solvent Extraction of Chemical Attribution Signature Compounds from Painted Wall Board: Final Report

    Wahl, Jon H.; Colburn, Heather A.


    This report summarizes work that developed a robust solvent extraction procedure for recovery of chemical attribution signature (CAS) compound dimethyl methyl phosphonate (DMMP) (as well as diethyl methyl phosphonate (DEMP), diethyl methyl phosphonothioate (DEMPT), and diisopropyl methyl phosphonate (DIMP)) from painted wall board (PWB), which was selected previously as the exposed media by the chemical attribution scientific working group (CASWG). An accelerated solvent extraction approach was examined to determine the most effective method of extraction from PWB. Three different solvent systems were examined, which varied in solvent strength and polarity (i.e., 1:1 dichloromethane : acetone,100% methanol, and 1% isopropanol in pentane) with a 1:1 methylene chloride : acetone mixture having the most robust and consistent extraction for four original target organophosphorus compounds. The optimum extraction solvent was determined based on the extraction efficiency of the target analytes from spiked painted wallboard as determined by gas chromatography x gas chromatography mass spectrometry (GCxGC-MS) analysis of the extract. An average extraction efficiency of approximately 60% was obtained for these four compounds. The extraction approach was further demonstrated by extracting and detecting the chemical impurities present in neat DMMP that was vapor-deposited onto painted wallboard tickets.

  10. Purification and properties of elastolytic enzyme from Flavobacterium immotum.

    Ozaki, H; Shiio, I


    Elastolytic enzyme was purified and crystallized from culture fluid of Flavobacterium immotum No. 9-35. The purified enzyme was homogeneous on polyacrylamide gel electrophoresis. The molecular weight was determined by Sephadex G-100 gel filtration to be 13,000. The isoelectric point was between pH 8.3 and 8.9. The optimum pH of the enzyme was 7.2 for elastolytic activity. The purified enzyme showed not only elastolytic activity, but also non-specific proteolytic activity against various other proteins. Milk-clotting activity was also observed. The enzyme did not act on keratin, collagen, or fourteen amino acid esters, including N-benzoyl-L-alanine methyl ester, N-benzoyl-L-arginine ethyl ester, and N-acetyl-L-tyrosine ethyl ester, which were typical substrates of pancreatic elastase [EC], trypsin [EC], and chymotrypsin [EC], respectively. However, the enzyme selectively hydrolyzed elastin when both elastin and albumin were present in the reaction mixture. The enzyme was inhibited by o-phenanthroline and various heavy metals such as cadmium, lead, zinc, and mercury. Various inhibitors, such as diisopropyl phosphofluoridate, tosyl-L-lysine chloromethyl ketone, tosyl-L-phenylalanine chloromethyl ketone, trypsin inhibitor, iodoacetamide, etc., had no effect on the elastolytic activity.

  11. An eco-friendly and inexpensive solvent for solution processable CuSCN as a hole transporting layer in organic solar cells

    Chaudhary, Neeraj; Chaudhary, Rajiv; Kesari, J. P.; Patra, Asit


    During past few years, significant research on solution-processable deposition of copper(I)thiocyanate (CuSCN) as an efficient hole transporting layer (HTL) for excitonic solar cells have been successfully reported. Surprisingly, till now only two solvents diisopropyl sulfide and diethyl sulfide are known which have been used for CuSCN film deposition as a HTL for device fabrication. Here, we have used eco-friendly and inexpensive solvent dimethyl sulfoxide (DMSO) for solution processed thin film deposition of CuSCN for organic solar cells. The photovoltaic devices were fabricated using two different donor polymers PCDTBT and PTB7 blended with PC71BM as an acceptor material with device structure of ITO/CuSCN/active layer/Al. The power conversion efficiency (PCE) based on CuSCN using DMSO as a deposition solvent have been achieved up to 4.20% and 3.64% respectively, with relative higher fill factor (FF) as compared to previously reported values in literature. The resultant HTLs were characterized by UV-vis-NIR spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM) and atomic force microscope (AFM) for better understanding.

  12. Facile one-pot synthesis of functionalized organophosphonate esters via ketone insertion into bulky arylphosphites

    Ramaswamy Murugavel; Subramaniam Kuppuswamy


    The reaction of phosphorus trichloride with 2,6-diisopropyl phenol in the presence of LiCl under reflux conditions for 24 h produces a mixture of (ArO)PCl2 and (ArO)2PCl (Ar = 2,6-Pr2C6H3). The hydrolysis of the aryloxy compounds in acetone/H2O results in the formation of two novel phosphonate ester derivatives [(ArO)P(O)(OH)(CMe2OH)] (1) and [(ArO)2P(O)(CMe2OH)] (2), respectively in a moderate yield. The title compounds have presumably formed via acetone insertion to the P-H bonds of (ArO)P(O)(H)(OH) and (ArO)2P(O)(H), respectively, in the presence of HCl produced during the hydrolysis. Compounds 1 and 2 have been characterized by elemental analysis, and ESI-mass, Infrared and NMR spectroscopic techniques. Further, solid state structures of 1 and 2 have been established by single crystals X-ray diffraction studies.

  13. Air detoxification with nanosize TiO2 aerosol tested on mice.

    Besov, A S; Krivova, N A; Vorontsov, A V; Zaeva, O B; Kozlov, D V; Vorozhtsov, A B; Parmon, V N; Sakovich, G V; Komarov, V F; Smirniotis, P G; Eisenreich, N


    A method for fast air purification using high concentration aerosol of TiO(2) nanoparticles is evaluated in a model chemical catastrophe involving toxic vapors of diisopropyl fluorophosphate (DFP). Mice are used as human model in a closed 100 dm(3) chamber. Exposure of mice to 37 ppm of DFP vapor for 15 min resulted in acute poisoning. Spraying TiO(2) aerosol in 2 min after the start of exposure to DFP vapors resulted in quick removal of DFP vapors from the chamber's air. Animals did not show signs of poisoning after the decontamination experiment and exposure to TiO(2) aerosol alone. Reactive oxygen species (ROS) and antioxidant activity (AOA) of mice blood plasma were measured for animals exposed to sound of aerosol generator, DFP vapors, TiO(2) aerosol and DFP vapors+TiO(2) aerosol. Reduced ROS and increased AOA were found for mice exposure to sound, DFP and TiO(2) aerosol. Exposure to DFP and decontamination with TiO(2) nanoparticles resulted in decreased AOA in 48 h following the exposure. The results suggest that application of TiO(2) aerosol is a powerful method of air purification from toxic hydrolysable compounds with moderate health aftermaths and requires further study and optimization.

  14. Biomimetic peptide-based models of [FeFe]-hydrogenases: utilization of phosphine-containing peptides.

    Roy, Souvik; Nguyen, Thuy-Ai D; Gan, Lu; Jones, Anne K


    Two synthetic strategies for incorporating diiron analogues of [FeFe]-hydrogenases into short peptides via phosphine functional groups are described. First, utilizing the amine side chain of lysine as an anchor, phosphine carboxylic acids can be coupled via amide formation to resin-bound peptides. Second, artificial, phosphine-containing amino acids can be directly incorporated into peptides via solution phase peptide synthesis. The second approach is demonstrated using three amino acids each with a different phosphine substituent (diphenyl, diisopropyl, and diethyl phosphine). In total, five distinct monophosphine-substituted, diiron model complexes were prepared by reaction of the phosphine-peptides with diiron hexacarbonyl precursors, either (μ-pdt)Fe2(CO)6 or (μ-bdt)Fe2(CO)6 (pdt = propane-1,3-dithiolate, bdt = benzene-1,2-dithiolate). Formation of the complexes was confirmed by UV/Vis, FTIR and (31)P NMR spectroscopy. Electrocatalysis by these complexes is reported in the presence of acetic acid in mixed aqueous-organic solutions. Addition of water results in enhancement of the catalytic rates.

  15. Fibrinolysis and anticoagulant potential of a metallo protease produced by Bacillus subtilis K42

    Wesam A Hassanein; Essam Kotb; Nadia M Awny; Yehia A El-Zawahry


    In this study, a potent fibrinolytic enzyme-producing bacterium was isolated from soybean flour and identified as Bacillus subtilis K42 and assayed in vitro for its thrombolytic potential. The molecular weight of the purified enzyme was 20.5 kDa and purification increased its specific activity 390-fold with a recovery of 14%. Maximal activity was attained at a temperature of 40°C (stable up to 65°C) and pH of 9.4 (range: 6.5–10.5). The enzyme retained up to 80% of its original activity after pre-incubation for a month at 4°C with organic solvents such as diethyl ether (DE), toluene (TO), acetonitrile (AN), butanol (BU), ethyl acetate (EA), ethanol (ET), acetone (AC), methanol (ME), isopropanol (IP), diisopropyl fluorophosphate (DFP), tosyl-lysyl-chloromethylketose (TLCK), tosyl-phenylalanyl chloromethylketose (TPCK), phenylmethylsulfonylfluoride (PMSF) and soybean trypsin inhibitor (SBTI). Aprotinin had little effect on this activity. The presence of ethylene diaminetetraacetic acid (EDTA), a metal-chelating agent and two metallo protease inhibitors, 2,2′-bipyridine and -phenanthroline, repressed the enzymatic activity significantly. This, however, could be restored by adding Co2+ to the medium. The clotting time of human blood serum in the presence of this enzyme reached a relative PTT of 241.7% with a 3.4-fold increase, suggesting that this enzyme could be an effective antithrombotic agent.

  16. Screening for Ricinoleic Acid as a Chemical Marker for Secale cornutum in Rye by High-Performance Thin-Layer Chromatography with Fluorescence Detection.

    Oellig, Claudia


    Ricinoleic acid as the characteristic fatty acid of Secale cornutum oil is a good marker for Secale cornutum impurities in cereal. The presented screening for ricinoleic acid in rye by high-performance thin-layer chromatography with fluorescence detection (HPTLC-FLD) offers a selective and sensitive method for the determination of Secale cornutum and is very different from existing gas chromatographic analyses. Lipid extraction was followed by transesterification and solid-phase extraction cleanup; thereafter, extracts were selectively derivatized with 2-naphthoyl chloride and analyzed by HPTLC-FLD with silica gel plates and cyclohexane/diisopropyl ether/formic acid (86:14:1, v/v/v) as mobile phase. For quantitation, the enhanced fluorescence was scanned at 280/>340 nm. Limits of detection and quantitation of 0.1 and 0.4 mg ricinoleic acid/kg of rye were obtained, which enables the determination of Secale cornutum far below the maximum admitted level. With near-100% recoveries and low standard deviations at relevant spiking levels, reliable results were guaranteed.

  17. 1,3-Substituted Imidazolidine-2,4,5-triones: Synthesis and Inhibition of Cholinergic Enzymes

    Josef Jampilek


    Full Text Available A series of novel and highly active acetylcholinesterase and butyrylcholinesterase inhibitors derived from substituted benzothiazoles containing an imidazolidine-2,4,5-trione moiety were synthesized and characterized. The molecular structure of 1-(2,6-diisopropyl-phenyl-3-[(1R-1-(6-fluoro-1,3-benzothiazol-2-ylethyl]-imidazolidine-2,4,5-trione (3g was determined by single-crystal X-ray diffraction. Both optical isomers are present as two independent molecules in the triclinic crystal system. The lipophilicity of the compounds was determined as the partition coefficient log Kow using the traditional shake-flask method. The in vitro inhibitory activity on acetylcholinesterase from electric eel and butyrylcholinesterase isolated from equine serum was determined. The inhibitory activity on acetylcholinesterase was significantly higher than that of the standard drug rivastigmine. The discussed compounds are also promising inhibitors of butyrylcholinesterase, as some of the prepared compounds inhibit butyrylcholinesterase better than the internal standards rivastigmine and galanthamine. The highest inhibitory activity (IC50 = 1.66 μmol/L corresponds to the compound 1-(4-isopropylphenyl-3-[(R-1-(6-fluorobenzo[d]thiazol-2-ylethyl]imidazolidine-2,4,5-trione (3d. For all the studied compounds, the relationships between the lipophilicity and the chemical structure as well as their structure-activity relationships are discussed.

  18. Separation and Characterization of Two Endopeptidases from Cotyledons of Germinating Vigna mungo Seeds.

    Mitsuhashi, W; Koshiba, T; Minamikawa, T


    Two major endopeptidases were present in cotyledons of germinating Vigna mungo seeds, as detected by the zymogram after polyacrylamide gel electrophoresis. They were not detectable in cotyledons of dry seeds, but their intensities on the zymogram increased during germination. During incubation of detached cotyledons, however, the activities showed only a slight increase for 5 days. These two endopeptidases could be separated by Sephacryl S-200 column chromatography. One of them was found to be a serine-endopeptidase as judged by phenylmethylsulfonylfluoride and diisopropyl fluorophosphate inhibition. The other was a sulfhydryl-endopeptidase because of its dependency on 2-mercaptoethanol and inhibition by leupeptin, chymostatin, and antipain. Analysis by sodium dodecyl sulfate polyacrylamide gel electrophoresis indicatd that the two endopeptidases digested the Vigna mungo seed globulin subunits at different rates. The serine enzyme digested the 56 kilodalton subunit at first, but the sulfhydryl enzyme digested the 54 kilodalton peptide more efficiently than the 56 kilodalton peptide. The pattern of digestion of globulin by the combination of the serine- and sulfhydryl-endopeptidases was similar to that using crude enzyme extracts.

  19. Separation and Characterization of Two Endopeptidases from Cotyledons of Germinating Vigna mungo Seeds 1

    Mitsuhashi, Wataru; Koshiba, Tomokazu; Minamikawa, Takao


    Two major endopeptidases were present in cotyledons of germinating Vigna mungo seeds, as detected by the zymogram after polyacrylamide gel electrophoresis. They were not detectable in cotyledons of dry seeds, but their intensities on the zymogram increased during germination. During incubation of detached cotyledons, however, the activities showed only a slight increase for 5 days. These two endopeptidases could be separated by Sephacryl S-200 column chromatography. One of them was found to be a serine-endopeptidase as judged by phenylmethylsulfonylfluoride and diisopropyl fluorophosphate inhibition. The other was a sulfhydryl-endopeptidase because of its dependency on 2-mercaptoethanol and inhibition by leupeptin, chymostatin, and antipain. Analysis by sodium dodecyl sulfate polyacrylamide gel electrophoresis indicatd that the two endopeptidases digested the Vigna mungo seed globulin subunits at different rates. The serine enzyme digested the 56 kilodalton subunit at first, but the sulfhydryl enzyme digested the 54 kilodalton peptide more efficiently than the 56 kilodalton peptide. The pattern of digestion of globulin by the combination of the serine- and sulfhydryl-endopeptidases was similar to that using crude enzyme extracts. Images Fig. 2 Fig. 3 Fig. 6 Fig. 7 PMID:16664675

  20. Infrared microcalorimetric spectroscopy using uncooled thermal detectors

    Datskos, P.G. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Physics and Astronomy]|[Oak Ridge National Lab., TN (United States); Rajic, S.; Datskou, I.; Egert, C.M. [Oak Ridge National Lab., TN (United States)


    The authors have investigated a novel infrared microcalorimetric spectroscopy technique that can be used to detect the presence of trace amounts of target molecules. The chemical detection is accomplished by obtaining the infrared photothermal spectra of molecules absorbed on the surface of an uncooled thermal detector. Traditional gravimetric based chemical detectors (surface acoustic waves, quartz crystal microbalances) require highly selective coatings to achieve chemical specificity. In contrast, infrared microcalorimetric based detection requires only moderately specific coatings since the specificity is a consequence of the photothermal spectrum. They have obtained infrared photothermal spectra for trace concentrations of chemical analytes including diisopropyl methylphosphonate (DIMP), 2-mercaptoethanol and trinitrotoluene (TNT) over the wavelength region2.5 to 14.5 {micro}m. They found that in the wavelength region 2.5 to 14.5 {micro}m DIMP exhibits two strong photothermal peaks. The photothermal spectra of 2-mercaptoethanol and TNT exhibit a number of peaks in the wavelength region 2.5 to 14.5 {micro}m and the photothermal peaks for 2-mercaptoethanol are in excellent agreement with infrared absorption peaks present in its IR spectrum. The photothermal response of chemical detectors based on microcalorimetric spectroscopy has been found to vary reproducibly and sensitively as a consequence of adsorption of small number of molecules on a detector surface followed by photon irradiation and can be used for improved chemical characterization.

  1. Efficient photochemical generation of peroxycarboxylic nitric anhydrides with ultraviolet light emitting diodes

    N. D. Rider


    Full Text Available Photochemical sources of peroxycarboxylic nitric anhydrides (PANs are utilized in many atmospheric measurement techniques for calibration or to deliver an internal standard. Conventionally, such sources rely on phosphor-coated low-pressure mercury (Hg lamps to generate the UV light necessary to photo-dissociate a dialkyl ketone (usually acetone in the presence of a calibrated amount of nitric oxide (NO and oxygen (O2. In this manuscript, a photochemical PAN source in which the Hg lamp has been replaced by arrays of ultraviolet light-emitting diodes (UV-LEDs is described. The output of the UV-LED source was analyzed by gas chromatography (PAN-GC and thermal dissociation cavity ring-down spectroscopy (TD-CRDS. Using acetone, diethyl ketone (DIEK, diisopropyl ketone (DIPK, or di-n-propyl ketone (DNPK, respectively, the source produces peroxyacetic (PAN, peroxypropionic (PPN, peroxyisobutanoic (PiBN, or peroxy-n-butanoic nitric anhydride (PnBN from NO in high yield (> 90%. Box model simulations with a subset of the Master Chemical Mechanism (MCM were carried out to rationalize products yields and to identify side products. The use of UV-LED arrays offers many advantages over conventional Hg lamp setups, including greater light output over a narrower wavelength range, lower power consumption, and minimal generation of heat.

  2. 异丙醚提纯工艺的研究%Research Isopropyl Ether Purification Process

    姜丽敏; 位淑华; 张梦博


    研究了异丙醚的提纯工艺。采用酸洗的方法,用硫酸做酸化剂与异丙醇副产叠合油中的异丙醚反应,静止分离,水解,精馏得到高纯度的异丙醚。讨论了硫酸质量分数、硫酸与异丙醚的质量比、反应时间对反应的影响,所得异丙醚的质量分数大于99%。%Purification process of isopropyl ether was studied.Sulfuric acid as acidifying reagent reac-ted with isopropyl ether in composite oil which was a byproduct of isopropanol,after still separation,hydroly-sis,distillation,isopropyl ether with high purity was obtained.The content of sulfuric acid,the mass ratio of sulfuric acid to isopropyl ether,the reaction time were discussed,the obtained content of diisopropyl ether was greater than 99%.

  3. A Novel PEGylation Method for Improving the Pharmacokinetic Properties of Anti-Interleukin-17A RNA Aptamers.

    Haruta, Kazuhiko; Otaki, Natsuki; Nagamine, Masakazu; Kayo, Tomoyoshi; Sasaki, Asako; Hiramoto, Shinsuke; Takahashi, Masayuki; Hota, Kuniyoshi; Sato, Hideaki; Yamazaki, Hiroaki


    The obstacles to the development of therapeutic aptamers for systemic inflammatory diseases, such as nuclease degradation and renal clearance, have not been fully overcome. Here, we report a novel PEGylation method, sbC-PEGylation, which improves the pharmacokinetic properties of RNA aptamers that act against interleukin-17A (IL-17A) in mice and monkeys. sbC-PEGylated aptamers were synthesized by coupling the symmetrical branching molecule 2-cyanoethyl-N,N-diisopropyl phosphoroamidite to the 5' end of the aptamer, before conjugating two polyethylene glycol (PEG) molecules to the aptamer. Pharmacokinetic studies showed that compared with conventionally PEGylated aptamers, the sbC-PEGylated aptamer exhibited excellent stability in the blood circulation of mice and monkeys. In addition, one of the sbC-PEGylated aptamers, 17M-382, inhibited the interleukin-6 (IL-6) production induced by IL-17A in NIH3T3 cells in a concentration-dependent manner, and the half-maximal inhibitory concentration of sbC-PEGylated 17M-382 was two times lower than that of non-PEGylated 17M-382. Furthermore, the intraperitoneal administration of sbC-PEGylated 17M-382 significantly inhibited the IL-6 production induced by IL-17A in a mouse air pouch model. Our findings suggest that the novel PEGylation method described in this study, sbC-PEGylation, could be used to develop anti-IL-17A aptamers as a therapeutic option for systemic inflammatory disease.

  4. Molecular and crystal structure of gossypol tetramethyl ether with an unknown solvate

    Muhabbat Honkeldieva


    Full Text Available The title compound, C34H38O8 (systematic name: 5,5′-diisopropyl-2,2′,3,3′-tetramethoxy-7,7′-dimethyl-2H,2′H-8,8′-bi[naphtho[1,8-bc]furan]-4,4′-diol, has been obtained from a gossypol solution in a mixture of dimethyl sulfate and methanol. The molecule is situated on a twofold rotation axis, so the asymmetric unit contains one half-molecule. In the molecule, the hydroxy groups are involved in intramolecular O—H...O hydrogen bonds, and the two naphthyl fragments are inclined each to other by 83.8 (1°. In the crystal, weak C—H...O and C—H...π interactions consolidate the packing, which exhibits channels with an approximate diameter of 6 Å extending along the c-axis direction. These channels are filled with highly disordered solvent molecules, so their estimated scattering contribution was subtracted from the observed diffraction data using the SQUEEZE option in PLATON [Spek, A. L. (2015. Acta Cryst. C71, 9–18].

