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Sample records for ii experimental methyl

  1. Electronic and optical response of Ru(II) complexes functionalized by methyl, carboxylate groups: joint theoretical and experimental study

    SciTech Connect

    Tretiak, Sergei

    2008-01-01

    New photovoltaic and photocatalysis applications have been recently proposed based on the hybrid Ru(II)-bipyridine-complex/semiconductor quantum dot systems. In order to attach the complex to the surface of a semiconductor, a linking bridge - a carboxyl group - is added to one or two of the 2,2{prime}-bipyridine ligands. Such changes in the ligand structure, indeed, affect electronic and optical properties and consequently, the charge transfer reactivity of Ru-systems. In this study, we apply both theoretical and experimental approaches to analyze the effects brought by functionalization of bipyridine ligands with the methyl, carboxyl, and carboxilate groups on the electronic structure and optical response of the Ru(II) bipyridine complex. First principle calculations based on density functional theory (DFT) and linear response time dependent density functional theory (TDDFT) are used to simulate the ground and excited-state structures of functionalized Ru-complexes in the gas phase, as well as in acetonitrile solution. In addition, an inelaborate Frenkel exciton model is used to explain the optical activity and splitting patterns of the low-energy excited states. All theoretical results nicely complement experimental absorption spectra of Ru-complexes and contribute to their interpretation. We found that the carboxyl group breaks the degeneracy of two low-energy optically bright excited states and red-shifts the absorption spectrum, while leaves ionization and affinity energies of complexes almost unchanged. Experimental studies show a high probability of deprotonation of the carbboxyl group in the Ru-complexes resulted in a slight blue shift and decrease of intensities of the low energy absorption peaks. Comparison of experimental and theoretical linear response spectra of deprotanated complexes demonstrate strong agreement when acetonitrile solvent is used in simulations. A polar solvent is found to play an important role in calculations of optical spectra: it

  2. Theoretical and experimental studies on three new coordination complexes of Co(II), Ni(II), and Cu(II) with 2,4-dichloro-6-{(E)-[(5-chloro-2 sulfanylphenyl)imino]methyl}phenol Schiff base ligand.

    PubMed

    Kusmariya, Brajendra S; Mishra, A P

    2015-11-01

    Three mononuclear coordination complexes of Co(II), Ni(II), and Cu(II) have been synthesized from 2,4-dichloro-6-{(E)-[(5-chloro-2-sulfanylphenyl)imino]methyl}phenol ligand (H 2 L) obtained by simple condensation reaction of 3,5-dichloro-2-hydroxybenzaldehyde and 2-amino-4-chlorobenzenethiol and characterized by elemental analysis, spectral (FT-IR, electronic, and (1)H-NMR), molar conductance, thermal, SEM, PXRD, and fluorescence studies. The PXRD analysis and SEM-EDX micrographs show the crystalline nature of complexes. The domain size and the lattice strain of synthesized compounds have been determined according to Williamson-Hall plot. TG of the synthesized complexes illustrates the general decomposition pattern of the complexes. The ligand exhibits an interesting fluorescence property which is suppressed after complex formation. The Co(II) complex adopted a distorted octahedral configuration while Ni(II) and Cu(II) complexes showed square planar geometry around metal center. The geometry optimization, HOMO-LUMO, molecular electrostatic potential map (MEP), and spin density of synthesized compounds have been performed by density functional theory (DFT) method using B3LYP/6-31G and B3LYP/LANL2DZ as basis set. Graphical abstract Three new coordination complexes of Co(II), Ni(II) and Cu(II) with 2,4-dichloro-6-{(E)-[(5-chloro-2 sulfanylphenyl)imino]methyl}phenol Schiff base ligand. PMID:26438445

  3. Experimental and chemical kinetic modeling study of small methyl esters oxidation: Methyl (E)-2-butenoate and methyl butanoate

    SciTech Connect

    Gail, S.; Sarathy, S.M.; Thomson, M.J.; Dievart, P.; Dagaut, P.

    2008-12-15

    This study examines the effect of unsaturation on the combustion of fatty acid methyl esters (FAME). New experimental results were obtained for the oxidation of methyl (E)-2-butenoate (MC, unsaturated C{sub 4} FAME) and methyl butanoate (MB, saturated C{sub 4} FAME) in a jet-stirred reactor (JSR) at atmospheric pressure under dilute conditions over the temperature range 850-1400 K, and two equivalence ratios ({phi}=0.375,0.75) with a residence time of 0.07 s. The results consist of concentration profiles of the reactants, stable intermediates, and final products, measured by probe sampling followed by on-line and off-line gas chromatography analyses. The oxidation of MC and MB in the JSR and under counterflow diffusion flame conditions was modeled using a new detailed chemical kinetic reaction mechanism (301 species and 1516 reactions) derived from previous schemes proposed in the literature. The laminar counterflow flame and JSR (for {phi}=1.13) experimental results used were from a previous study on the comparison of the combustion of both compounds. Sensitivity analyses and reaction path analyses, based on rates of reaction, were used to interpret the results. The data and the model show that MC has reaction pathways analogous to that of MB under the present conditions. The model of MC oxidation provides a better understanding of the effect of the ester function on combustion, and the effect of unsaturation on the combustion of fatty acid methyl ester compounds typically found in biodiesel. (author)

  4. Experimental test accelerator (ETA) II

    SciTech Connect

    Fessenden, T.J.; Atchison, W.L.; Birx, D.L.

    1981-03-06

    The Experimental Test Accelerator (ETA) is designed to produce a 10 kAmp electron beam at an energy of 4.5 MeV in 40 nsec pulses at an average rate of 2 pps. The accelerator also operates in bursts of 5 pulses spaced by as little as one millisec at an average rate of 5 pps. The machine is currently operating near 80% of its design values and has accumulated over 2.5 million pulses - mostly at a rate of one pps. The plasma cathode electron source, the remainder of the accelerator, and the operating characteristics of the machine are discussed.

  5. Kinetics and mechanism of the mercury(II)-assisted hydrolysis of methyl iodide.

    PubMed

    Celo, Valbona; Scott, Susannah L

    2005-04-01

    The kinetics and mechanism of the reaction of aqueous Hg(II) with methyl iodide have been investigated. The overall reaction is best described as Hg(II)-assisted hydrolysis, resulting in quantitative formation of methanol and, in the presence of excess methyl iodide, ultimately, HgI2 via the intermediate HgI+. The kinetics are biexponential when methyl iodide is in excess. At 25 degrees C, the acceleration provided by Hg2+ is 7.5 times greater than that caused by HgI+, while assistance of hydrolysis was not observed for HgI2. Thus, the reactions are not catalytic in Hg(II). The kinetics are consistent with an SN2-M+ mechanism involving electrophilic attack at iodide. As expected, methylation of mercury is not a reaction pathway; traces of methylmercury(II) are artifacts of the extraction/preconcentration procedure used for methylmercury analysis.

  6. An Experimental and Kinetic Modeling Study of Methyl Decanoate Combustion

    SciTech Connect

    Sarathy, S M; Thomson, M J; Pitz, W J; Lu, T

    2009-12-04

    Biodiesel is a mixture of long chain fatty acid methyl esters derived from fats and oils. This research study presents opposed-flow diffusion flame data for one large fatty acid methyl ester, methyl decanoate, and uses the experiments to validate an improved skeletal mechanism consisting of 648 species and 2998 reactions. The results indicate that methyl decanoate is consumed via abstraction of hydrogen atoms to produce fuel radicals, which lead to the production of alkenes. The ester moiety in methyl decanoate leads to the formation of low molecular weight oxygenated compounds such as carbon monoxide, formaldehyde, and ketene.

  7. Angiotensin II during Experimentally Simulated Central Hypovolemia

    PubMed Central

    Jensen, Theo Walther; Olsen, Niels Vidiendal

    2016-01-01

    Central hypovolemia, defined as diminished blood volume in the heart and pulmonary vascular bed, is still an unresolved problem from a therapeutic point of view. The development of pharmaceutical agents targeted at specific angiotensin II receptors, such as the non-peptidergic AT2-receptor agonist compound 21, is yielding many opportunities to uncover more knowledge about angiotensin II receptor profiles and possible therapeutic use. Cardiovascular, anti-inflammatory, and neuroprotective therapeutic use of compound 21 have been suggested. However, there has not yet been a focus on the use of these agents in a hypovolemic setting. We argue that the latest debates on the effect of angiotensin II during hypovolemia might guide for future studies, investigating the effect of such agents during experimentally simulated central hypovolemia. The purpose of this review is to examine the role of angiotensin II during episodes of central hypovolemia. To examine this, we reviewed results from studies with three experimental models of simulated hypovolemia: head up tilt table test, lower body negative pressure, and hemorrhage of animals. A systemic literature search was made with the use of PubMed/MEDLINE for studies that measured variables of the renin–angiotensin system or its effect during simulated hypovolemia. Twelve articles, using one of the three models, were included and showed a possible organ-protective effect and an effect on the sympathetic system of angiotensin II during hypovolemia. The results support the possible organ-protective vasodilatory role for the AT2-receptor during hypovolemia on both the kidney and the splanchnic tissue. PMID:26973842

  8. An Experimental and Kinetic Modeling Study of Methyl Decanoate Combustion

    SciTech Connect

    Sarathy, S M; Thomson, M J; Pitz, W J; Lu, T

    2010-02-19

    Biodiesel is typically a mixture of long chain fatty acid methyl esters for use in compression ignition engines. Improving biofuel engine performance requires understanding its fundamental combustion properties and the pathways of combustion. This research study presents new combustion data for methyl decanoate in an opposed-flow diffusion flame. An improved detailed chemical kinetic model for methyl decanoate combustion is developed, which serves as the basis for deriving a skeletal mechanism via the direct relation graph method. The novel skeletal mechanism consists of 648 species and 2998 reactions. This mechanism well predicts the methyl decanoate opposed-flow diffusion flame data. The results from the flame simulations indicate that methyl decanoate is consumed via abstraction of hydrogen atoms to produce fuel radicals, which lead to the production of alkenes. The ester moiety in methyl decanoate leads to the formation of low molecular weight oxygenated compounds such as carbon monoxide, formaldehyde, and ketene.

  9. Methyl bromide emissions from a covered field: II. Volatilization

    SciTech Connect

    Yates, S.R.; Gan, J.; Ernst, F.F.

    1996-01-01

    An experiment to investigate the environmental fate and transport of methyl bromide in agricultural fields is described. The methyl bromide volatilization rate was determined as a function of time for conditions where methyl bromide was applied at a rate of 843 kg in a 3.5-ha (i.e., 240 kg/ha) field covered with plastic at a depth of 25 cm. Three methods were used to estimate the methyl bromide volatilization rate, including: the aerodynamic, theoretical profile shape and integrated horizontal flux methods. The highest methyl bromide volatilization rates were at the beginning of the experiment. Within the first 24 h, approximately 36% of the applied methyl bromide mass was lost. Diurnally, the largest volatilization rates occurred during the day when temperatures were high and the atmosphere was unstable. Cooler temperatures, light winds, and neutral to stable atmospheric conditions were present at night, reducing the flux. The total emission calculated using these methods was found to be approximately 64% ({+-} 10%) of the applied mass. A mass balance was calculated using each flux estimation technique and several methods for analyzing the data. The average mass recovery using all the flux methods was 867 kg ({+-}83 kg), which was 102.8% ({+-}9.8%) of the applied (i.e., 843 kg). The range in the mass balance percent (i.e., percent of applied mass that is measured) is from 88 to 112%. The averaged mass balance percent for the aerodynamic method, which involved using the measured data directly, was approximately 100.8%. The total emission calculated using the aerodynamic method was found to be approximately 62% ({+-}11%) of the applied mass. 29 refs., 7 figs., 1 tab.

  10. Experimental factors affecting the robustness of DNA methylation analysis

    PubMed Central

    Pharo, Heidi D.; Honne, Hilde; Vedeld, Hege M.; Dahl, Christina; Andresen, Kim; Liestøl, Knut; Jeanmougin, Marine; Guldberg, Per; Lind, Guro E.

    2016-01-01

    Diverging methylation frequencies are often reported for the same locus in the same disease, underscoring the need for limiting technical variability in DNA methylation analyses. We have investigated seven likely sources of variability at different steps of bisulfite PCR-based DNA methylation analyses using a fully automated quantitative methylation-specific PCR setup of six gene promoters across 20 colon cancer cell lines. Based on >15,000 individual PCRs, all tested parameters affected the normalized percent of methylated reference (PMR) differences, with a fourfold varying magnitude. Additionally, large variations were observed across the six genes analyzed. The highest variation was seen using single-copy genes as reference for normalization, followed by different amounts of template in the PCR, different amounts of DNA in the bisulfite reaction, and storage of bisulfite converted samples. Finally, when a highly standardized pipeline was repeated, the difference in PMR value for the same assay in the same cell line was on average limited to five (on a 0–100 scale). In conclusion, a standardized pipeline is essential for consistent methylation results, where parameters are kept constant for all samples. Nevertheless, a certain level of variation in methylation values must be expected, underscoring the need for careful interpretation of data. PMID:27671843

  11. Mercury(II) and methyl mercury speciation on Streptococcus pyogenes loaded Dowex Optipore SD-2.

    PubMed

    Tuzen, Mustafa; Uluozlu, Ozgur Dogan; Karaman, Isa; Soylak, Mustafa

    2009-09-30

    A solid phase extraction procedure based on speciation of mercury(II) and methyl mercury on Streptococcus pyogenes immobilized on Dowex Optipore SD-2 has been established. Selective and sequential elution with 0.1 mol L(-1) HCl for methyl mercury and 2 mol L(-1) HCl for mercury(II) were performed at pH 8. The determination of mercury levels was performed by cold vapour atomic absorption spectrometry (CVAAS). Optimal analytical conditions including pH, amounts of biosorbent, sample volumes, etc., were investigated. The influences of the some alkaline and earth alkaline ions and some transition metals on the recoveries were also investigated. The capacity of biosorbent for mercury(II) and methyl mercury was 4.8 and 3.4 mg g(-1). The detection limit (3 sigma) of the reagent blank for mercury(II) and methyl mercury was 2.1 and 1.5 ng L(-1). Preconcentration factor was calculated as 25. The relative standard deviations of the procedure were below 7%. The validation of the presented procedure is performed by the analysis of standard reference material (NRCC-DORM 2 Dogfish Muscle). The procedure was successfully applied to the speciation of mercury(II) and methyl mercury in natural water and environmental samples.

  12. Active transport, substrate specificity, and methylation of Hg(II) in anaerobic bacteria

    SciTech Connect

    Schasfer, Jeffra; Rocks, Sara; Zheng, Wang; Liang, Liyuan; Gu, Baohua; Morel, Francois M

    2011-01-01

    The formation of methylmercury (MeHg), which is biomagnified in aquatic food chains and poses a risk to human health, is effected by some iron- and sulfate-reducing bacteria (FeRB and SRB) in anaerobic environments. However, very little is known regarding the mechanism of uptake of inorganic Hg by these organisms, in part because of the inherent difficulty in measuring the intracellular Hg concentration. By using the FeRB Geobacter sulfurreducens and the SRB Desulfovibrio desulfuricans ND132 as model organisms, we demonstrate that Hg(II) uptake occurs by active transport. We also establish that Hg(II) uptake by G. sulfurreducens is highly dependent on the characteristics of the thiols that bind Hg(II) in the external medium, with some thiols promoting uptake and methylation and others inhibiting both. The Hg(II) uptake system of D. desulfuricans has a higher affinity than that of G. sulfurreducens and promotes Hg methylation in the presence of stronger complexing thiols. We observed a tight coupling between Hg methylation and MeHg export from the cell, suggesting that these two processes may serve to avoid the build up and toxicity of cellular Hg. Our results bring up the question of whether cellular Hg uptake is specific for Hg(II) or accidental, occurring via some essential metal importer. Our data also point at Hg(II) complexation by thiols as an important factor controlling Hg methylation in anaerobic environments.

  13. Sensory rhodopsins I and II modulate a methylation/demethylation system in Halobacterium halobium phototaxis

    SciTech Connect

    Spudich, E.N.; Takahashi, T.; Spudich, J.L. )

    1989-10-01

    This work demonstrates that phototaxis stimuli in the archaebacterium Halobacterium halobium control a methylation/demethylation system in vivo through photoactivation of sensory rhodopsin I (SR-I) in either its attractant or repellent signaling form as well as through the repellent receptor sensory rhodopsin II (SR-II, also called phoborhodopsin). The effects of positive stimuli that suppress swimming reversals (i.e., an increase in attractant or decrease in repellent light) and negative stimuli that induce swimming reversals (i.e., a decrease in attractant or increase in repellent light) through each photoreceptor were monitored by assaying release of volatile (3H)methyl groups. This assay has been used to measure (3H)methanol produced during the process of adaptation to chemotactic stimuli in eubacteria. In H. halobium positive photostimuli produce a transient increase in the rate of demethylation followed by a decrease below the unstimulated value, whereas negative photostimuli cause an increase followed by a rate similar to that of the unstimulated value. Photoactivation of the SR-I attractant and simultaneous photoactivation of the SR-II repellent receptors cancel in their effects on demethylation, demonstrating the methylation system is regulated by an integrated signal. Analysis of mutants indicates that the source for the volatile methyl groups is intrinsic membrane proteins distinct from the chromoproteins that share the membrane. A methyl-accepting protein (94 kDa) previously correlated in amount with the SR-I chromoprotein (25 kDa) is shown here to be missing in a recently isolated SR-I-SR-II+ mutant (Flx3b), thus confirming the association of this protein with SR-I. Photoactivated SR-II in mutant Flx3b controls demethylation, predicting the existence of a photomodulated methyl-accepting component distinct from the 94-kDa protein of SR-I.

  14. Mercury Methylation by HgcA: Theory Supports Carbanion Transfer to Hg(II)

    SciTech Connect

    Zhou, Jing; Riccardi, Demian M; Beste, Ariana; Smith, Jeremy C; Parks, Jerry M

    2014-01-01

    Many proteins use corrinoid cofactors to facilitate methyl transfer reactions. Recently, a corrinoid protein, HgcA, has been shown to be required for the production of the neurotoxin methylmercury by anaerobic bacteria. A strictly conserved Cys residue in HgcA was predicted to be a lower-axial ligand to Co(III), which has never been observed in a corrinoid protein. Here, we use density functional theory to study homolytic and heterolytic Co-C bond dissociation and methyl transfer to Hg(II) substrates with model methylcobalamin complexes containing a lower-axial Cys or His ligand to cobalt, the latter of which is commonly found in other corrinoid proteins. We find that Cys thiolate coordination to Co facilitates both methyl radical and methyl carbanion transfer to Hg(II) substrates, but carbanion transfer is more favorable overall in the condensed phase. Thus, our findings are consistent with HgcA representing a new class of corrinoid protein capable of transferring methyl groups to electrophilic substrates.

  15. Promoter CpG island methylation of RET predicts poor prognosis in stage II colorectal cancer patients.

    PubMed

    Draht, Muriel X G; Smits, Kim M; Tournier, Benjamin; Jooste, Valerie; Chapusot, Caroline; Carvalho, Beatriz; Cleven, Arjen H G; Derks, Sarah; Wouters, Kim A D; Belt, Eric J T; Stockmann, Hein B A C; Bril, Herman; Weijenberg, Matty P; van den Brandt, Piet A; de Bruïne, Adriaan P; Herman, James G; Meijer, Gerrit A; Piard, Françoise; Melotte, Veerle; van Engeland, Manon

    2014-05-01

    Improved prognostic stratification of patients with TNM stage II colorectal cancer (CRC) is desired, since 20-30% of high-risk stage II patients may die within five years of diagnosis. This study was conducted to investigate REarranged during Transfection (RET) gene promoter CpG island methylation as a possible prognostic marker for TNM stage II CRC patients. The utility of RET promoter CpG island methylation in tumors of stage II CRC patients as a prognostic biomarker for CRC related death was studied in three independent series (including 233, 231, and 294 TNM stage II patients, respectively) by using MSP and pyrosequencing. The prognostic value of RET promoter CpG island methylation was analyzed by using Cox regression analysis. In the first series, analyzed by MSP, CRC stage II patients (n = 233) with RET methylated tumors had a significantly worse overall survival as compared to those with unmethylated tumors (HRmultivariable = 2.51, 95%-CI: 1.42-4.43). Despite a significant prognostic effect of RET methylation in stage III patients of a second series, analyzed by MSP, the prognostic effect in stage II patients (n = 231) was not statistically significant (HRmultivariable = 1.16, 95%-CI 0.71-1.92). The third series (n = 294), analyzed by pyrosequencing, confirmed a statistically significant association between RET methylation and poor overall survival in stage II patients (HRmultivariable = 1.91, 95%-CI: 1.04-3.53). Our results show that RET promoter CpG island methylation, analyzed by two different techniques, is associated with a poor prognosis in stage II CRC in two independent series and a poor prognosis in stage III CRC in one series. RET methylation may serve as a useful and robust tool for clinical practice to identify high-risk stage II CRC patients with a poor prognosis. This merits further investigation. PMID:24560444

  16. Sulfamates of methyl triterpenoates are effective and competitive inhibitors of carbonic anhydrase II.

    PubMed

    Schwarz, Stefan; Sommerwerk, Sven; Lucas, Susana D; Heller, Lucie; Csuk, René

    2014-10-30

    Carbonic anhydrase II, belonging to one of the most important enzyme groups of the human body, is a well-studied isozyme from the family of the carbonic anhydrases. Since it is involved in several physiological processes, it has been a pharmaceutical target for many years. In this study we synthesized a number of sulfamates derived from pentacyclic methyl triterpenoates, and we demonstrate their potential as carbonic anhydrase II inhibitors using the well-established photometric 4-nitrophenyl acetate assay. Inhibition constants, as an indicator of their inhibition strength, were in the micromolar range; one compound (10, methyl (3β) 3-(aminosulfonyloxy)-oleanoate) showed a Ki value as low as 0.3 μM. This Ki value is comparable to that of acetazolamide which is a potent carbonic anhydrase inhibitor and a drug for the treatment of glaucoma.

  17. Methyl Halide Emissions From Experimental Fires With Southern African Biofuels

    NASA Astrophysics Data System (ADS)

    Lobert, J. M.; Lobert, J. M.; Keene, W. C.; Crutzen, P. J.; Scharffe, D. H.; Maben, J. R.; Williams, J.

    2001-12-01

    Under the auspices of SAFARI 2000, biofuels (savanna grasses, shrubs, woody plants, litter, agricultural waste, and charcoal) were sampled in the savannah of Kruger National Park, the Kalahari of Etosha National Park and the Miombo woodlands in Zambia and Malawi. More than 50 sub-samples were burned in 60 experiments under semi-controlled conditions at the biomass burning facility of the Max Planck Institute for Chemistry in Mainz, Germany. Emissions were sampled with flasks and analyzed by GC-MS for gaseous CH3Br, CH3Cl, CH3I and other halogenated compounds. The elemental compositions of the fuel and ash from each burn were also measured. Molar emission ratios of these compounds relative to CO, CO2 and the elemental composition of the fuel as well as partial mass balances for carbon, nitrogen and halogens will be presented with emphasis on methyl halide emissions. These results will be compared to similar data in the literature and preliminary estimates for the impacts of biomass burning on regional and global budgets will be presented. Additional resources can be found at: http://jurgenlobert.org/projects/mpi_safari/ and http://safari.gecp.virginia.edu/

  18. Experimental and Kinetic Modeling Study of Extinction and Ignition of Methyl Decanoate in Laminar Nonpremixed Flows

    SciTech Connect

    Seshadri, K; Lu, T; Herbinet, O; Humer, S; Niemann, U; Pitz, W J; Law, C K

    2008-01-09

    Methyl decanoate is a large methyl ester that can be used as a surrogate for biodiesel. In this experimental and computational study, the combustion of methyl decanoate is investigated in nonpremixed, nonuniform flows. Experiments are performed employing the counterflow configuration with a fuel stream made up of vaporized methyl decanoate and nitrogen, and an oxidizer stream of air. The mass fraction of fuel in the fuel stream is measured as a function of the strain rate at extinction, and critical conditions of ignition are measured in terms of the temperature of the oxidizer stream as a function of the strain rate. It is not possible to use a fully detailed mechanism for methyl decanoate to simulate the counterflow flames because the number of species and reactions is too large to employ with current flame codes and computer resources. Therefore a skeletal mechanism was deduced from a detailed mechanism of 8555 elementary reactions and 3036 species using 'directed relation graph' method. This skeletal mechanism has only 713 elementary reactions and 125 species. Critical conditions of ignition were calculated using this skeletal mechanism and are found to agree well with experimental data. The predicted strain rate at extinction is found to be lower than the measurements. In general, the methyl decanoate mechanism provides a realistic kinetic tool for simulation of biodiesel fuels.

  19. Synthesis of poly(aminopropyl/methyl)silsesquioxane particles as effective Cu(II) and Pb(II) adsorbents.

    PubMed

    Lu, Xin; Yin, Qiangfeng; Xin, Zhong; Li, Yang; Han, Ting

    2011-11-30

    Poly(aminopropyl/methyl)silsesquioxane (PAMSQ) particles have been synthesized by a one-step hydrolytic co-condensation process using 3-aminopropyltriethoxysilane (APTES) and methyltrimethoxysilane (MTMS) as precursors in the presence of base catalyst in aqueous medium. The amino functionalities of the particles could be controlled by adjusting the organosilanes feed ratio. The compositions of the amino-functionalized polysilsesquioxanes were confirmed by FT-IR spectroscopy, solid-state (29)Si NMR spectroscopy, and elemental analysis. The strong adsorbability of Cu(II) and Pb(II) ions onto PAMSQ particles was systematically examined. The effect of adsorption time, initial metal ions concentration and pH of solutions was studied to optimize the metal ions adsorbability of PAMSQ particles. The kinetic studies indicated that the adsorption process well fits the pseudo-second-order kinetics. Adsorption phenomena appeared to follow Langmuir isotherm. The PAMSQ particles demonstrate the highest Cu(II) and Pb(II) adsorption capacity of 2.29 mmol/g and 1.31 mmol/g at an initial metal ions concentration of 20mM, respectively. The PAMSQ particles demonstrate a promising application in the removal of Cu(II) and Pb(II) ions from aqueous solutions. PMID:21945683

  20. Ni/sup II/(dioxo(16)aneN/sub 5/)-induced methane formation from methyl coenzyme M

    SciTech Connect

    Drain, C.M.; Sable, D.B.; Corden, B.B.

    1988-07-13

    A mechanism has been previously proposed for methyl-coenzyme M (H/sub 3/CSCH/sub 2/CH/sub 2/SO/sub 3//sup /minus//) reductase where Ni/sup II/F/sub 430/ is first reduced to NiF/sub 430/, which homolytically cleaves the methyl-coenzyme M to produce methyl-Ni/sup I/F/sub 430/ followed by the protonation of methyl-Ni/sup I/F/sub 430/ to yield CH/sub 4/ and Ni/sup II/F/sub 430/. The role of the nickel ion oxidation state in methyl-coenzyme M catalysis has been examined. It was found that both the mono- and divalent oxidation states of the water soluble Ni (dioxo(16)-aneN/sub 5/), NiL, complex catalyze the methyl-coenzyme M to methane and coenzyme M. Some aqueous solutions of other nickel compounds, e.g. nickel (II) acetate, nickel(II) tetraethylenepentamine, or nickel(II) 1,4,8,11-tetraazacyclotetradecane-5,7-dione, do not convert methyl-coenzyme M to methane under argon or hydrogen. 30 references, 1 figure.

  1. Epigenetic Methylation of Parathyroid CaR and VDR Promoters in Experimental Secondary Hyperparathyroidism.

    PubMed

    Hofman-Bang, Jacob; Gravesen, Eva; Olgaard, Klaus; Lewin, Ewa

    2012-01-01

    Secondary hyperparathyroidism (s-HPT) in uremia is characterized by decreased expression in the parathyroids of calcium sensing (CaR) and vitamin D receptors (VDR). Parathyroid hormone (PTH) is normalized despite low levels of CaR and VDR after experimental reversal of uremia. The expression of CaR in parathyroid cultures decreases rapidly. Methylation of promoter regions is often detected during epigenetic downregulation of gene expression. Therefore, using an experimental rat model, we examined changes in methylation levels of parathyroid CaR and VDR promoters in vivo and in vitro. Methods. Uremia was induced by 5/6 nephrectomy. Melting temperature profiling of CaR and VDR PCR products after bisulfite treatment of genomic DNA from rat parathyroids was performed. Real-time PCR measured expression of PTH, CaR, VDR, and klotho genes in vitro. Results. Parathyroids from uremic rats had similar low levels of methylation in vivo and in vitro. In culture, a significant downregulation of CaR, VDR, and klotho within two hours of incubation was observed, while housekeeping genes remained stable for 24 hours. Conclusion. In uremic s-HPT and in vitro, no overall changes in methylation levels in the promoter regions of parathyroid CaR and VDR genes were found. Thus, epigenetic methylation of these promoters does not explain decreased parathyroid expression of CaR and VDR genes in uremic s-HPT.

  2. Growth and characterization of diaquatetrakis (thiocyanato) cobalt (II) mercury (II) N-methyl-2-pyrolidone (CMTWMP) single crystals

    NASA Astrophysics Data System (ADS)

    Potheher, I. Vetha; Madhavan, J.; Rajarajan, K.; Nagaraja, K. S.; Sagayaraj, P.

    2008-01-01

    Single crystals of diaquatetrakis (thiocyanato) cobalt (II) mercury (II) N-methyl-2-pyrolidone, (CoHg(SCN) 4·(H 2O) 2·2(C 3H 6CONCH 3) (abbreviated as CMTWMP) were grown using slow solvent evaporation technique. The structure of the grown crystals was confirmed by single-crystal X-ray diffraction (XRD) technique. The optical properties of the crystals were investigated by Fourier transform infrared (FTIR) and UV-Vis-NIR transmission spectra. The grown crystals of CMTWMP were also subjected to dielectric, photoconductivity, thermal and microhardness studies. The photoconductivity study of CMTWMP confirms the electrochromism behaviour in the sample. The SHG efficiency of the sample was measured by Kurtz and Perry powder technique and its value is almost comparable with KDP.

  3. Rapid Photodegradation of Methyl Orange (MO) Assisted with Cu(II) and Tartaric Acid.

    PubMed

    Guo, Jing; Chen, Xue; Shi, Ying; Lan, Yeqing; Qin, Chao

    2015-01-01

    Cu(II) and organic carboxylic acids, existing extensively in soil and aquatic environments, can form complexes that may play an important role in the photodegradation of organic contaminants. In this paper, the catalytic role of Cu(II) in the removal of methyl orange (MO) in the presence of tartaric acid with light was investigated through batch experiments. The results demonstrate that the introduction of Cu(II) could markedly enhance the photodegradation of MO. In addition, high initial concentrations of Cu(II) and tartaric acid benefited the decomposition of MO. The most rapid removal of MO assisted by Cu(II) was achieved at pH 3. The formation of Cu(II)-tartaric acid complexes was assumed to be the key factor, generating hydroxyl radicals (•OH) and other oxidizing free radicals under irradiation through a ligand-to-metal charge-transfer pathway that was responsible for the efficient degradation of MO. Some intermediates in the reaction system were also detected to support this reaction mechanism.

  4. Rapid Photodegradation of Methyl Orange (MO) Assisted with Cu(II) and Tartaric Acid

    PubMed Central

    Guo, Jing; Chen, Xue; Shi, Ying; Lan, Yeqing; Qin, Chao

    2015-01-01

    Cu(II) and organic carboxylic acids, existing extensively in soil and aquatic environments, can form complexes that may play an important role in the photodegradation of organic contaminants. In this paper, the catalytic role of Cu(II) in the removal of methyl orange (MO) in the presence of tartaric acid with light was investigated through batch experiments. The results demonstrate that the introduction of Cu(II) could markedly enhance the photodegradation of MO. In addition, high initial concentrations of Cu(II) and tartaric acid benefited the decomposition of MO. The most rapid removal of MO assisted by Cu(II) was achieved at pH 3. The formation of Cu(II)-tartaric acid complexes was assumed to be the key factor, generating hydroxyl radicals (•OH) and other oxidizing free radicals under irradiation through a ligand-to-metal charge-transfer pathway that was responsible for the efficient degradation of MO. Some intermediates in the reaction system were also detected to support this reaction mechanism. PMID:26241043

  5. Disodium diaqua-bis-(methyl-enedi-phos-pho-nato-κO,O')cobaltate(II) dihydrate.

    PubMed

    van Merwe, Kina; Visser, Hendrik G; Venter, Johan A

    2011-10-01

    In the title compound, Na(2)[Co(CH(4)O(6)P(2))(2)(H(2)O)(2)]·2H(2)O, the asymmetric unit is composed of one methyl-enediphospho-nate ligand and one water mol-ecule, which both are coordinated to a Co(II) atom, as well as a non-coordinated water mol-ecule and a sodium cation. The Co(II) atom occupies a special position on a crystallographic inversion centre. The slightly distorted Co(II)O(6) octa-hedral coordination environment is composed of two bidentate methyl-enediphospho-nate ligands and two coordinated water mol-ecules in trans positions. The sodium ion is octa-hedrally coordinated to six O atoms with Na-O distances ranging from 2.3149 (12) to 2.6243 (12) Å. An extensive three-dimensional network of inter-molecular as well as intra-molecular O-H⋯O and C-H⋯O hydrogen bonding inter-acions is present. PMID:22058722

  6. Experimental study of the oxidation of methyl oleate in a jet-stirred reactor

    SciTech Connect

    Bax, Sarah; Hakka, Mohammed Hichem; Glaude, Pierre-Alexandre; Herbinet, Olivier; Battin-Leclerc, Frederique

    2010-06-15

    The experimental study of the oxidation of a blend containing n-decane and a large unsaturated ester, methyl oleate, was performed in a jet-stirred reactor over a wide range of temperature covering both low and high temperature regions (550-1100 K), at a residence time of 1.5 s, at quasi atmospheric pressure with high dilution in helium (n-decane and methyl oleate inlet mole fractions of 1.48 x 10{sup -3} and 5.2 x 10{sup -4}) and under stoichiometric conditions. The formation of numerous reaction products was observed. At low and intermediate temperatures, the oxidation of the blend led to the formation of species containing oxygen atoms like cyclic ethers, aldehydes and ketones deriving from n-decane and methyl oleate. At higher temperature, these species were not formed anymore and the presence of unsaturated species was observed. Because of the presence of the double bond in the middle of the alkyl chain of methyl oleate, the formation of some specific products was observed. These species are dienes and esters with two double bonds produced from the decomposition paths of methyl oleate and some species obtained from the addition of H-atoms, OH and HO{sub 2} radicals to the double bond. Experimental results were compared with former results of the oxidation of a blend of n-decane and methyl palmitate performed under similar conditions. This comparison allowed highlighting the similarities and the differences in the reactivity and in the distribution of the reaction products for the oxidation of large saturated and unsaturated esters. (author)

  7. A fluorescence method for detection of DNA and DNA methylation based on graphene oxide and restriction endonuclease HpaII.

    PubMed

    Wei, Wei; Gao, Chunyan; Xiong, Yanxiang; Zhang, Yuanjian; Liu, Songqin; Pu, Yuepu

    2015-01-01

    DNA methylation plays an important role in many biological events and is associated with various diseases. Most traditional methods for detection of DNA methylation are based on the complex and expensive bisulfite method. In this paper, we report a novel fluorescence method to detect DNA and DNA methylation based on graphene oxide (GO) and restriction endonuclease HpaII. The skillfully designed probe DNA labeled with 5-carboxyfluorescein (FAM) and optimized GO concentration keep the probe/target DNA still adsorbed on the GO. After the cleavage action of HpaII the labeled FAM is released from the GO surface and its fluorescence recovers, which could be used to detect DNA in the linear range of 50 pM-50 nM with a detection limit of 43 pM. DNA methylation induced by transmethylase (Mtase) or other chemical reagents prevents HpaII from recognizing and cleaving the specific site; as a result, fluorescence cannot recover. The fluorescence recovery efficiency is closely related to the DNA methylation level, which can be used to detect DNA methylation by comparing it with the fluorescence in the presence of intact target DNA. The method for detection of DNA and DNA methylation is simple, reliable and accurate.

  8. Poly[(μ(3)-camphorato-κO:O':O'')(2-methyl-1H-imidazole-κN)zinc(II)].

    PubMed

    Shi, Haochen; Li, Chunjie; Gao, Feng; Chen, Jingyan; Han, Fei

    2010-03-03

    In the title compound, [Zn(C(10)H(14)O(4))(C(4)H(6)N(2))](n), each Zn(II) ion is coordinated by one N atom from one 2-methyl-1H-imidazole ligand and three O atoms from two camphorate (cap) ligands in a distorted tetra-hedral geometry. In one of the cap ligands, one methyl group is disordered between positions 1 and 3 in a 0.518 (12):0.482 (12) ratio. Each cap ligand bridges three Zn(II) ions, forming two-dimensional layers, which inter-act further via N-H⋯O hydrogen bonds.

  9. Photoreduction of methyl viologen mediated by tris(bipyridyl)ruthenium(II) in inert colloidal suspensions

    SciTech Connect

    Kelly, L.A.; Rodgers, M.A.J. )

    1994-06-23

    The photoreduction of methyl viologen, covalently attached to a tris(bipyridyl)ruthenium(II) chromophore, in suspensions of positively charged alumina-coated colloidal silica particles, via N-phenylglycine electron donor, is reported. In the tris(bipyridyl)ruthenium(II) complexes, the central metal atom is coordinated to two 4,4[prime]-dicarboxy-2,2[prime]-bipyridine ligands and thus carries a net 2-charge at pH 5.0. Coadsorption of the N-phenylglycine and ruthenium chromophore to the colloidal particles results in rapid production of reduced viologen following visible laser flash excitation of the tris(bipyridyl)ruthenium(II) complex. The yield of the radical was dependent upon the concentration of the electron donor added to the system, but its multiphasic decay was independent of both the N-phenylglycine concentration and the initial concentration of viologen radical cation. Furthermore, both the yield and decay kinetics of the viologen radical cation were relatively independent of the number of intervening methylene units between the ruthenium complex and viologen electron acceptor. 18 refs., 5 figs., 2 tabs.

  10. Cigarette smoke extract induces aberrant cytochrome-c oxidase subunit II methylation and apoptosis in human umbilical vascular endothelial cells.

    PubMed

    Yang, Min; Chen, Ping; Peng, Hong; Zhang, Hongliang; Chen, Yan; Cai, Shan; Lu, Qianjin; Guan, Chaxiang

    2015-03-01

    Cigarette smoke-induced apoptosis of vascular endothelial cells contributes to the pathogenesis of chronic obstructive pulmonary disease. However, the mechanisms responsible for endothelial apoptosis remain poorly understood. We conducted an in vitro study to investigate whether DNA methylation is involved in smoking-induced endothelial apoptosis. Human umbilical vascular endothelial cells (HUVECs) were exposed to cigarette smoke extract (CSE) at a range of concentrations (0-10%). HUVECs were also incubated with a demethylating reagent, 5-aza-2'-deoxycytidinem (AZA), with and without CSE. Apoptosis was assessed by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay and flow cytometry using annexin V-FITC/propidium iodide staining. We found that CSE treatment significantly increased HUVEC apoptosis in a dose- and time-dependent manner. Quantitative real-time RT-PCR and immunoblot revealed that CSE treatment decreased cytochrome-c oxidase subunit II (COX II) mRNA and protein levels and decreased COX activity. Methylation-specific PCR and direct bisulfite sequencing revealed positive COX II gene methylation. AZA administration partly increased mRNA and protein expressions of COX II, and COX activity decreased by CSE and attenuated the toxic effects of CSE. Our results showed that CSE induced aberrant COX II methylation and apoptosis in HUVECs. PMID:25500741

  11. Methylation of RNA polymerase II non-consensus Lysine residues marks early transcription in mammalian cells

    PubMed Central

    Dias, João D; Rito, Tiago; Torlai Triglia, Elena; Kukalev, Alexander; Ferrai, Carmelo; Chotalia, Mita; Brookes, Emily; Kimura, Hiroshi; Pombo, Ana

    2015-01-01

    Dynamic post-translational modification of RNA polymerase II (RNAPII) coordinates the co-transcriptional recruitment of enzymatic complexes that regulate chromatin states and processing of nascent RNA. Extensive phosphorylation of serine residues at the largest RNAPII subunit occurs at its structurally-disordered C-terminal domain (CTD), which is composed of multiple heptapeptide repeats with consensus sequence Y1-S2-P3-T4-S5-P6-S7. Serine-5 and Serine-7 phosphorylation mark transcription initiation, whereas Serine-2 phosphorylation coincides with productive elongation. In vertebrates, the CTD has eight non-canonical substitutions of Serine-7 into Lysine-7, which can be acetylated (K7ac). Here, we describe mono- and di-methylation of CTD Lysine-7 residues (K7me1 and K7me2). K7me1 and K7me2 are observed during the earliest transcription stages and precede or accompany Serine-5 and Serine-7 phosphorylation. In contrast, K7ac is associated with RNAPII elongation, Serine-2 phosphorylation and mRNA expression. We identify an unexpected balance between RNAPII K7 methylation and acetylation at gene promoters, which fine-tunes gene expression levels. DOI: http://dx.doi.org/10.7554/eLife.11215.001 PMID:26687004

  12. Dicaesium diaqua-bis-(methyl-ene-diphospho-nato-κO,O')cobaltate(II).

    PubMed

    van Merwe, Kina; Visser, Hendrik G; Venter, Johan A

    2011-10-01

    The asymmetric unit of the title compound, Cs(2)[Co(CH(4)O(6)P(2))(2)(H(2)O)(2)], is comprised of one bidentate methyl-enediphospho-nate ligand and one water mol-ecule which are coordinated to the Co(II) atom, as well as a caesium counter-cation. The Co atom occupies a special position on a crystallographic inversion center. The caesium ion is octa-hedrally coordinated by six O atoms with Cs-O distances ranging from 3.119 (2) to 3.296 (2) Å. A three-dimensional network is formed through O-H⋯O hydrogen bonds. PMID:22065711

  13. Experimental Stark Shift of Some Xe II UV Lines

    SciTech Connect

    Djurovic, S.; Cirisan, M.; Pelaez, R. J.; Aparicio, J. A.; Mar, S.

    2008-10-22

    Stark broadening and shift of Xe II lines have been the subject of many experimental and theoretical studie. Here, the results of Stark shift measurements for six Xe II lines are presented. All given results are here reported for the first time. Two lines belong to 5d-6p, two to 5d-7p and one to 5d-4f transition. In this experiment pulsed arc plasma made of mixture of 95% helium and 5% xenon was used. Measured electron densities and temperatures were in the range of (0.2-1.8)10{sup 23}m{sup -3} and 18300-25500 K respectively.

  14. Detection of experimentally produced acute pulmonary arterial occlusion by methyl iodide-131 inhalation imaging

    SciTech Connect

    Grossman, Z.D.; McAfee, J.G.; Subramanian, G.

    1981-08-01

    Methyl iodide-131 (CH/sub 3/I-131) is described as an agent for detection of acute experimentally produced pulmonary arterial occlusion in dogs. When gaseous CH/sub 3/I-131 is inhaled, radioactivity passes instantaneously from the alveoli to the lung capillary bed. Where pulmonary blood flow exists, activity is washed out into the systemic circulation, but in areas of blood stasis, a transient pulmonary hot spot remains. CH/sub 3/I-131 is easily produced and inexpensive, but administration is awkward and strict radiation safety precautions are mandatory.

  15. Gas Atomization of Amorphous Aluminum Powder: Part II. Experimental Investigation

    NASA Astrophysics Data System (ADS)

    Zheng, Baolong; Lin, Yaojun; Zhou, Yizhang; Lavernia, Enrique J.

    2009-12-01

    The optimal processing parameters that are required to atomize amorphous Al were established on the basis of numerical simulations in part I of this study. In this part II, the characterization of cooling rate experienced by gas-atomized, Al-based amorphous powders was studied via experiments. An experimental investigation was implemented to validate the numerical predictions reported in part I of this study. The cooling rate experienced by the powders, for example, was experimentally determined on the basis of dendrite arm spacing correlations, and the results were compared with the numerical predictions. The experimental studies were completed using commercial Al 2024 as a baseline material and Al90Gd7Ni2Fe1 metallic glass (MG). The results showed that the cooling rate of droplets increases with decreasing particle size, with an increasing proportion of helium in the atomization gas and with increasing melt superheat. The experimental results reported in this article suggest good agreement between experiments and numerical simulations.

  16. (1) H NMR analysis of O-methyl-inositol isomers: a joint experimental and theoretical study.

    PubMed

    De Almeida, Mauro V; Couri, Mara Rubia C; De Assis, João Vitor; Anconi, Cleber P A; Dos Santos, Hélio F; De Almeida, Wagner B

    2012-09-01

    Density functional theory (DFT) calculations of (1) H NMR chemical shifts for l-quebrachitol isomers were performed using the B3LYP functional employing the 6-31G(d,p) and 6-311 + G(2d,p) basis sets. The effect of the solvent on the B3LYP-calculated NMR spectrum was accounted for using the polarizable continuum model. Comparison is made with experimental (1) H NMR spectroscopic data, which shed light on the average uncertainty present in DFT calculations of chemical shifts and showed that the best match between experimental and theoretical B3LYP (1) H NMR profiles is a good strategy to assign the molecular structure present in the sample handled in the experimental measurements. Among four plausible O-methyl-inositol isomers, the l-quebrachitol 2a structure was unambiguously assigned based only on the comparative analysis of experimental and theoretical (1) H NMR chemical shift data. The B3LYP infrared (IR) spectrum was also calculated for the four isomers and compared with the experimental data, with analysis of the theoretical IR profiles corroborating assignment of the 2a structure. Therefore, it is confirmed in this study that a combined experimental/DFT spectroscopic investigation is a powerful tool in structural/conformational analysis studies. PMID:22865668

  17. (1) H NMR analysis of O-methyl-inositol isomers: a joint experimental and theoretical study.

    PubMed

    De Almeida, Mauro V; Couri, Mara Rubia C; De Assis, João Vitor; Anconi, Cleber P A; Dos Santos, Hélio F; De Almeida, Wagner B

    2012-09-01

    Density functional theory (DFT) calculations of (1) H NMR chemical shifts for l-quebrachitol isomers were performed using the B3LYP functional employing the 6-31G(d,p) and 6-311 + G(2d,p) basis sets. The effect of the solvent on the B3LYP-calculated NMR spectrum was accounted for using the polarizable continuum model. Comparison is made with experimental (1) H NMR spectroscopic data, which shed light on the average uncertainty present in DFT calculations of chemical shifts and showed that the best match between experimental and theoretical B3LYP (1) H NMR profiles is a good strategy to assign the molecular structure present in the sample handled in the experimental measurements. Among four plausible O-methyl-inositol isomers, the l-quebrachitol 2a structure was unambiguously assigned based only on the comparative analysis of experimental and theoretical (1) H NMR chemical shift data. The B3LYP infrared (IR) spectrum was also calculated for the four isomers and compared with the experimental data, with analysis of the theoretical IR profiles corroborating assignment of the 2a structure. Therefore, it is confirmed in this study that a combined experimental/DFT spectroscopic investigation is a powerful tool in structural/conformational analysis studies.

  18. The rise and fall of mercury methylation in an experimental reservoir.

    PubMed

    St Louis, Vincent L; Rudd, John W M; Kelly, Carol A; Bodaly, R A Drew; Paterson, Michael J; Beaty, Kenneth G; Hesslein, Raymond H; Heyes, Andrew; Majewski, Andrew R

    2004-03-01

    For the past 9 years, we experimentally flooded a wetland complex (peatland surrounding an open water pond) at the Experimental Lakes Area (ELA), northwestern Ontario, Canada, to examine the biogeochemical cycling of methyl mercury (MeHg) in reservoirs. Using input-output budgets, we found that prior to flooding, the wetland complex was a net source of approximately 1.7 mg MeHg ha(-1) yr(-1) to downstream ecosystems. In the first year of flooding, net yields of MeHg from the reservoir increased 40-fold to approximately 70 mg MeHg ha(-1) yr(-1). Subsequently, annual net yields of MeHg from the reservoir declined (10-50 mg MeHg ha(-1) yr(-1)) but have remained well above natural levels. The magnitude and timing of Hg methylation in the flooded peat portion of the wetland reservoir were very different than in the open water region of the reservoir. In terms of magnitude, net Hg methylation rates in the peat in the first 2 years of flooding were 2700 mg ha(-1) yr(-1), constituting over 97% of the MeHg produced at the whole-ecosystem level. But in the following 3 years, there was a large decrease in the mass of MeHg in the flooded peat due to microbial demethylation. In contrast, concentrations of MeHg in the open water region and in zooplankton, and body burdens of Hg in cyprinid fish, remained high for the full 9 years of this study. Microbial activity in the open water region also remained high, as evidenced by continued high concentrations of dissolved CO2 and CH4. Thus, the large short-term accumulation of MeHg mass in the peat appeared to have only a small influence on concentrations of MeHg in the biota; rather MeHg accumulation in biota was sustained by the comparatively small ongoing net methylation of Hg in the flooded pond where microbial activity remained high. In large reservoirs, where the effects of wind and fetch are greater than in the small experimental reservoir we constructed, differences can occur in the timing and extent of peat and soil erosion

  19. Ultraviolet spectrophotometric characterization of copper(II) complexes with imidazole N-methyl derivatives of ?-histidine in aqueous solution

    NASA Astrophysics Data System (ADS)

    Prenesti, Enrico; Berto, Silvia; Daniele, Pier Giuseppe

    2003-01-01

    In this study we considered π-methyl- L-histidine (π-methis) and τ-methyl- L-histidine (τ-methis) as ligands for copper(II) ion, in order to clarify, by means of ultraviolet (UV) spectroscopy in aqueous solution ( T=25 °C, I=0.1 M), some aspects of the co-ordination mode with respect to other ligands of a previous study in which copper(II) complexes of L-histidine, N-acetyl- L-histidine, histamine, L-histidine methyl ester or carnosine were investigated. Particularly, UV spectra (300-400 nm) were recorded on solutions at various pH values, containing each binary system Cu-L; afterwards, an UV absorption spectrum for single complexes was calculated, taking into account the chemical model previously assessed, in order to fulfil a correct spectrum-structure correlation. The problem related to the eventual superimposition of the CT shoulder (≈330 nm) to copper(II) of OH - and imidazole pyridine nitrogen groups were now solved by means of a comparison of the UV spectra of dimer species formed by both π-methis or τ-methis. Finally, copper(II) complex formation with 2,2'-bipyridine was taken into account to compare the behaviour of pyridine (from 2,2'-bipyridine) and pyridine imidazole nitrogens (from π-methis or τ-methis) with respect to the UV charge transfer process to copper(II) ion.

  20. Experimental and computational thermochemical study of 2- and 3-thiopheneacetic acid methyl esters.

    PubMed

    Roux, María Victoria; Temprado, Manuel; Notario, Rafael; Chickos, James S; Santos, Ana Filipa L O M; da Silva, Manuel A V Ribeiro

    2007-06-21

    Thiophene-based compounds have widespread use in modern drug design, biodiagnostics, electronic and optoelectronic devices, and conductive polymers. The present study reports an experimental and computational thermochemical study on the relative stabilities of 2- and 3-thiopheneacetic acid methyl esters. The enthalpies of combustion and vaporization were measured by a rotating-bomb combustion calorimeter, Calvet microcalorimetry, and correlation gas chromatography, and the gas-phase enthalpies of formation at T=298.15 K were determined. Standard ab initio molecular orbital calculations at the G3 level were performed, and a theoretical study of the molecular and electronic structure of the compounds studied was carried out. Calculated enthalpies of formation, using atomization and isodesmic reactions are in very good agreement with the experimental results. PMID:17530748

  1. Decommissioning of Experimental Breeder Reactor - II Complex, Post Sodium Draining

    SciTech Connect

    J. A. Michelbacher; S. Paul Henslee; Collin J. Knight; Steven R. sherman

    2005-09-01

    The Experimental Breeder Reactor - II (EBR-II) was shutdown in September 1994 as mandated by the United States Department of Energy. This sodium-cooled reactor had been in service since 1964. The bulk sodium was drained from the primary and secondary systems and processed. Residual sodium remaining in the systems after draining was converted into sodium bicarbonate using humid carbon dioxide. This technique was tested at Argonne National Laboratory in Illinois under controlled conditions, then demonstrated on a larger scale by treating residual sodium within the EBR-II secondary cooling system, followed by the primary tank. This process, terminated in 2002, was used to place a layer of sodium bicarbonate over all exposed surfaces of sodium. Treatment of the remaining EBR-II sodium is governed by the Resource Conservation and Recovery Act (RCRA). The Idaho Department of Environmental Quality issued a RCRA Operating Permit in 2002, mandating that all hazardous materials be removed from EBR-II within a 10 year period, with the ability to extend the permit and treatment period for another 10 years. A preliminary plan has been formulated to remove the remaining sodium and NaK from the primary and secondary systems using moist carbon dioxide, steam and nitrogen, and a water flush. The moist carbon dioxide treatment was resumed in May 2004. As of August 2005, approximately 60% of the residual sodium within the EBR-II primary tank had been treated. This process will continue through the end of 2005, when it is forecast that the process will become increasingly ineffective. At that time, subsequent treatment processes will be planned and initiated. It should be noted that the processes and anticipated costs associated with these processes are preliminary. Detailed engineering has not been performed, and approval for these methods has not been obtained from the regulator or the sponsors.

  2. The 9-methyl group of retinal is essential for rapid Meta II decay and phototransduction quenching in red cones.

    PubMed

    Estevez, Maureen E; Kolesnikov, Alexander V; Ala-Laurila, Petri; Crouch, Rosalie K; Govardovskii, Victor I; Cornwall, M Carter

    2009-08-01

    Cone photoreceptors of the vertebrate retina terminate their response to light much faster than rod photoreceptors. However, the molecular mechanisms underlying this rapid response termination in cones are poorly understood. The experiments presented here tested two related hypotheses: first, that the rapid decay rate of metarhodopsin (Meta) II in red-sensitive cones depends on interactions between the 9-methyl group of retinal and the opsin part of the pigment molecule, and second, that rapid Meta II decay is critical for rapid recovery from saturation of red-sensitive cones after exposure to bright light. Microspectrophotometric measurements of pigment photolysis, microfluorometric measurements of retinol production, and single-cell electrophysiological recordings of flash responses of salamander cones were performed to test these hypotheses. In all cases, cones were bleached and their visual pigment was regenerated with either 11-cis retinal or with 11-cis 9-demethyl retinal, an analogue of retinal lacking the 9-methyl group. Meta II decay was four to five times slower and subsequent retinol production was three to four times slower in red-sensitive cones lacking the 9-methyl group of retinal. This was accompanied by a significant slowing of the recovery from saturation in cones lacking the 9-methyl group after exposure to bright (>0.1% visual pigment photoactivated) but not dim light. A mathematical model of the turn-off process of phototransduction revealed that the slower recovery of photoresponse can be explained by slower Meta decay of 9-demethyl visual pigment. These results demonstrate that the 9-methyl group of retinal is required for steric chromophore-opsin interactions that favor both the rapid decay of Meta II and the rapid response recovery after exposure to bright light in red-sensitive cones.

  3. PHF8 Targets Histone Methylation and RNA Polymerase II To Activate Transcription▿ †

    PubMed Central

    Fortschegger, Klaus; de Graaf, Petra; Outchkourov, Nikolay S.; van Schaik, Frederik M. A.; Timmers, H. T. Marc; Shiekhattar, Ramin

    2010-01-01

    Mutations in PHF8 are associated with X-linked mental retardation and cleft lip/cleft palate. PHF8 contains a plant homeodomain (PHD) in its N terminus and is a member of a family of JmjC domain-containing proteins. While PHDs can act as methyl lysine recognition motifs, JmjC domains can catalyze lysine demethylation. Here, we show that PHF8 is a histone demethylase that removes repressive histone H3 dimethyl lysine 9 marks. Our biochemical analysis revealed specific association of the PHF8 PHD with histone H3 trimethylated at lysine 4 (H3K4me3). Chromatin immunoprecipitation followed by high-throughput sequencing indicated that PHF8 is enriched at the transcription start sites of many active or poised genes, mirroring the presence of RNA polymerase II (RNAPII) and of H3K4me3-bearing nucleosomes. We show that PHF8 can act as a transcriptional coactivator and that its activation function largely depends on binding of the PHD to H3K4me3. Furthermore, we present evidence for direct interaction of PHF8 with the C-terminal domain of RNAPII. Importantly, a PHF8 disease mutant was defective in demethylation and in coactivation. This is the first demonstration of a chromatin-modifying enzyme that is globally recruited to promoters through its association with H3K4me3 and RNAPII. PMID:20421419

  4. Synthesis, spectroscopic characterization, DNA interaction and biological activities of Mn(II), Co(II), Ni(II) and Cu(II) complexes with [(1H-1,2,4-triazole-3-ylimino)methyl]naphthalene-2-ol

    NASA Astrophysics Data System (ADS)

    Gaber, Mohamed; El-Wakiel, Nadia A.; El-Ghamry, Hoda; Fathalla, Shaimaa K.

    2014-11-01

    Manganese(II), cobalt(II), nickel(II) and copper(II) complexes of [(1H-1,2,4-triazole-3-ylimino)methyl]naphthalene-2-ol have been synthesized. The structure of complexes have been characterized by elemental analysis, molar conductance, magnetic moment measurements and spectral (IR, 1H NMR, EI-mass, UV-Vis and ESR), and thermal studies. The results showed that the chloro and nitrato Cu(II) complexes have octahedral geometry while Ni(II), Co(II) and Mn(II) complexes in addition to acetato Cu(II) complex have tetrahedral geometry. The possible structures of the metal complexes have been computed using the molecular mechanic calculations using the hyper chem. 8.03 molecular modeling program to confirm the proposed structures. The kinetic and thermodynamic parameters of the thermal decomposition steps were calculated from the TG curves. The binding modes of the complexes with DNA have been investigated by UV-Vis absorption titration. The results showed that the mode of binding of the complexes to DNA is intercalative or non-intercalative binding modes. Schiff base and its metal complexes have been screened for their in vitro antimicrobial activities against Gram positive bacteria (Staphylococcus aureus), Gram negative bacteria (Escherichia coli and Pesudomonas aeruginosa), fungi (Asperigllus flavus and Mucer) and yeast (Candida albicans and Malassezia furfur).

  5. Experimental Stark widths and shifts of Ti II spectral lines

    NASA Astrophysics Data System (ADS)

    Manrique, J.; Aguilera, J. A.; Aragón, C.

    2016-10-01

    Stark widths and shifts of Ti II lines with wavelengths in the range 2500-4600 Å have been determined by laser-induced breakdown spectroscopy. The temperature and electron density of the plasma vary in the ranges 11 970-15 520 K and (2.0-7.2) × 1017 cm-3, respectively, for the different measurement instants from 0.6 to 1.8 μs. The samples used are fused glass discs with different titanium concentrations, selected to control the self-absorption of the lines. The Stark widths and shifts are compared with the experimental and theoretical data available in the literature.

  6. Current status of experimental breeder reactor-II [EBR-II] shutdown planning

    SciTech Connect

    McDermott, M. D.; Griffin, C. D.; Michelbacher, J. A.; Earle, O. K.

    2000-05-08

    The Experimental Breeder Reactor--II (EBR-II) at Argonne National Laboratory--West (ANL-W) in Idaho, was shutdown in September, 1994 as mandated by the US Department of Energy. This sodium cooled reactor had been in service since 1964, and was to be placed in an industrially and radiologically safe condition for ultimate decommissioning. The deactivation of a liquid metal reactor presents unique concerns. The first major task associated with the project was the removal of all fueled assemblies. In addition, sodium must be drained from systems and processed for ultimate disposal. Residual quantities of sodium remaining in systems must be deactivated or inerted to preclude future hazards associated with pyrophoricity and generation of potentially explosive hydrogen gas. A Sodium Process Facility was designed and constructed to react the elemental sodium from the EBR-II primary and secondary systems to sodium hydroxide for disposal. This facility has a design capacity to allow the reaction of the complete inventory of sodium at ANL-W in less than two years. Additional quantities of sodium from the Fermi-1 reactor are also being treated at the Sodium Process Facility. The sodium environment and the EBR-II configuration, combined with the radiation and contamination associated with thirty years of reactor operation, posed problems specific to liquid metal reactor deactivation. The methods being developed and implemented at EBR-II can be applied to other similar situations in the US and abroad.

  7. Anti-inflammatory activity of methyl palmitate and ethyl palmitate in different experimental rat models

    SciTech Connect

    Saeed, Noha M.; El-Demerdash, Ebtehal; Abdel-Rahman, Hanaa M.; Algandaby, Mardi M.; Al-Abbasi, Fahad A.; Abdel-Naim, Ashraf B.

    2012-10-01

    Methyl palmitate (MP) and ethyl palmitate (EP) are naturally occurring fatty acid esters reported as inflammatory cell inhibitors. In the current study, the potential anti-inflammatory activity of MP and EP was evaluated in different experimental rat models. Results showed that MP and EP caused reduction of carrageenan-induced rat paw edema in addition to diminishing prostaglandin E2 (PGE2) level in the inflammatory exudates. In lipopolysaccharide (LPS)-induced endotoxemia in rats, MP and EP reduced plasma levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). MP and EP decreased NF-κB expression in liver and lung tissues and ameliorated histopathological changes caused by LPS. Topical application of MP and EP reduced ear edema induced by croton oil in rats. In the same animal model, MP and EP reduced neutrophil infiltration, as indicated by decreased myeloperoxidase (MPO) activity. In conclusion, this study demonstrates the effectiveness of MP and EP in combating inflammation in several experimental models. -- Highlights: ► Efficacy of MP and EP in combating inflammation was displayed in several models. ► MP and EP reduced carrageenan-induced rat paw edema and prostaglandin E2 level. ► MP and EP decreased TNF-α and IL-6 levels in experimental endotoxemia. ► MP and EP reduced NF-κB expression and histological changes in rat liver and lung. ► MP and EP reduced croton oil-induced ear edema and neutrophil infiltration.

  8. Epidemiological and experimental studies on the effects of methyl isocyanate on the course of pregnancy

    SciTech Connect

    Varma, D.R.

    1987-06-01

    Although press reports indicate that the leakage of methyl isocyanate (MIC) on December 3, 1984, in Bhopal has led to an increase in spontaneous abortions, stillbirths, infant mortality, and fetal abnormalities, no clinical or experimental studies on the reproductive toxicity of MIC were reported in scientific journals for several months after the accident. The authors therefore conducted, 9 months after the accident, a preliminary survey of 3270 families in Bhopal and experimental studies on the effects of MIC in pregnant mice. It was found that 43% of pregnancies in women residing near the Union Carbide pesticide plant did not result in the birth of a live child. Likewise, exposure of mice to relatively low concentrations of MIC (9 and 15 ppm) for 3 hr caused complete resorption in more than 75% of animals. A decrease in fetal and placental weights was observed at 2 to 15 ppm MIC. In general, the experimental findings in mice corroborate the epidemiological data from Bhopal. The mechanism of the fetal toxicity of MIC remains to e established.

  9. Crystal structures of copper(II) and nickel(II) nitrate and chloride complexes with 4-bromo-2-[(2-hydroxyethylimino)-methyl]phenol

    SciTech Connect

    Chumakov, Yu. M.; Tsapkov, V. I.; Filippova, I. G.; Bocelli, G.; Gulea, A. P.

    2008-07-15

    The crystal structures of {l_brace}4-bromo-2-[(2-hydroxyethylimino)-methyl]phenolo{r_brace}aquacopper(II) nitrate hemihydrate (I), chloro-{l_brace}4-bromo-2-[(2-hydroxyethylimino)-methyl]phenolo{r_brace}copper hemihydrate (II), and chloro-{l_brace}4-bromo-2-[(2-hydroxyethylimino)-methyl]phenolo{r_brace}aquanickel (III) are determined using X-ray diffraction. Crystals of compound I are formed by cationic complexes, nitrate ions, and solvate water molecules. In the cation, the copper atom coordinates the singly deprotonated molecule of tridentate azomethine and the water molecule. The copper complexes are joined into centrosymmetric dimers by the O{sub w}-H...O hydrogen bonds. The crystal structure of compound II is composed of binuclear copper complexes and solvate water molecules. The copper atom coordinates the O,N,O ligand molecule and the chlorine ion, which fulfills a bridging function. The coordination polyhedron of the metal atom is a distorted tetragonal bipyramid in which the vertex is occupied by the chlorine atom of the neighboring complex in the dimer. Compound III is a centrosymmetric dimer complex. The coordination polyhedra of two nickel atoms related via the inversion center are distorted octahedra shared by the edge.

  10. Crystal structure of bis-(N,N,N',N'-tetra-methyl-guanidinium) tetra-chlorido-cuprate(II).

    PubMed

    Ndiaye, Mamadou; Samb, Abdoulaye; Diop, Libasse; Maris, Thierry

    2016-07-01

    In the structure of the title salt, (C5H14N3)2[CuCl4], the Cu(II) atom in the anion lies on a twofold rotation axis. The tetra-chlorido-cuprate(II) anion adopts a flattened tetra-hedral coordination environment and inter-acts electrostatically with the tetra-methyl-guanidinium cation. The crystal packing is additionally consolidated through N-H⋯Cl and C-H⋯Cl hydrogen bonds, resulting in a three-dimensional network structure. PMID:27555960

  11. Synthesis, characterization, antimicrobial activity and carbonic anhydrase enzyme inhibitor effects of salicilaldehyde-N-methyl p-toluenesulfonylhydrazone and its Palladium(II), Cobalt(II) complexes

    NASA Astrophysics Data System (ADS)

    Alyar, Saliha; Adem, Şevki

    2014-10-01

    We report the synthesis of the ligand, salicilaldehyde-N-methyl p-toluenesulfonylhydrazone (salptsmh) derived from p-toluenesulfonicacid-1-methylhydrazide (ptsmh) and its Pd(II) and Co(II) metal complexes were synthesized for the first time. The structure of the ligand and their complexes were investigated using elemental analysis, magnetic susceptibility, molar conductance and spectral (IR, NMR and LC-MS) measurements. Salptsmh has also been characterized by single crystal X-ray diffraction. 1H and 13C shielding tensors for crystal structure were calculated with GIAO/DFT/B3LYP/6-311++G(d,p) methods in CDCl3. The complexes were found to have general composition [ML2]. The results of elemental analysis showed 1:2 (metal/ligand) stoichiometry for all the complex. Magnetic and spectral data indicate a square planar geometry for Pd(II) complex and a distorted tetrahedral geometry for Co(II) complexes. The ligand and its metal chelates have been screened for their antimicrobial activities using the disk diffusion method against the selected Gram positive bacteria: Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, Enterococcus faecalis, Gram negative bacteria: Eschericha coli, Pseudomonas aeruginosa, Klebsiella pneumonia. The inhibition activities of these compounds on carbonic anhydrase II (CA II) and carbonic anhydrase I (CA I) have been investigated by comparing IC50 and Ki values and it has been found that Pd(II) complex have more enzyme inhibition efficiency than salptsmh and Co(II) complex.

  12. DNA methylation of angiotensin II receptor gene in nonalcoholic steatohepatitis-related liver fibrosis

    PubMed Central

    Asada, Kiyoshi; Aihara, Yosuke; Takaya, Hiroaki; Noguchi, Ryuichi; Namisaki, Tadashi; Moriya, Kei; Uejima, Masakazu; Kitade, Mitsuteru; Mashitani, Tsuyoshi; Takeda, Kosuke; Kawaratani, Hideto; Okura, Yasushi; Kaji, Kosuke; Douhara, Akitoshi; Sawada, Yasuhiko; Nishimura, Norihisa; Seki, Kenichiro; Mitoro, Akira; Yamao, Junichi; Yoshiji, Hitoshi

    2016-01-01

    AIM To clarify whether Agtr1a methylation is involved in the development of nonalcoholic steatohepatitis (NASH)-related liver fibrosis in adult rats. METHODS A choline-deficient amino acid (CDAA) diet model was employed for methylation analysis of NASH-related liver fibrosis. Agtr1a methylation levels were measured in the livers of CDAA- and control choline-sufficient amino acid (CSAA)-fed rats for 8 and 12 wk using quantitative methylation-specific PCR. Hepatic stellate cells (HSCs) were isolated by collagenase digestion of the liver, followed by centrifugation of the crude cell suspension through a density gradient. Agtr1a methylation and its gene expression were also analyzed during the activation of HSCs. RESULTS The mean levels of Agtr1a methylation in the livers of CDAA-fed rats (11.5% and 18.6% at 8 and 12 wk, respectively) tended to be higher (P = 0.06 and 0.09, respectively) than those in the livers of CSAA-fed rats (2.1% and 5.3% at 8 and 12 wk, respectively). Agtr1a was not methylated at all in quiescent HSCs, but was clearly methylated in activated HSCs (13.8%, P < 0.01). Interestingly, although Agtr1a was hypermethylated, the Agtr1a mRNA level increased up to 2.2-fold (P < 0.05) in activated HSCs compared with that in quiescent HSCs, suggesting that Agtr1a methylation did not silence its expression but instead had the potential to upregulate its expression. These findings indicate that Agtr1a methylation and its upregulation of gene expression are associated with the development of NASH-related liver fibrosis. CONCLUSION This is the first study to show that DNA methylation is potentially involved in the regulation of a renin-angiotensin system-related gene expression during liver fibrosis. PMID:27729955

  13. Aerobic oxidation of methyl p-tolyl sulfide catalyzed by a remarkably labile heteroscorpionate RuII-aqua complex, fac-[RuII(H2O)(dpp)(tppm)]2+.

    PubMed

    Huynh, My Hang V; Witham, Laura M; Lasker, Joanne M; Wetzler, Modi; Mort, Brendan; Jameson, Donald L; White, Peter S; Takeuchi, Kenneth J

    2003-01-15

    fac-[RuII(Cl)(dpp)(L3)]+ (L3 = tris(pyrid-2-yl)methoxymethane (tpmm) = [1A]+ and tris(pyrid-2-yl)pentoxymethane (tppm) = [1B]+ and dpp = di(pyrazol-1-yl)propane) rapidly undergo ligand substitution with water to form fac-[RuII(H2O)(dpp)(L3)]2+ (L3 = tpmm = [2A]2+ and tppm = [2B]2+). In the structure of [2A]2+, the distorted octahedral arrangement of ligands around Ru is evident by a long Ru(1)-O(40) of 2.172(3) A and a large angle O(40)-Ru(1)-N(51) of 96.95(14) degrees . The remarkably short distance between O(40) of H2O and H(45a) of dpp confirms the heteroscorpionate ligand effect of dpp on H2O. [2B]2+ aerobically catalyzes methyl p-tolyl sulfide to methyl p-tolyl sulfoxide in 1,2-dichlorobenzene at 25.0 +/- 0.1 degrees C under 11.4 psi of O2. Experimental facts in support of this aerobic sulfide oxidation are the absence of H2O2 and the oxidative reactivity of the putative Ru(IV)-oxo intermediate toward methyl p-tolyl sulfide, 2-propanol, and allyl alcohol. This study provides the first documented example of aerobic-sulfide oxidation catalyzed by the remarkably labile heteroscorpionate Ru(II)-aqua complex without the formation of a highly reactive peroxide as an intermediate.

  14. Shutdown and Closure of the Experimental Breeder Reactor - II

    SciTech Connect

    Michelbacher, John A.; Baily, Carl E.; Baird, Daniel K.; Henslee, S. Paul; Knight, Collin J.; Rosenberg, Kenneth E.

    2002-07-01

    The Department of Energy mandated the termination of the Integral Fast Reactor (IFR) Program, effective October 1, 1994. To comply with this decision, Argonne National Laboratory-West (ANL-W) prepared a plan providing detailed requirements to maintain the Experimental Breeder Reactor - II (EBR-II) in a radiologically and industrially safe condition, including removal of all irradiated fuel assemblies from the reactor plant, and removal and stabilization of the primary and secondary sodium, a liquid metal used to transfer heat within the reactor plant. The EBR-II is a pool-type reactor. The primary system contained approximately 325 m{sup 3} (86,000 gallons) of sodium and the secondary system contained 50 m{sup 3} (13,000 gallons). In order to properly dispose of the sodium in compliance with the Resource Conservation and Recovery Act (RCRA), a facility was built to react the sodium to a solid sodium hydroxide monolith for burial as a low level waste in a land disposal facility. Deactivation of a liquid metal fast breeder reactor (LMFBR) presents unique concerns. Residual amounts of sodium remaining in circuits and components must be passivated, inerted, or removed to preclude future concerns with sodium-air reactions that could generate potentially explosive mixtures of hydrogen and leave corrosive compounds. The passivation process being implemented utilizes a moist carbon dioxide gas that generates a passive layer of sodium carbonate/sodium bicarbonate over any quantities of residual sodium. Tests being conducted will determine the maximum depths of sodium that can be reacted using this method, defining the amount that must be dealt with later to achieve RCRA clean closure. Deactivation of the EBR-II complex is on schedule for a March, 2002, completion. Each system associated with EBR-II has an associated lay-up plan defining the system end state, as well as instructions for achieving the lay-up condition. A goal of system-by-system lay-up is to minimize

  15. Shutdown and closure of the experimental breeder reactor - II.

    SciTech Connect

    Michelbacher, J. A.; Baily, C. E.; Baird, D. K.; Henslee, S. P.; Knight, C. J.; Rosenberg, K. E.

    2002-09-26

    The Department of Energy mandated the termination of the Integral Fast Reactor (IFR) Program, effective October 1, 1994. To comply with this decision, Argonne National Laboratory-West (ANL-W) prepared a plan providing detailed requirements to maintain the Experimental Breeder Reactor-II (EBR-II) in a radiologically and industrially safe condition, including removal of all irradiated fuel assemblies from the reactor plant, and removal and stabilization of the primary and secondary sodium, a liquid metal used to transfer heat within the reactor plant. The EBR-II is a pool-type reactor. The primary system contained approximately 325 m{sup 3} (86,000 gallons) of sodium and the secondary system contained 50 m{sub 3} (13,000 gallons). In order to properly dispose of the sodium in compliance with the Resource Conservation and Recovery Act (RCRA), a facility was built to react the sodium to a solid sodium hydroxide monolith for burial as a low level waste in a land disposal facility. Deactivation of a liquid metal fast breeder reactor (LMFBR) presents unique concerns. Residual amounts of sodium remaining in circuits and components must be passivated, inerted, or removed to preclude future concerns with sodium-air reactions that could generate potentially explosive mixtures of hydrogen and leave corrosive compounds. The passivation process being implemented utilizes a moist carbon dioxide gas that generates a passive layer of sodium carbonate/sodium bicarbonate over any quantities of residual sodium. Tests being conducted will determine the maximum depths of sodium that can be reacted using this method, defining the amount that must be dealt with later to achieve RCRA clean closure. Deactivation of the EBR-II complex is on schedule for a March, 2002, completion. Each system associated with EBR-II has an associated layup plan defining the system end state, as well as instructions for achieving the layup condition. A goal of system-by-system layup is to minimize surveillance

  16. Experimental Electronic Spectroscopy of Two PAHs: Naphthalene and 2-METHYL Naphthalene

    NASA Astrophysics Data System (ADS)

    Friha, H.; Feraud, G.; Pino, T.; Brechignac, Ph.; Parneix, P.; Dhaoudi, Z.; Jaidane, N.; Galila, H.; Troy, T.; Schmidt, T.

    2011-06-01

    The presence of polycyclic aromatic hydrocarbons (PAHs) in the interstellar medium (ISM) was suggested in the mid-80's. Since then, their important role in the physico-chemical evolution of the ISM has been confirmed. Interstellar PAHs have been in particular proposed as possible carriers of some Diffuse Interstellar Bands (DIBs). These absorption bands are seen in the spectra of reddened stars from the visible to the near infrared and constitute a major astrophysical issue. Our purpose is to obtain electronic spectra of gas phase PAHs which will be used to probe their participation to the interstellar extinction curve from the visible (DIBs) to the UV (bump). For this goal PAHs cations represent an excellent set of target species. A new way of forming PAH+-Ar_n clusters cations has been implemented in the experimental set-up 'ICARE' at ISMO (Orsay) giving us the capability to measure the electronic spectra of cold PAH cations in the gas phase through the "Ar tagging" trick. Two molecules have been investigated in this way: naphthalene (C_1_0H_8) and 2- methyl naphthalene (C_1_1H_1_0). Clusters of naphthalene and (or 2-methyl-naphthalene) with Ar atoms are first formed in a supersonic jet, before being hit by a 281 nm laser beam which photo-ionizes the clusters which are then injected in a molecular beam through a skimmer. A tunable laser beam crossing downstream photo-dissociates the cations. The bare PAH fragments are detected using a Time-Of-Flight spectrometer while scanning the visible laser wavelength from 470 to 690 nm.

  17. Crystal structure of bis-(2-{[(pyridin-2-yl)methyl-idene]amino}-benzoato-κ(3) N,N',O)cobalt(II) N,N-di-methyl-formamide sesquisolvate.

    PubMed

    Buvaylo, Elena A; Kokozay, Vladimir N; Vassilyeva, Olga Yu; Skelton, Brian W

    2014-10-01

    The title compound, [Co(C13H9N2O2)2]·1.5C3H7NO, is formed as a neutral Co(II) complex with di-methyl-formamide (DMF) solvent mol-ecules. The Co(II) atom has a distorted O2N4 octa-hedral coordination sphere defined by two tridentate anionic Schiff base ligands with the O atoms being cis. The coordination sphere around the Co(II) atom is geometrically different from that reported for the co-crystal [Co(C13H9N2O2)2]·AA·H2O (AA is anthranilic acid). One of the DMF solvent mol-ecules was modelled as being disordered about a crystallographic inversion centre with half-occupancy. The crystal structure is made up from alternating layers of complex mol-ecules and DMF mol-ecules parallel to (010). C-H⋯O hydrogen-bonding inter-actions between the complex mol-ecules and the solvent mol-ecules consolidate the crystal packing. PMID:25484642

  18. Pdx-1 links histone H3-Lys-4 methylation to RNA polymerase II elongation during activation of insulin transcription.

    PubMed

    Francis, Joshua; Chakrabarti, Swarup K; Garmey, James C; Mirmira, Raghavendra G

    2005-10-28

    Expression of the insulin gene is nearly exclusive to the beta cells of the pancreatic islets. Although the sequence-specific transcription factors that regulate insulin expression have been well studied, the interrelationship between these factors, chromatin structure, and transcriptional elongation by RNA polymerase II (pol II) has remained undefined. In this regard, recent studies have begun to establish a role for the methylation of histone H3 in the initiation or elongation of transcription by pol II. To determine a role for the transcriptional activator Pdx-1 in the maintenance of chromatin structure and pol II recruitment at the insulin gene, we performed small interfering RNA-mediated knockdown of Pdx-1 in betaTC3 cells and subsequently studied histone modifications and pol II recruitment by chromatin immunoprecipitation. We demonstrated here that the 50% fall in insulin transcription following knockdown of Pdx-1 is accompanied by a 60% fall in dimethylated histone H3-Lys-4 at the insulin promoter. H3-Lys-4 methylation at the insulin promoter may be mediated, at least partially, by the methyltransferase Set9. Immunohistochemical analysis revealed that Set9 is expressed in an islet-enriched pattern in the pancreas, similar to the pattern of Pdx-1 expression. The recruitment of Set9 to the insulin gene appears to be a consequence of its direct interaction with Pdx-1, and small interfering RNA-mediated knockdown of Set9 attenuates insulin transcription. Pdx-1 knockdown was also associated with an overall shift in the recruitment of pol II isoforms to the insulin gene, from an elongation isoform (Ser(P)-2) to an initiation isoform (Ser(P)-5). Our findings therefore suggest a model whereby Pdx-1 plays a novel role in linking H3-Lys-4 dimethylation and pol II elongation to insulin transcription.

  19. Arm-free paraplegic standing--Part II: Experimental results.

    PubMed

    Matjacić, Z; Bajd, T

    1998-06-01

    In Part I, we proposed an approach for restoring unsupported standing to thoracic-level paraplegics. The theoretical analysis and simulation of an underactuated double inverted pendulum, representing the standing subject, showed that arm-free standing might be achieved. Here in Part II, we present the mechanical apparatus which we used in our experiments and experimental results from tests of the balance-control strategy. We demonstrate that an intact and a paraplegic subject could perform quiet standing with the ankle stiffness set to 8 Nm/degree or even less (the intact subject). Both were also able to recover from disturbances, imposed by the artificial ankle joint of the apparatus. Introducing cognitive auditory feedback greatly improved the standing abilities of both subjects. PMID:9631321

  20. Canopy Level Emissions of 2-methyl-3-buten-2-ol, monoterpenes, and sesquiterpenes from a Pinus taeda Experimental Plantation

    EPA Science Inventory

    Emissions of biogenic volatile organic compounds (BVOC) observed during 2007 from a Pinus taeda experimental plantation in Central North Carolina are compared with model estimates from MEGAN 2.1. Relaxed Eddy Accumulation (REA) estimates of 2-methyl-3-buten-2-ol (MBO) fluxes are ...

  1. Changes in DNA methylation fingerprint of Quercus ilex trees in response to experimental field drought simulating projected climate change.

    PubMed

    Rico, L; Ogaya, R; Barbeta, A; Peñuelas, J

    2014-03-01

    Rapid genetic changes in plants have been reported in response to current climate change. We assessed the capacity of trees in a natural forest to produce rapid acclimation responses based on epigenetic modifications. We analysed natural populations of Quercus ilex, the dominant tree species of Mediterranean forests, using the methylation-sensitive amplified polymorphism (MSAP) technique to assess patterns and levels of methylation in individuals from unstressed forest plots and from plots experimentally exposed to drought for 12 years at levels projected for the coming decades. The percentage of hypermethylated loci increased, and the percentage of fully methylated loci clearly decreased in plants exposed to drought. Multivariate analyses exploring the status of methylation at MSAP loci also showed clear differentiation depending on stress. The PCA scores for the MSAP profiles clearly separated the genetic from the epigenetic structure, and also significantly separated the samples within each group in response to drought. Changes in DNA methylation highlight the large capacity of plants to rapidly acclimate to changing environmental conditions, including trees with long life spans, and our results demonstrate those changes. These changes, although unable to prevent the decreased growth and higher mortality associated with this experimental drought, occurred together with a dampening in such decreases as the long-term treatment progressed.

  2. The dynamics of 57Fe nuclei in Fe(II)-DNA and [Fe(II)(1-methyl-2-mercaptoimidazole)2]-DNA condensates.

    PubMed

    Silvestri, Arturo; Ruisi, Giuseppe; Girasolo, Maria Assunta

    2002-11-25

    Alcoholic solutions of FeCl(2) and Fe(II)(Hmmi)(2)Cl(2) (Hmmi=1-methyl-2-mercaptoimidazole) induce calf thymus DNA condensation from aqueous solutions buffered at pH 7.4. A 1:1 Fe(II)-(DNA monomer) stoichiometry is assumed. The (57)Fe Mössbauer hyperfine parameters suggest an octahedral coordination environment, severely distorted, in both Fe(II)-(DNA monomer) and [Fe(II)(Hmmi)(2)]-(DNA monomer) condensates. The dynamic properties of iron nuclei in freeze-dried samples were investigated by means of variable temperature (57)Fe Mössbauer spectroscopy. Mean square displacements, (T), were calculated, such as the effective vibrating mass and the Mössbauer lattice temperature of the solids. increases linearly with the temperature in the whole temperature range explored; the absolute values are typical for lattice or solid-state vibrations. Very similar values for the effective vibrating masses were extracted, suggesting comparable covalency of the bonding interaction between the metal atom and its ligands, while the Mössbauer lattice temperatures show a softening of the lattice for [Fe(II)(Hmmi)(2)]-(DNA monomer) with respect to Fe(II)-(DNA monomer) condensate.

  3. Gas Phase Elimination Kinetics of Methyl Mandelate: Experimental and DFT Studies

    NASA Astrophysics Data System (ADS)

    Rotinov, Alexandra; Escalante, Luz; Ramirez, Beatriz; Pereira, Desiree; Córdova, Tania; Chuchani, Gabriel

    2009-10-01

    The gas phase elimination kinetics of racemic methyl mandelate was determined in a static system, and yielded on decomposition benzaldehyde, methanol, and carbon monoxide. The reaction was homogeneous, unimolecular, and follows a first-order law in the temperature range 379.5-440 °C and pressure range of 21.5-71.1 Torr. The variation of the rate coefficient with temperature is expressed by the following Arrhenius equation: log k1 = (12.70 ± 0.14) - (206.5 ± 1.9) kJ/mol (2.303RT)-1. The theoretical estimations of the kinetics and thermodynamics parameters were carried out using DFT methods B3LYP, B3PW91, MPW1PW91, and PBEPBE. Calculation results are in reasonably good agreement with the experimental energy and enthalpy values when using the PBEPBE DFT functional. However, regarding the entropy of activation, the MPW1PW91 functional is more adequate to describe the reaction. These calculations imply a molecular concerted nonsynchronous mechanism involving a two-step process, where the formation of the unstable α-lactone intermediate is the rate-determining factor. The lactone intermediate rapidly decarbonylates to produce benzaldehyde and carbon monoxide. The transition state is late in the reaction coordinate, resembling the lactone configuration.

  4. Synthesis and characterization of Pd(II)-methyl complexes with N-heterocyclic carbene-amine ligands.

    PubMed

    Warsink, Stefan; de Boer, Sandra Y; Jongens, Lianne M; Fu, Ching-Feng; Liu, Shiuh-Tzung; Chen, Jwu-Ting; Lutz, Martin; Spek, Anthony L; Elsevier, Cornelis J

    2009-09-21

    A number of palladium(ii) complexes with a heteroditopic NHC-amine ligand and their precursor silver(i) carbene complexes have been efficiently prepared and their structural features have been investigated. The heteroditopic coordination of this ligand class was unequivocally shown by NMR-spectroscopy and X-ray crystallographic analysis. The neutral and cationic cis-methyl-palladium(NHC) complexes are not prone to reductive elimination, which is normally a major degenerative pathway for this type of complex. In contrast, under carbon monoxide atmosphere rapid reductive elimination of the acyl-imidazolium salt was observed.

  5. Electronic and optical response of functionalized Ru(II) complexes: joint theoretical and experimental study

    SciTech Connect

    Kilina, Svetlana; Tretiak, Sergei; Sykora, Milan; Albert, Victor; Badaeva, Ekaterina; Koposov, Alexey

    2008-01-01

    New photovoltaic and photocatalysis applications have been recently proposed based on the hybrid Ru(II)-bipyridine-complex/semiconductor quantum dot systems. In order to attach the Ru(II) complex to the surface of a semiconductor, a linking bridge -- a carboxyl group -- needs to be added to one or two of the 2,2'-bipyridine (bpy) ligands. Such changes in the ligand structure affect electronic and optical properties and, consequently, the charge transfer reactivity of Ru(II)-systems. In this study, we analyze the effects brought by functionalization of bipyridine ligands with the methyl, carboxyl, and carboxilate groups on the electronic structure and optical response of the [Ru(bpy){sub 3}]{sup 2+} complex. First principle calculations based on density functional theory (DFT) and time dependent DFT (TDDFT) are used to simulate the ground and excited-state properties, respectively, of functionalized Ru-complexes in the gas phase and acetonitrile solution. In addition, an effective Frenkel exciton model is used to explain the optical activity and splitting patterns of the low-energy excited states in all molecules. All theoretical results nicely complement and allow for detailed interpretation of experimental absorption spectra of Ru-complexes that have been done in parallel with our theoretical investigations. We found that the carboxyl group breaks the degeneracy of two low-energy optically bright excited states and red-shifts the absorption spectrum, while leaves ionization and affinity energies of complexes almost unchanged. Experimental studies show that deprotonation of the carboxyl group in the Ru-complexes results in a slight blue shift and decrease of oscillator strengths of the low energy absorption peaks. Comparison of experimental and theoretical linear response spectra of deprotonated complexes demonstrate strong agreement if the theoretical calculations are performed with the addition of a dielectric continuum model. A polar solvent is found to play an

  6. Experimental Tests of the Hvbk Equations for he II

    NASA Astrophysics Data System (ADS)

    Snyder, H. A.

    2008-03-01

    We generally accept the HVBK equations as those governing the motion of He II. The simplest test that involves all terms significantly is the prediction of the onset of instability for rotating Couette flow. The calculations show that the critical Reynolds number and the wave number rapidly approach zero as the temperature decreases below the lambda point. The wavelength is longer than most apparatus below T = 2.07 K. All the experimental data, by six different groups, show breaks in the slope of the attenuation of second sound vs. rotation at all temperatures investigated. A large amount of data is available above the break points but the theory to analyze this information is lacking. We present an analysis of standing waves of second sound in an annular cavity when the stationary flow is the Couette regime. We show how the flow due to Taylor cells affects standing waves. Most of the nonrotating normal modes of the cavity are degenerate. The Couette flow couples all the normal modes to the excited mode and splits the degenerate modes. The attenuation is due to the mutual friction force. Errors arise in analyzing the data if we neglect the energy flow to coupled modes.

  7. Methyl bromide emissions from a covered field: I. Experimental conditions and degradation in soil

    SciTech Connect

    Yates, S.R.; Gan, J.; Ernst, F.F.

    1996-01-01

    An experiment is described to investigate the environmental fate and transport of methyl bromide in agricultural systems. The experiment was designed to determine the dynamics of methyl bromide movement through soil, degradation, and total emissions to the atmosphere. This is of particular interest because it will allow an assessment of the environmental impacts (i.e., stratospheric ozone depletion) resulting from the agricultural use of methyl bromide. Methyl bromide was applied at a rate of 843 kg in a 3.5-ha (i.e., 240 kg/ha) field at a depth of 0.25 m and covered with a sheet of 1-mil polyethylene plastic. The maximum methyl bromide concentration in the atmosphere occurred at night between 0200 and 0600 h. During the first 3 d of the experiment, the maximum daily concentrations at 0.2 m above the soil surface were 30, 5, and 1 mg/(m{sup 3} of air), respectively. The trend of reduced emissions with time continued until the plastic was removed, when a momentary increase in the methyl bromide emissions occurred. The maximum soil gas concentration 24 h after injection was 30 g/m{sup 3} located at a 0.25-m depth. When the plastic was removed from the field (at 5.6 d), the maximum soil gas concentration was approximately 2 g/m{sup 3} at a 0.5-m depth. A mass-difference method for estimating the total methyl bromide emissions from the soil, based on degradation of methyl bromide to Br{sup -}, indicates that approximately 39% or 325 kg ({+-} 164 kg) of the applied methyl bromide was converted to Br{sup -} and, therefore, 61% or 518 kg ({+-} 164 kg) was lost via volatilization. 16 refs., 11 figs., 2 tabs.

  8. [Study on S-benzyl-N-(ferrocenyl-1-methyl-metylidene)-dithiocarbazate nickel (II)/cobalt (II) complexes by in-situ FTIR spectroelectrochemistry].

    PubMed

    Wang, Xia-yan; Jin, Bao-kang; Tian, Yu-peng; Lin, Xiang-qin

    2003-02-01

    Comparative studies were carried out by using electrochemistry and in-situ FTIR spectroelectrochemistry for nonlinear optical complexes, S-benzyl-N-(ferrocenyl-1-methyl-metylidene)-dithiocarbazate nickel (II)/cobalt (II) complexes (Ni(LSB)2/Co (LSB)2). The results indicated that Ni(LSB)2 involves two consecutive reversible one-electron oxidation steps, while Co(LSB)2 involves only one two-electron oxidation step. Ni(LSB)2 complex that has a square planar configuration exhibits a moderately strong electronic communication between the two-ferrocene moieties, taking place through the skeleton chain of the ligand due to the extensive electron delocalization in the whole molecule and leads to the appearance of a strong nu c-c vibration band at 1,453 cm-1 during the oxidation process, while Co(LSB)2 complex that has a tetrahedral configuration shows low electron delocalization and has two almost identical ferrocene moieties.

  9. catena-Poly[[bis-(4-methyl-benzene-thiol-ato)cadium(II)]-μ-1,3-di-4-pyridylpropane].

    PubMed

    Zhang, Yan; Zhou, Yan; Han, Lei

    2009-03-28

    In the title compound, [Cd(C(7)H(7)S)(2)(C(13)H(14)N(2))](n), the unique Cd(II) ion, located on a twofold rotation axis, is coordinated by two S atoms and two N atoms in a slightly distorted tetra-hedral environment. Symmetry-related Cd(II) ions are linked via bridging 1,3-di-4-pyridylpropane ligands, forming a zig-zag chain-structure parallel to [001]. In the crystal structure, there are weak intra-chain π-π stacking inter-actions between benzene rings, with a centroid-centroid distance of 3.825 (7) Å, and pairs of chains are inter-digitated with respect to the 4-methyl-benzene-thiol-ate groups.

  10. Experimental and Kinetic Modeling Study of 2-Methyl-2-Butene: Allylic Hydrocarbon Kinetics.

    PubMed

    Westbrook, Charles K; Pitz, William J; Mehl, Marco; Glaude, Pierre-Alexandre; Herbinet, Olivier; Bax, Sarah; Battin-Leclerc, Frederique; Mathieu, Olivier; Petersen, Eric L; Bugler, John; Curran, Henry J

    2015-07-16

    Two experimental studies have been carried out on the oxidation of 2-methyl-2-butene, one measuring ignition delay times behind reflected shock waves in a stainless steel shock tube, and the other measuring fuel, intermediate, and product species mole fractions in a jet-stirred reactor (JSR). The shock tube ignition experiments were carried out at three different pressures, approximately 1.7, 11.2, and 31 atm, and at each pressure, fuel-lean (ϕ = 0.5), stoichiometric (ϕ = 1.0), and fuel-rich (ϕ = 2.0) mixtures were examined, with each fuel/oxygen mixture diluted in 99% Ar, for initial postshock temperatures between 1330 and 1730 K. The JSR experiments were performed at nearly atmospheric pressure (800 Torr), with stoichiometric fuel/oxygen mixtures with 0.01 mole fraction of 2M2B fuel, a residence time in the reactor of 1.5 s, and mole fractions of 36 different chemical species were measured over a temperature range from 600 to 1150 K. These JSR experiments represent the first such study reporting detailed species measurements for an unsaturated, branched hydrocarbon fuel larger than iso-butene. A detailed chemical kinetic reaction mechanism was developed to study the important reaction pathways in these experiments, with particular attention on the role played by allylic C-H bonds and allylic pentenyl radicals. The results show that, at high temperatures, this olefinic fuel reacts rapidly, similar to related alkane fuels, but the pronounced thermal stability of the allylic pentenyl species inhibits low temperature reactivity, so 2M2B does not produce "cool flames" or negative temperature coefficient behavior. The connections between olefin hydrocarbon fuels, resulting allylic fuel radicals, the resulting lack of low-temperature reactivity, and the gasoline engine concept of octane sensitivity are discussed. PMID:25822578

  11. Synthesis, spectral characterization and antioxidant activity studies of a bidentate Schiff base, 5-methyl thiophene-2-carboxaldehyde-carbohydrazone and its Cd(II), Cu(II), Ni(II) and Zn(II) complexes

    NASA Astrophysics Data System (ADS)

    Harinath, Y.; Harikishore Kumar Reddy, D.; Naresh Kumar, B.; Apparao, Ch.; Seshaiah, K.

    2013-01-01

    A new Schiff base bidentate ligand (L), 5-methyl thiophene-2-carboxaldehyde-carbohydrazone and its metal (Cu(II), Cd(II), Ni(II) and Zn(II)) complexes with general stoichiometry [M(L)2X2] (where X = Cl) were synthesized. The ligand and its metal complexes were characterized by elemental analyses, IR, 1H NMR, ESR spectral analyses, and molar conductance studies. The molar conductance data revealed that all the metal chelates are non-electrolytes. IR spectra showed that ligand (L) is coordinated to the metal ions in a bidentate manner with N and O donor sites of the azomethine-N, and carbonyl-O. ESR and UV-Vis spectral data showed that the geometrical structure of the complexes are Orthorhombic. Furthermore, the antioxidant activity of the ligand and its complexes was determined by hydroxyl radical scavenging, DPPH, NO, reducing power methods in vitro. The obtained IC50 value of the DPPH activity for the copper complex (IC50 = 66.4 μm) was higher than other compounds. Microbial assay of the above complexes against Staphylococcus aureus, Escherichia coli, Rhizocotonia bataticola and Alternaria alternata showed that copper complex exhibited higher activity than the other complexes.

  12. Mercury(II) and methyl mercury determinations in water and fish samples by using solid phase extraction and cold vapour atomic absorption spectrometry combination.

    PubMed

    Tuzen, Mustafa; Karaman, Isa; Citak, Demirhan; Soylak, Mustafa

    2009-07-01

    A method has been developed for mercury(II) and methyl mercury speciation on Staphylococcus aureus loaded Dowex Optipore V-493 micro-column in the presented work, by using cold vapour atomic absorption spectrometry. Selective and sequential elution with 0.1 molL(-1) HCl for methyl mercury and 2 molL(-1) HCl for mercury(II) were performed at the pH range of 2-6. Optimal analytical conditions including pH, amounts of biosorbent, sample volumes were investigated. The detection limits of the analytes were 2.5 ngL(-1) for Hg(II) and 1.7 ngL(-1) for methyl mercury. The capacity of biosorbent for mercury(II) and methyl mercury was 6.5 and 5.4 mgg(-1), respectively. The validation of the presented procedure is performed by the analysis of standard reference material. The speciation procedure established was successfully applied to the speciation of mercury(II) and methyl mercury in natural water and microwave digested fish samples.

  13. The thiostrepton A tryptophan methyltransferase TsrM catalyses a cob(II)alamin-dependent methyl transfer reaction

    PubMed Central

    Benjdia, Alhosna; Pierre, Stéphane; Gherasim, Carmen; Guillot, Alain; Carmona, Manon; Amara, Patricia; Banerjee, Ruma; Berteau, Olivier

    2015-01-01

    Ribosomally synthesized and post-translationally modified peptides (RiPPs) are a novel class of natural products including several antibiotics and bacterial toxins. In countless RiPP biosynthetic pathways, cobalamin-dependent radical SAM (B12/rSAM) enzymes play a pivotal role. In the biosynthetic pathway of the antibiotic and anti-cancer agent thiostrepton A, TsrM, a B12/rSAM enzyme, catalyses the transfer of a methyl group to an electrophilic carbon atom of tryptophan. Here we show that methylcob(III)alamin is the probable physiological enzyme cofactor, and cob(II)alamin rather than cob(I)alamin is a key reaction intermediate. Furthermore, we establish that TsrM and a triple-alanine mutant alkylate cob(II)alamin efficiently leading to the synthesis of MeCbl. Exploiting TsrM substrate ambiguity, we demonstrate that TsrM does not catalyse substrate H-atom abstraction like most radical SAM enzymes. Based on these data, we propose an unprecedented radical-based C-methylation mechanism, which further expands the chemical versatility of rSAM enzymes. PMID:26456915

  14. Synthesis, spectroscopic, anticancer, antibacterial and antifungal studies of Ni(II) and Cu(II) complexes with hydrazine carboxamide, 2-[3-methyl-2-thienyl methylene

    NASA Astrophysics Data System (ADS)

    Chandra, Sulekh; Vandana; Kumar, Suresh

    2015-01-01

    Schiff's base ligand(L) hydrazine carboxamide, 2-[3-methyl-2-thienyl methylene] and its metal complexes have been synthesized and characterized by elemental analysis, molar conductance, various spectroscopic techniques such as electronic, IR, 1H NMR, mass, EPR. Molar conductance of complexes in DMF solution corresponds to non-electrolyte. Complexes have general composition [M(L)2X2], where M = Ni(II) and Cu(II), X = Cl-, NO3-, CH3COO- and ½SO42-. On the basis of above spectral studies, an octahedral geometry has been assigned for Ni(II) complexes and tetragonal geometry for Cu(II) complexes except [Cu(L)2SO4] which possesses five coordinated trigonal bipyramidal geometry. These metal complexes were also tested for their anticancer, antibacterial and antifungal activities to assess their inhibition potential. Anticancer activity of ligand and its metal complexes were evaluated using SRB fluorometric assay and Adriamycin (ADR) was applied as positive control. Schiff's base ligand and its metal complexes were screened for their antibacterial and antifungal activity against Escherichia coli, Bacillus cereus and Aspergillus niger, Aspergillus flavus, respectively. Kirby-Bauer single disk susceptibility test was used for antibacterial activity and well diffusion method for antifungal activity of the compounds on the used fungi.

  15. Multiple N-methylation of MT-II backbone amide bonds leads to melanocortin receptor subtype hMC1R selectivity; pharmacological and conformational studies

    PubMed Central

    Doedens, Lucas; Opperer, Florian; Cai, Minying; Beck, Johannes G.; Dedek, Matt; Palmer, Erin; Hruby, Victor J.; Kessler, Horst

    2010-01-01

    Multiple N-methylation is a novel technology to improve bioavailability of peptides and increase receptor subtype selectivity. This technique has been applied here to the superpotent but non-selective cyclic peptide MT-II. A library of all possible 31 backbone N-methylated derivatives has been synthesized and tested for binding and activation at melanocortin receptor subtypes 1, 3, 4 and 5. It turned out that selectivity is improved with every introduced N-methyl group, resulting in several N-methylated selective and potent agonists for the hMC1R. The most potent of these derivatives is N-methylated on four out of five amide bonds in the cyclic structure. Its solution structure indicates a strongly preferred backbone conformation which resembles other a-MSH analogs but possesses much less flexibility and in addition distinct differences in the spatial arrangement of individual amino acid side chains. PMID:20496895

  16. Corrigendum to "Synthesis, structural features, and methyl methacrylate polymerisation of binuclear zinc(II) complexes with tetradentate pyrazolyl ligands" [J. Mol. Struct. 1063 (2014) 70-76

    NASA Astrophysics Data System (ADS)

    Kim, Sunghoon; Kim, Dongil; Lee, Ha-Jin; Lee, Hyosun

    2015-05-01

    The authors regret to inform that 4,4‧-bis-(N,N-di(1H-pyrazolyl-1-methyl)phenyl)methane (L2) and its binuclear 4,4‧-bis-(N,N-di-(1H-pyrazolyl-1-methyl)phenyl)methane(dichloro)Zn(II) complex, namely, [L2Zn2Cl4] in the paper were published as the thesis for the degree of master in the Department of Chemistry at Kyungpook National University in 2003.

  17. Crystal structure of tri-aqua-(2,6-di-methyl-pyrazine-κN (4))bis-(thio-cyanato-κN)manganese(II) 2,5-di-methyl-pyrazine disolvate.

    PubMed

    Suckert, Stefan; Wöhlert, Susanne; Jess, Inke; Näther, Christian

    2015-12-01

    In the crystal structure of the title complex, [Mn(NCS)2(C6H8N2)(H2O)3]·2C6H8N2, the Mn(II) cation is coordinated by two terminally N-bonded thio-cyanate anions, three water mol-ecules and one 2,6-di-methyl-pyrazine ligand within a slightly distorted N3O3 octa-hedral geometry; the entire complex mol-ecule is generated by the application of a twofold rotation axis. The asymmetric unit also contains an uncoordinating 2,5-di-methyl-pyrazine ligand in a general position. Obviously, the coordination to the 2,6-di-methyl-pyrazine ligand is preferred because coordination to the 2,5-di-methyl-pyrazine is hindered due to the bulky methyl group proximate to the N atom. The discrete complexes are linked by water-O-H⋯N(2,6-di-methyl-pyzazine/2,5-di-methyl-pyza-zine) hydrogen bonding, forming a three-dimensional network. In the crystal, mol-ecules are arranged in a way that cavities are formed in which unspecified, disordered solvent molecules reside. These were modelled employing the SQUEEZE routine in PLATON [Spek (2015 ▸). Acta Cryst. C71, 9-18]. The composition of the unit cell does not take into account the presence of the unspecified solvent.

  18. Crystal structure of tri-aqua-(2,6-di-methyl-pyrazine-κN (4))bis-(thio-cyanato-κN)manganese(II) 2,5-di-methyl-pyrazine disolvate.

    PubMed

    Suckert, Stefan; Wöhlert, Susanne; Jess, Inke; Näther, Christian

    2015-12-01

    In the crystal structure of the title complex, [Mn(NCS)2(C6H8N2)(H2O)3]·2C6H8N2, the Mn(II) cation is coordinated by two terminally N-bonded thio-cyanate anions, three water mol-ecules and one 2,6-di-methyl-pyrazine ligand within a slightly distorted N3O3 octa-hedral geometry; the entire complex mol-ecule is generated by the application of a twofold rotation axis. The asymmetric unit also contains an uncoordinating 2,5-di-methyl-pyrazine ligand in a general position. Obviously, the coordination to the 2,6-di-methyl-pyrazine ligand is preferred because coordination to the 2,5-di-methyl-pyrazine is hindered due to the bulky methyl group proximate to the N atom. The discrete complexes are linked by water-O-H⋯N(2,6-di-methyl-pyzazine/2,5-di-methyl-pyza-zine) hydrogen bonding, forming a three-dimensional network. In the crystal, mol-ecules are arranged in a way that cavities are formed in which unspecified, disordered solvent molecules reside. These were modelled employing the SQUEEZE routine in PLATON [Spek (2015 ▸). Acta Cryst. C71, 9-18]. The composition of the unit cell does not take into account the presence of the unspecified solvent. PMID:26870435

  19. Experimental investigations of He II flows at high Reynolds number

    NASA Technical Reports Server (NTRS)

    Van Sciver, Steve W.

    1991-01-01

    Fluid dynamics studies of He II at high Reynolds number (Re(d) greater than 10 exp 6) reveal characteristics which are best interpreted in terms of classical scaling relationships. In particular, the smooth tube friction factor is seen to correlate with the Von Karman-Nikuradse formulation. Also, the performance of a centrifugal pump is unchanged whether being used with He I or He II. These effects are expected to result provided the He II possesses a viscous sublayer and that the drag is determined by laminar flow within this layer. On the other hand, heat transfer in He II is substantially different from that of He I because of the unique internal convection mechanism present in this quantum fluid. These experiments are performed in the University of Wisconsin liquid helium flow facility which has unique capabilities of He II temperature, pressure and flow.

  20. CALCULATED MOLECULAR STRUCTURES AND POTENTIAL ENERGY FUNCTIONS OF PAHS WITH METHYL CROWDING IN THE BAY REGION AND THEIR METABOLITES: COMPARISON TO EXPERIMENTAL STRUCTURES

    EPA Science Inventory

    Abstract Title: Calculated molecular structures and potential energy functions of P AHs with methyl crowding in the bay region and their metabolites: Comparison to experimental structures.

    Abstract:
    PAHs with methyl group substitution near a bay region represent a cl...

  1. CALCULATED MOLECULAR STRUCTURES AND POTENTIAL ENERGY FUNCTIONS OF PAHS WITH METHYL CROWDING IN THE BAY REGION AND THEIR METABOLITES: COMPARISON TO EXPERIMENTAL STRUCTURES

    EPA Science Inventory

    Calculated molecular structures and potential energy functions ofP AHs with methyl crowding in the bay region and their metabolites: Comparison to experimental structures

    PAHs with methyl group substitution near a bay region represent a class of chemicals associated with ...

  2. Experimental and Computational Study on the Molecular Energetics of 2-Pyrrolecarboxylic Acid and 1-Methyl-2-pyrrolecarboxylic Acid

    NASA Astrophysics Data System (ADS)

    Santos, Ana Filipa L. O. M.; Silva, Manuel A. V. Ribeiro Da

    2009-08-01

    This paper reports a combined thermochemical experimental and computational study of 2-pyrrolecarboxylic acid and 1-methyl-2-pyrrolecarboxylic acid. Static bomb combustion calorimetry and Knudsen mass-loss effusion technique were used to determine the standard (p° = 0.1 MPa) molar enthalpies of combustion, ΔcHm°, and sublimation, ΔcrgHm°, respectively, from which the standard (p° = 0.1 MPa) molar enthalpies of formation, in the gaseous phase, at T = 298.15 K, were derived. The values obtained were -(286.3 ± 1.7) and -(291.6 ± 1.7) kJ·mol for 2-pyrrolecarboxylic acid and 1-methyl-2-pyrrolecarboxylic acid, respectively. For comparison purposes, the gas-phase enthalpies of formation of these two compounds were estimated by G3(MP2)//B3LYP and MP2 approaches, using a set of gas-phase working reactions; the results are in excellent agreement with experimental data. G3(MP2)//B3LYP computations were also extended to the calculation of N-H bond dissociation enthalpies, gas-phase acidities and basicities, proton and electron affinities and adiabatic ionization enthalpies. Moreover, the results are also discussed in terms of the energetic effects of the addition of a carboxylic and of a methyl groups to the pyrrole ring and compared with structurally similar compounds.

  3. Chlorido{1-[(dimethylamino)methyl]ferrocenyl-κ2 C 2,N}(tri­phenyl­stibine-κSb)palladium(II)

    PubMed Central

    Pérez, Diego; Sharma, Pankaj; Sharma, Manju; Hernández, Simón

    2013-01-01

    In the title compound, [FePdCl(C5H5)(C8H11N)(C18H15Sb)], obtained by reaction of diphen­yl(N,N-di­methyl­amino­methyl­ferrocen­yl)stibine with sodium tetra­chlorido­palladate(II) in acetone, the PdII atom is coordinated in a slightly distorted square-planar geometry by a C atom of the ferrocenyl ring, and by N, Cl and Sb atoms. The Sb and N atoms are trans to each other. PMID:24046555

  4. DNA methylation status of cyp17-II gene correlated with its expression pattern and reproductive endocrinology during ovarian development stages of Japanese flounder (Paralichthys olivaceus).

    PubMed

    Ding, YuXia; He, Feng; Wen, HaiShen; Li, JiFang; Ni, Meng; Chi, MeiLi; Qian, Kun; Bu, Yan; Zhang, DongQian; Si, YuFeng; Zhao, JunLi

    2013-09-15

    Cytochrome P450c17-II (cyp17-II, 17α-hydroxylase) is responsible for the production of steroid hormones during oocyte maturation in vertebrates. The comparative expression pattern of cyp17-II gene during the gonadal development stages will provide important insights into its function of gonadal development. In addition, epigenetic modification especially DNA methylation plays a vital role in regulation of gene expression. The adult female Japanese flounder at different ovarian development stage (from stages II to V) was obtained in this experiment. The expression of cyp17-II gene in the ovary of Japanese flounder during the gonadal development stages was measured by quantitative PCR. Reproductive traits included gonadosomatic index (GSI), plasma estradiol-17β (E2) and testosterone (T) were also measured. Moreover, whole CpG dinucleotides methylation status of the two CpG rich regions in cyp17-II coding region was detected by bisulfate sequencing. In the ovary, the cyp17-II gene had the lowest mRNA expression at the early ovarian development stage, but then increased afterward. The variation trends of T and E2 level were consistent with the cyp17-II expression pattern in ovary. In contrast, the whole methylation levels of each CpG rich region (exon 4 and 6) in cyp17-II coding region were declined from stages II to IV, then increased at stage V. The methylation levels of whole CpG sites in each CpG rich region were inversely correlated with the values of ovarian cyp17-II gene expression, T and E2 level, and GSI. Based on the present study, we proposed that cyp17-II may regulate the level of steroid hormone, and then stimulate the oocyte growth and maturation. The cyp17-II gene transcriptional activity was possibly affected by the methylation level of CpG rich regions in coding region. These findings will help in the study of the molecular mechanism of fish reproduction and endocrine physiology.

  5. Bis(2-amino-5-methyl-1,3,4-thia­diazole-κN 3)dichloridocobalt(II)

    PubMed Central

    Song, Ye; Ji, Yu-Fei; Kang, Min-Yan; Liu, Zhi-Liang

    2012-01-01

    In the monomeric title complex, [CoCl2(C3H5N3S)2], the CoII atom is tetra­coordinated by two chloride anions and two N atoms from two monodentate 2-amino-5-methyl-1,3,4-thia­diazole ligands, giving a slightly distorted tetra­hedral stereochemistry [bond angle range about Co = 105.16 (12)–112.50 (10)°]. In the complex, the dihedral angle between the 1,3,4-thia­diazole planes in the two ligands is 72.8 (1)°. There are two intra­molecular N—H⋯Cl inter­actions in the complex unit, while in the crystal, inter­molecular N—H⋯N and N—H⋯Cl hydrogen bonds link these units into a two-dimensional layered structure parallel to (011). PMID:22719326

  6. Metal(II) complexes synthesized based on quinoline-2,3-dicarboxylate as electrocatalysts for the degradation of methyl orange.

    PubMed

    Gong, Yun; Zhang, Miao Miao; Qin, Jian Bo; Li, Jian; Meng, Jiang Ping; Lin, Jian Hua

    2014-06-14

    Based on quinoline-2,3-dicarboxylic acid (H2L), two metal(II) complexes formulated as MnL(phen)(H2O)·H2O (phen = 1,10-phenanthroline) (1) and Co(HL)2(PPA)·4H2O (PPA = N(1),N(4)-di(pyridin-4-yl)terephthalamide) (2) were synthesized and structurally characterized by single-crystal X-ray diffraction. Both complexes 1 and 2 exhibit one-dimensional (1D) chain-like structures, in which stable five-membered rings are observed. Different chains are linked by strong π-π stacking interactions into a three-dimensional (3D) supramolecular architecture. Both complexes can increase the degradation rate of methyl orange (MO), which is expected to be associated with their electrocatalytic activities for the H2 evolution reaction from water. PMID:24741675

  7. Glass polymorphism in glycerol–water mixtures: II. Experimental studies

    PubMed Central

    Bachler, Johannes; Fuentes-Landete, Violeta; Jahn, David A.; Wong, Jessina; Giovambattista, Nicolas

    2016-01-01

    We report a detailed experimental study of (i) pressure-induced transformations in glycerol–water mixtures at T = 77 K and P = 0–1.8 GPa, and (ii) heating-induced transformations of glycerol–water mixtures recovered at 1 atm and T = 77 K. Our samples are prepared by cooling the solutions at ambient pressure at various cooling rates (100 K s–1–10 K h–1) and for the whole range of glycerol mole fractions, χ g. Depending on concentration and cooling rates, cooling leads to samples containing amorphous ice (χ g ≥ 0.20), ice (χ g ≤ 0.32), and/or “distorted ice” (0 < χ g ≤ 0.38). Upon compression, we find that (a) fully vitrified samples at χ g ≥ 0.20 do not show glass polymorphism, in agreement with previous works; (b) samples containing ice show pressure-induced amorphization (PIA) leading to the formation of high-density amorphous ice (HDA). PIA of ice domains within the glycerol–water mixtures is shown to be possible only up to χ g ≈ 0.32 (T = 77 K). This is rather surprising since it has been known that at χ g < 0.38, cooling leads to phase-separated samples with ice and maximally freeze-concentrated solution of χ g ≈ 0.38. Accordingly, in the range 0.32 < χ g < 0.38, we suggest that the water domains freeze into an interfacial ice, i.e., a highly-distorted form of layered ice, which is unable to transform to HDA upon compression. Upon heating samples recovered at 1 atm, we observe a rich phase behavior. Differential scanning calorimetry indicates that only at χ g ≤ 0.15, the water domains within the sample exhibit polyamorphism, i.e., the HDA-to-LDA (low-density amorphous ice) transformation. At 0.15 < χ g ≤ 0.38, samples contain ice, interfacial ice, and/or HDA domains. All samples (χ g ≤ 0.38) show: the crystallization of amorphous ice domains, followed by the glass transition of the vitrified glycerol–water domains and, finally, the melting of ice at high temperatures. Our work exemplifies the complex

  8. Glass polymorphism in glycerol-water mixtures: II. Experimental studies.

    PubMed

    Bachler, Johannes; Fuentes-Landete, Violeta; Jahn, David A; Wong, Jessina; Giovambattista, Nicolas; Loerting, Thomas

    2016-04-28

    We report a detailed experimental study of (i) pressure-induced transformations in glycerol-water mixtures at T = 77 K and P = 0-1.8 GPa, and (ii) heating-induced transformations of glycerol-water mixtures recovered at 1 atm and T = 77 K. Our samples are prepared by cooling the solutions at ambient pressure at various cooling rates (100 K s(-1)-10 K h(-1)) and for the whole range of glycerol mole fractions, χ(g). Depending on concentration and cooling rates, cooling leads to samples containing amorphous ice (χg ≥ 0.20), ice (χ(g) ≤ 0.32), and/or "distorted ice" (0 < χ(g) ≤ 0.38). Upon compression, we find that (a) fully vitrified samples at χ(g) ≥ 0.20 do not show glass polymorphism, in agreement with previous works; (b) samples containing ice show pressure-induced amorphization (PIA) leading to the formation of high-density amorphous ice (HDA). PIA of ice domains within the glycerol-water mixtures is shown to be possible only up to χ(g) ≈ 0.32 (T = 77 K). This is rather surprising since it has been known that at χ(g) < 0.38, cooling leads to phase-separated samples with ice and maximally freeze-concentrated solution of χ(g) ≈ 0.38. Accordingly, in the range 0.32 < χ(g) < 0.38, we suggest that the water domains freeze into an interfacial ice, i.e., a highly-distorted form of layered ice, which is unable to transform to HDA upon compression. Upon heating samples recovered at 1 atm, we observe a rich phase behavior. Differential scanning calorimetry indicates that only at χ(g) ≤ 0.15, the water domains within the sample exhibit polyamorphism, i.e., the HDA-to-LDA (low-density amorphous ice) transformation. At 0.15 < χ(g) ≤ 0.38, samples contain ice, interfacial ice, and/or HDA domains. All samples (χ(g) ≤ 0.38) show: the crystallization of amorphous ice domains, followed by the glass transition of the vitrified glycerol-water domains and, finally, the melting of ice at high temperatures. Our work exemplifies the complex "phase" behavior

  9. Glass polymorphism in glycerol-water mixtures: II. Experimental studies.

    PubMed

    Bachler, Johannes; Fuentes-Landete, Violeta; Jahn, David A; Wong, Jessina; Giovambattista, Nicolas; Loerting, Thomas

    2016-04-28

    We report a detailed experimental study of (i) pressure-induced transformations in glycerol-water mixtures at T = 77 K and P = 0-1.8 GPa, and (ii) heating-induced transformations of glycerol-water mixtures recovered at 1 atm and T = 77 K. Our samples are prepared by cooling the solutions at ambient pressure at various cooling rates (100 K s(-1)-10 K h(-1)) and for the whole range of glycerol mole fractions, χ(g). Depending on concentration and cooling rates, cooling leads to samples containing amorphous ice (χg ≥ 0.20), ice (χ(g) ≤ 0.32), and/or "distorted ice" (0 < χ(g) ≤ 0.38). Upon compression, we find that (a) fully vitrified samples at χ(g) ≥ 0.20 do not show glass polymorphism, in agreement with previous works; (b) samples containing ice show pressure-induced amorphization (PIA) leading to the formation of high-density amorphous ice (HDA). PIA of ice domains within the glycerol-water mixtures is shown to be possible only up to χ(g) ≈ 0.32 (T = 77 K). This is rather surprising since it has been known that at χ(g) < 0.38, cooling leads to phase-separated samples with ice and maximally freeze-concentrated solution of χ(g) ≈ 0.38. Accordingly, in the range 0.32 < χ(g) < 0.38, we suggest that the water domains freeze into an interfacial ice, i.e., a highly-distorted form of layered ice, which is unable to transform to HDA upon compression. Upon heating samples recovered at 1 atm, we observe a rich phase behavior. Differential scanning calorimetry indicates that only at χ(g) ≤ 0.15, the water domains within the sample exhibit polyamorphism, i.e., the HDA-to-LDA (low-density amorphous ice) transformation. At 0.15 < χ(g) ≤ 0.38, samples contain ice, interfacial ice, and/or HDA domains. All samples (χ(g) ≤ 0.38) show: the crystallization of amorphous ice domains, followed by the glass transition of the vitrified glycerol-water domains and, finally, the melting of ice at high temperatures. Our work exemplifies the complex "phase" behavior

  10. Experimental design in analytical chemistry--part II: applications.

    PubMed

    Ebrahimi-Najafabadi, Heshmatollah; Leardi, Riccardo; Jalali-Heravi, Mehdi

    2014-01-01

    This paper reviews the applications of experimental design to optimize some analytical chemistry techniques such as extraction, chromatography separation, capillary electrophoresis, spectroscopy, and electroanalytical methods.

  11. Phase II metabolism in human skin: skin explants show full coverage for glucuronidation, sulfation, N-acetylation, catechol methylation, and glutathione conjugation.

    PubMed

    Manevski, Nenad; Swart, Piet; Balavenkatraman, Kamal Kumar; Bertschi, Barbara; Camenisch, Gian; Kretz, Olivier; Schiller, Hilmar; Walles, Markus; Ling, Barbara; Wettstein, Reto; Schaefer, Dirk J; Itin, Peter; Ashton-Chess, Joanna; Pognan, Francois; Wolf, Armin; Litherland, Karine

    2015-01-01

    Although skin is the largest organ of the human body, cutaneous drug metabolism is often overlooked, and existing experimental models are insufficiently validated. This proof-of-concept study investigated phase II biotransformation of 11 test substrates in fresh full-thickness human skin explants, a model containing all skin cell types. Results show that skin explants have significant capacity for glucuronidation, sulfation, N-acetylation, catechol methylation, and glutathione conjugation. Novel skin metabolites were identified, including acyl glucuronides of indomethacin and diclofenac, glucuronides of 17β-estradiol, N-acetylprocainamide, and methoxy derivatives of 4-nitrocatechol and 2,3-dihydroxynaphthalene. Measured activities for 10 μM substrate incubations spanned a 1000-fold: from the highest 4.758 pmol·mg skin(-1)·h(-1) for p-toluidine N-acetylation to the lowest 0.006 pmol·mg skin(-1)·h(-1) for 17β-estradiol 17-glucuronidation. Interindividual variability was 1.4- to 13.0-fold, the highest being 4-methylumbelliferone and diclofenac glucuronidation. Reaction rates were generally linear up to 4 hours, although 24-hour incubations enabled detection of metabolites in trace amounts. All reactions were unaffected by the inclusion of cosubstrates, and freezing of the fresh skin led to loss of glucuronidation activity. The predicted whole-skin intrinsic metabolic clearances were significantly lower compared with corresponding whole-liver intrinsic clearances, suggesting a relatively limited contribution of the skin to the body's total systemic phase II enzyme-mediated metabolic clearance. Nevertheless, the fresh full-thickness skin explants represent a suitable model to study cutaneous phase II metabolism not only in drug elimination but also in toxicity, as formation of acyl glucuronides and sulfate conjugates could play a role in skin adverse reactions.

  12. Synthesis, characterization, crystal structure determination and computational study of a new Cu(II) complex of bis [2-{(E)-[2-chloroethyl)imino]methyl}phenolato)] copper(II) Schiff base complex

    NASA Astrophysics Data System (ADS)

    Grivani, Gholamhossein; Vakili, Mohammad; Khalaji, Aliakbar Dehno; Bruno, Giuseppe; Rudbari, Hadi Amiri; Taghavi, Maedeh

    2016-07-01

    The copper (II) Schiff base complex of [CuL2] (1), HL = 2-{(E)-[2-chloroethyl) imino]methyl}phenol, has been synthesized and characterized by elemental (CHN) analysis, UV-Vis and FT-IR spectroscopy. The molecular structure of 1 was determined by single crystal X-ray diffraction technique. The conformational analysis and molecular structures of CuL2 were investigated by means of density functional theory (DFT) calculations at B3LYP/6-311G* level. An excellent agreement was observed between theoretical and experimental results. The Schiff base ligand of HL acts as a chelating ligand and coordinates via one nitrogen atom and one oxygen atom to the metal center. The copper (II) center is coordinated by two nitrogen atoms and two oxygen atoms from two Schiff base ligands in an approximately square planar trans-[MN2O2] coordination geometry. Thermogravimetric analysis of CuL2 showed that it was decomposed in five stages. In addition, the CuL2 complex thermally decomposed in air at 660 °C and the XRD pattern of the obtained solid showed the formation of CuO nanoparticles with an average size of 34 nm.

  13. Synthesis and Characterization of bis[(2-ethyl-5-methyl-imidazo-4-yl)methyl]Sulfide and Its Coordination Behavior toward Cu(II) as a Possible Approach of a Copper Site Type I

    PubMed Central

    Barrón-Garcés, Juan D.; Mendoza-Díaz, Guillermo; Vilchez-Aguado, Florina; Bernès, Sylvain

    2009-01-01

    The synthesis and characterization of a novel ligand, bis[(2-ethyl-5-methyl-imidazo-4-yl)methyl]sulfide (bemims), as well as a bemims-containing copper(II) coordination complex are described. In this complex, [Cu(bemims)X2] with X = NO3−, bemims acts as a tridentate ligand and two monodentate nitrate ions complete the coordination sphere. Both imidazole N atoms and the thioether S atom of bemims participate in coordination. The Cu(II) ion is five-coordinated with a slightly distorted square-pyramidal geometry (τ = .09). Electrochemical studies and spectroscopic data for this complex are compared with some blue copper proteins in order to assess its ability to mimic the copper center of type I copper proteins. PMID:19587830

  14. Global Analysis of H3K4 Methylation Defines MLL Family Member Targets and Points to a Role for MLL1-Mediated H3K4 Methylation in the Regulation of Transcriptional Initiation by RNA Polymerase II ▿ †

    PubMed Central

    Wang, Pengfei; Lin, Chengqi; Smith, Edwin R.; Guo, Hong; Sanderson, Brian W.; Wu, Min; Gogol, Madelaine; Alexander, Tara; Seidel, Christopher; Wiedemann, Leanne M.; Ge, Kai; Krumlauf, Robb; Shilatifard, Ali

    2009-01-01

    A common landmark of activated genes is the presence of trimethylation on lysine 4 of histone H3 (H3K4) at promoter regions. Set1/COMPASS was the founding member and is the only H3K4 methylase in Saccharomyces cerevisiae; however, in mammals, at least six H3K4 methylases, Set1A and Set1B and MLL1 to MLL4, are found in COMPASS-like complexes capable of methylating H3K4. To gain further insight into the different roles and functional targets for the H3K4 methylases, we have undertaken a genome-wide analysis of H3K4 methylation patterns in wild-type Mll1+/+ and Mll1−/− mouse embryonic fibroblasts (MEFs). We found that Mll1 is required for the H3K4 trimethylation of less than 5% of promoters carrying this modification. Many of these genes, which include developmental regulators such as Hox genes, show decreased levels of RNA polymerase II recruitment and expression concomitant with the loss of H3K4 methylation. Although Mll1 is only required for the methylation of a subset of Hox genes, menin, a component of the Mll1 and Mll2 complexes, is required for the overwhelming majority of H3K4 methylation at Hox loci. However, the loss of MLL3/MLL4 and/or the Set1 complexes has little to no effect on the H3K4 methylation of Hox loci or their expression levels in these MEFs. Together these data provide insight into the redundancy and specialization of COMPASS-like complexes in mammals and provide evidence for a possible role for Mll1-mediated H3K4 methylation in the regulation of transcriptional initiation. PMID:19703992

  15. Experimentation on prisoners by the Japanese during World War II.

    PubMed

    Girdwood, Ronald H

    1985-08-24

    Girdwood, president of the Royal College of Physicians of Edinburgh, recounts his experience in assessing and treating newly released Allied prisoners in the Far East during World War II. Although he had been posted to various locales and had interviewed many prison camp survivors, he had not heard direct accounts of germ warfare experiments allegedly performed by the Japanese on American, British, and Australian prisoners until they were reported on a British television program, Unit 731, on 13 August 1985. While poor medical care, abuse, and malnutrition were known, information about biological warfare disclosed on the television program was evidently not known to British, Indian, or Australian authorities until the war's end.

  16. {2-[(Benzylphenyl-phosphanyl-κP)methyl]phenyl-κC}iodidobis(trimethyl-phos-phane)cobalt(II).

    PubMed

    Jia, Jiong; Wang, Chenggen; Liu, Nazhen; Li, Xiaoyan

    2011-07-01

    In the title compound, [Co(C(20)H(18)P)I(C(3)H(9)P)(2)], the Co(II) atom has a distorted square-pyramidal geometry, the base of which is comprised of two trans PMe(3) groups, an I atom, and a C atom of the benzyl group. This benzyl group is tethered to the P atom at the apex of the pyramid, thereby forming a five-membered chelated Co-C-C-C-P ring. PMID:21836963

  17. Sphericity measurements by the radial method: II. Experimental verification

    NASA Astrophysics Data System (ADS)

    Janecki, D.; Stępień, K.; Adamczak, S.

    2016-01-01

    The new concept of sphericity measurements enables accurate measurement of spherical elements. This concept assumes that measurements can be performed using a typical radial roundness measuring instrument equipped with a special mechanism for controlled positioning of a measured element. The concept requires solving numerous theoretical problems, and this was described in the previous companion paper. This second paper discusses the measuring equipment and the results of the experimental verification of the concept.

  18. Synthesis, Characterization, and Biological Activity of N′-[(Z)-(3-Methyl-5-oxo-1-phenyl-1,5-dihydro-4H-pyrazol-4-ylidene)(phenyl)methyl]benzohydrazide and Its Co(II), Ni(II), and Cu(II) Complexes

    PubMed Central

    Asegbeloyin, Jonnie N.; Ujam, Oguejiofo T.; Okafor, Emmanuel C.; Babahan, Ilknur; Coban, Esin Poyrazoglu; Özmen, Ali; Biyik, Halil

    2014-01-01

    Reaction of 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one and benzoyl hydrazide in refluxing ethanol gave N′-[(Z)-(3-methyl-5-oxo-1-phenyl-1,5-dihydro-4H-pyrazol-4-ylidene)(phenyl)methyl]benzohydrazide (HL1), which was characterized by NMR spectroscopy and single-crystal X-ray structure study. X-ray diffraction analyses of the crystals revealed a nonplanar molecule, existing in the keto-amine form, with intermolecular hydrogen bonding forming a seven-membered ring system. The reaction of HL1 with Co(II), Ni(II), and Cu(II) halides gave the corresponding complexes, which were characterized by elemental analysis, molar conductance, magnetic measurements, and infrared and electronic spectral studies. The compounds were screened for their in vitro cytotoxic activity against HL-60 human promyelocytic leukemia cells and antimicrobial activity against some bacteria and yeasts. Results showed that the compounds are potent against HL-60 cells with the IC50 value ≤5 μM, while some of the compounds were active against few studied Gram-positive bacteria. PMID:25332694

  19. Thermoelastic temperature changes in poly(methyl methacrylate) at high hydrostatic pressure: Experimental

    NASA Astrophysics Data System (ADS)

    Rodriquez, E. L.; Filisko, F. E.

    1982-10-01

    Temperature changes as a result of large rapid hydrostatic pressure changes were measured for poly(methyl methacrylate) at various temperatures from ambient to 95 °C and for various pressure increments from 14 to 207 MN/m2. We observe complete reversibility of the measurements over the pressure range studied. The value of the incremental ratio ΔT/ΔP was a function of both temperature and pressure, ranging from 0.04 to 0.09 K/MNm-2 from 298 to 368 K at low pressures, and 0.03-0.05 at 200 MN/m2 over the same temperature range. The largest variation of ΔT/ΔP with pressure was at low pressures, the ratio becoming nearly constant above about 200 MN/M2.

  20. Instrumentation and control improvements at Experimental Breeder Reactor II

    SciTech Connect

    Christensen, L.J.; Planchon, H.P.

    1993-01-01

    The purpose of this paper is to describe instrumentation and control (I C) system improvements at Experimental Breeder Reactor 11 (EBR-11). The improvements are focused on three objectives; to keep the reactor and balance of plant (BOP) I C systems at a high level of reliability, to provide diagnostic systems that can provide accurate information needed for analysis of fuel performance, and to provide systems that will be prototypic of I C systems of the next generation of liquid metal reactor (LMR) plants.

  1. Instrumentation and control improvements at Experimental Breeder Reactor II

    SciTech Connect

    Christensen, L.J.; Planchon, H.P.

    1993-03-01

    The purpose of this paper is to describe instrumentation and control (I&C) system improvements at Experimental Breeder Reactor 11 (EBR-11). The improvements are focused on three objectives; to keep the reactor and balance of plant (BOP) I&C systems at a high level of reliability, to provide diagnostic systems that can provide accurate information needed for analysis of fuel performance, and to provide systems that will be prototypic of I&C systems of the next generation of liquid metal reactor (LMR) plants.

  2. A high molar extinction coefficient bisterpyridyl homoleptic ru(II) complex with trans-2-methyl-2-butenoic acid functionality: potential dye for dye-sensitized solar cells.

    PubMed

    Adeloye, Adewale O; Olomola, Temitope O; Adebayo, Akinbulu I; Ajibade, Peter A

    2012-01-01

    In our continued efforts in the synthesis of ruthenium(II) polypyridine complexes as potential dyes for use in varied applications, such as the dye-sensitized solar cells (DSSCs), this work particularly describes the synthesis, absorption spectrum, redox behavior and luminescence properties of a new homoleptic ruthenium(II) complex bearing a simple trans-2-methyl-2-butenoic acid functionality as the anchoring ligand on terpyridine moiety. The functionalized terpyridine ligand: 4'-(trans-2-methyl-2-butenoic acid)-terpyridyl (L1) was synthesized by aryl bromide substitution on terpyridine in a basic reaction condition under palladium carbide catalysis. In particular, the photophysical and redox properties of the complex formulated as: bis-4'-(trans-2-methyl-2-butenoic acid)-terpyridyl ruthenium(II) bis-hexafluorophosphate [Ru(L1)(2)(PF(6))(2)] are significantly better compared to those of [Ru(tpy)(2)](2+) and compare well with those of the best emitters of Ru(II) polypyridine family containing tridentate ligands. Reasons for the improved photophysical and redox properties of the complex may be attributed partly to the presence of a substituted α,β-unsaturated carboxylic acid moiety leading to increase in the length of π-conjugation bond thereby enhancing the MLCT-MC (Metal-to-ligand-charge transfer-metal centred) energy gap, and to the reduced difference between the minima of the excited and ground states potential energy surfaces.