  5. 杀螨剂联苯肼酯的合成研究%Study on Synthesis of Miticide Bifenazate

    王元元; 高宁; 李辉辉; 冯根锋; 肖亚平


    Four routes to the synthesis of bifenazate were screened. An efficient and scalable process was obtained starting from the methylation of 4 -phenylphenol, followed by the reaction with diisopropyl azodicarcoxylate (DIAD) under catalysis of a Lewis acid, and then selective decarboxylation. The structure of product was confirmed with 'H NMR.%通过比较联苯肼酯的4种不同合成方法,选择以对羟基联苯为原料,经甲基化得到4-甲氧基联苯,在路易斯酸的催化下与偶氮二甲酸二异丙酯(DIAD)进行胺化反应,最后选择性脱羧得到联苯肼酯的工艺路线,总收率达12.4%,产品含量98%以上.该路线适合工业化生产.

  6. Synthesis of a new intercalating nucleic acid 6H-INDOLO[2,3-b] quinoxaline oligonucleotides to improve thermal stability of Hoogsteen-type triplexes.

    Osman, Amany M A; Pedersen, Erik B; Bergman, Jan


    A new intercalating nucleic acid monomer X was obtained in high yield starting from alkylation of 4-iodophenol with (S)-(+)-2-(2,2-dimethyl-1,3-dioxolan-4-yl)ethanol under Mitsunobu conditions followed by hydrolysis with 80% aqueous acetic acid to give a diol which was coupled under Sonogashira conditions with trimethylsilylacetylene (TMSA) to achieve the TMS protected (S)-4-(4-((trimethylsilyl)ethynyl)phenoxy)butane-1,2-diol. Tetrabutylammonium flouride was used to remove the silyl protecting group to obtain (S)-4-(4-ethynylphenoxy)butane-1,2-diol which was coupled under Sonogashira conditions with 2-(9-bromo-6H-indolo[2,3-b]quinoxalin-6-yl)-N,N-dimethylethanamine to achieve (S)-4-(4-((6-(2-(dimethylamino)ethyl)-6H-indolo[2,3-b]quinoxalin-9-yl)ethynyl)phenoxy)butane-1,2-diol. This compound was tritylated with 4,4'-dimethoxytrityl chloride followed by treatment with 2-cyanoethyltetraisopropylphosphordiamidite in the presence of N,N'-diisopropyl ammonium tetrazolide to afford the corresponding phosphoramidite. This phosphoramidite was used to insert the monomer X into an oligonucleotide which was used for thermal denaturation studies of a corresponding parallel triplex.

  7. High-performance intrinsically microporous dihydroxyl-functionalized triptycene-based polyimide for natural gas separation

    Alaslai, Nasser Y.


    A novel polyimide of intrinsic microporosity (PIM-PI) was synthesized from a 9,10-diisopropyl-triptycene-based dianhydride (TPDA) and dihydroxyl-functionalized 4,6-diaminoresorcinol (DAR). The unfunctionalized TPDA-m-phenylenediamine (mPDA) polyimide derivative was made as a reference material to evaluate the effect of the OH group in TPDA-DAR on its gas transport properties. Pure-gas permeability coefficients of He, H2, N2, O2, CH4, and CO2 were measured at 35 °C and 2 atm. The BET surface area based on nitrogen adsorption of dihydroxyl-functionalized TPDA-DAR (308 m2g-1) was 45% lower than that of TPDA-mPDA (565 m2g-1). TPDA-mPDA had a pure-gas CO2 permeability of 349 Barrer and CO2/CH4 selectivity of 32. The dihydroxyl-functionalized TPDA-DAR polyimide exhibited enhanced pure-gas CO2/CH4 selectivity of 46 with a moderate decrease in CO2 permeability to 215 Barrer. The CO2 permeability of TPDA-DAR was ∼30-fold higher than that of a commercial cellulose triacetate membrane coupled with 39% higher pure-gas CO2/CH4 selectivity. The TPDA-based dihydroxyl-containing polyimide showed good plasticization resistance and maintained high mixed-gas selectivity of 38 when tested at a typical CO2 natural gas wellhead CO2 partial pressure of 10 atm.

  8. Health assessment of gasoline and fuel oxygenate vapors: neurotoxicity evaluation.

    O'Callaghan, James P; Daughtrey, Wayne C; Clark, Charles R; Schreiner, Ceinwen A; White, Russell


    Sprague-Dawley rats were exposed via inhalation to vapor condensates of either gasoline or gasoline combined with various fuel oxygenates to assess potential neurotoxicity of evaporative emissions. Test articles included vapor condensates prepared from "baseline gasoline" (BGVC), or gasoline combined with methyl tertiary butyl ether (G/MTBE), ethyl t-butyl ether (G/ETBE), t-amyl methyl ether (G/TAME), diisopropyl ether (G/DIPE), ethanol (G/EtOH), or t-butyl alcohol (G/TBA). Target concentrations were 0, 2000, 10,000 or 20,000mg/mg(3) and exposures were for 6h/day, 5days/week for 13weeks. The functional observation battery (FOB) with the addition of motor activity (MA) testing, hematoxylin and eosin staining of brain tissue sections, and brain regional analysis of glial fibrillary acidic protein (GFAP) were used to assess behavioral changes, traditional neuropathology and astrogliosis, respectively. FOB and MA data for all agents, except G/TBA, were negative. G/TBA behavioral effects resolved during recovery. Neuropathology was negative for all groups. Analyses of GFAP revealed increases in multiplebrain regions largely limited to males of the G/EtOH group, findings indicative of minor gliosis, most significantly in the cerebellum. Small changes (both increases and decreases) in GFAP were observed for other test agents but effects were not consistent across sex, brain region or exposure concentration.

  9. Health assessment of gasoline and fuel oxygenate vapors: subchronic inhalation toxicity.

    Clark, Charles R; Schreiner, Ceinwen A; Parker, Craig M; Gray, Thomas M; Hoffman, Gary M


    Sprague Dawley rats were exposed via inhalation to vapor condensates of either gasoline or gasoline combined with various fuel oxygenates to assess whether their use in gasoline influences the hazard of evaporative emissions. Test substances included vapor condensates prepared from an EPA described "baseline gasoline" (BGVC), or gasoline combined with methyl tertiary butyl ether (G/MTBE), ethyl t-butyl ether (G/ETBE), t-amyl methyl ether (G/TAME), diisopropyl ether (G/DIPE), ethanol (G/EtOH), or t-butyl alcohol (G/TBA). Target concentrations were 0, 2000, 10,000 or 20,000mg/m(3) and exposures were for 6h/day, 5days/week for 13weeks. A portion of the animals were maintained for a four week recovery period to determine the reversibility of potential adverse effects. Increased kidney weight and light hydrocarbon nephropathy (LHN) were observed in treated male rats in all studies which were reversible or nearly reversible after 4weeks recovery. LHN is unique to male rats and is not relevant to human toxicity. The no observed effect level (NOAEL) in all studies was 10,000mg/m(3), except for G/MTBE (gasoline alone.

  10. Health assessment of gasoline and fuel oxygenate vapors: micronucleus and sister chromatid exchange evaluations.

    Schreiner, Ceinwen A; Hoffman, Gary M; Gudi, Ramadevi; Clark, Charles R


    Micronucleus and sister chromatid exchange (SCE) tests were performed for vapor condensate of baseline gasoline (BGVC), or gasoline with oxygenates, methyl tert-butyl ether (G/MTBE), ethyl tert butyl ether (G/ETBE), t-amyl methyl ether (G/TAME), diisopropyl ether (G/DIPE), t-butyl alcohol (TBA), or ethanol (G/EtOH). Sprague Dawley rats (the same 5/sex/group for both endpoints) were exposed to 0, 2000, 10,000, or 20,000mg/m(3) of each condensate, 6h/day, 5days/week over 4weeks. Positive controls (5/sex/test) were given cyclophosphamide IP, 24h prior to sacrifice at 5mg/kg (SCE test) and 40mg/kg (micronucleus test). Blood was collected from the abdominal aorta for the SCE test and femurs removed for the micronucleus test. Blood cell cultures were treated with 5μg/ml bromodeoxyuridine (BrdU) for SCE evaluation. No significant increases in micronucleated immature erythrocytes were observed for any test material. Statistically significant increases in SCE were observed in rats given BGVC alone or in female rats given G/MTBE. G/TAME induced increased SCE in both sexes at the highest dose only. Although DNA perturbation was observed for several samples, DNA damage was not expressed as increased micronuclei in bone marrow cells. Inclusion of oxygenates in gasoline did not increase the effects of gasoline alone or produce a cytogenetic hazard.

  11. A Colorimetric Sensor for Qualitative Discrimination and Quantitative Detection of Volatile Amines

    Zhonglin Tang


    Full Text Available We have developed a novel colorimetric sensor based on a digital camera and white LED illumination. Colorimetric sensor arrays (CSAs were made from a set of six chemically responsive dyes impregnated on an inert substrate plate by solution casting. Six common amine aqueous solutions, including dimethylamine, triethylamine, diisopropyl-amine, aniline, cyclohexylamine, and pyridine vaporized at 25 °C and six health-related trimethylamine (TMA concentrations including 170 ppm, 51 ppm, 8 ppm, 2 ppm, 125 ppb and 50 ppb were analyzed by the sensor to test its ability for the qualitative discrimination and quantitative detection of volatile amines. We extracted the feature vectors of the CSA's response to the analytes from a fusional color space, which was obtained by conducting a joint search algorithm of sequential forward selection and sequential backward selection (SFS&SBS based on the linear discriminant criteria (LDC in a mixed color space composed of six common color spaces. The principle component analysis (PCA followed by the hierarchical cluser analysis (HCA were utilized to discriminate 12 analytes. Results showed that the colorimetric sensor grouped the six amine vapors and five TMA concentrations correctly, while TMA concentrations of 125 ppb and 50 ppb were indiscriminable from each other. The limitation of detection (LOD of the sensor for TMA was found to be lower than 50 ppb. The CSAs were reusable for TMA concentrations below 8 ppm.

  12. Tailored Fabrication of Thoroughly Mesoporous BiVO4 Nanofibers and Their Visible-Light Photocatalytic Activities.

    Liu, Huabing; Hou, Huilin; Gao, Fengmei; Yao, Xiaohong; Yang, Weiyou


    Bismuth vanadate (BiVO4) is considered as a potentially attractive candidate for the O2 evolution and photodegradation of organic pollutants. In an effort to develop visible-light-driven photocatalysts with high activities, the thoroughly mesoporous BiVO4 nanofibers were fabricated via a foaming-assisted electrospinning strategy. It was found that the introduced foaming agent of diisopropyl azodiformate within the solutions plays a crucial role on the formation of thoroughly mesoporous BiVO4 nanofibers, making their growth tunable. The obtained mesoporous BiVO4 nanofibers possess well-defined one-dimensional mesoporous architectures with high purity in their morphology and a surface area of 22.5 m(2)/g, which is ∼4 times that of conventional solid counterparts (5.8 m(2)/g). Accordingly, they exhibit much higher efficient photocatalytic activities toward the degradation of rhodamine B under visible-light irradiation, which is 3 times that of conventional solid counterparts, suggesting their promising application as novel and efficient photocatalysts for water purification.

  13. Kinetic Studies on the Irreversible Inhibition of Restriction Endonuclease Pst I by Site-Specific Inhibitors


    The irreversible modifying effects on Pst I of several inhibitors have been studied with the irreversible inhibition kinetic theory of single substrate reaction provided by Tsou,C. L. Pyridoxal phosphate (PLP), p-chloromercuribenzoic acid (PCMB),diisopropyl fluorophosphate (DFP), 2,3-diacetyl (DAC) and N-ethyl-5-phenylisoxazoliun-3'-sulfonate (woodward's reagent K, WRK ) modify the lysine, cysine,serteine, arginine and carboxyl groups of the protein molecule respectively. These five inhibitors have been found to inhibit both the prime activity and star activity of Pst 1. Used with the irreversible inhibition theory,the apparent inhibition rate constant, A and the microcosmic inhibition rate constants, k+0 and k′ +o of every inhibitor were calculated. We also found that their inhibition effects belong to the noncompetitive irreversible inhibition. Results show that among the groups to be modified, some have nothing to do with the combination with the substrate, and some may have, but any of them isn't the only factor involved in the specific binding.Despite all this, they may take part in the catalysis of enzyme or have important effects on maintaining the active structure of enzyme molecules. Furthermore, serine and arginine residues are related to the alteration of Pst I conformation and then influence the ability of Pst I recognizing and incising DNA specifically.

  14. Cytochrome P450 inhibition potential of new psychoactive substances of the tryptamine class.

    Dinger, Julia; Woods, Campbell; Brandt, Simon D; Meyer, Markus R; Maurer, Hans H


    New psychoactive substances (NPS) are not tested for their cytochrome P450 (CYP) inhibition potential before consumption. Therefore, this potential was explored for tryptamine-derived NPS (TDNPS) including alpha-methyl tryptamines (AMTs), dimethyl tryptamines (DMTs), diallyl tryptamines (DALTs), and diisopropyl tryptamines (DiPTs) using test substrates preferred by the Food and Drug Administration in a cocktail assay. All tested TDNPS with the exception of DMT inhibited CYP2D6 activity with IC50 values below 100μM. DALTs inhibited CYP2D6 activity similar to paroxetine and quinidine and CYP1A2 activity comparable to fluvoxamine. 5-Methoxy-N,N-diallyltryptamine reduced in vivo the caffeine metabolism in rats consistent with in vitro results. Five of the AMTs also inhibited CYP1A2 activity comparable to amiodarone. AMT and 6-F-AMT inhibited CYP2A6 activity in the range of the test inhibitor tranylcypromine. CYP2B6 activity was inhibited by 19 tryptamines, but weakly compared to efavirenz. CYP2C8 activity was inhibited by five of the tested TDNPS and three showed values comparable to trimethoprim and gemfibrozil. Six tryptamines inhibited CYP2C9 and seven CYP2C19 activities comparable to fluconazole and chloramphenicol, respectively. Nineteen compounds showed inhibition of CYP2E1 and 18 of CYP3A activity, respectively. These results showed that the CYP inhibition by TDNPS might be clinically relevant, but clinical studies are needed to explore this further.

  15. Mol-ecular and crystal structure of gossypol tetra-methyl ether with an unknown solvate.

    Honkeldieva, Muhabbat; Talipov, Samat; Mardanov, Rustam; Ibragimov, Bakhtiyar


    The title compound, C34H38O8 (systematic name: 5,5'-diisopropyl-2,2',3,3'-tetra-meth-oxy-7,7'-dimethyl-2H,2'H-8,8'-bi-[naphtho-[1,8-bc]furan]-4,4'-diol), has been obtained from a gossypol solution in a mixture of dimethyl sulfate and methanol. The mol-ecule is situated on a twofold rotation axis, so the asymmetric unit contains one half-mol-ecule. In the mol-ecule, the hy-droxy groups are involved in intra-molecular O-H⋯O hydrogen bonds, and the two naphthyl fragments are inclined each to other by 83.8 (1)°. In the crystal, weak C-H⋯O and C-H⋯π inter-actions consolidate the packing, which exhibits channels with an approximate diameter of 6 Å extending along the c-axis direction. These channels are filled with highly disordered solvent mol-ecules, so their estimated scattering contribution was subtracted from the observed diffraction data using the SQUEEZE option in PLATON [Spek, A. L. (2015). Acta Cryst. C71, 9-18].

  16. A new acylamidase from Rhodococcus erythropolis TA37 can hydrolyze N-substituted amides.

    Lavrov, K V; Zalunin, I A; Kotlova, E K; Yanenko, A S


    A new acylamidase was isolated from Rhodococcus erythropolis TA37 and characterized. N-Substituted acrylamides (isopropyl acrylamide, N,N-dimethyl-aminopropyl acrylamide, and methylene-bis-acrylamide), acid para-nitroanilides (4'-nitroacetanilide, Gly-pNA, Ala-pNA, Leu-pNA), and N-acetyl derivatives of glycine, alanine, and leucine are good substrates for this enzyme. Aliphatic amides (acetamide, acrylamide, isobutyramide, n-butyramide, and valeramide) are also used as substrates but with less efficiency. The enzyme subunit mass by SDS-PAGE is 55 kDa. Maximal activity is exhibited at pH 7-8 and 55°C. The enzyme is stable for 15 h at 22°C and for 0.5 h at 45°C. The Michaelis constant (K(m)) is 0.25 mM with Gly-pNA and 0.55 mM with Ala-pNA. The acylamidase activity is suppressed by inhibitors of serine proteases (phenylmethylsulfonyl fluoride and diisopropyl fluorophosphate) but is not suppressed by inhibitors of aliphatic amidases (acetaldehyde and nitrophenyl disulfides). The N-terminal amino acid sequence of the acylamidase is highly homologous to those of two putative amidases detected from sequenced R. erythropolis genomes. It is suggested that the acylamidase together with the detected homologs forms a new class within the amidase signature family.

  17. A novel control of enzymatic enantioselectivity through the racemic temperature influenced by reaction media.

    Jin, Xin; Liu, Bokai; Ni, Zhong; Wu, Qi; Lin, Xianfu


    The influence of reaction media on the racemic temperature (T(r)) in the lipase-catalyzed resolution of ketoprofen vinyl ester was investigated. An effective approach to the control of the enzymatic enantioselectivity and the prediction of the increasing tendency was developed based on the T(r) influenced by reaction media. The T(r) for the resolution catalyzed by Candida rugosa lipase (CRL) was found at 29 °C in aqueous and S-ketoprofen was obtained predominantly at 40 °C. However, CRL showed R-selectivity at 40 °C in diisopropyl ether because the T(r) was changed to 56 °C. CRL, lipase from AYS Amano(®) and Mucor javanicus lipase were further applied for the investigation of the enzymatic enantioselectivity in dioxane, DIPE, isooctane and their mixed media with water. The effects of the reaction medium on T(r) could be related to the solvent hydrophobicity, the lipase conformational flexibility and the interaction between the enantiomers and the lipase.

  18. Acetylated and Methylated β-Cyclodextrins as Viable Soluble Supports for the Synthesis of Short 2′-Oligodeoxyribo-nucleotides in Solution

    Harri Lönnberg


    Full Text Available Novel soluble supports for oligonucleotide synthesis 11a–c have been prepared by immobilizing a 5′-O-protected 3′-O-(hex-5-ynoylthymidine (6 or 7 to peracetylated or permethylated 6-deoxy-6-azido-β-cyclodextrins 10a or 10b by Cu(I-promoted 1,3-dipolar cycloaddition. The applicability of the supports to oligonucleotide synthesis by the phosphoramidite strategy has been demonstrated by assembling a 3′-TTT-5′ trimer from commercially available 5′-O-(4,4′-dimethoxytritylthymidine 3′-phosphoramidite. To simplify the coupling cycle, the 5′-O-(4,4′-dimethoxytrityl protecting group has been replaced with an acetal that upon acidolytic removal yields volatile products. For this purpose, 5′-O-(1-methoxy-1-methylethyl-protected 3′-(2-cyanoethyl-N,N-diisopropyl-phosphoramidites of thymidine (5a, N4-benzoyl-2′-deoxycytidine (5b and N6-benzoyl-2′-deoxyadenosine (5c have been synthesized and utilized in synthesis of a pentameric oligonucleotide 3′-TTCAT-5′ on the permethylated cyclodextrin support 11c.

  19. Analysis and migration of phthalates in infant food packed in recycled paperboard.

    Gärtner, Sonja; Balski, Matthias; Koch, Matthias; Nehls, Irene


    The contamination of infant food with substances from its packaging due to migration processes is still a problem. Most recently, great attention was paid to the migration of epoxidized soybean oil (ESBO) and phthalates from twist-off closures into baby food packed in glass jars. Besides, packaging made of recycled fiber materials such as paper and paperboard were found to be the source of contaminants in dry and powdery foodstuffs such as sugar, rice, and maize flour. In this study 20 infant food samples packed in recycled paperboard containers were tested for phthalates and diisopropyl naphthalenes (DIPN), known incorporated substances in recycled paper. Furthermore, the barrier function of different secondary packaging materials (paper and aluminum-coated foil) was investigated. The highest contents of phthalates (mainly diisobutyl phthalate, DiBP) and DIPN in infant food samples were found for those foods packed in inner bags made of paper. Migration experiments were performed under authentic conditions to evaluate possible transfer mechanism (gas phase, direct contact) of phthalate esters into foodstuff. It is shown that paper does not provide an appropriate barrier against migration of semipolar compounds such as phthalates. The air space itself otherwise effectively prevents migration of the less volatile phthalates under the applied conditions.

  20. Bioaccumulation of stentorin, the probable causative agent for discolored (“purple”) eggs and ovaries in blue catfish (Ictalurus furcatus) from Eufaula Lake, Oklahoma, USA

    Gale, Robert W.; Papoulias, Diana M.; Schmitt, Christopher J.


    Observations of reddish to “purple” discolored eggs in the ovaries of adult female blue catfish (Ictalurus furcatus) from the northern arm of Eufaula Lake, a eutrophic multiuse impoundment in east-central Oklahoma, were first reported in 2006. Blue catfish eggs are normally cream to light yellow. Reports peaked in 2007–2008 and declined through 2009–2010; purple eggs have not been reported between 2010 and 2014. In the laboratory, all tissues and fluids of affected fish were strongly orange-red fluorescent under UV illumination, with the fluorescence most apparent in the lipid-rich ovaries and eggs. The causative agent was isolated chromatographically and confirmed by mass spectrometry as stentorin (1,3,4,6,8,10,11,13-octahydroxy-2,5-diisopropyl-phenanthro[1,10,9,8,o,p,q,r,a]perylene-7,14-dione), the fluorescent, lipophilic pigment associated with the photoreceptor protein of the ciliated protozoan Stentor coeruleus (Heterotrichea; Stentoridae). Larval medaka (Orizias latipes) readily consumed S. coeruleus in the laboratory and were observed to fluoresce in the same manner as the affected blue catfish. Potential deleterious effects of stentorin bioaccumulation remain to be determined, as do the geographic extent and the identities of other fluorescent compounds isolated from catfish eggs and ovaries.

  1. A reappraisal of the role of Pityrosporum orbiculare in pityriasis versicolor and the significance of extracellular lipase.

    Catterall, M D; Ward, M E; Jacobs, P


    Pityrosporum orbiculare is an obligate lipophilic yeast in vitro, which suggests it possesses an extracellular lipase crucial for nutrition. If present in vivo, the enzyme would enable the yeast to utilize skin surface lipids, which may therfore play an important role in the pathogenesis of pityriasis versicolor. Cultured P. orbiculare and biopsy material from patients with pityriasis versicolor were investigated for the presence of lipase by electron microscope histochemistry. At sites of lipase activity, fatty acid hydrolyzed from Tween 80 substrate reacts with Ca++ ions to form an insoluble Ca++ soap. Exchange of Ca++ with Pb++ enables the sites of lipase activity to be visualized as electron dense deposits of insoluble lead soap. Surface lipase activity was apparent when the technique was applied to P. orbiculare grown on lipid containing medium and its specificity confirmed by removal of substrate and inhibition by di-isopropyl fluorophosphate and quinine hydrochloride, but not by sodium fluoride. When the same technique was applied to stratum corneum infected with Pityrosporum furfur (Malassez), no reaction product could be detected. It is postulated that lipase, although critical for fungal nutrition in vitro, is unlikely to be of importance in vivo. Skin surface lipids are therefore probably not relevant to the pathogenesis of pityriasis versicolor.

  2. 郁李仁(R)-醇腈酶高效催化乙酰基三甲基硅烷与丙酮氰醇不对称转氰%Highly Efficient Asymmetric Transcyanation of Acetyltrimethylsilane with Acetone Cyanohydrin Catalyzed by (R)-Oxynitrilase from Prunus Japonica Seed Meal

    黄舜荣; 吴虹; 宗敏华


    Highly efficient asymmetric transcyanation of acetyltrimethylsilane with acetone cyanohydrin in an aqueous/organic biphasic system catalyzed with (R)-oxynitrilase from defatted Prunus Japonica seed meal for the preparation of optically active (R)-2-trimethylsilyl-2-hydroxyl- propionitrile was successfully carried out for the first time. For better understanding of the reaction, various influential variables were examined with respect to the initial reaction rate, the substrate conversion and the product enantiomeric excess (e.e.). Diisopropyl ether was found to be the best organic phase for this reaction among all the organic solvents tested. The optimal concentrations of Prunus Japonica seed meal powder, acetyltrimethylsilane and acetone cyanohydrin, volume ratio of aqueous phase 13% (by volume), 5.0 and 30℃, respectively, while the initial reaction rate, the substrate conversion and the product enantiomeric excess were 1.34mmol. L-1.h-1, 99.0% and 99.0%, respectively. The comparative study demonstrated that silicon atom in substrate showed great effect on the reaction and acetyltrimethylsilane was a much better substrate for (R)-hydroxynitrile lyase from Prunus Japonica seed than its carbon analogue 3,3-dimethyl-2-butanone.


    Shao-hua Huang; Zheng-wu Bai; Chuan-qi Yin; Shi-rong Li


    Two polyurethanes of different molecular weights were prepared by the copolymerization of phenyl diisocyanate and diisopropyl tartrate. The polyurethanes having terminal isocyanate groups were reacted with 3-aminopropyl silica gel to afford two chiral stationary phases. The (M-)n of the two polyurethanes were 4057 g/mol and 6442 g/mol. The polyurethanes and the corresponding chiral stationary phases were characterized by FT-IR, 1H NMR and elemental analysis. The loading capacities of the polyurethanes on silica gel were 0.68 mmol units/g and 0.61 mmol units/g, respectively. The separation performance and the influence of additives, triethylamine and trichloroacetic acid, on the separation of chiral compounds were investigated by HPLC. The chiral stationary phase prepared from polyurethane with (M-)n of 4057 g/mol demonstrated better enantioseparation capability than that with (M-)n of 6442 g/mol. Additionally, it was found that the addition of triethylamine and trichloroacetic acid in the mobile phases significantly improved the enantioseparation for these two chiral stationary phases.

  4. Tyrosine 547 constitutes an essential part of the catalytic mechanism of dipeptidyl peptidase IV.

    Bjelke, Jais R; Christensen, Jesper; Branner, Sven; Wagtmann, Nicolai; Olsen, Christina; Kanstrup, Anders B; Rasmussen, Hanne B


    Human dipeptidyl peptidase IV (DPP-IV) is a ubiquitously expressed type II transmembrane serine protease. It cleaves the penultimate positioned prolyl bonds at the N terminus of physiologically important peptides such as the incretin hormones glucagon-like peptide 1 and glucose-dependent insulinotropic peptide. In this study, we have characterized different active site mutants. The Y547F mutant as well as the catalytic triad mutants S630A, D708A, and H740L showed less than 1% wild type activity. X-ray crystal structure analysis of the Y547F mutant revealed no overall changes compared with wild type apoDPP-IV, except the ablation of the hydroxyl group of Tyr(547) and a water molecule positioned in close proximity to Tyr(547). To elucidate further the reaction mechanism, we determined the crystal structure of DPP-IV in complex with diisopropyl fluorophosphate, mimicking the tetrahedral intermediate. The kinetic and structural findings of the tyrosine residue are discussed in relation to the catalytic mechanism of DPP-IV and to the inhibitory mechanism of the 2-cyanopyrrolidine class of potent DPP-IV inhibitors, proposing an explanation for the specificity of this class of inhibitors for the S9b family among serine proteases.

  5. The coupling of direct analysis in real time ionization to Fourier transform ion cyclotron resonance mass spectrometry for ultrahigh-resolution mass analysis.

    Rummel, Julia L; McKenna, Amy M; Marshall, Alan G; Eyler, John R; Powell, David H


    Direct Analysis in Real Time (DART) is an ambient ionization technique for mass spectrometry that provides rapid and sensitive analyses with little or no sample preparation. DART has been reported primarily for mass analyzers of low to moderate resolving power such as quadrupole ion traps and time-of-flight (TOF) mass spectrometers. In the current work, a custom-built DART source has been successfully coupled to two different Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometers for the first time. Comparison of spectra of the isobaric compounds, diisopropyl methylphosphonate and theophylline, acquired by 4.7 T FT-ICR MS and TOF MS, demonstrates that the TOF resolving power can be insufficient for compositionally complex samples. 9.4 T FT-ICR MS yielded the highest mass resolving power yet reported with DART ionization for 1,2-benzanthracene and 9,10-diphenylanthracene. Polycyclic aromatic hydrocarbons exhibit a spatial dependence in ionization mechanisms between the DART source and the mass spectrometer. The feasibility of analyzing a variety of samples was established with the introduction and analysis of food products and crude oil samples. DART FT-ICR MS provides complex sample analysis that is rapid, highly selective and information-rich, but limited to relatively low-mass analytes.

  6. Interaction of murine intestinal mast cell proteinase with inhibitors (serpins) in blood; analysis by SDS-PAGE and western blotting.

    Irvine, J; Newlands, G F; Huntley, J F; Miller, H R


    The interaction of mouse intestinal mast cell proteinase (IMCP) with serine proteinase inhibitors (serpins) in blood was analysed: (i) by examining the capacity of the inhibitors in blood to block the binding of the irreversible serine esterase inhibitor [3H]diisopropyl fluorophosphate (DFP); (ii) by Western blotting. The binding of [3H]DFP to IMCP was blocked very rapidly by inhibitors in mouse serum and, by Western blotting, this inhibition was associated with the appearance of a 73,000 MW proteinase/inhibitor complex together with a series of higher (greater than 100,000) MW complexes. IMCP was not dissociated from these complexes when electrophoresed under reducing conditions, although prior heat treatment of mouse serum (60 for 30-160 min) abolished the formation of all proteinase/inhibitor complexes. Similarly, the activity of a 48,000 MW inhibitor of chymotrypsin was abolished by heat treatment. A titration experiment established that between 0.5 and 5 mg IMCP were inhibited per ml of serum. The properties and MW of the IMCP inhibitor complexes are typical of serpins and suggest that IMCP secreted during intestinal immunological reactions would be rapidly and irreversibly inactivated by plasma-derived inhibitors.

  7. Measurement and prediction of aromatic solute distribution coefficients for aqueous-organic solvent systems. Final report

    Campbell, J.R.; Luthy, R.G.


    Experimental and modeling activities were performed to assess techniques for measurement and prediction of distribution coefficients for aromatic solutes between water and immiscible organic solvents. Experiments were performed to measure distribution coefficients in both clean water and wastewater systems, and to assess treatment of a wastewater by solvent extraction. The theoretical portions of this investigation were directed towards development of techniques for prediction of solute-solvent/water distribution coefficients. Experiments were performed to assess treatment of a phenolic-laden coal conversion wastewater by solvent extraction. The results showed that solvent extraction for recovery of phenolic material offered several wastewater processing advantages. Distribution coefficients were measured in clean water and wastewater systems for aromatic solutes of varying functionality with different solvent types. It was found that distribution coefficients for these compounds in clean water systems were not statistically different from distribution coefficients determined in a complex coal conversion process wastewater. These and other aromatic solute distribution coefficient data were employed for evaluation of modeling techniques for prediction of solute-solvent/water distribution coefficients. Eight solvents were selected in order to represent various chemical classes: toluene and benzene (aromatics), hexane and heptane (alkanes), n-octanol (alcohols), n-butyl acetate (esters), diisopropyl ether (ethers), and methylisobutyl ketone (ketones). The aromatic solutes included: nonpolar compounds such as benzene, toluene and naphthalene, phenolic compounds such as phenol, cresol and catechol, nitrogenous aromatics such as aniline, pyridine and aminonaphthalene, and other aromatic solutes such as naphthol, quinolinol and halogenated compounds. 100 references, 20 figures, 34 tables.

  8. Isolation, Identification, and Characterisation of Degradation Products and the Development and Validation of a Stability-Indicating Method for the Estimation of Impurities in the Tolterodine Tartrate Formulation.

    Prakash, Lakkireddy; Himaja, Malipeddi; Vasudev, Rudraraju


    A short and sensitive stability-indicating gradient RP-UPLC method was developed for the quantitative determination of process-related impurities and degradation products of tolterodine tartrate in pharmaceutical formulations. The method was developed by using the Waters ACQUITY UPLC™ BEH shield RP18 (2.1 × 100 mm, 1.7 μm) column with a mobile phase containing a gradient mixture of solvent A and B at a detection wavelength of 210 nm. During the stress study, the degradation products of tolterodine tartrate were well-resolved from tolterodine and its impurities and the mass balances were found to be satisfactory in all the stress conditions, thus proving the stability-indicating capability of the method. The developed method was validated as per ICH guidelines with respect to specificity, linearity, limit of detection and quantification, accuracy, precision, ruggedness, and robustness. During the stability (40°C/75% RH, 3 months) analysis of the drug product, one unknown impurity was detected by the above stability-indicating method. The unknown impurity was isolated by preparative HPLC and subjected to mass and NMR studies. Based on the spectral data, the unknown impurity was characterised as 2-(3-amino-1-phenylpropyl)-4-methylphenol (des-N,N-diisopropyl tolterodine). Structural elucidation of the impurity by spectral data is discussed in detail.

  9. Effect of a Ti capping layer on thermal stability of NiSi formed from Ni thin films deposited by metal-organic chemical vapor deposition using a Ni(iPr-DAD)2 precursor

    Park, Jingyu; Jeon, Heeyoung; Kim, Hyunjung; Jang, Woochool; Kang, Chunho; Yuh, Junhan; Jeon, Hyeongtag


    Ni films were deposited by metal-organic chemical vapor deposition (MOCVD) using a novel Ni precursor, bis(1,4-di-isopropyl-1,3-diazabutadienyl)nickel [Ni(iPr-DAD)2], and NH3 gas. To optimize process conditions, the deposition temperature and reactant partial pressure were varied from 200 to 350 °C and from 0.2 to 0.99 Torr, respectively. Ni films deposited at 300 °C with a reactant pressure of 0.8 Torr exhibited excellent quality, and had a low carbon impurity concentration of around 4%. In addition, a sacrificial Ti capping layer was deposited by an in situ e-beam evaporator on top of the Ni films to enhance the thermal stability of the subsequently formed NiSi films. Both the Ti-capped and uncapped Ni films were annealed by a two-step method, with a first annealing conducted at 500 °C, followed by wet etching and then a second annealing carried out from 500 to 900 °C. The Ti capping layer did not affect the silicidation kinetic process, but by acting as an oxygen scavenger, it did enhance the morphological stability of the NiSi films and thus improve their electrical properties.

  10. Polymeric Structure and Solid NMR Spectra of Cadmuim ( Ⅱ)Dialkyldithiophosphates(Alkyl=Propyl,Butyl,Isopropyl and Isobutyl)

    尹业高; WILLIS; ,Forsling; 等


    By dropwise adding thio ligands to concentrated aqueous solutions of Cd(ClO4)2·6H2O ,polymeric complexes,Cd(Ⅱ)O,O′-dipropyldithiophosphate(1),O,O′-dibutyl-dithiophosphate(2),O,O′-diisopropyl-dithiophosphate(3) and O,O′-diisobutyl-dithiophos phate(4) were obtained.The structure of 4 was determined by Xray diffraction analysis,showing that the metal ion sits in distorted tetrahedral sulphur coordination sphere and that the eight-memberd bimetallic rings take the twist chair and boat conformations, alternately.Based on facts that the S(1)-Cd Bond length [0.25099(12)nm] is shorter than the other S-Cd bond length [0.25399(12)-0.25701(18)nm] and that the S(1)-involving angles [113.45(4)°-118.43(5)°] are systematically large than the normal angles of a tetrahedron,the ligands are hypothesized to be erratically functionalized to Cd(Ⅱ).To certify the steric nonequivalence of ligands,the compounds were investigated by solid 13C,31P and 113Cd NMR spectroscopy.

  11. Evaluation of bile reflux in HIDA images based on fluid mechanics.

    Lo, Rong-Chin; Huang, Wen-Lin; Fan, Yu-Ming


    We propose a new method to help physicians assess, using a hepatobiliary iminodiacetic acid scan image, whether or not there is bile reflux into the stomach. The degree of bile reflux is an important index for clinical diagnosis of stomach diseases. The proposed method applies image-processing technology combined with a hydrodynamic model to determine the extent of bile reflux or whether the duodenum is also folded above the stomach. This condition in 2D dynamic images suggests that bile refluxes into the stomach, when endoscopy shows no bile reflux. In this study, we used optical flow to analyze images from Tc99m-diisopropyl iminodiacetic acid cholescintigraphy (Tc99m-DISIDA) to ascertain the direction and velocity of bile passing through the pylorus. In clinical diagnoses, single photon emission computed tomography (SPECT) is the main clinical tool for evaluating functional images of hepatobiliary metabolism. Computed tomography (CT) shows anatomical images of the external contours of the stomach, liver, and biliary extent. By exploiting the functional fusion of the two kinds of medical image, physicians can obtain a more accurate diagnosis. We accordingly reconstructed 3D images from SPECT and CT to help physicians choose which cross sections to fuse with software and to help them more accurately diagnose the extent and quantity of bile reflux.

  12. Regulated pH-Responsive Polymeric Micelles for Doxorubicin Delivery to the Nucleus of Liver Cancer Cells.

    Li, Hao; Li, Xian; Zhang, Chao; Sun, Qiquan; Yi, Wei; Wang, Xuan; Cheng, Du; Chen, Shupeng; Liang, Biling; Shuai, Xintao


    A diblock copolymer of poly(ethylene glycol) (PEG) and poly(γ-benzyl L-glutamate) (PBLG), PEG-PBLG, was synthesized via the ring-opening polymerization of γ-benzyl L-glutamate N-carboxyanhydride (BLG-NCA) using allyl-PEG-NH2 as a macroinitiator. After deprotection of the benzyl groups, N,N-diisopropyl ethylenediamine (DIP) was conjugated to poly(L-glutamic acid) (PGA) blocks as side groups. The pendant DIP groups on the PGA blocks greatly enhance the pH-sensitivity of poly(ethylene glycol)-block-poly[N-(N',N'-diisopropylaminoethyl) glutamide] [PEG-PGA(DIP)] micelles, and a higher grafting percentage of DIP favors a faster acid-response. In neutral aqueous solution, the PEG-PGA(DIP) can self-assemble into stable micelles featuring an acid-responsive PGA(DIP) core with the encapsulated anticancer drug doxorubicin (DOX). In an acidic environment, the hydrophobic-hydrophilic transition of the PGA block leads to the gradual expansion and disassembly of these micelles and, consequently, an accelerated release of DOX. Thus, DOX transported by PEG-PGA(DIP) micelles can be entrapped more efficiently into the nuclei of hepatoma Bel 7402 cells.

  13. Research and development for solar thermal energy system. Research on advanced solar component; Taiyonetsu energy system no kenkyu kaihatsu. Kiki no kenkyu

    Tanaka, T.; Doi, T.; Takashima, T.; Ando, Y.; Masuda, T.; Fujii, T. [Electrotechnical Laboratory, Tsukuba (Japan)


    Described herein are the results of the FY1994 research program for research on advanced solar components as part of research and development of solar thermal energy. The catalyst for liquid-film reactions is prepared, and the flask tests are conducted as the preliminary experiments for development of the reactor in which 2-propanol is fallen in liquid film over the catalyst dispersed to accelerate its decomposition. It is decomposable when fallen in liquid film even in the presence of 35% of acetone. The catalyst of ruthenium carried by activated coal is used to produce 2-propanol under an exothermic condition from acetone and hydrogen. Diisopropyl ether and 4-methyl-2-pentanone are produced as by-products, when the reactor tube is kept at 140 to 200{degree}C at the external wall, diminishing as temperature is increased. There is a temperature differential of 20 to 30{degree}C in the reactor tube between the center axis and external wall. 3 figs.