  3. A High Molar Extinction Coefficient Bisterpyridyl Homoleptic Ru(II) Complex with trans-2-Methyl-2-butenoic Acid Functionality: Potential Dye for Dye-Sensitized Solar Cells

    PubMed Central

    Adeloye, Adewale O.; Olomola, Temitope O.; Adebayo, Akinbulu I.; Ajibade, Peter A.

    2012-01-01

    In our continued efforts in the synthesis of ruthenium(II) polypyridine complexes as potential dyes for use in varied applications, such as the dye-sensitized solar cells (DSSCs), this work particularly describes the synthesis, absorption spectrum, redox behavior and luminescence properties of a new homoleptic ruthenium(II) complex bearing a simple trans-2-methyl-2-butenoic acid functionality as the anchoring ligand on terpyridine moiety. The functionalized terpyridine ligand: 4′-(trans-2-methyl-2-butenoic acid)-terpyridyl (L1) was synthesized by aryl bromide substitution on terpyridine in a basic reaction condition under palladium carbide catalysis. In particular, the photophysical and redox properties of the complex formulated as: bis-4′-(trans-2-methyl-2-butenoic acid)-terpyridyl ruthenium(II) bis-hexafluorophosphate [Ru(L1)2(PF6)2] are significantly better compared to those of [Ru(tpy)2]2+ and compare well with those of the best emitters of Ru(II) polypyridine family containing tridentate ligands. Reasons for the improved photophysical and redox properties of the complex may be attributed partly to the presence of a substituted α,β-unsaturated carboxylic acid moiety leading to increase in the length of π-conjugation bond thereby enhancing the MLCT-MC (Metal-to-ligand-charge transfer-metal centred) energy gap, and to the reduced difference between the minima of the excited and ground states potential energy surfaces. PMID:22489165

  4. Cleavage of an RNA analog by Zn(II) macrocyclic catalysts appended with a methyl or an acridine group.

    PubMed

    Rossiter, Clifford S; Mathews, Ryan A; Morrow, Janet R

    2007-06-01

    Two macrocycles (1 and 2) are prepared that incorporate pendent groups in macrocycle 3 (3=1-oxa-4,7,10-triazacyclododecane) with the goal of studying the effect of these pendent groups on metal ion complexation, solution chemistry and catalysis. Zn(1) contains a macrocyclic ligand with a pendent acridine group and Zn(2) has an appended methyl group. Water ligand pK(a) values for Zn(1) (6.7) and Zn(2) (7.3) are lower than that of Zn(3) (7.7). Zn(II) complexes of 1 and 2 are studied as catalysts for the cleavage of 2-hydroxypropyl 4-nitrophenylphosphate (HpPNP), an RNA analog. Zn(2) has a lower catalytic activity over the pH range 7-10 for cleavage of HpPNP compared to the parent macrocyclic complex, Zn(3). In contrast, Zn(1) has a threefold larger rate constant at pH 7.0 compared to Zn(2), attributed to the presence of a catalytic species which has a protonated acridine amino group. The binding constant of 1.5mM at pH 8.0 for formation of the Zn(2)-uridine adduct is similar to that for Zn(3), suggesting that N-alkylation of the macrocyclic ligand does not interfere with binding of the Zn(II) complex to uridine groups. Binding of cytidine to Zn(2) was not detectable under similar conditions up to 25mM nucleoside. Binding experiments under similar conditions could not be carried out for adenosine or guanosine due to their low solubility.

  5. Poly[bis­{μ-N′-[(pyridin-4-yl)methyl­idene]benzohydrazidato}copper(II)

    PubMed Central

    Wu, Qiong; Chen, Da-Chi; Wu, Chu-Yi; Yan, Chang-Xiu; Liao, Jian-Zhen

    2013-01-01

    In the title complex, [Cu(C13H10N3O)2]n, the copper(II) cation is located on a crystallographic inversion centre and adopts an elongated octa­hedral coordination geometry with the equatorial plane provided by trans-arranged bis-N,O-chelating acyl­hydrazine groups from two ligands and the apices by the N atoms of two pyridine rings belonging to symmetry-related ligands. The ligand adopts a Z conformation about the C=N double bond. The dihedral angle between the pyridine and phenyl rings is 2.99 (13)°. An intra­ligand C—H⋯N hydrogen bond is observed. In the crystal, each ligand bridges two adjacent metal ions, forming a (4,4) grid layered structure. π–π stacking inter­actions [centroid–centroid distances in the range 3.569 (4)–3.584 (9) Å] involving rings of adjacent layers result in the formation of a three-dimensional supra­molecular network. PMID:24046562

  6. A Multifunctional Mn(II) Phosphonate for Rapid Separation of Methyl Orange and Electron-Transfer Photochromism.

    PubMed

    Gao, Chao-Ying; Yang, Yang; Ai, Jing; Tian, Hong-Rui; Li, Lei-Jiao; Yang, Weiting; Dang, Song; Sun, Zhong-Ming

    2016-08-01

    A Mn(II) phosphonate of the general formula [Mn(H2 L)2 (H2 O)2 (H2 bibp)] adopts a layered motif with protonated H2 bibp(2+) cations embedded in the channels (H4 L=thiophene-2-phosphonic acid; bibp=4,4'-bis(1-imidazolyl)biphenyl). The title compound exhibits excellent adsorptive removal of methyl orange (MO) dye from aqueous solution. Its advantageous features include fast adsorption, high uptake capacity, selective removal, and reusability, which are of great significance for practical application in wastewater treatment. Meanwhile, the compound displays rapid photochromism upon irradiation with visible light at room temperature. Extensive research has demonstrated that such behavior is based on a ligand-to-ligand charge-transfer (LLCT) mechanism. The irradiated sample possesses an ultra-long-lived charge-separated state. Moreover, not only is the compound the first Mn-based photochromic MOF, but it is also one of the very few examples showing LLCT with non-photochromic components. PMID:27374008

  7. Anthelmintic profile of methyl 5(6)-(4-methylpiperidin-1-yl) carbonylbenzimidazole-2-carbamate in experimental helminthiases.

    PubMed

    Gupta, S; Khan, A M; Jain, M K; Katiyar, J C; Naim, S S; Singh, S K; Sharma, S

    1990-05-01

    Biological evaluation of methyl 5(6)-(4-methylpiperidin-1-yl) carbonylbenzimidazole-2-carbamate against Ancylostoma ceylanicum, Nippostrongylus brasiliensis, Syphacia obvelata, Hymenolepis nana, H. diminuta and Cysticercus fasciolaris in experimental animals is reported. The compound (mg/kg) causes 100% elimination of A. ceylanicum (25 x 1), N. brasiliensis (100 x 1), S. obvelata (50 x 1), H. nana (250 x 3) and C. fasciolaris (50 x 10). It was also effective against the developing larvae (L3, L4 and L5) of A. ceylanicum at a single oral dose of 100 mg/kg. Another study indicated that the compound elicits 100% response within 32 hr of drug administration. The drug is well tolerated and LD50 is greater than 4500 mg/kg.

  8. Theoretical and experimental studies of phenol oxidation by ruthenium complex with N,N,N-tris(benzimidazol-2yl-methyl)amine.

    PubMed

    Hernandez, J Guadalupe; Silva, Antonio Romero; Thangarasu, Pandiyan; Najera, Rafael Herrera; Moreno, Alfonso Duran; Ledesma, M Teresa Orta; Cruz-Borbolla, Julian; Singh, Narinder

    2015-09-01

    The ruthenium complex with (N,N,N-tris(benzimidazol-2yl-methyl)amine, L(1)) was prepared, and characterized. Fukui data were used to localize the reactive sites on the ligand. The structural and electronic properties of the complex were analyzed by DFT in different oxidation states in order to evaluate its oxidant properties for phenol oxidation. The results show that the hard Ru(IV) cation bonds preferentially with a hard base (Namine = amine nitrogen, or axial chloride ion), and soft Ru(II) with a soft base (Nbzim = benzimidazole nitrogen or axial triphenyl phosphine). Furthermore, the Jahn-Teller effect causes an elongation of the axial bond in the octahedral structure. The bonding nature and the orbital contribution to the electronic transitions of the complex were studied. The experimental UV-visible bands were interpreted by using TD-DFT studies. The complex oxidizes phenol to benzoquinone in the presence of H2O2 and the intermediate was detected by HPLC and (13)C NMR. A possible mechanism and rate law are proposed for the oxidation. The adduct formation of phenol with [Ru(O)L(1)](2+) or [Ru(OH)L(1)](+) is theoretically analyzed to show that [Ru(OH)L(1)-OPh](+) could produce the phenol radical.

  9. Theoretical and experimental studies of phenol oxidation by ruthenium complex with N,N,N-tris(benzimidazol-2yl-methyl)amine.

    PubMed

    Hernandez, J Guadalupe; Silva, Antonio Romero; Thangarasu, Pandiyan; Najera, Rafael Herrera; Moreno, Alfonso Duran; Ledesma, M Teresa Orta; Cruz-Borbolla, Julian; Singh, Narinder

    2015-09-01

    The ruthenium complex with (N,N,N-tris(benzimidazol-2yl-methyl)amine, L(1)) was prepared, and characterized. Fukui data were used to localize the reactive sites on the ligand. The structural and electronic properties of the complex were analyzed by DFT in different oxidation states in order to evaluate its oxidant properties for phenol oxidation. The results show that the hard Ru(IV) cation bonds preferentially with a hard base (Namine = amine nitrogen, or axial chloride ion), and soft Ru(II) with a soft base (Nbzim = benzimidazole nitrogen or axial triphenyl phosphine). Furthermore, the Jahn-Teller effect causes an elongation of the axial bond in the octahedral structure. The bonding nature and the orbital contribution to the electronic transitions of the complex were studied. The experimental UV-visible bands were interpreted by using TD-DFT studies. The complex oxidizes phenol to benzoquinone in the presence of H2O2 and the intermediate was detected by HPLC and (13)C NMR. A possible mechanism and rate law are proposed for the oxidation. The adduct formation of phenol with [Ru(O)L(1)](2+) or [Ru(OH)L(1)](+) is theoretically analyzed to show that [Ru(OH)L(1)-OPh](+) could produce the phenol radical. PMID:26252971

  10. Co(II), Ni(II) and Cu(II) complexes of methyl-5-(Phenylthio) benzimidazole-2-carbamate: Molecular structures, spectral and DFT calculations

    NASA Astrophysics Data System (ADS)

    Mansour, Ahmed M.; El Bakry, Eslam M.; Abdel-Ghani, Nour T.

    2016-05-01

    [Co(FBZ)2(H2O)]·2NO3·0.5H2O (1), [Ni(FBZ)2X2]·zH2O (X = Cl​-, z = 0.5 (2) and X = CH3COO-, z = 1 (3)) and [Cu(FBZ)2(H2O) (NO3)]·NO3·1.5H2O (4) (FBZ = methyl-5-(Phenylthio) benzimidazole-2-carbamate; Fenbendazole) complexes were synthesized and characterized by elemental analysis, thermal, IR, EPR, UV-Vis, magnetic and conductance measurements. Geometry optimization, molecular electrostatic potential maps and natural bond orbital analysis were carried out at DFT/B3LYP/6-31G∗ level of theory. FBZ behaves as a neutral bidentate ligand via the pyridine-type nitrogen of the benzimidazole moiety and the carbamate group. Three-step ionization with pKa values of 3.38, 4.06 and 10.07 were reported for FBZ. The coordination of FBZ to the metal ions led to an increase in the antibacterial activity against the tested Staphylococcus aureus and Escherichia coli bacteria.

  11. Poly[(μ3-camphorato-κ3 O:O′:O′′)(2-methyl-1H-imidazole-κN 3)zinc(II)

    PubMed Central

    Shi, Haochen; Li, Chunjie; Gao, Feng; Chen, Jingyan; Han, Fei

    2010-01-01

    In the title compound, [Zn(C10H14O4)(C4H6N2)]n, each ZnII ion is coordinated by one N atom from one 2-methyl-1H-imidazole ligand and three O atoms from two camphorate (cap) ligands in a distorted tetra­hedral geometry. In one of the cap ligands, one methyl group is disordered between positions 1 and 3 in a 0.518 (12):0.482 (12) ratio. Each cap ligand bridges three ZnII ions, forming two-dimensional layers, which inter­act further via N—H⋯O hydrogen bonds. PMID:21580467

  12. Experimental study on the enhancement of the neurotoxicity of methyl n-butyl ketone by non-neurotoxic aliphatic monoketones.

    PubMed Central

    Misumi, J; Nagano, M

    1985-01-01

    The neurotoxicity of methyl n-butyl ketone is known to be enhanced by combination with methyl ethyl ketone. This study was conducted to clarify the potentiating effect of aliphatic monoketones on the neurotoxicity of methyl n-butyl ketone. Rats were subcutaneously injected in the back with 4 mmol/kg/day of methyl ethyl ketone, methyl n-propyl ketone, methyl n-amyl ketone, or methyl n-hexyl ketone mixed with an equimolar dose of methyl n-butyl ketone five days a week for 20 weeks. The maximum motor fibre conduction velocity and the distal latency were measured every two weeks in the tail nerves of the treated animals and controls. All the monoketones tested enhanced the neurotoxicity of methyl n-butyl ketone. Of the compounds tested, methyl n-hexyl ketone, which had the longest carbon chain, enhanced the neurotoxicity of methyl n-butyl ketone most strongly. These results suggest that the length of the carbon chain of the aliphatic monoketones combined with methyl n-butyl ketone was related to the enhancement of the neurotoxicity of the neurotoxic compound. PMID:3970879

  13. Crystal structure of bis­(N,N,N′,N′-tetra­methyl­guanidinium) tetra­chlorido­cuprate(II)

    PubMed Central

    Ndiaye, Mamadou; Samb, Abdoulaye; Diop, Libasse; Maris, Thierry

    2016-01-01

    In the structure of the title salt, (C5H14N3)2[CuCl4], the CuII atom in the anion lies on a twofold rotation axis. The tetra­chlorido­cuprate(II) anion adopts a flattened tetra­hedral coordination environment and inter­acts electrostatically with the tetra­methyl­guanidinium cation. The crystal packing is additionally consolidated through N—H⋯Cl and C—H⋯Cl hydrogen bonds, resulting in a three-dimensional network structure. PMID:27555960

  14. Methodological considerations regarding the use of inorganic 197Hg(II) radiotracer to assess mercury methylation potential rates in lake sediment.

    PubMed

    Pérez Catán, Soledad; Guevara, Sergio Ribeiro; Marvin-DiPasquale, Mark; Magnavacca, Cecilia; Cohen, Isaac Marcos; Arribere, María

    2007-09-01

    Methodological considerations on the determination of benthic methyl-mercury (CH(3)Hg) production potentials were investigated on lake sediment, using (197)Hg radiotracer. Three methods to arrest bacterial activity were compared: flash freezing, thermal sterilization, and gamma-irradiation. Flash freezing showed similar CH(3)Hg recoveries as thermal sterilization, which was both 50% higher than the recoveries obtained with gamma-ray irradiation. No additional radiolabel was recovered in kill-control samples after an additional 24 or 65 h of incubation, suggesting that all treatments were effective at arresting Hg(II)-methylating bacterial activity, and that the initial recoveries are likely due to non-methylated (197)Hg(II) carry-over in the organic extraction and/or [(197)Hg]CH(3)Hg produced via abiotic reactions. Two CH(3)Hg extraction methods from sediment were compared: (a) direct extraction into toluene after sediment leaching with CuSO(4) and HCl and (b) the same extraction with an additional back-extraction step to thiosulphate. Similar information was obtained with both methods, but the low efficiency observed and the extra work associated with the back-extraction procedure represent significant disadvantages, even tough the direct extraction involves higher Hg(II) carry over.

  15. Methodological considerations regarding the use of inorganic 197Hg(II) radiotracer to assess mercury methylation potential rates in lake sediment

    USGS Publications Warehouse

    Perez, Catan S.; Guevara, S.R.; Marvin-DiPasquale, M.; Magnavacca, C.; Cohen, I.M.; Arribere, M.

    2007-01-01

    Methodological considerations on the determination of benthic methyl-mercury (CH3Hg) production potentials were investigated on lake sediment, using 197Hg radiotracer. Three methods to arrest bacterial activity were compared: flash freezing, thermal sterilization, and ??-irradiation. Flash freezing showed similar CH3Hg recoveries as thermal sterilization, which was both 50% higher than the recoveries obtained with ??-ray irradiation. No additional radiolabel was recovered in kill-control samples after an additional 24 or 65 h of incubation, suggesting that all treatments were effective at arresting Hg(II)-methylating bacterial activity, and that the initial recoveries are likely due to non-methylated 197Hg(II) carry-over in the organic extraction and/or [197Hg]CH3Hg produced via abiotic reactions. Two CH3Hg extraction methods from sediment were compared: (a) direct extraction into toluene after sediment leaching with CuSO4 and HCl and (b) the same extraction with an additional back-extraction step to thiosulphate. Similar information was obtained with both methods, but the low efficiency observed and the extra work associated with the back-extraction procedure represent significant disadvantages, even tough the direct extraction involves higher Hg(II) carry over. ?? 2007 Elsevier Ltd. All rights reserved.

  16. Electrochemistry and photocurrents of the tris(bipyridine)ruthenium(II) and methyl viologen cations immobilized in carrageenan hydrogel. [tris(2,2'-bipyridine)ruthenium(II)

    SciTech Connect

    Rillema, D.P.; Edwards, A.K. ); Perine, S.C.; Crumbliss, A.L. )

    1991-11-13

    A procedure for immobilization of both a photochromophore, tris(2,2{prime}-bipyridine)ruthenium(II) (Ru(bpy){sub 3}{sup 2+}), and a quencher, methyl viologen (MV{sup 2+}), within a carrageenan hydrogel matrix at an electrode surface is described. Ru(bpy){sub 3}{sup 2+} and MV{sup 2+} exhibited diffusion coefficients that ranged from 10{sup {minus} 7} to 10{sup {minus} 6} cm{sup 2}/s in the hydrogel, which represents an improvement over other immobilization matrices. Photolysis of the resulting hydrogel surface modified electrodes gave rise to a significant photocurrent which depended on the concentrations of Ru(bpy){sub 3}{sup 2+}, MV{sup 2+}, and triethanolamine and resulted in a maximum value of 12 {mu}A/cm{sup 2} after the hydrogel was cured with a solution containing 5 mM Ru(bpy){sub 3}{sup 2+} and 50 mM MV{sup 2+}. The photocurrent was the result of reoxidation of MV{sup +} at the electrode surface following reduction of MV{sup 2+} by photoexcited Ru(bpy){sub 3}{sup 2+}. The quenching rate constant of Ru(bpy){sub 3}{sup 2+} by MV{sup 2+} in the hydrogel was 4.2 {times} 10{sup 8} M{sup {minus}1} s{sup {minus}1}. The photocurrent action spectrum was consistent with Ru(bpy){sub 3}{sup 2+} acting as the photochromophore. Offsetting the potential of the hydrogel electrode verified the role of the MV{sup 2+}/{sup +} redox couple as the source of the current.

  17. Combination of angiotensin II and l-NG-nitroarginine methyl ester exacerbates mitochondrial dysfunction and oxidative stress to cause heart failure.

    PubMed

    Hamilton, Dale J; Zhang, Aijun; Li, Shumin; Cao, Tram N; Smith, Jessie A; Vedula, Indira; Cordero-Reyes, Andrea M; Youker, Keith A; Torre-Amione, Guillermo; Gupte, Anisha A

    2016-03-15

    Mitochondrial dysfunction has been implicated as a cause of energy deprivation in heart failure (HF). Herein, we tested individual and combined effects of two pathogenic factors of nonischemic HF, inhibition of nitric oxide synthesis [with l-N(G)-nitroarginine methyl ester (l-NAME)] and hypertension [with angiotensin II (AngII)], on myocardial mitochondrial function, oxidative stress, and metabolic gene expression. l-NAME and AngII were administered individually and in combination to mice for 5 wk. Although all treatments increased blood pressure and reduced cardiac contractile function, the l-NAME + AngII group was associated with the most severe HF, as characterized by edema, hypertrophy, oxidative stress, increased expression of Nppa and Nppb, and decreased expression of Atp2a2 and Camk2b. l-NAME + AngII-treated mice exhibited robust deterioration of cardiac mitochondrial function, as observed by reduced respiratory control ratios in subsarcolemmal mitochondria and reduced state 3 levels in interfibrillar mitochondria for complex I but not for complex II substrates. Cardiac myofibrils showed reduced ADP-supported and oligomycin-inhibited oxygen consumption. Mitochondrial functional impairment was accompanied by reduced mitochondrial DNA content and activities of pyruvate dehydrogenase and complex I but increased H2O2 production and tissue protein carbonyls in hearts from AngII and l-NAME + AngII groups. Microarray analyses revealed the majority of the gene changes attributed to the l-NAME + AngII group. Pathway analyses indicated significant changes in metabolic pathways, such as oxidative phosphorylation, mitochondrial function, cardiac hypertrophy, and fatty acid metabolism in l-NAME + AngII hearts. We conclude that l-NAME + AngII is associated with impaired mitochondrial respiratory function and increased oxidative stress compared with either l-NAME or AngII alone, resulting in nonischemic HF.

  18. A high temperature and atmospheric pressure experimental and detailed chemical kinetic modelling study of 2-methyl furan oxidation

    PubMed Central

    Somers, Kieran P.; Simmie, John M.; Gillespie, Fiona; Burke, Ultan; Connolly, Jessica; Metcalfe, Wayne K.; Battin-Leclerc, Frédérique; Dirrenberger, Patricia; Herbinet, Olivier; Glaude, Pierre-Alexandre; Curran, Henry J.

    2013-01-01

    An experimental ignition delay time study for the promising biofuel 2-methyl furan (2MF) was performed at equivalence ratios of 0.5, 1.0 and 2.0 for mixtures of 1% fuel in argon in the temperature range 1200–1800 K at atmospheric pressure. Laminar burning velocities were determined using the heat-flux method for mixtures of 2MF in air at equivalence ratios of 0.55–1.65, initial temperatures of 298–398 K and atmospheric pressure. A detailed chemical kinetic mechanism consisting of 2059 reactions and 391 species has been constructed to describe the oxidation of 2MF and is used to simulate experiment. Accurate reproduction of the experimental data has been obtained over all conditions with the developed mechanism. Rate of production and sensitivity analyses have been carried out to identify important consumption pathways of the fuel and key kinetic parameters under these conditions. The reactions of hydrogen atom with the fuel are highlighted as important under all experimental conditions studied, with abstraction by the hydrogen atom promoting reactivity and hydrogen atom addition to the furan ring inhibiting reactivity. This work, to the authors knowledge, is the first to combine theoretical and experimental work to describe the oxidation of any of the alkylated furans. The mechanism developed herein to describe 2MF combustion should also function as a sub-mechanism to describe the oxidation of 2,5-dimethyl furan whilst also providing key insights into the oxidation of this similar biofuel candidate. PMID:23814505

  19. Synthesis, Characterization and Thermal Studies of Zn(II), Cd(II) and Hg(II) Complexes of N-Methyl-N-Phenyldithiocarbamate: The Single Crystal Structure of [(C6H5)(CH3)NCS2]4Hg2

    PubMed Central

    Onwudiwe, Damian C.; Ajibade, Peter A.

    2011-01-01

    Zn(II), Cd(II) and Hg(II) complexes of N-methyl-N-phenyl dithiocarbamate have been synthesized and characterized by elemental analysis and spectral studies (IR, 1H and 13C-NMR). The single crystal X-ray structure of the mercury complex revealed that the complex contains a Hg centre with a distorted tetrahedral coordination sphere in which the dinuclear Hg complex resides on a crystallographic inversion centre and each Hg atom is coordinated to four S atoms from the dithiocarbamate moiety. One dithiocarbamate ligand acts as chelating ligand while the other acts as chelating bridging ligand between two Hg atoms, resulting in a dinuclear eight-member ring. The course of the thermal degradation of the complexes has been investigated using thermogravimetric and differential thermal analyses techniques. Thermogravimetric analysis of the complexes show a single weight loss to give MS (M = Zn, Cd, Hg) indicating that they might be useful as single source precursors for the synthesis of MS nanoparticles and thin films. PMID:21673933

  20. Seventeen years of LMFBR experience: Experimental Breeder Reactor II (EBR-II)

    SciTech Connect

    Perry, W.H.; Lentz, G.L.; Richardson, W.J.; Wolz, G.C.

    1982-01-01

    Operating experience at EBR-II over the past 17 years has shown that a sodium-cooled pool-type reactor can be safely and efficiently operated and maintained. The reactor has performed predictably and benignly during normal operation and during both unplanned and planned plant upsets. The duplex-tube evaporators and superheaters have never experienced a sodium/water leak, and the rest of the steam-generating system has operated without incident. There has been no noticeable degradation of the heat transfer efficiency of the evaporators and superheaters, except for the one superheater replaced in 1981. There has been no need to perform any chemical cleaning of steam-system components.

  1. Bis[2-(2H-benzotriazol-2-yl)-4-methyl-6-(phenyl­imino­methyl-κN)phenolato-κO]palladium(II)

    PubMed Central

    Su, Jing-Kai; Li, Chen-Yu; Ko, Bao-Tsan

    2011-01-01

    In the title complex, [Pd(C20H15N4O)2], the PdII atom is tetra­coordinated by two N atoms and two O atoms from two bidentate imine–benzotriazole phenolate ligands, forming a square-planar environment. The asymmetric unit contains two half-mol­ecules in both of which the PdII atom lies on a centre of symmetry. The average distances between the PdII atom and the coordinated O and N atoms are 1.9831 (12) and 2.012 (2) Å, respectively. PMID:22199607

  2. An experimental study of gaseous exhaust emissions of diesel engine using blend of natural fatty acid methyl ester

    NASA Astrophysics Data System (ADS)

    Sudrajad, Agung; Ali, Ismail; Samo, Khalid; Faturachman, Danny

    2012-09-01

    Vegetable oil form in Natural Fatty Acid Methyl Ester (FAME) has their own advantages: first of all they are available everywhere in the world. Secondly, they are renewable as the vegetables which produce oil seeds can be planted year after year. Thirdly, they are friendly with our environment, as they seldom contain sulphur element in them. This makes vegetable fuel studies become current among the various popular investigations. This study is attempt to optimization of using blend FAME on diesel engine by experimental laboratory. The investigation experimental project is comparison between using blend FAME and base diesel fuel. The engine experiment is conducted with YANMAR TF120M single cylinder four stroke diesel engine set-up at variable engine speed with constant load. The data have been taken at each point of engine speed during the stabilized engine-operating regime. Measurement of emissions parameters at difference engine speed conditions have generally indicated lower in emission NOx, but slightly higher on CO2 emission. The result also shown that the blends FAME are good in fuel consumption and potentially good substitute fuels for diesel engine

  3. Systematic experimental study of the Stark broadening of C II, C III, N II, N III, O II and O III spectral lines

    SciTech Connect

    Blagojevic, B.; Popovic, M. V.; Konjevic, N.

    1999-04-01

    We report the experimental Stark widths of plasma broadened lines belonging to 3s-3p and 3p-3d transitions of singly and doubly ionized C, N and O emitters. The light source was a low pressure pulsed arc. The plasma electron densities were determined from the width of the Hell P{sub {alpha}} line while the electron temperatures were measured from the relative line intensities of five N II spectral lines.

  4. Analysis of TJ-II experimental data with neoclassical formulations of the radial electric field

    NASA Astrophysics Data System (ADS)

    Gutiérrez-Tapia, C.; Martinell, J. J.; López-Bruna, D.; Melnikov, A. V.; Eliseev, L.; Rodríguez, C.; Ochando, M. A.; Castejón, F.; García, J.; van Milligen, B. P.; Fontdecaba, J. M.

    2015-11-01

    Neoclassical theory provides usable expressions for studying transport in toroidal plasmas and computing the associated radial electric field. An algebraic and three semi-analytical models are used here to study the radial electric field in TJ-II plasmas and compare it with experimental data from a heavy ion beam probe (HIBP) and with DKES calculations. Good qualitative agreement as well as reasonable quantitative agreement is found which allows us to validate the models for describing TJ-II radial electric fields. Furthermore, a simple algebraic formulation (2005 Plasma Phys. Rep. 31 14) provides physical insight for the interpretation of experimental data from the TJ-II heliac in spite of its complicated geometry, like the place of the transition from the electron to the ion root of the radial electric field, which occurs at the maximum value of collisionality, for example.

  5. Crystal structure of hexa­kis­(di­methyl­formamide-κO)manganese(II) deca­kis­(di­methyl­formamide)-1κ5 O,2κ5 O-[μ-octa­deca­tungstodiphosphato(V)-κO:κO′]dimanganate(II) di­methyl­formamide disolvate

    PubMed Central

    Dhifallah, Fatma; Belkhiria, Mohamed Salah

    2016-01-01

    The crystal structure of the title compound, [Mn(C3H7NO)6][{Mn(C3H7NO)5}2(μ-P2W18O62)]·2C3H7NO, reveals that the Wells–Dawson-type polyanion [P2W18O62]6−, through terminal O atoms from the belts, bridges two MnII octa­hedral complexes. In the complex anion [{Mn(dmf)5}2(μ-P2W18O62)]2−, located around a twofold rotation axis, the MnII ions are coordinated by five O atoms from di­methyl­formamide (dmf) ligands and to a terminal O atom from the [P2W18O62]6− polyanion. Another MnII ion, located on an inversion centre, is coordinated by six O atoms from the dmf ligands and forms the [Mn(dmf)6]2+ cation. The crystal components are connected through numerous weak C—H⋯O hydrogen bonds to construct a three-dimensional network. PMID:27308055

  6. The histone methyltransferase KMT2B is required for RNA polymerase II association and protection from DNA methylation at the MagohB CpG island promoter.

    PubMed

    Ladopoulos, Vasileios; Hofemeister, Helmut; Hoogenkamp, Maarten; Riggs, Arthur D; Stewart, A Francis; Bonifer, Constanze

    2013-04-01

    KMT2B (MLL2/WBP7) is a member of the MLL subfamily of H3K4-specific histone lysine methyltransferases (KMT2) and is vital for normal embryonic development in the mouse. To gain insight into the molecular mechanism underlying KMT2B function, we focused on MagohB, which is controlled by a CpG island promoter. We show that in cells lacking Mll2-the gene encoding KMT2B-the MagohB promoter resides in inaccessible chromatin and is methylated. To dissect the molecular events leading to the establishment of silencing, we performed kinetic studies in Mll2-conditional-knockout embryonic stem cells. KMT2B depletion was followed by the loss of the active chromatin marks and progressive loss of RNA polymerase II binding with a concomitant downregulation of MagohB expression. Once the active chromatin marks were lost, the MagohB promoter was rapidly methylated. We demonstrate that in the presence of KMT2B, neither transcription elongation nor RNA polymerase II binding is required to maintain H3K4 trimethylation at the MagohB promoter and protect it from DNA methylation. Reexpression of KMT2B was sufficient to reinstate an active MagohB promoter. Our study provides a paradigm for the idea that KMT2 proteins are crucial components for establishing and maintaining the transcriptionally active and unmethylated state of CpG island promoters. PMID:23358417

  7. Bis{μ-2-meth-oxy-6-[(methyl-imino)-meth-yl]phenolato}bis-({2-meth-oxy-6-[(methyl-imino)-meth-yl]phenolato}copper(II)).

    PubMed

    Sydoruk, Tetyana V; Buvaylo, Elena A; Kokozay, Vladimir N; Vassilyeva, Olga Yu; Skelton, Brian W

    2013-01-01

    The title compound, [Cu2(C9H10NO2)4], is built of discrete centrosymmetric dimers. The Cu(II) atoms are each five coordinated by two deprotonated Schiff base ligands that are bonded differently to the metal atoms. Of the two phenolate O atoms, one is coordinated to one Cu(II) atom, whereas another bridges the two metal atoms. The basal plane of the square pyramid around Cu(II) atoms is formed by the imino N and phenolate O atoms of the bidentate and the monodentate/bidentate Schiff base ligands. The bridging phenolate oxygen occupies the apical position of the coordination sphere with a considerably longer Cu-O bond length. In the crystal, the dimeric mol-ecules pack relative to each other in such a way that the Cu2O2 planes of adjacent dimers are orthogonal. PMID:24098180

  8. Experimental, DFT and molecular docking studies on 2-(2-mercaptophenylimino)-4-methyl-2H-chromen-7-ol

    NASA Astrophysics Data System (ADS)

    Singh, Ashok Kumar; Singh, Ravindra Kumar

    2016-10-01

    A new coumarin derivative 2-(2-mercaptophenylimino)-4-methyl-2H-chromen-7-ol (COMSB) was synthesized and characterized with the help of 1H,13C NMR, FT-IR, FT-Raman and mass spectrometry. All quantum calculations were performed at DFT level of theory using B3LYP functional and 6-31G (d,p) as basis set. The UV-Vis spectrum studied by TD-DFT theory, with a hybrid exchange-correlation functional using Coulomb-attenuating method (CAM-B3LYP) in solvent phase gives similar pattern of bands, at energies and is consistent with that of experimental findings. The detailed analysis of vibrational (IR and Raman) spectra and their assignments has been done by computing Potential Energy Distribution (PED) using Gar2ped. Intra-molecular interactions were analyzed by 'Atoms in molecule' (AIM) approach. Computed first static hyperpolarizability (β0 = 8.583 × 10-30 esu) indicates non-linear optical (NLO) response of the molecule. Molecular docking studies show that the title molecule may act as potential acetylcholine esterase (AChE) inhibitor.

  9. A DFT/TD DFT study of the structure and spectroscopic properties of 5-methyl-2-(8-quinolinyl)benzoxazole and its complexes with Zn(II) ion.

    PubMed

    Guzow, Katarzyna; Milewska, Magda; Czaplewski, Cezary; Wiczk, Wiesław

    2010-02-01

    The structure and spectroscopic properties of 5-methyl-2-(8-quinolinyl)benzoxazole and its complexes with Zn(II) ion were studied using a DFT and TD DFT methods with def2-TZVP basis set. It was shown that the type of functional used (B3-LYP or pbe0) implemented in TURBOMOLE package does not have essential influence on the geometry (small differences in bond length, valence and dihedral angles) of studied compounds in both ground and excited states. However, significant differences were obtained for the position of vertical absorption and emission transition but not for the oscillator strength of transition. Application of pbe0 functional seems to reproduce better the experimental spectrum.

  10. Structure of a fluid dioleoylphosphatidylcholine bilayer determined by joint refinement of x-ray and neutron diffraction data. II. Distribution and packing of terminal methyl groups.

    PubMed Central

    Wiener, M C; White, S H

    1992-01-01

    We continue in this paper the presentation of theoretical and experimental methods for the joint refinement of neutron and x-ray lamellar diffraction data for the analysis of fluid (L alpha phase) bilayer structure (Wiener, M. C., and S. H. White. 1991 a, b, c. Biophys. J. 59:162-173 and 174-185; Biochemistry. 30:6997-7008; Wiener, M. C., G. I. King, and S. H. White. Biophys. J. 60: 568-576). We show how to obtain the distribution and packing of the terminal methyls in the interior of a fluid dioleoylphosphatidylcholine bilayer (66% RH) by combining x-ray and neutron scattering-length transbilayer profiles with no a priori assumptions about the functional form of the distribution. We find that the methyls can be represented by a Gaussian function with 1/e-halfwidth of 2.95 +/- 0.28 A situated at the bilayer center. There is substantial mixing of the methyls and methylenes in the bilayer center. The Gaussian representation of the methyl distribution is narrower and has a different shape than predicted by several simulations of fluid bilayers (Gruen, D. W. R., and E. H. B. de Lacey. 1984. Surfactants in Solution, Vol. 1. Plenum Publishing Corp., New York. 279-306; de Loof, H., et al. 1991. Biochemistry. 30:2099-2133) but this may be due to the smaller area/lipid of our experiments and the presence of the double-bonds. Determination of the absolute specific volume of DOPC and an analysis of bulk alkane volumetric data over a range of hydrostatic pressures lead to estimates of methylene and methyl volumes at the bilayer center of 27 +/- 1 A3 and 57.2 +/- 3.6 A3, respectively. This result provides direct confirmation of the common assumption that the molecular packing of methyl and methylene groups in bilayers is the same as in bulk liquid alkanes. Images FIGURE 2 PMID:1547330

  11. Inorganic and organic structures as interleavers among [bis(1-methyl-3-(p-carboxylatephenyl)triazenide 1-oxide)Ni(II)] complexes to form supramolecular arrangements

    NASA Astrophysics Data System (ADS)

    Santos, Aline Joana Rolina Wohlmuth Alves; dos Santos Hackbart, Helen Cristina; Giacomini, Gabriela Xavier; Bersch, Patrícia; Paraginski, Gustavo Luiz; Hörner, Manfredo

    2016-12-01

    Alternative compounds to capture metal ions are triazenes 1-oxide since they are basic compounds O(N) with negative charge in the deprotonated form. The proximity of both coordination sites (O and N) enables these compounds to have good chelating ability and a tendency to stabilize in the formation of rings with soft and hard transition metal ions. The structure analysis by single crystal X-ray diffraction of compounds (1) and (2) demonstrate the formation of 3D supramolecular arrangements through ion-ion, ion-dipolo and dipolo-dipolo interactions. In one of them, there are [(H2O)2(CH3CH3SO)K2]2+ as linkers of polymerization and, in another complex, there are [(H2O)(CH3CH3SO)Ni(H2O)6]2+ as a linker of polymerization. These linkers act in the polymerization of the novel mononuclear complex [bis(1-methyl (p-carboxylatephenyl) triazenide 1-oxide) NiII] (3). The crystallography analysis of (1) and (2) showed distorted quadratic geometry for Ni (II), thus, there are two axial positions available in Ni (II) to be used in catalysis studies and as sensor or biosensor. In addition, this study shows the support of this novel mononuclear complex of Ni (II) (3) on protonated chitosan chains (4). The compounds (3) and (4) were characterized by spectroscopic analysis, infrared (IR) and energy dispersive X-ray detector (EDS), and by differential scanning calorimetry analysis (DSC). The specificity of ligand 1-methyl (p-carboxyphenyl) triazene 1-oxide to capture potassium and nickel ions will be tested at different pH values, as well as the capacity of the triazenide 1-oxide of Ni (II) complex, supported on chitosan polymer, or not, to act as a catalyst for organic reactions and biomimetic organic reactions.

  12. Low-order dynamic modeling of the Experimental Breeder Reactor II

    SciTech Connect

    Berkan, R.C. . Dept. of Nuclear Engineering); Upadhyaya, B.R.; Kisner, R.A. )

    1990-07-01

    This report describes the development of a low-order, linear model of the Experimental Breeder Reactor II (EBR-II), including the primary system, intermediate heat exchanger, and steam generator subsystems. The linear model is developed to represent full-power steady state dynamics for low-level perturbations. Transient simulations are performed using model building and simulation capabilities of the computer software Matrix{sub x}. The inherently safe characteristics of the EBR-II are verified through the simulation studies. The results presented in this report also indicate an agreement between the linear model and the actual dynamics of the plant for several transients. Such models play a major role in the learning and in the improvement of nuclear reactor dynamics for control and signal validation studies. This research and development is sponsored by the Advanced Controls Program in the Instrumentation and Controls Division of the Oak Ridge National Laboratory. 17 refs., 67 figs., 15 tabs.

  13. Novel Cobalt(II) complexes containing N,N-di(2-picolyl)amine based ligands; Synthesis, characterization and application towards methyl methacrylate polymerisation

    NASA Astrophysics Data System (ADS)

    Ahn, Seoung Hyun; Choi, Sang-Il; Jung, Maeng Joon; Nayab, Saira; Lee, Hyosun

    2016-06-01

    The reaction of [CoCl2·6H2O] with N‧-substituted N,N-di(2-picolyl)amine ligands such as 1-cyclohexyl-N,N-bis(pyridin-2-ylmethyl)methanamine (LA), 2-methoxy-N,N-bis(pyridin-2-ylmethyl)ethan-1-amine (LB), and 3-methoxy-N,N-bis(pyridin-2-ylmethyl)propan-1-amine (LC), yielded [LnCoCl2] (Ln = LA, LB and LC), respectively. The Co(II) centre in [LnCoCl2] (Ln = LA, and LC) adopted distorted bipyramidal geometries through coordination of nitrogen atoms of di(2-picolyl)amine moiety to the Co(II) centre along with two chloro ligands. The 6-coordinated [LBCoCl2] showed a distorted octahedral geometry, achieved through coordination of the two pyridyl units, two chloro units, and bidentate coordination of nitrogen and oxygen in the N‧-methoxyethylamine to the Co(II) centre. [LCCoCl2] (6.70 × 104 gPMMA/molCo h) exhibited higher catalytic activity for the polymerisation of methyl methacrylate (MMA) in the presence of modified methylaluminoxane (MMAO) compared to rest of Co(II) complexes. The catalytic activity was considered as a function of steric properties of ligand architecture and increased steric bulk around the metal centre resulted in the decrease catalytic activity. All Co(II) initiators yielded syndiotactic poly(methylmethacrylate) (PMMA).

  14. Tetra methyl substituted Cu(II) phthalocyanine as alternative hole transporting material for organometal halide perovskite solar cells

    NASA Astrophysics Data System (ADS)

    Sfyri, Georgia; Kumar, Challuri Vijay; Wang, Yu-Long; Xu, Zong-Xiang; Krontiras, C. A.; Lianos, Panagiotis

    2016-01-01

    Copper phthalocyanine is a promising hole transporting material, which can be employed with solid state perovskite solar cells. Tetra methyl substituted copper phthalocyanine was presently studied as a hole transporting material and demonstrated improved performance with respect to unsubstituted copper phthalocyanine. This material shows a strong absorption in the Visible and Near IR part of the electromagnetic spectrum contributing to the absorption of photons. Its LUMO and HOMO level are favourably positioned for injecting electrons and scavenging holes. Methyl substitution facilitates closer molecular packing leading to a stronger extinction coefficient, stronger π-π interaction and higher charge carrier mobility.

  15. Experimental Determination of Densities and Isobaric Vapor-Liquid Equilibria of Methyl Acetate and Ethyl Acetate with Alcohols (C3 and C4) at 0.3 MPa

    NASA Astrophysics Data System (ADS)

    Susial, Pedro; Estupiñan, Esteban J.; Castillo, Victor D.; Rodríguez-Henríquez, José J.; Apolinario, José C.

    2013-10-01

    The densities and excess volumes were determined at 298.15 K for the methyl acetate + 1-propanol, methyl acetate + 1-butanol, and ethyl acetate + 1-butanol mixtures. The vapor-liquid equilibria data at 0.3 MPa for these binary systems were obtained using a stainless steel equilibrium still. The activity coefficients were obtained from the experimental data using the Hayden and O’Connell method and the Yen and Woods equation. The binary systems in this study showed positive deviations from ideality. The experimental VLE data were verified with the point-to-point test of van Ness using the Barker routine and the Fredenslund criterion. The different versions of the UNIFAC and the ASOG group contribution models were applied.

  16. {(1R,2R,4R)-4-Methyl-1,2-cyclohexanediamine}oxalatoplatinum(II): A Novel Enantiomerically Pure Oxaliplatin Derivative Showing Improved Anticancer Activity in Vivo

    PubMed Central

    Abramkin, Sergey A.; Jungwirth, Ute; Valiahdi, Seied M.; Dworak, Claudia; Habala, Ladislav; Meelich, Kristof; Berger, Walter; Jakupec, Michael A.; Hartinger, Christian G.; Nazarov, Alexey A.; Galanski, Markus; Keppler, Bernhard K.

    2012-01-01

    Novel derivatives of the clinically established anticancer drug oxaliplatin were synthesized. Cytotoxicity of the compounds was studied in six human cancer cell lines by means of the MTT assay. Additionally, most promising complexes were also investigated in cisplatin- and oxaliplatin-resistant human cancer cell models. The therapeutic efficacy in vivo was studied in the murine L1210 leukemia model. Most remarkably, {(1R,2R,4R)-4-methyl-1,2-cyclohexanediamine}oxalatoplatinum(II), comprising an equatorial methyl substituent at position 4 of the cyclohexane ring, was as potent as oxaliplatin in vitro but distinctly more effective in the L1210 model in vivo at the optimal dose. The advantage observed in the in vivo situation was mainly based on a more favorable therapeutic index. The maximum tolerated dose of the novel analogue was higher than that of oxaliplatin and caused a greater increase in life span (>200% versus 152%), with more animals experiencing long-term survival (5/6 versus 2/6). These data support further (pre)clinical development of the methyl-substituted oxaliplatin analogue with improved anticancer activity. PMID:20886814

  17. Disentangling steric and electronic factors in monomeric bis(2-bromo-4-chloro-6-{[(2-hydroxyethyl)imino]methyl}phenolato-κ(2)N,O)copper(II).

    PubMed

    Zabierowski, Piotr; Szklarzewicz, Janusz; Nitek, Wojciech

    2014-07-01

    The title compound, [Cu(C9H8BrClNO2)2], is a square-planar complex. The potentially tridentate dibasic 2-bromo-4-chloro-6-{[(2-hydroxyethyl)imino]methyl}phenolate ligand coordinates in a trans-bis fashion to the Cu(II) centre via the imine N and phenolate O atoms. The Cu(II) atom lies on the centre of inversion of the molecule. The potentially coordinating hydroxyethyl group remains protonated and uncoordinated, taking part in intermolecular hydrogen bonds with vicinal groups, leading to the formation of a two-dimensional hydrogen-bond network with sheets parallel to the (101) plane. Substituent effects on the crystal packing and coordination modes of the ligand are discussed.

  18. Synthesis and spectroscopic studies of 4-phenylacetyl-3-methyl-1-phenylpyrazolone-5 and its thorium(VI), lanthanum(III) and lead(II) complexes

    NASA Astrophysics Data System (ADS)

    Uzoukwu, Bieluonwu Augustus; Adiukwu, Patricia Ugboaku

    1995-12-01

    The synthesis of 4-phenylacetyl-3-methyl-1-phenylpyrazolone-5 is reported. Analysis of its IR and NMR spectral data has revealed that the ligand is bidentate and has spectral properties that resemble neither those of the 4-benzoyl, 4-acetyl derivatives nor those of the trihaloacetyl derivatives which have p Ka values < 4.0. Instead the spectral properties are similar to those of the 4-alkanoyl derivatives which have p Ka values . 4.0. The thorium(VI), lanthanum(III) and lead(II) complexes were isolated and characterized by UV, IR and 1H, 13C NMR spectral studies. The complexes were anhydrous and conform to a general molecular formula ML n where M( n) is Th(VI), La(III), Pb(II).

  19. catena-Poly[[bis­(4-methyl­benzene­thiol­ato)cadium(II)]-μ-1,3-di-4-pyridylpropane

    PubMed Central

    Zhang, Yan; Zhou, Yan; Han, Lei

    2009-01-01

    In the title compound, [Cd(C7H7S)2(C13H14N2)]n, the unique CdII ion, located on a twofold rotation axis, is coordinated by two S atoms and two N atoms in a slightly distorted tetra­hedral environment. Symmetry-related CdII ions are linked via bridging 1,3-di-4-pyridylpropane ligands, forming a zig-zag chain-structure parallel to [001]. In the crystal structure, there are weak intra­chain π–π stacking inter­actions between benzene rings, with a centroid–centroid distance of 3.825 (7) Å, and pairs of chains are inter­digitated with respect to the 4-methyl­benzene­thiol­ate groups. PMID:21582384

  20. Chloro({2-[mesityl(quinolin-8-yl-κN)boryl]-3,5-dimethyl-phenyl}methyl-κC)palladium(II) as a catalyst for Heck reactions.

    PubMed

    Tamang, Sem Raj; Hoefelmeyer, James D

    2015-01-01

    We recently reported an air and moisture stable 16-electron borapalladacycle formed upon combination of 8-quinolyldimesitylborane with bis(benzonitrile)dichloropalladium(II). The complex features a tucked mesityl group formed upon metalation of an ortho-methyl group on a mesityl; however it is unusually stable due to contribution of the boron pz orbital in delocalizing the carbanion that gives rise to an η4-boratabutadiene fragment coordinated to Pd(II), as evidenced from crystallographic data. This complex was observed to be a highly active catalyst for the Heck reaction. Data of the catalyst activity are presented alongside data found in the literature, and initial comparison reveals that the borapalladacycle is quite active. The observed catalysis suggests the borapalladacycle readily undergoes reductive elimination; however the Pd(0) complex has not yet been isolated. Nevertheless, the ambiphilic ligand 8-quinolyldimesitylborane may be able to support palladium in different redox states. PMID:26193250

  1. The FERRUM Project: Experimental Transition Probabilities of [Fe II] and Astrophysical Applications

    NASA Technical Reports Server (NTRS)

    Hartman, H.; Derkatch, A.; Donnelly, M. P.; Gull, T.; Hibbert, A.; Johannsson, S.; Lundberg, H.; Mannervik, S.; Norlin, L. -O.; Rostohar, D.

    2002-01-01

    We report on experimental transition probabilities for thirteen forbidden [Fe II] lines originating from three different metastable Fe II levels. Radiative lifetimes have been measured of two metastable states by applying a laser probing technique on a stored ion beam. Branching ratios for the radiative decay channels, i.e. M1 and E2 transitions, are derived from observed intensity ratios of forbidden lines in astrophysical spectra and compared with theoretical data. The lifetimes and branching ratios are combined to derive absolute transition probabilities, A-values. We present the first experimental lifetime values for the two Fe II levels a(sup 4)G(sub 9/2) and b(sup 2)H(sub 11/2) and A-values for 13 forbidden transitions from a(sup 6)S(sub 5/2), a(sup 4)G(sub 9/2) and b(sup 4)D(sub 7/2) in the optical region. A discrepancy between the measured and calculated values of the lifetime for the b(sup 2)H(sub 11/2) level is discussed in terms of level mixing. We have used the code CIV3 to calculate transition probabilities of the a(sup 6)D-a(sup 6)S transitions. We have also studied observational branching ratios for lines from 5 other metastable Fe II levels and compared them to calculated values. A consistency in the deviation between calibrated observational intensity ratios and theoretical branching ratios for lines in a wider wavelength region supports the use of [Fe II] lines for determination of reddening.

  2. Synthesis, photophysical and electrochemical properties of a mixed bipyridyl-phenanthrolyl ligand Ru(II) heteroleptic complex having trans-2-methyl-2-butenoic acid functionalities.

    PubMed

    Adeloye, Adewale O

    2011-01-01

    In this work, two ligands: 4-(trans-2-Methyl-2-butenoic acid)-2,2'-bipyridine) (L(1)) and 5-(trans-2-methyl-2-butenoic acid)-1,10-phenanthroline (L(2)), with the corresponding mixed-ligand heteroleptic Ru(II) complex were synthesized and characterized by FT-IR, 1H-, 13C-NMR spectroscopy and elemental analysis. The influence of the mixed functionalized polypyridyl ruthenium(II) complex on the photophysical and electrochemical properties were investigated and compared to individual single-ligand homoleptic complexes. Interestingly, the mixed-ligand complex formulated as [RuL(1)L(2)(NCS)(2)] exhibits broad and intense metal-to-ligand charge transfer (MLCT) absorption with a high molar extinction coefficient (λ(max) = 514 nm, ε = 69,700 M(-1) cm(-1)), better than those of individual single-ligand complexes, [Ru(L(1))(2)(NCS)(2)] and [Ru(L(2))(2)(NCS)(2)], and a strong photoluminescence intensity ratio in the red region at λ(em) = 686 nm. The electrochemical properties of the complex indicated that the redox processes are ligand-based.

  3. Biological activities of Zn(II)-S-methyl-cysteine complex as antiradical, inhibitor of acid phosphatase enzyme and in vivo antidepressant effects.

    PubMed

    Escudero, Graciela E; Martini, Nancy; Jori, Khalil; Jori, Nadir; Maresca, Nahuel R; Laino, Carlos H; Naso, Luciana G; Williams, Patricia A M; Ferrer, Evelina G

    2016-12-01

    The antidepressant effect of simple Zn(II) salts has been proved in several animal models of depression. In this study, a coordination metal complex of Zn(II) having a sulfur containing ligand is tested as antidepressant for the first time. Forced swimming test method on male Wistar rats shows a decrease in the immobility and an increase in the swimming behavior after treatment with [Zn(S-Met)2] (S-Met=S-methyl-l-cysteine) being more effective and remarkable than ZnCl2. The thiobarbituric acid and the pyranine consumption (hydroxyl and peroxyl radicals, respectively) methods were applied to evaluate the antioxidant activity of S-Met and [Zn(S-Met)2] showing evidence of attenuation of hydroxyl but not peroxyl radicals activities. UV-vis studies on the inhibition of acid phosphatase enzyme (AcP) demonstrated that S-methyl-l-cysteine did not produce any effect but, in contrast, [Zn(S-Met)2] complex behaved as a moderate inhibitor. Finally, bioavailability studies were performed by fluorescence spectroscopy denoting the ability of the albumin to transport the complex.

  4. Mononuclear zinc(II) complexes of 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols: Synthesis, structural characterization, DNA binding and cheminuclease activities

    NASA Astrophysics Data System (ADS)

    Ravichandran, J.; Gurumoorthy, P.; Karthick, C.; Kalilur Rahiman, A.

    2014-03-01

    Four new zinc(II) complexes [Zn(HL1-4)Cl2] (1-4), where HL1-4 = 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols, have been isolated and fully characterized using various spectro-analytical techniques. The X-ray crystal structure of complex 4 shows the distorted trigonal-bipyramidal coordination geometry around zinc(II) ion. The crystal packing is stabilized by intermolecular NH⋯O hydrogen bonding interaction. The complexes display no d-d electronic band in the visible region due to d10 electronic configuration of zinc(II) ion. The electrochemical properties of the synthesized ligands and their complexes exhibit similar voltammogram at reduction potential due to electrochemically innocent Zn(II) ion, which evidenced that the electron transfer is due to the nature of the ligand. Binding interaction of complexes with calf thymus DNA was studied by UV-Vis absorption titration, viscometric titration and cyclic voltammetry. All complexes bind with CT DNA by intercalation, giving the binding affinity in the order of 2 > 1 ≫ 3 > 4. The prominent cheminuclease activity of complexes on plasmid DNA (pBR322 DNA) was observed in the absence and presence of H2O2. Oxidative pathway reveals that the underlying mechanism involves hydroxyl radical.

  5. Hyperfine-structure studies of Nb ii: Experimental and relativistic configuration-interaction results

    NASA Astrophysics Data System (ADS)

    Young, L.; Hasegawa, S.; Kurtz, C.; Datta, Debasis; Beck, Donald R.

    1995-05-01

    We report an experimental and theoretical study of the hyperfine structure (hfs) in various metastable states in 93Nb ii. Hyperfine structures of five levels in Nb ii have been measured using a combination of the laser-rf double resonance and laser-induced fluorescence methods in a collinear laser-ion-beam geometry. Theoretically, for J=2, a multireference calculation of energies and hfs based on a relativistic configuration-interaction methodology of the lowest ten levels in the (4d+5s)4 manifold is reported. The average energy error is 450 cm-1. Many of the hyperfine constants show large changes from the Dirac-Fock values and the magnetic dipole constant has a 4% accuracy for the one J=2 level measured. We have also identified all the core-valence and core-core effects that dominate the energy differences and hfs.

  6. Development and comparison of a TOPAZ-II system model with experimental data

    SciTech Connect

    Paramonov, D.V.; El-Genk, M.S. . Inst. for Space Nuclear Power Studies)

    1994-11-01

    An integrated model of the TOPAZ-II space nuclear reactor system is developed and compared with measurements from the TOPAZ-II, V-71 unit tests. For a given reactor thermal power, the model calculates the coolant flow rate, temperature, and pressure throughout the system; load electric power; and overall system efficiency. Model predictions showed good agreement with the experimental data. The calculated coolant temperatures and pressure are within 15 K (< 2%) and 12% of the measurements, respectively. Analysis showed that at the nominal operating thermal power of the system (115 kW), and NaK coolant is highly subcooled. The largest subcooling of 365 K occurs at the exit of the electromagnetic pump, where coolant pressure is highest, and the lowest subcooling of 275 K occurs at the exit of the reactor core, where coolant temperature is highest.

  7. Crystal structure of a dinuclear Co(II) complex with bridging fluoride ligands: di-μ-fluorido-bis-{tris-[(6-methyl-pyridin-2-yl)meth-yl]amine}-dicobalt(II) bis-(tetra-fluorido-borate).

    PubMed

    Inomata, Masataka; Suenaga, Yusaku

    2014-11-01

    Reaction of Co(BF4)2·6H2O with tris-[(6-methyl-pyridin-2-yl)meth-yl]amiine in methanol results in a fluoride abstraction from BF4 (-), yielding the unexpected title compound, [Co2F2(C21H24N4)2](BF4)2. The complex cation consists of two inversion-related [Co(C21H24N4)](2+) moieties bridged by a pair of fluoride ligands. The Co(II) cation is six-coordinated in a distorted octa-hedral geometry and forms a +II high-spin state. In the crystal, the complex cation and the BF4 (-) anion are connected by C-H⋯F hydrogen bonds, forming a three-dimensional network. An intra-molecular C-H⋯F hydrogen bond is also observed. PMID:25484774

  8. Experimental challenge to nucleosynthesis in core-collapse supernovae - Very early epoch of type II SNe -

    NASA Astrophysics Data System (ADS)

    Kubono, S.; Binh, Dam N.; Hayakawa, S.; Hashimoto, T.; Kahl, D. M.; Yamaguchi, H.; Wakabayashi, Y.; Teranishi, T.; Iwasa, N.; Komatsubara, T.; Kato, S.; Chen, A.; Cherubini, S.; Choi, S. H.; Hahn, I. S.; He, J. J.; Khiem, Le H.; Lee, C. S.; Kwon, Y. K.; Wanajo, S.; Janka, H.-T.

    2013-05-01

    Nucleosynthesis is one of the keys in studying the mechanism of core-collapse supernovae, which is an interesting challenge for modern science. The νp-process, which is similar to an explosive hydrogen burning process, has been proposed as the most probable process in the very early epoch of type II supernovae. Here, we discuss our experimental efforts for the νp-process, the first extensive direct measurements of the (α,p) reactions on bottle-neck proto-rich nuclei in light mass regions. Other challenges for the νp-process study are also discussed.

  9. Methyl iodide oxidative addition to [Rh(acac)(CO)(PPh3)]: an experimental and theoretical study of the stereochemistry of the products and the reaction mechanism.

    PubMed

    Conradie, Marrigje M; Conradie, Jeanet

    2011-08-28

    Density functional theory was used to investigate the oxidative addition and subsequent carbonyl insertion and deinsertion steps of the reaction of methyl iodide to a rhodium(I) acetylacetonato complex of the formula [Rh(acac)(CO)(PPh(3))] (Hacac = acetylacetone). This process has been studied experimentally for many rhodium β-diketonato complexes, but, to the best of our knowledge, this is the first systematic computational study of the complete reaction sequence. Experimental (1)H techniques complement the theoretical results on the stereochemistry of the reaction intermediates and products. (1)H NMR also revealed the existence of a second rhodium(III)-acyl product, which has not been previously observed in this reaction. The calculated Gibbs free energy of activation of the oxidative addition reaction is 71 kJ mol(-1), which is in agreement with the experimental value of 82(1) kJ mol(-1). The DFT-calculated oxidative addition corresponds to an associative S(N)2 nucleophilic attack by the rhodium metal centre on the methyl iodide, which is in agreement with calculated and experimental (in brackets) activation parameters of the reaction, 27 (38.8) kJ mol(-1) for ΔH((≠)) and -147 (-146) J K(-1) mol(-1) for ΔS((≠)). PMID:21761056

  10. Theoretical and experimental studies of stressed nanoparticles of II-VI semiconductors.

    PubMed

    Ferreira, D Lourençoni; Silva, F Oliveira; Viol, L Cristina de Souza; Licínio, P; Schiavon, M Antônio; Alves, J Luiz Aarestrup

    2010-01-01

    A theoretical and experimental study of isolated nanoparticles of II-VI semiconductor materials has been done. Using the framework of the effective mass model, the optical absorption spectrum of distributions of spherical quantum dots, freestanding, and under compressive or tensile stress, has been examined theoretically. The theoretical results allow one to foresee the absorption spectra of quantum dots made of a series of materials and having any size. The syntheses of colloidal quantum dots of CdS and CdSe has also been performed through wet chemical routes and characterized by means of optical techniques. The values of the strains in the synthesized quantum dots were inferred from a correlation established between the theoretical and the experimental results. PMID:20078149

  11. Antioxidant, DNA binding and nuclease activities of heteroleptic copper(II) complexes derived from 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols and diimines

    NASA Astrophysics Data System (ADS)

    Ravichandran, J.; Gurumoorthy, P.; Imran Musthafa, M. A.; Kalilur Rahiman, A.

    2014-12-01

    A series of heteroleptic copper(II) complexes of the type [CuL1-4(diimine)](ClO4)2 (1-8) [L1-4 = 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols, and diimine = 2,2‧-bipyridyl (bpy) or 1,10-phenanthroline (phen)], have been synthesized and characterized by spectroscopic methods. The IR spectra of complexes indicate the presence of uncoordinated perchlorate anions and the electronic spectra revealed the square pyramidal geometry with N4O coordination environment around copper(II) nuclei. Electrochemical studies of the mononuclear complexes evidenced one-electron irreversible reduction wave in the cathodic region. The EPR spectra of complexes with g|| (2.206-2.214) and A|| (154-172 × 10-4 cm-1) values support the square-based CuN3O coordination chromophore and the presence of unpaired electron localized in dx-y ground state. Antioxidant studies against DPPH revealed effective radical scavenging properties of the synthesized complexes. Binding studies suggest that the heteroleptic copper(II) complexes interact with calf thymus DNA (CT-DNA) through minor-groove and electrostatic interaction, and all the complexes display pronounced nuclease activity against supercoiled pBR322 DNA.

  12. Solvent extraction of N-Cyclohexyl-N-Nitrosohydroxylamine (cnha) into some organic solvents and of the Cu(II)-cnha complex into methyl isobutyl ketone.

    PubMed

    Rauret, G; Pineda, L; Ventura, M; Compaño, R

    1986-02-01

    The distribution equilibria of N-cyclohexyl-N-nitrosohydroxylamine (cnha) in the water-chloroform, water-hexane, water-methyl isobutyl ketone (MIBK) and water-isopentyl alcohol systems, and of the Cu(II)-cnha complex in the water-MIBK system have been studied. From the distribution data the dissociation and distribution constants of the reagent have been calculated; their values are pK(a) = 5.55 +/- 0.10; log K(DR) = 2.46 +/- 0.05 (chloroform), 1.76 +/- 0.11 (MIBK), 1.06 +/- 0.07 (hexane) and 1.48 +/- 0.06 (isopentyl alcohol). In the same way the values of the distribution and stability constants of the Cu(II) complex have been obtained; log K(DC) = 3.51; log beta(1) = 7.23 +/- 0.10 and log beta(2) = 12.00 +/- 0.08. For the determination of cnha in the aqueous phase saturated with MIBK, a spectrophotometric method based on the coloured complex formed by the reagent with Fe(III) has been established. Finally, an analytical method for Cu(II) by atomic-absorption spectrometry after its extraction with cnha into MIBK, is proposed. Its detection limit is 4.6 mug l ., its precision +/- 2.1% and its accuracy 97.5%. This method has been applied to the determination of the copper content in the surface water of the Congest River of Catalonia (Spain). PMID:18964050

  13. Chemical constituents of Malagasy liverworts, part II: mastigophoric acid methyl ester of biogenetic interest from Mastigophora diclados (Lepicoleaceae Subf. Mastigophoroideae).

    PubMed

    Harinantenaina, Liva; Asakawa, Yoshinori

    2004-11-01

    In the course of our chemotaxonomic study of the liverworts growing in Madagascar, mastigophoric acid methyl ester, along with eleven known compounds were isolated from Mastigophora diclados. Isolated metabolites showed that the Malagasy Mastigophora is more related to the samples from Borneo and Japan than to the Taiwanese or Malaysian ones. The biosynthesis of the herbertane type sesquiterpenoids from Mastigophora diclados is suggested to be similar to those found in the genus Herbertus. The herbertane-type sesquiterpenoids were screened for Staphylococcus aureus strain inhibition.

  14. Liquid metal reactor deactivation as applied to the experimental breeder reactor - II.

    SciTech Connect

    Earle, O. K.; Michelbacher, J. A.; Pfannenstiel, D. F.; Wells, P. B.

    1999-05-28

    The Experimental Breeder Reactor-II (EBR-II) at Argonne National Laboratory-West (ANL-W) was shutdown in September, 1994. This sodium cooled reactor had been in service since 1964, and by the US Department of Energy (DOE) mandate, was to be placed in an industrially and radiologically safe condition for ultimate decommissioning. The deactivation of a liquid metal reactor presents unique concerns. The first major task associated with the project was the removal of all fueled assemblies. In addition, sodium must be drained from systems and processed for ultimate disposal. Residual quantities of sodium remaining in systems must be deactivated or inerted to preclude future hazards associated with pyrophoricity and generation of potentially explosive hydrogen gas. A Sodium Process Facility (SPF) was designed and constructed to react the elemental sodium from the EBR-II primary and secondary systems to sodium hydroxide for disposal. This facility has a design capacity to allow the reaction of the complete inventory of sodium at ANL-W in less than two years. Additional quantities of sodium from the Fermi-1 reactor are also being treated at the SPF.

  15. Alveolar Type II Epithelial Cell Dysfunction in Rat Experimental Hepatopulmonary Syndrome (HPS)

    PubMed Central

    Yang, Wenli; Hu, Bingqian; Wu, Wei; Batra, Sachin; Blackburn, Michael R.; Alcorn, Joseph L.; Fallon, Michael B.; Zhang, Junlan

    2014-01-01

    The hepatopulmonary syndrome (HPS) develops when pulmonary vasodilatation leads to abnormal gas exchange. However, in human HPS, restrictive ventilatory defects are also observed supporting that the alveolar epithelial compartment may also be affected. Alveolar type II epithelial cells (AT2) play a critical role in maintaining the alveolar compartment by producing four surfactant proteins (SPs, SP-A, SP-B, SP-C and SP-D) which also facilitate alveolar repair following injury. However, no studies have evaluated the alveolar epithelial compartment in experimental HPS. In this study, we evaluated the alveolar epithelial compartment and particularly AT2 cells in experimental HPS induced by common bile duct ligation (CBDL). We found a significant reduction in pulmonary SP production associated with increased apoptosis in AT2 cells after CBDL relative to controls. Lung morphology showed decreased mean alveolar chord length and lung volumes in CBDL animals that were not seen in control models supporting a selective reduction of alveolar airspace. Furthermore, we found that administration of TNF-α, the bile acid, chenodeoxycholic acid, and FXR nuclear receptor activation (GW4064) induced apoptosis and impaired SP-B and SP-C production in alveolar epithelial cells in vitro. These results imply that AT2 cell dysfunction occurs in experimental HPS and is associated with alterations in the alveolar epithelial compartment. Our findings support a novel contributing mechanism in experimental HPS that may be relevant to humans and a potential therapeutic target. PMID:25419825

  16. Alveolar type II epithelial cell dysfunction in rat experimental hepatopulmonary syndrome (HPS).

    PubMed

    Yang, Wenli; Hu, Bingqian; Wu, Wei; Batra, Sachin; Blackburn, Michael R; Alcorn, Joseph L; Fallon, Michael B; Zhang, Junlan

    2014-01-01

    The hepatopulmonary syndrome (HPS) develops when pulmonary vasodilatation leads to abnormal gas exchange. However, in human HPS, restrictive ventilatory defects are also observed supporting that the alveolar epithelial compartment may also be affected. Alveolar type II epithelial cells (AT2) play a critical role in maintaining the alveolar compartment by producing four surfactant proteins (SPs, SP-A, SP-B, SP-C and SP-D) which also facilitate alveolar repair following injury. However, no studies have evaluated the alveolar epithelial compartment in experimental HPS. In this study, we evaluated the alveolar epithelial compartment and particularly AT2 cells in experimental HPS induced by common bile duct ligation (CBDL). We found a significant reduction in pulmonary SP production associated with increased apoptosis in AT2 cells after CBDL relative to controls. Lung morphology showed decreased mean alveolar chord length and lung volumes in CBDL animals that were not seen in control models supporting a selective reduction of alveolar airspace. Furthermore, we found that administration of TNF-α, the bile acid, chenodeoxycholic acid, and FXR nuclear receptor activation (GW4064) induced apoptosis and impaired SP-B and SP-C production in alveolar epithelial cells in vitro. These results imply that AT2 cell dysfunction occurs in experimental HPS and is associated with alterations in the alveolar epithelial compartment. Our findings support a novel contributing mechanism in experimental HPS that may be relevant to humans and a potential therapeutic target.

  17. An H3K9/S10 methyl-phospho switch modulates Polycomb and Pol II binding at repressed genes during differentiation.

    PubMed

    Sabbattini, Pierangela; Sjoberg, Marcela; Nikic, Svetlana; Frangini, Alberto; Holmqvist, Per-Henrik; Kunowska, Natalia; Carroll, Tom; Brookes, Emily; Arthur, Simon J; Pombo, Ana; Dillon, Niall

    2014-03-01

    Methylated histones H3K9 and H3K27 are canonical epigenetic silencing modifications in metazoan organisms, but the relationship between the two modifications has not been well characterized. H3K9me3 coexists with H3K27me3 in pluripotent and differentiated cells. However, we find that the functioning of H3K9me3 is altered by H3S10 phosphorylation in differentiated postmitotic osteoblasts and cycling B cells. Deposition of H3K9me3/S10ph at silent genes is partially mediated by the mitogen- and stress-activated kinases (MSK1/2) and the Aurora B kinase. Acquisition of H3K9me3/S10ph during differentiation correlates with loss of paused S5 phosphorylated RNA polymerase II, which is present on Polycomb-regulated genes in embryonic stem cells. Reduction of the levels of H3K9me3/S10ph by kinase inhibition results in increased binding of RNAPIIS5ph and the H3K27 methyltransferase Ezh1 at silent promoters. Our results provide evidence of a novel developmentally regulated methyl-phospho switch that modulates Polycomb regulation in differentiated cells and stabilizes repressed states.

  18. Cationic methyl complexes of the rare-earth metals: an experimental and computational study on synthesis, structure, and reactivity.

    PubMed

    Kramer, Mathias U; Robert, Dominique; Arndt, Stefan; Zeimentz, Peter M; Spaniol, Thomas P; Yahia, Ahmed; Maron, Laurent; Eisenstein, Odile; Okuda, Jun

    2008-10-20

    Synthesis, structure, and reactivity of two families of rare-earth metal complexes containing discrete methyl cations [LnMe(2-x)(thf)n]((1+x)+) (x = 0, 1; thf = tetrahydrofuran) have been studied. As a synthetic equivalent for the elusive trimethyl complex [LnMe3], lithium methylates of the approximate composition [Li3LnMe6(thf)n] were prepared by treating rare-earth metal trichlorides [LnCl3(thf)n] with 6 equiv of methyllithium in diethyl ether. Heteronuclear complexes of the formula [Li3Ln2Me9L(n)] (Ln = Sc, Y, Tb; L = Et2O, thf) were isolated by crystallization from diethyl ether. Single crystal X-ray diffraction studies revealed a heterometallic aggregate of composition [Li3Ln2Me9(thf)n(Et2O)m] with a [LiLn2Me9](2-) core (Ln = Sc, Y, Tb). When tris(tetramethylaluminate) [Ln(AlMe4)3] (Ln = Y, Lu) was reacted with less than 1 equiv of [NR3H][BPh4], the dimethyl cations [LnMe2(thf)n][BPh4] were obtained. The coordination number as well as cis/trans isomer preference was studied by crystallographic and computational methods. Dicationic methyl complexes of the rare-earth metals of the formula [LnMe(thf)n][BAr4]2 (Ln = Sc, Y, La-Nd, Sm, Gd-Lu; Ar = Ph, C6H4F-4) were synthesized, by protonolysis of either the ate complex [Li3LnMe6(thf)n] (Ln = Sc, Y, Gd-Lu) or the tris(tetramethylaluminate) [Ln(AlMe4)3] (Ln = La-Nd, Sm, Dy, Gd) with ammonium borates [NR3H][BAr4] in thf. The number of coordinated thf ligands varied from n = 5 (Ln = Sc, Tm) to n = 6 (Ln = La, Y, Sm, Dy, Ho). The configuration of representative examples was determined by X-ray diffraction studies and confirmed by density-functional theory calculations. The highly polarized bonding between the methyl group and the rare-earth metal center results in the reactivity pattern dominated by the carbanionic character and the pronounced Lewis acidity: The dicationic methyl complex [YMe(thf)6](2+) inserted benzophenone as an electrophile to give the alkoxy complex [Y(OCMePh2)(thf)5](2+). Nucleophilic addition of

  19. {(E)-4-Hy-droxy-N'-[phen-yl(pyridin-2-yl-κN)methyl-idene]benzohydrazide-κN',O}bis-(nitrato-κO,O')copper(II).

    PubMed

    Bikas, Rahman; Sattari, Farhad; Notash, Behrouz

    2012-02-01

    In the title compound, [Cu(NO(3))(2)(C(19)H(15)N(3)O(2))], the coordination geometry around the Cu(II) ion can be described as distorted square-pyramidal, with two N atoms and one O atom from an (E)-4-hy-droxy-N'-[phen-yl(pyridin-2-yl)methyl-ene]benzohydrazide ligand and one nitrate O atom in the basal plane and one nitrate O atom at the apical site. The other two nitrate O atoms also bind to the Cu atom with long Cu-O distances [2.607 (4) and 2.853 (5) Å]. The crystal packing is stabilized by inter-molecular N-H⋯O and O-H⋯O hydrogen bonds. PMID:22346817

  20. Crystal structure of di­chlorido­bis­(N,N′-di­methyl­thio­urea-κS)mercury(II)

    PubMed Central

    Shaheen, Muhammad Ashraf; Munawar, Aisha; Sadaf, Haseeba; Tahir, Muhammad Nawaz; Isab, Anvarhusein A.; Ahmad, Saeed

    2015-01-01

    The mol­ecular structure of the title compound, [HgCl2(C3H8N2S)2], has point group symmetry 2, with the twofold rotation axis passing through the HgII atom. The latter is coordinated by two Cl atoms and two N,N′-di­methyl­thio­urea (Dmtu) ligands through their S atoms, defining a distorted tetra­hedral coordination sphere with bond angles in the range 102.47 (4)–118.32 (4)°. Intra- and inter­molecular hydrogen bonds of the type N—H⋯Cl with S(6) and R 2 2(12) ring motifs are present. The inter­molecular contacts make up polymeric chains extending parallel to [101]. PMID:26396848

  1. Facile "living" radical polymerization of methyl methacrylate in the presence of iniferter agents: homogeneous and highly efficient catalysis from copper(II) acetate.

    PubMed

    Jiang, Hongjuan; Zhang, Lifen; Jiang, Xiaowu; Bao, Xiaoguang; Cheng, Zhenping; Zhu, Xiulin

    2014-08-01

    A facile homogeneous polymerization system involving the iniferter agent 1-cyano-1-methylethyl diethyldithiocarbamate (MANDC) and copper(II) acetate (Cu(OAc)2 ) is successfully developed in bulk using methyl methacylate (MMA) as a model monomer. The detailed polymerization kinetics with different molar ratios (e.g., [MMA]0 /[MANDC]0 /[Cu(OAc)2 ]0 = 500/1/x (x = 0.1, 0.2, 0.5, 1.0)) demonstrate that this system has the typical "living"/controlled features of "living" radical polymerization, even with ppm level catalyst Cu(OAc)2 , first order polymerization kinetics, a linear increase in molecular weight with monomer conversion and narrow molecular weight distributions for the resultant PMMA. (1) H NMR spectra and chain-extension experiments further confirm the "living" characteristics of this process. A plausible mechanism is discussed.

  2. Chlorido(4-methylpyridin-2-amine-κN 1)(2-{[(4-methylpyridin-2-yl)imino-κN]methyl}phenolato-κO)copper(II)

    PubMed Central

    Bhagyaraju, Bussa; Sambasiva Rao, P.; Swu, Toka

    2012-01-01

    In the title complex, [Cu(C13H11N2O)Cl(C6H8N2)], the CuII atom adopts a distorted tetra­hedral geometry being coordinated by the phenolic O atom and the azomethine N atom of the Schiff base ligand N-salicyl­idene 2-amino­pyridine, and by the 2-amino­pyridine N atom and a Cl atom. The pyridyl N atom of the Schiff base and the imino N atom of the 4-methyl-pyridine-2-yl­imino ligand are not involved in the coordination. There is an intra­molecular N—H⋯N hydrogen bond involving the pyridine N atom and the amino group of the 2-amino­pyridine ligand. In the crystal, mol­ecules are linked via N—H⋯Cl hydrogen bonds, forming chains propagating along [001]. PMID:23468733

  3. Changes in DNA methylation and transgenerational mobilization of a transposable element (mPing) by the Topoisomerase II inhibitor, Etoposide, in rice

    PubMed Central

    2012-01-01

    Background Etoposide (epipodophyllotoxin) is a chemical commonly used as an anti-cancer drug which inhibits DNA synthesis by blocking topoisomerase II activity. Previous studies in animal cells have demonstrated that etoposide constitutes a genotoxic stress which may induce genomic instability including mobilization of normally quiescent transposable elements (TEs). However, it remained unknown whether similar genetically mutagenic effects could be imposed by etoposide in plant cells. Also, no information is available with regard to whether the drug may cause a perturbation of epigenetic stability in any organism. Results To investigate whether etoposide could generate genetic and/or epigenetic instability in plant cells, we applied etoposide to germinating seeds of six cultivated rice (Oryza sativa L.) genotypes including both subspecies, japonica and indica. Based on the methylation-sensitive gel-blotting results, epigenetic changes in DNA methylation of three TEs (Tos17, Osr23 and Osr36) and two protein-encoding genes (Homeobox and CDPK-related genes) were detected in the etoposide-treated plants (S0 generation) in four of the six studied japonica cultivars, Nipponbare, RZ1, RZ2, and RZ35, but not in the rest japonica cultivar (Matsumae) and the indica cultivar (93-11). DNA methylation changes in the etoposide-treated S0 rice plants were validated by bisulfite sequencing at both of two analyzed loci (Tos17 and Osr36). Transpositional activity was tested for eight TEs endogenous to the rice genome in both the S0 plants and their selfed progenies (S1 and S2) of one of the cultivars, RZ1, which manifested heritable phenotypic variations. Results indicated that no transposition occurred in the etoposide-treated S0 plants for any of the TEs. Nonetheless, a MITE transposon, mPing, showed rampant mobilization in the S1 and S2 progenies descended from the drug-treated S0 plants. Conclusions Our results demonstrate that etoposide imposes a similar genotoxic stress on

  4. Comparison of reactivity of Pt(II) center in the mononuclear and binuclear organometallic diimineplatinum complexes toward oxidative addition of methyl iodide

    NASA Astrophysics Data System (ADS)

    Hashemi, Majid

    2016-01-01

    The reactivities of Pt(II) center in a series of organometallic mononuclear Pt(II), binuclear Pt(II) and binuclear mixed-valence Pt(II)-Pt(IV) complexes toward oxidative addition of MeI have been compared from a theoretical point of view. The nucleophilicity index and electron-donation power were calculated for each of these complexes. The energies of HOMO and dZ2 orbital were determined for these complexes. Very good correlations were found between logk2 (k2 is the experimentally determined second order rate constant for the oxidative addition of MeI on these complexes) and nucleophilicity index or electron-donation power for these complexes. The correlation between logk2 and the energy of HOMO or the energy of dZ2 orbital were also very good. The condensed-to-atom Fukui functions for electrophilic attack on these complexes showed that the Pt(II) center is the preferred site for the oxidative addition of MeI. All of these observations are in agreement with the proposed SN2 type mechanism in the oxidative addition of MeI on the Pt(II) center in these complexes.

  5. Isomeric luminescent Zn(II) coordination polymers based on pyridinecarboxylate and 5-methyl-1H-tetrazole ligands

    NASA Astrophysics Data System (ADS)

    An, Zhe; Gao, Jing; Zhu, Ling

    2013-12-01

    Two new metal-organic frameworks, namely [Zn(nic)(mtz)]n (1) and [Zn(isonic)(mtz)]n (2) (Hnic = nicotinic acid, Hisonic = isonicotinic acid, Hmtz = 5-methyl-1H-tetrazole), have been obtained through the solvothermal reactions of Zn(NO3)2, Htmz and Hnic or Hisonic. Single crystal X-ray diffraction analysis reveals that compound 1 features a 2D layered structure with sql topology, which is further extended into a 3D supramolecular framework via weak CH…π interactions, and compound 2 is 2-fold interpenetrated 3D framework with dia topology. Luminescent investigation shows that both of them emit blue luminescence at room temperature.

  6. Methionine Adenosyltransferase II-dependent Histone H3K9 Methylation at the COX-2 Gene Locus*

    PubMed Central

    Kera, Yohei; Katoh, Yasutake; Ohta, Mineto; Matsumoto, Mitsuyo; Takano-Yamamoto, Teruko; Igarashi, Kazuhiko

    2013-01-01

    Methionine adenosyltransferase (MAT) synthesizes S-adenosylmethionine (AdoMet), which is utilized as a methyl donor in transmethylation reactions involving histones. MATIIα, a MAT isozyme, serves as a transcriptional corepressor in the oxidative stress response and forms the AdoMet-integrating transcription regulation module, affecting histone methyltransferase activities. However, the identities of genes regulated by MATIIα or its associated methyltransferases are unclear. We show that MATIIα represses the expression of cyclooxygenase 2 (COX-2), encoded by Ptgs2, by specifically interacting with histone H3K9 methyltransferase SETDB1, thereby promoting the trimethylation of H3K9 at the COX-2 locus. We discuss both gene-specific and epigenome-wide functions of MATIIα. PMID:23539621

  7. Polarized light scanning cryomacroscopy, part II: Thermal modeling and analysis of experimental observations.

    PubMed

    Feig, Justin S G; Solanki, Prem K; Eisenberg, David P; Rabin, Yoed

    2016-10-01

    This study aims at developing thermal analysis tools and explaining experimental observations made by means of polarized-light cryomacroscopy (Part I). Thermal modeling is based on finite elements analysis (FEA), where two model parameters are extracted from thermal measurements: (i) the overall heat transfer coefficient between the cuvette and the cooling chamber, and (ii) the effective thermal conductivity within the cryoprotective agent (CPA) at the upper part of the cryogenic temperature range. The effective thermal conductivity takes into account enhanced heat transfer due to convection currents within the CPA, creating the so-called Bénard cells. Comparison of experimental results with simulation data indicates that the uncertainty in simulations due to the propagation of uncertainty in measured physical properties exceeds the uncertainty in experimental measurements, which validates the modeling approach. It is shown in this study that while a cavity may form in the upper-center portion of the vitrified CPA, it has very little effect on estimating the temperature distribution within the domain. This cavity is driven by thermal contraction of the CPA, with the upper-center of the domain transitioning to glass last. Finally, it is demonstrated in this study that additional stresses may develop within the glass transition temperature range due to nonlinear behavior of the thermal expansion coefficient. This effect is reported here for the first time in the context of cryobiology, using the capabilities of polarized-light cryomacroscopy. PMID:27343139

  8. Polarized light scanning cryomacroscopy, part II: Thermal modeling and analysis of experimental observations.

    PubMed

    Feig, Justin S G; Solanki, Prem K; Eisenberg, David P; Rabin, Yoed

    2016-10-01

    This study aims at developing thermal analysis tools and explaining experimental observations made by means of polarized-light cryomacroscopy (Part I). Thermal modeling is based on finite elements analysis (FEA), where two model parameters are extracted from thermal measurements: (i) the overall heat transfer coefficient between the cuvette and the cooling chamber, and (ii) the effective thermal conductivity within the cryoprotective agent (CPA) at the upper part of the cryogenic temperature range. The effective thermal conductivity takes into account enhanced heat transfer due to convection currents within the CPA, creating the so-called Bénard cells. Comparison of experimental results with simulation data indicates that the uncertainty in simulations due to the propagation of uncertainty in measured physical properties exceeds the uncertainty in experimental measurements, which validates the modeling approach. It is shown in this study that while a cavity may form in the upper-center portion of the vitrified CPA, it has very little effect on estimating the temperature distribution within the domain. This cavity is driven by thermal contraction of the CPA, with the upper-center of the domain transitioning to glass last. Finally, it is demonstrated in this study that additional stresses may develop within the glass transition temperature range due to nonlinear behavior of the thermal expansion coefficient. This effect is reported here for the first time in the context of cryobiology, using the capabilities of polarized-light cryomacroscopy.

  9. Systemic Pulsatile Pressure in Type II Endoleaks After Stent Grafting of Experimental Abdominal Aortic Aneurysms

    SciTech Connect

    Pitton, Michael Bernhard Schmenger, Patrick; Dueber, Christoph; Neufang, Achim; Thelen, Manfred

    2003-06-15

    Purpose: To investigate pressure and maximum rate of rise of systolic pressure (peak dP/dt) in completely excluded aneurysms and endoleaks to determine the hemodynamic impact of endoleaks. Methods: In mongrel dogs (n =36) experimental aneurysms were created by insertion of a patch (portion of rectus abdomen is muscle sheath) into the infrarenalaorta. In group I (n 18), all aortic branches of the aneurysm were ligated and all aneurysms were completely excluded by stent grafts. Group II (n = 18) consisted of aneurysms with patent aortic side branches that represented sources of endoleaks.One week (n = 12), six weeks (n = 12),and six months (n = 12) after stent grafting,hemodynamic measurements were obtained in thrombosed aneurysms and proved endoleaks. Systemic blood pressure and intraaneurysmal pressure were simultaneously measured and the respective peak dP/dt were computed. Results: At the six-month follow-up, the systolic-pressure ratio (intraaneurysmatic pressure: systemic pressure)was significantly increased in endoleaks compared to non-perfused areas(0.879 {+-} 0.042 versus 0.438 {+-} 0.176, p <0.01, group II) or completely excluded aneurysms (0.385 {+-}0.221, group I). Peak dP/dt ratio (intraaneurysmal peak dP/dt: systemic peak dP/dt) was 0.922 {+-} 0.154 in endoleaks, compared to 0.084 {+-} 0.080 in non-perfused areas (group II, p <0.01), and was 0.146 {+-} 0.121 in completely excluded aneurysms (group I). The diastolic-pressure ratio was also increased inendoleaks compared to non-perfused areas (0.929 {+-} 0.088 versus 0.655 {+-} 0.231, p < 0.01, group II) or completely excluded aneurysms (0.641 {+-} 0.278, group I). In excluded aneurysms, pressure exposure declined as the length of the follow-up period increased. Conclusion: Type II endoleaks transmit pulsatile pressure of near systemic level and indicate insufficient treatment result. In contrast, complete endovascular exclusion of aneurysms results in significantly reduced pressure exposure.

  10. Synthesis, characterization and properties of tetra((1-hydroxyimino-methylnaphthalen-2-yloxy)methyl)ethene and its homo-dinuclear metal complexes: A combined experimental and theoretical investigation

    NASA Astrophysics Data System (ADS)

    Serbest, Kerim; Karaoğlu, Kaan; Erman, Murat; Er, Mustafa; Değirmencioğlu, İsmail

    2010-10-01

    Tetra((1-hydroxyiminomethylnaphthalen-2-yloxy)methyl)ethene (THIMNYOME), H 4L, was synthesized by the agents of 2-hydroxy-1-naphtaldehyde, tetra(bromomethyl)ethene and hydroxylamine hydrochloride in two steps. Characterization of THIMNYOME and its dinuclear complexes was made by elemental analyses, IR, 1H- and 13C NMR, UV-vis, electrospray ionisation mass spectra, molar conductivities and magnetic susceptibility measurements. In the light of these results, it was suggested that the ligand coordinate to each metal atom by the two ether oxygen, two nitrogen atoms of oxime imine (C dbnd N) and an axial oxygen of perchlorate to form pseudo square-pyramidal complexes with Ni(II), Cu(II) and Zn(II). Molar conductivity measurements reveal that all the complexes are non-electrolytes. In addition, the full geometric optimization of the tetraoxime ligand ( 4) has been made by the B3LYP/6-31G(d) level in order to establish a stable conformation. Additionally, all the complex structures have been studied in the B3LYP/LANL2DZ level. NBO charge distribution and the characteristics of frontier molecular orbitals of these complexes have also been investigated in order to see the electrons movement between ligand and metal atom in the same level.

  11. Synthesis and spectral characterization of mono- and binuclear copper(II) complexes derived from 2-benzoylpyridine-N4-methyl-3-thiosemicarbazone: Crystal structure of a novel sulfur bridged copper(II) box-dimer

    NASA Astrophysics Data System (ADS)

    Jayakumar, K.; Sithambaresan, M.; Aiswarya, N.; Kurup, M. R. Prathapachandra

    2015-03-01

    Mononuclear and binuclear copper(II) complexes of 2-benzoylpyridine-N4-methyl thiosemicarbazone (HL) were prepared and characterized by a variety of spectroscopic techniques. Structural evidence for the novel sulfur bridged copper(II) iodo binuclear complex is obtained by single crystal X-ray diffraction analysis. The complex [Cu2L2I2], a non-centrosymmetric box dimer, crystallizes in monoclinic C2/c space group and it was found to have distorted square pyramidal geometry (Addison parameter, τ = 0.238) with the square basal plane occupied by the thiosemicarbazone moiety and iodine atom whereas the sulfur atom from the other coordinated thiosemicarbazone moiety occupies the apical position. This is the first crystallographically studied system having non-centrosymmetrical entities bridged via thiolate S atoms with Cu(II)sbnd I bond. The tridentate thiosemicarbazone coordinates in mono deprotonated thionic tautomeric form in all complexes except in sulfato complex, [Cu(HL)(SO4)]·H2O (1) where it binds to the metal centre in neutral form. The magnetic moment values and the EPR spectral studies reflect the binuclearity of some of the complexes. The spin Hamiltonian and bonding parameters are calculated based on EPR studies. In all the complexes g|| > g⊥ > 2.0023 and the g values in frozen DMF are consistent with the dx2-y2 ground state. The thermal stabilities of some of the complexes were also determined.

  12. ENZYMOLOGY OF ARSENIC METHYLATION

    EPA Science Inventory

    Enzymology of Arsenic Methylation

    David J. Thomas, Pharmacokinetics Branch, Experimental Toxicology Division, National
    Health and Environmental Effects Research Laboratory, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park...

  13. Experimental implementation of edge nodes for an OPS system based on Nios II

    NASA Astrophysics Data System (ADS)

    Li, Xiaoyun; Xu, Bo; Qiu, Kun; Zhou, Heng

    2008-12-01

    The advantages of Optical Packet Switching (OPS) are transparent data transmission and data format, flexible packet control and dynamic resource allocation. It thus can support high-speed transmission of wideband data networks. Unlike Optical Burst Switching (OBS) systems which need reserved channel to transmit destination address, an advanced OPS solution using Optical Orthogonal Code (OOC) label for payload transfer has been proposed in this paper. Different from other OPS systems, our edge nodes are required to realize some special tasks including extracting destination addresses of the received IP packet which is used as payload in our OPS systems and sending the addresses to the OOC label generator. The OOC label will later be used to identify the destination of each payload at the core node for optical switching. Meanwhile, the higher-priority flow can be prior-serviced according to the Type of Service (TOS) in the head of IP packet. It is experimentally shown that the edge nodes in this OPS system can effectively improve the efficiency of packet switching and the speed of data transmission. The edge node implementation contains two parts: the hardware and software. For the hardware part, all necessary modules have been integrated onto one PCB board, thus avoiding possible instability caused by interconnecting different modules like transmitting/receiving Ethernet frame module, Field Programmable Gate Array (FPGA) processing module and optical transceiver module etc. from different Printed Circuit Boards (PCB). For the software part, the whole of system was based on MicroC/OS-II operating systems running on the Nios II soft core processor. It is verified by the experiment that embedded system designed with Nios II soft core CPU can help to speed up the hardware design. With the SOPC Builder's development environment, more attention can be paid to the structure and function of the system without worrying about the details of the circuit design, and better

  14. An experimental system for spectral line ratio measurements in the TJ-II stellarator

    SciTech Connect

    Zurro, B.; Baciero, A.; Fontdecaba, J. M.; Jimenez-Rey, D.; Pelaez, R.

    2008-10-15

    The chord-integrated emissions of spectral lines have been monitored in the TJ-II stellarator by using a spectral system with time and space scanning capabilities and relative calibration over the entire UV-visible spectral range. This system has been used to study the line ratio of lines of different ionization stages of carbon (C{sup 5+} 5290 A and C{sup 4+} 2271 A) for plasma diagnostic purposes. The local emissivity of these ions has been reconstructed, for quasistationary profiles, by means of the inversion Fisher method described previously. The experimental line ratio is being empirically studied and in parallel a simple spectroscopic model has been developed to account for that ratio. We are investigating whether the role played by charge exchange processes with neutrals and the existence of non-Maxwellian electrons, intrinsic to Electron Cyclotron Resonance Heating (ECRH) heating, leave any distinguishable mark on this diagnostic method.

  15. Experimental power density distribution benchmark in the TRIGA Mark II reactor

    SciTech Connect

    Snoj, L.; Stancar, Z.; Radulovic, V.; Podvratnik, M.; Zerovnik, G.; Trkov, A.; Barbot, L.; Domergue, C.; Destouches, C.

    2012-07-01

    In order to improve the power calibration process and to benchmark the existing computational model of the TRIGA Mark II reactor at the Josef Stefan Inst. (JSI), a bilateral project was started as part of the agreement between the French Commissariat a l'energie atomique et aux energies alternatives (CEA) and the Ministry of higher education, science and technology of Slovenia. One of the objectives of the project was to analyze and improve the power calibration process of the JSI TRIGA reactor (procedural improvement and uncertainty reduction) by using absolutely calibrated CEA fission chambers (FCs). This is one of the few available power density distribution benchmarks for testing not only the fission rate distribution but also the absolute values of the fission rates. Our preliminary calculations indicate that the total experimental uncertainty of the measured reaction rate is sufficiently low that the experiments could be considered as benchmark experiments. (authors)

  16. The FERRUM project: Experimental transition probabilities from highly excited even 5s levels in Cr ii

    NASA Astrophysics Data System (ADS)

    Engström, L.; Lundberg, H.; Nilsson, H.; Hartman, H.; Bäckström, E.

    2014-10-01

    We report lifetime measurements of the five levels in the 3d4(a5D)5s e6D term in Cr ii at an energy around 83 000 cm-1, and log(gf) values for 38 transitions from the investigated levels. The lifetimes are obtained using time-resolved, laser-induced fluorescence on ions from a laser-produced plasma. Since the levels have the same parity as the low-lying states directly populated in the plasma, we used a two-photon excitation scheme. This process is greatly facilitated by the presence of the 3d4(a5D)4p z6F levels at roughly half the energy difference. The f-values are obtained by combining the experimental lifetimes with branching fractions derived using relative intensities from a hollow cathode lamp recorded with a Fourier transform spectrometer.

  17. The role of atomic lines in radiation heating of the experimental space vehicle Fire-II

    NASA Astrophysics Data System (ADS)

    Surzhikov, S. T.

    2015-10-01

    The results of calculating the convective and radiation heating of the Fire-II experimental space vehicle allowing for atomic lines of atoms and ions using the NERAT-ASTEROID computer platform are presented. This computer platform is intended to solve the complete set of equations of radiation gas dynamics of viscous, heat-conductive, and physically and chemically nonequilibrium gas, as well as radiation transfer. The spectral optical properties of high temperature gases are calculated using ab initio quasi-classical and quantum-mechanical methods. The calculation of the transfer of selective thermal radiation is performed using a line-by-line method using specially generated computational grids over the radiation wavelengths, which make it possible to attain a noticeable economy of computational resources.

  18. Experimental diagenesis of organo-mineral structures formed by microaerophilic Fe(II)-oxidizing bacteria.

    PubMed

    Picard, Aude; Kappler, Andreas; Schmid, Gregor; Quaroni, Luca; Obst, Martin

    2015-01-01

    Twisted stalks are organo-mineral structures produced by some microaerophilic Fe(II)-oxidizing bacteria at O2 concentrations as low as 3 μM. The presence of these structures in rocks having experienced a diagenetic history could indicate microbial Fe(II)-oxidizing activity as well as localized abundance of oxygen at the time of sediment deposition. Here we use spectroscopy and analytical microscopy to evaluate if--and what kind of--transformations occur in twisted stalks through experimental diagenesis. Unique mineral textures appear on stalks as temperature and pressure conditions increase. Haematite and magnetite form from ferrihydrite at 170 °C-120 MPa. Yet the twisted morphology of the stalks, and the organic matrix, mainly composed of long-chain saturated aliphatic compounds, are preserved at 250 °C-140 MPa. Our results suggest that iron minerals might play a role in maintaining the structural and chemical integrity of stalks under diagenetic conditions and provide spectroscopic signatures for the search of ancient life in the rock record. PMID:25692888

  19. Synthesis and characterization of poly(methyl methacrylate)-based experimental bone cements reinforced with TiO2-SrO nanotubes.

    PubMed

    Khaled, S M Z; Charpentier, Paul A; Rizkalla, Amin S

    2010-08-01

    In an attempt to overcome existing limitations of experimental bone cements we here demonstrate a simple approach to synthesizing strontium-modified titania nanotubes (n-SrO-TiO(2) tubes) and functionalize them using the bifunctional monomer methacrylic acid. Then, using 'grafting from' polymerization with methyl methacrylate, experimental bone cements were produced with excellent mechanical properties, radiopacity and biocompatibility. Transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive spectroscopy mapping and backscattered SEM micrographs revealed a uniform distribution of SrO throughout the titanium matrix, with retention of the nanotubular morphology. Nanocomposites were then reinforced with 1, 2, 4 and 6 wt.% of the functionalized metal oxide nanotubes. Under the mixing and dispersion regime employed in this study, 2 wt.% appeared optimal, exhibiting a more uniform dispersion and stronger adhesion of the nanotubes in the poly(methyl methacrylate) matrix, as shown by TEM and SEM. Moreover, this optimum loading provided a significant increase in the fracture toughness (K(IC)) (20%) and flexural strength (40%) in comparison with the control matrix (unfilled) at P<0.05. Examination of the fracture surfaces by SEM showed that toughening was provided by the nanotubes interlocking with the acrylic matrix and crack bridging during fracture. On modifying the n-TiO(2) tubes with strontium oxide the nanocomposites exhibited a similar radiopacity to a commercial bone cement (CMW 1), while exhibiting a significant enhancement of osteoblast cell proliferation (242%) in vitro compared with the control at P<0.05. PMID:20170759

  20. Crystal structure of bis-(1-hexyl-N,N-di-methyl-pyridinium) bis-(maleo-nitrile-dithiol-ato)nickelate(II).

    PubMed

    Yu, Shan-Shan; Zhang, Hui

    2016-08-01

    The asymmetric unit of the title compound, (C13H23N2)2[Ni(C4N2S2)2], consists of a 1-hexyl-N,N-di-methyl-pyridinium cation and one half of a [Ni(mnt)2](2-) dianion (mnt(2-) = maleo-nitrile-dithiol-ate) in which the Ni(2+) cation lies on a crystallographic inversion centre. The square-planar coordination about Ni(2+) comprises four S atoms from two bidentate chelate mnt(2-) ligands [Ni-S = 2.1791 (9) and 2.1810 (8) Å, and S-Ni-S bite angle = 91.93 (3)°]. The hydro-carbon chains of cations show trans-planar conformations and lie approximately parallel to the long mol-ecular axis of the [Ni(mnt)2](2-) anions, giving stacks along the c axis. The anions and cations form layers lying parallel to the bc plane. Only weak C-H⋯Ni and C-H⋯π associations are present in the crystal packing. PMID:27536413

  1. Dicopper(II) metallacyclophanes as multifunctional magnetic devices: a joint experimental and computational study.

    PubMed

    Castellano, María; Ruiz-García, Rafael; Cano, Joan; Ferrando-Soria, Jesús; Pardo, Emilio; Fortea-Pérez, Francisco R; Stiriba, Salah-Eddine; Julve, Miguel; Lloret, Francesc

    2015-03-17

    Metallosupramolecular complexes constitute an important advance in the emerging fields of molecular spintronics and quantum computation and a useful platform in the development of active components of spintronic circuits and quantum computers for applications in information processing and storage. The external control of chemical reactivity (electro- and photochemical) and physical properties (electronic and magnetic) in metallosupramolecular complexes is a current challenge in supramolecular coordination chemistry, which lies at the interface of several other supramolecular disciplines, including electro-, photo-, and magnetochemistry. The specific control of current flow or spin delocalization through a molecular assembly in response to one or many input signals leads to the concept of developing a molecule-based spintronics that can be viewed as a potential alternative to the classical molecule-based electronics. A great variety of factors can influence over these electronically or magnetically coupled, metallosupramolecular complexes in a reversible manner, electronic or photonic external stimuli being the most promising ones. The response ability of the metal centers and/or the organic bridging ligands to the application of an electric field or light irradiation, together with the geometrical features that allow the precise positioning in space of substituent groups, make these metal-organic systems particularly suitable to build highly integrated molecular spintronic circuits. In this Account, we describe the chemistry and physics of dinuclear copper(II) metallacyclophanes with oxamato-containing dinucleating ligands featuring redox- and photoactive aromatic spacers. Our recent works on dicopper(II) metallacyclophanes and earlier ones on related organic cyclophanes are now compared in a critical manner. Special focus is placed on the ligand design as well as in the combination of experimental and computational methods to demonstrate the multifunctionality

  2. Measurement of methyl mercury (I) and mercury (II) in fish tissues and sediments by HPLC-ICPMS and HPLC-HGAAS.

    PubMed

    Jagtap, Rajani; Krikowa, Frank; Maher, William; Foster, Simon; Ellwood, Michael

    2011-07-15

    A procedure for the extraction and determination of methyl mercury and mercury (II) in fish muscle tissues and sediment samples is presented. The procedure involves extraction with 5% (v/v) 2-mercaptoethanol, separation and determination of mercury species by HPLC-ICPMS using a Perkin-Elmer 3 μm C8 (33 mm×3 mm) column and a mobile phase 3 containing 0.5% (v/v) 2-mercaptoethanol and 5% (v/v) CH(3)OH (pH 5.5) at a flow rate 1.5 ml min(-1) and a temperature of 25°C. Calibration curves for methyl mercury (I) and mercury (II) standards were linear in the range of 0-100 μgl(-1) (r(2)=0.9990 and r(2)=0.9995 respectively). The lowest measurable mercury was 0.4 μgl(-1) which corresponds to 0.01 μgg(-1) in fish tissues and sediments. Methyl mercury concentrations measured in biological certified reference materials, NRCC DORM - 2 Dogfish muscle (4.4±0.8 μgg(-1)), NRCC Dolt - 3 Dogfish liver (1.55±0.09 μgg(-1)), NIST RM 50 Albacore Tuna (0.89±0.08 μgg(-1)) and IRMM IMEP-20 Tuna fish (3.6±0.6 μgg(-1)) were in agreement with the certified value (4.47±0.32μgg(-1), 1.59±0.12 μgg(-1), 0.87±0.03 μgg(-1), 4.24±0.27 μgg(-1) respectively). For the sediment reference material ERM CC 580, a methyl mercury concentration of 0.070±0.002 μgg(-1) was measured which corresponds to an extraction efficiency of 92±3% of certified values (0.076±0.04 μgg(-1)) but within the range of published values (0.040-0.084 μgg(-1); mean±s.d.: 0.073±0.05 μgg(-1), n=40) for this material. The extraction procedure for the fish tissues was also compared against an enzymatic extraction using Protease type XIV that has been previously published and similar results were obtained. The use of HPLC-HGAAS with a Phenomenox 5 μm Luna C18 (250 mm×4.6 mm) column and a mobile phase containing 0.06 moll(-1) ammonium acetate (Merck Pty Limited, Australia) in 5% (v/v) methanol and 0.1% (w/v) l-cysteine at 25°C was evaluated as a complementary alternative to HPLC-ICPMS for the measurement of

  3. Measurement of methyl mercury (I) and mercury (II) in fish tissues and sediments by HPLC-ICPMS and HPLC-HGAAS.

    PubMed

    Jagtap, Rajani; Krikowa, Frank; Maher, William; Foster, Simon; Ellwood, Michael

    2011-07-15

    A procedure for the extraction and determination of methyl mercury and mercury (II) in fish muscle tissues and sediment samples is presented. The procedure involves extraction with 5% (v/v) 2-mercaptoethanol, separation and determination of mercury species by HPLC-ICPMS using a Perkin-Elmer 3 μm C8 (33 mm×3 mm) column and a mobile phase 3 containing 0.5% (v/v) 2-mercaptoethanol and 5% (v/v) CH(3)OH (pH 5.5) at a flow rate 1.5 ml min(-1) and a temperature of 25°C. Calibration curves for methyl mercury (I) and mercury (II) standards were linear in the range of 0-100 μgl(-1) (r(2)=0.9990 and r(2)=0.9995 respectively). The lowest measurable mercury was 0.4 μgl(-1) which corresponds to 0.01 μgg(-1) in fish tissues and sediments. Methyl mercury concentrations measured in biological certified reference materials, NRCC DORM - 2 Dogfish muscle (4.4±0.8 μgg(-1)), NRCC Dolt - 3 Dogfish liver (1.55±0.09 μgg(-1)), NIST RM 50 Albacore Tuna (0.89±0.08 μgg(-1)) and IRMM IMEP-20 Tuna fish (3.6±0.6 μgg(-1)) were in agreement with the certified value (4.47±0.32μgg(-1), 1.59±0.12 μgg(-1), 0.87±0.03 μgg(-1), 4.24±0.27 μgg(-1) respectively). For the sediment reference material ERM CC 580, a methyl mercury concentration of 0.070±0.002 μgg(-1) was measured which corresponds to an extraction efficiency of 92±3% of certified values (0.076±0.04 μgg(-1)) but within the range of published values (0.040-0.084 μgg(-1); mean±s.d.: 0.073±0.05 μgg(-1), n=40) for this material. The extraction procedure for the fish tissues was also compared against an enzymatic extraction using Protease type XIV that has been previously published and similar results were obtained. The use of HPLC-HGAAS with a Phenomenox 5 μm Luna C18 (250 mm×4.6 mm) column and a mobile phase containing 0.06 moll(-1) ammonium acetate (Merck Pty Limited, Australia) in 5% (v/v) methanol and 0.1% (w/v) l-cysteine at 25°C was evaluated as a complementary alternative to HPLC-ICPMS for the measurement of

  4. Synthesis, spectral and quantum chemical studies and use of (E)-3-[(3,5-bis(trifluoromethyl)phenylimino)methyl]benzene-1,2-diol and its Ni(II) and Cu(II) complexes as an anion sensor, DNA binding, DNA cleavage, anti-microbial, anti-mutagenic and anti-cancer agent

    NASA Astrophysics Data System (ADS)

    Ünver, Hüseyin; Boyacıoğlu, Bahadır; Zeyrek, Celal Tuğrul; Yıldız, Mustafa; Demir, Neslihan; Yıldırım, Nuray; Karaosmanoğlu, Oğuzhan; Sivas, Hülya; Elmalı, Ayhan

    2016-12-01

    We report the synthesis of a novel Schiff base (E)-3-[(3,5-bis(trifluoromethyl) phenylimino)methyl] benzene-1,2-diol from the reaction of 2,3-dihydroxybenzaldehyde with 3,5-bis(trifluoromethyl)aniline, and its Ni(II) and Cu(II) complexes. The molecular structure of the Schiff base was experimentally determined using X-ray single-crystal data and was compared to the structure predicted by theoretical calculations using density functional theory (DFT), Hartree-Fock (HF) and Möller-Plesset second-order perturbation (MP2). In addition, nonlinear optical (NLO) effects of the compound was predicted using DFT. The antimicrobial activities of the compounds were investigated for their minimum inhibitory concentration. UV-Vis spectroscopy studies of the interactions between the compounds and calf thymus DNA (CT-DNA) showed that the compounds interacts with CT-DNA via intercalative binding. A DNA cleavage study showed that the Cu(II) complex cleaved DNA without any external agents. The compounds inhibited the base pair mutation in the absence of S9 with high inhibition rate. In addition, in vitro cytotoxicity of the Ni(II) complex towards HepG2 cell line was assayed by the MTT method. Also, the colorimetric response of the Schiff base in DMSO to the addition of equivalent amount of anions (F-, Br-, I-, CN-, SCN-, ClO4-, HSO4-, AcO-, H2PO4-, N3- and OH-) was investigated. In this regard, while the addition of F-, CN-, AcO- and OH- anions into the solution containing Schiff base resulted in a significant color change, the addition of Br-, I-, SCN-, ClO4-, HSO4-, H2PO4- and N3- anions resulted in no color change. The most discernable color change in the Schiff base was caused by CN-, which demonstrated that the ligand can be used to selectively detect CN-.

  5. Lithium Di- and trimethyl dimolybdenum(II) complexes with Mo-Mo quadruple bonds and bridging methyl groups.

    PubMed

    Curado, Natalia; Carrasco, Mario; Álvarez, Eleuterio; Maya, Celia; Peloso, Riccardo; Rodríguez, Amor; López-Serrano, Joaquín; Carmona, Ernesto

    2015-09-30

    New dimolybdenum complexes of composition [Mo2{μ-Me}2Li(S)}(μ-X)(μ-N^N)2] (3a-3c), where S = THF or Et2O and N^N represents a bidentate aminopyridinate or amidinate ligand that bridges the quadruply bonded molybdenum atoms, were prepared from the reaction of the appropriate [Mo2{μ-O2CMe}2(μ-N^N)2] precursors and LiMe. For complex 3a, X = MeCO2, while in 3b and 3c, X = Me. Solution NMR studies in C6D6 solvent support formulation of the complexes as contact ion pairs with weak agostic Mo-CH3···Li interactions, which were also evidenced by X-ray crystallography in the solid-state structures of the molecules of 3a and 3b. Samples of 3c enriched in (13)C (99%) at the metal-bonded methyl sites were also prepared and investigated by NMR spectroscopy employing C6D6 and THF-d8 solvents. Crystallization of 3c from toluene:tetrahydrofuran mixtures provided single crystals of the solvent separated ion pair complex [Li(THF)4] [Mo2(Me)2(μ-Me){μ-HC(NDipp)2}2] (4c), where Dipp stands for 2,6-iPr2C6H3. A computational analysis of the Mo2(μ-Me)2Li core of complexes 3a and 3b has been developed, which is consistent with a small but non-negligible electron-density sharing between the C and Li atoms of the mainly ionic CH3···Li interactions.

  6. Biological effects of short-term, high-concentration exposure to methyl isocyanate. II. Blood chemistry and hematologic evaluations

    SciTech Connect

    Troup, C.M.; Dodd, D.E.; Fowler, E.H.; Frank, F.R.

    1987-06-01

    Human, rat, and guinea pig packed erythrocytes exposed to 100, 500, or 1000 ppm of methyl isocyanate (MIC) vapor in vitro showed a concentration-related inhibition of cholinesterase (ChE) activity. Rat and guinea pig packed erythrocytes showed an almost complete inhibition of ChE activity at 2000 ppm. In vitro exposures of human and guinea pig blood to 1000 or 2000 ppm of MIC vapor resulted in qualitative alterations in the electrophoretic mobility of hemoglobin (Hb) as measured by citrated agar electrophoresis. In rats and guinea pigs, neither IV injection of liquid MIC nor in vivo exposure to 1000 ppm of MIC by inhalation resulted in any inhibition of erythrocyte ChE activity or alteration in Hb electrophoretic mobility. As a result of these observations, it was concluded that neither ChE inhibition nor structural alteration of Hb were major contributing factors to death resulting from MIC exposure. Rats and guinea pigs receiving IV injections of liquid MIC showed an increase in creatine kinase (CK) levels. This increase could not be attributed to a specific isoenzyme of CK by ion exchange chromatography. Rats exposed to 100, 600, or 1000 ppm of MIC and guinea pigs exposed to 25, 125, or 225 ppm of MIC and bled immediately following a 15-min exposure or at 1, 2, 4, or 16 hr postexposure had the following alterations in blood parameters: (a) an increase in CK, (b) increases in hemoglobin concentration and hematocrit, (c) reticulocytosis (rats only), (d) neutrophilia, (e) a decrease in blood pH and PO/sub 2/, and (f) an increase in blood PCO/sub 2/. These findings indicate the occurrence of generalized hypoxic injury with concomitant pathophysiologic alterations, e.g., increases in hemoglobin and hematocrit concentrations.

  7. Bis(di­methyl­formamide)­penta­kis­(μ-N,2-dioxido­benzene-1-carb­ox­imidato)tetra­kis­(1-methyl­imidazole)di-μ-propionato-penta­manganese(III)manganese(II)–di­methyl­formamide–methanol (1/0.24/1.36)

    PubMed Central

    Lutter, Jacob C.; Kampf, Jeff W.; Zeller, Matthias; Zaleski, Curtis M.

    2013-01-01

    The title compound [Mn6(C7H4NO3)5(C3H5O2)2(C4H6N2)4.17(C3H7NO)1.83]·0.24C3H7NO·1.36CH3OH or Mn(II)(C3H5O2)2[15-MCMn(III)N(shi)-5](Me—Im)4.17(DMF)1.83·0.24DMF·1.36MeOH (where MC is metallacrown, shi3− is salicyl­hydroximate, Me—Im is 1-methyl­imidazole, DMF is N,N-di­methyl­formamide, and MeOH is methanol), contains an MnII ion in the central cavity and five MnIII ions in the MC ring. The central MnII ion is seven coordinate and has a geometry best described as distorted face-capped trigonal prismatic with Φ angles of 6.13, 10.36, and 11.73° and an estimated average s/h ratio of 1.03±0.11. Four of the ring MnIII ions are six coordinate with distorted octa­hedral geometries. Two of the MnIII ions have Λ absolute stereoconfiguration, while the other two MnIII ions have a planar configuration. The fifth MnIII ion is five coordinate and has a distorted square pyramidal geometry with τ = 0.20. Three of the MnIII ions bind one 1-methyl­imidazole ligand. Two of the ring MnIII ions have a 1-methyl­imidazole and a DMF disordered over a coordination site. For one of the ring MnIII ions, the occupancy ratio of the ligands refines to 0.51 (1):0.49 (1) in favor of the DMF. For the other ring MnIII ion, the occupancy ratio of the ligands refines to 0.68 (1):0.32 (1) in favor of the 1-methyl­imidazole. Two propionate anions serve to bridge the central MnII ion between two different MnIII ions. The methyl groups of the bridging propionate anions are disordered over two positions. The methyl group disorder also induces disorder in the H atoms of the adjacent methyl­ene C atom to the same degree. For one of the propionate anions, the occupancy ratio refines to 0.752 (8):0.248 (8) and for the second, the occupancy ratio refines to 0.604 (6):0.396 (6). In addition, the disorder of the methyl group of the latter propionate anion is correlated with a partially occupied [0.604 (6)] methanol mol­ecule. Furthermore, a methanol mol­ecule and a DMF

  8. Biconvex intraocular lenses and Nd:YAG capsulotomy: Experimental comparison of surface damage with different poly(methyl methacrylate) formulations

    SciTech Connect

    Downing, J.E.; Alberhasky, M.T. )

    1990-11-01

    Biconvex posterior chamber lenses have optical advantages and decrease the risk of capsular opacification, but they are more likely to be pitted during ND:YAG capsulotomy because of apposition of the lens to the capsule. This study reports the likelihood of surface damage to different formulations of poly(methyl methacrylate) at the energy levels required to open posterior capsules. Molded lenses are more easily damaged than higher molecular weight lathe-cut materials (P less than .01), as expected. However, by keeping energy output low, even injection-molded lenses showed minimal damage, with mean pit size 39 +/- 39 microns at 1 mJ. By using a converging contact lens, low power, and keeping the focus behind the capsule, damage to all materials tested should be clinically insignificant.

  9. Bis[O-methyl (4-eth-oxy-phen-yl)dithio-phospho-nato-κ(2) S,S']nickel(II).

    PubMed

    Sewpersad, Shirveen; Omondi, Bernard; Van Zyl, Werner E

    2012-12-01

    In the title compound, [Ni(C9H12O2PS2)2], the Ni(II) atom resides on an inversion center and is coordinated by four S atoms [Ni-S = 2.2328 (4) and 2.2455 (3) Å] in a distorted square-planar geometry [S-Ni-S = 88.443 (13) and 91.557 (13)°]. In the crystal, mol-ecules related by translation in [110] are linked into chains via weak C-H⋯O inter-actions. The crystal packing exhibits short inter-molecular S⋯S contacts of 3.3366 (5) Å. PMID:23468706

  10. EXPERIMENTAL EVALUATION OF CHEMICAL SEQUESTRATION OF CARBON DIOXIDE IN DEEP AQUIFER MEDIA - PHASE II

    SciTech Connect

    Neeraj Gupta; Bruce Sass; Jennifer Ickes

    2000-11-28

    In 1998 Battelle was selected by the U.S. Department of Energy's (DOE) National Energy Technology Laboratory (NETL) under a Novel Concepts project grant to continue Phase II research on the feasibility of carbon dioxide (CO{sub 2}) sequestration in deep saline formations. The focus of this investigation is to conduct detailed laboratory experiments to examine factors that may affect chemical sequestration of CO{sub 2} in deep saline formations. Reactions between sandstone and other geologic media from potential host reservoirs, brine solutions, and CO{sub 2} are being investigated under high-pressure conditions. Some experiments also include sulfur dioxide (SO{sub 2}) gases to evaluate the potential for co-injection of CO{sub 2} and SO{sub 2} related gases in the deep formations. In addition, an assessment of engineering and economic aspects is being conducted. This current Technical Progress Report describes the status of the project as of September 2000. The major activities undertaken during the quarter included several experiments conducted to investigate the effects of pressure, temperature, time, and brine composition on rock samples from potential host reservoirs. Samples (both powder and slab) were taken from the Mt. Simon Sandstone, a potential CO{sub 2} host formation in the Ohio, the Eau Claire Shale, and Rome Dolomite samples that form the caprock for Mt. Simon Sandstone. Also, a sample with high calcium plagioclase content from Frio Formation in Texas was used. In addition, mineral samples for relatively pure Anorthite and glauconite were experimented on with and without the presence of additional clay minerals such as kaolinite and montmorillonite. The experiments were run for one to two months at pressures similar to deep reservoirs and temperatures set at 50 C or 150 C. Several enhancements were made to the experimental equipment to allow for mixing of reactants and to improve sample collection methods. The resulting fluids (gases and liquids) as

  11. The Interstellar Abundance of Lead: Experimental Oscillator Strengths for Pb II λ1203 and λ1433 and New Detections of Pb II in the Interstellar Medium

    NASA Astrophysics Data System (ADS)

    Ritchey, Adam Michael; Heidarian, Negar; Irving, Richard E.; Federman, Steven R.; Ellis, David G.; Cheng, Song; Curtis, Larry J.; Furman, W. A.

    2015-08-01

    Accurate gas-phase abundances of ions in the interstellar medium may be obtained through the analysis of interstellar absorption lines, but only if the oscillator strengths (f-values) of the relevant transitions are well known. For dominant ions, comparison of the gas-phase abundance with the appropriate solar reference abundance yields the degree to which the element is incorporated into interstellar dust grains. Singly-ionized lead is the dominant form of this element in the neutral interstellar medium. However, while Pb II has several strong resonance lines in the ultraviolet, the f-values for these transitions are uncertain. Here, we present the first experimentally determined oscillator strengths for the Pb II transitions at 1203.6 Å and 1433.9 Å, obtained from lifetime measurements made using beam-foil techniques. We also present new detections of these lines in the interstellar medium from an analysis of archival spectra acquired by the Space Telescope Imaging Spectrograph onboard the Hubble Space Telescope. Notably, our observations of the Pb II λ1203 line represent the first detection of this transition in interstellar gas. Our experimental f-values for the Pb II λ1203 and λ1433 transitions are consistent with recent theoretical results, including our own relativistic calculations, but are significantly smaller than previous values based on older calculations. For the Pb II λ1433 line, in particular, our new f-value yields an increase in the interstellar abundance of Pb of 0.43 dex over estimates based on the f-value listed by Morton. With our revised f-values, and with our new detections of Pb II λ1203 and λ1433, we find that the depletion of Pb onto interstellar grains is not nearly as severe as previously thought, and is very similar to the depletions seen for elements such as Zn and Sn, which have similar condensation temperatures.

  12. Diaqua­bis(4-methyl­amino­benzoato-κO)bis­(nicotinamide-κN 1)nickel(II)

    PubMed Central

    Hökelek, Tuncer; Dal, Hakan; Tercan, Barış; Aybirdi, Özgür; Necefoğlu, Hacali

    2009-01-01

    The title NiII complex, [Ni(C8H8NO2)2(C6H6N2O)2(H2O)2], is centrosymmetric with the Ni atom on an inversion center. The mol­ecule contains two 4-methyl­amino­benzoate (MAB) and two nicotinamide (NA) ligands and two coordinated water mol­ecules, all ligands being monodentate. The four O atoms in the equatorial plane around the Ni atom form a slightly distorted square-planar arrangement, while the slightly distorted octa­hedral coordination is completed by the two N atoms of the NA ligands in the axial positions. The dihedral angle between the carboxyl­ate group and the adjacent benzene ring is 2.09 (14)°, while the pyridine and benzene rings are oriented at a dihedral angle of 66.15 (4)°. In the crystal structure, inter­molecular O—H⋯O and N—H⋯O hydrogen bonds link the mol­ecules into a three-dimensional network. PMID:21583824

  13. Selective electrocatalytic oxidation of a re-methyl complex to methanol by a surface-bound Ru(II) polypyridyl catalyst.

    PubMed

    Coggins, Michael K; Méndez, Manuel A; Concepcion, Javier J; Periana, Roy A; Meyer, Thomas J

    2014-11-12

    The complex [Ru(Mebimpy)(4,4'-((HO)2OPCH2)2bpy)(OH2)](2+) surface bound to tin-doped indium oxide mesoporous nanoparticle film electrodes (nanoITO-Ru(II)(OH2)(2+)) is an electrocatalyst for the selective oxidation of methylrhenium trioxide (MTO) to methanol in acidic aqueous solution. Oxidative activation of the catalyst to nanoITO-Ru(IV)(OH)(3+) induces oxidation of MTO. The reaction is first order in MTO with rate saturation observed at [MTO] > 12 mM with a limiting rate constant of k = 25 s(-1). Methanol is formed selectively in 87% Faradaic yield in controlled potential electrolyses at 1.3 V vs NHE. At higher potentials, oxidation of MTO by nanoITO-Ru(V)(O)(3+) leads to multiple electrolysis products. The results of an electrochemical kinetics study point to a mechanism in which surface oxidation to nanoITO-Ru(IV)(OH)(3+) is followed by direct insertion into the rhenium-methyl bond of MTO with a detectable intermediate. PMID:25325162

  14. Di-μ-hydroxido-bis-[hemiaqua-(N,N,N',N'-tetra-methyl-ethane-1,2-diamine)-copper(II)] bis-(tetra-fluoridoborate).

    PubMed

    Haníková, Jaroslava; Kuchár, Juraj; Trávníček, Zdeněk; Cernák, Juraj

    2012-06-01

    The title compound, [Cu(2)(OH)(2)(C(6)H(16)N(2))(2)(H(2)O)](BF(4))(2), consists of dinuclear centrosymmetric [Cu(2)(OH)(2)(tmen)(2)(H(2)O)](2+) complex cations (tmen = N,N,N',N'-tetra-methyl-ethane-1,2-diamine) and tetra-fluoridoborate anions. In the cation, the Cu(II) atom shows a slightly distorted square-pyramidal coordination geometry provided by a pair of μ-OH(-) anions and by the N atoms of a chelate tmen ligand in the basal plane. The apical position is statistically occupied by the O atom of a half-occupancy water mol-ecule. The F atoms of the anion are disordered over three sets of sites with occupancies of 0.598 (9):0.269 (6):0.134 (8). The crystal packing is governed by ionic forces as well as by O-H⋯F hydrogen bonds. PMID:22719335

  15. Aqua­(4-methyl­quinoline-κN)[N-(2-oxidobenzyl­idene)glycinato-κ3 O,N,O′]copper(II) hemihydrate

    PubMed Central

    Trávníček, Zdeněk; Marek, Jaromír; Vančo, Ján; Švajlenová, Oľga

    2008-01-01

    The title complex, [Cu(C9H7NO3)(C10H9N)(H2O)]·0.5H2O, crystallizes with two independent formula units in the asymmetric unit; the solvent mol­ecule is located on a twofold axis of symmetry. The CuII atom is coordinated by one tridentate N-salicylideneglycinate Schiff base ligand, one 4-methyl­quinoline ligand and one water mol­ecule, leading to a slightly distorted square-pyramidal N2O3 geometry. In the crystal structure, the mol­ecules are linked by O—H⋯O hydrogen bonds into linear chains in the [100] direction. The structure is further stabilized by inter­molecular C—H⋯O inter­actions and C⋯C contacts with C⋯C = 3.3058 (2), 3.3636 (2) and 3.3946 (2) Å. PMID:21201263

  16. Experimental and theoretical electron density study of a highly twisted polycyclic aromatic hydrocarbon: 4-methyl-[4]helicene.

    PubMed

    Wolstenholme, David J; Matta, Chérif F; Cameron, T Stanley

    2007-09-13

    Helicenes are molecules of considerable interest in view of their aromaticity which persists despite a marked departure from planarity and because of the extreme potency of some of their metabolites as tumor and mutation promoters. In this study, the electron density of 4-methyl-[4]helicene (or 4-methylbenzo[c]phenanthrene) is studied topologically with an emphasis on the fjord region since this region is where metabolic activation is initiated. The molecule consists of four fused aromatic rings that assume a twisted geometry. This geometry brings two hydrogen atoms into close proximity in the fjord region of the molecule accompanied by the appearance of an intramolecular C-Hdelta+...delta+H-C bond path (an interaction termed hydrogen-hydrogen or H- H bonding to distinguish it from dihydrogen bonding from which it is qualitatively distinct). In addition to the intramolecular H-H interaction, a number of intermolecular interactions are shown to be involved in the packing of this molecule in the crystalline state. The effect of the nonplanarity of the molecule on the local aromaticity of each ring is also discussed.

  17. Experimental studies on poly methyl methacrylate based gel polymer electrolytes for application in electrical double layer capacitors

    NASA Astrophysics Data System (ADS)

    Hashmi, S. A.; Kumar, Ashok; Tripathi, S. K.

    2007-11-01

    Studies have been carried out on gel polymer electrolytes comprising poly methyl methacrylate (PMMA)-ethylene carbonate (EC)-propylene carbonate (PC)-salts, LiClO4, NaClO4 and (C2H5)4NClO4 (TEAClO4) with a view to using them as electrolytes in electrical double layer capacitors (EDLCs) based on activated charcoal powder electrodes. The optimum composition of gel electrolytes, PMMA (20 wt%)-EC : PC (1 : 1 v/v)-1.0 M salts exhibit high ionic conductivity of the order of ~10-3 S cm-1 at room temperature with good mechanical/dimensional stability, suitable for their application in EDLCs. The EDLCs have been characterized using linear sweep cyclic voltammetry, galvanostatic charge-discharge tests and ac impedance spectroscopy. The values of capacitance of 68-151 mF cm-2 (equivalent to single electrode specific capacitance of 38-78 Fg-1 of activated charcoal powder) have been observed. These values correspond to a specific energy of 5.3-10.8 Wh kg-1 and a power density of 0.19-0.22 kW kg-1. The capacitance values have been observed to be stable up to 5000 voltammetric cycles or even more. A comparison of studies shows the predominant role of anions of the gel electrolytes in the capacitive behaviour of EDLCs.

  18. Analysis of Experimental Data for High Burnup PWR Spent Fuel Isotopic Validation - Vandellos II Reactor

    SciTech Connect

    Ilas, Germina; Gauld, Ian C

    2011-01-01

    This report is one of the several recent NUREG/CR reports documenting benchmark-quality radiochemical assay data and the use of the data to validate computer code predictions of isotopic composition for spent nuclear fuel, to establish the uncertainty and bias associated with code predictions. The experimental data analyzed in the current report were acquired from a high-burnup fuel program coordinated by Spanish organizations. The measurements included extensive actinide and fission product data of importance to spent fuel safety applications, including burnup credit, decay heat, and radiation source terms. Six unique spent fuel samples from three uranium oxide fuel rods were analyzed. The fuel rods had a 4.5 wt % {sup 235}U initial enrichment and were irradiated in the Vandellos II pressurized water reactor operated in Spain. The burnups of the fuel samples range from 42 to 78 GWd/MTU. The measurements were used to validate the two-dimensional depletion sequence TRITON in the SCALE computer code system.

  19. Changes and significance of IL-25 in chicken collagen II-induced experimental arthritis (CIA).

    PubMed

    Kaiwen, Wang; Zhaoliang, Su; Yinxia, Zhao; Siamak, Sandoghchian Shotorbani; Zhijun, Jiao; Yuan, Xue; Heng, Yang; Dong, Zheng; Yanfang, Liu; Pei, Shen; Shengjun, Wang; Qixiang, Shao; Xinxiang, Huang; Liwei, Lu; Huaxi, Xu

    2012-08-01

    Rheumatoid arthritis (RA) is an autoimmune inflammatory disease. It is a systemic inflammatory disease, characterized by chronic, symmetrical, multi-articular synovial arthritis. IL-25 (IL-17E) is a member of the recently emerged cytokine family (IL-17s), which is expressed in Th2 cells and bone marrow-derived mast cells. Unlike the other members of this family, IL-25 is capable of inducing Th2-associated cytokines (IL-4, IL-5, and IL-13) and also promotes the release of some pro-immune factors (IL-6 and IL-8). IL-25 is also a pleiotropic factor, which constitutes a tissue-specific pathological injury and chronic inflammation. In this study, we used chicken collagen II-induced experimental arthritis (CIA) model in DBA/1 mice to investigate the relationship between IL-25 and other inflammatory factors, revealing the possible mechanism in CIA. Our results showed that the expression level of IL-25 was enhanced in the late stage of CIA, and IL-17 was increased in the early stage of the disease. It is well known that IL-17 has a crucial role in the development of RA pathogenesis, and IL-25 plays a significant role in humoral immune. For reasons given above, we suggested that the IL-25 inhibited IL-17 expression to some extent, while enhancing the production of IL-4. It was confirmed that IL-25 not only regulated the cellular immune, but also involved the humoral immune in rheumatoid arthritis.

  20. Sex Differences in Learned Helplessness: II. The Contingencies of Evaluative Feedback in the Classroom and III. An Experimental Analysis.

    ERIC Educational Resources Information Center

    Dweck, Carol S.; And Others

    1978-01-01

    In Study I, teachers' work-related feedback to boys and girls was observed in a classroom situation. In Study II, the different contingencies of work-related criticism observed for boys and girls in the first study were programed in an experimental situation and the children's attributions for failure feedback were assessed. (JMB)

  1. Final Safety Analysis Addenda to Hazards Summary Report, Experimental Breeder Reactor II (EBR-II): upgrading of plant protection system. Volume II

    SciTech Connect

    Allen, N. L.; Keeton, J. M.; Sackett, J. I.

    1980-06-01

    This report is the second in a series of compilations of the formal Final Safety Analysis Addenda (FSAA`s) to the EBR-II Hazard Summary Report and Addendum. Sections 2 and 3 are edited versions of the original FSAA`s prepared in support of certain modifications to the reactor-shutdown-system portion of the EBR-II plant-protection system. Section 4 is an edited version of the original FSAA prepared in support of certain modifications to a system classified as an engineered safety feature. These sections describe the pre- and postmodification system, the rationale for the modification, and required supporting safety analysis. Section 5 provides an updated description and analysis of the EBR-II emergency power system. Section 6 summarizes all significant modifications to the EBR-II plant-protection system to date.

  2. An experimental comparison of the Marcus-Hush and Butler-Volmer descriptions of electrode kinetics applied to cyclic voltammetry. The one electron reductions of europium (III) and 2-methyl-2-nitropropane studied at a mercury microhemisphere electrode

    NASA Astrophysics Data System (ADS)

    Henstridge, Martin C.; Wang, Yijun; Limon-Petersen, Juan G.; Laborda, Eduardo; Compton, Richard G.

    2011-11-01

    We present a comparative experimental evaluation of the Butler-Volmer and Marcus-Hush models using cyclic voltammetry at a microelectrode. Numerical simulations are used to fit experimental voltammetry of the one electron reductions of europium (III) and 2-methyl-2-nitropropane, in water and acetonitrile, respectively, at a mercury microhemisphere electrode. For Eu (III) very accurate fits to experiment were obtained over a wide range of scan rates using Butler-Volmer kinetics, whereas the Marcus-Hush model was less accurate. The reduction of 2-methyl-2-nitropropane was well simulated by both models, however Marcus-Hush required a reorganisation energy lower than expected.

  3. Methylation matters

    PubMed Central

    Costello, J.; Plass, C.

    2001-01-01

    DNA methylation is not just for basic scientists any more. There is a growing awareness in the medical field that having the correct pattern of genomic methylation is essential for healthy cells and organs. If methylation patterns are not properly established or maintained, disorders as diverse as mental retardation, immune deficiency, and sporadic or inherited cancers may follow. Through inappropriate silencing of growth regulating genes and simultaneous destabilisation of whole chromosomes, methylation defects help create a chaotic state from which cancer cells evolve. Methylation defects are present in cells before the onset of obvious malignancy and therefore cannot be explained simply as a consequence of a deregulated cancer cell. Researchers are now able to detect with exquisite sensitivity the cells harbouring methylation defects, sometimes months or years before the time when cancer is clinically detectable. Furthermore, aberrant methylation of specific genes has been directly linked with the tumour response to chemotherapy and patient survival. Advances in our ability to observe the methylation status of the entire cancer cell genome have led us to the unmistakable conclusion that methylation abnormalities are far more prevalent than expected. This methylomics approach permits the integration of an ever growing repertoire of methylation defects with the genetic alterations catalogued from tumours over the past two decades. Here we discuss the current knowledge of DNA methylation in normal cells and disease states, and how this relates directly to our current understanding of the mechanisms by which tumours arise.