  14. Immediate post-dosing paralysis following severe soman and VX toxicosis in guinea pigs.

    Bide, R W; Schofield, L; Risk, D J


    There have been numerous studies of the central nervous system (CNS) involvement in organophosphate (OP) poisoning showing status epilepticus and/or 'electrographic seizures'. Brain damage has been demonstrated as 'neuronal necrosis' primarily in the cortex, thalamus and hippocampus. To the authors' knowledge there have been no reports of partial/total paralysis following close upon OP exposure although delayed paralysis has been reported. This report summarizes the immediate, OP induced paralytic events recorded in guinea pigs during development of the Canadian reactive skin decontaminant lotion (RSDL). As part of the development work, supra-lethal cutaneous doses of OP were applied to large numbers of guinea pigs followed by decontamination with the RSDL or predecessor lotions and solvents. Soman (pinacolyl methylphosphonofluoridate; GD) challenges were applied to 1277 animals and S-(2-diisopropyl-aminoethyl) methylphosphorothiolate (VX) challenges to 108. The classic sequence of clinical signs--ptyalism, tremors, fasciculations, convulsions, apnea and flaccid paralysis before death--was seen in the 658 animals that died and in many of the survivors. Eighty-four of 688 survivors of GD and 4 of 39 survivors of VX showed random paralysis of various distal regions following recovery from an insult which produced convulsions and/or flaccid paralysis. Because the experiments were designed to assess the decontamination procedures, there were no apparent relationships between the amounts of OP applied and the sequellae recorded. The observations of paralysis were also incidental to the prime focus of the experiments. Because of this, only ten animals paralysed following GD exposure were examined for histological effects. The pathologist diagnosed 'encephalomalacia' and 'focal necrotic lesions' in the cerebral cortex and 'focal necrotic lesions' in one spinal cord. Of the 84 guinea pigs paralysed after GD challenge, one was not decontaminated and the decontaminants used

  15. Potentiating Action of Propofol at GABAA Receptors of Retinal Bipolar Cells

    Yue, Lan; Xie, An; Bruzik, Karol S.; Frølund, Bente; Qian, Haohua


    Purpose. Propofol (2,6-diisopropyl phenol), a widely used systemic anesthetic, is known to potentiate GABAA receptor activity in a number of CNS neurons and to produce changes in electroretinographically recorded responses of the retina. However, little is known about propofol's effects on specific retinal neurons. The authors investigated the action of propofol on GABA-elicited membrane current responses of retinal bipolar cells, which have both GABAA and GABAC receptors. Methods. Single, enzymatically dissociated bipolar cells obtained from rat retina were treated with propofol delivered by brief application in combination with GABA or other pharmacologic agents or as a component of the superfusing medium. Results. When applied with GABA at subsaturating concentrations and with TPMPA (a known GABAC antagonist), propofol markedly increased the peak amplitude and altered the kinetics of the response. Propofol increased the response elicited by THIP (a GABAA-selective agonist), and the response was reduced by bicuculline (a GABAA antagonist). The response to 5-methyl I4AA, a GABAC-selective agonist, was not enhanced by propofol. Serial brief applications of (GABA + TPMPA + propofol) led to a progressive increase in peak response amplitude and, at higher propofol concentrations, additional changes that included a prolonged time course of response recovery. Pre-exposure of the cell to perfusing propofol typically enhanced the rate of development of potentiation produced by (GABA + TPMPA + propofol) applications. Conclusions. Propofol exerts a marked and selective potentiation on GABAA receptors of retinal bipolar cells. The data encourage the use of propofol in future studies of bipolar cell function. PMID:21071744

  16. Aromatic ring strain in arylselenenyl bromides: role in facile synthesis of selenenate esters via intramolecular cyclization.

    Selvakumar, K; Singh, Harkesh B; Butcher, Ray J


    The synthesis and reactivity of 2,6-disubstituted arylselenium compounds derived from 2-bromo-5-tert-butylisophthalic acid (43) are described. The syntheses of bis(5-tert-butylisophthalic acid dimethyl ester)diselenide (46) and bis(5-tert-butylisophthalic acid diisopropyl ester)diselenide (47) have been achieved by the reaction of the corresponding ester precursors with disodium diselenide. Reduction of diselenide 46 with lithium aluminum hydride affords 2,2'-bis(5-tert-butylbenzene-1,3-dimethanol)diselenide (53). Diselenides 46 and 47 exhibit intramolecular Se...O interaction. Compound 53 does not show any intramolecular Se...O interaction. The anomalous Se...O nonbonded coordination observed in the single-crystal X-ray structures of compounds 46, 47 and 53 is compared and contrasted. The corresponding selenenyl bromides 54 and 55, derived from the reaction of diselenides 46 and 47 with bromine, are quite stable in the solid state. However, they undergo hydrolysis and subsequent intramolecular cyclization upon heating or after having been kept in solution over a period of time to give the corresponding selenenate esters 56 and 57. The X-ray crystallographic study and density functional theory calculations on 54 at the B3LYP/6-31G(d) level of theory indicate a significant distortion in planarity of the aromatic ring. Glutathione peroxidase-like activities of diselenides 46 and 47 and their selenenate esters 56 and 57 have been studied both by thiophenol and bioassay methods. The very low glutathione peroxidase-like activity of the diselenides (46 and 47) and their selenenate esters (56 and 57) in the thiophenol assay is attributed to the presence of the relatively strong Se...O intramolecular interaction in the selenenyl sulfide intermediates. The interaction retards the catalytic activity through both thiol exchange and an intramolecular cyclization reaction.

  17. Lipase-catalyzed methanolysis of triricinolein in organic solvent to produce 1,2(2,3)-diricinolein.

    Turner, Charlotta; He, Xiaohua; Nguyen, Tasha; Lin, Jiann-Tsyh; Wong, Rosalind Y; Lundin, Robert E; Harden, Leslie; McKeon, Thomas


    The objective of this study was to find the optimal parameters for lipase-catalyzed methanolysis of triricinolein to produce 1,2(2,3)-diricinolein. Four different immobilized lipases were tested, Candida antarctica type B (CALB), Rhizomucor miehei (RML), Pseudomonas cepacia (PCL), and Penicillium roquefortii (PRL). n-Hexane and diisopropyl ether (DIPE) were examined as reaction media at three different water activities (a(w)), 0.11, 0.53, and 0.97. The consumption of triricinolein and the formation of 1,2(2,3)-diricinolein, methyl ricinoleate, and ricinoleic acid were followed for up to 48 h. PRL gave the highest yield of 1,2(2,3)-diricinolein. Moreover, this lipase showed the highest specificity for the studied reaction, i.e., high selectivity for the reaction with triricinolein but low for 1,2(2,3)-diricinolein. Recoveries of 93 and 88% DAG were obtained using PRL in DIPE at a(w) of 0.11 and 0.53, respectively. Further, NMR studies showed that a higher purity of the 1,2(2,3)-isomer vs. the 1,3-isomer was achieved at higher a(w) (88% at a(w) = 0.53), compared to lower a(w) (71% at a(w) = 0.11). The DAG obtained was acylated by the DAG acyltransferase from Arabidopsis thaliana. Therefore, this enzymatic product is a useful enzyme substrate for lipid biosynthesis. Accordingly, the use of PRL in DIPE at a(w) 0.53 is considered optimal for the synthesis of 1,2(2,3)-diricinolein from triricinolein.

  18. Synthesis and physico-chemical characterization of CeO{sub 2}/ZrO{sub 2}-SO{sub 4}{sup 2-} mixed oxides

    Hernandez E, J. M.; Silva R, R.; Garcia A, R. [Instituto Tecnologico de Ciudad Madero, Div. de Estudios de Posgrado e Investigacion, Juventino Rosas y Jesus Urueta s/n, Col. Los Mangos, 89440 Ciudad Madero, Tamaulipas (Mexico); Garcia S, L. A. [IPN, Centro Interdisciplinario de Investigaciones y de Estudios sobre Medio Ambiente y Desarrollo, 30 de Junio No. 1520, Barrio La Laguna Ticoman, 07340 Mexico D. F. (Mexico); Handy, B. E.; Cardenas G, G. [Universidad Autonoma de San Luis Potosi, CIEP, Facultad de Ciencias Quimicas, Av. Dr. Manuel Nava No. 6, Zona Universitaria, 78210 SLP, San Luis Potosi (Mexico); Cueto H, A. [Universidad Autonoma Metropolitana, Unidad Azcapotzalco, Av. San Pablo No. 180, Col. Reynosa Tamaulipas, 02200 Mexico D. F. (Mexico)


    Environmentally friendly solid-acid catalysts CeO{sub 2}/ZrO{sub 2}-SO{sub 4}{sup 2-} were prepared by the sol gel method varying CeO{sub 2} content (10, 20 and 30 wt %) and using sulfation in situ, maintaining the sulfate ions amount present in the materials at 20 wt %. ZrO{sub 2} and ZrO{sub 2}-SO{sub 4}{sup 2-} were also prepared for comparison proposes using the same synthesis method. The materials were characterized by X-ray diffraction, nitrogen physisorption, potentiometric titration with n-butylamine, decomposition of 2-propanol and n-pentane isomerization. The specific surface area of ZrO{sub 2}-SO{sub 4}{sup 2-} was high (160 m{sup 2}/g) compared with the unmodified ZrO{sub 2} (80 m{sup 2}/g), however this area decreased with increasing the CeO{sub 2} content (37-100 m{sup 2}/g). There was no significant effect of CeO{sub 2} on the tetragonal structure of ZrO{sub 2}-SO{sub 4}{sup 2-}. The variation of acid sites amount runs parallel to the change of specific surface area. The acid sites amount decreased with increasing cerium oxide content. The decomposition of 2-propanol results fundamentally in the formation of dehydration products such as propylene and diisopropyl ether, both involving acid sites. In addition, a good performance during the n-pentane isomerization was observed for these materials. The selectivity towards isopentane reaches 84% when the Pt/CeO{sub 2}/ZrO{sub 2}-SO{sub 4}{sup 2-} catalyst with the highest CeO{sub 2} content was used. (Author)

  19. Properties Of A Midgut Trypanolysin From The Tsetse Fly Glossina Morsitans Morsitans

    Mahamat H.Abakar


    Full Text Available The properties of a bloodmeal-induced trypanolysin from the midgut of the tsetse G. m. morsitans was studied in vitro. The semi-purified trypanolysin from twice-fed tsetse had the highest trypanolysin activity against bloodstream trypanosomes followed by those once-fed and the unfed flies. Serum found to display trypanolysin activity. The trypanolysin had no trypsin activity nor even affected by the enzyme. In addition trypanolysin was not affected by protease inhibitors such as soy bean trypsin inhibitor STI N-a-p-Tosyl-L-lysine chromethyl ketone TLCK phenylmethyl sulphonyl fluoride PMSF diisopropyl fluoro-phosphate DFP and tosylamide-2-phenylethyl chloromethyl ketone TPCK. However the activity was completely inhibited by diethyl pyrocarbonate DEPC and partially by aprotinin. The induction of trypanolysin activity by bloodmeal increased gradually reaching a peak at 72-120 h after the bloodmeal and then decreased rapidly with only 25 of the peak activity remaining after 192 h. The trypanolysin was inactivated during storage at 27amp8451 and 4amp8451 after 15 and 32 days respectively. Similarly heating the midguts trypanolysin to 60 - 80amp8451 led to loss of activity. On the other hand 50amp8451 was found to be the optimum temperature for trypanolysin activity. The activity was also unstable by freeze-thaw at 80amp8451 -70amp8451 -20amp8451 and 0amp8451 after 33 41 55 and 63 days respectively. Trypanolysin caused lyses of bloodstream-form T. b. brucei while the procyclic trypanosomes were unaffected. The highest trypanolysin activity in different tsetse species was found with Glossina longipennis followed by Glossina pallidipes Glossina morsitans centralis Glossina fuscipes fuscipes and G. m. morsitans. When the midgut homogenate was separated by anion-exchange chromatography the trypanolysin activity was recovered in the bound fraction. These results suggest that the midgut trypanolysin plays an important role in the establishment of

  20. An automated flow system incorporating in-line acid dissolution of bismuth metal from a cyclotron irradiated target assembly for use in the isolation of astatine-211

    O’Hara, Matthew J.; Krzysko, Anthony J.; Niver, Cynthia M.; Morrison, Samuel S.; Owsley, Stanley L.; Hamlin, Donald K.; Dorman, Eric F.; Scott Wilbur, D.


    Astatine-211 (211At) is a promising cyclotron-produced radionuclide being investigated for use in targeted alpha therapy of blood borne and metastatic cancers, as well as treatment of tumor remnants after surgical resections. The isolation of trace quantities of 211At, produced within several grams of a Bi metal cyclotron target, involves a complex, multi-step procedure: (1) Bi metal dissolution in strong HNO3, (2) distillation of the HNO3 to yield Bi salts containing 211At, (3) dissolution of the salts in strong HCl, (4) solvent extraction of 211At from bismuth salts with diisopropyl ether (DIPE), and (5) back-extraction of 211At from DIPE into NaOH, leading to a purified 211At product. Step (1) has been addressed first to begin the process of automating the onerous 211At isolation process. A computer-controlled Bi target dissolution system has been designed. The system performs in-line dissolution of Bi metal from the target assembly using an enclosed target dissolution block, routing the resulting solubilized 211At/Bi mixture to the subsequent process step. The primary parameters involved in Bi metal solubilization (HNO3 concentration and influent flow rate) were optimized prior to evaluation of the system performance on replicate cyclotron irradiated targets. The results indicate that the system performs reproducibly, having nearly quantitative release of 211At from irradiated targets, with cumulative 211At recoveries that follow a sigmoidal function. The predictable nature of the 211At release profile allows the user to tune the system to meet target processing requirements.

  1. Effects of the agrochemicals butachlor, pretilachlor and isoprothiolane on rat liver xenobiotic-metabolizing enzymes.

    Ishizuka, M; Iwata, H; Kazusaka, A; Hatakeyama, S; Fujita, S


    1. The herbicides butachlor (2-chloro-2',6',diethyl-N-[buthoxymethyl] acetanilide) and pretilachlor (2-chloro-2',6'-diethyl-N-[2-propoxyethyl] acetanilide) are widely used in Asia, South America, Europe and Africa. Isoprothiolane (diisopropyl-1,3-dithiolan-2-ylidenemalonate) is used as a fungicide and an insecticide in rice paddies. We administered these agrochemicals to the male rat and examined their effects on cytochrome P450 (P450), glutathione S-transferase (GST), UDP-glucuronosyltransferase (UDPGT), and NAD(P)H-quinone oxidoreductase 1 (NQO1)-related metabolism in the liver. 2. Administration of isoprothiolane, butachlor or pretilachlor to rat induced hepatic P4502B subfamily-dependent enzyme activities (pentoxyresorufin O-depentylation and testosterone 16 beta-hydroxylation) up to 271-413% of control, which coincided with the increase in expression levels of the P4502B apoprotein. 3. Activities of GST toward 1-chloro-2,4-nitrobenzene and 3,4-dichloronitrobenzene were slightly induced (127-133% of control) in the liver of the rat treated with these pesticides. On the other hand, marked elevations of UDPGT activities toward p-nitrophenol (164-281% of control) were observed. NQO1-related metabolism (menadione reductase activity) was also induced (123-176% of control) in the liver of rat treated with these agrochemicals. 4. These results indicate that some of the agrochemicals currently in use are capable of inducing phase I and II xenobiotic-metabolizing enzyme activities in an isozyme selective manner. The induction of these activities may disrupt normal physiologic functions related to these enzymes in exposed animals.

  2. Solid-state structure and solution conformation of the nootropic agent N[2-( N,N-Diisopropylamino)ethyl]-2-oxo-1-pyrrolidinacetamide sulphate. X-ray and homonuclear two-dimensional 1H NMR studies

    Bandoli, Giuliano; Nicolini, Marino; Pappalardo, Giuseppe C.; Grassi, Antonio; Perly, Bruno


    The crystal and molecular structure of the nootropic agent N-[2-( N,N-diisopropyl-amino)ethyl]-2-oxo-1-pyrrolidinacetamide sulphate was determined by X-ray analysis. The conformational properties in the solution state were deduced from the 1H-NMR spectrum run in 2H 2O at 500 MHz. Spectral assignments were made with the aid of the COSY 45 shift correlation experiment. Crystals were triclinic with unit cell dimensions a = 13.410(10), b = 11.382(8), c = 6.697(4) », α = 83.80(3), β = 88.61(3)and γ = 72.25(6)° ; space group Poverline1. The structure was determined from 1047 three-dimensional counter data and refined to a value of 7.5% for the conventional discrepancy factor R. One molecule of the solvent acetonitrile is incorporated per two of the (C 14H 28N 3O 2) +-(HSO 4) -. The five-membered heterocyclic ring is in an envelope ( Cs) conformation and the "flap" atom deviates by 0.31 » from the plane of the other four. This plane forms a dihedral angle of 71.4° with the amide group, with the CO fragment directed toward the ring. All bond angles and distances are in good agreement with expected standard values. A strong OH⋯O intermolecular bond (2.61 ») links the cation of the hydrogen-sulphate anion, while the loosely held MeCN molecule is trapped in the polar pockets. The molecular conformation in the solid was compared with results from 1H NMR spectral analysis which showed that in solution wide torsional oscillations can occur about the bonds of the chain bonded to the N(1) atom.

  3. Specificity of an extracellular proteinase from Conidiobolus coronatus and its inhibition by an inhibitor from insect hemolymph.

    Bania, Jacek; Samborski, Jaroslaw; Bogus, Mieczyslawa; Polanowski, Antoni


    The relatively little-investigated entomopathogen Conidiobolus coronatus secretes several proteinases into culture broth. Using a combination of ion-exchange and size-exclusion chromatography, we purified to homogeneity a serine proteinase of Mr 30,000-32,000, as ascertained by SDS-PAGE. The purified enzyme showed subtilisin-like activity. It very effectively hydrolyzed N-Suc-Ala(2)-Pro-Phe-pNa with a Km-1.36 x 10(-4) M and Kcat-24 s(-1), and N-Suc-Ala(2)-Pro-Leu-pNa with Km-6.65 x 10(-4) M and Kcat-11 s(-1). The specificity index k(cat)/K(m) for the tested substrates was calculated to be 176,340 s(-1) M(-1) and 17,030 s(-1) M(-1), respectively. Using oxidized insulin B chain as a substrate, the purified proteinase exhibited specificity to aromatic and hydrophobic amino-acid residues, such as Phe, Leu, and Gly at the P1 position, splitting primarily the peptide bonds: Phe(1)-Val(2), Leu(15)-Tyr(16), and Gly(23)-Phe(24). The proteinase appeared to be sensitive to the specific synthetic inhibitors of the serine proteinases DFP (diisopropyl flourophosphate) and PMSF (phenyl-methylsulfonyl fluoride) as well as to some naturally occurring protein inhibitors of chymotrypsin. It is worth noting that the enzyme exhibited the highest sensitivity to inhibition by AMCI-1 (with an association constant of 3 x 10(10) M(-1)), an inhibitor of cathepsin G/chymotrypsin from the larval hemolymph of Apis mellifera, reinforcing the possibility of involvement of inhibitors from hemolymph in insect innate immunity. The substrate specificity and proteinase inhibitor effects indicate that the purified proteinase from the fermentation broth of Conidiobolus coronatus is a subtilisin-like serine proteinase.

  4. Effects of acetylcholinesterase gene silencing on its activity in cultured human skeletal muscle.

    Mis, Katarina; Mars, Tomaz; Golicnik, Marko; Jevsek, Marko; Grubic, Zoran


    In spite of several reports demonstrating that acetylcholinesterase (AChE [EC]) expression is importantly regulated at the level of its mRNA, we still know little about the relationship between AChE mRNA level and the level of mature, catalytically active enzyme in the cell. Better insight into this relationship is, however, essential for our understanding of the molecular pathways underlying AChE synthesis in living cells. We have approached this problem previously (Grubic et al., 1995; Brank et al., 1998; Mis et al., 2003; Jevsek et al., 2004); however, recently introduced small interfering RNA (siRNA) methodology, which allows blockade of gene expression at the mRNA level, opens new possibilities in approaching the AChE mRNA-AChE activity relationship. With this technique one can eliminate AChE mRNA in the cell, specifically and at selected times, and follow the effects of such treatment at the mature enzyme level. In this study we followed AChE activity in siRNA-treated cultured human myoblasts. Our aim was to find out how the temporal profile of the AChE mRNA decrease is reflected at the level of AChE activity under normal conditions and after inhibition of preexisting AChE by diisopropyl phosphorofluoridate (DFP).AChE activity was determined at selected time intervals after siRNA treatment in both myoblast homogenates and in culture medium to follow the effects of siRNA treatment at the level of intracellular AChE synthesis and at the level of AChE secreted from the cell.

  5. A fluorosurfactant and photoreducible Cu(II)-tren click catalyst: surfactant and catalytic properties at liquid/liquid interfaces.

    Jochyms, Quentin; Guillot, Pierre; Mignard, Emmanuel; Vincent, Jean-Marc


    The fluorous copper(ii) complex [Cu(II)(trenRf6)3-benzoylbenzoate]3-benzoylbenzoate 2, composed of a highly fluorophilic tris(2-aminoethyl)amine ligand and two 3-benzoylbenzoates as counterions and photosensitizers, was synthesized from the dinuclear complex [Cu(3-benzoylbenzoate)4(H2O)2] 1 which was characterized by X-ray analysis. Complex 2, which is highly soluble in perfluorocarbons, moderately soluble in organic solvents while insoluble in water, was found to be a very effective fluorosurfactant. At the air/water interface it formed a Langmuir film, which upon compression slowly collapsed at about 28 mN m(-1), which corresponds to a surface area of about 220 Å(2) per molecule. Tensiometric measurements revealed that 2 is more rapidly adsorbed at the diisopropyl ether (DIPE)/water interface than the perfluorodecalin (PFD)/water one, leading to a decrease of the interfacial tensions of about 14 mN m(-1) and 40 mN m(-1), respectively. Photoreduction of 2 occurs effectively in H-donating solvents such as THF and DIPE, or even in PFD ensuring that an electron donor, such as propargyl alcohol, is present in a separate aqueous phase. Complex 2, when combined with light (365 nm), catalyzes the click reaction between the azide 3 and alkyne 4 under homogeneous conditions (methanol), to afford the disaccharide 5. Under emulsified biphasic DIPE/water or PFD/water conditions, the reactions proceeded well. However, it was shown that a fast and significant amount of copper and 3-benzoylbenzoate counterion was transferred into the aqueous phase, and that most of the catalysis could be ascribed to a copper species solubilised in the aqueous phase, and not to the fluorous copper complex accumulated at the interface.

  6. Manduca sexta hemolymph proteinase 21 activates prophenoloxidase-activating proteinase 3 in an insect innate immune response proteinase cascade.