Keywords: methylation; cancer PMID:11333864

  4. Synthesis, spectral, antitumor, antioxidant and antimicrobial studies on Cu(II), Ni(II) and Co(II) complexes of 4-[(1H-Benzoimidazol-2-ylimino)-methyl]-benzene-1,3-diol

    NASA Astrophysics Data System (ADS)

    El-wakiel, Nadia; El-keiy, Mai; Gaber, Mohamed

    2015-08-01

    A new Schiff base of 2-aminobenzimidazole with 2,4-dihydroybezaldehyde (H3L), and its Cu(II), Ni(II) and Co(II) complexes have been synthesized and characterized by elemental analyses, molar conductance, thermal analysis (TGA), inductive coupled plasma (ICP), magnetic moment measurements, IR, EI-mass, UV-Vis. and ESR spectral studies. On the basis of spectral studies and analytical data, it is evident that the Schiff base acts as dibasic tridentate ligand coordinating via deprotonated OH, NH and azomethine nitrogen atom. The results showed that Co(II) and Ni(II) complexes have tetrahedral structure while Cu(II) complexes has octahedral geometry. The kinetic and thermodynamic parameters of the thermal decomposition stages have been evaluated. The studied complexes were tested for their in vitro antimicrobial activities against some bacterial strains. The anticancer activity of the ligand and its metal complexes is evaluated against human liver Carcinoma (HEPG2) cell. These compounds exhibited a moderate and weak activity against the tested HEPG2 cell lines with IC50 of 9.08, 18.2 and 19.7 μg/ml for ligand, Cu(II) and Ni(II) complexes, respectively. In vitro antioxidant activity of the newly synthesized compounds has also been evaluated.

  5. Asymmetric Synthesis of Chiral α-Methyl-α,β-diamino Acid Derivatives via Group-Assisted Purification Chemistry Using N-Phosphonyl Imines and a Ni(II)-Complexed Alanine Schiff Base.

    PubMed

    Zhang, Haowei; Yang, Bing; Yang, Zhen; Lu, Hongjian; Li, Guigen

    2016-09-01

    The Mannich reaction between chiral N-phosphonyl imines and a Ni(II)-complexed alanine Schiff base (Ala-Ni) is reported. With a chiral phosphonyl auxiliary, a single isomer of α-methyl-α,β-diamino acid derivative containing vicinal chiral centers, including a chiral quaternary carbon center, can be obtained simply by washing the crude mixture with cosolvents. The absolute stereochemistry of the enantiomerically pure product has been unambiguously determined by X-ray crystallographic analysis. PMID:27459278

  6. The Role of Gastrodin on Hippocampal Neurons after N-Methyl-D-Aspartate Excitotoxicity and Experimental Temporal Lobe Seizures.

    PubMed

    Wong, Shi-Bing; Hung, Wei-Chen; Min, Ming-Yuan

    2016-06-30

    Tian ma (Gastrodia elata, GE) is an ancient Chinese herbal medicine that has been suggested to be effective as an anticonvulsant and analgesic, and to have sedative effects against vertigo, general paralysis, epilepsy and tetanus. The primary active ingredient isolated from GE is termed gastrodin, which is the glucoside of 4-hydroxybenzyl alcohol (4-HBA). Gastrodin can abolish hypoxia-, glutamate- and N-methyl-D-aspartate (NMDA) receptor-induced toxicity in primary culture of rat cortical neurons, and reduces seizure severity in seizure-sensitive gerbils. We evaluated the effect of gastrodin on NMDA excitotoxicity in hippocampal slice cultures (HSCs) with propidium iodide (PI) fluorescence measurement. We also evaluated the effects of gastrodin for treating active in vivo temporal lobe seizures induced by lithium/pilocarpine. Seizure severity, time span to seizure onset, mortality rate and hippocampal histology for survivors were compared. The effect of gastrodin was evaluated for treating in vitro seizures induced by Mg²⁺-free medium in hippocampal slices. Frequencies and amplitudes of epileptiform discharges were compared. The effect of gastrodin on synaptic transmission was evaluated on hippocampal CA1 Schaffer collaterals. Application of 25 μM gastrodin significantly suppressed NMDA excitotoxicity in CA3 but not in CA1 hippocampus and dentate gyrus. Intraventricular gastrodin accelerated seizure onset for 12 min after intraperitoneal pilocarpine injection (P = 0.051). Three of five rats (60%) in the gastrodin group, and three of four (75%) in the dimethyl sulfoxide (DMSO) group died within 3 days after status epilepticus (SE). Gastrodin also failed to inhibit epileptiform discharges in hippocampal slices induced by Mg²⁺-free medium, believed to be NMDA receptor-mediated spontaneous activity. The frequencies of the spontaneous epileptiform discharges were similar under treatments with 25 μM gastrodin, 200 μM gastrodin and DMSO. For the evaluation of

  7. Experimental and theoretical approaches for Cd(II) biosorption from aqueous solution using Oryza sativa biomass.

    PubMed

    Fawzy, Manal; Nasr, Mahmoud; Helmi, Shacker; Nagy, Heba

    2016-11-01

    Biomass of Oryza sativa (OS) was tested for the removal of Cd(II) ions from synthetic and real wastewater samples. Batch experiments were conducted to investigate the effects of operating parameters on Cd(II) biosorption. Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive x-ray spectroscopy were used to examine the surface characteristics of the Cd(II)-loaded biomass. The maximum removal efficiency of Cd(II) was 89.4% at optimum pH 6.0, biosorbent dose 10.0 g L(-1), initial Cd(II) 50 mg L(-1), and biosorbent particle size 0.5 mm. The applicability of Langmuir and Freundlich isotherms to the sorbent system implied the existence of both monolayer and heterogeneous surface conditions. Kinetic studies revealed that the adsorption process of Cd(II) followed the pseudo-second-order model (r2: 0.99). On the theoretical side, an adaptive neuro-fuzzy inference system (ANFIS) was applied to select the operating parameter that mostly influences the Cd(II) biosorption process. Results from ANFIS indicated that pH was the most influential parameter affecting Cd(II) removal efficiency, indicating that the biomass of OS was strongly pH sensitive. Finally, the biomass was confirmed to adsorb Cd(II) from real wastewater samples with removal efficiency close to 100%. However, feasibility studies of such systems on a large-scale application remain to be investigated.

  8. Experimental Study Of SHEFEX II Hypersonic Aerodynamics And Canard Efficiency In H2K

    NASA Astrophysics Data System (ADS)

    Neeb, D.; Gulhan, A.

    2011-05-01

    One main objective of the DLR SHEFEX programme is to prove that sharp edged vehicles are capable of performing a re-entry into earth atmosphere by using a simple thermal protection system consisting of flat ceramic tiles. In comparison to blunt nose configurations like the Space shuttle, which are normally used for re-entry configurations, the SHEFEX TPS design is able to significantly reduce the costs and complexity of TPS structures and simultaneously increase the aerodynamic performance of the flight vehicle [1], [2]. To study its characteristics and perform several defined in-flight experiments during re-entry, the vehicle’s attitude will be controlled actively by canards [3]. In the framework of the SHEFEX II project an experimental investigation has been conducted in the hypersonic wind tunnel H2K to characterize the aerodynamic performance of the vehicle in hypersonic flow regime. The model has a modular design to enable the study of a variety of different influencing parameters. Its 4 circumferential canards have been made independently adjustable to account for the simulation of different manoeuvre conditions. To study the control behaviour of the vehicle and validate CFD data, a variation of canard deflections, angle of attack and angle of sideslip have been applied. Tests have been carried out at Mach 7 and 8.7 with a Reynolds number sensitivity study at the lower Mach number. The model was equipped with a six component internal balance to realize accurate coefficient measurements. The flow topology has been analyzed using Schlieren images. Beside general aerodynamic performance and canard efficiencies, flow phenomena like shock impingement on the canards could be determined by Schlieren images as well as by the derived coefficients.

  9. Numerical and experimental analysis of factors leading to suture dehiscence after Billroth II gastric resection.

    PubMed

    Cvetkovic, Aleksandar M; Milasinovic, Danko Z; Peulic, Aleksandar S; Mijailovic, Nikola V; Filipovic, Nenad D; Zdravkovic, Nebojsa D

    2014-11-01

    The main goal of this study was to numerically quantify risk of duodenal stump blowout after Billroth II (BII) gastric resection. Our hypothesis was that the geometry of the reconstructed tract after BII resection is one of the key factors that can lead to duodenal dehiscence. We used computational fluid dynamics (CFD) with finite element (FE) simulations of various models of BII reconstructed gastrointestinal (GI) tract, as well as non-perfused, ex vivo, porcine experimental models. As main geometrical parameters for FE postoperative models we have used duodenal stump length and inclination between gastric remnant and duodenal stump. Virtual gastric resection was performed on each of 3D FE models based on multislice Computer Tomography (CT) DICOM. According to our computer simulation the difference between maximal duodenal stump pressures for models with most and least preferable geometry of reconstructed GI tract is about 30%. We compared the resulting postoperative duodenal pressure from computer simulations with duodenal stump dehiscence pressure from the experiment. Pressure at duodenal stump after BII resection obtained by computer simulation is 4-5 times lower than the dehiscence pressure according to our experiment on isolated bowel segment. Our conclusion is that if the surgery is performed technically correct, geometry variations of the reconstructed GI tract by themselves are not sufficient to cause duodenal stump blowout. Pressure that develops in the duodenal stump after BII resection using omega loop, only in the conjunction with other risk factors can cause duodenal dehiscence. Increased duodenal pressure after BII resection is risk factor. Hence we recommend the routine use of Roux en Y anastomosis as a safer solution in terms of resulting intraluminal pressure. However, if the surgeon decides to perform BII reconstruction, results obtained with this methodology can be valuable. PMID:25201585

  10. Curcumin attenuates arsenic-induced hepatic injuries and oxidative stress in experimental mice through activation of Nrf2 pathway, promotion of arsenic methylation and urinary excretion.

    PubMed

    Gao, Shuang; Duan, Xiaoxu; Wang, Xin; Dong, Dandan; Liu, Dan; Li, Xin; Sun, Guifan; Li, Bing

    2013-09-01

    Oxidative stress is one of the major mechanisms implicated in inorganic arsenic poisoning. Curcumin is a natural phenolic compound with impressive antioxidant properties. What's more, curcumin is recently proved to exert its chemopreventive effects partly through the activation of nuclear factor (erythroid-2 related) factor 2 (Nrf2) and its antioxidant and phase II detoxifying enzymes. In vivo, we investigated the protective effects of curcumin against arsenic-induced hepatotoxicity and oxidative injuries. Our results showed that arsenic-induced elevation of serum alanine amino transferase (ALT) and aspartate aminotransferase (AST) activities, augmentation of hepatic malonaldehyde (MDA), as well as the reduction of blood and hepatic glutathione (GSH) levels, were all consistently relieved by curcumin. We also observed the involvement of curcumin in promoting arsenic methylation and urinary elimination in vivo. Furthermore, both the hepatic Nrf2 protein and two typically recognized Nrf2 downstream genes, NADP(H) quinine oxidoreductase 1 (NQO1) and heme oxygenase-1 (HO-1), were consistently up-regulated in curcumin-treated mice. Our study confirmed the antagonistic roles of curcumin to counteract inorganic arsenic-induced hepatic toxicity in vivo, and suggested that the potent Nrf2 activation capability might be valuable for the protective effects of curcumin against arsenic intoxication. This provides a potential useful chemopreventive dietary component for human populations. PMID:23871787

  11. Curcumin attenuates arsenic-induced hepatic injuries and oxidative stress in experimental mice through activation of Nrf2 pathway, promotion of arsenic methylation and urinary excretion.

    PubMed

    Gao, Shuang; Duan, Xiaoxu; Wang, Xin; Dong, Dandan; Liu, Dan; Li, Xin; Sun, Guifan; Li, Bing

    2013-09-01

    Oxidative stress is one of the major mechanisms implicated in inorganic arsenic poisoning. Curcumin is a natural phenolic compound with impressive antioxidant properties. What's more, curcumin is recently proved to exert its chemopreventive effects partly through the activation of nuclear factor (erythroid-2 related) factor 2 (Nrf2) and its antioxidant and phase II detoxifying enzymes. In vivo, we investigated the protective effects of curcumin against arsenic-induced hepatotoxicity and oxidative injuries. Our results showed that arsenic-induced elevation of serum alanine amino transferase (ALT) and aspartate aminotransferase (AST) activities, augmentation of hepatic malonaldehyde (MDA), as well as the reduction of blood and hepatic glutathione (GSH) levels, were all consistently relieved by curcumin. We also observed the involvement of curcumin in promoting arsenic methylation and urinary elimination in vivo. Furthermore, both the hepatic Nrf2 protein and two typically recognized Nrf2 downstream genes, NADP(H) quinine oxidoreductase 1 (NQO1) and heme oxygenase-1 (HO-1), were consistently up-regulated in curcumin-treated mice. Our study confirmed the antagonistic roles of curcumin to counteract inorganic arsenic-induced hepatic toxicity in vivo, and suggested that the potent Nrf2 activation capability might be valuable for the protective effects of curcumin against arsenic intoxication. This provides a potential useful chemopreventive dietary component for human populations.

  12. Detrimental effects of N(omega) nitro-L-arginine methyl ester (L-NAME)in experimental Escherichia coli sepsis in the newborn piglet.

    PubMed

    Kim, Sung Shin; Hwang, Jong Hee; Choi, Chang Won; Shim, Jae Won; Chang, Yun Sil; Park, Won Soon; Oh, Chang Kyu

    2003-10-01

    The role of nitric oxide during neonatal sepsis is complex. We tested the hypothesis that nonselective inhibition of nitric oxide synthase with N(omega) -nitro-L-arginine methyl ester (L-NAME) is detrimental during the early phase of experimental sepsis in the newborn piglet. Newborn piglets were divided into four groups: 6 in the control group, 6 in the L-NAME control group, 12 in the sepsis group (SG), and 11 in the sepsis with L-NAME group (NS). Sepsis was induced by intravenous injection of 10(8) colony forming units of Escherichia coli. L-NAME 10 mg/kg was given intravenously 60 min before the induction of sepsis. The survival rate of piglets after 4 hr was 27% in NS, while it was 100% in other groups. Systemic hypotension, observed in both SG and NS, were more profound in NS. Leukopenia was observed in both SG and NS. Thrombocytopenia, prolongation of prothrombin time and activated partial thromboplastin time, and increase in thrombin-antithrombin complexes were observed only in NS. Decreased PaO2 /FiO2 ratio, arterial pH and base excess, and increased blood lactate levels observed in both SG and NS, but were more profound in NS. These findings suggest that nonselective inhibition of nitric oxide synthase with L-NAME is detrimental during the early phase of experimental neonatal sepsis.

  13. Ni(II), Pd(II) and Pt(II) complexes of (1H-1,2,4-triazole-3-ylimino)methyl]naphthalene-2-ol. Structural, spectroscopic, biological, cytotoxicity, antioxidant and DNA binding

    NASA Astrophysics Data System (ADS)

    Gaber, M.; El-Ghamry, H. A.; Fathalla, S. K.

    2015-03-01

    Metal complexes of the general formula [ML(H2O)Cl]nH2O; n = 1 for M = Ni and Pt and n = 2 for M = Pd, L = Schiff base (HL) derived from the condensation of 3-amino-1,2,4-triazole and 2-hydroxy-1-naphthaldehyde, were prepared. The synthesized ligand and its metal complexes were characterized on the basis of elemental analyses, spectral and magnetic studies as well as thermal analysis. The IR spectra revealed that the ligand is coordinated to the metal ions in bidentate manner via the N-atom of the azomethine group and the phenolic OH group. Square planar geometry was proposed for Pd(II) and Pt(II) complexes and tetrahedral for Ni(II) complex. The ligand and its metal complexes were screened against the sensitive organisms Escherichia coli as Gram-negative bacteria, Staphylococcus aureus as Gram-positive bacteria, Aspergillus flavus and Candida albicans as fungi. Moreover, the anticancer activity of the ligand and its metal complexes was evaluated in liver carcinoma (HEPG2) cell line. The results obtained indicated that the Schiff base ligand is more effective than its metal complexes towards the tested cell line. Ni(II), Pd(II) and Pt(II) complexes as well as the free Schiff base ligand were tested for their antioxidant activities. The DNA-binding properties of the studied complexes have been investigated by electronic absorption and viscosity measurements.

  14. Ni(II), Pd(II) and Pt(II) complexes of (1H-1,2,4-triazole-3-ylimino)methyl]naphthalene-2-ol. Structural, spectroscopic, biological, cytotoxicity, antioxidant and DNA binding.

    PubMed

    Gaber, M; El-Ghamry, H A; Fathalla, S K

    2015-03-15

    Metal complexes of the general formula [ML(H2O)Cl]nH2O; n=1 for M=Ni and Pt and n=2 for M=Pd, L=Schiff base (HL) derived from the condensation of 3-amino-1,2,4-triazole and 2-hydroxy-1-naphthaldehyde, were prepared. The synthesized ligand and its metal complexes were characterized on the basis of elemental analyses, spectral and magnetic studies as well as thermal analysis. The IR spectra revealed that the ligand is coordinated to the metal ions in bidentate manner via the N-atom of the azomethine group and the phenolic OH group. Square planar geometry was proposed for Pd(II) and Pt(II) complexes and tetrahedral for Ni(II) complex. The ligand and its metal complexes were screened against the sensitive organisms Escherichia coli as Gram-negative bacteria, Staphylococcus aureus as Gram-positive bacteria, Aspergillus flavus and Candida albicans as fungi. Moreover, the anticancer activity of the ligand and its metal complexes was evaluated in liver carcinoma (HEPG2) cell line. The results obtained indicated that the Schiff base ligand is more effective than its metal complexes towards the tested cell line. Ni(II), Pd(II) and Pt(II) complexes as well as the free Schiff base ligand were tested for their antioxidant activities. The DNA-binding properties of the studied complexes have been investigated by electronic absorption and viscosity measurements. PMID:25576936

  15. Refining the Experimental Analysis of Academic Skills Deficits: Part II. Use of Brief Experimental Analysis to Evaluate Reading Fluency Treatments

    ERIC Educational Resources Information Center

    Daly, Edward J., III; Bonfiglio, Christine M.; Mattson, Tara; Persampieri, Michael; Foreman-Yates, Kristin

    2006-01-01

    The technology of brief experimental analysis is just beginning to be used for identification of effective treatments for individual students who experience difficulty with oral reading fluency. In this study, the effect of a reading fluency treatment package was examined on easy and hard passages, and generalization was assessed on passages with…

  16. Crystal structure of bis­(di­methyl­ammonium) hexa­aqua­cobalt(II) bis­(sulfate) dihydrate

    PubMed Central

    Held, Peter

    2015-01-01

    The title salt, (C2H8N)2[Co(H2O)6)](SO4)2·2H2O, is isotypic with (C2H8N)2[Ni(H2O)6)](SO4)2·2H2O. The Co—O bond lengths in the [Co(H2O)6]2+ complex cation show very similar distances as in the related Tutton salt (NH4)2[Co(H2O)6)](SO4)2 [average 2.093 (17) Å], but are significantly longer than in the isotypic NiII compound (Δd ≃ 0.04 Å). The cobalt cation reaches an overall bond-valence sum of 1.97 valence units. The S—O distances are nearly equal, ranging from 1.454 (4) to 1.470 (3) Å [mean 1.465 (12) Å]; however, the O—S—O angles vary clearly from 108.1 (2) to 110.2 (2)° [average bond angle 109.5 (9)°]. The non-coordinating water mol­ecules and di­methyl­ammonium cations connect the sulfate tetrahedra and the [Co(H2O)6]2+ octa­hedron via O—H⋯O and N—H⋯O hydrogen bonds of weak up to medium strength into a three-dimensional framework whereby the complex metal cations and sulfate anions are arranged in sheets parallel to (001). PMID:26029410

  17. Experimental and DFT characterization, antioxidant and anticancer activities of a Cu(II)-irbesartan complex: structure-antihypertensive activity relationships in Cu(II)-sartan complexes.

    PubMed

    Islas, María S; Luengo, Alicia; Franca, Carlos A; Merino, Mercedes Griera; Calleros, Laura; Rodriguez-Puyol, Manuel; Lezama, Luis; Ferrer, Evelina G; Williams, Patricia A M

    2016-10-01

    The coordination compound of the antihypertensive ligand irbesartan (irb) with copper(II) (CuIrb) was synthesized and characterized by FTIR, FT-Raman, UV-visible, reflectance and EPR spectroscopies. Experimental evidence allowed the implementation of structural and vibrational studies by theoretical calculations made in the light of the density functional theory (DFT). This compound was designed to induce structural modifications on the ligand. No antioxidant effects were displayed by both compounds, though CuIrb behaved as a weak 1,1-diphenyl-2-picrylhydrazyl radical (DPPH(·)) scavenger (IC50 = 425 μM). The measurements of the contractile capacity on human mesangial cell lines showed that CuIrb improved the antihypertensive effects of the parent medication. In vitro cell growth inhibition against prostate cancer cell lines (LNCaP and DU 145) was measured for CuIrb, irbesartan and copper(II). These cell lines have been selected since the angiotensin II type 1 (AT1) receptor (that was blocked by the angiotensin receptor blockers, ARB) has been identified in them. The complex exerted anticancer behavior (at 100 μM) improving the activity of the ligand. Flow cytometry determinations were used to determine late apoptotic mechanisms of cell death. Experimental and DFT characterization of an irbesartan copper(II) complex has been performed. The complex exhibits low scavenging activity against DPPH(·) and significant growth inhibition of LNCaP and DU 145 prostate cancer cell lines. Flow cytometry determinations were used to determine late apoptotic mechanisms of cell death. This compound improved the antihypertensive effect of irbesartan. This effect was observed earlier for the mononuclear Cu-candesartan complex, but not in structurally modified sartans forming dinuclear or octanuclear Cu-sartan compounds.

  18. Simulations for experimental study of warm dense matter and inertial fusion energy applications on NDCX-II

    SciTech Connect

    Barnard, J J; Armijo, J; Bieniosek, F M; Friedman, A; Hay, M J; Henestroza, E; Logan, B G; More, R M; Ni, P A; Perkins, L J; Ng, S; Wurtele, J S; Yu, S S; Zylstra, A B

    2010-03-19

    The Neutralized Drift Compression Experiment II (NDCX II) is an induction accelerator planned for initial commissioning in 2012. The final design calls for a {approx}3 MeV, {approx}30 A Li{sup +} ion beam, delivered in a bunch with characteristic pulse duration of 1 ns, and transverse dimension of order 1 mm. The purpose of NDCX II is to carry out experimental studies of material in the warm dense matter regime, and ion beam/hydrodynamic coupling experiments relevant to heavy ion based inertial fusion energy. In preparation for this new machine, we have carried out hydrodynamic simulations of ion-beam-heated, metallic solid targets, connecting quantities related to observables, such as brightness temperature and expansion velocity at the critical frequency, with the simulated fluid density, temperature, and velocity. We examine how these quantities depend on two commonly used equations of state.

  19. Simulations for experimental study of warm dense matter and inertial fusion energy applications on NDCX-II

    SciTech Connect

    Barnard, J.J.; Armijo, J.; Bieniosek, F.M.; Friedman, A.; Hay, M.; Henestroza, E.; Logan, B.G.; More, R.M.; Ni, P.A.; Perkins, L. J.; Ng, S-F.; Wurtele, J.S.; Yu, S.S.; Zylstra, A.B.

    2009-09-01

    The Neutralized Drift Compression Experiment II (NDCX II) is an induction accelerator planned for initial commissioning in 2012. The final design calls for a {approx}3 MeV, {approx}30 A Li{sup +} ion beam, delivered in a bunch with characteristic pulse duration of 1 ns, and ransverse dimension of order 1 mm. The purpose of NDCX II is to carry out experimental studies of material in the warm dense matter regime, and ion beam/hydrodynamic coupling experiments relevant to heavy ion based inertial fusion energy. In preparation for this new machine, we have carried out hydrodynamic simulations of ion-beam-heated, metallic solid targets, connecting quantities related to observables, such as brightness temperature and expansion velocity at the critical frequency, with the simulated fluid density, temperature, and velocity. We examine how these quantities depend on two commonly used equations of state.

  20. Experimental and theoretical approaches for Cd(II) biosorption from aqueous solution using Oryza sativa biomass.

    PubMed

    Fawzy, Manal; Nasr, Mahmoud; Helmi, Shacker; Nagy, Heba

    2016-11-01

    Biomass of Oryza sativa (OS) was tested for the removal of Cd(II) ions from synthetic and real wastewater samples. Batch experiments were conducted to investigate the effects of operating parameters on Cd(II) biosorption. Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive x-ray spectroscopy were used to examine the surface characteristics of the Cd(II)-loaded biomass. The maximum removal efficiency of Cd(II) was 89.4% at optimum pH 6.0, biosorbent dose 10.0 g L(-1), initial Cd(II) 50 mg L(-1), and biosorbent particle size 0.5 mm. The applicability of Langmuir and Freundlich isotherms to the sorbent system implied the existence of both monolayer and heterogeneous surface conditions. Kinetic studies revealed that the adsorption process of Cd(II) followed the pseudo-second-order model (r2: 0.99). On the theoretical side, an adaptive neuro-fuzzy inference system (ANFIS) was applied to select the operating parameter that mostly influences the Cd(II) biosorption process. Results from ANFIS indicated that pH was the most influential parameter affecting Cd(II) removal efficiency, indicating that the biomass of OS was strongly pH sensitive. Finally, the biomass was confirmed to adsorb Cd(II) from real wastewater samples with removal efficiency close to 100%. However, feasibility studies of such systems on a large-scale application remain to be investigated. PMID:27185086

  1. Experimental and theoretical study on free 5-nitroquinoline, 5-nitroisoquinoline, and their zinc(II) halide complexes.

    PubMed

    Yurdakul, Senay; Badoğlu, Serdar; Güleşci, Yeliz

    2015-02-25

    In this study where the interpretations of the experimental IR and Raman spectra recorded at room temperature for the ligands 5-nitroquinoline (5NQ) and 5-nitroisoquinoline (5NIQ) and also for their Zn(II) halide (halogen: chlorine, bromine, iodine) complexes were first reported, the assignments of the observed fundamental bands were achieved in the light of the vibrational spectral data and total energy distribution (TED) values calculated at B3LYP/6-311++G(d,p) and B3LYP/LANL2DZ levels of theory. The equilibrium geometrical parameters, Natural Bond Orbital (NBO) charges and frontier orbital (HOMO, LUMO) energies of these molecular structures were also calculated at the same level of theory. Comparisons over the corresponding experimental and theoretical data obtained for the title ligands and their complexes revealed that in complex form both ligands bond to Zn(II) ion through their ring nitrogen atoms and NO2 groups at the same time. PMID:25282024

  2. Filtrates & Residues: Experimental Work with Tin (II) Chloride in a High School.

    ERIC Educational Resources Information Center

    Sanchez, Manuela Martin

    1988-01-01

    Presents a high school chemistry lab experiment using tin (II) chloride to explore the concepts of hydrolysis, Le Chatelier's principle, and electrolysis. Presents methodology and the chemistry involved. Offers questions for the students. (MVL)

  3. DETECTORS AND EXPERIMENTAL METHODS: Online measurement of the BEPC II background using RadFET dosimeters

    NASA Astrophysics Data System (ADS)

    Gong, Hui; Li, Jin; Gong, Guang-Hua; Li, Yu-Xiong; Hou, Lei; Shao, Bei-Bei

    2009-09-01

    To monitor the integral dose deposited in the BESIII electromagnetic calorimeter whose performance degrades due to exposure to the BEPC II background, a 400 nm IMPL RadFET dosimeter-based integral dose online monitor system is built. After calibration with the 60Co source and verification with TLD in the pulse radiation fields, an experiment was arranged to measure the BEPC II background online. The results are presented.

  4. Interplay of LNA and 2'-O-methyl RNA in the structure and thermodynamics of RNA hybrid systems: a molecular dynamics study using the revised AMBER force field and comparison with experimental results.

    PubMed

    Yildirim, Ilyas; Kierzek, Elzbieta; Kierzek, Ryszard; Schatz, George C

    2014-12-11

    LNA and 2'-O-methyl RNA residues have C3'-endo sugar puckering, structurally LNA residues have a frozen sugar backbone which provides entropic enhancement of stabilities while the 2'-O-methyl RNA residues are more flexible and maintain base stacking that is almost untouched compared to RNA. Thus, enhancement of the structural stabilities of RNA duplexes by 2'-O-methyl RNA modifications is smaller than for the corresponding LNA modifications. Indeed, our experimental measurements show that on average each 2'-O-methyl RNA and LNA substitution in a RNA duplex enhances duplex stability by 0.2 and 1.4 kcal/mol, respectively. Our computational binding free energy predictions are qualitatively in line with these results. The only exception is for the full 2'-O-methyl RNA duplex, which is overstabilized, implying that further force field revisions are needed. Collectively, the results presented in this paper explain the atomistic details of the structural and thermodynamic roles of LNA and 2'-O-methyl RNA residues in RNA hybrid duplexes, shedding light on the mechanism behind targeting endogenous micro RNA (miRNA) in order to regulate mRNA activity and inhibit gene expression in the cell.

  5. Crystal structure of bis­(1-methyl-1H-imidazole-κN 3)(5,10,15,20-tetra­phenyl­porphyrinato-κ4 N)iron(II)–1-methyl-1H-imidazole (1/2)

    PubMed Central

    Guan, Ye; Powell, Douglas R.; Richter-Addo, George B.

    2015-01-01

    The title compound, [Fe(C44H28N4)(C4H6N2)2]·2C4H6N2, is a six-coordinate FeII–porphyrinate complex with the metal located on a center of inversion and coordinated by two axial 1-methyl­imidazole ligands; the complex crystallizes as a 1-methyl­imidazole disolvate. The 1-methyl­imidazole group bonded to the FeII atom [occupancy ratio 0.789 (4):0.211 (4)] and the unbound 1-methyl­imidazole mol­ecule [0.519 (4):0.481 (4)] were disordered. The average Fe—N(porphyrinate) bond length is 1.998 (3) Å and the axial Fe—N(imidazole) bond length is 1.9970 (12) Å. In the crystal, mol­ecules are linked into a three-mol­ecule aggregate by two weak C—H⋯N inter­actions. PMID:25844207

  6. Experimental and theoretical studies on the inclusion complexation of syringic acid with alpha-, beta-, gamma- and heptakis(2,6-di-O-methyl)-beta-cyclodextrin.

    PubMed

    Song, Le Xin; Wang, Hai Ming; Xu, Peng; Yang, Yan; Zhang, Zi Qiang

    2008-04-01

    Intermolecular interactions of alpha-, beta-, gamma- and heptakis(2,6-di-O-methyl)-beta-cyclodextrin (CD) with syringic acid (Syr) in aqueous solution are investigated by fluorescence spectroscopy. The fluorescence intensity of Syr gradually increases with the addition of the CDs. The formation constants (K) of the host-guest inclusion complexes are determined using a nonlinear analysis. The association abilities of Syr with the CDs decrease in the order gamma->beta->alpha- approximately DMbeta-CD. Both the intrinsic binding abilities of the CDs and the structural effect of Syr are taken into consideration when comparing the K values. Based on the results of NMR experimental and theoretical PM3 calculations both in vacuo and in water, it is found that Syr stays near the wider rim of alpha-CD cavity. Both the number of substituted groups (NSG) in a guest and the molar volume ratio of the guest to host cavity (MVR) play an important role in forming the CD supramolecular complexes of a homologous series of phenol derivatives, such as 2-methoxylphenol (2-Mop), eugenol (Eug) and Syr, i.e., an appropriate NSG or MVR in an inclusion system, such as in 2-Mop-alpha-CD, Eug-beta-CD and Syr-gamma-CD systems, can maximize the intermolecular interaction between host and guest.

  7. Synthesis, structural, spectroscopic studies, NBO analysis, NLO and HOMO-LUMO of 4-methyl-N-(3-nitrophenyl)benzene sulfonamide with experimental and theoretical approaches.

    PubMed

    Sarojini, K; Krishnan, H; Kanakam, Charles C; Muthu, S

    2013-05-01

    The sulfonamide compound, 4-methyl-N-(3-nitrophenyl)benzene sulfonamide (abbreviated as 4M3NPBS) has been synthesized and characterized by FTIR, FT-Raman NMR, single crystal X-ray diffraction and thermal analysis. Density functional (DFT) calculations have been carried out for the title compound by performing DFT level of theory using B3LYP/6-31G(d,p) basis set. The calculated results show that the predicted geometry can well reproduce the structural parameters. Predicted vibrational frequencies have been assigned and compared with the experimental IR spectra and they support each other. The UV-Vis spectrum of the compound was recorded. The theoretical electronic absorption spectra have been calculated by using CIS, TD-DFT, ZINDO methods. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The first order hyperpolarizability (β0) of 4M3NPBS was calculated using B3LYP/6-31G(d,p) method on the basis of finite-field approach. In addition, frontier molecular orbitals and molecular electrostatic potential were carried out by using density functional theory (DFT/B3LYP) 6-31G(d,p) basis set. The calculated HOMO and LUMO energies show that charge transfer occur in the molecule. The thermal stability of the title compound was determined with the aid of thermo gravimetric analysis (TGA) and differential thermal analysis (DTA).

  8. Synthesis, structural, spectroscopic studies, NBO analysis, NLO and HOMO-LUMO of 4-methyl-N-(3-nitrophenyl)benzene sulfonamide with experimental and theoretical approaches

    NASA Astrophysics Data System (ADS)

    Sarojini, K.; Krishnan, H.; Kanakam, Charles C.; Muthu, S.

    2013-05-01

    The sulfonamide compound, 4-methyl-N-(3-nitrophenyl)benzene sulfonamide (abbreviated as 4M3NPBS) has been synthesized and characterized by FTIR, FT-Raman NMR, single crystal X-ray diffraction and thermal analysis. Density functional (DFT) calculations have been carried out for the title compound by performing DFT level of theory using B3LYP/6-31G(d,p) basis set. The calculated results show that the predicted geometry can well reproduce the structural parameters. Predicted vibrational frequencies have been assigned and compared with the experimental IR spectra and they support each other. The UV-Vis spectrum of the compound was recorded. The theoretical electronic absorption spectra have been calculated by using CIS, TD-DFT, ZINDO methods. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The first order hyperpolarizability (β0) of 4M3NPBS was calculated using B3LYP/6-31G(d,p) method on the basis of finite-field approach. In addition, frontier molecular orbitals and molecular electrostatic potential were carried out by using density functional theory (DFT/B3LYP) 6-31G(d,p) basis set. The calculated HOMO and LUMO energies show that charge transfer occur in the molecule. The thermal stability of the title compound was determined with the aid of thermo gravimetric analysis (TGA) and differential thermal analysis (DTA).

  9. Anti-inflammatory Effect of Methyl Gallate on Experimental Arthritis: Inhibition of Neutrophil Recruitment, Production of Inflammatory Mediators, and Activation of Macrophages.

    PubMed

    Correa, Luana Barbosa; Pádua, Tatiana Almeida; Seito, Leonardo Noboru; Costa, Thadeu Estevam Moreira Maramaldo; Silva, Magaiver Andrade; Candéa, André Luis Peixoto; Rosas, Elaine Cruz; Henriques, Maria G

    2016-06-24

    Methyl gallate (MG) is a prevalent phenolic acid in the plant kingdom, and its presence in herbal medicines might be related to its remarkable biological effects, such as its antioxidant, antitumor, and antimicrobial activities. Although some indirect evidence suggests anti-inflammatory activity for MG, there are no studies demonstrating this effect in animal models. Herein, we demonstrated that MG (0.7-70 mg/kg) inhibited zymosan-induced experimental arthritis in a dose-dependent manner. The oral administration of MG (7 mg/kg) attenuates arthritis induced by zymosan, affecting edema formation, leukocyte migration, and the production of inflammatory mediators (IL-1β, IL-6, TNF-α, CXCL-1, LTB4, and PGE2). Pretreatment with MG inhibited in vitro neutrophil chemotaxis elicited by CXCL-1, as well as the adhesion of these cells to TNF-α-primed endothelial cells. MG also impaired zymosan-stimulated macrophages by inhibiting IL-6 and NO production, COX-2 and iNOS expression, and intracellular calcium mobilization. Thus, MG is likely to present an anti-inflammatory effect by targeting multiple cellular events such as the production of various inflammatory mediators, as well as leukocyte activation and migration. PMID:27227459

  10. Synthesis, structural, spectroscopic studies, NBO analysis, NLO and HOMO-LUMO of 4-methyl-N-(3-nitrophenyl)benzene sulfonamide with experimental and theoretical approaches.

    PubMed

    Sarojini, K; Krishnan, H; Kanakam, Charles C; Muthu, S

    2013-05-01

    The sulfonamide compound, 4-methyl-N-(3-nitrophenyl)benzene sulfonamide (abbreviated as 4M3NPBS) has been synthesized and characterized by FTIR, FT-Raman NMR, single crystal X-ray diffraction and thermal analysis. Density functional (DFT) calculations have been carried out for the title compound by performing DFT level of theory using B3LYP/6-31G(d,p) basis set. The calculated results show that the predicted geometry can well reproduce the structural parameters. Predicted vibrational frequencies have been assigned and compared with the experimental IR spectra and they support each other. The UV-Vis spectrum of the compound was recorded. The theoretical electronic absorption spectra have been calculated by using CIS, TD-DFT, ZINDO methods. Stability of the molecule arising from hyper conjugative interactions, charge delocalization has been analyzed using natural bond orbital (NBO) analysis. The first order hyperpolarizability (β0) of 4M3NPBS was calculated using B3LYP/6-31G(d,p) method on the basis of finite-field approach. In addition, frontier molecular orbitals and molecular electrostatic potential were carried out by using density functional theory (DFT/B3LYP) 6-31G(d,p) basis set. The calculated HOMO and LUMO energies show that charge transfer occur in the molecule. The thermal stability of the title compound was determined with the aid of thermo gravimetric analysis (TGA) and differential thermal analysis (DTA). PMID:23466326

  11. Computer Simulations to Study Diffraction Effects of Stacking Faults in Beta-SiC: II. Experimental Verification. 2; Experimental Verification

    NASA Technical Reports Server (NTRS)

    Pujar, Vijay V.; Cawley, James D.; Levine, S. (Technical Monitor)

    2000-01-01

    Earlier results from computer simulation studies suggest a correlation between the spatial distribution of stacking errors in the Beta-SiC structure and features observed in X-ray diffraction patterns of the material. Reported here are experimental results obtained from two types of nominally Beta-SiC specimens, which yield distinct XRD data. These samples were analyzed using high resolution transmission electron microscopy (HRTEM) and the stacking error distribution was directly determined. The HRTEM results compare well to those deduced by matching the XRD data with simulated spectra, confirming the hypothesis that the XRD data is indicative not only of the presence and density of stacking errors, but also that it can yield information regarding their distribution. In addition, the stacking error population in both specimens is related to their synthesis conditions and it appears that it is similar to the relation developed by others to explain the formation of the corresponding polytypes.

  12. Methyl Iodide

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Methyl iodide (MeI, iodomethane, CH3I) was reported as a potential alternative to the stratospheric ozone-depleting fumigant methyl bromide (MeBr) in the mid-1990s (Sims et al., 1995; Ohr et al., 1996). It has since received significant research attention to determine its environmental fate and tran...

  13. Mercury methylation rates of biofilm and plankton microorganisms from a hydroelectric reservoir in French Guiana.

    PubMed

    Huguet, L; Castelle, S; Schäfer, J; Blanc, G; Maury-Brachet, R; Reynouard, C; Jorand, F

    2010-02-15

    The Petit-Saut ecosystem is a hydroelectric reservoir covering 365km(2) of flooded tropical forest. This reservoir and the Sinnamary Estuary downstream of the dam are subject to significant mercury methylation. The mercury methylation potential of plankton and biofilm microorganisms/components from different depths in the anoxic reservoir water column and from two different sites along the estuary was assessed. For this, reservoir water and samples of epiphytic biofilms from the trunk of a submerged tree in the anoxic water column and from submerged branches in the estuary were batch-incubated from 1h to 3 months with a nominal 1000ng/L spike of Hg(II) chloride enriched in (199)Hg. Methylation rates were determined for different reservoir and estuarine communities under natural nutrient (reservoir water, estuary freshwater) and artificial nutrient (culture medium) conditions. Methylation rates in reservoir water incubations were the highest with plankton microorganisms sampled at -9.5m depth (0.5%/d) without addition of biofilm components. Mercury methylation rates of incubated biofilm components were strongly enhanced by nutrient addition. The results suggested that plankton microorganisms strongly contribute to the total Hg methylation in the Petit-Saut reservoir and in the Sinnamary Estuary. Moreover, specific methylation efficiencies (%Me(199)Hg(net)/cell) suggested that plankton microorganisms could be more efficient methylating actors than biofilm consortia and that their methylation efficiency may be reduced in the presence of biofilm components. Extrapolation to the reservoir scale of the experimentally determined preliminary methylation efficiencies suggested that plankton microorganisms in the anoxic water column could produce up to 27mol MeHg/year. Taking into account that (i) demethylation probably occurs in the reservoir and (ii) that the presence of biofilm components may limit the methylation efficiency of plankton microorganisms, this result is

  14. Theoretical and experimental studies of Cu(II) and Zn(II) coordination compounds with N,O donor bidentate Schiff base ligand containing amino phenol moiety

    NASA Astrophysics Data System (ADS)

    Kusmariya, Brajendra S.; Tiwari, Anjali; Mishra, A. P.; Naikoo, Gowhar Ahmad

    2016-09-01

    We report here two mononuclear Cu(II) and Zn(II) coordination compounds of general formula [CuII(L)2].2H2O (1) and [ZnII(L)2].3H2O (2) derived from bidentate 2-chloro-6-{[(4-hydroxy-3-methoxyphenyl)methylidene]amino}-4 nitrophenol ligand (HL). These compounds were synthesized and characterized by elemental analysis, FT-IR, uv-vis, 1H NMR, molar conductance, thermal, PXRD, SEM-EDX and electrochemical studies. The PXRD and SEM analysis shows the amorphous/nanocrystalline nature of 1 and crystalline nature of 2. The diffraction peak broadening was explained in terms of domain size and the crystallite lattice strain. Thermogravimetric analysis in the range of 300-1172 K has been performed to determine the thermal stability of synthesized compounds. The non-isothermal kinetic parameters of degradation process were calculated using Coats-Redfern (C-R), Piloyan-Novikova (P-N) and Horowitz-Metzger (H-M) methods assuming first order degradation and proposed a random nucleation mechanism of thermal decomposition for both compounds. The cyclic voltammetric studies reveal the irreversibility of the oxidation/reduction process of synthesized compounds. To support the experimental findings theoretical calculations by means of DFT and TD-DFT at B3LYP level were incorporated. In addition; frequency calculations, HOMO-LUMO, energy gap (ΔE), molecular electrostatic potential (MEP), spin density and crystal packing were also computed at the same level of theory.

  15. Experimental and Computational Evidence for the Reduction Mechanisms of Aromatic N-oxides by Aqueous Fe(II)-Tiron Complex.

    PubMed

    Chen, Yiling; Dong, Hao; Zhang, Huichun

    2016-01-01

    A combined experimental-theoretical approach was taken to elucidate the reduction mechanisms of five representative aromatic N-oxides (ANOs) by Fe(II)-tiron complex and to identify the rate-limiting step. Based on the possible types of complexes formed with the reductant, three groups of ANOs were studied: type I refers to those forming 5-membered ring complexes through the N and O atoms on the side chain; type II refers to those forming 6-membered ring complexes through the N-oxide O atom and the O atom on the side chain; and type III refers to complexation through the N-oxide O atom only. Density functional theory calculations suggested that the elementary reactions, including protonation, N-O bond cleavage, and the second electron transfer processes, are barrierless, indicating that the first electron transfer is rate-limiting. Consistent with the theoretical results, the experimental solvent isotope effect, KIEH, for the reduction of quinoline N-oxide (a type III ANO) was obtained to be 1.072 ± 0.025, suggesting protonation was not involved in the rate-limiting step. The measured nitrogen kinetic isotope effect, KIEN, for the reduction of pyridine N-oxide (a type III ANO) (1.022 ± 0.006) is in good agreement with the calculated KIEN for its first electron transfer (1.011-1.028), confirming that the first electron transfer is rate-limiting. Electrochemical cell experiments demonstrated that the electron transfer process can be facilitated significantly by type I complexation with FeL2(6-) (1:2 Fe(II)-tiron complex), to some extent by type II complexation with free Fe(II), but not by weak type III complexation.

  16. Atomic resolution experimental phase information reveals extensive disorder and bound 2-methyl-2,4-pentanediol in Ca 2+ -calmodulin

    SciTech Connect

    Lin, Jiusheng; van den Bedem, Henry; Brunger, Axel T.; Wilson, Mark A.

    2016-01-01

    Calmodulin (CaM) is the primary calcium signaling protein in eukaryotes and has been extensively studied using various biophysical techniques. Prior crystal structures have noted the presence of ambiguous electron density in both hydrophobic binding pockets of Ca2+-CaM, but no assignment of these features has been made. In addition, Ca2+-CaM samples many conformational substates in the crystal and accurately modeling the full range of this functionally important disorder is challenging. In order to characterize these features in a minimally biased manner, a 1.0 Å resolution single-wavelength anomalous diffraction data set was measured for selenomethionine-substituted Ca2+-CaM. Density-modified electron-density maps enabled the accurate assignment of Ca2+-CaM main-chain and side-chain disorder. These experimental maps also substantiate complex disorder models that were automatically built using low-contour features of model-phased electron density. Furthermore, experimental electron-density maps reveal that 2-methyl-2,4-pentanediol (MPD) is present in the C-terminal domain, mediates a lattice contact between N-terminal domains and may occupy the N-terminal binding pocket. The majority of the crystal structures of target-free Ca2+-CaM have been derived from crystals grown using MPD as a precipitant, and thus MPD is likely to be bound in functionally critical regions of Ca2+-CaM in most of these structures. The adventitious binding of MPD helps to explain differences between the Ca2+-CaM crystal and solution structures and is likely to favor more open conformations of the EF-hands in the crystal.

  17. Experimental Study of Combustion and Emissions Characteristics of Methyl Oleate, as a Surrogate for Biodiesel, in a Direct injection Diesel Engine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study evaluates the combustion and emissions characteristics of methyl oleate (C19H36O2 CAS# 112-62) produced by transesterification from oleic acid, one of the main fatty acid components of biodiesel. The ignition delay of ultra-low sulfur diesel#2 (ULSD) and its blends with methyl oleate (O20...

  18. Methyl chloroform

    SciTech Connect

    Wray, T.K.

    1994-04-01

    Methyl chloroform is identified as a Class 1 ozone-depleting substance under Title VI of the CAA Amendments. On Nov. 30, 1993, EPA ordered the phaseout of Class 1 ozone-depleting substances -- chlorofluorocarbons (CFCs), halons, carbon tetrachloride and methyl chloroform -- by Jan. 1, 1996. Methyl chloroform and other Class 1 substances may be used after the dead-line if sources can be found through recycling or existing inventories. Methyl chloroform is listed as a hazardous air pollutant under CAA. It also is a SARA Title III, Sec. 313 compound with a reportable quantity of 1,000 pounds. OSHA and the American Conference of Government Industrial Hygienists have set 350 ppm as the time-weighted average airborne exposure level for methyl chloroform. NIOSH lists its immediately dangerous to life or health'' concentration as 1,000 parts per million. DOT identifies the substance as a hazardous material, Class 6.1 (poison).

  19. Crystal structure, spectroscopic properties and DFT studies on copper (II) complex of bis{(E)-1-[(2-phenoxyphenylimino)methyl]naphthalene-2-ol}chloroform solvate

    NASA Astrophysics Data System (ADS)

    Macit, Mustafa; Alpaslan, Gökhan

    2014-08-01

    Copper (II) complex of the title Schiff base compound was synthesized from the reaction of 2-hydroxy-1-naphthaldehyde with 2-phenoxyaniline. The complex has been characterized by FT-IR, and X-ray single-crystal techniques. The molecular geometry, vibrational frequencies values of the compound in the ground state have been calculated using the density functional theory (DFT/B3LYP) method with the LANL2DZ basis set and compared with the experimental data. The calculated results show that the optimized geometry is compatible with the crystal structure and the theoretical vibrational frequencies are in good agreement with the experimental values. The energetic behavior of the compound in solvent media has been examined using B3LYP method with the LANL2DZ basis set by applying the polarizable continuum model (PCM). In addition, frontier molecular orbital analysis (HOMO-LUMO), natural bond orbital analysis (NBO) and non-linear optical (NLO) properties of the compound were investigated using same theoretical calculations.

  20. Investigation of the interactions between Pt(II) and Pd(II) derivatives of 5,10,15,20-tetrakis (N-methyl-4-pyridyl) porphyrin and G-quadruplex DNA.

    PubMed

    Sabharwal, Navin C; Mendoza, Oscar; Nicoludis, John M; Ruan, Thomas; Mergny, Jean-Louis; Yatsunyk, Liliya A

    2016-04-01

    G-quadruplexes are non-canonical DNA structures formed by guanine-rich DNA sequences that are implicated in cancer and aging. Understanding how small molecule ligands interact with quadruplexes is essential both to the development of novel anticancer therapeutics and to the design of new quadruplex-selective probes needed for elucidation of quadruplex biological functions. In this work, UV-visible, fluorescence, and circular dichroism spectroscopies, fluorescence resonance energy transfer (FRET) melting assays, and resonance light scattering were used to investigate how the Pt(II) and Pd(II) derivatives of the well-studied 5,10,15,20-tetrakis(N-methyl-4-pyridyl)porphyrin (TMPyP4) interact with quadruplexes formed by the human telomeric DNA, Tel22, and by the G-rich sequences from oncogene promoters. Our results suggest that Pt- and PdTMPyP4 interact with Tel22 via efficient π-π stacking with a binding affinity of 10(6)-10(7) M(-1). Under porphyrin excess, PtTMPyP4 aggregates using Tel22 as a template; the aggregates reach maximum size at [PtTMPyP4]/[Tel22] ~8 and dissolve at [PtTMPyP4]/[Tel22] ≤ 2. FRET assays reveal that both porphyrins are excellent stabilizers of human telomeric DNA, with stabilization temperature of 30.7 ± 0.6 °C for PtTMPyP4 and 30.9 ± 0.4 °C for PdTMPyP4 at [PtTMPyP4]/[Tel22] = 2 in K(+) buffer, values significantly higher as compared to those for TMPyP4. The porphyrins display modest selectivity for quadruplex vs. duplex DNA, with selectivity ratios of 150 and 330 for Pt- and PdTMPyP4, respectively. This selectivity was confirmed by observed 'light switch' effect: fluorescence of PtTMPyP4 increases significantly in the presence of a variety of DNA secondary structures, yet the strongest effect is produced by quadruplex DNA. PMID:26748794

  1. Horizontal transfer of DNA methylation patterns into bacterial chromosomes

    PubMed Central

    Shin, Jung-Eun; Lin, Chris; Lim, Han N.

    2016-01-01

    Horizontal gene transfer (HGT) is the non-inherited acquisition of novel DNA sequences. HGT is common and important in bacteria because it enables the rapid generation of new phenotypes such as antibiotic resistance. Here we show that in vivo and in vitro DNA methylation patterns can be horizontally transferred into bacterial chromosomes to program cell phenotypes. The experiments were performed using a synthetic system in Escherichia coli where different DNA methylation patterns within the cis-regulatory sequence of the agn43 gene turn on or off a fluorescent reporter (CFP). With this system we demonstrated that DNA methylation patterns not only accompany the horizontal transfer of genes into the bacterial cytoplasm but can be transferred into chromosomes by: (i) bacteriophage P1 transduction; and (ii) transformation of extracellular synthetic DNA. We also modified the experimental system by replacing CFP with the SgrS small RNA, which regulates glucose and methyl α-D-glucoside uptake, and showed that horizontally acquired DNA methylation patterns can increase or decrease cell fitness. That is, horizontally acquired DNA methylation patterns can result in the selection for and against cells that have HGT. Findings from these proof-of-concept experiments have applications in synthetic biology and potentially broad implications for bacterial adaptation and evolution. PMID:27084942

  2. Gas-phase reactions of aryl radicals with 2-butyne: experimental and theoretical investigation employing the N-methyl-pyridinium-4-yl radical cation.

    PubMed

    Lam, A K Y; Li, C; Khairallah, G; Kirk, B B; Blanksby, S J; Trevitt, A J; Wille, U; O'Hair, R A J; da Silva, G

    2012-02-21

    Aromatic radicals form in a variety of reacting gas-phase systems, where their molecular weight growth reactions with unsaturated hydrocarbons are of considerable importance. We have investigated the ion-molecule reaction of the aromatic distonic N-methyl-pyridinium-4-yl (NMP) radical cation with 2-butyne (CH(3)C≡CCH(3)) using ion trap mass spectrometry. Comparison is made to high-level ab initio energy surfaces for the reaction of NMP and for the neutral phenyl radical system. The NMP radical cation reacts rapidly with 2-butyne at ambient temperature, due to the apparent absence of any barrier. The activated vinyl radical adduct predominantly dissociates via loss of a H atom, with lesser amounts of CH(3) loss. High-resolution Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry allows us to identify small quantities of the collisionally deactivated reaction adduct. Statistical reaction rate theory calculations (master equation/RRKM theory) on the NMP+2-butyne system support our experimental findings, and indicate a mechanism that predominantly involves an allylic resonance-stabilized radical formed via H atom shuttling between the aromatic ring and the C(4) side-chain, followed by cyclization and/or low-energy H atom β-scission reactions. A similar mechanism is demonstrated for the neutral phenyl radical (Ph˙)+2-butyne reaction, forming products that include 3-methylindene. The collisionally deactivated reaction adduct is predicted to be quenched in the form of a resonance-stabilized methylphenylallyl radical. Experiments using a 2,5-dichloro substituted methyl-pyridiniumyl radical cation revealed that in this case CH(3) loss from the 2-butyne adduct is favoured over H atom loss, verifying the key role of ortho H atoms, and the shuttling mechanism, in the reactions of aromatic radicals with alkynes. As well as being useful phenyl radical analogues, pyridiniumyl radical cations may form in the ionosphere of Titan, where they could undergo rapid

  3. Dicarbon­yl(hexa­methyl­ene-1,3,5,7-tetra­mine-κN 1)(η5-penta­methyl­cyclo­penta­dien­yl)iron(II) tetra­fluoridoborate

    PubMed Central

    M’thiruaine, Cyprian M.; Friedrich, Holger B.; Changamu, Evans O.; Fernandes, Manuel A.

    2012-01-01

    In the title compound, [Fe(C10H15)(C6H12N4)(CO)2]BF4, the arrangement around the FeII atom corresponds to a three-legged piano stool. The penta­methyl­cyclo­penta­dienyl (Cp*) ligand occupies three coordination sites, while two CO ligands and one N atom of the hexa­methyl­ene­tetra­mine ligand occupy the remaining coordination sites, completing a pseudo-octahedral geometry. Both the complex cation and the BF4 − anion reside on crystallographic mirror planes. The Fe—N bond length is 2.069 (2) and the Fe—Cp*(centroid) distance is 1.7452 (3) Å. PMID:22807762

  4. Mustard gas and American race-based human experimentation in World War II.

    PubMed

    Smith, Susan L

    2008-01-01

    This essay examines the risks of racialized science as revealed in the American mustard gas experiments of World War II. In a climate of contested beliefs over the existence and meanings of racial differences, medical researchers examined the bodies of Japanese American, African American, and Puerto Rican soldiers for evidence of how they differed from whites. PMID:18840244

  5. An Experimental Evaluation of Hyperactivity and Food Additives. 1977-Phase II.

    ERIC Educational Resources Information Center

    Harley, J. Preston; And Others

    Phase II of a study on the effectiveness of B. Feingold's recommended diet for hyperactive children involved the nine children (mean age 9 years) who had shown the "best" response to diet manipulation in Phase I. Each child served as his own control and was challenged with specified amounts of placebo and artificial color containing food items…

  6. Phenyltrimethylammonium Salts as Methylation Reagents in the Nickel-Catalyzed Methylation of C-H Bonds.

    PubMed

    Uemura, Takeshi; Yamaguchi, Mao; Chatani, Naoto

    2016-02-24

    Methylation of C(sp(2))-H bonds was achieved through the Ni(II)-catalyzed reaction of benzamides with phenyltrimethylammonium bromide or iodide as the source of the methyl group. The reaction has a broad scope and shows high functional-group compatibility. The reaction is also applicable to the methylation of C(sp(3))-H bonds in aliphatic amides. PMID:26821872

  7. A new three-dimensional CdII supramolecular framework constructed from the 1-[(1H-tetrazol-5-yl)methyl]-1,4-diazoniabicyclo[2.2.2]octane ligand.

    PubMed

    Li, Qiang; Wang, Hui-Ting; Zhou, Lin

    2015-02-01

    A new tetrazole-metal supramolecular compound, di-μ-chlorido-bis(trichlorido{1-[(1H-tetrazol-5-yl-κN(2))methyl]-1,4-diazoniabicyclo[2.2.2]octane}cadmium(II)), [Cd2(C8H16N6)2Cl8], has been synthesized and structurally characterized by single-crystal X-ray diffraction. In the structure, each Cd(II) cation is coordinated by five Cl atoms (two bridging and three terminal) and by one N atom from the 1-[(1H-tetrazol-5-yl)methyl]-1,4-diazoniabicyclo[2.2.2]octane ligand, adopting a slightly distorted octahedral coordination geometry. The bridging bicyclo[2.2.2]octane and chloride ligands link the Cd(II) cations into one-dimensional ribbon-like N-H...Cl hydrogen-bonded chains along the b axis. An extensive hydrogen-bonding network formed by N-H...Cl and C-H...Cl hydrogen bonds, and interchain π-π stacking interactions between adjacent tetrazole rings, consolidate the crystal packing, linking the poymeric chains into a three-dimensional supramolecular network.

  8. Matter from Outside Our Solar System -- New Insights, Part II. Experimental Measurements and Interpretation.

    ERIC Educational Resources Information Center

    Wefel, John P.

    1982-01-01

    The second of two parts (part 1 in v20 n4, p222, Apr 1982) focuses on experimental techniques used to study cosmic-ray isotopic composition, experimental results, and comparison between cosmic-ray source matter and solar-system material. Several models for nucleosynthesis and evolution of cosmic-source matter are also discussed. (Author/JN)

  9. Crystal structure of cis,fac-{N,N-bis­[(pyridin-2-yl)meth­yl]methyl­amine-κ3 N,N′,N′′}di­chlorido­(dimethyl sulfoxide-κS)ruthenium(II)

    PubMed Central

    Trotter, Kasey; Arulsamy, Navamoney; Hulley, Elliott

    2015-01-01

    The reaction of di­chlorido­tetra­kis­(dimethyl sulfoxide)­ruthen­ium(II) with N,N-bis[(pyridin-2-yl)meth­yl]methyl­amine aff­ords the title complex, [RuCl2(C13H15N3)(C2H6OS)]. The asymmetric unit contains a well-ordered complex mol­ecule. The N,N-bis­[(pyridin-2-yl)meth­yl]methyl­amine (bpma) ligand binds the cation through its two pyridyl N atoms and one aliphatic N atom in a facial manner. The coordination sphere of the low-spin d 6 RuII is distorted octahedral. The dimethyl sulfoxide (dmso) ligand coordinates to the cation through its S atom and is cis to the aliphatic N atom. The two chloride ligands occupy the remaining sites. The bpma ligand is folded with the dihedral angle between the mean planes passing through its two pyridine rings being 64.55 (8)°. The two N—Ru—N bite angles of the ligand at 81.70 (7) and 82.34 (8)° illustrate the distorted octa­hedral coordination geometry of the RuII cation. Two neighboring molecules are weakly associated through mutual intermolecular hydrogen bonding involving the O atom and one of the methyl groups of the dmso ligand. One of the chloride ligands is also weakly hydrogen bonded to a pyridyl H atom of another molecule. PMID:26396870

  10. Fe(II)/Et3N-Relay-catalyzed domino reaction of isoxazoles with imidazolium salts in the synthesis of methyl 4-imidazolylpyrrole-2-carboxylates, its ylide and betaine derivatives

    PubMed Central

    Galenko, Ekaterina E; Tomashenko, Olesya A; Novikov, Mikhail S; Panikorovskii, Taras L

    2015-01-01

    Summary A simple approach was developed for the synthesis of methyl 4-imidazolylpyrrole-2-carboxylates from easily available compounds, 5-methoxyisoxazoles and phenacylimidazolium salts under hybrid Fe(II)/Et3N relay catalysis. The products were easily transformed into the corresponding 3-(5-methoxycarbonyl-1H-imidazol-3-ium-3-yl)pyrrol-1-ides, which in turn can be hydrolyzed under basic conditions into the corresponding betaines. A carbene tautomeric form of the 4-methoxycarbonyl-substituted imidazolylpyrrolides was trapped by reaction with sulfur affording the corresponding imidazolethiones under very mild conditions. PMID:26664593

  11. Pd(II)-catalyzed ligand controlled synthesis of methyl 1-benzyl-1H-indole-3-carboxylates and bis(1-benzyl-1H-indol-3-yl)methanones.

    PubMed

    Shen, Rong; Kusakabe, Taichi; Takahashi, Keisuke; Kato, Keisuke

    2014-07-14

    A simple change of ligand and solvent allows controlled, effective switching between cyclization-carbonylation and cyclization-carbonylation-cyclization-coupling (CCC-coupling) reactions of 2-alkynylanilines catalyzed by palladium(II). The use of a [Pd(tfa)2(box)] catalyst in iPrOH afforded symmetrical ketones bearing two indoles in good yields; replacing the catalyst and solvent with Pd(tfa)2 and DMSO-MeOH led to the formation of methyl 1-benzyl-1H-indole-3-carboxylates in good yields.

  12. Time constants and feedback transfer functions of EBR-II (Experimental Breeder Reactor) subassembly types

    SciTech Connect

    Grimm, K.N.; Meneghetti, D.

    1986-09-01

    Time constants, feedback reactivity transfer functions and power coefficients are calculated for stereotypical subassemblies in the EBR-II reactor. These quantities are calculated from nodal reactivities obtained from a reactor kinetic code analysis for a step change in power. Due to the multiplicity of eigenvalues, there are several time constants for each nodal position in a subassembly. Compared with these calculated values are analytically derived values for the initial node of a given channel.

  13. Experimental investigation of the landing characteristics of hypersonic flight vehicles (Saenger II/Horus)

    NASA Astrophysics Data System (ADS)

    Huenecke, Klaus; Mertens, Josef

    An experimental study of the landing characteristics of the Saenger concept for a two-stage, fully reusable space transport vehicle which takes off from a conventional runway and reaches earth orbit, is reported. The problem of maneuvering during reentry is reviewed, and the experimental program is summarized. The test results, which demonstrate the stability of the vehicle during reentry and landing, are reviewed and discussed.

  14. Prevention and Treatment of Experimental Estrogen Receptor – Negative Mammary Carcinogenesis by the Synthetic Triterpenoid CDDO-Methyl Ester and the Rexinoid LG100268

    PubMed Central

    Liby, Karen; Risingsong, Renee; Royce, Darlene B.; Williams, Charlotte R.; Yore, Mark M.; Honda, Tadashi; Gribble, Gordon W.; Lamph, William W.; Vannini, Nicola; Sogno, Ilaria; Albini, Adriana; Sporn, Michael B.

    2016-01-01

    Purpose To test whether the triterpenoid 2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oic acid methyl ester (CDDO-Me) and the rexinoid LG100268 (268) prevent the formation of estrogen receptor (ER) – negative mammary tumors or either arrest the growth or cause regression of established tumors in MMTV-neu mice. Experimental Design For prevention, mice were fed control diet, CDDO-Me (60 mg/kg diet), 268 (20 mg/kg diet), or the combination for 45 weeks. For treatment, mice with established tumors at least 4 mm in diameter were fed control diet, CDDO-Me (100 mg/kg diet), 268 (60 mg/kg diet), or the combination for 4 weeks. Results CDDO-Me and 268 significantly delayed the development of ER-negative tumors, with a 14- and 24-week delay, respectively, compared with the control group for the time required to reach 50% tumor incidence. The combination of CDDO-Me and 268 was significantly more potent than the individual drugs, as only one tumor was found in the combination group, after 45 weeks on diet, at which time all control animals had tumors. Treating established tumors with CDDO-Me arrested the growth of 86% of the tumors, and 268 induced tumor regression in 85% of tumors. CDDO-Me and 268 target different signaling pathways and cell types. CDDO-Me inhibited constitutive STAT3 phosphorylation and the degradation of IKBα in ER-negative breast cancer cells, whereas 268 blocked IKBα degradation and the release of interleukin-6 in RAW264.7 macrophage-like cells, inhibited the ability of endothelial cells to organize into networks, and blocked angiogenesis in vivo. Conclusions CDDO-Me and 268 are useful as individual drugs to prevent ER-negative mammary tumorigenesis and to treat established tumors. They synergize when used in combination for prevention. PMID:18628471

  15. Synthesis, characterization, and tyrosinase biomimetic catalytic activity of copper(II) complexes with schiff base ligands derived from α-diketones with 2-methyl-3-amino-(3 H)-quinazolin-4-one

    NASA Astrophysics Data System (ADS)

    Ramadan, Abd El-Motaleb M.; Ibrahim, Mohamed M.; Shaban, Shaban Y.

    2011-12-01

    A template condensation of α-diketones (biacetyl, benzile and 2,3-pentanedione) with 2-methyl-3-amino-(3 H)-quinazolin-4-one (AMQ) in the presence of CuX 2 (X = Cl -, Br -, NO3- or ClO4-) resulted in the formation of tetradentate Schiff base copper(II) complexes of the type [CuLX]X and [CuL]X 2. Structural characterization of the complex species was achieved by several physicochemical methods, namely elemental analysis, electronic spectra, IR, ESR, molar conductivity, thermal analysis (TAG & DTG), and magnetic moment measurements. The stereochemistry, the nature of the metal chelates, and the catalytic reactivity are markedly dependent upon the type of counter anions and the ligand substituent within the carbonyl moiety. A square planar monomeric structure is proposed for the perchlorate, nitrate, and bromide complexes, in which the counter anions are loosely bonded to copper(II) ion. For the chloride complexes, the molar conductivities and the spectral data indicated that they have square-pyramidal environments around copper(II) center. The reported copper(II) complexes exhibit promising tyrosinase catalytic activity towards the hydroxylation of phenol followed by the aerobic oxidation of the resulting catechol. A linear correlation almost exists between the catalytic reactivity and the Lewis-acidity of the central copper(II) ion created by the donating properties of the parent ligand. The steric considerations could be accounted to clarify the difference in the catalytic activity of these functional models.

  16. pH-Dependent Monomer <--> Oligomer Interconversion of Copper(II) Complexes with N-(2-R-imidazol-4-ylmethylidene)-2-aminoethylpyridine (R = Methyl, Phenyl).

    PubMed

    Matsumoto, Naohide; Motoda, Yuri; Matsuo, Toshihiro; Nakashima, Toshio; Re, Nazzareno; Dahan, Francoise; Tuchagues, Jean-Pierre

    1999-03-22

    and hexanuclear for 2'a.6H(2)O and 2'b, respectively, through single-crystal X-ray analyses and FAB-MS spectra. Variable-temperature experimental magnetic susceptibility data were well reproduced by using the Heisenberg model based on a cyclic tetranuclear structure for 1' and a cyclic hexanuclear structure for 2'a and 2'b. The reversible interconversion between the protonated monomeric and deprotonated oligomeric species were confirmed by pH-dependent potentiometric and electronic spectral titrations in aqueous solution, whereas the Pd(II) complex did not show a perfect disassembly process. PMID:11670899

  17. Experimental investigation on the mechanism of chelation-assisted, copper(II) acetate-accelerated azide-alkyne cycloaddition.

    PubMed

    Kuang, Gui-Chao; Guha, Pampa M; Brotherton, Wendy S; Simmons, J Tyler; Stankee, Lisa A; Nguyen, Brian T; Clark, Ronald J; Zhu, Lei

    2011-09-01

    A mechanistic model is formulated to account for the high reactivity of chelating azides (organic azides capable of chelation-assisted metal coordination at the alkylated azido nitrogen position) and copper(II) acetate (Cu(OAc)(2)) in copper(II)-mediated azide-alkyne cycloaddition (AAC) reactions. Fluorescence and (1)H NMR assays are developed for monitoring the reaction progress in two different solvents, methanol and acetonitrile. Solvent kinetic isotopic effect and premixing experiments give credence to the proposed different induction reactions for converting copper(II) to catalytic copper(I) species in methanol (methanol oxidation) and acetonitrile (alkyne oxidative homocoupling), respectively. The kinetic orders of individual components in a chelation-assisted, copper(II)-accelerated AAC reaction are determined in both methanol and acetonitrile. Key conclusions resulting from the kinetic studies include (1) the interaction between copper ion (either in +1 or +2 oxidation state) and a chelating azide occurs in a fast, pre-equilibrium step prior to the formation of the in-cycle copper(I)-acetylide, (2) alkyne deprotonation is involved in several kinetically significant steps, and (3) consistent with prior experimental and computational results by other groups, two copper centers are involved in the catalysis. The X-ray crystal structures of chelating azides with Cu(OAc)(2) suggest a mechanistic synergy between alkyne oxidative homocoupling and copper(II)-accelerated AAC reactions, in which both a bimetallic catalytic pathway and a base are involved. The different roles of the two copper centers (a Lewis acid to enhance the electrophilicity of the azido group and a two-electron reducing agent in oxidative metallacycle formation, respectively) in the proposed catalytic cycle suggest that a mixed valency (+2 and +1) dinuclear copper species be a highly efficient catalyst. This proposition is supported by the higher activity of the partially reduced Cu(OAc)(2) in

  18. Nickel(II) complexes of pentadentate N5 ligands as catalysts for alkane hydroxylation by using m-CPBA as oxidant: a combined experimental and computational study.

    PubMed

    Sankaralingam, Muniyandi; Balamurugan, Mani; Palaniandavar, Mallayan; Vadivelu, Prabha; Suresh, Cherumuttathu H

    2014-09-01

    A new family of nickel(II) complexes of the type [Ni(L)(CH(3)CN)](BPh(4))(2), where L=N-methyl-N,N',N'-tris(pyrid-2-ylmethyl)-ethylenediamine (L1, 1), N-benzyl-N,N',N'-tris(pyrid-2-yl-methyl)-ethylenediamine (L2, 2), N-methyl-N,N'-bis(pyrid-2-ylmethyl)-N'-(6-methyl-pyrid-2-yl-methyl)-ethylenediamine (L3, 3), N-methyl-N,N'-bis(pyrid-2-ylmethyl)-N'-(quinolin-2-ylmethyl)-ethylenediamine (L4, 4), and N-methyl-N,N'-bis(pyrid-2-ylmethyl)-N'-imidazole-2-ylmethyl)-ethylenediamine (L5, 5), has been isolated and characterized by means of elemental analysis, mass spectrometry, UV/Vis spectroscopy, and electrochemistry. The single-crystal X-ray structure of [Ni(L(3))(CH(3)CN)](BPh(4))(2) reveals that the nickel(II) center is located in a distorted octahedral coordination geometry constituted by all the five nitrogen atoms of the pentadentate ligand and an acetonitrile molecule. In a dichloromethane/acetonitrile solvent mixture, all the complexes show ligand field bands in the visible region characteristic of an octahedral coordination geometry. They exhibit a one-electron oxidation corresponding to the Ni(II) /Ni(III) redox couple the potential of which depends upon the ligand donor functionalities. The new complexes catalyze the oxidation of cyclohexane in the presence of m-CPBA as oxidant up to a turnover number of 530 with good alcohol selectivity (A/K, 7.1-10.6, A=alcohol, K=ketone). Upon replacing the pyridylmethyl arm in [Ni(L1)(CH(3)CN)](BPh(4))(2) by the strongly σ-bonding but weakly π-bonding imidazolylmethyl arm as in [Ni(L5)(CH(3)CN)](BPh(4))(2) or the sterically demanding 6-methylpyridylmethyl ([Ni(L3)(CH(3)CN)](BPh(4))(2) and the quinolylmethyl arms ([Ni(L4)(CH(3)CN)](BPh(4))(2), both the catalytic activity and the selectivity decrease. DFT studies performed on cyclohexane oxidation by complexes 1 and 5 demonstrate the two spin-state reactivity for the high-spin [(N5)Ni(II)-O(.)] intermediate (ts1(hs), ts2(doublet)), which has a low-spin state located closely in

  19. Crystal structure of high-spin tetra­aqua­bis­(2-chloro­pyrazine-κN 4)iron(II) bis­(4-methyl­benzene­sulfonate)

    PubMed Central

    Golub, Bohdan O.; Shylin, Sergii I.; Dechert, Sebastian; Malysheva, Maria L.; Gural‘skiy, Il‘ya A.

    2015-01-01

    The title salt, [FeII(C4H3ClN2)2(H2O)4](C7H7O3S)2, contains a complex cation with point group symmetry 2/m. The high-spin FeII cation is hexa­coordinated by four symmetry-related water and two N-bound 2-chloro­pyrazine mol­ecules in a trans arrangement, forming a distorted FeN2O4 octa­hedron. The three-dimensional supra­molecular structure is supported by inter­molecular O—H⋯O hydrogen bonds between the complex cations and tosyl­ate anions, and additional π–π inter­actions between benzene and pyrazine rings. The methyl H atoms of the tosyl­ate anion are equally disordered over two positions. PMID:26279865

  20. Experimental Measurements of the Secondary Electron Yield in the Experimental Measurement of the Secondary Electron Yield in the PEP-II Particle Accelerator Beam Line

    SciTech Connect

    Pivi, M.T.F.; Collet, G.; King, F.; Kirby, R.E.; Markiewicz, T.; Raubenheimer, T.O.; Seeman, J.; Le Pimpec, F.; /PSI, Villigen

    2010-08-25

    Beam instability caused by the electron cloud has been observed in positron and proton storage rings and it is expected to be a limiting factor in the performance of the positron Damping Ring (DR) of future Linear Colliders (LC) such as ILC and CLIC. To test a series of promising possible electron cloud mitigation techniques as surface coatings and grooves, in the Positron Low Energy Ring (LER) of the PEP-II accelerator, we have installed several test vacuum chambers including (i) a special chamber to monitor the variation of the secondary electron yield of technical surface materials and coatings under the effect of ion, electron and photon conditioning in situ in the beam line; (ii) chambers with grooves in a straight magnetic-free section; and (iii) coated chambers in a dedicated newly installed 4-magnet chicane to study mitigations in a magnetic field region. In this paper, we describe the ongoing R&D effort to mitigate the electron cloud effect for the LC damping ring, focusing on the first experimental area and on results of the reduction of the secondary electron yield due to in situ conditioning.

  1. Analysis of the absorptive behavior of photopolymer materials. Part II. Experimental validation

    NASA Astrophysics Data System (ADS)

    Li, Haoyu; Qi, Yue; Tolstik, Elen; Guo, Jinxin; Sheridan, John T.

    2015-01-01

    In the first part of this paper, a model describing photopolymer materials, which incorporates both the physical electromagnetic and photochemical effects taking place, was developed. This model is now validated by applying it to fit experimental data for two different types of photopolymer materials. The first photopolymer material, acrylamide/polyvinyl alcohol, is studied when four photosensitizers are used, i.e. Erythrosine B, Eosin Y, Phloxine B and Rose Bengal. The second type of photopolymer material involves phenanthrenequinone in a polymethylmethacrylate matrix. Using our model, the values of physical parameters, are extracted by numerical fitting experimentally obtained normalized transmittance growth curves. Experimental data sets for different exposure intensities, dye concentrations, and exposure geometries are studied. The advantages of our approach are demonstrated and it is shown that the parameters proposed by us to quantify the absorptive behavior in our model are both physical and can be estimated.

  2. Driving under the influence of non-alcohol drugs--An update. Part II: Experimental studies.

    PubMed

    Strand, M C; Gjerde, H; Mørland, J

    2016-07-01

    Experimental studies on the impairing effects of drugs of relevance to driving-related performance published between 1998 and 2015 were reviewed. Studies with on-the-road driving, driving simulators, and performance tests were included for benzodiazepines and related drugs, cannabis, opioids, stimulants, GHB, ketamine, antihistamines, and antidepressants. The findings in these experimental studies were briefly discussed in relation to a review of epidemiological studies published recently. The studies mainly concluded that there may be a significant psychomotor impairment after using benzodiazepines or related drugs, cannabis, opioids, GHB, or ketamine. Low doses of central stimulants did not seem to cause impairment of driving behavior. PMID:27257716

  3. A new one-dimensional Cd(II) coordination polymer with a two-dimensional layered structure incorporating 2-[(1H-imidazol-1-yl)methyl]-1H-benzimidazole and benzene-1,2-dicarboxylate ligands.

    PubMed

    Huang, Qiu Ying; Lin, Xiao Yi; Meng, Xiang Ru

    2016-06-01

    The N-heterocyclic ligand 2-[(1H-imidazol-1-yl)methyl]-1H-benzimidazole (imb) has a rich variety of coordination modes and can lead to polymers with intriguing structures and interesting properties. In the coordination polymer catena-poly[[cadmium(II)-bis[μ-benzene-1,2-dicarboxylato-κ(4)O(1),O(1'):O(2),O(2')]-cadmium(II)-bis{μ-2-[(1H-imidazol-1-yl)methyl]-1H-benzimidazole}-κ(2)N(2):N(3);κ(2)N(3):N(2)] dimethylformamide disolvate], {[Cd(C8H4O4)(C11H10N4)]·C3H7NO}n, (I), each Cd(II) ion exhibits an irregular octahedral CdO4N2 coordination geometry and is coordinated by four O atoms from two symmetry-related benzene-1,2-dicarboxylate (1,2-bdic(2-)) ligands and two N atoms from two symmetry-related imb ligands. Two Cd(II) ions are connected by two benzene-1,2-dicarboxylate ligands to generate a binuclear [Cd2(1,2-bdic)2] unit. The binuclear units are further connected into a one-dimensional chain by pairs of bridging imb ligands. These one-dimensional chains are further connected through N-H...O hydrogen bonds and π-π interactions, leading to a two-dimensional layered structure. The dimethylformamide solvent molecules are organized in dimeric pairs via weak interactions. In addition, the title polymer exhibits good fluorescence properties in the solid state at room temperature. PMID:27256695

  4. A new one-dimensional Cd(II) coordination polymer with a two-dimensional layered structure incorporating 2-[(1H-imidazol-1-yl)methyl]-1H-benzimidazole and benzene-1,2-dicarboxylate ligands.

    PubMed

    Huang, Qiu Ying; Lin, Xiao Yi; Meng, Xiang Ru

    2016-06-01

    The N-heterocyclic ligand 2-[(1H-imidazol-1-yl)methyl]-1H-benzimidazole (imb) has a rich variety of coordination modes and can lead to polymers with intriguing structures and interesting properties. In the coordination polymer catena-poly[[cadmium(II)-bis[μ-benzene-1,2-dicarboxylato-κ(4)O(1),O(1'):O(2),O(2')]-cadmium(II)-bis{μ-2-[(1H-imidazol-1-yl)methyl]-1H-benzimidazole}-κ(2)N(2):N(3);κ(2)N(3):N(2)] dimethylformamide disolvate], {[Cd(C8H4O4)(C11H10N4)]·C3H7NO}n, (I), each Cd(II) ion exhibits an irregular octahedral CdO4N2 coordination geometry and is coordinated by four O atoms from two symmetry-related benzene-1,2-dicarboxylate (1,2-bdic(2-)) ligands and two N atoms from two symmetry-related imb ligands. Two Cd(II) ions are connected by two benzene-1,2-dicarboxylate ligands to generate a binuclear [Cd2(1,2-bdic)2] unit. The binuclear units are further connected into a one-dimensional chain by pairs of bridging imb ligands. These one-dimensional chains are further connected through N-H...O hydrogen bonds and π-π interactions, leading to a two-dimensional layered structure. The dimethylformamide solvent molecules are organized in dimeric pairs via weak interactions. In addition, the title polymer exhibits good fluorescence properties in the solid state at room temperature.

  5. Experimental determination of equilibrium constant for the complexing reaction of nitric oxide with hexamminecobalt(II) in aqueous solution.

    PubMed

    Mao, Yan-Peng; Chen, Hua; Long, Xiang-Li; Xiao, Wen-de; Li, Wei; Yuan, Wei-Kang

    2009-02-15

    Ammonia solution can be used to scrub NO from the flue gases by adding soluble cobalt(II) salts into the aqueous ammonia solutions. The hexamminecobalt(II), Co(NH3)6(2+), formed by ammonia binding with Co2+ is the active constituent of eliminating NO from the flue gas streams. The hexamminecobalt(II) can combine with NO to form a complex. For the development of this process, the data of the equilibrium constants for the coordination between NO and Co(NH3)6(2+)over a range of temperature is very important. Therefore, a series of experiments were performed in a bubble column to investigate the chemical equilibrium. The equilibrium constant was determined in the temperature range of 30.0-80.0 degrees C under atmospheric pressure at pH 9.14. All experimental data fit the following equation well: [see text] where the enthalpy and entropy are DeltaH degrees = - (44.559 +/- 2.329)kJ mol(-1) and DeltaS degrees = - (109.50 +/- 7.126) J K(-1)mol(-1), respectively.

  6. Short Hairpin RNA Causes the Methylation of Transforming Growth Factor-β Receptor II Promoter and Silencing of the Target Gene in Rat Hepatic Stellate Cells

    PubMed Central

    Kim, Jin-Wook; Zhang, Yan-Hong; Zern, Mark A; Rossi, John J.; Wu, Jian

    2008-01-01

    Small interfering RNA (siRNA) induces transcriptional gene silencing (TGS) in plant and animal cells. RNA dependent DNA methylation (RdDM) accounts for TGS in plants, but it is unclear whether siRNA induces RdDM in mammalian cells. To determine whether stable expression of short hairpin siRNA (shRNA) induces DNA methylation in mammalian cells, we transduced rat hepatic stellate SBC10 cells with lentiviral vectors which encode an U6 promoter-driven shRNA expression cassette homologous to the transforming growth factor-β receptor (TGFβRII) promoter region. Sequencing analysis of bisulfite-modified genomic DNA showed the methylation of cytosine residues both in CpG dinucleotides and non-CpG sites around the target region of the TGFβRII promoter in SBC10 cells transduced with the promoter-targeting lentiviral vector. In these cells, real-time RT-PCR showed a decrease in TGFβRII mRNA levels which were reversed by treatment with 5-aza-2-deoxycytidine. Our results demonstrate that recombinant lentivirus-mediated shRNA delivery resulted in the methylation of the homologous promoter area in mammalian cells, and this approach may be used as a tool for transcriptional gene silencing by epigenetic modification of mammalian cell promoters. PMID:17533113

  7. The HIT-II Spherical Torus: Physics and Key Experimental Results

    NASA Astrophysics Data System (ADS)

    Redd, A. J.; Hamp, W. T.; Izzo, V. A.; Jarboe, T. R.; Nelson, B. A.; O'Neill, R. G.; Raman, R.; Sieck, P. E.; Smith, R. J.

    2004-11-01

    Discharges in the HIT-II spherical torus device [Redd et al., Phys. Plasmas 9, 2006 (2002)] can be driven by either Ohmic or Coaxial Helicity Injection (CHI) current drive. A new CHI operating regime has been explored, with toroidal plasma currents of up to 350 kA, I_p/I_TF ratios of up to 1.2, and internal probing data which may demonstrate the formation of a closed-flux core. The key to acheiving these results is the magnetic field shear in the CHI injector region, with a minimum shear necessary for current build-up. Ohmic plasma performance has also improved, with peak currents up to 300 kA, with and without transient CHI startup. The CHI startup technique [Raman et al., Phys. Plasmas 11, 2565 (2004)] provides more robust discharges, with a wider operating space and more efficient use of the transformer Volt-seconds, than unassisted Ohmic. Finally, CHI can be used to enhance an Ohmic plasma current without significantly degrading the quality of the discharge. Results will be presented for each HIT--II operating regime, including empirical performance scalings and applicable parametric operating spaces.

  8. Controlling and culturing diversity: experimental zoology before World War II and Vienna's Biologische Versuchsanstalt.

    PubMed

    Logan, Cheryl A; Brauckmann, Sabine

    2015-04-01

    Founded in Vienna in 1903, the Institute for Experimental Biology pioneered the application of experimental methods to living organisms maintained for sustained periods in captivity. Its Director, the zoologist Hans Przibram, oversaw until 1938, the attempt to integrate ontogeny with studies of inheritance using precise and controlled measurements of the impact of environmental influences on the emergence of form and function. In the early years, these efforts paralleled and even fostered the emergence of experimental biology in America. But fate intervened. Though the Institute served an international community, most of its resident scientists and staff were of Jewish ancestry. Well before the Nazis entered Austria in 1938, these men and women were being fired and driven out; some, including Przibram, were eventually killed. We describe the unprecedented facilities built and the topics addressed by the several departments that made up this Institute, stressing those most relevant to the establishment and success of the Journal of Experimental Zoology, which was founded just a year later. The Institute's diaspora left an important legacy in North America, perhaps best embodied by the career of the developmental neuroscientist Paul Weiss.

  9. Superdiffusive heat conduction in semiconductor alloys. II. Truncated Lévy formalism for experimental analysis

    NASA Astrophysics Data System (ADS)

    Vermeersch, Bjorn; Mohammed, Amr M. S.; Pernot, Gilles; Koh, Yee Rui; Shakouri, Ali

    2015-02-01

    Nearly all experimental observations of quasiballistic heat flow are interpreted using Fourier theory with modified thermal conductivity. Detailed Boltzmann transport equation (BTE) analysis, however, reveals that the quasi-ballistic motion of thermal energy in semiconductor alloys is no longer Brownian but instead exhibits Lévy dynamics with fractal dimension α <2 . Here, we present a framework that enables full three-dimensional experimental analysis by retaining all essential physics of the quasiballistic BTE dynamics phenomenologically. A stochastic process with just two fitting parameters describes the transition from pure Lévy superdiffusion as short length and time scales to regular Fourier diffusion. The model provides accurate fits to time domain thermoreflectance raw experimental data over the full modulation frequency range without requiring any "effective" thermal parameters and without any a priori knowledge of microscopic phonon scattering mechanisms. Identified α values for InGaAs and SiGe match ab initio BTE predictions within a few percent. Our results provide experimental evidence of fractal Lévy heat conduction in semiconductor alloys. The formalism additionally indicates that the transient temperature inside the material differs significantly from Fourier theory and can lead to improved thermal characterization of nanoscale devices and material interfaces.

  10. The Experimental Manpower Laboratory for Corrections: Phase II. Final Report (March 1, 1970-August 31, 1971).

    ERIC Educational Resources Information Center

    Rehabilitation Research Foundation, Elmore, AL.

    This report covers these five major projects of the Experimental Manpower Laboratory for Corrections: (1) a manpower training program for Alabama prisoners, (2) an experiment in contingency management, (3) implementation of token economy in Draper Correctional Center, (4) a manpower training project for correctional officers, and (5) a followup…

  11. General Science, Ninth Grade: Theme I and Theme II. Student Laboratory Manual. Experimental.

    ERIC Educational Resources Information Center

    New York City Board of Education, Brooklyn, NY. Div. of Curriculum and Instruction.

    This ninth grade student manual was developed to be used in conjunction with some of the experimental science activities described in the teacher's guide. It contains laboratory worksheets for: (1) measurement; (2) basic energy concepts; (3) heat energy; (4) light; (5) sound; (6) electricity; and (7) present and future energy resources. Additional…

  12. Experimental and computational investigation of the sII binary He-THF hydrate.

    PubMed

    Papadimitriou, Nikolaos I; Tsimpanogiannis, Ioannis N; Stubos, Athanassios K; Martín, Angel; Rovetto, Laura J; Florusse, Louw J; Peters, Cor J

    2011-02-17

    The objective of this work is to study the binary He-THF hydrate with both experimental and theoretical approaches. Experimental data for the hydrate equilibrium at pressures up to 12.6 MPa are reported for the binary He-THF hydrate with stoichiometric THF composition (i.e., 5.56 mol % THF). These data are used to calibrate a thermodynamic model [J. Phys. Chem. C2009, 113, 422] for the prediction of hydrate equilibrium that is based on the van der Waals-Platteeuw statistical thermodynamic theory. Then this model is used to extrapolate the obtained experimental data to much higher pressures, and good agreement is observed with other available experimental data at pressures up to 150 MPa. This model is also capable of estimating the cavity occupancies for He and THF. The results show that the large cavities are completely occupied by THF molecules, whereas the small ones are partially occupied by He atoms. The He occupancy of the small cavities is less than 60%, even at high pressures (100 MPa). The occupancies predicted from this model are in close agreement with similar results from molecular simulations and a previously reported thermodynamic approach.

  13. Density functional theory study of oxygen-atom insertion into metal-methyl bonds of iron(II), ruthenium(II), and osmium(II) complexes: study of metal-mediated C-O bond formation.

    PubMed

    Pardue, Daniel B; Mei, Jiajun; Cundari, Thomas R; Gunnoe, T Brent

    2014-03-17

    Metal-mediated C-O bond formation is a key step in hydrocarbon oxygenation catalytic cycles; however, few examples of this reaction have been reported for low-oxidation-state complexes. Oxygen insertion into a metal-carbon bond of Cp*M(CO)(OPy)R (Cp* = η(5)-pentamethylcyclopentadienyl; R = Me, Ph; OPy = pyridine-N-oxide; M = Fe, Ru, Os) was analyzed via density functional theory calculations. Oxygen-atom insertions through a concerted single-step organometallic Baeyer-Villiger pathway and a two-step pathway via a metal-oxo intermediate were studied; calculations predict that the former pathway was lower in energy. The results indicated that functionalization of M-R to M-OR (R = Me, Ph) is plausible using iron(II) complexes. Starting from Cp*Fe(CO)(OPy)Ph, the intermediate Fe-oxo showed oxyl character and, thus, is best considered an Fe(III)O(•-) complex. Oxidation of the π-acid ancillary ligand CO was facile. Substitutions of CO with dimethylamide and NH3 were calculated to lower the activation barrier by ∼1-2 kcal/mol for formation of the Fe(III)O(•-) intermediate, whereas a chloride ligand raised the activation barrier to 26 kcal/mol from 22.9 kcal/mol. PMID:24571202

  14. Mercury methylation, export and bioaccumulation in rice agriculture - model results from comparative and experimental studies in 3 regions of the California Delta, USA

    NASA Astrophysics Data System (ADS)

    Windham-Myers, L.; Fleck, J.; Eagles-Smith, C.; Ackerman, J.

    2013-12-01

    Seasonally flooded wetland ecosystems are often poised for mercury (Hg) methylation, thus becoming sources of methylmercury (MeHg) to in situ and downstream biota. The seasonal flooding associated with cultivation of rice (Oryza sativa) also generates MeHg, which may be stored in sediment or plants, bioaccumulated into fauna, degraded or exported, depending on hydrologic and seasonal conditions. While many U.S. waters are regulated for total Hg concentrations based on fish targets, California's Sacramento-San Joaquin Delta (Delta) will soon implement the first MeHg total maximum daily load (TMDL) control program. Since 2007, a conceptual model (DRERIP-MCM) and several ecosystem-level studies have been advanced to better understand the mechanisms behind Hg methylation, export and bioaccumulation within Delta wetlands, including rice agriculture. Three Delta rice-growing regions (Yolo Bypass, Cosumnes River, Central Delta) of varied soil characteristics, mining influences and hydrology, were monitored over full crop years to evaluate annual MeHg dynamics. In addition to fish tissue Hg accumulation, a broad suite of biogeochemical and hydrologic indices were assessed and compared between wetland types, seasons, and regions. In general, Delta rice fields were found to export MeHg during the post-harvest winter season, and promote MeHg uptake in fish and rice grain during the summer growing season. As described in a companion presentation (Eagles-Smith et al., this session), the experimental Cosumnes River study suggests that rice-derived dissolved organic carbon (DOC) fuels MeHg production and uptake into aquatic foodwebs. Explicit DRERIP-MCM linkages for the role of rice-DOC in MeHg production, export and bioaccumulation were verified across two summers (2011, 2012): rice biomass and root productivity influenced porewater DOC availability and microbial processes, which drove sediment MeHg production and flux to surface water, promoting MeHg bioaccumulation in fish

  15. Crystal structure of di­chlorido­{2-methyl-2-[(pyridin-2-ylmeth­yl)amino]­propan-1-ol-κ3 N,N′,O}copper(II) from synchrotron data

    PubMed Central

    Shin, Jong Won; Lee, Dong Won; Kim, Dae-Woong; Moon, Dohyun

    2016-01-01

    The title compound, [CuCl2(C10H16N2O)], has been synthesized and characterized by synchrotron single-crystal X-ray diffraction and FT–IR spectroscopy. The 2-methyl-2-[(pyridin-2-ylmeth­yl)amino]­propan-1-ol (mpmapOH) ligand, including pyridine, amine and hy­droxy groups, was synthesized by the reaction of 2-amino-2-methyl­propan-1-ol with pyridine-2-carbaldehyde and was characterized by NMR spectroscopy. In its CuII complex, the metal ion has a distorted square-pyramidal coordination geometry with two N and one O atom of the mpmapOH ligand and one chloride anion in the equatorial plane, and the second chloride in an axial position. The bond lengths involving the CuII ion range from 1.9881 (10) to 2.0409 (9) for the Cu—N and Cu—O bonds, and from 2.2448 (5) to 2.5014 (6) Å for the equatorial and axial Cu—Cl bonds, respectively. Inter­molecular hydrogen bonds (N—H⋯Cl and O—H⋯Cl) and face-to-face π–π inter­actions stabilize the mol­ecular structure and give rise to a two-dimensional supra­molecular structure extending parallel to (101). PMID:27746928

  16. DNA Methylation

    PubMed Central

    Marinus, M.G.; Løbner-Olesen, A.

    2014-01-01

    The DNA of E. coli contains 19,120 6-methyladenines and 12,045 5-methylcytosines in addition to the four regular bases and these are formed by the postreplicative action of three DNA methyltransferases. The majority of the methylated bases are formed by the Dam and Dcm methyltransferases encoded by the dam (DNA adenine methyltransferase) and dcm (DNA cytosine methyltransferase) genes. Although not essential, Dam methylation is important for strand discrimination during repair of replication errors, controlling the frequency of initiation of chromosome replication at oriC, and regulation of transcription initiation at promoters containing GATC sequences. In contrast, there is no known function for Dcm methylation although Dcm recognition sites constitute sequence motifs for Very Short Patch repair of T/G base mismatches. In certain bacteria (e.g., Vibrio cholerae, Caulobacter crescentus) adenine methylation is essential and in C. crescentus, it is important for temporal gene expression which, in turn, is required for coordinating chromosome initiation, replication and division. In practical terms, Dam and Dcm methylation can inhibit restriction enzyme cleavage; decrease transformation frequency in certain bacteria; decrease the stability of short direct repeats; are necessary for site-directed mutagenesis; and to probe eukaryotic structure and function. PMID:26442938

  17. Disparate MHC class II haplotypes in myelin oligodendrocyte glycoprotein- and myelin basic protein-induced experimental autoimmune encephalomyelitis.

    PubMed

    Muhallab, Saad; Dahlman, Ingrid; Wallström, Erik

    2005-04-01

    The major histocompatibility complex (MHC) regulates multiple sclerosis (MS) and its model experimental autoimmune encephalomyelitis (EAE). We created four new intra-MHC recombinant rat strains, between the MHC haplotypes RT1(n) (BN) and RT1(l) (LEW) on the LEW background, to define disease regulation and localization within the MHC. Immunization with recombinant myelin oligodendrocyte glycoprotein (a.a.1-125; MOG)/IFA induced EAE in strains expressing the MHC class II allele RT1.B(n), whereas strains expressing the RT1.B(l) were resistant. In myelin basic protein peptide (MBP(GP)63-88)/CFA-induced EAE, RT1.B(l) expressing strains were susceptible whereas strains expressing the RT1.B(n) were resistant. High levels of antigen-specific IFN-gamma secreting lymphoid cells and antigen-specific serum IgG antibodies were only recorded in rats with an MHC class II allele that permitted MOG- or MBP-EAE, respectively. Genetically, we localized the MHC regulation of the investigated EAE models to the central part of the MHC, containing the MHC class II (RT1.B/D) and the centromeric parts of the MHC class III. No influences were evident from the classical MHC class I (RT1.A), the telomeric parts of the MHC class III or the non-classical MHC class I (RT1.C/E/M) in contrast to previous reports. The MHC class II haplotype-specific regulation of EAE induced with two different CNS antigens demonstrates a strikingly specific MHC-association even within the same target organ. PMID:15748954

  18. Experimental study of weak intersystem lines and related strong persistent lines of Ne II

    SciTech Connect

    Bridges, J. M.; Wiese, W. L.

    2007-08-15

    We operated a high-current hollow cathode discharge in pure neon at pressures from 93 to 173 Pa and measured the branching fractions of Ne II emission lines originating from several 2p{sup 5} 3p, 3d, and 4f levels, for which lifetime data were available in the literature. This allowed the determination of transition probabilities for all downward transitions, which included a number of weak intersystem lines. We focused our study on these weak lines, using care to assure correct identifications and accurate intensity measurements, in spite of the presence of much stronger other lines in their vicinity. In contrast to an earlier experiment, we achieved close agreement with a recent multiconfiguration Hartree-Fock calculation.

  19. A second monoclinic polymorph of {bis­[5-methyl-3-(trifluoro­meth­yl)pyrazol-1-yl]borato}{tris­[5-methyl-3-(trifluoro­meth­yl)pyrazol-1-yl]borato}cobalt(II): a structure containing a B—H⋯Co agostic inter­action

    PubMed Central

    Stibrany, Robert T.; Potenza, Joseph A.

    2011-01-01

    The title compound, [Co(C10H10BF6N4)(C15H13BF9N6)], is a polymorph of the previously reported neutral cobalt(II) complex [Stibrany & Potenza (2010 ▶). Acta Cryst. E66, m506–m507], which contains one each of the monoanionic ligands, bis­[5-methyl-3-(trifluoro­meth­yl)pyrazol-1-yl]borate (Bp) and tris­[5-methyl-3-(trifluoro­meth­yl)pyrazol-1-yl]borate (Tp). A distorted octahedral coordination geometry of the CoII atom results from ligation of an H atom, which is part of an agostic B—H⋯Co inter­action [H⋯Co = 2.12 (3) Å], and by five imine N atoms, two from a Bp ligand and three from a Tp ligand. Weak intra- and inter­molecular C—F⋯π inter­actions with F⋯centroid distances ranging from 3.025 (4) to 3.605 (4) Å are observed. PMID:21836897

  20. Computational and experimental prediction of dust production in pebble bed reactors, Part II

    SciTech Connect

    Mie Hiruta; Gannon Johnson; Maziar Rostamian; Gabriel P. Potirniche; Abderrafi M. Ougouag; Massimo Bertino; Louis Franzel; Akira Tokuhiro

    2013-10-01

    This paper is the continuation of Part I, which describes the high temperature and high pressure helium environment wear tests of graphite–graphite in frictional contact. In the present work, it has been attempted to simulate a Pebble Bed Reactor core environment as compared to Part I. The experimental apparatus, which is a custom-designed tribometer, is capable of performing wear tests at PBR relevant higher temperatures and pressures under a helium environment. This environment facilitates prediction of wear mass loss of graphite as dust particulates from the pebble bed. The experimental results of high temperature helium environment are used to anticipate the amount of wear mass produced in a pebble bed nuclear reactor.

  1. Studies on experimental Jembrana disease in Bali cattle. II. Clinical signs and haematological changes.

    PubMed

    Soesanto, M; Soeharsono, S; Budiantono, A; Sulistyana, K; Tenaya, M; Wilcox, G E

    1990-07-01

    The clinical and haematological changes which occurred in 18 Bali cattle (Bos javanicus) experimentally infected with Jembrana disease are described. The major clinical signs were an elevated rectal body temperature persisting for 7 days (range 5 to 12 days), lethargy, anorexia, enlargement of the superficial lymph nodes, a mild ocular and nasal discharge, diarrhoea with blood in the faeces and pallor of the mucous membranes. Not all of these changes occurred in all affected cattle. The major haematological changes included leucopenia, lymphopenia, eosinopenia and a slight neutropenia, a mild thrombocytopenia, a normocytic normochromic anaemia, elevated blood urea concentrations and reduced total plasma protein. The mortality rate in the experimentally infected cattle was 17 per cent. The similarity of Jembrana disease to malignant catarrhal fever and to diseases of cattle associated with Ehrlichia is discussed.

  2. The effect of selective photosuppression of sensitized pathogenic microflora: Part II. Experimental validation on animals

    NASA Astrophysics Data System (ADS)

    Masychev, Viktor I.; Risovannaya, Olga N.

    2005-03-01

    Results of in vivo experiments have shown the maximum effectiveness of combined use of photo sensitizer 0,1% gel Radachlorine simultaneously with continuous and super pulse low energy irradiation of the diode laser with energy density 400 J/cm2, and power 1W. Given parameters have lead to complete elimination of Streptococcus pyogenes from inflammation foci in oral cavity of experimental animals.

  3. Test program element II blanket and shield thermal-hydraulic and thermomechanical testing, experimental facility survey

    SciTech Connect

    Ware, A.G.; Longhurst, G.R.

    1981-12-01

    This report presents results of a survey conducted by EG and G Idaho to determine facilities available to conduct thermal-hydraulic and thermomechanical testing for the Department of Energy Office of Fusion Energy First Wall/Blanket/Shield Engineering Test Program. In response to EG and G queries, twelve organizations (in addition to EG and G and General Atomic) expressed interest in providing experimental facilities. A variety of methods of supplying heat is available.

  4. Ion exchange chromatography of proteins-predictions of elution curves and operating conditions. II. Experimental verification.

    PubMed

    Yamamoto, S; Nakanishi, K; Matsuno, R; Kamijubo, T

    1983-05-01

    The applicability and validity of the model developed in Part I were confirmed experimentally. In this article, various proteins were eluted both by stepwise and linear gradient elution on DEAE ion exchangers under a variety of experimental conditions. Adsorption isotherms were measured as a function of ionic strength in batch experiments. The moment method was employed for the determination of various parameters such as the gel-phase diffusion coefficient and the longitudinal dispersion coefficient. By use of these parameters and the experimentally measured ionic strength of the peak position, the number of plates was determined according to the method described in Part I. Theoretical elution curves were calculated with the experimentally measured adsorption equilibria and the number of plates. Good agreement was observed between theory an experiments. Various factors affecting the separation were investigated. It was found that the effect of the number of plates for salts, N'(p), was negligible except the case of stepwise elution of high ionic strength buffer. When elution curves were symmetrical, the widths of the elution curves were inversely proportional to the square root of the number of plates of proteins, N(p), as in other chromatographic techniques. A simple graphical method for prediction of the peak position in linear gradient elution described in Part I was found applicable when the elution curves were symmetrical. A useful correlation of prediction of the peak width in a linear gradient elution was proposed on the basis of the approximate solution derived in Part I of this study. This graphical method and correlation permit easy prediction of the peak position and peak width in linear gradient elution in the case of symmetrical elution curves.

  5. Modeling the influence of cyclodextrins on oral absorption of low solubility drugs: II. Experimental validation.

    PubMed

    Gamsiz, Ece Dilber; Miller, Lee; Thombre, Avinash G; Ahmed, Imran; Carrier, Rebecca Lyn

    2010-02-01

    A model was developed for predicting the influence of cyclodextrins (CDs) delivered as a physical mixture with drug on oral absorption. CDs are cyclic oligosaccharides which form inclusion complexes with many drugs and are often used as solubilizing agents. The purpose of this work is to compare the simulation predictions with in vitro as well as in vivo experimental results to test the model's ability to capture the influence of CD on key processes in the gastrointestinal (GI) tract environment. Dissolution and absorption kinetics of low solubility drugs (Naproxen and Nifedipine) were tested in the presence and absence of CD in a simulated gastrointestinal environment. Model predictions were also compared with in vivo experimental results (Glibenclamide and Carbamazepine) from the literature to demonstrate the model's ability to predict oral bioavailability. Comparisons of simulation and experimental results indicate that a model incorporating the influence of CD (delivered as a physical mixture) on dissolution kinetics and binding of neutral drug can predict trends in the influence of CD on bioavailability. Overall, a minimal effect of CD dosed as a physical mixture was observed and predicted. Modeling may aid in enabling rational design of CD containing formulations.

  6. Electronic structure of CuTPP and CuTPP(F) complexes: a combined experimental and theoretical study II.

    PubMed

    Mangione, Giulia; Sambi, Mauro; Carlotto, Silvia; Vittadini, Andrea; Ligorio, Giovanni; Timpel, Melanie; Pasquali, Luca; Giglia, Angelo; Nardi, Marco Vittorio; Casarin, Maurizio

    2016-09-28

    The unoccupied electronic structure of thick films of tetraphenylporphyrin and tetrakis(pentafluorophenyl)porphyrin Cu(ii) complexes (hereafter, CuTPP and CuTPP(F)) deposited on Au(111) has been studied by combining the outcomes of near-edge X-ray absorption fine structure (NEXAFS) spectroscopy with those of spin-unrestricted time-dependent density functional (TD-DFT) calculations carried out either within the scalar relativistic zeroth order regular approximation (ZORA) framework (C, N and F K-edges) or by using the Tamm-Dancoff approximation coupled to ZORA and including spin-orbit effects (Cu L2,3-edges). Similarly to the modelling of NEXAFS outcomes pertaining to other Cu(ii) complexes, the agreement between theory and experiment is more than satisfactory, thus confirming the open-shell TD-DFT to be a useful tool to look into NEXAFS results pertinent to Cu(ii) compounds. The combined effect of metalation and phenyl (Ph) fluorine decoration is found to favour an extensive mixing between (Ph)σ* and pristine porphyrin macrocyle (pmc) (pmc)π* virtual levels. The lowest lying excitation in the C and N K-edge spectra of both CuTPP and CuTPP(F) is associated with a ligand-to-metal-charge-transfer transition, unambiguously revealed in the (CuTPP)N K-edge spectral pattern. Moreover, the comparison with literature data pertaining to the modelling of the (Cu(II))L2,3 features in the phthalocyanine-Cu(ii) (CuPc) complex provided further insights into how metal-to-ligand-charge-transfer transitions associated with excitations from 2p(Cu(II)) AOs to low-lying, ligand-based π* MOs may contribute to the Cu(ii) L2,3-edge intensity and thus weaken its believed relationship with the Cu(ii)-ligand symmetry-restricted covalency. Despite the coordinative pocket of CuTPP/CuTPP(F) mirroring CuPc, the ligand-field strength exerted by the phthalocyanine ligand on the Cu(ii) centre is experimentally found and theoretically confirmed to be slightly stronger than that experienced by Cu

  7. Adaptation and cognition. II. Experimental study of the homospatial process in artistic creativity.

    PubMed

    Rothenberg, A; Sobel, R S

    1981-07-01

    In a previously reported experimental study from an ongoing program of research on the creative process, the type of cognition designated as homospatial thinking was shown to function in the creation of literary metaphor. Homospatial thinking consists of actively conceiving two or more discrete entities occupying the same space, a conception leading to the articulation of new identities. Under experimental conditions involving facilitation of homospatial thinking through presentation of superimposed visual images, and control presentation of the same images separated and side by side, the superimposed presentation stimulated significantly more creative literary metaphors. In the currently reported experiment, the effect of such stimuli on creation in the visual arts was assessed. Forty-three artist subjects were randomly assigned either to a control group viewing three sets of slide photographs paired side by side on a projection screen or to an experimental group viewing the identical pairs of slide images superimposed on each other. Each subject created a pastel drawing stimulated by each of the three slide pairs. Resulting drawings were categorized according to the type of composition produced and quality of all drawings were independently rated by two internationally prominent artists. The primary results were that drawings produced in the superimposed slide condition which contained elements from both slides intermingled together were rated significantly more creative than a single element composition and also more creative than similar composition drawings stimulated by the separated slide condition (p less than .05). Production of a final drawing in which individual components are recognizable and intermingled together in response to the superimposed stimulus condition indicates the operation of homospatial thinking involving elements occupying the same space. Consequently, the results indicate a relationship between homospatial thinking and creative visual

  8. A mathematical model of ethanol fermentation from cheese whey. II. Simulation and comparison with experimental data

    SciTech Connect

    Wang, Chen-Jen; Bajpai, R.K.

    1997-12-31

    A cybernetic model for microbial growth on mixed substrates was used to simulate the anaerobic fermentation of cheese whey and multiple sugars in semisynthetic media by Kluyveromyces marxianus CBS 397. The model simulations quite successfully predicted the observed behavior in batch and during transients in continuous operation, in single-substrate systems as well as in media involving multiple substrates, and in semisynthetic and reconstituted cheese whey solutions. The results of simulations and their comparison with the experimental data are presented. 7 refs., 11 figs., 2 tabs.

  9. Experimental investigation and numerical modeling of carbonation process in reinforced concrete structures Part II. Practical applications

    SciTech Connect

    Saetta, Anna V.; Vitaliani, Renato V

    2005-05-01

    The mathematical-numerical method developed by the authors to predict the corrosion initiation time of reinforced concrete structures due to carbonation process, recalled in Part I of this work, is here applied to some real cases. The final aim is to develop and test a practical method for determining the durability characteristics of existing buildings liable to carbonation, as well as estimating the corrosion initiation time of a building at the design stage. Two industrial sheds with different ages and located in different areas have been analyzed performing both experimental tests and numerical analyses. Finally, a case of carbonation-induced failure in a prestressed r.c. beam is presented.

  10. Effects of acidification on mercury methylation, demethylation, and volatilization in sediments from an acid-susceptible lake.

    PubMed Central

    Steffan, R J; Korthals, E T; Winfrey, M R

    1988-01-01

    The effect of experimental acidification on mercury methylation, demethylation, and volatilization was examined in surficial sediment samples from a weakly buffered northern Wisconsin lake. All mercury transformations were measured with radioisotopic tracers. Acidification of sediment pH with H2SO4, HCl, or HNO3 significantly decreased 203Hg(II) methylation. Acidification of pH 6.1 (ambient) sediments to pH 4.5 with either H2SO4 or HCl inhibited methylation by over 65%. The decreased methylation was due to the increased hydrogen ion concentration because methylation was not affected by concentrations of Na2SO4 or NaCl equimolar to the amount of acid added. Inhibition of methylation was observed even after prolonged acidification of sediments to pH 5.0 for up to 74 days. Acidification of sediments to pH 5.5, 4.5, and 3.5 with HNO3 resulted in a near complete inhibition of methylation at each pH. Similarly, the addition of equimolar amounts of NaNO3 resulted in a near complete inhibition of methylation, indicating that the inhibition was due to the nitrate ion rather than to the acidity. Demethylation of methyl mercury was not affected by pHs between 8.0 and 4.4, but sharply decreased below pH 4.4. Volatilization of 203Hg(II) from surface sediments was less than 2% of methylation activity and was not significantly different from that in killed sediments. This study indicated that acidification of sediments inhibits mercury methylation and that the observed increase in the mercury burdens in fish from low pH lakes is not due to increased production of methylmercury in sediments. PMID:3178208

  11. Subcooled flow film boiling across a horizontal cylinder. Part II. Comparison to experimental data

    SciTech Connect

    Chou, X.S.; Sankaran, S.; Witte, L.C. )

    1995-02-01

    In this paper, the results of a rigorous heat transfer analysis of subcooled flow film boiling over a heated cylinder are compared to experimental data. The analysis includes both the influence of the front part of the heater and the wake region behind the heater. Experiments using Freon-113 were conducted at subcooling levels up to 58[degree]C and at velocities up to 3.81 m/s. The configuration was upflowing Freon-113 in crossflow over a 0.635-cm electric heater. A comparison of these data as well as other available experimental data to the analysis of Chou and Witte showed good agreement as long as the subcooling level of the liquid was substantial - that is, for liquid Jakob numbers above about 0.04. This represents a considerable improvement over other models that have been developed to predict subcooled flow boiling heat transfer. A method using a temperature correction to a constant-property heat transfer solution that corresponds to the full variable-property solution is also presented, and applied to water and Freon-113. 11 refs., 5 figs., 2 tabs.

  12. Performance of Higher Order Campbell methods, Part II: calibration and experimental application

    NASA Astrophysics Data System (ADS)

    Elter, Zs.; de Izarra, G.; Filliatre, P.; Jammes, C.; Pázsit, I.

    2016-11-01

    Applying Higher Order Campbelling methods in neutron flux monitoring with fission chambers is advantageous due to their capabilities to suppress the impact of unwanted noises and signal contributions (such as gamma radiation). This work aims to verify through experimental results that the basic assumptions behind the Higher Order Campelling methods are valid in critical reactors. The experiments, reported in this work, were performed at the MINERVE reactor in Cadarache. It is shown that the calibration of a fission chamber and the associated electronic system is possible in higher order mode. With the use of unbiased cumulant estimators and with digital processing, it is shown that over a wide count rate range, accurate count rate estimation can be achieved based on signal samples of a few ms, which is a significant progress compared to similar experimental results in the literature. The difference between the count rate estimated by pulse counting and by the Higher Order Campelling is less than 4%. The work also investigates the possibility of monitoring transient events. For this purpose, a control rod drop event was followed in Higher Order Campbelling mode.

  13. Experimental and computational approaches of a novel methyl (2E)-2-{[N-(2-formylphenyl)(4-methylbenzene)sulfonamido]methyl}-3-(4-chlorophenyl)prop-2-enoate: A potential antimicrobial agent and an inhibition of penicillin-binding protein

    NASA Astrophysics Data System (ADS)

    Murugavel, S.; Vetri velan, V.; Kannan, Damodharan; Bakthadoss, Manickam

    2016-07-01

    The title compound methyl(2E)-2-{[N-(2-formylphenyl) (4-methylbenzene)sulfonamido]methyl}-3-(4-chlorophenyl) prop-2-enoate (MFMSC) has been synthesized and single crystals were grown by slow evaporation solution growth technique at room temperature. Structural and vibrational spectroscopic studies were carried out by using single crystal X-ray diffraction, FT-IR and NMR spectral analysis together with DFT method using GAUSSIAN'03 software. The detailed interpretation of the vibrational spectra has been carried out by VEDA program. NBO analysis, Mulliken charge analysis, HOMO-LUMO, MEP, Global chemical reactivity descriptors and thermodynamic properties have been analyzed. The hyperpolarisability calculation reveals the present material has a reasonably good propensity for nonlinear optical activity. The obtained antimicrobial activity results indicate that the compound shows good to moderate activity against all tested bacterial and fungal pathogens. A computational study was also carried out to predict the drug-likeness and ADMET properties of the title compound. Due to the different potential biological activity of the title compound, molecular docking study is also reported and the compound might exhibit inhibitory activity against penicillin-binding protein PBP-2X.

  14. Methyl chloride

    Integrated Risk Information System (IRIS)

    Methyl chloride ; CASRN 74 - 87 - 3 ( 07 / 17 / 2001 ) Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for

  15. Methyl acrylate

    Integrated Risk Information System (IRIS)

    Methyl acrylate ; CASRN 96 - 33 - 3 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Ef

  16. Methyl chlorocarbonate

    Integrated Risk Information System (IRIS)

    Methyl chlorocarbonate ; CASRN 79 - 22 - 1 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinog

  17. Methyl isocyanate

    Integrated Risk Information System (IRIS)

    Methyl isocyanate ; CASRN 624 - 83 - 9 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic

  18. Methyl parathion

    Integrated Risk Information System (IRIS)

    Methyl parathion ; CASRN 298 - 00 - 0 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic

  19. Methyl methacrylate

    Integrated Risk Information System (IRIS)

    Methyl methacrylate ; CASRN 80 - 62 - 6 ( 03 / 02 / 98 ) Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments f

  20. Methyl iodide

    Integrated Risk Information System (IRIS)

    Methyl iodide ; CASRN 74 - 88 - 4 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effe

  1. Microwave air plasmas in capillaries at low pressure II. Experimental investigation

    NASA Astrophysics Data System (ADS)

    Stancu, G. D.; Leroy, O.; Coche, P.; Gadonna, K.; Guerra, V.; Minea, T.; Alves, L. L.

    2016-11-01

    This work presents an experimental study of microwave (2.45 GHz excitation frequency) micro-plasmas, generated in dry air (N2 80%: O2 20%) within a small radius silica capillary (345 µm inner radius) at low pressure (300 Pa) and low powers (80–130 W). Experimental diagnostics are performed using optical emission spectroscopy calibrated in absolute intensity. Axial-resolved measurements (50 µm spatial resolution) of atomic transitions N(3p4S)  →  N(3s4P) O(3p5P)  →  O(3s5S) and molecular transitions N2(C,v‧)  →  N2(B,v″) \\text{N}2+ (B,v‧)  →  \\text{N}2+ (X,v″) allow us to obtain, as a function of the coupled power, the absolute densities of N(3p4S), O(3p5P), N2(C), N2(B) and \\text{N}2+ (B), as well as the gas (rotational) temperature (700–1000 K), the vibrational temperature of N2(C,v) (7000–10 000 K) and the excitation temperatures of N2(C) and N2(B) (11 000 K). The analysis of the H β line-width gives an upper limiting value of 1013 cm‑3 for the electron density; its axial variation (4  ×  1011–6  ×  1012 cm‑3) being estimated by solving the wave electrodynamics equations for the present geometry, plasma length and electron–neutral collision frequency. The experimental results were compared with the results from a 0D model, presented in companion paper I [1], which couples the system of rate balance equations for the dominant neutral and charged plasma species to the homogeneous two-term electron Boltzmann equation, taking the measured gas temperature and the estimated electron density as input parameters. Good qualitative agreement is found between the measurements and calculations of the local species densities for various powers and axial positions. The dissociation degree of oxygen is found above 10%. Moreover, both the measurements and calculations show evidence of the non-equilibrium behavior of low-temperature plasmas, with vibrational and excitation

  2. Experimental investigation of aerodynamic devices for wind turbine rotational speed control: Phase II

    SciTech Connect

    Miller, S L

    1996-02-01

    An experimental investigation was undertaken to further evaluate and enhance the performance of an aerodynamic device for wind turbine overspeed protection and power modulation applications. The trailing-edge device, known as the Spoiler-Flap, was examined in detail during wind tunnel tests. The impact of hp length, vent angle, pivot point and chord variations on aerodynamic and hinge moment characteristics were evaluated and a best overall configuration was identified. Based on this effort, a 40% chord device with a 1% hp length and 40 degree vent angle offers improved performance potential for wind turbine applications. This specific configuration appears to offer good suction coefficient performance for both turbine power modulation and overspeed (i.e., aerodynamic braking) applications. Device hinge moment loads improved (compared to other devices investigated) in magnitude and the impact of surface roughness was found to be minimal.

  3. Shock-implanted noble gases. II - Additional experimental studies and recognition in naturally shocked terrestrial materials

    NASA Technical Reports Server (NTRS)

    Bogard, Donald; Horz, Friedrich; Johnson, Pratt

    1989-01-01

    The process by which ambient gases can be implanted into silicates by shocks was investigated by analyzing the noble-gas content of several experimentally and naturally shocked silicate samples. The retentivity of shock-implanted gas during stepwise heating in the laboratory was defined in terms of two parameters, namely, the activation energy for diffusion and the extraction temperature at which 50 percent of the gas is released, both of which correlate with the shock pressure. The experiments indicate that, with increasing shock pressure, gas implantation occurs through an increasing production of microcracks/defects in the silicate lattice. The degree of annealing of these defects control the degree of diffusive loss of implanted gas.

  4. Maximum-likelihood methods in cryo-EM. Part II: application to experimental data

    PubMed Central

    Scheres, Sjors H.W.

    2010-01-01

    With the advent of computationally feasible approaches to maximum likelihood image processing for cryo-electron microscopy, these methods have proven particularly useful in the classification of structurally heterogeneous single-particle data. A growing number of experimental studies have applied these algorithms to study macromolecular complexes with a wide range of structural variability, including non-stoichiometric complex formation, large conformational changes and combinations of both. This chapter aims to share the practical experience that has been gained from the application of these novel approaches. Current insights on how to prepare the data and how to perform two- or three-dimensional classifications are discussed together with aspects related to high-performance computing. Thereby, this chapter will hopefully be of practical use for those microscopists wanting to apply maximum likelihood methods in their own investigations. PMID:20888966

  5. Experimental Studies of the Transition to He II using Hydrogen Seed Particles

    NASA Astrophysics Data System (ADS)

    Paoletti, Matthew S.; Bewley, Gregory; Lathrop, Daniel P.; Sreenivasan, Katepalli

    2006-11-01

    Experimental studies of the phase transition to superfluidity in ^4He using H2 seed particles are presented. A gaseous mixture of hydrogen heavily diluted with helium is injected into the He I phase only a few mK above the lambda transition. The hydrogen gas solidifies into particles typically smaller than a micron, which are imaged by a CMOS camera focused on a thin laser sheet. The system is then evaporatively cooled through the lambda transition. Significant fluctuations and aggregation of the hydrogen particles are observed as the system passes through the phase transition. The fluctuating motions are characterized by particle-tracking. The aggregation is quantified by estimating the particle sizes from the intensity probability distribution function and its evolution. Systematic studies of the effects of quench rapidity and potential causes of these effects are discussed. Bewley G.P., Lathrop D.P., Sreenivasan K.R., Nature 441, 588 (2006)

  6. Sedimentation equilibria of ferrofluids: II. Experimental osmotic equations of state of magnetite colloids.

    PubMed

    Luigjes, Bob; Thies-Weesie, Dominique M E; Erné, Ben H; Philipse, Albert P

    2012-06-20

    The first experimental osmotic equation of state is reported for well-defined magnetic colloids that interact via a dipolar hard-sphere potential. The osmotic pressures are determined from the sedimentation equilibrium concentration profiles in ultrathin capillaries using a low-velocity analytical centrifuge, which is the subject of the accompanying paper I. The pressures of the magnetic colloids, measured accurately to values as low as a few pascals, obey Van 't Hoff's law at low concentrations, whereas at increasing colloid densities non-ideality appears in the form of a negative second virial coefficient. This virial coefficient corresponds to a dipolar coupling constant that agrees with the coupling constant obtained via independent magnetization measurements. The coupling constant manifests an attractive potential of mean force that is significant but yet not quite strong enough to induce dipolar chain formation. Our results disprove van der Waals-like phase behavior of dipolar particles for reasons that are explained. PMID:22617544

  7. Effects of non-specific immunopotentiators in experimental Schistosoma mansoni infection. II. Corynebacterium parvum.

    PubMed

    Teixeira, K M; Coutinho, E M; Abath, F G; Montenegro, S M

    1996-01-01

    The effects of Corynebacterium parvum on host protection, tissue reaction and "in vivo" chemotaxis in Schistosoma mansoni infected mice were studied. The C. parvum was given intraperitoneally using a dose of 0.7 mg, twice a week (for 4 weeks), thirty days before (prophylactic treatment) or after infection (curative treatment). The host protection was evaluated through the recovery of adult worms by liver perfusion and was lower in the prophylactic group as compared to the control group (p = 0.018), resulting in 44% protection. The "in vivo" leukocyte response in both prophylactic and curative groups was higher as compared to the infected/non treated group (p = 0.009 and p = 0.003, respectively). Tissue reactions were described in the experimental and control groups, but there were not remarkable differences among them. The possible biological implications and relevance of the findings for the defensive response of the host and control of schistosomiasis are discussed. PMID:9293078

  8. MarsSedEx I and II: Experimental investigation of gravity effects on sedimentation on Mars

    NASA Astrophysics Data System (ADS)

    Kuhn, N. J.; Kuhn, B.; Gartmann, A.

    2014-12-01

    Sorting of sedimentary rocks is a proxy for the environmental conditions at the time of deposition, in particular the runoff that moved and deposited the material forming the rocks. Settling of sediment is strongly influenced by the gravity of a planetary body. As a consequence, sorting of a sedimentary rock varies with gravity for a given depth and velocity of surface runoff. Theoretical considerations for spheres indicate that sorting is less uniform on Mars than on Earth for runoff of identical depth. The effects of gravity on flow hydraulics limit the use of common, semi-empirical models developed to simulate particle settling in terrestrial environments, on Mars. Assessing sedimentation patterns on Mars, aimed at identifying strata potentially hosting traces of life, is potentially affected by such uncertainties. Using first-principle approaches, e.g. through Computational Fluid Dynamics, for calculating settling velocities on other planetary bodies requires a large effort and is limited by the values of boundary conditions, e.g. the shape of the particle. The degree of uncertainty resulting from the differences in gravity on Earth and Mars was therefore tested during three reduced-gravity flights, the MarsSedEx I and II missions, conducted in November 2012 and 2013. Nine types of sediment, ranging in size, shape and density were tested in custom-designed settling tubes during parabolas of Martian gravity lasting 20 to 25 seconds. Based on the observed settling velocities, the uncertainties of empirical relationships developed on Earth to assess particle settling on Mars are discussed. In addition, the potential effects of reduced gravity on patterns of erosion, transport and sorting of sediment, including the implications for identifying strata bearing traces of past life on are examined.

  9. Peripapillary and posterior scleral mechanics--part II: experimental and inverse finite element characterization.

    PubMed

    Girard, Michaël J A; Downs, J Crawford; Bottlang, Michael; Burgoyne, Claude F; Suh, J-K Francis

    2009-05-01

    The posterior sclera likely plays an important role in the development of glaucoma, and accurate characterization of its mechanical properties is needed to understand its impact on the more delicate optic nerve head--the primary site of damage in the disease. The posterior scleral shells from both eyes of one rhesus monkey were individually mounted on a custom-built pressurization apparatus. Intraocular pressure was incrementally increased from 5 mm Hg to 45 mm Hg, and the 3D displacements were measured using electronic speckle pattern interferometry. Finite element meshes of each posterior scleral shell were reconstructed from data generated by a 3D digitizer arm (shape) and a 20 MHz ultrasound transducer (thickness). An anisotropic hyperelastic constitutive model described in a companion paper (Girard, Downs, Burgoyne, and Suh, 2009, "Peripapillary and Posterior Scleral Mechanics--Part I: Development of an Anisotropic Hyperelastic Constitutive Model," ASME J. Biomech. Eng., 131, p. 051011), which includes stretch-induced stiffening and multidirectional alignment of the collagen fibers, was applied to each reconstructed mesh. Surface node displacements of each model were fitted to the experimental displacements using an inverse finite element method, which estimated a unique set of 13 model parameters. The predictions of the proposed constitutive model matched the 3D experimental displacements well. In both eyes, the tangent modulus increased dramatically with IOP, which indicates that the sclera is mechanically nonlinear. The sclera adjacent to the optic nerve head, known as the peripapillary sclera, was thickest and exhibited the lowest tangent modulus, which might have contributed to the uniform distribution of the structural stiffness for each entire scleral shell. Posterior scleral deformation following acute IOP elevations appears to be nonlinear and governed by the underlying scleral collagen microstructure as predicted by finite element modeling. The

  10. Photodissociation of methyl chloride and methyl bromide in the atmosphere

    NASA Technical Reports Server (NTRS)

    Robbins, D. E.

    1976-01-01

    Methyl chloride (CH3Cl) and methyl bromide (CH3Br) have been suggested to be significant sources of the stratospheric halogens. The breakup of these compounds in the stratosphere by photodissociation or reaction with OH releases halogen atoms which catalytically destroy ozone. Experimental results are presented for ultraviolet photoabsorption cross sections of CH3Cl and CH3Br. Calculations are presented of loss rates for the methyl halides due to photodissociation and reaction with OH and of mixing ratios of these species in the stratosphere.

  11. Continuous fixed bed adsorption of Cu(II) by halloysite nanotube-alginate hybrid beads: an experimental and modelling study.

    PubMed

    Wang, Yanyan; Zhang, Xiang; Wang, Qiuru; Zhang, Bing; Liu, Jindun

    2014-01-01

    We used natural resources of halloysite nanotubes and alginate to prepare a novel porous adsorption material of organic-inorganic hybrid beads. The adsorption behaviour of Cu(II) onto the hybrid beads was examined by a continuous fixed bed column adsorption experiment. Meanwhile, the factors affecting the adsorption capacity such as bed height, influent concentration and flow rate were investigated. The adsorption capacity (Q0) reached 74.13 mg/g when the initial inlet concentration was 100 mg/L with a bed height of 12 cm and flow rate of 3 ml/min. The Thomas model and bed-depth service time fitted well with the experimental data. In the regeneration experiment, the hybrid beads retained high adsorption capacity after three adsorption-desorption cycles. Over the whole study, the new hybrid beads showed excellent adsorption and regeneration properties as well as favourable stability. PMID:25051464

  12. Structural and spectral properties of a zinc(II) coordination polymer: a combined experimental and theoretical study.

    PubMed

    Hao, Jin-Ming; Li, Guang-Yue; Li, Yue-Hua; Cui, Guang Hua

    2014-10-15

    A novel 1D zinc(II) coordination polymer [Zn(bbbm)Cl2]n (where bbbm=1,4-bis(N-benzimidazolyl)butane) was synthetized by ZnCl2 and bbbm ligand under hydrothermal conditions, and its structural and spectral properties were studied by both experimental and theoretical techniques. The center zinc(II) ion displays four-coordinated in a tetrahedral geometry by two chloride anions and two N atoms of distinct bbbm ligands. Adjacent chains are further connected into a 2D layer structure through π-π stacking interactions. Vibrational frequencies of [Zn(bbbm)Cl2]n have been calculated using DFT/B3LYP/TZVP method, and well reproduced IR data. Furthermore, the vertical excitation energies from time-dependent DFT calculation confirmed that the fluorescent peaks at 385nm and 450nm could respectively be assigned to the π→π(*) transition within the bbbm ligands and π→n transition from chloride anion to bbbm ligand.

  13. Photoinactivation of Photosystem II in wild-type and chlorophyll b-less barley leaves: which mechanism dominates depends on experimental circumstances.

    PubMed

    He, Jie; Yang, Wenquan; Qin, Lin; Fan, Da-Yong; Chow, Wah Soon

    2015-12-01

    Action spectra of photoinactivation of Photosystem II (PS II) in wild-type and chlorophyll b-less barley leaf segments were obtained. Photoinactivation of PS II was monitored by the delivery of electrons from PS II to PS I following single-turnover flashes superimposed on continuous far-red light, the time course of photoinactivation yielding a rate coefficient k i. Susceptibility of PS II to photoinactivation was quantified as the ratio of k i to the moderate irradiance (I) of light at each selected wavelength. k i/I was very much higher in blue light than in red light. The experimental conditions permitted little excess light energy absorbed by chlorophyll (not utilized in photochemical conversion or dissipated in controlled photoprotection) that could lead to photoinactivation of PS II. Therefore, direct absorption of light by Mn in PS II, rather than by chlorophyll, was more likely to have initiated the much more severe photoinactivation in blue light than in red light. Mutant leaves were ca. 1.5-fold more susceptible to photoinactivation than the wild type. Neither the excess-energy mechanism nor the Mn mechanism can explain this difference. Instead, the much lower chlorophyll content of mutant leaves could have exerted an exacerbating effect, possibly partly due to less mutual shading of chloroplasts in the mutant leaves. In general, which mechanism dominates depends on the experimental conditions.

  14. Is there chaos in the brain? II. Experimental evidence and related models.

    PubMed

    Korn, Henri; Faure, Philippe

    2003-09-01

    The search for chaotic patterns has occupied numerous investigators in neuroscience, as in many other fields of science. Their results and main conclusions are reviewed in the light of the most recent criteria that need to be satisfied since the first descriptions of the surrogate strategy. The methods used in each of these studies have almost invariably combined the analysis of experimental data with simulations using formal models, often based on modified Huxley and Hodgkin equations and/or of the Hindmarsh and Rose models of bursting neurons. Due to technical limitations, the results of these simulations have prevailed over experimental ones in studies on the nonlinear properties of large cortical networks and higher brain functions. Yet, and although a convincing proof of chaos (as defined mathematically) has only been obtained at the level of axons, of single and coupled cells, convergent results can be interpreted as compatible with the notion that signals in the brain are distributed according to chaotic patterns at all levels of its various forms of hierarchy. This chronological account of the main landmarks of nonlinear neurosciences follows an earlier publication [Faure, Korn, C. R. Acad. Sci. Paris, Ser. III 324 (2001) 773-793] that was focused on the basic concepts of nonlinear dynamics and methods of investigations which allow chaotic processes to be distinguished from stochastic ones and on the rationale for envisioning their control using external perturbations. Here we present the data and main arguments that support the existence of chaos at all levels from the simplest to the most complex forms of organization of the nervous system. We first provide a short mathematical description of the models of excitable cells and of the different modes of firing of bursting neurons (Section 1). The deterministic behavior reported in giant axons (principally squid), in pacemaker cells, in isolated or in paired neurons of Invertebrates acting as coupled

  15. NRPD4, a Protein Related to the RPB4 Subunit of RNA Polymerase II, is a Component of RNA Polymerases IV and V and is Required for RNA-directed DNA methylation

    SciTech Connect

    He, Xin-Jian; Hsu, Yi-Feng; Pontes, Olga; Zhu, Jianhua; Lu, Jian; Bressan, Ray A.; Pikaard, Craig S.; Wang, Co-Shine; Zhu, Jian-Kang

    2009-01-01

    RNA-directed DNA methylation (RdDM) is an RNAi-based mechanism for establishing transcriptional gene silencing in plants. The plant-specific RNA polymerases IV and V are required for the generation of 24-nucleotide (nt) siRNAs and for guiding sequence-specific DNA methylation by the siRNAs, respectively. However, unlike the extensively studied multisubunit Pol II, our current knowledge about Pol IV and Pol V is restricted to only the two largest subunits NRPD1a/NRPD1 and NRPD1b/NRPE1 and the one second-largest subunit NRPD2a. It is unclear whether other subunits may be required for the functioning of Pol IV and Pol V in RdDM. From a genetic screen for second-site suppressors of the DNA demethylase mutant ros1, we identified a new component (referred to as RDM2) as well as seven known components (NRPD1, NRPE1, NRPD2a, AGO4, HEN1, DRD1, and HDA6) of the RdDM pathway. The differential effects of the mutations on two mechanistically distinct transcriptional silencing reporters suggest that RDM2, NRPD1, NRPE1, NRPD2a, HEN1, and DRD1 function only in the siRNA-dependent pathway of transcriptional silencing, whereas HDA6 and AGO4 have roles in both siRNA-dependent and -independent pathways of transcriptional silencing. In the rdm2 mutants, DNA methylation and siRNA accumulation were reduced substantially at loci previously identified as endogenous targets of Pol IV and Pol V, including 5S rDNA, MEA-ISR, AtSN1, AtGP1, and AtMU1. The amino acid sequence of RDM2 is similar to that of RPB4 subunit of Pol II, but we show evidence that RDM2 has diverged significantly from RPB4 and cannot function in Pol II. An association of RDM2 with both NRPD1 and NRPE1 was observed by coimmunoprecipitation and coimmunolocalization assays. Our results show that RDM2/NRPD4/NRPE4 is a new component of the RdDM pathway in Arabidopsis and that it functions as part of Pol IV and Pol V.