    Gorman, Maureen J; Wang, Yang; Jiang, Haobo; Kanost, Michael R


    Melanization, an insect immune response, requires a set of hemolymph proteins including pathogen recognition proteins that initiate the response, a cascade of mostly unknown serine proteinases, and phenoloxidase. Until now, only initial and final proteinases in the pathways have been conclusively identified. Four such proteinases have been purified from the larval hemolymph of Manduca sexta: hemolymph proteinase 14 (HP14), which autoactivates in the presence of microbial surface components, and three prophenoloxidase-activating proteinases (PAP1-3). In this study, we have used two complementary approaches to identify a serine proteinase that activates proPAP3. Partial purification from hemolymph of an activator of proPAP3 resulted in an active fraction with two abundant polypeptides of approximately 32 and approximately 37 kDa. Labeling of these polypeptides with a serine proteinase inhibitor, diisopropyl fluorophosphate, indicated that they were active serine proteinases. N-terminal sequencing revealed that both were cleaved forms of the previously identified hemolymph serine proteinase, HP21. Surprisingly, cleavage of proHP21 had occurred not at the predicted activation site but more N-terminal to it. In vitro reactions carried out with purified HP14 (which activates proHP21), proHP21, proPAP3, and site-directed mutant forms of the latter two proteinases confirmed that HP21 activates proPAP3 by limited proteolysis. Like the HP21 products purified from hemolymph, HP21 that was activated by HP14 in the in vitro reactions was not cleaved at its predicted activation site.

  7. Evaluation of the impact of fuel hydrocarbons and oxygenates on groundwater resources.

    Shih, Tom; Rong, Yue; Harmon, Thomas; Suffet, Mel


    The environmental behavior of fuel oxygenates (other than methyl tert-butyl ether [MTBE]) is poorly understood because few data have been systematically collected and analyzed. This study evaluated the potential for groundwater resource contamination by fuel hydrocarbons (FHCs) and oxygenates (e.g., tert-butyl alcohol [TBA], tertamyl methyl ether [TAME], diisopropyl ether [DIPE], ethyl tert-butyl ether [ETBE], and MTBE) by examining their occurrence, distribution, and spatial extent in groundwater beneath leaking underground fuel tank (LUFT) facilities, focusing on data collected from over 7200 monitoring wells in 868 LUFT sites from the greater Los Angeles, CA, region. Excluding the composite measure total petroleum hydrocarbons as gasoline (TPHG), TBA has the greatestsite maximum (geometric mean) groundwater concentration among the study analytes; therefore, its presence needs to be confirmed at LUFT sites so that specific cleanup strategies can be developed. The alternative ether oxygenates (DIPE, TAME, and ETBE) are less likely to be detected in groundwater beneath LUFT facilities in the area of California studied and when detected are present at lower dissolved concentrations than MTBE, benzene, or TBA. Groundwater plume length was used as an initial indicator of the threat of contamination to drinking water resources. Approximately 500 LUFT sites were randomly selected and analyzed. The results demonstrate MTBE to pose the greatest problem, followed by TBA and benzene. The alternative ether oxygenates were relatively localized and indicated lesser potential for groundwater resource contamination. However, all indications suggest the alternative ether oxygenates would pose groundwater contamination threats similar to MTBE if their scale of usage is expanded. Plume length data suggest that in the absence of a completely new design and construction of the underground storage tank (UST) system, an effective management strategy may involve placing greater emphasis

  8. Rapid degradation of D- and L-succinimide-containing peptides by a post-proline endopeptidase from human erythrocytes

    Momand, J.; Clarke, S.


    The authors have been interested in the metabolic fate of proteins containing aspartyl succinimide (Asu) residues. These residues can be derived from the spontaneous rearrangement of Asp and Asn residues and from the spontaneous demethylation of enzymatically methylated L-isoAsp and D-Asp residues. Incubation of the synthetic hexapeptide N-Ac-Val-Tyr-Pro-Asu-Gly-Ala with the cytosolic fraction of human erythrocytes resulted in rapid cleavage of the prolyl-aspartyl succinimide bond producing the tripeptide N-Ac-Val-Try-Pro. The rate of this reaction is equal for both L- and D-Asu-containing peptides and is 10-fold greater that the rate of cleavage of a corresponding peptide containing a normal Pro-Asp linkage. When the aspartyl succinimide ring was replaced with an isoaspartyl residue, the cleavage rate was about 5 times that of the normal Pro-Asp peptide. The tripeptide-producing activity copurified on DEAE-cellulose chromatography with an activity that cleaves N-carbobenzoxy-Gly-Pro-4-methylcoumarin-7-amide, a post-proline endopeptidase substrate. These two activities were both inhibited by an antiserum to rat brain post-proline endopeptidase, and it appears that they are catalyzed by the same enzyme. This enzyme has a molecular weight of approximately 80,000 and is covalently labeled and inhibited by (/sup 3/H) diisopropyl fluorophosphate. The facile cleavage of the succinimide- and isoaspartyl-containing peptides by this post-proline endopeptidase suggests that it may play a role in the metabolism of peptides containing altered aspartyl residues.

  9. Redetermined structure of gossypol (P3 polymorph

    Muhabbat Honkeldieva


    Full Text Available An improved crystal structure of the title compound, C30H30O8 (systematic name: 1,1′,6,6′,7,7′-hexahydroxy-5,5′-diisopropyl-3,3′-dimethyl[2,2′-binaphthalene]-8,8′-dicarbaldehyde, was determined based on modern CCD data. Compared to the previous structure [Talipov et al. (1985. Khim. Prirod. Soedin. (Chem. Nat. Prod., 6, 20–24], geometrical precision has been improved (typical C—C bond-distance s.u. = 0.002 Å in the present structure compared to 0.005 Å in the previous structure and the locations of several H atoms have been corrected. The gossypol molecules are in the aldehyde tautomeric form and the dihedral angle between the naphthyl fragments is 80.42 (4°. Four intramolecular O—H...O hydrogen bonds are formed. In the crystal, inversion dimers with graph-set motif R22(20 are formed by pairs of O—H...O hydrogen bonds; another pair of O—H...O hydrogen bonds with the same graph-set motif links the dimers into [001] chains. The packing of such chains in the crystal leads to the formation of channels (diameter = 5–8 Å propagating in the [101] direction. The channels presumably contain highly disordered solvent molecules; their contribution to the scattering was removed with the SQUEEZE [Spek (2015. Acta Cryst. C71, 9–18] routine in PLATON and the stated molecular mass, density etc., do not take them into account.

  10. Development of transdermal therapeutic formulation of CNS5161, a novel NMDA receptor antagonist, by utilizing pressure-sensitive adhesives II: improved transdermal absorption and evaluation of efficacy and safety.

    Naruse, Mamoru; Ogawara, Ken-ichi; Kimura, Toshikiro; Konishi, Ryoji; Higaki, Kazutaka


    The aim of this study was to prepare a transdermal therapeutic formulation of CNS5161, an NMDA receptor antagonist developed as a drug for neuropathic pain. Since a silicone pressure-sensitive adhesive (PSA) was found to be the best PSA for CNS5161 among six different PSAs examined in our previous study, the effects of the loading concentration of CNS5161 on release and rat skin permeability were investigated using silicone PSAs. The release of CNS5161 was elevated with an increase in the drug concentration from 1% to 14%. The transdermal flux at the steady state reached a plateau at 8% and over, while crystallization of CNS5161 was not observed for any formulation even at high drug concentrations. The drug concentration in rat skin at the steady state was also saturated at 8% and over, which correlated well with the transdermal flux at the steady state. Therefore, skin permeation clearance defined to the skin concentration at the steady state was almost constant at 0.21/h from 2% to 14% of CNS5161, which suggests that drug concentrations in the skin would be a driving force for transport of the drug to the receptor side. Since increasing the concentration of CNS5161 in the PSA patch was not able to elevate the transdermal flux, 12 formulations containing several permeation enhancers were examined to improve the transdermal transport of CNS5161. Among them, the formulation containing propylene glycol, diisopropyl adipate, and polyvinylpyrrolidone significantly increased the transdermal flux by approximately 1.8-fold by improving the diffusivity of CNS5161 in the skin, and also significantly enhanced the analgesic effect of CNS5161. This formulation caused only slight skin irritation, which indicated that it would be a promising transdermal therapeutic system for CNS5161.

  11. Dust as a collection media for contaminant source attribution.

    Favela, Kristin Herrmann; Bohmann, Jonathan A; Williamson, William S


    Dust was investigated for its ability to retain source attribution profiles (SAPs) after chemical exposure. Three distinct sources of the organophosphate pesticide acephate were investigated as a proof-of-concept model. In addition, attribution profiles were created and tested using compounds related to chemical warfare agents (CWAs), specifically VX and G-series agents: O-ethyl methylphosphonothioate (EMPTA), N,N-diisopropylmethylamine (DIPMA), N,N-diisopropylethylamine (DIEA), diisopropylamine (DIPA), diethyl aniline (DEA), diethyl ethyl phosphonate (DEEP), trimethyl phosphite (TMP), dimethyl hydrogen phosphite (DMHP), diethyl hydrogen phosphite (DEHP), triethyl phosphate (TEP), ethyl methylphosphonate (EMPA), and diisopropyl methylphosphonate (DIMP). Dust was collected from a storage shed, aliquots deposited on carpet and loaded with distinct chemical profiles using an exposure chamber and aerosolizer. After a given period of time (1h, 24h, or 72 h), the dust was extracted and its SAP analyzed by gas chromatography-mass spectrometry (GC-MS) and/or liquid chromatography-tandem mass spectrometry (LC-MS/MS). Principal components analysis (PCA) was used to determine the association of dust exposed to the same and different chemical sources. PCA results demonstrate that dust samples exposed to distinct chemical sources are clearly differentiated from one another across all collection times. Furthermore, dust aliquots exposed to the same source can be clearly associated with one another across all collection times. When the CWA-related compounds were subjected to elevated temperature (90°C) conditions, it was found that the signature was stable at the 1h and 24h collections. At 72 h and elevated temperature, larger deviations from the control were observed for some compounds. Elevated pH (10) affected the profile to a lesser degree than elevated temperature. Overall, dust is found to be an effective media for the in situ collection of source attribution profiles.

  12. Health assessment of gasoline and fuel oxygenate vapors: reproductive toxicity assessment.

    Gray, Thomas M; Steup, David; Roberts, Linda G; O'Callaghan, James P; Hoffman, Gary; Schreiner, Ceinwen A; Clark, Charles R


    Vapor condensates of baseline gasoline (BGVC), or gasoline-blended with methyl tertiary butyl ether (G/MTBE), ethyl t-butyl ether (G/ETBE), t-amyl methyl ether (G/TAME), diisopropyl ether (G/DIPE), ethanol (G/EtOH), or t-butyl alcohol (G/TBA) were evaluated for reproductive toxicity in rats at target concentrations of 2000, 10,000, or 20,000mg/m(3), 6h/day, 7days/week. BGVC and G/MTBE were assessed over two generations, the others for one generation. BGVC and G/MTBE F1 offspring were evaluated for neuropathology and changes in regional brain glial fibrillary acidic protein content. No neurotoxicity was observed. Male kidney weight was increased consistent with light hydrocarbon nephropathy. In adult rats, decreased body weight gain and increased liver weight were seen. Spleen weight decreased in adults and pups exposed to G/TBA. No pathological changes to reproductive organs occurred in any study. Decreased food consumption was seen in G/TAME lactating females. Transient decreases in G/TAME offspring weights were observed during lactation. Except for a minor increase in time to mating in G/TBA which did not affect other reproductive parameters, there were no adverse reproductive findings. The NOAEL for reproductive and offspring parameters was 20,000mg/m(3) for all vapor condensates except for lower offspring NOAELs of 10,000mg/m(3) for G/TBA and 2000mg/m(3) for G/TAME.

  13. Health assessment of gasoline and fuel oxygenate vapors: immunotoxicity evaluation.

    White, Kimber L; Peachee, Vanessa L; Armstrong, Sarah R; Twerdok, Lorraine E; Clark, Charles R; Schreiner, Ceinwen A


    Female Sprague Dawley rats were exposed via inhalation to vapor condensates of either gasoline or gasoline combined with various fuel oxygenates to assess potential immunotoxicity of evaporative emissions. Test articles included vapor condensates prepared from "baseline gasoline" (BGVC), or gasoline combined with methyl tertiary butyl ether (G/MTBE), ethyl t-butyl ether (G/ETBE), t-amyl methyl ether (G/TAME), diisopropyl ether (G/DIPE), ethanol (G/EtOH), or t-butyl alcohol (G/TBA). Target concentrations were 0, 2000, 10,000 or 20,000mg/mg(3) administered for 6h/day, 5days/week for 4weeks. The antibody-forming cell (AFC) response to the T-dependent antigen, sheep erythrocyte (sRBC), was used to determine the effects of the gasoline vapor condensates on the humoral components of the immune system. Exposure to BGVC, G/MTBE, G/TAME, and G/TBA did not result in significant changes in the IgM AFC response to sRBC, when evaluated as either specific activity (AFC/10(6) spleen cells) or as total spleen activity (AFC/spleen). Exposure to G/EtOH and G/DIPE resulted in a dose-dependent decrease in the AFC response, reaching the level of statistical significance only at the high 20,000mg/m(3) level. Exposure to G/ETBE resulted in a statistically significant decrease in the AFC response at the middle (10,000mg/m(3)) and high (20,000mg/m(3)) exposure concentrations.

  14. Preparation of soluble apolipoproteins A-I, B, and C-II by a chromatofocusing column method, and evaluation of their concentrations in serum in pulmonary disease.

    Jauhiainen, M; Laitinen, M; Marniemi, J; Liippo, K; Penttilä, I; Hietanen, E


    A chromatofocusing column method for isolating ApoB is described. LDL is first isolated by sequential ultracentrifugation and delipidated with n-butanol/diisopropyl ether. Chromatofocusing of ApoLDL yielded a large ApoB peak at pI 5.0-5.3. ApoA-I and ApoC-II were prepared analogously, with HDL and VLDL as the source of apoprotein. Antisera were raised in rabbits, and electroimmunoassay techniques were used for determination. ApoB was water-soluble after chromatofocusing. Intra-assay precision (CV) was 4.7% for ApoA-I, 7.8% for ApoB in the "rocket" electrophoresis. Interassay precision (CV) was 6% for ApoA-I and 8% for ApoB. Apolipoprotein concentrations were measured in subjects who had undergone lung resection and patients with obstructive pulmonary disease. After lung resection, the concentration of ApoA-I in serum was significantly decreased (p less than 0.001) and that of ApoB significantly increased (p less than 0.001) as compared with controls. The ApoA-I/ApoB ratio was significantly lower in the lung-resection group. ApoA-I and ApoB concentrations were unchanged in chronic obstructive pulmonary disease. ApoC-II concentrations in each group were similar to those for control subjects. Of the lipids, values for total cholesterol were above normal after lung resection (p less than 0.002), as were those for triglycerides (p less than 0.02).

  15. Simultaneous determination of gasoline oxygenates and benzene, toluene, ethylbenzene and xylene in water samples using headspace-programmed temperature vaporization-fast gas chromatography-mass spectrometry.

    Pérez Pavón, José Luis; del Nogal Sánchez, Miguel; Fernández Laespada, María Esther; Moreno Cordero, Bernardo


    A sensitive method is presented for the fast analysis of seven fuel oxygenates (methanol, ethanol, tert-butyl alcohol (TBA), methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), tert-amyl methyl ether (TAME) and diisopropyl ether (DIPE)) and benzene, toluene, ethylbenzene and p-xylene (BTEX) in water samples. The applicability of a headspace (HS) autosampler in combination with a GC device equipped with a programmable temperature vaporizer (PTV) and a MS detector is explored. The proposed method achieves a clear improvement in sensitivity with respect to conventional headspace methods due to the use of the PTV. Two different packed liners with materials of different trapping strengths (glass wool and Tenax-TA) were compared. The benefits of using Tenax-TA instead of glass wool as packed material for the measurement of the 11 compounds emerged as better signal-to-noise ratios and hence better detection limits. The proposed method is extremely sensitive. The limits of detection are of the order of ng/L for six of the compounds studied and of the order of microg/L for the rest, with the exception of the most polar and volatile compound: methanol. Precision (measured as the relative standard deviation for a level with an S/N ratio close to 3) was equal to or lower than 15% in all cases. The method was applied to the determination of the analytes in natural matrixes (tap, river and sea water) and the results obtained can be considered highly satisfactory. The methodology has much lower detection limits than the concentration limits proposed in drinking water by the US Environmental Protection Agency (EPA) and the European Union for compounds under regulation.

  16. Simultaneous determination of methyl tert.-butyl ether and its degradation products, other gasoline oxygenates and benzene, toluene, ethylbenzene and xylenes in Catalonian groundwater by purge-and-trap-gas chromatography-mass spectrometry.

    Rosell, Mònica; Lacorte, Sílvia; Ginebreda, Antoni; Barceló, Damià


    In Catalonia (northeast Spain), a monitoring program was carried out to determine methyl tert.-butyl ether (MTBE), its main degradation products, tert.-butyl alcohol (TBA), tert.-butyl formate (TBF), and other gasoline additives, the oxygenate dialkyl ethers ethyl tert.-butyl ether, tert.-amyl methyl ether and diisopropyl ether and the aromatic compounds benzene, toluene, ethylbenzene and xylene (BTEX) in 21 groundwater wells that were located near different gasoline point sources (a gasoline spill and underground storage tank leakage). Purge-and-trap coupled to gas chromatography-mass spectrometry was optimised for the simultaneous determination of the above mentioned compounds and enabled to detect concentrations at ng/l or sub-microg/l concentrations. Special attention was given to the determination of polar MTBE degradation products, TBA and TBF, since not much data on method performance and environmental levels are given on these compounds in groundwater. All samples analysed contained MTBE at levels between 0.3 and 70 microg/l. Seven contaminated hot spots were identified with levels up to US Environmental Protection Agency drinking water advisory (20-40 microg/l) and a maximum concentration of 670 microg/l (doubling the Danish suggested toxicity level of 350 microg/l). Samples with high levels of MTBE contained 0.1-60 microg/l of TBA, indicating (but not proving) in situ degradation of parent compound. In all cases, BTEX was at low concentrations or not detected showing less solubility and persistence than MTBE. This fact confirms the suitability of MTBE as a tracer or indicator of long-term gasoline contamination than the historically used BTEX.

  17. Surface chemistry of group 11 atomic layer deposition precursors on silica using solid-state nuclear magnetic resonance spectroscopy

    Pallister, Peter J.; Barry, Seán T.


    The use of chemical vapour deposition (CVD) and atomic layer deposition (ALD) as thin film deposition techniques has had a major impact on a number of fields. The deposition of pure, uniform, conformal thin films requires very specific vapour-solid reactivity that is largely unknown for the majority of ALD and CVD precursors. This work examines the initial chemisorption of several thin film vapour deposition precursors on high surface area silica (HSAS) using 13C, 31P, and quantitative 29Si nuclear magnetic resonance spectroscopy (NMR). Two copper metal precursors, 1,3-diisopropyl-imidazolin-2-ylidene copper (I) hexamethyldisilazide (1) and 1,3-diethyl-imidazolin-2-ylidene copper(I) hexamethyldisilazide (2), and one gold metal precursor, trimethylphosphine gold(III) trimethyl (3), are examined. Compounds 1 and 2 were found to chemisorb at the hydroxyl surface-reactive sites to form a ||-O-Cu-NHC surface species and fully methylated silicon (||-SiMe3, due to reactivity of the hexamethyldisilazane (HMDS) ligand on the precursor) at 150 °C and 250 °C. From quantitative 29Si solid-state NMR (SS-NMR) spectroscopy measurements, it was found that HMDS preferentially reacts at geminal disilanol surface sites while the copper surface species preferentially chemisorbed to lone silanol surface species. Additionally, the overall coverage was strongly dependent on temperature, with higher overall coverage of 1 at higher temperature but lower overall coverage of 2 at higher temperature. The chemisorption of 3 was found to produce a number of interesting surface species on HSAS. Gold(III) trimethylphosphine, reduced gold phosphine, methylated phosphoxides, and graphitic carbon were all observed as surface species. The overall coverage of 3 on HSAS was only about 10% at 100 °C and, like the copper compounds, had a preference for lone silanol surface reactive sites. The overall coverage and chemisorbed surface species have implications to the overall growth rate and purity of

  18. Effects of hydroxyl-functionalization and sub-Tg thermal annealing on high pressure pure- and mixed-gas CO2/CH4 separation by polyimide membranes based on 6FDA and triptycene-containing dianhydrides

    Swaidan, Raja


    A sub-Tg thermally-annealed (250°C, 24h) ultra-microporous PIM-polyimide bearing a 9,10-diisopropyl-triptycene contortion center and hydroxyl-functionalized diamine (2,2-bis(3-amino-4-hydroxyphenyl)-hexafluoropropane, APAF) exhibited plasticization resistance up to 50bar for a 1:1 CO2/CH4 feed mixture, with a 9-fold higher CO2 permeability (30Barrer) and 2-fold increase in CO2/CH4 permselectivity (~50) over conventional dense cellulose acetate membranes at 10bar CO2 partial pressure. Interestingly, mixed-gas CO2/CH4 permselectivities were 10-20% higher than those evaluated under pure-gas conditions due to reduction of mixed-gas CH4 permeability by co-permeation of CO2. Gas transport, physisorption and fluorescence studies indicated a sieving pore-structure engaged in inter-chain charge transfer complexes (CTCs), similar to that of low-free-volume 6FDA-APAF polyimide. The isosteric heat of adsorption of CO2 as well as CO2/CH4 solubility selectivities varied negligibly upon replacement of OH with CH3 but CTC formation was hindered, CO2 sorption increased, CO2 permeability increased ~3-fold, CO2/CH4 permselectivity dropped to ~30 and CH4 mixed-gas co-permeation increased. These results suggest that hydroxyl-functionalization did not cause preferential polymer-gas interactions but primarily elicited diffusion-dominated changes owing to a tightened microstructure more resistant to CO2-induced dilations. Solution-processable hydroxyl-functionalized PIM-type polyimides provide a new platform of advanced materials that unites the high selectivities of low-free-volume polymers with the high permeabilities of PIM-type materials particularly for natural gas sweetening applications.