  16. Advanced automation concepts applied to Experimental Breeder Reactor-II startup

    SciTech Connect

    Berkan, R.C.; Upadhyaya, B.R.; Bywater, R.L. . Dept. of Nuclear Engineering); Kisner, R.A. )

    1991-08-01

    The major objective of this work is to demonstrate through simulations that advanced liquid-metal reactor plants can be operated from low power by computer control. Development of an automatic control system with this objective will help resolve specific issues and provide proof through demonstration that automatic control for plant startup is feasible. This paper presents an advanced control system design for startup of the Experimental Breeder Reactor-2 (EBR-2) located at Idaho Falls, Idaho. The design incorporates recent methods in nonlinear control with advanced diagnostics techniques such as neural networks to form an integrated architecture. The preliminary evaluations are obtained in a simulated environment by a low-order, valid nonlinear model. Within the framework of phase 1 research, the design includes an inverse dynamics controller, a fuzzy controller, and an artificial neural network controller. These three nonlinear control modules are designed to follow the EBR-2 startup trajectories in a multi-input/output regime. They are coordinated by a supervisory routine to yield a fault-tolerant, parallel operation. The control system operates in three modes: manual, semiautomatic, and fully automatic control. The simulation results of the EBR-2 startup transients proved the effectiveness of the advanced concepts. The work presented in this paper is a preliminary feasibility analysis and does not constitute a final design of an automated startup control system for EBR-2. 14 refs., 43 figs.

  17. Zernike test. I - Analytical aspects. II - Experimental aspects. [interferometric phase error test

    NASA Technical Reports Server (NTRS)

    Golden, L. J.

    1977-01-01

    The Zernike phenomenon is interpreted in general interferometric terms to gain insight into the optimum design of disks suitable for a particular experimental situation. The design of Zernike disks for measuring small low-order aberrations is considered and evaluated; optimum parameters for disks 2, 3, 4, and 5 microns in radius are determined for an f/12 large-space-telescope system with an obscuration ratio of 0.4 at 0.6 micron. It is shown that optimization in this case provides sensitivities of better than one hundredth of a wavelength for the measurement of low-order aberrations. The procedure for manufacturing a Zernike disk is then described in detail, and results are reported for tests of a laboratory Zernike figure sensor containing a disk manufactured according to this procedure. In the tests, a laboratory wavefront-error simulator was used to introduce small aberration ranges, measurements of the changes in reimaged pupil intensity introduced by the disk were made for several aberration settings, and the measured changes were compared with the values predicted by the interferometric theory of Zernike tests. The results are found to agree within an error of one two-hundredth of a wavelength.

  18. Comparison of chemical and thermal protein denaturation by combination of computational and experimental approaches. II

    NASA Astrophysics Data System (ADS)

    Wang, Qian; Christiansen, Alexander; Samiotakis, Antonios; Wittung-Stafshede, Pernilla; Cheung, Margaret S.

    2011-11-01

    Chemical and thermal denaturation methods have been widely used to investigate folding processes of proteins in vitro. However, a molecular understanding of the relationship between these two perturbation methods is lacking. Here, we combined computational and experimental approaches to investigate denaturing effects on three structurally different proteins. We derived a linear relationship between thermal denaturation at temperature Tb and chemical denaturation at another temperature Tu using the stability change of a protein (ΔG). For this, we related the dependence of ΔG on temperature, in the Gibbs-Helmholtz equation, to that of ΔG on urea concentration in the linear extrapolation method, assuming that there is a temperature pair from the urea (Tu) and the aqueous (Tb) ensembles that produces the same protein structures. We tested this relationship on apoazurin, cytochrome c, and apoflavodoxin using coarse-grained molecular simulations. We found a linear correlation between the temperature for a particular structural ensemble in the absence of urea, Tb, and the temperature of the same structural ensemble at a specific urea concentration, Tu. The in silico results agreed with in vitro far-UV circular dichroism data on apoazurin and cytochrome c. We conclude that chemical and thermal unfolding processes correlate in terms of thermodynamics and structural ensembles at most conditions; however, deviations were found at high concentrations of denaturant.

  19. Marine molluscs in environmental monitoring. II. Experimental exposure to selected pollutants

    NASA Astrophysics Data System (ADS)

    Bresler, Vladimir; Mokady, Ofer; Fishelson, Lev; Feldstein, Tamar; Abelson, Avigdor

    2003-10-01

    In an effort to establish biomonitoring programmes for routine and emergency monitoring of littoral marine habitats, organismal responses are examined in two ways: firstly, in controlled, laboratory studies, where the response may be accurately characterized; secondly, in field-collected specimens, with the hope of obtaining evidence regarding disturbances such as the ones caused by anthropogenic pollution. In many cases, there is a gap between the two types of studies, and different species and experimental and/or analytical procedures are used. In a series of recent studies, we have examined responses of field-collected molluscs, and interpreted our findings with respect to pollution. Here, we report a complementary study, in which molluscs collected from reference and polluted sites were exposed to cadmium or DDT under controlled laboratory conditions. Using fluorescent probes and microfluorometry, we examined the effect of these pollutants on paracellular permeability, lysosomal stability and metabolic status of mitochondria. Our findings indicate that molluscs from polluted sites are less affected, showing significantly smaller alterations in all examined parameters. These findings are in line with previous results showing higher levels of activity of cellular defence mechanisms in molluscs collected from polluted sites. Taken together, the results may be used to establish a reliable biomonitoring system. The sensitivity of the suggested methodology is also expected to qualify such a system for early warning.

  20. Experimental studies of alunite: II. Rates of alunite-water alkali and isotope exchange

    USGS Publications Warehouse

    Stoffregen, R.E.; Rye, R.O.; Wasserman, M.D.

    1994-01-01

    Rates of alkali exchange between alunite and water have been measured in hydrothermal experiments of 1 hour to 259 days duration at 150 to 400??C. Examination of run products by scanning electron microscope indicates that the reaction takes place by dissolution-reprecipitation. This exchange is modeled with an empirical rate equation which assumes a linear decrease in mineral surface area with percent exchange (f) and a linear dependence of the rate on the square root of the affinity for the alkali exchange reaction. This equation provides a good fit of the experimental data for f = 17% to 90% and yields log rate constants which range from -6.25 moles alkali m-2s-1 at 400??C to - 11.7 moles alkali m-2s-1 at 200??C. The variation in these rates with temperature is given by the equation log k* = -8.17(1000/T(K)) + 5.54 (r2 = 0.987) which yields an activation energy of 37.4 ?? 1.5 kcal/mol. For comparison, data from O'Neil and Taylor (1967) and Merigoux (1968) modeled with a pseudo-second-order rate expression give an activation energy of 36.1 ?? 2.9 kcal/mol for alkali-feldspar water Na-K exchange. In the absence of coupled alkali exchange, oxygen isotope exchange between alunite and water also occurs by dissolution-reprecipitation but rates are one to three orders of magnitude lower than those for alkali exchange. In fine-grained alunites, significant D-H exchange occurs by hydrogen diffusion at temperatures as low as 100??C. Computed hydrogen diffusion coefficients range from -15.7 to -17.3 cm2s-1 and suggest that the activation energy for hydrogen diffusion may be as low as 6 kcal/mol. These experiments indicate that rates of alkali exchange in the relatively coarse-grained alunites typical of hydrothermal ore deposits are insignificant, and support the reliability of K-Ar age data from such samples. However, the fine-grained alunites typical of low temperature settings may be susceptible to limited alkali exchange at surficial conditions which could cause

  1. Clusters of DNA damage induced by ionizing radiation: formation of short DNA fragments. II. Experimental detection

    NASA Technical Reports Server (NTRS)

    Rydberg, B.; Chatterjee, A. (Principal Investigator)

    1996-01-01

    The basic 30-nm chromatin fiber in the mammalian cell consists of an unknown (possibly helical) arrangement of nucleosomes, with about 1.2 kb of DNA per 10-nm length of fiber. Track-structure considerations suggest that interactions of single delta rays or high-LET particles with the chromatin fiber might result in the formation of multiple lesions spread over a few kilobases of DNA (see the accompanying paper: W.R. Holley and A. Chatterjee, Radiat. Res. 145, 188-199, 1996). In particular, multiple DNA double-strand breaks and single-strand breaks may form. To test this experimentally, primary human fibroblasts were labeled with [3H]thymidine and exposed at 0 degrees C to X rays or accelerated nitrogen or iron ions in the LET range of 97-440 keV/microns. DNA was isolated inside agarose plugs and subjected to agarose gel electrophoresis under conditions that allowed good separation of 0.1-2 kb size DNA. The bulk of DNA remained in the well or migrated only a small distance into the gel. It was found that DNA fragments in the expected size range were formed linearly with dose with an efficiency that increased with LET. A comparison of the yield of such fragments with the yield of total DNA double-strand breaks suggests that for the high-LET ions a substantial proportion (20-90%) of DNA double-strand breaks are accompanied within 0.1-2 kb by at least one additional DNA double-strand break. It is shown that these results are in good agreement with theoretical calculations based on treating the 30-nm chromatin fiber as the target for ionizing particles. Theoretical considerations also predict that the clusters will contain numerous single-strand breaks and base damages. It is proposed that such clusters be designated "regionally multiply damaged sites." Postirradiation incubation at 37 degrees C resulted in a decline in the number of short DNA fragments, suggesting a repair activity. The biological significance of regionally multiply damaged sites is presently unknown.

  2. [Bis(quinolin-2-ylcarbon-yl)amido-κ(3) N,N',N'']bromido-(N,N-di-methyl-formamide-κO)copper(II).

    PubMed

    Faizi, Md Serajul Haque; Sen, Pratik

    2014-06-01

    In the mononuclear title complex, [CuBr(C20H12N3O2)(C3H7NO)], synthesized from the quinoline-derived reduced Schiff base 4-(quinolin-2-ylmeth-yl)amino-phenol, the coordination geometry around Cu(2+) is distorted square-pyramidal, comprising a bromide anion at the apex [Cu-Br = 2.4671 (5) Å]. The base of the pyramid is built up from one di-methyl-formamide O-atom donor [Cu-O = 2.078 (2) Å] and three N-atom donors from the monoanionic, tridentate bis-(quinolin-2-ylcarbon-yl)di-imide ligand [Cu-Ndi-imide = 1.941 (3) Å, and Cu-Nquinol-yl = 2.060 (3) and 2.049 (3) Å]. An intra-molecular C-H⋯O occurs. In the crystal, weak methyl and aromatic C-H⋯Br and formyl C-H⋯Ocarbon-yl hydrogen-bonding inter-actions generate an overall layered structure lying parallel to (001). PMID:24940197

  3. {(E)-4-Hy­droxy-N′-[phen­yl(pyridin-2-yl-κN)methyl­idene]benzohydrazide-κ2 N′,O}bis­(nitrato-κ2 O,O′)copper(II)

    PubMed Central

    Bikas, Rahman; Sattari, Farhad; Notash, Behrouz

    2012-01-01

    In the title compound, [Cu(NO3)2(C19H15N3O2)], the coordination geometry around the CuII ion can be described as distorted square-pyramidal, with two N atoms and one O atom from an (E)-4-hy­droxy-N′-[phen­yl(pyridin-2-yl)methyl­ene]benzohydrazide ligand and one nitrate O atom in the basal plane and one nitrate O atom at the apical site. The other two nitrate O atoms also bind to the Cu atom with long Cu—O distances [2.607 (4) and 2.853 (5) Å]. The crystal packing is stabilized by inter­molecular N—H⋯O and O—H⋯O hydrogen bonds. PMID:22346817

  4. Effect of (3,5,6-trimethylpyrazin-2-yl)methyl 2-[4-(2-methylpropyl)phenyl]propanoate (ITE), a newly developed anti-inflammatory drug, on type II collagen-induced arthritis in mice.

    PubMed

    Ma, Tao; Cao, Ying-Lin; Xu, Bei-Bei; Zhou, Xiao-Mian

    2004-06-01

    The effect of (3,5,6-trimethylpyrazin-2-yl)methyl 2-[4-(2-methylpropyl)phenyl]propanoate (ITE) on type II collagen (CII)-induced arthritis in mice was studied. Mice were immunized twice with CII, ITE being given orally once a day for 40 d after the 1st immunization. Clinical assessment showed that ITE had no effect on the day of onset of arthritis but did lowered the incidence rate of arthritis and the arthritis score. And ITE had a marked suppressive effect on the mouse hind paw edema induced by CII. ITE suppressed the delayed-type mouse ear skin reaction to CII but had no effect on the level of serum anti-CII antibodies. These results suggest that ITE inhibits the development of CII-induced arthritis in mice by suppressing delayed-type hypersensitivity to CII.

  5. Experimental study of the autoignition of C{sub 8}H{sub 16}O{sub 2} ethyl and methyl esters in a motored engine

    SciTech Connect

    Zhang, Yu.; Boehman, Andre L.

    2010-03-15

    Autoignition of two biodiesel surrogates, methyl heptanoate and ethyl hexanoate, was studied in a motored CFR engine at an equivalence ratio of 0.25 and an intake temperature of 155 C. The engine compression ratio was gradually increased from the lowest point (4.43) to the point where significant high temperature heat release (HTHR) occurred. Within the test range of this work, both of the two esters exhibited evident cool flame behavior. At the same compression ratio, methyl heptanoate was observed to have both an earlier onset and a higher magnitude of low temperature heat release (LTHR) than ethyl hexanoate, indicating that methyl heptanoate is more reactive in the low temperature region than ethyl hexanoate. GC-MS analyses of the reaction intermediates from the oxidation of the two esters showed that the alkyl chain of fatty acid esters experiences the typical paraffin-like low temperature oxidation sequence. Based on the observations from GC-MS analyses, major low temperature oxidation pathways of ethyl hexanoate are proposed in this work. Also, it is observed that the abstraction of H-atoms on the {alpha}-carbon of the ester carbonyl group plays an important role in the oxidation of fatty acid esters. In addition, the identification of hexanoic acid among the reaction intermediates from low temperature oxidation of ethyl hexanaoate together with the observation of more fuel carbon being converted to C{sub 2}H{sub 4} during ethyl hexanoate oxidation than during methyl heptanoate oxidation provide evidence for the existence of the six-centered unimolecular elimination reaction during low temperature oxidation of ethyl esters. (author)

  6. Synthesis, spectroscopic properties, crystal structure and density functional studies of Cu(II) complex with 2-((dehydroabietylamine)methyl)-6-methoxyphenol

    NASA Astrophysics Data System (ADS)

    Liu, Bao-Yu; Liu, Zheng; Han, Guo-Cheng; Li, Yan-Hong

    2010-06-01

    The metal complex of CuL 2 (L = 2-((dehydroabietylamine)methyl)-6-methoxyphenol) has been synthesized and characterized by spectral method (IR), elemental analysis, thermal analysis (TG, DTG) and single crystal X-ray diffraction techniques. Molecular geometry from X-ray experiment of the title compound in the ground-state has been compared using the density functional method (B3LYP) with LANL2DZ basis set. UV-vis spectra has been measured and DFT calculations at B3LYP/LANL2DZ level of theory proved that the electronic spectra of CuL 2 was attributed to intra-complex electronic transitions as well as d- d electronic transitions. Besides, Mulliken charge analysis, natural bond orbitals (NBO), frontier molecular orbitals (FMO) were performed at B3LYP/LANL2DZ level of theory.

  7. Azaindole N-methyl hydroxamic acids as HIV-1 integrase inhibitors-II. The impact of physicochemical properties on ADME and PK.

    PubMed

    Tanis, Steven P; Plewe, Michael B; Johnson, Ted W; Butler, Scott L; Dalvie, Deepak; DeLisle, Dorothy; Dress, Klaus R; Hu, Qiyue; Huang, Buwen; Kuehler, Jon E; Kuki, Atsuo; Liu, Wen; Peng, Qinghai; Smith, Graham L; Solowiej, Jim; Tran, Khanh T; Wang, Hai; Yang, Anle; Yin, Chunfeng; Yu, Xiaoming; Zhang, Junhu; Zhu, Huichun

    2010-12-15

    HIV-1 integrase is one of three enzymes encoded by the HIV genome and is essential for viral replication, and HIV-1 IN inhibitors have emerged as a new promising class of therapeutics. Recently, we reported the discovery of azaindole hydroxamic acids that were potent inhibitors of the HIV-1 IN enzyme. N-Methyl hydroxamic acids were stable against oxidative metabolism, however were cleared rapidly through phase 2 glucuronidation pathways. We were able to introduce polar groups at the β-position of the azaindole core thereby altering physical properties by lowering calculated log D values (c Log D) which resulted in attenuated clearance rates in human hepatocytes. Pharmacokinetic data in dog for representative compounds demonstrated moderate oral bioavailability and reasonable half-lives. These ends were accomplished without a large negative impact on enzymatic and antiviral activity, thus suggesting opportunities to alter clearance parameters in future series.

  8. Dimeric and polymeric mercury(II) complexes of 1-methyl-1,2,3,4-tetrazole-5-thiol: Synthesis, crystal structure, spectroscopic characterization, and thermal analyses

    NASA Astrophysics Data System (ADS)

    Taheriha, Mohammad; Ghadermazi, Mohammad; Amani, Vahid

    2016-03-01

    Two-dimensional coordination polymer of [Hg(μ3-mmtz)2]n (1) and centrosymmetric dinuclear complexes of {[H2en][Hg2(mmtz)4(μ-Br)2]} (2) and {[H2en][Hg2(mmtz)4(μ-I)2]} (3) (where Hmmtz is 1-methyl-1,2,3,4-tetrazole-5-thiol and en is ethylene diamine) were synthesized from the reaction of Hmmtz and en with HgCl2, HgBr2 and HgI2, respectively, in CH3OH. Complex 1 was also synthesized from the reaction of Hmmtz and en with HgX2 (X = OAc and SCN) in CH3OH. These three complexes were thoroughly characterized by elemental analysis (CHN), thermal gravimetric analysis (TGA), differential thermal analyses (DTA), infrared, UV-vis, 1H NMR, and luminescence spectroscopy, and their structures were determined by single-crystal X-ray diffraction.

  9. Bis[(di­methyl­phosphor­yl)methan­amin­ium] tetra­chlorido­palladate(II)

    PubMed Central

    Reiss, Guido J.

    2013-01-01

    In the crystal structure of the title compound, (C3H11NOP)2[PdCl4], (di­methyl­phosphor­yl)methanaminium (dpmaH+) cations are connected head-to-tail by strong N—H⋯O hydrogen bonds, forming inversion-related cyclic dimers. The square-planar [PdCl4]2− counter-dianion is located about a center of inversion. The dications and the [PdCl4]2− dianions are connected by medium–strong N—H⋯Cl hydrogen bonds, forming zigzag chains parallel to [001]. Somewhat weaker N—H⋯Cl hydrogen bonds connect the chains into a three-dimensional network. PMID:24454042

  10. Palladium(II) Complexes Containing Mixed Nitrogen-Sulphur Donor Ligands: Interaction of [Pd(Methionine Methyl Ester)(H2O)2]2+ with Biorelevant Ligands

    PubMed Central

    Shoukry, Mohamed M.; Ezzat, Sameya M. T.

    2014-01-01

    Pd(MME)Cl2 complex (MME = methionine methyl ester) was synthesised and characterized by physicochemical measurements. The reaction of [Pd(MME)(H2O)2]2+ with amino acids, peptides, or dicarboxylic acids was investigated at 25°C and 0.1 M ionic strength. Amino acids and dicarboxylic acids form 1 : 1 complexes. Peptides form both 1 : 1 complexes and the corresponding deprotonated amide species. The stability of the complexes formed was determined and the binding centres of the ligands were assigned. Effect of solvent on the stability constant of Pd(MME)-CBDCA complex, taken as a representative example, shows that the complex is more favoured in a medium of low dielectric constant. The concentration distribution diagrams of the complexes were evaluated. PMID:25214826

  11. [Experimental Research of Hg (II) Removal from Aqueous Solutions of HgCl2 with Nano-TiO2].

    PubMed

    Zhou, Xiong; Zhang, Jin-yang; Wang, Ding-yong; Qin, Cai-qing; Xu, Feng; Luo Cheng-zhong; Yang, Xi

    2016-01-15

    Mercury removal from aqueous solutions of HgCl2 was studied by indoor simulation experiments, and the effects of three different diameter of particles of Nano-TiO2 ( Nano-Titanium Dioxide) at different dosage, pH, adsorption time and the initial concentration of Hg2+ on the mercury adsorption from simulated wastewater were investigated. The single factor experiments showed that the optimal conditions were: 7.5 g x L(-1) of 5 nm TiO2 or 2.0 g x L(-1) of 100 nm TiO2, pH 8.0, initial concentration of Hg2+ 15 x mg x L(-1) adsorption time 5 min, and under these conditions the adsorption rates reached 99.5% and 99.3%, relatively. When the content of 25 nm TiO2 was 10 g x L(-1), and the other conditions were pH 8.0, initial concentration of Hg2+ 15 mg x L(-1), adsorption time 60 min, the adsorption rate was 62.8%. The Hg(II) removal effects of the TiO2 particles with different diameters followed the order of 100 nm TiO2 > 5 nm TiO2 > 25 nm TiO2. Component adsorption results showed that the 5 nm TiO2 component adsorption effect was superior to its single adsorption effect, while there was little difference between 100 nm TiO2 component adsorption effect and its single adsorption effect. The results of orthogonal experiments indicated that the influencing factors of the adsorption rate followed the order of pH > the initial concentration of Hg2+ > time > dosage. The optimal experiment scheme was: pH 8.0, a dosage of 100 nm Nano-TiO2 of 2.0 g x L(-1) an initial Hg2+ concentration of 25 mg x L(-1) and adsorption time of 10 min. Under the experimental conditions, the maximum adsorption rate reached 99.9%, at the same time, the equilibrium concentration of Hg(II) was 0.033 mg x L(-1) < 0.05 mg x L(-1), below the current enterprise rules of water pollutants in mercury emissions limits. In addition, the maximum adsorptive capacity was 26.95 mg x g(-1). The adsorption isotherm was in line with the Langmuir isotherm equation, indicating that the Hg(II) uptake by 100 nm Nano-TiO2

  12. catena-Poly[[[tetra-kis-(4-methyl-pyridine-κN)copper(II)]-μ-sulfato-κO:O'] 4.393-hydrate].

    PubMed

    Alam, Naveed; Shahid, Muhammad; Mazhar, Muhammad; Al-Jassabi, Saad; Zeller, Matthias; Hunter, Allen D

    2011-01-01

    The structure of the title compound, {[Cu(SO(4))(C(6)H(7)N)(4)]·4.393H(2)O}(n), consists of Cu(2+) ions surrounded in a square-planar fashion by 4-methyl-pyridine ligands, forming two crystallographically independent Cu{H(3)C(C(5)H(4)N)}(4) units that are both located on crystallographic inversion centers. The Cu(4-methyl-pyridine)(4) units are, in turn, connected with each other via bridging sulfate anions, leading to the formation of infinite [Cu{H(3)C(C(5)H(4)N)}(4)SO(4)](n) zigzag chains along [001]. The completed coordination spheres of the Cu(2+) ions are slightly distorted octa-hedral. The axial Cu-O bonds are elongated [average length = 2.42 (4) Å] compared to the equatorial Cu-N bonds [average length = 2.043 (2) Å]. The inter-stitial space between the chains is filled with uncoordinated water mol-ecules that consolidate the structure through O-H⋯O hydrogen bonding. One of the five crystallographically independent solvent water mol-ecules is partially occupied with an occupancy factor of 0.396 (4). Due to hydrogen bonding between symmetry-equivalent water mol-ecules across inversion centers, several of the water H atoms are disordered in 1:1 ratios over mutually exclusive positions. The crystal under investigation was found to be non-merohedrally twinned in a 0.789 (1):0.211 (1) ratio by a 180° rotation around the reciprocal b axis. PMID:21522297

  13. DNA-binding and molecular mechanics modelling studies of the bulky chiral platinum(II) complex [PtCl(2)(mepyrr)] (mepyrr=N-methyl-2-aminomethylpyrrolidine).

    PubMed

    Diakos, Connie I; Fenton, Ronald R; Hambley, Trevor W

    2006-12-01

    Detailed studies were carried out on the binding of the enantiomers of [PtCl(2)(mepyrr)] (mepyrr=N-methyl-2-aminomethylpyrrolidine) to dG, d(GpG) and a 52-mer oligonucleotide. The pyrrolidine ligand structure was found to be neither sufficiently rigid nor bulky to enforce a single chirality at the exocyclic amine site in this complex, resulting in the presence of diastereomers that complicated the binding studies. Reaction of the (GpG) dinucleotide with R- and S-[PtCl(2)(mepyrr)] resulted in formation of four [Pt{d(GpG)}(mepyrr)] isomers for each enantiomer as a consequence of the existence of two orientational isomers and two diastereomers. These isomers formed in different amounts most likely as a consequence of the unequal formation of the diastereomers together with stereoselectivity induced by interactions between the dinucleotide and the mepyrr ligand. The [PtCl(2)(mepyrr)] complexes displayed stereoselectivity and enantioselectivity in their reactions with a 52-mer duplex designed to allow formation of only GpG intrastrand adducts. All four bifunctional adducts formed for each enantiomer, providing further evidence of the lack of directing ability of the ligand in formation of the 1,2-intrastrand adduct. Significant amounts of monofunctional species remained in these assays suggesting that the introduction of the methyl substituent to the exocyclic amine inhibited ring-closure to the bifunctional adduct. This was not sufficient to achieve enantiospecificity, but in the case of the R-enantiomer, one of the bifunctional adducts formed in only small amounts. PMID:17083976

  14. Heat Transfer Measurements of the First Experimental Layer of the Fire II Reentry Vehicle in Expansion Tubes

    NASA Astrophysics Data System (ADS)

    Capra, B. R.; Morgan, R. G.; Leyland, P.

    2005-02-01

    The present study focused on simulating a trajectory point towards the end of the first experimental heatshield of the FIRE II vehicle, at a total flight time of 1639.53s. Scale replicas were sized according to binary scaling and instrumented with thermocouples for testing in the X1 expansion tube, located at The University of Queensland. Correlation of flight to experimental data was achieved through the separation, and independent treatment of the heat modes. Preliminary investigation indicates that the absolute value of radiant surface flux is conserved between two binary scaled models, whereas convective heat transfer increases with the length scale. This difference in the scaling techniques result in the overall contribution of radiative heat transfer diminishing to less than 1% in expansion tubes from a flight value of approximately 9-17%. From empirical correlation's it has been shown that the St √ Re number decreases, under special circumstances, in expansion tubes by the percentage radiation present on the flight vehicle. Results obtained in this study give a strong indication that the relative radiative heat transfer contribution in the expansion tube tests is less than that in flight, supporting the analysis that the absolute value remains constant with binary scaling. Key words: Heat Transfer, Fire II Flight Vehicle, Expansion Tubes, Binary Scaling. NOMENCLATURE dA elemental surface area, m2 H0 stagnation enthalpy, MJ/kg L arbitrary length, m ls scale factor equal to Lf /Le M Mach Number ˙m mass flow rate, kg/s p pressure, kPa ˙q heat transfer rate, W/m2 ¯q averaged heat transfer rate W/m2 RN nose radius m Re Reynolds number, equal to ρURN µ s/RD radial distance from symmetry axis St Stanton number, equal to ˙q ρUH0 St √ Re = ˙qR 1/2 N (ρU)1/2 µ1/2H0 over radius of forebody (D/2) T temperature, K U velocity, m/s Ue equivalent velocity m/s, equal to √ 2H0 U1 primary shock speed m/s U2 secondary shock speed m/s ρ density, kg/m3 ρL binary

  15. Bis{μ-2,2′-[(3-aza­pentane-1,5-di­yl)bis­(nitrilo­methyl­idyne)]diphenolato}dicopper(II) dimethyl sulfoxide disolvate

    PubMed Central

    Quintero-Tellez, Guadalupe; González Álvarez, Carmen María; Bernès, Sylvain; Alcántara-Flores, José Luis; Reyes-Ortega, Yasmi

    2008-01-01

    The title compound, [Cu2(C18H19N3O2)2]·2C2H6OS or [Cu2(SalenN3H)2]·2DMSO, where SalenN3H is the multidentate Schiff base 2,2′-[(3-aza­pentane-1,5-di­yl)bis­(nitrilo­methyl­idyne)]diphenolate dianion and DMSO is dimethyl sulfoxide, is a solvated dinuclear CuII complex. The neutral complex is built from two Cu(SalenN3H) units related by an inversion center. All heteroatoms in the Schiff bases coordinate the CuII ions, which display highly distorted trigonal bipyramidal geometries. The solvent mol­ecules are located in the structural voids of the complex and are disordered over two positions with occupancies of 0.642 (15) and 0.358 (15). The previously characterized acetone disolvate of the same complex presents identical mol­ecular and crystal structures, and crystallizes with cell parameters very close to those of the DMSO disolvate reported here. PMID:21202185

  16. Crystal structure of bis­{μ-4-methyl-N′-[3-(oxido­imino)­butan-2-yl­idene]benzene­sulfono­hydrazidato}bis­[(dimethyl sulfoxide-κO)copper(II)

    PubMed Central

    Siqueira, Diego Pereira; Siqueira, Maria Carolina Bulhosa; Gervini, Vanessa Carratu; Bresolin, Leandro; de Oliveira, Adriano Bof

    2014-01-01

    In the title compound, [Cu2(C11H13N3O3S)2(C2H6OS)2], the CuII cation is N,N′,O-chelated by a deprotonated hy­droxy­imino-tosyl­hydrazone ligand and coordinated by a dimethyl sulfoxide mol­ecule. One O atom from the adjacent hy­droxy­imino-tosyl­hydrazone ligand bridges the CuII cation, forming the centrosymmetric dimeric complex. The cation is in an overall distorted N2O3 square-pyramidal coordination environment. The methyl­benzene ring is twisted with respect to the hydrazine fragment, with a dihedral angle of 89.54 (9)° between the planes. An intra­molecular C—H⋯O hydrogen bond occurs. In the crystal, mol­ecules are linked by weak C—H⋯O and C—H⋯S inter­actions. Weak π–π stacking is also observed between parallel benzene rings of adjacent mol­ecules, the centroid–centroid distance being 3.9592 (17) Å. PMID:25309178

  17. Solar Neutrinos. II. Experimental

    DOE R&D Accomplishments Database

    Davis, Raymond Jr.

    1964-01-01

    A method is described for observing solar neutrinos from the reaction Cl{sup 37}(nu,e{sup -})Ar{sup 37} in C{sub 2}Cl{sub 4}. Two 5 00-gal tanks of C{sub 2}Cl{sub 4} were placed in a limestone mine (1800 m.w.e.) and the resulting Ar{sup 37} activity induced by cosmic mesons( mu ) was measured to determine the necessary conditions for solar neutrino observations. (R.E.U.)

  18. The FERRUM project: Experimental lifetimes and transition probabilities from highly excited even 4d levels in Fe ii

    NASA Astrophysics Data System (ADS)

    Hartman, H.; Nilsson, H.; Engström, L.; Lundberg, H.

    2015-12-01

    We report lifetime measurements of the 6 levels in the 3d6(5D)4d e6G term in Fe ii at an energy of 10.4 eV, and f-values for 14 transitions from the investigated levels. The lifetimes were measured using time-resolved laser-induced fluorescence on ions in a laser-produced plasma. The high excitation energy, and the fact that the levels have the same parity as the the low-lying states directly populated in the plasma, necessitated the use of a two-photon excitation scheme. The probability for this process is greatly enhanced by the presence of the 3d6(5D)4p z6F levels at roughly half the energy difference. The f-values are obtained by combining the experimental lifetimes with branching fractions derived using relative intensities from a hollow cathode discharge lamp recorded with a Fourier transform spectrometer. The data is important for benchmarking atomic calculations of astrophysically important quantities and useful for spectroscopy of hot stars.

  19. Detailed Chemical Kinetic Reaction Mechanism for Biodiesel Components Methyl Stearate and Methyl Oleate

    SciTech Connect

    Naik, C; Westbrook, C K; Herbinet, O; Pitz, W J; Mehl, M

    2010-01-22

    New chemical kinetic reaction mechanisms are developed for two of the five major components of biodiesel fuel, methyl stearate and methyl oleate. The mechanisms are produced using existing reaction classes and rules for reaction rates, with additional reaction classes to describe other reactions unique to methyl ester species. Mechanism capabilities were examined by computing fuel/air autoignition delay times and comparing the results with more conventional hydrocarbon fuels for which experimental results are available. Additional comparisons were carried out with measured results taken from jet-stirred reactor experiments for rapeseed methyl ester fuels. In both sets of computational tests, methyl oleate was found to be slightly less reactive than methyl stearate, and an explanation of this observation is made showing that the double bond in methyl oleate inhibits certain low temperature chain branching reaction pathways important in methyl stearate. The resulting detailed chemical kinetic reaction mechanism includes more approximately 3500 chemical species and more than 17,000 chemical reactions.

  20. Bis{2-meth­oxy-6-[(E)-(4-methyl­benz­yl)imino­meth­yl]phenolato}palladium(II) chloro­form monosolvate

    PubMed Central

    Bahron, Hadariah; Tajuddin, Amalina Mohd; Ibrahim, Wan Nazihah Wan; Chantrapromma, Suchada; Fun, Hoong-Kun

    2014-01-01

    In the title complex, [Pd(C16H16NO2)2]·CHCl3, the PdII cation lies on an inversion center. One Cl atom of the CHCl3 solvent mol­ecule lies on a twofold axis and the C—H group is disordered with equal occupancies about this axis with the other Cl atom in a general position with full occupancy. The PdII cation is four-coordinate and adopts a square-planar geometry via coordination of the imine N and phenolic O atoms of the two bidentate Schiff base anions. The N and O atoms of these ligands are mutually trans. The plane of the benzene ring makes a dihedral angle of 73.52 (10)° with that of the meth­oxy­phenolate ring. In the crystal, mol­ecules of the PdII complex are arranged into sheets parallel to the ac plane, and the chloro­form solvent mol­ecules are located in the inter­stitial areas between the complex mol­ecules. Weak inter­molecular C—H⋯O and C—H⋯π inter­actions stabilize the packing. PMID:25249876

  1. Trypanosome cdc2-related kinase 9 controls spliced leader RNA cap4 methylation and phosphorylation of RNA polymerase II subunit RPB1.

    PubMed

    Badjatia, Nitika; Ambrósio, Daniela L; Lee, Ju Huck; Günzl, Arthur

    2013-05-01

    Conserved from yeast to mammals, phosphorylation of the heptad repeat sequence Tyr(1)-Ser(2)-Pro(3)-Thr(4)-Ser(5)-Pro(6)-Ser(7) in the carboxy-terminal domain (CTD) of the largest RNA polymerase II (RNA Pol II) subunit, RPB1, mediates the enzyme's promoter escape and binding of RNA-processing factors, such as the m(7)G capping enzymes. The first critical step, Ser(5) phosphorylation, is carried out by cyclin-dependent kinase 7 (CDK7), a subunit of the basal transcription factor TFIIH. Many early-diverged protists, such as the lethal human parasite Trypanosoma brucei, however, lack the heptad repeats and, apparently, a CDK7 ortholog. Accordingly, characterization of trypanosome TFIIH did not identify a kinase component. The T. brucei CTD, however, is phosphorylated and essential for transcription. Here we show that silencing the expression of T. brucei cdc2-related kinase 9 (CRK9) leads to a loss of RPB1 phosphorylation. Surprisingly, this event did not impair RNA Pol II transcription or cotranscriptional m(7)G capping. Instead, we observed that CRK9 silencing led to a block of spliced leader (SL) trans splicing, an essential step in trypanosome mRNA maturation, that was caused by hypomethylation of the SL RNA's unique cap4.

  2. Distribution of 1-methyl-4-phneyl-1,2,3,6-tetrahydropyridine in experimental animals studied by positron emission tomography and whole body autoradiography

    SciTech Connect

    Hartvig, P.; Lindquist, N.G.; Aquilonius, S.M.; d'Argy, R.; Bergstroem, K.; Bondesson, U.; Eckernaes, S.A.; Gullberg, P.; Larsson, B.S.; Lindberg, B.

    1986-01-06

    1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is a selective potent neurotoxin which has induced a syndrome similar to parkinsonism both in man and in monkeys. At autopsy degeneration of pigmented nerve cells in the pars compacta of the substantia nigra has been confirmed. The regional distribution of intravenously administered 1-(/sup 11/C-methyl)-4-phenyl-1,2,3,6-tetrahydropyridine (/sup 11/C-MPTP) in the brain of Rhesus monkeys was studied by positron emission tomography and the whole body distribution in mice was documented by autoradiography and by impulse counting of selected tissues. A rapid and high uptake of /sup 11/C-MPTP derived radioactivity was seen in areas corresponding to striatum and midbrain, including the substantia nigra area. Pretreatment of the monkey with spiperone, a selective dopamine receptor antagonist, did not alter uptake nor the kinetics of the /sup 11/C-MPTP derived radioactivity. Thus, /sup 11/C-MPTP does not have a high affinity for postsynaptic dopamine receptors. A remarkably high uptake of /sup 11/C-MPTP derived radioactivity was seen in the eye of the monkey. The selective uptake of radioactivity in the eye was also confirmed in pigmented but not in albino mice. The melanin affinity of MPTP may cause high intracellular concentrations of the compound or its metabolites in the melanin containing nerve cells in substantia nigra, which may explain the serious vulnerability of these neurons to MPTP. 30 references, 3 figures, 2 tables.

  3. Experimental study of the removal of copper ions using hydrogels of xanthan, 2-acrylamido-2-methyl-1-propane sulfonic acid, montmorillonite: Kinetic and equilibrium study.

    PubMed

    Aflaki Jalali, Marzieh; Dadvand Koohi, Ahmad; Sheykhan, Mehdi

    2016-05-20

    In this paper, removal of copper ions from aqueous solution using novel xanthan gum (XG) hydrogel, xanthan gum-graft-2-acrylamido-2-methyl-1-propane sulfonic acid (XG-g-P(AMPS)) hydrogel and xanthan gum-graft-2-acrylamido-2-methyl-1-propane sulfonic acid/montmorillonite (XG-g-P(AMPS)/MMT) hydrogel composite were studied. The structure and morphologies of the xanthan-based hydrogels were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). Adsorbents comprised a porous crosslink structure with side chains that carried carboxyl, hydroxyl and sulfonate. Maximum adsorption was observed in the pH=5.2, initial concentrations of Cu(2+)=321.8 mg/L, Temperature=45 °C, contact time=5 h with 0.2 g/50 mL of the hydrogels. Adsorption process was found to follow Langmuir isotherm model with maximum adsorption capacity of 24.57, 39.06 and 29.49 mg/g for the XG, XG-g-P(AMPS) and XG-g-P(AMPS)/MMT, respectively. Adsorption kinetics data fitted well with pseudo second order model. The negative ΔG° values and the positive ΔS° confirmed that the adsorption was a spontaneous process. The positive ΔH° values suggested that the adsorption was endothermic in nature.

  4. Crystal structure of bis­(1-hexyl-N,N-di­methyl­pyridinium) bis­(maleo­nitrile­dithiol­ato)nickelate(II)

    PubMed Central

    Yu, Shan-Shan; Zhang, Hui

    2016-01-01

    The asymmetric unit of the title compound, (C13H23N2)2[Ni(C4N2S2)2], consists of a 1-hexyl-N,N-di­methyl­pyridinium cation and one half of a [Ni(mnt)2]2− dianion (mnt2− = maleo­nitrile­dithiol­ate) in which the Ni2+ cation lies on a crystallographic inversion centre. The square-planar coordination about Ni2+ comprises four S atoms from two bidentate chelate mnt2− ligands [Ni—S = 2.1791 (9) and 2.1810 (8) Å, and S—Ni—S bite angle = 91.93 (3)°]. The hydro­carbon chains of cations show trans-planar conformations and lie approximately parallel to the long mol­ecular axis of the [Ni(mnt)2]2− anions, giving stacks along the c axis. The anions and cations form layers lying parallel to the bc plane. Only weak C—H⋯Ni and C—H⋯π associations are present in the crystal packing. PMID:27536413

  5. Mutation T318M in the CYP11B2 gene encoding P450c11AS (aldosterone synthase) causes corticosterone methyl oxidase II deficiency

    SciTech Connect

    Zhang, G.; Rodriguez, H.; Miller, W.L.

    1995-11-01

    Corticosterone methyl oxidase (CMO) deficiency refers to disorders of aldosterone synthesis due to mutations in the CYP11B2 gene encoding cytochrome P450c11AS, which is the adrenal aldosterone synthase. Type I CMO deficiency is associated with low concentrations of 18OH-corticosterone and aldosterone, due to severe mutations in P450c11AS, while type III CMO deficiency is associated with high concentrations of 18OH-corticosterone and low concentrations of aldosterone, due to less severe mutations of P450c11AS. A single type of mutation, compound homozygosity for R181W and V386A, has been reported as the cause of CMOII deficiency in an inbred population. We now report a patient with a typical clinical and hormonal picture of CMOII deficiency. Direct sequencing of patient and parent DNAs showed that the mother`s allele contributed R181W and the deletion/frameshift mutation {Delta}C372, while the father`s allele contributed T318M and V386A. These mutants were recreated in cDNA expression vectors singly and in the parental pairs, showing that neither allele contributed any measurable activity. This would suggest the patient should have CMOI deficiency. These studies suggest that other factors besides P450c11AS are involved in the genesis of the distinctive CMOI and CMOII phenotypes. 31 refs., 2 figs., 3 tabs.

  6. Synthesis, characterization, crystal structure and theoretical approach of Cu(II) complex with 4-{(Z)-[(2-hydroxybenzoyl)hydrazono]methyl}benzoic acid

    NASA Astrophysics Data System (ADS)

    Chen, Shi-Liang; Liu, Zheng; Liu, Jie; Han, Guo-Cheng; Li, Yan-Hong

    2012-04-01

    The metal complex of [CuL2]·2DMF (L = 4-{(Z)-[(2-hydroxybenzoyl)hydrazono]methyl}benzoic acid, DMF = N,N-dimethylformamide) (1) had been synthesized and characterized by spectral method(IR), UV-Vis electronic absorption spectra, fluorescence spectra, elemental analysis, electrochemistry, thermal analysis (TG, DTG) and single crystal X-ray diffraction techniques. In the complex, the ligands act as univalent anion bidentate and coordination takes place in the enol tautomeric form with the enolic oxygen and azomethine nitrogen atoms. Molecular geometry from X-ray experiment of the title compound in the ground-state has been compared using the density functional method (B3LYP) and LANL2DZ basis set. DFT calculations at B3LYP/LANL2DZ level of theory prove that the electronic spectra of CuL2·2DMF is attributed to intra-complex electronic transitions as well as π-π* electronic transitions. Also, Mulliken charge analysis, natural bond orbitals (NBO), Wiberg bond index and frontier molecular orbitals (FMO) were performed at B3LYP/LANL2DZ level of theory. In addition, complex 1 exhibits strong photoluminescent emission at room temperature. The electrochemical studies reveal that redox of Cu2+/Cu+ in the complex are quasi-reversible processes. The result of TG analysis shows that the title complex was stable under 100.0 °C.

  7. Experimental and computational studies on 4-[(3,5-dimethyl-1H-pyrazol-1-yl)methoxy]phthalonitrile and synthesis and spectroscopic characterization of its novel phthalocyanine magnesium(II) and tin(II) metal complexes.

    PubMed

    Akçay, Hakkı Türker; Bayrak, Rıza; Sahin, Ertan; Karaoğlu, Kaan; Demirbaş, Umit

    2013-10-01

    The molecular structure of the substituted phthalonitrile was analyzed crystallographically and compared with optimized geometric structure. The structural properties of the compound such as energy, vibrational frequency, ground state transitions, (1)H and (13)C NMR chemical shifts, NBO analysis and hyperpolarizability were computed by DFT (Density Functional Theory) method and compared with experimental results. The novel Mg(II) and Sn(II) phthalocyanines synthesized from the substituted phthalonitrile and their aggregation behaviors were investigated in different solvents and at different concentrations in DMSO.

  8. Employment of methyl 2-pyridyl ketone oxime in 3d/4f-metal chemistry: dinuclear nickel(II)/lanthanide(III) species and complexes containing the metals in separate ions.

    PubMed

    Polyzou, Christina D; Nikolaou, Helen; Papatriantafyllopoulou, Constantina; Psycharis, Vassilis; Terzis, Aris; Raptopoulou, Catherine P; Escuer, Albert; Perlepes, Spyros P

    2012-11-28

    The use of methyl 2-pyridyl ketone oxime (mpkoH) for the synthesis of Ni(II)/Ln(III) (Ln = lanthanide) complexes, using "one-pot" reactions in the absence of an external base, is described. Depending on the reaction and crystallization conditions employed, two families of complexes have been obtained. The first family consists of true heterometallic species and involves complexes [NiLn(mpko)(3)(mpkoH)(3)](ClO(4))(2), where Ln = Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho and Er. The second family contains the pseudo heterometallic complexes [Ni(mpkoH)(3)](2)[Ln(NO(3))(6)](ClO(4)), where Ln = La, Ce, Pr, Nd and Sm. The crystal structures of [NiCe(mpko)(3)(mpkoH)(3)](ClO(4))(2) (1), [NiDy(mpko)(3)(mpkoH)(3)](ClO(4))(2) (8) and [Ni(mpkoH)(3)](2)[La(NO(3))(6)](ClO(4)) (11) have been determined by single-crystal, X-ray crystallography. Complexes 1·1.2MeOH·0.6H(2)O and 8·1.2MeOH·0.6H(2)O crystallise in the monoclinic space group P2(1)/a and are isomorphous; there are two crystallographically independent cations in the unit cell, but their interatomic distances and angles differ little. The Ni(II) and Ln(III) ions are bridged by three oximate groups belonging to the η(1):η(1):η(1):μ mpko(-) ligands. The Ni(II) centre is octahedrally coordinated by the six nitrogen atoms of the mpko(-) ligands in a facial arrangement. The Ln(III) centre is bound to an (O(oximate))(3)N(6) set of donor atoms, the nitrogen atoms belonging to the three N,N'-bidentate chelating mpkoH ligands. The stereochemistry of the Ln(III) atoms has been evaluated by means of continuous shape measures (CShM). The two crystallographically independent Ce(III) atoms in 1 have tricapped trigonal prismatic and capped square antiprismatic coordination geometries, while the polyhedra of the Dy(III) atoms in 8 are both close to a tricapped trigonal prism. The octahedral Ni(II) atoms in 11 are both facially bound to a N(6) set of donor atoms from three N,N'-bidentate chelating mpkoH ligands, while the 12-coordinate

  9. Di-aqua-bis-(2-ethyl-5-methyl-imidazole-4-sulfonato-κ(2) N (3),O)nickel(II) dihydrate.

    PubMed

    Purdy, Andrew P; Butcher, Ray J

    2014-01-01

    In the title complex, [Ni(C6H9N2O3S)2(H2O)2]·2H2O, the Ni(II) atom lies on an inversion center and is chelated by N and O atoms of two symmetry-equivalent imidazole-sulfonate ligands in the basal plane, and two water O atoms in axial positions in an overall octa-hedral configuration. The crystal structure displays O-H⋯O and N-H⋯O hydrogen bonds, which connect the components into an extended three-dimensional network. PMID:24526946

  10. Synthesis, crystal structures and intermolecular interactions of two Mn(II) complexes with 4,4‧-bipy and methyl benzoates

    NASA Astrophysics Data System (ADS)

    Xin-Jian, Wu; Yi-Ping, Chen; Ze-Min, Xia; Su-Zhi, Ge; Feng, Chai; Ling-Yan, Zhao; Jian-Zhong, Chen

    2013-03-01

    Two manganese complexes containing 4,4'-bipyridine and methyl benzoate as ligands have been prepared and crystallized by solvent evaporation method in DMF. The single crystal X-ray crystallographic analyses reveal that the complexes crystallize in monoclinic system. Crystal of 1 [Mn2(4,4'-bipy)2 (o-MBA)4]n has space group of P21/c with unit cell parameters of a = 17.508 (Å), b = 11.6229 (Å), c = 27.983 (Å), β = 128.123°, V = 4.4797 nm3, empirical formula: C52H44Mn2N4O8, Mr = 962.79, Z = 4, Dc = 1.428 g/cm3, μ = 0.625 mm-1, and F(000) = 1992. The crystal of 2 [Mn (4,4'-bipy)(m-MBA)2]n belongs to space group C2/c with a = 16.079 (Å), b = 11.652 (Å), c = 24.887 (Å), β = 92.02°, V = 4.660 nm3, empirical formula: C26H22MnN2O4, Mr = 481.40, Z = 8, Dc = 1.372 g/cm3, μ = 1.179 mm-1, F(000) = 1992. The weak interactions in structures are observed from the X-ray crystallographic data. These include the Csbnd H⋯O hydrogen bonds, π-π stacking and Csbnd H⋯π interactions found in 1. The different strength of intermolecular interaction in the structures is reflected on their different thermal stability of the two complexes measured by thermal gravimetric analysis and the 2D-IR correlation spectroscopy. The study of weak interactions is meaningful to provide supporting data for potential application in molecular biology.

  11. The vegetarian lifestyle and DNA methylation.

    PubMed

    Geisel, Jürgen; Schorr, Heike; Bodis, Marion; Isber, Sonia; Hübner, Ulrich; Knapp, Jean-Pierre; Obeid, Rima; Herrmann, Wolfgang

    2005-01-01

    Vegetarians have a lower intake of vitamin B12 than omnivores do. Vitamin B12 deficiency (holotranscobalamin II <35 pmol/L or methylmalonic acid >271 nmol/L) was found in 58% of 71 vegetarians studied. Higher homocysteine levels (>12 micromol/L) found in 45% indicate disturbed remethylation of homocysteine to methionine. The methylation of DNA is strongly linked to homocysteine metabolism. Since DNA methylation is an important epigenetic factor in the regulation of gene expression, alteration of the methylation pattern has been associated with aging, cancer, atherosclerosis and other diseases. Three observations indicate that DNA methylation could be diminished by a vegetarian lifestyle. The vegetarian diet has a low content of methionine, remethylation of homocysteine is reduced by vitamin B12 deficiency and elevated homocysteine levels can induce the generation of S-adenosylhomocysteine (SAH), a potent inhibitor of methyltransferases. In our study we observed a significant correlation between SAH and whole-genome methylation (r=-0.36, p<0.01). This observation underlines the role of SAH as a potent inhibitor of methyltransferases. The methylation status was not correlated with homocysteine or S-adenosylemethionine (SAM). These results indicate that the degree of methylation does not depend on the supply of methyl groups and that the reverse generation of SAH has no influence. In addition to whole-genome methylation, the specific promoter methylation of the p66Shc gene was studied. However, the latter did not correlate with SAH, SAM or homocysteine. Obviously, the promoter methylation of the p66Shc gene is controlled in a specific way, without following the general regulating influence of SAH. In conclusion, an inhibitory effect of SAH on whole-genome methylation was found, but from our data no interaction between vegetarian lifestyle and DNA methylation could be determined.

  12. Crystal structure of μ-1κC:2(η2)-carbonyl-carbonyl-1κC-chlorido-2κCl-μ-chlorido­borylene-1:2κ2 B:B-[1(η5)-penta­methyl­cyclo­penta­dien­yl](tri­cyclo­hexyl­phosphane-2κP)iron(II)platinum(II) benzene monosolvate

    PubMed Central

    Braunschweig, Holger; Kramer, Thomas

    2014-01-01

    In the mol­ecular structure of the dinuclear title compound [η5-(C5(CH3)5)(CO)Fe{(μ-BCl)(μ-CO)}PtCl(P(C6H11)3)]·C6H6, the two metal atoms, iron(II) and platinum(II), are bridged by one carbonyl (μ-CO) and one chlorido­borylene ligand (μ-BCl). The PtII atom is additionally bound to a chloride ligand situated trans to the bridging borylene, and a tri­cyclo­hexyl­phosphane ligand (PCy3) trans to the carbonyl ligand, forming a distorted square-planar structural motif at the PtII atom. The FeII atom is bound to a penta­methyl­cyclo­penta­dienyl ligand [η5-C5(CH3)5] and one carbonyl ligand (CO), forming a piano-stool structure. Additionally, one benzene solvent mol­ecule is incorporated into the crystal structure, positioned staggered relative to the penta­methyl­cyclo­penta­dienyl ligand at the FeII atom, with a centroid–centroid separation of 3.630 (2) Å. PMID:25484763

  13. Experimental validation of improved 3D SBP positioning algorithm in PET applications using UW Phase II Board

    NASA Astrophysics Data System (ADS)

    Jorge, L. S.; Bonifacio, D. A. B.; DeWitt, Don; Miyaoka, R. S.

    2016-12-01

    Continuous scintillator-based detectors have been considered as a competitive and cheaper approach than highly pixelated discrete crystal positron emission tomography (PET) detectors, despite the need for algorithms to estimate 3D gamma interaction position. In this work, we report on the implementation of a positioning algorithm to estimate the 3D interaction position in a continuous crystal PET detector using a Field Programmable Gate Array (FPGA). The evaluated method is the Statistics-Based Processing (SBP) technique that requires light response function and event position characterization. An algorithm has been implemented using the Verilog language and evaluated using a data acquisition board that contains an Altera Stratix III FPGA. The 3D SBP algorithm was previously successfully implemented on a Stratix II FPGA using simulated data and a different module design. In this work, improvements were made to the FPGA coding of the 3D positioning algorithm, reducing the total memory usage to around 34%. Further the algorithm was evaluated using experimental data from a continuous miniature crystal element (cMiCE) detector module. Using our new implementation, average FWHM (Full Width at Half Maximum) for the whole block is 1.71±1 mm, 1.70±1 mm and 1.632±5 mm for x, y and z directions, respectively. Using a pipelined architecture, the FPGA is able to process 245,000 events per second for interactions inside of the central area of the detector that represents 64% of the total block area. The weighted average of the event rate by regional area (corner, border and central regions) is about 198,000 events per second. This event rate is greater than the maximum expected coincidence rate for any given detector module in future PET systems using the cMiCE detector design.

  14. A new three-dimensional zinc(II) coordination polymer involving 2-[(1H-1,2,4-triazol-1-yl)methyl]-1H-benzimidazole and benzene-1,4-dicarboxylate ligands.

    PubMed

    Jian, Shou Jun; Han, Qian Qian; Yang, Huai Xia; Meng, Xiang Ru

    2016-07-01

    Metal-organic frameworks (MOFs) based on multidentate N-heterocyclic ligands involving imidazole, triazole, tetrazole, benzimidazole, benzotriazole or pyridine present intriguing molecular topologies and have potential applications in ion exchange, magnetism, gas sorption and storage, catalysis, optics and biomedicine. The 2-[(1H-1,2,4-triazol-1-yl)methyl]-1H-benzimidazole (tmb) ligand has four potential N-atom donors and can act in monodentate, chelating, bridging and tridentate coordination modes in the construction of complexes, and can also act as both a hydrogen-bond donor and acceptor. In addition, the tmb ligand can adopt different coordination conformations, resulting in complexes with helical structures due to the presence of the flexible methylene spacer. A new three-dimensional coordination polymer, poly[[bis(μ2-benzene-1,4-dicarboxylato)-κ(4)O(1),O(1'):O(4),O(4');κ(2)O(1):O(4)-bis{μ2-2-[(1H-1,2,4-triazol-1-yl)methyl-κN(4)]-1H-benzimidazole-κN(3)}dizinc(II)] trihydrate], {[Zn(C8H4O4)(C10H9N5)]·1.5H2O}n, has been synthesized by the reaction of ZnCl2 with tmb and benzene-1,4-dicarboxylic acid (H2bdic) under solvothermal conditions. There are two crystallographically distinct bdic(2-) ligands [bdic(2-)(A) and bdic(2-)(B)] in the structure which adopt different coordination modes. The Zn(II) ions are bridged by tmb ligands, leading to one-dimensional helical chains with different handedness, and adjacent helices are linked by bdic(2-)(A) ligands, forming a two-dimensional network structure. The two-dimensional layers are further connected by bdic(2-)(B) ligands, resulting in a three-dimensional framework with the topological notation 6(6). The IR spectra and thermogravimetric curves are consistent with the results of the X-ray crystal structure analysis and the title polymer exhibits good fluorescence in the solid state at room temperature. PMID:27377273

  15. Inclusion compounds between α-, β- and γ-cyclodextrins: iron II lactate: a theoretical and experimental study using diffusion coefficients and molecular mechanics

    NASA Astrophysics Data System (ADS)

    Leite, Rosiley A.; Lino, Antonio C. S.; Takahata, Yuji

    2003-01-01

    The inclusion compounds between iron II lactate and three different cyclodextrins (CDs) were studied by means of experimental and theoretical data. The importance of iron II in the human metabolism effort the necessity of a minimum concentration to the human life. Malnutrition is one great problem in social politics of many countries on the world. The possibility to the development of novel medicines with the iron II species stable look for an increase on the efficiency for this kind of aid. Kinetics measurements confirm the possibility to stop the oxidation reaction. It was the first indication of efficient molecular encapsulation. Diffusion coefficient measurements were carried out by Taylor-Aris diffusion technique. The decrease of diffusion coefficients measured for iron II lactate when alone and forming the inclusion complexes was obtained for all hosts molecules used. Molecular Mechanics calculations were performed to elucidate the perfect arrange of iron II lactate inside CDs cavity. No great differences were obtained to the binding energy for the different hosts. Using the software HyperChem6.03v MM+, AMBER94 and OPLS Forced Fields for iron atom in two chemical environments (a) vacuum and (b) with addition of 250 water molecules (MM+). The solvent treatment was decisive to the order of stability. This order was β-CD>γ-CD>α-CD, the same order of solubility in water. The results contained in this work confirm the possibility to protect iron II lactate against oxidation.

  16. Sarcolemmal phospholipid N-methylation in genetically determined hamster cardiomyopathy

    SciTech Connect

    Okumura, K.; Panagia, V.; Jasmin, G.; Dhalla, N.S.

    1987-02-27

    The heart sarcolemmal phosphatidylethanolamine N-methylation in UM-X7.1 strain of cardiomyopathic hamsters was examined by using 0.055, 10 and 150 microM S-adenosyl-L-(methyl-/sup 3/H) methionine as methyl donor for sites I, II and III, respectively. In comparison with control values, methylation activities at site I was increased in 40, 120 and 250 days old cardiomyopathic hamsters. On the other hand, methylation activities at sites II and III in 120 and 250 days old cardiomyopathic animals were depressed without any change in the 40 days old group. The alterations in N-methylation activities were associated with kinetic changes in apparent Vmax values without any changes in the apparent Km. These results indicate a defect in the phospholipid N-methylation process in heart sarcolemma during the development of genetically determined cardiomyopathy.

  17. Crystal structure of a tetranuclear Cu(II) complex with an O,N,N'-donor Schiff base ligand: hexa-μ2-acetato-bis-(2-{[(2,2,6,6-tetra-methyl-piperidin-4-yl)imino]-meth-yl}phenolato-κ(3) O,N,N')tetra-copper(II).

    PubMed

    Huang, Guohui; Liu, Xiaoxuan

    2016-04-01

    The title compound, [Cu4(CH3COO)6(C16H23N2O)2], lies across a twofold rotation axis. The asymmetric unit contains two independent Cu(II) ions. The symmetry-unique terminal Cu(II) ion is O,N,N'-coordinated by a 2-{[(2,2,6,6-tetra-methyl-piperidin-4-yl)imino]-meth-yl}phenolate ligand and an O atom from an acetate group in a slightly distorted square-planar coordination environment. The symmetry-unique central Cu(II) ion is coordinated by a different O atom from the same acetate group and by four bridging acetate ligands, which connect the asymmetric unit into a dimeric complex and form a distorted square-pyramidal coordination environment. Within the complex there are two symmetry-equivalent intra-molecular N-H⋯O hydrogen bonds. In the crystal, weak C-H⋯O hydrogen bonds link the complex mol-ecules, forming a three-dimensional network. PMID:27375896

  18. Using an experimental medicine model to understand the antidepressant potential of the N-Methyl-D-aspartic acid (NMDA) receptor antagonist memantine.

    PubMed

    Pringle, A; Parsons, E; Cowen, L G; McTavish, S F; Cowen, P J; Harmer, C J

    2012-11-01

    There is growing interest in the role of the glutamatergic system both in depression and as a novel target for treatments. Preclinical studies suggested that the non-competitive N-Methyl-D-aspartic acid (NMDA) receptor antagonist memantine might have antidepressant properties, but a randomised controlled trial failed to support this. A healthy volunteer model of emotional processing was used to assess the neuropsychological profile of action of memantine. Healthy volunteers (n=32) were randomised to receive a single dose of memantine (10 mg) or placebo, and subsequently completed a battery of tasks measuring emotional processing, including facial expression recognition, emotional memory, dot-probe and emotion-potentiated startle tasks, as well as working and verbal memory. Memantine treated volunteers showed an increased emotion-potentiated startle, and a reduced bias for negative items in emotional recognition memory. There were no effects of the drug on any other aspect of emotional or non-emotional information processing. These results suggest that a single dose of memantine produces an early anxiogenic response in the emotion-potentiated startle similar to that seen following a single dose of the selective serotonin reuptake inhibitor, citalopram. However, the overall profile of effects is more limited than that which might be expected in response to a conventional antidepressant.

  19. Inhibition of indoleamine 2,3-dioxygenase by stereoisomers of 1-methyl tryptophan in an experimental graft-versus-tumor model.

    PubMed

    Lim, Ji-Young; Lee, Sung-Eun; Park, Gyenogsin; Choi, Eun Young; Min, Chang-Ki

    2014-10-01

    Indoleamine 2,3-dioxygenase (IDO) is a rate-limiting enzyme in tryptophan catabolism that plays an important role in the induction of immune tolerance. Its role in graft-versus-tumor effect after allogeneic stem cell transplantation (allo-SCT) remains unclear. Using a murine graft-versus-tumor model of reduced-intensity allo-HSCT followed by donor leukocyte infusion (DLI), we examined the role of IDO inhibition. Two stereoisomers of 1-methyl tryptophan (1-MT), a small-molecule inhibitor of IDO, reduced the growth of inoculated tumor in the mice that received DLI and had higher expression of IDO1 and IFNγ. However, L-1MT, but not D-1MT, mitigated tumor growth in mice that did not receive DLI and did not express IDO1 and IFNγ. Accordingly, both stereoisomers reduced plasma kynurenine concentrations early after DLI and enhanced in vitro cytotoxic lymphocyte function after allogeneic mixed lymphocyte reaction. Furthermore, L-1MT was more efficient in causing direct cytotoxic effects than D-1MT. Our results suggest that IDO inhibition can benefit anti-tumor therapy in the setting of reduced-intensity allo-SCT using DLI. PMID:24971697

  20. Study the Effect of S-Methyl L-Cysteine on Lipid Metabolism in an Experimental Model of Diet Induced Obesity

    PubMed Central

    G.P., Senthilkumar; Thomas, Sithara; K., Sivaraman; Sankar, P.; Bobby, Zachariah

    2013-01-01

    Background: S-methyl L-cysteine (SMC) is a hydrophilic cysteine-containing compound naturally found in Alium plants such as, garlic and onion. Objectives: The present study was aimed to evaluate the hypoglycemic and antihyperlipidemic properties of SMC in high fructose induced diabetic rats. Material and Methods: The present study was designed to evaluate the hypoglycemic and antihyperlipidemic properties of SMC in high fructose induced diabetic rats. Blood samples were collected and the fasting plasma glucose, lipid profile, total antioxidant status (TAS) aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were estimated using standard procedures. Differences between the groups were assessed by using One way Analysis of Variance with (ANOVA) Tukey post hoc test. Results: Oral administration of SMC at a dose of 100 mg/kg bodyweight/day to HFD-treated rats for a period of 60 days showed significant reduction in the animal weight, fasting plasma glucose, total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), VLDL-C and elevation in the level of high-density lipoprotein cholesterol (HDL-C) and TAS compared with fructose fed group. The effects of SMC was compared with metformin; a well-known antihyperglycemic drug. Conclusion: In conclusion, SMC found to be effective in improving the high fructose induced hyperglycemia and dyslipidemia. It may possibly provide a potential adjuvant for the treatment and management of diabetes. PMID:24392369

  1. Crystal structure of di­aqua­bis­(N,N-di­ethyl­nicotinamide-κN 1)bis­(2,4,6-tri­methyl­benzoato-κO 1)cobalt(II)

    PubMed Central

    Aşkın, Gülçin Şefiye; Necefoğlu, Hacali; Özkaya, Safiye; Çatak Çelik, Raziye; Hökelek, Tuncer

    2016-01-01

    The centrosymmetric mol­ecule in the monomeric title cobalt complex, [Co(C10H11O2)2(C10H14N2O)2(H2O)2], contains two water mol­ecules, two 2,4,6-tri­methyl­benzoate (TMB) ligands and two di­ethyl­nicotinamide (DENA) ligands. All ligands coordinate to the CoII atom in a monodentate fashion. The four O atoms around the CoII atom form a slightly distorted square-planar arrangement, with the distorted octa­hedral coordination sphere completed by two pyridine N atoms of the DENA ligands. The dihedral angle between the planar carboxyl­ate group and the adjacent benzene ring is 84.2 (4)°, while the benzene and pyridine rings are oriented at a dihedral angle of 38.87 (10)°. The water mol­ecules exhibit both intra­molecular (to the non-coordinating carboxyl­ate O atom) and inter­molecular (to the amide carbonyl O atom) O—H⋯O hydrogen bonds. The latter lead to the formation of layers parallel to (100), enclosing R 4 4(32) ring motifs. These layers are further linked via weak C—H⋯O hydrogen bonds, resulting in a three-dimensional network. One of the two ethyl groups of the DENA ligand is disordered over two sets of sites with an occupancy ratio of 0.490 (13):0.510 (13). PMID:27375874

  2. Crystal structure of di-aqua-bis-(N,N-di-ethyl-nicotinamide-κN (1))bis-(2,4,6-tri-methyl-benzoato-κO (1))cobalt(II).

    PubMed

    Aşkın, Gülçin Şefiye; Necefoğlu, Hacali; Özkaya, Safiye; Çatak Çelik, Raziye; Hökelek, Tuncer

    2016-04-01

    The centrosymmetric mol-ecule in the monomeric title cobalt complex, [Co(C10H11O2)2(C10H14N2O)2(H2O)2], contains two water mol-ecules, two 2,4,6-tri-methyl-benzoate (TMB) ligands and two di-ethyl-nicotinamide (DENA) ligands. All ligands coordinate to the Co(II) atom in a monodentate fashion. The four O atoms around the Co(II) atom form a slightly distorted square-planar arrangement, with the distorted octa-hedral coordination sphere completed by two pyridine N atoms of the DENA ligands. The dihedral angle between the planar carboxyl-ate group and the adjacent benzene ring is 84.2 (4)°, while the benzene and pyridine rings are oriented at a dihedral angle of 38.87 (10)°. The water mol-ecules exhibit both intra-molecular (to the non-coordinating carboxyl-ate O atom) and inter-molecular (to the amide carbonyl O atom) O-H⋯O hydrogen bonds. The latter lead to the formation of layers parallel to (100), enclosing R 4 (4)(32) ring motifs. These layers are further linked via weak C-H⋯O hydrogen bonds, resulting in a three-dimensional network. One of the two ethyl groups of the DENA ligand is disordered over two sets of sites with an occupancy ratio of 0.490 (13):0.510 (13). PMID:27375874

  3. A combined experimental and theoretical investigation of a new imineoxime and its palladium(II) and platinum(II) complexes: Synthesis, structural characterization and spectroscopic properties

    NASA Astrophysics Data System (ADS)

    Kaya, Yunus; Icsel, Ceyda; Yilmaz, Veysel T.; Buyukgungor, Orhan

    2014-12-01

    A new imineoxime compound {(1E,2E)-(2-hydroxy-ethylimino)-naphthalene-2yl-ethanal oxime (heineoH)} and its palladium(II) and platinum(II) complexes ([M(heineo)2]) have been synthesized and characterized by IR, NMR, UV-vis, elemental analysis, mass spectra and X-ray single crystal diffraction. [Pt(heineo)2] was obtained as a single crystal, while [Pd(heineo)2] was synthesized as a polycrystalline powder. The X-ray diffraction analysis of the [Pt(heineo)2] indicated that the platinum(II) ion is coordinated by two heineo ligands in a distorted square-planar geometry. DFT (B3LYP/6-311++G(d,p) and LANL2DZ) calculations on the ligand and its complexes were carried out to correlate the geometry and vibrational and electronic properties. Additionally, heineoH is fluorescent in EtOH at room temperature, but the fluorescence is quenched in the case of the metal complexes.