  19. Study of sorption of two sulfonylurea type of herbicides and their additives on soils and soil components.

    Földényi, Rita; Tóth, Zoltán; Samu, Gyöngyi; Érsek, Csaba


    The sorption of two sulfonylurea type herbicides (chlorsulfuron: (1-(2-chlorophenylsulfonyl)-3-(4-methoxy-6-methyl-1,3,5-triazin-2-yl)urea; tribenuron methyl: (methyl-2-[N-(4-methoxy-6-methyl-1,3,5-triazin-2-yl)-3-(methyl-ureido)-sulfonyl]-benzoate) was studied on sand and chernozem soil adsorbents. Experimental results for solutions prepared from the pure ingredients were compared to those prepared from the appropriate formulated commercial products. At small concentrations, the extent of adsorption of the active ingredient was higher than from the formulation containing solutions. Environmental fate and effects of the forming agents are less investigated because they rarely have concentration limits recommended by authorities. In addition to the adsorption of active ingredients, therefore, the sorption behavior of a widely used additive Supragil WP (sodium diisopropyl naphthalene sulphonate) was also studied. This dispersant is an anionic forming agent applied in a lot of pesticide formulations. Using three different soils (sand, brown forest, chernozem) as adsorbents two-step isotherms were obtained. The role of the soil organic matter (OM) was significant in the adsorption mechanism because the adsorbed amounts of the dispersant correlated with the specific surface area as well as with the total organic carbon (TOC) content of the soils. The sorption behavior indicates the operation of hydrophobic interaction mechanism between the soil OM and the dispersant. These results are supported by our further sorption experiments on clays, too. Zeta potential measurements seem to be promising for the interpretation of multi-step isotherms. The application of this technique proved that higher concentrations of the anionic forming agent assisted the peptization of soil organic matter (SOM) resulting in stable colloidal solution dominated by negative charges. Since the pesticides investigated are also anionic at the studied pH (7 and 8.3) the dissolved organics lead to the

  20. Decontamination Strategy for Large Area and/or Equipment Contaminated with Chemical and Biological Agents using a High Energy Arc Lamp (HEAL)

    Schoske, Richard [ORNL; Kennedy, Patrick [ORNL; Duty, Chad E [ORNL; Smith, Rob R [ORNL; Huxford, Theodore J [ORNL; Bonavita, Angelo M [ORNL; Engleman, Greg [ORNL; Vass, Arpad Alexander [ORNL; Griest, Wayne H [ORNL; Ilgner, Ralph H [ORNL; Brown, Gilbert M [ORNL


    A strategy for the decontamination of large areas and or equipment contaminated with Biological Warfare Agents (BWAs) and Chemical Warfare Agents (CWAs) was demonstrated using a High Energy Arc Lamp (HEAL) photolysis system. This strategy offers an alternative that is potentially quicker, less hazardous, generates far less waste, and is easier to deploy than those currently fielded by the Department of Defense (DoD). For example, for large frame aircraft the United States Air Force still relies on the combination of weathering (stand alone in environment), air washing (fly aircraft) and finally washing the aircraft with Hot Soapy Water (HSW) in an attempt to remove any remaining contamination. This method is laborious, time consuming (upwards of 12+ hours not including decontamination site preparation), and requires large amounts of water (e.g., 1,600+ gallons for a single large frame aircraft), and generates large amounts of hazardous waste requiring disposal. The efficacy of the HEAL system was demonstrated using diisopropyl methyl phosphonate (DIMP) a G series CWA simulant, and Bacillus globigii (BG) a simulant of Bacillus anthracis. Experiments were designed to simulate the energy flux of a field deployable lamp system that could stand-off 17 meters from a 12m2 target area and uniformly expose a surface at 1360 W/m2. The HEAL system in the absence of a catalyst reduced the amount of B. globigii by five orders of magnitude at a starting concentration of 1.63 x 107 spores. In the case of CWA simulants, the HEAL system in the presence of the catalyst TiO2 effectively degraded DIMP sprayed onto a 100mm diameter Petri dish in 5 minutes.

  1. Crystal Structure of Human Senescence Marker Protein 30: Insights Linking Structural, Enzymatic, and Physiological Functions

    Chakraborti, Subhendu; Bahnson, Brian J. (Delaware)


    Human senescence marker protein 30 (SMP30), which functions enzymatically as a lactonase, hydrolyzes various carbohydrate lactones. The penultimate step in vitamin-C biosynthesis is catalyzed by this enzyme in nonprimate mammals. It has also been implicated as an organophosphate hydrolase, with the ability to hydrolyze diisopropyl phosphofluoridate and other nerve agents. SMP30 was originally identified as an aging marker protein, whose expression decreased androgen independently in aging cells. SMP30 is also referred to as regucalcin and has been suggested to have functions in calcium homeostasis. The crystal structure of the human enzyme has been solved from X-ray diffraction data collected to a resolution of 1.4 {angstrom}. The protein has a 6-bladed {beta}-propeller fold, and it contains a single metal ion. Crystal structures have been solved with the metal site bound with either a Ca{sup 2+} or a Zn{sup 2+} atom. The catalytic role of the metal ion has been confirmed by mutagenesis of the metal coordinating residues. Kinetic studies using the substrate gluconolactone showed a k{sub cat} preference of divalent cations in the order Zn{sup 2+} > Mn{sup 2+} > Ca{sup 2+} > Mg{sup 2+}. Notably, the Ca{sup 2+} had a significantly higher value of K{sub d} compared to those of the other metal ions tested (566, 82, 7, and 0.6 {micro}m for Ca{sup 2+}, Mg{sup 2+}, Zn{sup 2+}, and Mn{sup 2+}, respectively), suggesting that the Ca{sup 2+}-bound form may be physiologically relevant for stressed cells with an elevated free calcium level.

  2. Oxidative degradation of alternative gasoline oxygenates in aqueous solution by ultrasonic irradiation: Mechanistic study

    Kim, Duk Kyung, E-mail: [Department of Physical Science, Auburn University Montgomery, Montgomery, AL 36117 (United States); O' Shea, Kevin E., E-mail: [Department of Chemistry and Biochemistry, Florida International University, University Park, Miami, FL 33199 (United States); Cooper, William J. [Department of Civil and Environmental Engineering, Urban Water Research Center, University of California Irvine, Irvine, CA 92697-2175 (United States)


    Widespread pollution has been associated with gasoline oxygenates of branched ethers methyl tert-butyl ether (MTBE), di-isopropyl ether (DIPE), ethyl tert-butyl ether (ETBE), and tert-amyl ether (TAME) which enter groundwater. The contaminated plume develops rapidly and treatment for the removal/destruction of these ethers is difficult when using conventional methods. Degradation of MTBE, with biological methods and advanced oxidation processes, are rather well known; however, fewer studies have been reported for degradation of alternative oxygenates. Degradation of alternative gasoline oxygenates (DIPE, ETBE, and TAME) by ultrasonic irradiation in aqueous oxygen saturation was investigated to elucidate degradation pathways. Detailed degradation mechanisms are proposed for each gasoline oxygenate. The common major degradation pathways are proposed to involve abstraction of {alpha}-hydrogen atoms by hydroxyl radicals generated during ultrasound cavitation and low temperature pyrolytic degradation of ETBE and TAME. Even some of the products from {beta}-H abstraction overlap with those from high temperature pyrolysis, the effect of {beta}-H abstraction was not shown clearly from product study because of possible 1,5 H-transfer inside cavitating bubbles. Formation of hydrogen peroxide and organic peroxides was also determined during sonolysis. These data provide a better understanding of the degradation pathways of gasoline oxygenates by sonolysis in aqueous solutions. The approach may also serve as a model for others interested in the details of sonolysis. - Highlights: Black-Right-Pointing-Pointer Gasoline oxygenates (ETBE, TAME, DIPE) were completely degraded after 6 hours under ultrasonic irradiation in O{sub 2} saturation. Black-Right-Pointing-Pointer The major degradation pathways were proposed to involve abstraction of {alpha}-hydrogen atoms by hydroxyl radicals and low temperature pyrolytic degradation. Black-Right-Pointing-Pointer The effect of {beta

  3. Identification and separation of the organic compounds in coal-gasification condensate waters. [5,5 dimethyl hydantoin, dihydroxy benzenes, acetonitrile

    Mohr, D.H. Jr.; King, C.J.


    A substantial fraction of the organic solutes in condensate waters from low-temperature coal-gasification processes are not identified by commonly employed analytical techniques, have low distriution coefficients (K/sub C/) into diisopropyl ether (DIPE) or methyl isobutyl ketone (MIBK), and are resistant to biological oxidation. These compounds represent an important wastewater-treatment problem. Analytical techniques were developed to detect these polar compounds, and the liquid-liquid phase equilibria were measured with several solvents. A high-performance liquid - chromatography (HPLC) technique was employed to analyze four condensate-water samples from a slagging fixed-bed gasifier. A novel sample-preparation technique, consisting of an azeotropic distillation with isopropanol, allowed identification of compounds in the HPLC eluant by combined gas chromatography and mass spectrometry. 5,5-dimethyl hydantoin and related compounds were identified in condensate waters for the first time, and they account for 1 to 6% of the chemical oxygen demand (COD). Dimethyl hydatoin has a K/sub D/ of 2.6 into tributyl phosphate (TBP) and much lower K/sub D/ values into six other solvents. It is also resistant to biological oxidation. Phenols (59 to 76% of the COD), dihydroxy benzenes (0.02 to 9.5% of the COD), and methanol, acetonitrile, and acetone (15% of the COD in one sample) were also detected. Extraction with MIBK removed about 90% of the COD. MIBK has much higher K/sub D/ values than DIPE for dihydroxy benzenes. Chemical reactions occurred during storage of condensate-water samples. The reaction products had low K/sub D/ values into MIBK. About 10% of the COD had a K/sub D/ of nearly zero into MIBK. These compounds were not extracted by MIBK over a wide range of pH. 73 references, 6 figures, 35 tables.

  4. Characteristics of a nickel thin film and formation of nickel silicide by using remote plasma atomic layer deposition with Ni( i Pr-DAD)2

    Kim, Jinho; Jang, Woochool; Park, Jingyu; Jeon, Heeyoung; Kim, Hyunjung; Yuh, Junhan; Jeon, Hyeongtag


    In this study, the characteristics of nickel thin film deposited by remote plasma atomic layer deposition (RPALD) on p-type Si substrate and formation of nickel silicide using rapid thermal annealing were determined. Bis(1,4-di-isopropyl-1,3-diazabutadienyl)nickel, Ni(iPr-DAD)2, was used as a Ni precursor and ammonia plasma was used as a reactant. This was the first attempt to deposit Ni thin film using Ni(iPr-DAD)2 as a precursor for the ALD process. The RPALD Ni film was deposited with a growth rate of around 2.2{\\AA}/cycle at 250 {\\deg}C and showed significant low resistivity of 33 {\\mu}{\\Omega}cm with a total impurity concentration of around 10 at. %.The impurities of the thin film, carbon and nitrogen, were existent by the forms of C-C and C-N in a bonding state. The impurities removal tendency was investigated by comparing of experimental conditions, namely process temperature and pressure. Nitrogen impurity was removed by thermal desorption during each ALD cycle and carbon impurity was reduced by the optimizing of the process pressure which is directly related with a mean free path of NH3 plasma. After Ni deposition, nickel silicide was formed by RTA in a vacuum ambient for 1 minute. A nickel silicide layer from ALD Ni and PVD Ni was compared at the annealing temperature from 500 to 900 {\\deg}C. NiSi from ALD Ni showed better thermal stability due to the contribution of small amounts of carbon and nitrogen in the asdeposited Ni thin film. Degradation of the silicide layer was effectively suppressed with a use of ALD Ni.

  5. Dipeptidyl peptidase 4 - An important digestive peptidase in Tenebrio molitor larvae.

    Tereshchenkova, Valeriia F; Goptar, Irina A; Kulemzina, Irina A; Zhuzhikov, Dmitry P; Serebryakova, Marina V; Belozersky, Mikhail A; Dunaevsky, Yakov E; Oppert, Brenda; Filippova, Irina Yu; Elpidina, Elena N


    Dipeptidyl peptidase 4 (DPP 4) is a proline specific serine peptidase that plays an important role in different regulatory processes in mammals. In this report, we isolated and characterized a unique secreted digestive DPP 4 from the anterior midgut of a stored product pest, Tenebrio molitor larvae (TmDPP 4), with a biological function different than that of the well-studied mammalian DPP 4. The sequence of the purified enzyme was confirmed by mass-spectrometry, and was identical to the translated RNA sequence found in a gut EST database. The purified peptidase was characterized according to its localization in the midgut, and substrate specificity and inhibitor sensitivity were compared with those of human recombinant DPP 4 (rhDPP 4). The T. molitor enzyme was localized mainly in the anterior midgut of the larvae, and 81% of the activity was found in the fraction of soluble gut contents, while human DPP 4 is a membrane enzyme. TmDPP 4 was stable in the pH range 5.0-9.0, with an optimum activity at pH 7.9, similar to human DPP 4. Only specific inhibitors of serine peptidases, diisopropyl fluorophosphate and phenylmethylsulfonyl fluoride, suppressed TmDPP 4 activity, and the specific dipeptidyl peptidase inhibitor vildagliptin was most potent. The highest rate of TmDPP 4 hydrolysis was found for the synthetic substrate Arg-Pro-pNA, while Ala-Pro-pNA was a better substrate for rhDPP 4. Related to its function in the insect midgut, TmDPP 4 efficiently hydrolyzed the wheat storage proteins gliadins, which are major dietary proteins of T. molitor.

  6. Hydrolysis of VX on Concrete: Rate of Degradation by Direct Surface Interrogation using an Ion Trap Secondary Ion Mass Spectrometer

    Groenewold, Gary Steven; Appelhans, Anthony David; Gresham, Garold Linn; Olson, John Eric; Rowland, B.; Williams, j.; Jeffery, M. T.


    The nerve agent VX (O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate) is lethal at very low levels of exposure, which can occur by dermal contact with contaminated surfaces. Hence, behavior of VX in contact with common urban or industrial surfaces is a subject of acute interest. In the present study, VX was found to undergo complete degradation when in contact with concrete surfaces. The degradation was directly interrogated at submonolayer concentrations by periodically performing secondary ion mass spectrometry (SIMS) analyses after exposure of the concrete to VX. The abundance of the [VX + H]+ ion in the SIMS spectra was observed to decrease in an exponential fashion, consistent with first-order or pseudo-first-order behavior. This phenomenon enabled the rate constant to be determined at 0.005 min-1 at 25 C, which corresponds to a half-life of about 3 h on the concrete surface. The decrease in [VX + H]+ was accompanied by an increase in the abundance of the principal degradation product diisopropylaminoethanethiol (DESH), which arises by cleavage of the P-S bond. Degradation to form DESH is accompanied by the formation of ethyl methylphosphonic acid, which is observable only in the negative ion spectrum. A second degradation product was also implicated, which corresponded to a diisopropylvinylamine isomer (perhaps N,N-diisopropyl aziridinium) that arose via cleavage of the S-C bond. No evidence was observed for the formation of the toxic S-2-diisopropylaminoethyl methylphosphonothioic acid. The degradation rate constants were measured at four different temperatures (24-50 C), which resulted in a linear Arrhenius relationship and an activation energy of 52 kJ mol-1. This value agrees with previous values observed for VX hydrolysis in alkaline solutions, which suggests that the degradation of submonolayer VX is dominated by alkaline hydrolysis within the adventitious water film on the concrete surface.

  7. Self-assembled PEG-b-PDPA-b-PGEM copolymer nanoparticles as protein antigen delivery vehicles to dendritic cells: preparation, characterization and cellular uptake

    Li, Pan; Zhou, Junhui; Huang, Pingsheng; Zhang, Chuangnian; Wang, Weiwei; Li, Chen; Kong, Deling


    Antigen uptake by dendritic cells (DCs) is a key step for initiating antigen-specific T cell immunity. In the present study, novel synthetic polymeric nanoparticles were prepared as antigen delivery vehicles to improve the antigen uptake by DCs. Well-defined cationic and acid-responsive copolymers, monomethoxy poly(ethylene glycol)-block-poly(2-(diisopropyl amino) ethyl methacrylate)-block-poly(2-(guanidyl) ethyl methacrylate) (mPEG-b-PDPA-b-PGEM, PEDG) were synthesized by reversible addition-fragmentation chain transfer polymerization of 2-(diisopropylamino)ethyl methacrylate) and N-(tert-butoxycarbonyl) amino ethyl methacrylate monomers, followed by deprotection of tert-butyl protective groups and guanidinylation of obtained primary amines. 1H NMR, 13C NMR and GPC results indicated the successful synthesis of well-defined PEDG copolymers. PEDG copolymers could self-assemble into nanoparticles in aqueous solution, which were of cationic surface charges and showed acid-triggered disassembly contributed by PGEM and PDPA moieties, respectively. Significantly, PEDG nanoparticles could effectively condense with negatively charged model antigen ovalbumin (OVA) to form OVA/PEDG nanoparticle formulations with no influence on its secondary and tertiary structures demonstrating by far-UV circular dichroism and UV–vis spectra. In vitro antigen cellular uptake by bone marrow DCs (BMDCs) indicated using PEDG nanoparticles as antigen delivery vehicles could significantly improve the antigen uptake efficiency of OVA compared with free OVA or the commercialized Alum adjuvant. Moreover, as the surface cationic charges of OVA/PEDG nanoparticle formulations reduced, the uptake efficiency decreased correspondingly. Collectively, our work suggests that guanidinylated, cationic and acid-responsive PEDG nanoparticles represent a new kind of promising antigen delivery vehicle to DCs and hold great potential to serve as immunoadjuvants in the development of vaccines. PMID:28149525

  8. Conceptual design and retrofitting of the coal-gasification wastewater treatment process

    Gai, H.; Jiang, Y.; Qian, Y.; Kraslawski, A. [South China University of Technology, Ghangzhou (China). School of Chemical Engineering


    The coal-gasification wastewater treatment is the most difficult pollution control task for coal-gasification plants. It is identified that there are two serious problems occurring in the current treatment process, i.e., low performance of phenols removal and plugging induced by ammonia salts. A new treatment process is proposed in this paper to solve these severe problems and pursue clean production. First, ammonia stripping is accomplished before phenols recovery to reduce pH value of the wastewater and to improve the phenols removal performance of extraction. Second, a complex stripper with a side draw is introduced to stripping ammonia and sour gas simultaneously. It is done to eliminate the ionic interaction during stripping and to improve the removal performance of ammonia and sour gas (carbon dioxide and hydrogen sulphide). Finally, methyl isobutyl ketone (MIBK) is used as extraction solvent instead of diisopropyl ether (DIPE) for further improvement of the phenols removal performance. Conceptual design of the proposed process is accomplished for a large-scale coal-gasification plant based on process simulation. With the proposed process, the concentration of carbon dioxide, hydrogen sulphide and ammonia in wastewater are reduced to trace, less than 10 mg/L, and about 30 mg/L, respectively. As a result, pH value of the wastewater is reduced from >9 to <7 before extraction, thus the phenols removal performance is greatly improved. Compare to the current process, the removal ratios increase from 60% to 99% for carbon dioxide, 96% to 99.6% for ammonia, and 80% to 94% for total phenols using the proposed process. In consequence, the biochemical treatment of wastewater becomes easier. The economical analysis shows that the operating cost of the proposed process is much lower than that of the current process.

  9. Deletion of degQ gene enhances outer membrane vesicle production of Shewanella oneidensis cells.

    Ojima, Yoshihiro; Mohanadas, Thivagaran; Kitamura, Kosei; Nunogami, Shota; Yajima, Reiki; Taya, Masahito


    Shewanella oneidensis is a Gram-negative facultative anaerobe that can use a wide variety of terminal electron acceptors for anaerobic respiration. In this study, S. oneidensis degQ gene, encoding a putative periplasmic serine protease, was cloned and expressed. The activity of purified DegQ was inhibited by diisopropyl fluorophosphate, a typical serine protease-specific inhibitor, indicating that DegQ is a serine protease. In-frame deletion and subsequent complementation of the degQ were carried out to examine the effect of envelope stress on the production of outer membrane vesicles (OMVs). Analysis of periplasmic proteins from the resulting S. oneidensis strain showed that deletion of degQ induced protein accumulation and resulted in a significant decrease in protease activity within the periplasmic space. OMVs from the wild-type and mutant strains were purified and observed by transmission electron microscopy. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of the OMVs showed a prominent band at ~37 kDa. Nanoliquid chromatography-tandem mass spectrometry analysis identified three outer membrane porins (SO3896, SO1821, and SO3545) as dominant components of the band, suggesting that these proteins could be used as indices for comparing OMV production by S. oneidensis strains. Quantitative evaluation showed that degQ-deficient cells had a fivefold increase in OMV production compared with wild-type cells. Thus, the increased OMV production following the deletion of DegQ in S. oneidensis may be responsible for the increase in envelope stress.

  10. Synthesis and structural determination of zinc complexes based on an anilido-aldimine ligand containing an O-donor pendant arm: zinc alkoxide derivative as an efficient initiator for ring-opening polymerization of cyclic esters.

    Wang, Chao-Hsiang; Li, Chen-Yu; Huang, Bor-Hunn; Lin, Chu-Chieh; Ko, Bao-Tsan


    Zinc complexes bearing the anilido-aldiminate AA(OMe) ligand (AA(OMe)-H = (E)-2,6-diisopropyl-N-(2-(((2-methoxyethyl)imino)methyl)phenyl)aniline) were synthesized in a stepwise method and were structurally characterized. The reaction of AA(OMe)-H (1) with one equivalent of diethyl zinc (ZnEt2) furnishes a three-coordinated and mononuclear zinc complex [(AA(OMe))ZnEt] (2). Further reaction of 2 with a stoichiometric amount of benzyl alcohol (BnOH) affords a four-coordinated and dinuclear zinc benzylalkoxide complex [(AA(OMe))Zn(μ-OBn)]2 (3). In the presence of two equivalents of AA(OMe)-H with ZnEt2, a homoleptic and four-coordinated zinc complex [(AA(OMe))2Zn] (4) is formed. The geometry around the zinc centres of 3 and 4 are both distorted tetrahedrals, while 2 adopts a different coordination mode with a slightly distorted trigonal planar geometry. The variable-temperature (1)H NMR studies of 3 illustrate that 3 exhibits a dinuclear structure in solution at low temperature as well as in the solid state. While raising the temperature, it drifts towards dissociation to form a mononuclear zinc benzylalkoxide species, which coexists in solution. The ring-opening polymerizations of ε-caprolactone (ε-CL) and β-butyrolactone (β-BL) catalyzed by complexes 3 and 4 are investigated. The ε-CL and β-BL polymerizations initiated by zinc alkoxide 3 were demonstrated to have living characteristics and to proceed in a controlled manner with narrow polydispersity indices (PDIs high monomer-to-initiator ratio (1200/1) initiated by 3 has also been reported.

  11. Iterative tandem catalysis of secondary diols and diesters to chiral polyesters.

    van As, Bart A C; van Buijtenen, Jeroen; Mes, Tristan; Palmans, Anja R A; Meijer, E W


    The well-known dynamic kinetic resolution of secondary alcohols and esters was extended to secondary diols and diesters to afford chiral polyesters. This process is an example of iterative tandem catalysis (ITC), a polymerization method where the concurrent action of two fundamentally different catalysts is required to achieve chain growth. In order to procure chiral polyesters of high enantiomeric excess value (ee) and good molecular weight, the catalysts employed need to be complementary and compatible during the polymerization reaction. We here show that Shvo's catalyst and Novozym 435 fulfil these requirements. The optimal polymerization conditions of 1,1'-(1,3-phenylene) diethanol (1,3-diol) and diisopropyl adipate required 2 mol% Shvo's catalyst and 12 mg Novozym 435 per mmol alcohol group in the presence of 0.5 M 2,4-dimethyl-3-pentanol as the hydrogen donor. With these conditions, chiral polyesters were obtained with peak molecular weights up to 15 kDa, an ee value up to 99% and with 1-3 % ketone end groups. Also with the structural isomer, 1,4-diol, a chiral polyester was obtained, albeit with lower molecular weight (8.3 kDa) and slightly lower ee (94%). Aliphatic secondary diols also resulted in enantio-enriched polymers but at most an ee of 46 % was obtained with molecular weights in the range of 3.3-3.7 kDa. This low ee originates from the intrinsic low enantioselectivity of Novozym 435 for this type of secondary aliphatic diols. The results presented here show that ITC can be applied to procure chiral polyesters with good molecular weight and high ee from optically inactive AA-BB type monomers.

  12. Copper(I Complexes of Mesoionic Carbene: Structural Characterization and Catalytic Hydrosilylation Reactions

    Stephan Hohloch


    Full Text Available Two series of different Cu(I-complexes of “click” derived mesoionic carbenes are reported. Halide complexes of the type (MICCuI (with MIC = 1,4-(2,6-diisopropyl-phenyl-3-methyl-1,2,3-triazol-5-ylidene (for 1b, 1-benzyl-3-methyl-4-phenyl-1,2,3-triazol-5-ylidene (for 1c and cationic complexes of the general formula [Cu(MIC2]X (with MIC =1,4-dimesityl-3-methyl-1,2,3-triazol-5-ylidene, X = CuI2− (for 2á, 1,4-dimesityl-3-methyl-1,2,3-triazol-5-ylidene, X = BF4− (for 2a, 1,4-(2,6-diisopropylphenyl-3-methyl-1,2,3-triazol-5-ylidene, X = BF4− (for 2b, 1-benzyl-3-methyl-4-phenyl-1,2,3-triazol-5-ylidene, X = BF4− (for 2c have been prepared from CuI or [Cu(CH3CN4](BF4 and the corresponding ligands, respectively. All complexes were characterized by elemental analysis and standard spectroscopic methods. Complexes 2á and 1b were studied by single-crystal X-ray diffraction analysis. Structural analysis revealed 2á to adopt a cationic form as [Cu(MIC2](CuI2 and comparison of the NMR spectra of 2á and 2a confirmed this conformation in solution. In contrast, after crystallization complex 1b was found to adopt the desired neutral form. All complexes were tested for the reduction of cyclohexanone under hydrosilylation condition at elevated temperatures. These complexes were found to be efficient catalysts for this reaction. 2c was also found to catalyze this reaction at room temperature. Mechanistic studies have been carried out as well.

  13. p75(NTR) antagonists attenuate photoreceptor cell loss in murine models of retinitis pigmentosa.

    Platón-Corchado, María; Barcelona, Pablo F; Jmaeff, Sean; Marchena, Miguel; Hernández-Pinto, Alberto M; Hernández-Sánchez, Catalina; Saragovi, H Uri; de la Rosa, Enrique J


    ProNGF signaling through p75(NTR) has been associated with neurodegenerative disorders. Retinitis pigmentosa (RP) comprises a group of inherited retinal dystrophies that causes progressive photoreceptor cell degeneration and death, at a rate dependent on the genetic mutation. There are more than 300 mutations causing RP, and this is a challenge to therapy. Our study was designed to explore a common mechanism for p75(NTR) in the progression of RP, and assess its potential value as a therapeutic target. The proNGF/p75(NTR) system is present in the dystrophic retina of the rd10 RP mouse model. Compared with wild-type (WT) retina, the levels of unprocessed proNGF were increased in the rd10 retina at early degenerative stages, before the peak of photoreceptor cell death. Conversely, processed NGF levels were similar in rd10 and WT retinas. ProNGF remained elevated throughout the period of photoreceptor cell loss, correlating with increased expression of α2-macroglobulin, an inhibitor of proNGF processing. The neuroprotective effect of blocking p75(NTR) was assessed in organotypic retinal cultures from rd10 and RhoP mouse models. Retinal explants treated with p75(NTR) antagonists showed significantly reduced photoreceptor cell death, as determined by the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay and by preservation of the thickness of the outer nuclear layer (ONL), where photoreceptor nuclei are located. This effect was accompanied by decreased retinal-reactive gliosis and reduced TNFα secretion. Use of p75(NTR) antagonist THX-B (1,3-diisopropyl-1-[2-(1,3-dimethyl-2,6-dioxo-1,2,3,6-tetrahydro-purin-7-yl)-acetyl]-urea) in vivo in the rd10 and RhoP mouse models, by a single intravitreal or subconjunctival injection, afforded neuroprotection to photoreceptor cells, with preservation of the ONL. This study demonstrates a role of the p75(NTR)/proNGF axis in the progression of RP, and validates these proteins as therapeutic targets

  14. Resolving pathways of interaction of mipafox and a sarin analog with human acetylcholinesterase by kinetics, mass spectrometry and molecular modeling approaches.

    Mangas, I; Taylor, P; Vilanova, E; Estévez, J; França, T C C; Komives, E; Radić, Z


    The hydroxyl oxygen of the catalytic triad serine in the active center of serine hydrolase acetylcholinesterase (AChE) attacks organophosphorus compounds (OPs) at the phosphorus atom to displace the primary leaving group and to form a covalent bond. Inhibited AChE can be reactivated by cleavage of the Ser-phosphorus bond either spontaneously or through a reaction with nucleophilic agents, such as oximes. At the same time, the inhibited AChE adduct can lose part of the molecule by progressive dealkylation over time in a process called aging. Reactivation of the aged enzyme has not yet been demonstrated. Here, our goal was to study oxime reactivation and aging reactions of human AChE inhibited by mipafox or a sarin analog (Flu-MPs, fluorescent methylphosphonate). Progressive reactivation was observed after Flu-MPs inhibition using oxime 2-PAM. However, no reactivation was observed after mipafox inhibition with 2-PAM or the more potent oximes used. A peptide fingerprinted mass spectrometry (MS) method, which clearly distinguished the peptide with the active serine (active center peptide, ACP) of the human AChE adducted with OPs, was developed by MALDI-TOF and MALDI-TOF/TOF. The ACP was detected with a diethyl-phosphorylated adduct after paraoxon inhibition, and with an isopropylmethyl-phosphonylated and a methyl-phosphonylated adduct after Flu-MPs inhibition and subsequent aging. Nevertheless, nonaged nonreactivated complexes were seen after mipafox inhibition and incubation with oximes, where MS data showed an ACP with an NN diisopropyl phosphoryl adduct. The kinetic experiments showed no reactivation of activity. The computational molecular model analysis of the mipafox-inhibited hAChE plots of energy versus distance between the atoms separated by dealkylation showed a high energy demand, thus little aging probability. However, with Flu-MPs and DFP, where aging was observed in our MS data and in previously published crystal structures, the energy demand calculated

  15. Synthesis and structural characterization of monomeric mercury(II) selenolate complexes derived from 2-phenylbenzamide ligands.

    Patel, Saket; Meenakshi; Hodage, Ananda S; Verma, Ajay; Agrawal, Shailendra; Yadav, Abhimanyu; Kumar, Sangit


    Monomeric Hg(II) selenolate complexes derived from 2-phenylbenzamide ligands were prepared by oxidative addition of diselenides [{C6H4(CONR2)Se}2, R = Me, Et, iPr] to elemental Hg and reductive cleavage of the Se–N bond of isoselenazolone derivatives [(NO2)C6H3(CONSe)R, (R = allyl, nbutyl)] followed by the treatment with HgCl2. The complexes have been characterized by multinuclear NMR (1H, 13C and 77Se) spectroscopy and mass spectrometry which suggest the monomeric form of these in solution. The molecular structures of diselenides [C6H4(CONR2)Se]2 and mercury selenolates [Hg{(NO2)C6H3(CONH-C3H5) Se}2], [Hg{C6H4(CONiPr2)Se}2] and [Hg{C6H4(CONMe2)Se}2] were established by a single crystal X-ray diffraction study. Diselenides show strong intramolecular non-bonded Se⋯O interactions, which are influenced by the nature of C(O)NR̲2 and decrease with the sterically bulky alkyl substituent (Se⋯O =2.823 Å for R = di-Me, 2.760 Å for R = allyl, and 3.157 Å for R = di-iPr). Mercury complexes derived from less bulky 2-phenyl-N,N-dialkylbenzamide ligands associated with poor or no intramolecular nonbonded Hg⋯O interactions (4.91 Å for R = di-Me, 4.199 Å for R = allyl) and instead strong intermolecular Hg⋯O [2.792(3) and 2.820(4) Å] for di-Me and allyl and Hg⋯Se [3.3212(5) and 3.4076(8) Å] interactions were observed which lead to a dimeric form in the crystals. On the other hand, the mercury complex derived from the sterically bulky diisopropyl amide ligand shows a strong intramolecular non-bonded Hg⋯O (2.860 Å) interaction, adopts linear geometry and exists as a monomer. Thermogravimetric analysis (TGA) of the mercury selenolate complexes revealed two-step decomposition which leads to the formation of HgSe. The mercury selenolate complex 3c derived from the sterically bulky 2-phenyl-N,Ndiisopropylbenzamide ligand decomposed to give HgSe in the range of 220-300 °C.

  16. 球形MgCl2载体催化剂催化1-丁烯聚合%Polymerization of 1-butene with spherical MgCl2-supported catalyst

    任笑飞; 任合刚; 白鹏; 杨敏; 吴之禄; 郝月梅; 刘宾元


    在以三乙基铝(AlEt3)为助催化剂、n(AD/n(Ti)为300、聚合压力为0.10 MPa、聚合温度为30℃、通人氢气3 mL、环己基甲基二甲氧基硅烷(CHMMS)与Al的摩尔比为0.033、聚合2h的条件下,球形MgCl2载体催化剂的活性为607g/g,聚1-丁烯的等规指数为82.3%.依催化剂活性大小,外给电子体的顺序为:CHMMS,二环戊基二甲氧基硅烷(DCPMS),二异丁基二甲氧基硅烷(DIBMS),二异丙基二甲氧基硅烷(DIPMS),二苯基二甲氧基硅烷(DDS);依聚1-丁烯等规指数大小,外给电子体的顺序为DCPMS.DIPMS,DIBMS,CHMMS,DDS.%The activity of the spherical MgCl2-supported catalyst for 1-butene polymerization reached 607 g/g and the isotacticity index of poly( 1-butene) prepared with the catalyst attained 82.3% under the following optimal conditions: triethyl aluminum as cocatalyst, molar ratio of Al to Ti 300, polymerization pressure 0.10 MPa, polymerization temperature 30℃, hydrogen 3 mL, molar ratio of cyclohexyl methyl dimethoxy silane (CHMMS) to Al 0.033 and reaction time 2 hr. The ranking of external electron donors could be expressed in descending order on the basis of either the catalyst activity as CHMMS, dicyclopentyl dimethoxy silane (DCPMS), diisobutyl dimethoxy silane (DIBMS), diisopropyl dimethoxy silane (DIPMS) and diphenyl dimethoxy silane(DDS), or the isotacticity index of poly(l-butene) as DCPMS, DIPMS, DIBMS, CHMMS and DDS.

  17. 球形MgCl2载体催化剂催化1-丁烯聚合%Polymerization of 1-butene with spherical MgCl2-supported catalyst

    任笑飞; 任合刚; 白鹏; 杨敏; 吴之禄; 郝月梅; 刘宾元


    在以三乙基铝(AlEt3)为助催化剂、n(Al)/n(Ti)为300、聚合压力为0.10 MPa、聚合温度为30℃、通入氢气3 mL、环己基甲基二甲氧基硅烷(CHMMS)与Al的摩尔比为0.033、聚合2h的条件下,球形MgCl2载体催化刺的活性为607g/g,聚1-丁烯的等规指数为82.3%.依催化剂活性大小,外给电子体的顺序为:CHMMS,二环戊基二甲氧基硅烷(DCPMS),二异丁基二甲氧基硅烷(DIBMS),二异丙基二甲氧基硅烷(DIPMS),二苯基二甲氧基硅烷(DDS);依聚1-丁烯等规指数大小,外给电子体的顺序为DCPMS,DIPMS,DIBMS,CHMMS,DDS.%The activity of the spherical MgCl2-supported catalyst for 1-butene polymerization reached 607 g/g and the isotacticity index of poly(l-butene) prepared with the catalyst attained 82.3% under the following optimal conditions: triethyl aluminum as cocatalyst, molar ratio of Al to Ti 300, polymerization pressure 0.10 MPa, polymerization temperature 30 ℃, hydrogen 3 mL, molar ratio of cyclohexyl methyl dimethoxy silane (CHMMS) to Al 0.033 and reaction time 2 hr. The ranking of external electron donors could be expressed in descending order on the basis of either the catalyst activity as CHMMS, dicyclopentyl dimethoxy silane(DCPMS), diisobutyl dimethoxy silane(DIBMS), diisopropyl dimethoxy silane(DIPMS) and diphenyl dimethoxy silane(DDS), or the isotacticity index of poly(l-butene) as DCPMS, DIPMS, DIBMS, CHMMS and DDS.

  18. In vitro and in vivo comparison of sulfur donors as antidotes to acute cyanide intoxication.

    Baskin, S I; Porter, D W; Rockwood, G A; Romano, J A; Patel, H C; Kiser, R C; Cook, C M; Ternay, A L


    Antidotes for cyanide (CN) intoxication include the use of sulfane sulfur donors (SSDs), such as thiosulfate, which increase the conversion of CN to thiocyanate by the enzyme rhodanese. To develop pretreatments that might be useful against CN, SSDs with greater lipophilicity than thiosulfate were synthesized and assessed. The ability of SSDs to protect mice against 2LD50 of sodium cyanide (NaCN) administered either 15 or 60 min following administration of an SSD was assessed. To study the mechanism of action of the SSD, the candidate compounds were examined in vitro for their effect on rhodanese and 3-mercaptopyruvate sulfurtransferase (MST) activity under increasing SSD concentrations. Tests were conducted on nine candidate SSDs: ICD1021 (3-hydroxypyridin-2-yl N-[(N-methyl-3-aminopropyl)]-2-aminoethyl disulfide dihydrochloride), ICD1022, (3-hydroxypyridin-2-yl N-[(N-methyl-3-aminopropyl)]-2-aminoethyl disulfide trihydrochloride), ICD1584 (diethyl tetrasulfide), ICD1585 (diallyl tetrasulfide), ICD1587 (diisopropyl tetrasulfide); ICD1738 (N-(3-aminopropyl)-2-aminoethyl 2-oxopropyl disulfide dihydrochloride), ICD1816 (3,3'-tetrathiobis-N-acctyl-L-alanine), ICD2214 (2-aminoethyl 4-methoxyphenyl disulfide hydrochloride) and ICD2467 (bis(4-methoxyphenyl) disulfide). These tests demonstrated that altering the chemical substituent of the longer chain sulfide modified the ability of the candidate SSD to protect against CN toxicity. At least two of the SSDs at selected doses provided 100% protection against 2LD50 of NaCN, normally an LD99. All compounds were evaluated using locomotor activity as a measure of potential adverse behavioral effects. Positive hypoactivity relationships were found with several disulfides but none was found with ICD1584, a tetrasulfide. Separate studies suggest that the chemical reaction of potassium cyanide (KCN) and cystine forms the toxic metabolite 2-iminothiazolidine-4-carboxylic acid. An alternative detoxification pathway, one not primarily

  19. 养殖鱼邻苯二甲酸酯的含量分析%Analysis of Phthalic Acid Esters in Muscles Tissue of Cultured Fishes

    蒲德岚; 桑佳陆; 任凯莉; 夏静芬


    目的:为了解宁波地区淡水养殖鱼PAEs污染情况。方法采用液液超声萃取-气质联用法对宁波6个不同养殖点5种淡水养殖鱼体内8种邻苯二甲酸酯含量进行分析。结果宁波地区养殖鱼主要受 DMP、 DEP、 DBP、 DEHP 和 DOP 污染,质量分数最高可达134.1、258.9、249.2、830.8和5029μg/kg;草鱼、鳊鱼、鳙鱼、鲫鱼和乌鳢邻苯二甲酸污染指数PPI分别为9.999、9.735、13.97、8.945和5.809μg/kg。结论宁波地区淡水养殖鱼鱼体邻苯二甲酸酯含量与养殖环境有关,与鱼种无关。%Objective The detection and quantification of eight phthalate esters -dimethyl phthalate ( DMP) , diethyl phthalate ( DEP ) , dibutyl phthalate ( DBP ) , diethylhexyl phthalate ( DEHP ) , diisopropyl phthalate (DIPP), dipropyl phthalate (DPP), butyl benzyl phthalate (BBP), and dioctyl phthalate ( DOP) in the muscle tissues of cultured fishes in six fishponds of ningbo were carried out using liquid -liquid ultrasonic extraction -gas chromatography -mass spectrometry.Results The result showed that DIPP , DPP and BBP were not detected in the samples , and the highest concentration of DMP, DEP, DBP, DEHP and DOP in the fish species were 134.1, 258.9, 249.2, 830.8 and 5 029μg/kg.The phthalate pollution index (PPI) of Grass carp, bream, carp, crucian carp and black flower were 9.999, 9.735, 13.97, 8.945 and 5.809 μg/kg.Conclusions Double -factorial analysis of variance indicated that the differences in fish phthalate levels were not statistically significant at P <0.05 , but the culture environment was significant .

  20. Reaction of nerve agents with phosphate buffer at pH 7.

    Creasy, William R; Fry, Roderick A; McGarvey, David J


    Chemical weapon nerve agents, including isopropyl methylphosphonofluoridate (GB or Sarin), pinacolyl methylphosphonofluoridate (GD or Soman), and S-(2-diisopropylaminoethyl) O-ethyl methylphosphonothioate (VX), are slow to react in aqueous solutions at midrange pH levels. The nerve agent reactivity increases in phosphate buffer at pH 7, relative to distilled water or acetate buffer. Reactions were studied using (31)P NMR. Phosphate causes faster reaction to the corresponding alkyl methylphosphonic acids, and produces a mixed phosphate/phosphonate compound as an intermediate reaction product. GB has the fastest reaction rate, with a bimolecular rate constant of 4.6 × 10(-3) M(-1)s(-1)[PO(4)(3-)]. The molar product branching ratio of GB acid to the pyro product (isopropyl methylphosphonate phosphate anhydride) is 1:1.4, independent of phosphate concentration, and the pyro product continues to react much slower to form GB acid. The pyro product has two doublets in the (31)P NMR spectrum. The rate of reaction for GD is slower than GB, with a rate constant of 1.26 × 10(-3) M(-1)s(-1) [PO(4)(3-)]. The rate for VX is considerably slower, with a rate constant of 1.39 × 10(-5) M(-1)s(-1) [PO(4)(3-)], about 2 orders of magnitude slower than the rate for GD. The rate constant of the reaction of GD with pyrophosphate at pH 8 is 2.04 × 10(-3) min(-1) at a concentration of 0.0145 M. The rate of reaction for diisopropyl fluorophosphate is 2.84 × 10(-3) min(-1) at a concentration of 0.153 M phosphate, a factor of 4 slower than GD and a factor of 15 slower than GB, and there is no detectable pyro product. The half-lives of secondary reaction of the GB pyro product in 0.153 and 0.046 M solution of phosphate are 23.8 and 28.0 h, respectively, which indicates little or no dependence on phosphate.

  1. Imidazenil, a non-sedating anticonvulsant benzodiazepine, is more potent than diazepam in protecting against DFP-induced seizures and neuronal damage.

    Kadriu, Bashkim; Guidotti, Alessandro; Costa, Erminio; Auta, James


    Organophosphate (OP)-nerve agent poisoning may lead to prolonged epileptiform seizure activity, which can result in irreversible neuronal brain damage. A timely and effective control of seizures with pharmacological agents can minimize the secondary and long-term neuropathology that may result from this damage. Diazepam, the current anticonvulsant of choice in the management of OP poisoning, is associated with unwanted effects such as sedation, amnesia, cardio-respiratory depression, anticonvulsant tolerance, and dependence liabilities. In search for an efficacious and safer anticonvulsant benzodiazepine, we studied imidazenil, a potent anticonvulsant that is devoid of sedative action and has a low intrinsic efficacy at alpha1- but is a high efficacy positive allosteric modulator at alpha5-containing GABA(A) receptors. We compared the potency of a combination of 2 mg/kg, i.p. atropine with: (a) imidazenil 0.05-0.5 mg/kg i.p. or (b) equipotent anti-bicuculline doses of diazepam (0.5-5 mg/kg, i.p.), against diisopropyl fluorophosphate (DFP; 1.5 mg/kg, s.c.)-induced status epilepticus and its associated neuronal damage. The severity and frequency of seizure activities were determined by continuous radio telemetry recordings while the extent of neuronal damage and neuronal degeneration were assessed using the TUNEL-based cleaved DNA end-labeling technique or neuron-specific nuclear protein (NeuN)-immunolabeling and Fluoro-Jade B (FJB) staining, respectively. We report here that the combination of atropine and imidazenil is at least 10-fold more potent and longer lasting than the combination with diazepam at protecting rats from DFP-induced seizures and the associated neuronal damage or ongoing degeneration in the anterior cingulate cortex, CA1 hippocampus, and dentate gyrus. While 0.5 mg/kg imidazenil effectively attenuated DFP-induced neuronal damage and the ongoing neuronal degeneration in the anterior cingulate cortex, dentate gyrus, and CA1 hippocampus, 5 mg/kg or

  2. Substitued (E-b-(benzoylacrylic acids suppressed survival of neoplastic human HeLa cells



    Full Text Available The bacteriostatic activity of some of alkyl substituted (E-b-(benzoylacrylic acids was shown earlier. The aim of this study was to investigate the antiproliferative action of 19 alkyl-, or halogeno-, or methoxy-, or acetamido- substituted (E-b-(benzoylacrylic acids, against human cervix carcinoma, HeLa, cells. Target HeLa cells were continuously treated with increasing concentrations of substituted (E-b-(benzoylacrylic acids during two days. The MTT test was used for assessment of the antiproliferative action of this group of compounds. Treatment of HeLa cells with 4-methyl-, 4-fluoro-, 4-chloro-, 4-bromo- and 4-methoxy- derivatives of (E-b-(benzoyl acrylic acid leads to the expression of cytostatic activity against HeLa cells (IC50 were in the range from 31-40 µM. Their antiproliferative action was less than that of the basic compound (E-b-(benzoylacrylic acid whose IC50 was 28.5 µM. The 3,4-dimethyl-, 2,4-dimethyl- and 2,5-dimethyl- derivatives as well as the 4-ethyl- and 3,4-dichloro- and 2,4-dichloro-derivatives, have stronger cytostatic activity than the correspoding monosubstituted and parent compound. Their IC50 were 18.5 µM; 17.5 µM; 17.0 mM; 17.5 µM; 22.0 µM and 18 µM, respectively. The 4-iso-propyl- and 4-n-butyl-derivatives exerted higher cytostatic activity than the compounds with a lower number of methylene -CH2- groups in the substitutent. Their IC50 were 14.5 µM and 6.5 µM respectively. The 2,5-di-iso-propyl- and 4-tert-butyl-derivatives expressed the most strong antiproliferative action against the investigated HeLa cells, IC50 being 4.5 µM and 5.5 µM, respectively. The investigated compounds affected the survival of HeLa cells, expressing a strong structure-activity relationship of the Hansch type.

  3. Stereoselective analysis of nebivolol isomers in human plasma by high-performance liquid chromatography-tandem mass spectrometry: application in pharmacokinetics.

    Neves, Daniel Valente; Vieira, Carolina Pinto; Coelho, Eduardo Barbosa; Marques, Maria Paula; Lanchote, Vera Lucia


    Nebivolol is available for clinical use as a racemic mixture. Isomer d-nebivolol (SRRR) is a β1 adrenergic receptor blocker and its antipode, l-nebivolol (RSSS) is responsible for endothelium-dependent NO liberation. This report describes the development and validation of a method of analysis of nebivolol isomers in human plasma by high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). Nebivolol isomers were extracted from 2mL aliquots of plasma spiked with tramadol as internal standard, alkalinized and added of sodium chloride and diisopropyl ether:dichloromethane (70:30, v/v). Nebivolol isomers were resolved on a Chirobiotic(®) V column using methanol:acetic acid:diethylamine (100:0.15:0.05, v/v/v) as mobile phase. Protonated ion and respective ion product were monitored in transitions 406>151 for nebivolol and 264>58 for internal standard tramadol. There was no racemization of nebivolol isomers during the procedures of sample preparation and chromatographic analysis and matrix effect was absent. Analysis of nebivolol isomers showed linearity for plasma concentrations of 25-2500pg/mL of each isomer. The quantification limit was 25pg of each isomer/mL of plasma. Variation coefficients and inaccuracy calculated in precision and accuracy determinations were lower than 15%. Nebivolol was stable in human plasma after three successive cycles of freezing and thawing, during 4h at room temperature and after processing during 12h in the auto sampler at 5°C showing deviation values lower than 15%. The method was applied in a study of the kinetic disposition of nebivolol in plasma samples collected until 48h after administration of an oral single dose of 10mg of racemic nebivolol hydrochloride to a patient with systemic arterial hypertension. The clinical study demonstrated that the nebivolol pharmacokinetics is stereoselective. Isomer l-nebivolol showed higher AUC(0-∞) (9.4ng/h/mL vs. 4.7ng/h/mL) and smaller apparent clearance (Cl/f) (531.8L/h vs

  4. Acid-triggered core cross-linked nanomicelles for targeted drug delivery and magnetic resonance imaging in liver cancer cells

    Li X


    Full Text Available Xian Li,1,* Hao Li,2,4,* Wei Yi,3 Jianyu Chen,1 Biling Liang1 1Radiology Department, The Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, People's Republic of China; 2Center of Biomedical Engineering, School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou, People's Republic of China; 3Radiotherapy Department, The First Affiliated Hospital, Guangzhou Medical University, Guangzhou, People's Republic of China; 4School of Engineering, Sun Yat-Sen University, Guangzhou, People's Republic of China *These authors contributed equally to this work Purpose: To research the acid-triggered core cross-linked folate-poly(ethylene glycol-b-poly[N-(N',N'-diisopropylaminoethyl glutamine] (folated-PEG-P[GA-DIP] amphiphilic block copolymer for targeted drug delivery and magnetic resonance imaging (MRI in liver cancer cells. Methods: As an appropriate receptor of protons, the N,N-diisopropyl tertiary amine group (DIP was chosen to conjugate with the side carboxyl groups of poly(ethylene glycol-b-poly (L-glutamic acid to obtain PEG-P(GA-DIP amphiphilic block copolymers. By ultrasonic emulsification, PEG-P(GA-DIP could be self-assembled to form nanosized micelles loading doxorubicin (DOX and superparamagnetic iron oxide nanoparticles (SPIONs in aqueous solution. When PEG-P(GA-DIP nanomicelles were combined with folic acid, the targeted effect of folated-PEG-P(GA-DIP nanomicelles was evident in the fluorescence and MRI results. Results: To further increase the loading efficiency and the cell-uptake of encapsulated drugs (DOX and SPIONs, DIP (pKa≈6.3 groups were linked with ~50% of the side carboxyl groups of poly(L-glutamic acid (PGA, to generate the core cross-linking under neutral or weakly acidic conditions. Under the acidic condition (eg, endosome/lysosome, the carboxyl groups were neutralized to facilitate disassembly of the P(GA-DIP blocks' cross-linking, for duly accelerating the encapsulated drug release. Combined

  5. 水/有机溶剂双相中杏仁醇腈酶促不对称合成(R)-苯乙氰醇%Asymmetric Synthesis of (R)-Mandelonitrile Catalysed by (R)-Oxynitrila se from Almond in Water/Organic Solvent Biphase Systems

    刘森林; 宗敏华; 涂然; 周番


    研究了水/有机溶剂双相中来源于杏仁的(R)-醇腈酶催化苯甲醛与HCN不对称合成(R )-苯乙氰醇,系统探讨了有机溶剂、水相与有机溶剂相体积比、水相pH值和反应温度对反 应速度、转化率和产物光学纯度的影响. 结果表明,上述因素对醇腈酶促不对称合成(R) -苯乙氰醇反应均有显著影响. 异丙醚为该反应最好的有机溶剂,水相与有机溶剂相体积比 以1/2为宜,适宜的pH值为3.4,最佳反应温度为0~5 ℃. 在该优化反应条件下,反应转化率 和产物的光学纯度均高达99%以上.%The asymmetric synthesis of (R)-mandelonitrile from benzaldehyde and hydrog en cyanide using (R)-oxynitrilase from bitter almond in water/organic solve nt biphase systems was studied. The effects of organic solvents, volume ratio of water phase to organic phase, pH value of aqueous phase and reaction temperatur e on the initial reaction rate, the final conversion and enantiomeric purity of the product were explored. All above mentioned facts had important effects on th e reaction. Diisopropyl ether is found to be the best organic solvent for the re action. The optimum volume ratio of water phase to organic phase, pH and reactio n temperature are 1/2, 3.4 and 0~5 ℃ respectively for the reaction. Under the se conditions, both the conversion rate and enantiomeric excess are as high as 99%.

  6. Study on Chemical Constituents of Volatile Oils in Drug Pair of Frankincense and Myrrh by GC-MS%乳香、没药药对配伍挥发油成分的GC-MS分析

    王艳艳; 王团结; 宿树兰; 段金廒; 付小环


    Objective To discuss the influence ot drug compatibility on the components ot the volatile oil in Frankincense and Myrrh. Methods GC-MS system was used to analyze the volatile oil in Frankincense,Myrrh and their combination. The effect of compatibility on the components and content of volatile oil was evaluated. Results The results of GC-MS showed that cadina-1 ( 10 ) ,4-diene, yl-2H-1-Benzopyran, 3,5,6,8 a-tetrahydro-2,5,5,8 a-tetramethyl-, trans- was detectable in Frankincense but was undetectable in the drag pair; Phenol,2-(1,2-dimethyl-2- cyclopenten-l-yl)-, acetate, Naphthalene, 1,2,3,4-tetrahydro-l,6-dimethyl-4 -(1-methylethyl)-,(1 S-cis)-, Azulen-2-ol, 1,4-dimethyl-7-(l-methylethyl)- was detactable in Myrrh but was undectable in the drug pair;1-ethenyl -1-methyl - 2,4-diisopropyl -cyclohexane, 1,2,3,4- tetrahydro-1-methyl -8-Isopropylnaphthalene was dectable in the drug pair but was undetectable in the two single drugs. Conclusion The compatibility of the drug pair has an effect on components and contents in the volatile oil of Frankincense and Myrrh.%目的 考察乳香、没药药对配伍对挥发油化学成分的影响.方法 采用气-质联用系统对乳香、没药药材以及药对配伍中的挥发油进行分析,评价配伍对挥发油成分及含量的影响.结果 采用GC-MS对乳香、没药药材和药对挥发油的成分进行分析比较,发现乳香挥发油中检出的trans-3,5,6,8 a-四氢-2,5,5,8a-四甲基-y1-2H-1-苯并吡喃、荜澄茄-1(10),4-二烯等成分和没药挥发油中检出的2-(1,2-二甲基-2-环戊烯-1-y1)乙酸苯酯、(1S-cis)-1,2,3,4-四氢-1,6-二甲基-4-(1-甲基乙基)-萘、1,4-二甲基-7-(1-甲基乙基)-Azulen-2-醇、(-)-匙叶桉油烯醇等成分在药对挥发油中未检出,而相对于单煎所得的挥发油,药对挥发油中新增成分有1-乙烯基-1-甲基-2,4-二异丙基-环己烷、1,2,3,4-四氢-1-甲基-8-异丙基萘等.结论 乳香、没药药对配伍对所提挥发油的成分和含量都有较大的影响.

  7. Development of methods for the purification of {sup 67}Ga and {sup 68}Ga for biomolecules labeling; Desenvolvimento de metodos de purificacao do {sup 67}Ga e {sup 68}Ga para a marcacao de biomoleculas

    Costa, Renata Ferreira


    diisopropyl ether in XAD 16 and {sup 68}Ga recovery in deionized water. Although the results regarding to {sup 68}Ga recovery and the radiochemical separation between {sup 68}Ga and {sup 65}Zn were excellent, there was no reproducibility on the purification of metals. The most promising and innovative method was the {sup 68}Ga purification performed by cationic resin in basic media, which presented the best results, especially regarding the Zn reduction (98 {+-} 2)%, the chemical contaminant found in great abundance in {sup 68}Ga eluate. The total impurities reduction was (95 {+-} 4)%. The peptides DOTATOC/DOTATATE were labeled {sup 68}Ga in three different forms: purified {sup 68}Ga in basic solution, through solvent extraction and no purified {sup 68}Ga. The best result was achieved with DOTATATE labeling with purified {sup 68}Ga in basic media, proving the purification process efficiency. (author)

  8. Identification and quantification of the migration of chemicals from plastic baby bottles used as substitutes for polycarbonate.

    Simoneau, C; Van den Eede, L; Valzacchi, S


    Community positive list, which means that those should not be found even in the first migration. Such substances included 2,6-di-isopropylnaphthalene (DIPN), found in 4% of the bottles at levels up to 25 µg kg⁻¹, 2,4-di-tert-butyl phenol (in 90% of the bottles at levels up 400 µg kg⁻¹). Moreover, bisphenol A (BPA) was detected and quantified in baby bottles made of PA, but limited to one brand and model specific (but labelled BPA free). Results for baby bottles made of silicone also indicated the presence of components, e.g. potentially coming from inks (benzophenone, diisopropyl naphtahalene - DIPN, which could come for example from the presence of instruction leaflets in the bottles). In the case of silicone, phthalates were also found in relevant concentrations, with levels for DiBP and DBP from the first migration test of 50-150 µg kg⁻¹ and DEHP at levels 25-50 µg kg⁻¹.

  9. Chemical vapour deposition of tungsten oxide thin films from single-source precursors

    Cross, Warren Bradley

    This thesis describes the chemical vapour deposition (CVD) of tungsten oxide thin films on glass from a wide range of single-source precursors. Chapter 1 describes previous work that has motivated this research. Chapter 2 discusses the synthesis of conventional style candidates for single-source precursors. Reactions of WOCl4 with 3-methyl salicylic acid (MesaliH2) and 3,5-di-iso-propyl salicylic acid (di-i-PrsaliH2) yielded the ditungsten complexes [WO(Mesali)(MesaliH)2(mu-O)], 1, and [WO(di-i-Prsali)(di-i-PrsaliH)2(mu-O)], 2, and the monotungsten complex [WO(di-i-Pr sali)(di-i-PrsaliH)Cl], 3. Tungsten(VI) dioxo complexes were prepared by ligand exchange reactions of [WO2(acac)2], 4, yielding [WO2(catH)2], 5, and [WO2(malt)2], 6, (catH2 = 3,5-di-tert-butyl-catechol; maltH = maltol). Chapter 3 describes thermal analyses of the complexes 1 - 6 and tungsten hexaphenoxide, and consequently their suitability for CVD. The use of [W(OPh)6] and 2 - 6 in aerosol assisted CVD is reported in Chapter 4. Brown tungsten oxide was deposited from 2 and 3 at 600 °C; blue partially-reduced WO3-x thin films were deposited from [W(OPh)6] from 300 to 500 °C, from 4 at 600 °C and 6 at 620 °C. Sintering all of the coatings in air at 550 °C afforded yellow films of stoichiometric WO3. Raman spectroscopy and glancing angle XRD showed that coatings deposited from [W(OPh)6] at 300 °C were amorphous, whereas all the other films were the monoclinic phase gamma-tungsten oxide. Taking full advantage of the aerosol vaporisation technique led to the CVD of tungsten oxide films from polyoxometalate single-source precursors, as described in Chapter 5. The isopolyanion [nBu4N]2[W6O19], 7, afforded WO3 at 410 °C; the heteropolyanions [nBu4N]4H3[PW11O39], 8, and [nBu4N]4[PNbW11O40], 9, were used to deposit doped WO3 thin films in a highly-controlled manner at 480 °C. Thus, the unprecedented use of large, charged clusters for CVD was demonstrated. Chapter 6 describes investigations of the

  10. Advanced Extraction Methods for Actinide/Lanthanide Separations

    Scott, M.J.


    high level liquid wastes and a general actinide clean-up procedure. The selectivity of the standard extractant for tetravalent actinides, (N,N-diisobutylcarbamoylmethyl) octylphenylphosphineoxide (CMPO), was markedly improved by the attachment of three CMPO-like functions onto a triphenoxymethane platform, and a ligand that is both highly selective and effective for An(IV) ions was isolated. A 10 fold excess of ligand will remove virtually all of the 4+ actinides from the acidic layer without extracting appreciable quantities of An(III) and Ln(III) unlike simple CMPO ligands. Inspired by the success of the DIAMEX industrial process for extractions, three new tripodal chelates bearing three diglycolamide and thiodiglycolamide units precisely arranged on a triphenoxymethane platform have been synthesized for an highly efficient extraction of trivalent f-element cations from nitric acid media. A single equivalent of ligand will remove 80% of the Ln(III) ion from the acidic layer since the ligand is perfectly suited to accommodate the tricapped trigonal prismatic geometry preferred by the metal center. The ligand is perhaps the most efficient binder available for the heavier lanthanides and due to this unique attribute, the extraction event can be easily followed by 1H NMR spectroscopy confirming the formation of a TPP complex. The most lipophilic di-n-butyl tris-diglycolamide was found to be a significantly weaker extractant in comparison to the di-isopropyl analogs. The tris-thiodiglycolamide derivative proved to be an ineffective chelate for f-elements and demonstrated the importance of the etheric oxygens in the metal binding. The results presented herein clearly demonstrate a cooperative action of these three ligating groups within a single molecule, confirmed by composition and structure of the extracted complexes, and since actinides prefer to have high coordination numbers, the ligands should be particularly adept at binding with three arms. The use of such an