  4. A combined experimental and theoretical investigation of a new imineoxime and its palladium(II) and platinum(II) complexes: synthesis, structural characterization and spectroscopic properties.

    PubMed

    Kaya, Yunus; Icsel, Ceyda; Yilmaz, Veysel T; Buyukgungor, Orhan

    2014-12-10

    A new imineoxime compound {(1E,2E)-(2-hydroxy-ethylimino)-naphthalene-2yl-ethanal oxime (heineoH)} and its palladium(II) and platinum(II) complexes ([M(heineo)2]) have been synthesized and characterized by IR, NMR, UV-vis, elemental analysis, mass spectra and X-ray single crystal diffraction. [Pt(heineo)2] was obtained as a single crystal, while [Pd(heineo)2] was synthesized as a polycrystalline powder. The X-ray diffraction analysis of the [Pt(heineo)2] indicated that the platinum(II) ion is coordinated by two heineo ligands in a distorted square-planar geometry. DFT (B3LYP/6-311++G(d,p) and LANL2DZ) calculations on the ligand and its complexes were carried out to correlate the geometry and vibrational and electronic properties. Additionally, heineoH is fluorescent in EtOH at room temperature, but the fluorescence is quenched in the case of the metal complexes. PMID:24929321

  5. A synthetic peptide from the third hypervariable region of major histocompatibility complex class II beta chain as a vaccine for treatment of experimental autoimmune encephalomyelitis.

    PubMed Central

    Topham, D J; Nag, B; Arimilli, S; Sriram, S

    1994-01-01

    Experimental autoimmune encephalomyelitis (EAE) is a class II major histocompatibility complex (MHC)-restricted, T-cell-mediated, demyelinating autoimmune disease of the central nervous system and represents a model for human multiple sclerosis. The present study demonstrates that vaccination of SJL/J mice with an 18-amino acid synthetic peptide from the third hypervariable region of the murine class II MHC IAs beta chain (IAs beta 58-75; 18-mer peptide) is capable of eliciting auto-anti-IAs antibodies specific for the IAs beta chain and preventing and treating EAE. A similar approach may be useful in the treatment of human autoimmune diseases in which susceptibility is linked to class II MHC genes. Images PMID:8058747

  6. catena-Poly[[[diaqua-bis(2-methyl-6-oxo-1,6-dihydro-3,4'-bipyridine-5-carbo-nitrile)copper(II)]-μ-sulfato] tetra-hydrate].

    PubMed

    Niu, Cao-Yuan; Ning, Ai-Min; Feng, Chao-Ling; Dang, Yu-Li; Kou, Chun-Hong

    2008-01-01

    In the title polymer, {[Cu(SO(4))(C(12)H(9)N(3)O)(2)(H(2)O)(2)]·4H(2)O}(n), both the metal center and the sulfate anion are located on a twofold axis. The Cu(II) ion is coordinated by two pyridyl N atoms from two symmetry-related organic ligands, two O atoms from two symmetry-related water mol-ecules, and two O atoms from two symmetry-related sulfate anions, resulting in a distorted octa-hedral geometry. The sulfate anions act as μ(2)-bridges and connect metal ions, forming a one-dimensional chain along the b axis. The three-dimensional crystal structure is established through inter-molecular N-H⋯O and O-H⋯O hydrogen bonds involving the organic ligands, sulfate anions, coordinated and uncoordinated water mol-ecules, and through π-π inter-acting 2-pyridone rings, with centroid-centroid separations of ca 3.96 Å and tilt angles of ca 2.62°. PMID:21581209

  7. Synthesis and structural characterization of molybdenum(VI) and iron(II) coordination compounds with S-alkyl-N-methyl-S-(2-pyridyl)sulfoximines and catalytic epoxidation activity of the molybdenum complexes.

    PubMed

    Brussaard, Yvonne; Olbrich, Falk; Schaumann, Ernst

    2013-11-18

    Coordination compounds oxido(diperoxido)(S-butyl-N-methyl-S-(2-pyridyl)sulfoximine)molybdenum(VI), [MoO(O2)2{SO(NMe)(n)Bu(NC5H4)}] (5c), and bis{(dichlorido)(N,S-dimethyl-2-pyridylsulfoximine)iron(II)}, tetrahydrofuran solvate (1:1) (6), [FeCl2{SO(NMe)Me(NC5H4)}]2·THF are prepared from the free ligand 4 and molybdenum(VI) oxidediperoxide(dihydrate) and iron dichloride, respectively. The crystal structures reveal a trigonal bipyramid with the pyridine ring and the single oxygen on molybdenum in a trans arrangement for 5c and a planar μ(2)-Cl2Fe2 ring with trans-oriented exocyclic Cl atoms for 6 whereas the structures of the N,N-dicoordinated ligands are only little effected by the metals. Coordination compounds (5) efficiently catalyze the epoxidation of cyclooctene or of monosubstituted alkenes by tert-butyl hydroperoxide.

  8. (2-Amino-7-methyl-4-oxidopteridine-6-carboxyl­ato-κ3 O 4,N 5,O 6)aqua­(ethane-1,2-diamine-κ2 N,N′)nickel(II) dihydrate

    PubMed Central

    Baisya, Siddhartha S.; Roy, Parag S.

    2013-01-01

    The NiII atom in the title complex, [Ni(C8H5N5O3)(C2H8N2)(H2O)]·2H2O, is six-coordinated in a distorted octa­hedral geometry by a tridentate 2-amino-7-methyl-4-oxidopteridine-6-carboxyl­ate (pterin) ligand, a bidentate ancillary ethane-1,2-diamine (en) ligand and a water mol­ecule. The pterin ligand forms two chelate rings. The en and pterin ligands are arranged nearly orthogonally [dihedral angle between the mean plane of the en mol­ecule and the pterin ring = 77.1 (1)°]. N—H⋯O, O—H⋯N and O—H⋯O hydrogen bonds link the complex mol­ecules and lattice water mol­ecules into a three-dimensional network. π–π inter­actions are observed between the pyrazine and pyrimidine rings [centroid–centroid distance = 3.437 (2) Å]. PMID:23424441

  9. Cu(II)-mediated atom transfer radical polymerization of methyl methacrylate via a strategy of thermo-regulated phase-separable catalysis in a liquid/liquid biphasic system: homogeneous catalysis, facile heterogeneous separation, and recycling.

    PubMed

    Pan, Jinlong; Zhang, Bingjie; Jiang, Xiaowu; Zhang, Lifen; Cheng, Zhenping; Zhu, Xiulin

    2014-09-01

    A strategy of thermo-regulated phase-separable catalysis (TPSC) is applied to the Cu(II)-mediated atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) in a p-xylene/PEG-200 biphasic system. Initiators for continuous activator regeneration ATRP (ICAR ATRP) are used to establish the TPSC-based ICAR ATRP system using water-soluble TPMA as a ligand, EBPA as an initiator, CuBr2 as a catalyst, and AIBN as a reducing agent. By heating to 70 °C, unlimited miscibility of both solvents is achieved and the polymerization can be carried out under homogeneous conditions; then on cooling to 25 °C, the mixture separates into two phases again. As a result, the catalyst complex remains in the PEG-200 phase while the obtained polymers stay in the p-xylene phase. The catalyst can therefore be removed from the resultant polymers by easily separating the two different layers and can be reused again. It is important that well-defined PMMA with a controlled molecular weight and narrow molecular weight distribution could be obtained using this TPSC-based ICAR ATRP system.

  10. Aqua-{2-(pyridin-2-yl)-N-[(pyridin-2-yl)methyl-idene]ethanamine-κ(3) N,N',N''}(sulfato-κ(2) O,O')copper(II) tetra-hydrate.

    PubMed

    Tinguiano, Daniel; Sow, Mouhamadou Moustapha; Tamboura, Farba Bouyagui; Barry, Aliou Hamady; Gaye, Mohamed

    2013-01-01

    The title complex, [Cu(SO4)(C13H13N3)(H2O)]·4H2O, was obtained by mixing copper sulfate penta-hydrate and 2-(pyridin-2-yl)-N-(pyridin-2-yl-methyl-idene)ethanamine in eth-anol under reflux conditions. The Cu(II) ion shows a Jahn-Teller-distorted octa-hedral geometry, with equatorial positions occupied by three N atoms from the tridentate ligand (average Cu-N = 2.004 Å) and one O atom from a bidentate sulfate anion [Cu-O = 1.963 (2) Å]. The axial positions are occupied by one O atom from a coordinating water mol-ecule [Cu-O = 2.230 (3) Å] and one weakly bonded O atom [Cu-O = 2.750 (2) Å] from the bidentate sulfate ion. The complex mol-ecules are connected through O-H⋯O hydrogen bonds between the coordinating water mol-ecules and sulfate ions from neighboring complexes, forming a double chain parallel to the c axis. The chains are stabilized through additional hydrogen bonds by one of the non-coordinating water mol-ecules bridging between neighboring strands of the double chains. The remaining three water mol-ecules fill the inter-stitial space between the double chains and are involved in an intricate hydrogen-bonding network that consolidates the structure. PMID:23476324

  11. Cu(II)-mediated atom transfer radical polymerization of methyl methacrylate via a strategy of thermo-regulated phase-separable catalysis in a liquid/liquid biphasic system: homogeneous catalysis, facile heterogeneous separation, and recycling.

    PubMed

    Pan, Jinlong; Zhang, Bingjie; Jiang, Xiaowu; Zhang, Lifen; Cheng, Zhenping; Zhu, Xiulin

    2014-09-01

    A strategy of thermo-regulated phase-separable catalysis (TPSC) is applied to the Cu(II)-mediated atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) in a p-xylene/PEG-200 biphasic system. Initiators for continuous activator regeneration ATRP (ICAR ATRP) are used to establish the TPSC-based ICAR ATRP system using water-soluble TPMA as a ligand, EBPA as an initiator, CuBr2 as a catalyst, and AIBN as a reducing agent. By heating to 70 °C, unlimited miscibility of both solvents is achieved and the polymerization can be carried out under homogeneous conditions; then on cooling to 25 °C, the mixture separates into two phases again. As a result, the catalyst complex remains in the PEG-200 phase while the obtained polymers stay in the p-xylene phase. The catalyst can therefore be removed from the resultant polymers by easily separating the two different layers and can be reused again. It is important that well-defined PMMA with a controlled molecular weight and narrow molecular weight distribution could be obtained using this TPSC-based ICAR ATRP system. PMID:25155655

  12. Synthesis, spectroscopic, crystal structure and DNA binding of Ru(II) complexes with 2-hydroxy-benzoic acid [1-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-ethylidene]-hydrazide

    NASA Astrophysics Data System (ADS)

    Chitrapriya, Nataraj; Sathiya Kamatchi, Thangavel; Zeller, Matthias; Lee, Hyosun; Natarajan, Karuppannan

    2011-10-01

    Reactions of 2-hydroxy-benzoic acid [1-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-ethylidene]-hydrazide (H 2L) with [RuHCl(CO)(EPh 3) 3] (E = P or As) were carried out and the new complexes obtained were characterized by elemental analysis, electronic, IR, 1H NMR and 13C NMR spectroscopic techniques and single crystal X-ray diffraction studies. Complex ( 1) crystallizes in the monoclinic space group P2(1)/ c with unit cell dimensions a = 18.6236(17) Å, b = 12.8627(12) Å, c = 21.683(2) Å, α = 90.00, β = 114.626(2), γ = 90.00 V = 4721.8(8) Å, Z = 4. The crystal structure of the complex shows Ru(II) atom is six-coordinated, forming a slightly distorted octahedral geometry with two P atoms in axial positions, and three chelating donor atoms of the tridentate Schiff base ligand and one carbonyl group located in the equatorial plane. The molecular structure is stabilized by intramolecular O—H···N interactions. No intermolecular hydrogen bond was observed. The intramolecular hydrogen bond exists between the oxygen atom from salicylic acid moiety and nitrogen from the same moiety. A variety of solution studies were carried out for the determination of DNA binding mode of the complexes. The results suggest that both complexes bind to Herring sperm DNA via non intercalative mode.

  13. Synthesis, spectroscopic, crystal structure and DNA binding of Ru(II) complexes with 2-hydroxy-benzoic acid [1-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-ethylidene]-hydrazide.

    PubMed

    Chitrapriya, Nataraj; Kamatchi, Thangavel Sathiya; Zeller, Matthias; Lee, Hyosun; Natarajan, Karuppannan

    2011-10-15

    Reactions of 2-hydroxy-benzoic acid [1-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-ethylidene]-hydrazide (H(2)L) with [RuHCl(CO)(EPh(3))(3)] (E = P or As) were carried out and the new complexes obtained were characterized by elemental analysis, electronic, IR, (1)H NMR and (13)C NMR spectroscopic techniques and single crystal X-ray diffraction studies. Complex (1) crystallizes in the monoclinic space group P2(1)/c with unit cell dimensions a=18.6236(17) Å, b=12.8627(12) Å, c=21.683(2) Å, α=90.00, β=114.626(2), γ=90.00 V=4721.8(8) Å, Z=4. The crystal structure of the complex shows Ru(II) atom is six-coordinated, forming a slightly distorted octahedral geometry with two P atoms in axial positions, and three chelating donor atoms of the tridentate Schiff base ligand and one carbonyl group located in the equatorial plane. The molecular structure is stabilized by intramolecular O-H···N interactions. No intermolecular hydrogen bond was observed. The intramolecular hydrogen bond exists between the oxygen atom from salicylic acid moiety and nitrogen from the same moiety. A variety of solution studies were carried out for the determination of DNA binding mode of the complexes. The results suggest that both complexes bind to Herring sperm DNA via non intercalative mode. PMID:21763180

  14. Di-μ-hydroxido-bis­[hemiaqua­(N,N,N′,N′-tetra­methyl­ethane-1,2-diamine)­copper(II)] bis­(tetra­fluoridoborate)

    PubMed Central

    Haníková, Jaroslava; Kuchár, Juraj; Trávníček, Zdeněk; Černák, Juraj

    2012-01-01

    The title compound, [Cu2(OH)2(C6H16N2)2(H2O)](BF4)2, consists of dinuclear centrosymmetric [Cu2(OH)2(tmen)2(H2O)]2+ complex cations (tmen = N,N,N′,N′-tetra­methyl­ethane-1,2-diamine) and tetra­fluoridoborate anions. In the cation, the CuII atom shows a slightly distorted square-pyramidal coordination geometry provided by a pair of μ-OH− anions and by the N atoms of a chelate tmen ligand in the basal plane. The apical position is statistically occupied by the O atom of a half-occupancy water mol­ecule. The F atoms of the anion are disordered over three sets of sites with occupancies of 0.598 (9):0.269 (6):0.134 (8). The crystal packing is governed by ionic forces as well as by O—H⋯F hydrogen bonds. PMID:22719335

  15. Combined Theoretical and Experimental Study of Spin and Charge Dynamics on the Homodinuclear Complex [Ni2II(L-N4Me2)(emb)

    NASA Astrophysics Data System (ADS)

    Jin, W.; Rupp, F.; Chevalier, K.; Wolf, M. M. N.; Rojas, M. Colindres; Lefkidis, G.; Krüger, H.-J.; Diller, R.; Hübner, W.

    2012-12-01

    We present a combined theoretical and experimental study of spin and charge dynamics on the homodinuclear compound [Ni2II(L-N4Me2)(emb)]. The theoretically calculated oscillator strengths of the ground-state absorption spectrum show an acceptable agreement with experiment. We predict a local ultrafast laser-induced spin-flip scenario, which involves charge-transfer states. Experimentally, we observe charge dynamics on two different time scales. The two relevant, transient electronic states and their electronic properties are also theoretically characterized. These results provide a joint investigation of the homodinuclear complex and suggest a realistic scenario for ultrafast spin dynamics and other optical-related manipulations.

  16. Dicopper(II) anthraquinophanes as multielectron reservoirs for oxidation and reduction: a joint experimental and theoretical study.

    PubMed

    Castellano, María; Barros, Wdeson P; Acosta, Alvaro; Julve, Miguel; Lloret, Francesc; Li, Yanling; Journaux, Yves; De Munno, Giovanni; Armentano, Donatella; Ruiz-García, Rafael; Cano, Joan

    2014-10-20

    Two new dinuclear copper(II) metallacyclophanes with 1,4-disubstituted 9,10-anthraquinonebis(oxamate) bridging ligands are reported that can reversibly take and release electrons at the redox-active ligand and metal sites, respectively, to give the corresponding mono- and bis(semiquinonate and/or catecholate) Cu(II)2 species and mixed-valent Cu(II)/Cu(III) and high-valent Cu(III)2 ones. Density functional calculations allow us to give further insights on the dual ligand- and metal-based character of the redox processes in this novel family of antiferromagnetically coupled di- copper(II) anthraquinophanes. This unique ability for charge storage could be the basis for the development of new kinds of molecular spintronic devices, referred to as molecular magnetic capacitors (MMCs).

  17. Effects of captopril, telmisartan and bardoxolone methyl (CDDO-Me) in ischemia-reperfusion-induced acute kidney injury in rats: an experimental comparative study.

    PubMed

    Kocak, Cengiz; Kocak, Fatma Emel; Akcilar, Raziye; Bayat, Zeynep; Aras, Bekir; Metineren, Mehmet Huseyin; Yucel, Mehmet; Simsek, Hasan

    2016-02-01

    Renal ischemia-reperfusion (IR) injury is one of the most common causes of acute kidney injury. This study investigated the effects of captopril (CAP), telmisartan (TEL) and bardoxolone methyl (BM) in animals with renal IR injury. Adult male Wistar-Albino rats were divided into six groups: control, vehicle, IR, IR with CAP, IR with TEL and IR with BM. Before IR was induced, drugs were administered by oral gavage. After a 60-min ischemia and a 120-min reperfusion period, bilateral nephrectomies were performed. Serum urea, creatinine, neutrophil gelatinase-associated lipocalin (NGAL) levels, tissue total oxidant status (TOS), total antioxidant status (TAS), total thiol (TT), asymmetric dimethylarginine (ADMA) levels, superoxide dismutase (SOD) activity and glutathione peroxidase (GSH-Px) activity were measured. Tissue mRNA expression levels of peroxisome proliferator-activated receptor-ɣ (PPAR-ɣ), nuclear factor erythroid 2-related factor 2 (Nrf2) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) were analyzed. In addition, renal tissues were evaluated histopathologically and immunohistochemically. All tested drugs reduced renal damage, apoptosis, urea, creatinine, NGAL, TOS, nitric oxide (NO) and ADMA levels, NF-κB, inducible nitric oxide synthase (iNOS) and endothelin-1 (ET-1) expressions (P < 0.001). All tested drugs increased SOD activity, GSH-Px activity, TAS levels, TT levels, endothelial nitric oxide synthase (eNOS) expression, dimethylarginine dimethylaminohydrolases (DDAHs) expression, Nrf2 expression and PPAR-ɣ expression (P < 0.001, P < 0.003). These results suggest that CAP, TEL and BM pretreatment could reduce renal IR injury via anti-inflammatory, antioxidant and anti-apoptotic effects.

  18. Vascular and antioxidant effects of an aqueous Mentha cordifolia extract in experimental N(G)-nitro-L-arginine methyl ester-induced hypertension.

    PubMed

    Pakdeechote, Poungrat; Prachaney, Parichat; Berkban, Warinee; Kukongviriyapan, Upa; Kukongviriyapan, Veerapol; Khrisanapant, Wilaiwan; Phirawatthakul, Yada

    2014-01-01

    The effect of an aqueous Mentha cordifolia (MC) extract on the haemodynamic status, vascular remodeling, function, and oxidative status in NG-nitro-L-arginine methyl ester (L-NAME)-induced hypertension was investigated. Male Sprague-Dawley rats were given L-NAME [50 mg/(kg body weight (BW) d)] in their drinking water for 5 weeks and were treated by intragastric administration with the MC extract [200 mg/(kgBWd)] for 2 consecutive weeks. Quercetin [25 mg/(kg BW d)] was used as a positive control. The effects of the MC extract on the haemodynamic status, thoracic aortic wall thickness, and oxidative stress markers were determined, and the vasorelaxant activity of the MC extract was tested in isolated mesenteric vascular beds in rats. Significant increases in the mean arterial pressure (MAP), heart rate (HR), hind limb vascular resistance (HVR), wall thickness, and cross-sectional area of the thoracic aorta, as well as oxidative stress markers were found in the L-NAME-treated group compared to the control (P < 0.05). MAP, HVR, wall thickness, cross-sectional area of the thoracic aorta, plasma malondialdehyde (MDA), and vascular superoxide anion production were significantly reduced in L-NAME hypersensitive rats treated with the MC extract or quercetin. Furthermore, the MC extract induced vasorelaxation in the pre-constricted mesenteric vascular bed with intact and denuded endothelium of normotensive and hypertensive rats. Our results suggest that the MC extract exhibits an antihypertensive effect via its antioxidant capacity, vasodilator property, and reduced vascular remodeling.

  19. Synthesis, crystal structure, spectroscopic characterization and nonlinear optical properties of manganese (II) complex of picolinate: A combined experimental and computational study

    NASA Astrophysics Data System (ADS)

    Tamer, Ömer; Avcı, Davut; Atalay, Yusuf; Çoşut, Bünyemin; Zorlu, Yunus; Erkovan, Mustafa; Yerli, Yusuf

    2016-02-01

    A novel manganese (II) complex with picolinic acid (pyridine 2-carboxylic acid, Hpic), namely, [Mn(pic)2(H2O)2] was prepared and its crystal structure was fully characterized by using single crystal X-ray diffraction. Picolinate (pic) ligands were coordinated to the central manganese(II) ion as bidentate N,O-donors through the nitrogen atoms of pyridine rings and the oxygen atoms of carboxylate groups forming five-membered chelate rings. The spectroscopic characterization of Mn(II) complex was performed by the applications of FT-IR, Raman, UV-vis and EPR techniques. In order to support these studies, density functional theory (DFT) calculations were carried out by using B3LYP level. IR and Raman spectra were simulated at B3LYP level, and obtained results indicated that DFT calculations generally give compatible results to the experimental ones. The electronic structure of the Mn(II) complex was predicted using time dependent DFT (TD-DFT) method with polarizable continuum model (PCM). Molecular stability, hyperconjugative interactions, intramolecular charge transfer (ICT) and bond strength were investigated by applying natural bond orbital (NBO) analysis. Nonlinear optical properties of Mn(II) complex were investigated by the determining of molecular polarizability (α) and hyperpolarizability (β) parameters.

  20. Platelet aggregation responses and virus isolation from platelets in calves experimentally infected with type I or type II bovine viral diarrhea virus.

    PubMed

    Walz, P H; Bell, T G; Grooms, D L; Kaiser, L; Maes, R K; Baker, J C

    2001-10-01

    Altered platelet function has been reported in calves experimentally infected with type II bovine viral diarrhea virus (BVDV). The purpose of the present study was to further evaluate the ability of BVDV isolates to alter platelet function and to examine for the presence of a virus-platelet interaction during BVDV infection. Colostrum-deprived Holstein calves were obtained immediately after birth, housed in isolation, and assigned to 1 of 4 groups (1 control and 3 treatment groups). Control calves (n = 4) were sham inoculated, while calves in the infected groups (n = 4 for each group) were inoculated by intranasal instillation with 10(7) TCID50 of either BVDV 890 (type II), BVDV 7937 (type II), or BVDV TGAN (type I). Whole blood was collected prior to inoculation (day 0) and on days 4, 6, 8, 10, and 12 after inoculation for platelet function testing by optical aggregometry by using adenosine diphosphate and platelet activating factor. The maximum percentage aggregation and the slope of the aggregation curve decreased over time in BVDV-infected calves; however, statistically significant differences (Freidman repeated measures ANOVA on ranks, P < 0.05) were only observed in calves infected with the type II BVDV isolates. Bovine viral diarrhea virus was not isolated from control calves, but was isolated from all calves infected with both type II BVDV isolates from days 4 through 12 after inoculation. In calves infected with type I BVDV, virus was isolated from 1 of 4 calves on days 4 and 12 after inoculation and from all calves on days 6 and 8 after inoculation. Altered platelet function was observed in calves infected with both type II BVDV isolates, but was not observed in calves infected with type I BVDV. Altered platelet function may be important as a difference in virulence between type I and type II BVDV infection.

  1. The origins of atmospheric methyl mercury

    SciTech Connect

    Prestbo, E.M.; Bloom, N.S.

    1995-12-31

    Methyl Hg in precipitation shows strong regional patterns, with highest volume weighted mean values (0.4 ng/L) in the Pacific Northwest and lowest values in Florida (<0.01 ng/l). Over most of the North Central region, average values range from 0.05 to 0.2 ng/L. Several potential sources of methyl Hg to the atmosphere have been investigated, including direct anthropogenic emissions, atmospheric methylation of Hg{sup o} or Hg(II), and emissions of methyl or dimethyl Hg from natural surfaces (oceans, bogs, or forests). Direct measurements of major total Hg sources such as coal and waste combustors, and sewage treatment facilities suggest that direct anthropogenic emissions are an insignificant source of methyl Hg to the atmosphere. The gas phase reaction of methyl halides with Hg{sup o} also appears to be an insignificant source of methyl Hg to the atmosphere. Recent laboratory experiments have provided a likely mechanism for atmospheric Hg methylation via a complex reaction involving acetate, sulfite, and iron. From a series of field measurements, another source appears to be the degradation of dimethyl mercury emitted by the upwelling of deep ocean water.

  2. Use of experimental design for the purge-and-trap-gas chromatography-mass spectrometry determination of methyl tert.-butyl ether, tert.-butyl alcohol and BTEX in groundwater at trace level.

    PubMed

    Bianchi, F; Careri, M; Marengo, E; Musci, M

    2002-10-25

    An efficient method for the simultaneous determination of methyl tert.-butyl ether, tert.-butyl alcohol, benzene, toluene, ethylbenzene and xylene isomers in groundwater by purge-and-trap-gas chromatography-mass spectrometry was developed and validated. Experimental design was used to investigate the effects of temperature of extraction, time of extraction and percentage of salt added to the water samples. Regression models and desirability functions were applied to find the experimental conditions providing the highest global extraction yield. Validation was carried out in terms of limits of detection (LOD), limits of quantitation (LOQ), linearity and precision. LOD values ranging from 2.6 to 23 ng l(-1) were achieved, whereas linearity was statistically verified over two orders of magnitude for each compound. Precision was evaluated testing two concentration levels. Good results were obtained both in terms of intra-day repeatability and intermediate precision: RSD% lower than 4.5% at the highest concentration and lower than 13% at the lowest one were calculated for intra-day repeatability. A groundwater sample suspected of contamination by leaking underground petroleum storage tanks was analysed and some of the analytes were detected and quantitated.

  3. An investigation of possible competing mechanisms for Ni-containing methyl-coenzyme M reductase.

    PubMed

    Chen, Shi-Lu; Blomberg, Margareta R A; Siegbahn, Per E M

    2014-07-21

    Ni-containing methyl-coenzyme M reductase (MCR) is capable of catalyzing methane formation from methyl-coenzyme M (CH3-SCoM) and coenzyme B (CoB-SH), and also its reverse reaction (methane oxidation). Based on extensive experimental and theoretical investigations, it has turned out that a mechanism including an organometallic methyl-Ni(III)F430 intermediate is inaccessible, while another mechanism involving a methyl radical and a Ni(II)-SCoM species currently appears to be the most acceptable one for MCR. In the present paper, using hybrid density functional theory and an active-site model based on the X-ray crystal structure, two other mechanisms were studied and finally also ruled out. One of them, involving proton binding on the CH3-SCoM substrate, which should facilitate methyl-Ni(III)F430 formation, is demonstrated to be quite unfavorable since the substrate has a much smaller proton affinity than the F430 cofactor. Another one (oxidative addition mechanism) is also shown to be unfavorable for the MCR reaction, due to the large endothermicity for the formation of the ternary intermediate with side-on C-S (for CH3-SCoM) or C-H (for methane) coordination to Ni.

  4. Experimental analysis and mathematical prediction of Cd(II) removal by biosorption using support vector machines and genetic algorithms.

    PubMed

    Hlihor, Raluca Maria; Diaconu, Mariana; Leon, Florin; Curteanu, Silvia; Tavares, Teresa; Gavrilescu, Maria

    2015-05-25

    We investigated the bioremoval of Cd(II) in batch mode, using dead and living biomass of Trichoderma viride. Kinetic studies revealed three distinct stages of the biosorption process. The pseudo-second order model and the Langmuir model described well the kinetics and equilibrium of the biosorption process, with a determination coefficient, R(2)>0.99. The value of the mean free energy of adsorption, E, is less than 16 kJ/mol at 25 °C, suggesting that, at low temperature, the dominant process involved in Cd(II) biosorption by dead T. viride is the chemical ion-exchange. With the temperature increasing to 40-50 °C, E values are above 16 kJ/mol, showing that the particle diffusion mechanism could play an important role in Cd(II) biosorption. The studies on T. viride growth in Cd(II) solutions and its bioaccumulation performance showed that the living biomass was able to bioaccumulate 100% Cd(II) from a 50 mg/L solution at pH 6.0. The influence of pH, biomass dosage, metal concentration, contact time and temperature on the bioremoval efficiency was evaluated to further assess the biosorption capability of the dead biosorbent. These complex influences were correlated by means of a modeling procedure consisting in data driven approach in which the principles of artificial intelligence were applied with the help of support vector machines (SVM), combined with genetic algorithms (GA). According to our data, the optimal working conditions for the removal of 98.91% Cd(II) by T. viride were found for an aqueous solution containing 26.11 mg/L Cd(II) as follows: pH 6.0, contact time of 3833 min, 8 g/L biosorbent, temperature 46.5 °C. The complete characterization of bioremoval parameters indicates that T. viride is an excellent material to treat wastewater containing low concentrations of metal.

  5. Experimental analysis and mathematical prediction of Cd(II) removal by biosorption using support vector machines and genetic algorithms.

    PubMed

    Hlihor, Raluca Maria; Diaconu, Mariana; Leon, Florin; Curteanu, Silvia; Tavares, Teresa; Gavrilescu, Maria

    2015-05-25

    We investigated the bioremoval of Cd(II) in batch mode, using dead and living biomass of Trichoderma viride. Kinetic studies revealed three distinct stages of the biosorption process. The pseudo-second order model and the Langmuir model described well the kinetics and equilibrium of the biosorption process, with a determination coefficient, R(2)>0.99. The value of the mean free energy of adsorption, E, is less than 16 kJ/mol at 25 °C, suggesting that, at low temperature, the dominant process involved in Cd(II) biosorption by dead T. viride is the chemical ion-exchange. With the temperature increasing to 40-50 °C, E values are above 16 kJ/mol, showing that the particle diffusion mechanism could play an important role in Cd(II) biosorption. The studies on T. viride growth in Cd(II) solutions and its bioaccumulation performance showed that the living biomass was able to bioaccumulate 100% Cd(II) from a 50 mg/L solution at pH 6.0. The influence of pH, biomass dosage, metal concentration, contact time and temperature on the bioremoval efficiency was evaluated to further assess the biosorption capability of the dead biosorbent. These complex influences were correlated by means of a modeling procedure consisting in data driven approach in which the principles of artificial intelligence were applied with the help of support vector machines (SVM), combined with genetic algorithms (GA). According to our data, the optimal working conditions for the removal of 98.91% Cd(II) by T. viride were found for an aqueous solution containing 26.11 mg/L Cd(II) as follows: pH 6.0, contact time of 3833 min, 8 g/L biosorbent, temperature 46.5 °C. The complete characterization of bioremoval parameters indicates that T. viride is an excellent material to treat wastewater containing low concentrations of metal. PMID:25224921

  6. Crystal structure of bis(bis{(E)-[(6-{(E)-[(4-fluorobenzyl)imino]methyl}pyridin-2-yl)methylidene](4-fluorophenyl)amine}nickel(II)) tetra-bromide nona-hydrate.

    PubMed

    Basaran, Ismet; Rhaman, Md Mhahabubur; Powell, Douglas R; Hossain, Md Alamgir

    2015-12-01

    In the title complex, [Ni(C21H17F2N3)2]2Br4·9H2O, there are two independent metal complexes per asymmetric unit and two ligands per metal complex. The structural features (bond lengths and angles) of the two complexes are almost identical. In each complex, the nickel(II) ion is coordinated in an octa-hedral environment by six N atoms from two chelating (9E)-N-({6-[(E)-(4-fluoro-benzyl-imino)-meth-yl]pyridin-2-yl}methyl-ene)(4-fluoro-phen-yl)methanammine ligands. The Ni-N bond lengths range from 1.973 (2) to 2.169 (2) Å, while the chelate N-Ni-N angles range from 77.01 (10) to 105.89 (9)°. Additionally, there are four bromide anions and nine solvent water mol-ecules within the asymmetric unit. The water mol-ecules form a hydrogen-bonded network, displaying C-H⋯O, C-H⋯Br, O-H⋯Br, O-H⋯O and O-H⋯F inter-actions into layers parallel to (111). In each unit, the fluoro-phenyl rings of one ligand are stacked with the central ring of the other ligand via π-π inter-actions, with the closest centroid-to-plane distances being 3.445 (5), 3.636 (5), 3.397 (5) and 3.396 (5) Å. PMID:26870437

  7. Developmental regulation of alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor subunit expression in forebrain and relationship to regional susceptibility to hypoxic/ischemic injury. II. Human cerebral white matter and cortex.

    PubMed

    Talos, Delia M; Follett, Pamela L; Folkerth, Rebecca D; Fishman, Rachel E; Trachtenberg, Felicia L; Volpe, Joseph J; Jensen, Frances E

    2006-07-01

    This report is the second of a two-part evaluation of developmental differences in alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor (AMPAR) subunit expression in cell populations within white matter and cortex. In part I, we reported that, in rat, developmental expression of Ca2+-permeable (GluR2-lacking) AMPARs correlated at the regional and cellular level with increased susceptibility to hypoxia/ischemia (H/I), suggesting an age-specific role of these receptors in the pathogenesis of brain injury. Part II examines the regional and cellular progression of AMPAR subunits in human white matter and cortex from midgestation through early childhood. Similarly to the case in the rodent, there is a direct correlation between selective vulnerability to H/I and expression of GluR2-lacking AMPARs in human brain. For midgestational cases aged 20-24 postconceptional weeks (PCW) and for premature infants (25-37 PCW), we found that radial glia, premyelinating oligodendrocytes, and subplate neurons transiently expressed GluR2-lacking AMPARs. Notably, prematurity represents a developmental window of selective vulnerability for white matter injury, such as periventricular leukomalacia (PVL). During term (38-42 PCW) and postterm neonatal (43-46 PCW) periods, age windows characterized by increased susceptibility to cortical injury and seizures, GluR2 expression was low in the neocortex, specifically on cortical pyramidal and nonpyramidal neurons. This study indicates that Ca2+-permeable AMPAR blockade may represent an age-specific therapeutic strategy for potential use in humans. Furthermore, these data help to validate specific rodent maturational stages as appropriate models for evaluation of H/I pathophysiology.

  8. Crystal structure of bis(bis{(E)-[(6-{(E)-[(4-fluorobenzyl)imino]methyl}pyridin-2-yl)methylidene](4-fluorophenyl)amine}nickel(II)) tetra­bromide nona­hydrate

    PubMed Central

    Basaran, Ismet; Rhaman, Md Mhahabubur; Powell, Douglas R.; Hossain, Md. Alamgir

    2015-01-01

    In the title complex, [Ni(C21H17F2N3)2]2Br4·9H2O, there are two independent metal complexes per asymmetric unit and two ligands per metal complex. The structural features (bond lengths and angles) of the two complexes are almost identical. In each complex, the nickel(II) ion is coordinated in an octa­hedral environment by six N atoms from two chelating (9E)-N-({6-[(E)-(4-fluoro­benzyl­imino)­meth­yl]pyridin-2-yl}methyl­ene)(4-fluoro­phen­yl)methanammine ligands. The Ni—N bond lengths range from 1.973 (2) to 2.169 (2) Å, while the chelate N—Ni—N angles range from 77.01 (10) to 105.89 (9)°. Additionally, there are four bromide anions and nine solvent water mol­ecules within the asymmetric unit. The water mol­ecules form a hydrogen-bonded network, displaying C—H⋯O, C—H⋯Br, O—H⋯Br, O—H⋯O and O—H⋯F inter­actions into layers parallel to (111). In each unit, the fluoro­phenyl rings of one ligand are stacked with the central ring of the other ligand via π–π inter­actions, with the closest centroid-to-plane distances being 3.445 (5), 3.636 (5), 3.397 (5) and 3.396 (5) Å. PMID:26870437

  9. Synthesis, crystal structures, and biological evaluation of Cu(II) and Zn(II) complexes of 2-benzoylpyridine Schiff bases derived from S-methyl- and S-phenyldithiocarbazates.

    PubMed

    Li, Ming Xue; Zhang, Li Zhi; Chen, Chun Ling; Niu, Jing Yang; Ji, Bian Sheng

    2012-01-01

    Two NNS tridentate Schiff base ligands of 2-benzoylpyridine S-methyldithiocarbazate (HL(1)) and 2-benzoylpyridine S-phenyldithiocarbazate (HL(2)) and their transition metal complexes [Cu(2)(L(1))(2)(CH(3)COO)](ClO(4)) (1), [Zn(2)(L(1))(2)(ClO(4))(2)] (2), [Zn(L(2))(2)](3) have been prepared and characterized by elemental analysis, IR, MS, NMR and single-crystal X-ray diffraction studies. In the solid state, each of two Schiff bases remains in its thione tautomeric form with the thione sulfur atom trans to the azomethine nitrogen atom. Under similar prepared conditions, three new complexes showed distinctly different coordination modes depending on their coordinating preferences. Each copper atom in S-bridged dinuclear complex [Cu(2)(L(1))(2)(CH(3)COO)](ClO(4)) (1) is surrounded by five donor atoms in a square-pyramidal fashion (4+1). [Zn(2)(L(1))(2)(ClO(4))(2)] (2) is a dimer in which each zinc atom adopts a seven-coordinate distorted pentagonal bipyramidal geometry, while mononuclear [Zn(L(2))(2)] (3) has octahedral coordination geometry. Biological studies, carried out in vitro against selected bacteria, fungi, and K562 leukaemia cell line, respectively, have shown that different substituted groups attached at the dithiocarbazate moieties and metals showed distinctive differences in the biological property. Zinc(II) complexes 2 and 3 could distinguish K562 leukaemia cell line from normal hepatocyte QSG7701 cell line. Effect of the title compounds on Mitochondria membrane potential (MMP) and PI-associated fluorescence intensity in K562 leukaemia cell line are also studied. The title compounds may exert their cytotoxicity activity via induced loss of MMP. PMID:22112848

  10. Experimental and theoretical analyses of penetration processes of externally applied rotating helical magnetic perturbation fields in TEXTOR and HYBTOK-II

    NASA Astrophysics Data System (ADS)

    Kikuchi, Y.; de Bock, M. F. M.; Finken, K. H.; Jakubowski, M.; Jaspers, R.; Koslowski, H. R.; Kraemer-Flecken, A.; Lehnen, M.; Liang, Y.; Loewenbrueck, K.; Matsunaga, G.; Reiser, D.; Samm, U.; Sewell, G.; Takamura, S.; Unterberg, B.; Wolf, R. C.; Zimmermann, O.; TEXTOR-team

    2007-05-01

    Penetration processes of rotating helical magnetic perturbation field into tokamak plasmas have been investigated by the dynamic ergodic divertor (DED) in TEXTOR. Experimental observations of the field penetration and field amplification are performed and the data are interpreted by theoretical analyses based on a linearized two-fluid plasma model. It is observed that the growth of the forced magnetic reconnection by the rotating DED-field is accompanied by a change in the plasma fluid rotation. The theoretical model is also applied to the DED experiment in the small tokamak device HYBTOK-II. It is confirmed that the theoretical analyses can explain the observed radial profiles of the DED-field in the plasma by inserting small magnetic pick-up coils in HYBTOK-II.

  11. Unique mononuclear Mn(II) complexes of an end-off compartmental Schiff base ligand: experimental and theoretical studies on their bio-relevant catalytic promiscuity.

    PubMed

    Adhikary, Jaydeep; Chakraborty, Aratrika; Dasgupta, Sanchari; Chattopadhyay, Shyamal Kumar; Kruszynski, Rafał; Trzesowska-Kruszynska, Agata; Stepanović, Stepan; Gruden-Pavlović, Maja; Swart, Marcel; Das, Debasis

    2016-08-01

    Three new mononuclear manganese(ii) complexes, namely [Mn(HL)2]·2ClO4 (1), [Mn(HL)(N(CN)2)(H2O)2]·ClO4 (2) and [Mn(HL)(SCN)2] (3) [LH = 4-tert-butyl-2,6-bis-[(2-pyridin-2-yl-ethylimino)-methyl]-phenol], have been synthesized and structurally characterized. An "end-off" compartmental ligand (LH) possesses two symmetrical compartments with N2O binding sites but accommodates only one manganese atom instead of two due to the protonation of the imine nitrogen of one compartment. Although all three complexes are mononuclear, complex 1 is unique as it has a 1 : 2 metal to ligand stoichiometry. The catalytic promiscuity of complexes 1-3 in terms of two different bio-relevant catalytic activities namely catecholase and phenoxazinone synthase has been thoroughly investigated. EPR and cyclic voltametric studies reveal that radical formation rather than metal centered redox participation is responsible for their catecholase-like and phenoxazinone synthase-like catalytic activity. A computational approach suggests that imine bond bound radical generation rather than phenoxo radical formation is most likely responsible for the oxidizing properties of the complexes. PMID:27430642

  12. A new tridentate Schiff base Cu(II) complex: Synthesis, experimental and theoretical studies on its crystal structure, FT-IR and UV-Visible spectra

    NASA Astrophysics Data System (ADS)

    Saheb, Vahid; Sheikhshoaie, Iran; Setoodeh, Nasim; Rudbari, Hadi Amiri; Bruno, Giuseppe

    2013-06-01

    A new Cu(II) complex [Cu(L)(NCS)] has been synthesized, using 1-(N-salicylideneimino)-2-(N,N-methyl)-aminoethane as tridentate ONN donor Schiff base ligand (HL). The dark green crystals of the compound are used for single-crystal X-ray analysis and measuring Fourier Transform Infrared (FT-IR) and UV-Visible spectra. Electronic structure calculations at the B3LYP and MP2 levels of theory are performed to optimize the molecular geometry and to calculate the UV-Visible and FT-IR spectra of the compound. Vibrational assignments and analysis of the fundamental modes of the compound are performed. Time-dependent density functional theory (TD-DFT) method is used to calculate the electronic transitions of the complex. A scaling factor of 1.015 is obtained for vibrational frequencies computed at the B3LYP level using basis sets 6-311G(d,p). It is found that solvent has a profound effect on the electronic absorption spectrum. The UV-Visible spectrum of the complex recorded in DMSO and DMF solution can be correctly predicted by a model in which DMSO and DMF molecules are coordinated to the central Cu atom via their oxygen atoms.

  13. Comparative photo-release of nitric oxide from isomers of substituted terpyridinenitrosylruthenium(II) complexes: experimental and computational investigations.

    PubMed

    Akl, Joëlle; Sasaki, Isabelle; Lacroix, Pascal G; Malfant, Isabelle; Mallet-Ladeira, Sonia; Vicendo, Patricia; Farfán, Norberto; Santillan, Rosa

    2014-09-01

    The 4'-(2-fluorenyl)-2,2':6',2''-terpyridine (FT) ligand and its cis(Cl,Cl)- and trans(Cl,Cl)-[Ru(II)(FT)Cl2(NO)](PF6) complexes have been synthesized. Both isomers were separated by HPLC and fully characterized by (1)H and (13)C NMR. The X-ray diffraction crystal structures were solved for FT (Pna21 space group, a = 34.960(4), b = 5.9306(7), c = 9.5911(10) Å), and trans(Cl,Cl)-[Ru(II)(FT)Cl2(NO)](PF6)·MeOH (P1[combining macron] space group, a = 10.3340(5), b = 13.0961(6), c = 13.2279(6) Å, α = 72.680(2), β = 70.488(2), γ = 67.090(2)°). Photo-release of NO˙ radicals occurs under irradiation at 405 nm, with a quantum yield of 0.31 and 0.10 for cis(Cl,Cl)-[Ru(II)(FT)Cl2(NO)](PF6) and trans(Cl,Cl)-[Ru(II)(FT)Cl2(NO)](PF6), respectively. This significant difference is likely due to the trans effect of Cl(-), which favors the photo-release. UV-visible spectroscopy and cyclic voltammetry indicate the formation of ruthenium(iii) species as photoproducts. A density functional theory (DFT) analysis provides a rationale for the understanding of the photo-physical properties, and allows relating the weakening of the Ru-NO bond, and finally the photo-dissociation, to HOMO → LUMO excitations.

  14. Experimental Study of Crossing-Angle and Parasitic Effects at the PEP-II e+e- Collider

    SciTech Connect

    Kozanecki, W.; Narsky, Ilya V.; Cai, Y.; Seeman, J.T.; Sullivan, M.; /SLAC

    2005-10-07

    In a series of dedicated accelerator experiments, we measure the dependence of the PEP-II luminosity performance on small horizontal crossing angles and on the horizontal separation at the first parasitic crossing. The experiment is carried out by varying the IP angle of one of the beams in two different bunch patterns, one with and one without parasitic crossings. The measurements show satisfactory agreement with three-dimensional beam-beam simulations.

  15. Determination of calibration constants for the hole-drilling residual stress measurement technique applied to orthotropic composites. II - Experimental evaluations

    NASA Technical Reports Server (NTRS)

    Prasad, C. B.; Prabhakaran, R.; Tompkins, S.

    1987-01-01

    The first step in the extension of the semidestructive hole-drilling technique for residual stress measurement to orthotropic composite materials is the determination of the three calibration constants. Attention is presently given to an experimental determination of these calibration constants for a highly orthotropic, unidirectionally-reinforced graphite fiber-reinforced polyimide composite. A comparison of the measured values with theoretically obtained ones shows agreement to be good, in view of the many possible sources of experimental variation.

  16. Stability hierarchy between Piracetam forms I, II, and III from experimental pressure-temperature diagrams and topological inferences.

    PubMed

    Toscani, Siro; Céolin, René; Minassian, Léon Ter; Barrio, Maria; Veglio, Nestor; Tamarit, Josep-Lluis; Louër, Daniel; Rietveld, Ivo B

    2016-01-30

    The trimorphism of the active pharmaceutical ingredient piracetam is a famous case of polymorphism that has been frequently revisited by many researchers. The phase relationships between forms I, II, and III were ambiguous because they seemed to depend on the heating rate of the DSC and on the history of the samples or they have not been observed at all (equilibrium II-III). In the present paper, piezo-thermal analysis and high-pressure differential thermal analysis have been used to elucidate the positions of the different solid-solid and solid-liquid equilibria. The phase diagram, involving the three solid phases, the liquid phase and the vapor phase, has been constructed. It has been shown that form III is the high-pressure, low-temperature form and the stable form at room temperature. Form II is stable under intermediary conditions and form I is the low pressure, high temperature form, which possesses a stable melting point. The present paper demonstrates the strength of the topological approach based on the Clapeyron equation and the alternation rule when combined with high-pressure measurements.

  17. Stability hierarchy between Piracetam forms I, II, and III from experimental pressure-temperature diagrams and topological inferences.

    PubMed

    Toscani, Siro; Céolin, René; Minassian, Léon Ter; Barrio, Maria; Veglio, Nestor; Tamarit, Josep-Lluis; Louër, Daniel; Rietveld, Ivo B

    2016-01-30

    The trimorphism of the active pharmaceutical ingredient piracetam is a famous case of polymorphism that has been frequently revisited by many researchers. The phase relationships between forms I, II, and III were ambiguous because they seemed to depend on the heating rate of the DSC and on the history of the samples or they have not been observed at all (equilibrium II-III). In the present paper, piezo-thermal analysis and high-pressure differential thermal analysis have been used to elucidate the positions of the different solid-solid and solid-liquid equilibria. The phase diagram, involving the three solid phases, the liquid phase and the vapor phase, has been constructed. It has been shown that form III is the high-pressure, low-temperature form and the stable form at room temperature. Form II is stable under intermediary conditions and form I is the low pressure, high temperature form, which possesses a stable melting point. The present paper demonstrates the strength of the topological approach based on the Clapeyron equation and the alternation rule when combined with high-pressure measurements. PMID:26617316

  18. Comparison of new experimental and atrophysical f-values for some Ru II lines, observed in HST spectra of chi Lupi

    NASA Technical Reports Server (NTRS)

    Johansson, Sveneric G.; Joueizadeh, Ali; Litzen, Ulf; Larsson, Jorgen; Persson, Anders; Wahlstrom, Claes-Goran; Svanberg, Sune; Leckrone, David S.; Wahlgren, Glenn M.

    1994-01-01

    We report an experimental absolute oscillator strengths for 18 UV lines of Ru II, obtained by combining laser-induced flourescence measurements of radiative lifetimes and branching fractions from line intensities in a calibrated Fourier-transform spectrum Hubble Space Telescope/Goddard High Resolution Spectrograph (HST/GHRS) observations of the spectrum of the sharp-lined B star chi Lupi contain six of these lines, for which 'astrophysical' relative f-values have been determined. The agreement is within 0.10 dex for a Ru abundance of log N(Ru)/N(H) = -7.90, which is 2.3 dex above the solar abundance.

  19. Syphilis and human experimentation from the first appearance of the disease to World War II: a historical perspective and reflections on ethics.

    PubMed

    Cuerda-Galindo, E; Sierra-Valentí, X; González-López, E; López-Muñoz, F

    2014-10-01

    Physicians have conducted research on syphilis for centuries, seeking to understand its etiology and the means of transmission as well as find ways to prevent and cure the disease. Their research practices often strayed from today's ethical standards. In this paper we review ethical aspects of the long history of research on syphilis with emphasis on the experiments performed in the 20th century. The description of research around the time of World War II covers medical experiments carried out in US prisons and in the experimentation centers established by Japanese doctors in occupied territory, as well as experiments in Nazi Germany and the treatment of syphilitics there. PMID:24268559

  20. Syphilis and human experimentation from the first appearance of the disease to World War II: a historical perspective and reflections on ethics.

    PubMed

    Cuerda-Galindo, E; Sierra-Valentí, X; González-López, E; López-Muñoz, F

    2014-10-01

    Physicians have conducted research on syphilis for centuries, seeking to understand its etiology and the means of transmission as well as find ways to prevent and cure the disease. Their research practices often strayed from today's ethical standards. In this paper we review ethical aspects of the long history of research on syphilis with emphasis on the experiments performed in the 20th century. The description of research around the time of World War II covers medical experiments carried out in US prisons and in the experimentation centers established by Japanese doctors in occupied territory, as well as experiments in Nazi Germany and the treatment of syphilitics there.

  1. The Experimental Degradation of Microorganisms Exposed to Mn(II) and SiO2 Over Time

    NASA Astrophysics Data System (ADS)

    Schelble, R. T.; Hall, J. A.; Fogel, M. L.; Jahnke, L. L.; Nealson, K. H.; Steele, A.

    2005-12-01

    The sedimentary origin of early Proterozoic massive manganese deposits in the geological record is often attributed in part to the impact of biological processes. Although it seems possible that widespread algal blooms in near-shore oceanic environments caused the oxidation of reduced manganese from ocean waters, direct evidence of microorganisms (i.e. microfossils or chemical biosignatures) have not been identified in early Proterozoic manganiferous deposits. The purpose of this study was to identify the potential for biosignature preservation in remnant ancient manganese deposits by monitoring the degradation of modern microorganisms exposed to varying concentrations of Mn(II). Given that most early Proterozoic microfossils have been found in siliceous rocks, similar experiments were carried out using silica-rich solutions for comparison. Bacillus subtilis (gram-positive) and Escherichia coli (gram-negative) were exposed to various Mn(II)- and silica-rich solutions over a period of 180 days. The degradation of a short-duration biomarker (DNA), and longer-duration biomarkers (phospholipid fatty acids and their derivative n-alkanes) were investigated. The degradation of DNA was quantified using real time PCR (RT-PCR) and microorganism specific and general bacteria primers. DNA longevity decreased with higher concentrations of manganese (up to 1000 ppm Mn(II)) when compared with control microorganisms suspended in solutions without manganese. This effect was more dramatic in the E. coli incubations. Relatively steady decreases in the longevity of B. subtilis DNA were observed when cells were exposed to Mn(II). This may be due to the ability of the organism to sporulate, which may protect the DNA from rapid degradation. B. subtilis DNA persisted longer when cells were exposed to undersaturated SiO2 solution (100 ppm SiO2), than those exposed to supersaturated SiO2 solutions (1000 ppm and 3000 ppm). The preservation potential of E. coli DNA showed no differences

  2. Task I: Dark Matter Search Experiments with Cryogenic Detectors: CDMS-I and CDMS-II Task II: Experimental Study of Neutrino Properties: EXO and KamLAND

    SciTech Connect

    Cabrera, Blas; Gratta, Giorgio

    2013-08-30

    Dark Matter Search - During the period of performance, our group continued the search for dark matter in the form of weakly interacting massive particles or WIMPs. As a key member of the CDMS (Cryogenic Dark Matter Search) collaboration, we completed the CDMS II experiment which led the field in sensitivity for more than five years. We fabricated all detectors, and participated in detector testing and verification. In addition, we participated in the construction and operation of the facility at the Soudan Underground Laboratory and played key roles in the data acquisition and analysis. Towards the end of the performance period, we began operating the SuperCDMS Soudan experiment, which consists of 15 advanced Ge (9 kg) detectors. The advanced detector design called iZIP grew out of our earlier DOE Particle Detector R&D program which demonstrated the rejection of surface electrons to levels where they are no longer the dominant source of background. Our group invented this advanced design and these larger detectors were fabricated on the Stanford campus in collaboration with the SLAC CDMS group and the Santa Clara University group. The sensitivity reach is expected to be up to 5 times better than CDMS II after two years of operation. We will check the new limits on WIMPs set by XENON100, and we expect improved sensitivity for light mass WIMPs beyond that of any other existing experiment. Our group includes the Spokesperson for SuperCDMS and continues to make important contributions to improvements in the detector technology which are enabling the very low trigger thresholds used to explore the low mass WIMP region. We are making detailed measurements of the charge transport and trapping within Ge crystals, measuring the diffusive trapping distance of the quasiparticle excitations within the Al phonon collector fins on the detector surface, and we are contributing to the development of much improved detector Monte Carlos which are essential to guide the detector

  3. Pyroprocessing of Oxidized Sodium-Bonded Fast Reactor Fuel -- an Experimental Study of Treatment Options for Degraded EBR-II Fuel

    SciTech Connect

    S. D. Herrmann; L. A. Wurth; N. J. Gese

    2013-09-01

    An experimental study was conducted to assess pyrochemical treatment options for degraded EBR-II fuel. As oxidized material, the degraded fuel would need to be converted back to metal to enable electrorefining within an existing electrometallurgical treatment process. A lithium-based electrolytic reduction process was studied to assess the efficacy of converting oxide materials to metal with a particular focus on the impact of zirconium oxide and sodium oxide on this process. Bench-scale electrolytic reduction experiments were performed in LiCl-Li2O at 650 °C with combinations of manganese oxide (used as a surrogate for uranium oxide), zirconium oxide, and sodium oxide. The experimental study illustrated how zirconium oxide and sodium oxide present different challenges to a lithium-based electrolytic reduction system for conversion of select metal oxides to metal.

  4. Bacopa monnieri Phytochemicals Mediated Synthesis of Platinum Nanoparticles and Its Neurorescue Effect on 1-Methyl 4-Phenyl 1,2,3,6 Tetrahydropyridine-Induced Experimental Parkinsonism in Zebrafish

    PubMed Central

    Nellore, Jayshree; Pauline, Cynthia; Amarnath, Kanchana

    2013-01-01

    Current discovery demonstrates the rapid formation of platinum nanoparticles using leaf extract of a neurobeneficial plant, Bacopa monnieri (BmE). The nanoparticles (BmE-PtNPs) were stabilized and then coated with varied phytochemicals present within the leaf extract. These nanoparticles demonstrated the same activity of Complex I, as that of oxidizing NADH to NAD+ using a spectrophotometric method. This suggests that BmE-PtNPs are a potential medicinal substance for oxidative stress mediated disease with suppressed mitochondrial complex I, namely, Parkinson's disease (PD). Hence, the neuroprotective potentials of the phytochemical coated nanoparticle were explored in 1-methyl 4-phenyl 1,2,3,6 tetrahydropyridine- (MPTP-)induced experimental Parkinsonism in zebrafish model. BmE-PtNPs pretreatment significantly reversed toxic effects of MPTP by increasing the levels of dopamine, its metabolites, GSH and activities of GPx, catalase, SOD and complex I, and reducing levels of MDA along with enhanced locomotor activity. Taken together, these findings suggest that BmE-PtNPs have protective effect in MPTP-induced neurotoxicity in this model of Parkinson's disease via their dual functions as mitochondrial complex I and antioxidant activity. PMID:26317003

  5. Theoretical and experimental studies of two Co(II) and Ni(II) coordination complex with N,O donor 2-chloro-6-{[(4-hydroxy-3-methoxyphenyl)methylidene]amino}-4 nitrophenol ligand

    NASA Astrophysics Data System (ADS)

    Kusmariya, Brajendra S.; Tiwari, Sandeep; Tiwari, Anjali; Mishra, A. P.; Naikoo, Gowhar Ahmad; Pandit, Umar J.

    2016-07-01

    Here we report two mononuclear Co(II) and Ni(II) complexes of general formula [M(L)2(H2O)].2H2O; {M = CoII & NiII} derived from bidentate 2-chloro-6-{[(4-hydroxy-3-methoxyphenyl)methylidene]amino}-4 nitrophenol ligand (HL). These compounds were characterized by elemental analysis, spectral (FT-IR, electronic and 1H-NMR), molar conductance, thermal, PXRD, SEM and electrochemical studies. Distorted octahedral geometry was proposed around the metal center with ligand (HL). The PXRD and SEM analysis shows the crystalline nature of complexes. The broadening of diffraction peaks were explained in terms of domain size and the lattice strain according to Scherrer and Williamson-Hall method. TG of the synthesized complexes illustrates their general decomposition pattern and thermal stability. The kinetic and thermodynamic parameters viz. activation energy (E∗), pre-exponential factor (Z), entropy of activation (ΔS∗), enthalpy of activation (ΔH∗) and free energy of activation (ΔG∗) of degradation process were also evaluated using Coats-Redfern (C-R), Piloyan-Novikova (P-N) and Horowitz-Metzger (H-M) methods for both complexes assuming first order degradation. The optical band gap values of complexes were found to be in good agreement with calculated HOMO-LUMO energy gap (ΔE) and lie in semiconducting range. The cyclic voltammetric studies of synthesized compounds were carried out in order to examine their electrochemical behavior. In addition theoretical calculations by means of DFT at B3LYP level were incorporated to support the experimental findings.

  6. Hydrodynamic Impact of a System with a Single Elastic Mode II : Comparison of Experimental Force and Response with Theory

    NASA Technical Reports Server (NTRS)

    Miller, Robert W; Merten, Kenneth F

    1952-01-01

    Hydrodynamic impact tests were made on an elastic model approximating a two-mass spring system to determine experimentally the effects of structural flexibility on the hydrodynamic loads encountered during seaplane landing impacts and to correlate the results with theory. A flexible seaplane was represented by a two-mass spring system consisting of a rigid prismatic float connected to a rigid upper mass by an elastic structure. The model had a ratio of sprung mass to hull mass of 0.6 and a natural frequency of 3.0 cycles per second. The tests were conducted in smooth water at fixed trims and included both high and low flight-path angles and a range of velocity. Theoretical and experimental comparisons indicated that the theoretical results agreed well with the experimental results.

  7. Morphology-dependent stimulated Raman scattering imaging. II. Experimental studies of solvent structure in the diffuse electric double layer

    NASA Astrophysics Data System (ADS)

    Zhang, Jian-Xiang; Moortgat, Philip A.; Aker, Pamela M.

    1996-11-01

    Experimental confirmation that morphology-dependent stimulated Raman scattering can be used as an optical imaging technique is given. The water structure variations present at a charged water/air interface have been mapped. The measured structure variations track precisely that given by the Gouy-Chapman theory. We present, to our knowledge, the first experimental investigations of water solvent response in the diffuse part of the electric double layer. Imaging experiments on droplets charged to both positive and negative values have enabled us to determine the neutral water/air interface potential.

  8. Morphology-dependent stimulated Raman scattering imaging. II. Experimental studies of solvent structure in the diffuse electric double layer

    SciTech Connect

    Zhang, J.; Moortgat, P.A.; Aker, P.M.

    1996-11-01

    Experimental confirmation that morphology-dependent stimulated Raman scattering can be used as an optical imaging technique is given. The water structure variations present at a charged water/air interface have been mapped. The measured structure variations track precisely that given by the Gouy{endash}Chapman theory. We present, to our knowledge, the first experimental investigations of water solvent response in the diffuse part of the electric double layer. Imaging experiments on droplets charged to both positive and negative values have enabled us to determine the neutral water/air interface potential. {copyright} {ital 1996 American Institute of Physics.}

  9. A STUDY OF FUNDAMENTAL REACTION PATHWAYS FOR TRANSITION METAL ALKYL COMPLEXES. I. THE REACTION OF A NICKEL METHYL COMPLEX WITH ALKYNES. II. THE MECHANISM OF ALDEHYDE FORMATION IN THE REACTION OF A MOLYBDENUM HYDRIDE WITH MOLYBDENUM ALKYLS

    SciTech Connect

    Huggins, John Mitchell

    1980-06-01

    I. This study reports the rapid reaction under mild conditions of internal or terminal alkynes with methyl (acetyl~ acetonato) (triphenylphosphine) nickel (1) in either aromatic or ether solvents. In all cases vinylnickel products 2 are formed by insertion of the alkyne into the nickel=methyl bond. These complexes may be converted into a variety of organic products (e.g. alkenes, esters, vinyl halides) by treatment with appropriate reagents. Unsymmetrical alkynes give selectively the one regioisomer with the sterically largest substituent next to the nickel atom. In order to investigate the stereochemistry of the initial insertion, a x-ray diffraction study of the reaction of 1 with diphenylacetylene was carried out. This showed that the vinylnickel complex formed by overall trans insertion was the product of the reaction. Furthermore, subsequent slow isomerization of this complex, to a mixture of it and the corresponding cis isomer, demonstrated that this trans addition product is the kinetic product of the reaction. In studies with other alkynes, the product of trans addition was not always exclusively (or even predominantly) formed, but the ratio of the stereoisomers formed kinetically was substantially different from the thermodynamic ratio. Isotope labeling, added phosphine, and other experiments have allowed us to conclude that the mechanism of this reaction does involve initial cis addition. However, a coordinatively unsaturated vinylnickel complex is initially formed which can undergo rapid, phosphine-catalyzed cis-trans isomerization in competition with its conversion to the isolable phosphine-substituted kinetic reaction products. II. The reaction of CpMo(CO){sub 3}H (1a) with CpMo(CO){sub 3}R (2, R= CH{sub 3}, C{sub 2}H{sub 5}) at 50{degrees} C in THF gives the aldehyde RCHO and the dimers [CpMo(CO){sub 3}]{sub 2} (3a) and [CpMo(CO){sub 2}]{sub 2} (4a). Labeling one of the reactants with a methylcyclopentadienyl ligand it was possible to show that the

  10. A Theoretical-Experimental Study on the Structure and Activity of Certain Quinolones and the Interaction of Their Cu(II)-Complexes on a DNA Model

    PubMed Central

    Robles, J.; Martín-Polo, J.; Álvarez-Valtierra, L.; Hinojosa, L.

    2000-01-01

    Theoretical electronic Structure methods have been employed to study the structure and activity of certain (free) quinolones and the interaction of their Cu(II)-complexes on a DNA model (Rhodamine 6G (rhod)). As a manner of assessing the generated geometries, the nalidixic acid geometrical parameters obtained were tested against the crystallographic ones and it was found that the average error in the calculated geometries is small. The present study allows us to (1) Rationalize the observed differences in antibiotic activities through their electronic hardnesses. (2) Suggest a plausible mechanism of action for these drugs through formation of a reactive intermediate (or carrier) which would consist of a quinolone anion coordinated to an adequate metal center (Cu(II) in this study). (3) We find that, through this model of DNA (modeled with rhod) the interaction seems to be mediated by an effective π-π stacking. (4) Finally, an in vitro experiment was designed so that the intercalation process in DNA could be experimentally modeled as well. The quenching of the rhod fluorescence is proportional to the strength of the Cu(II)-complex-rhod interaction and therefore provides a quantitative measurement of the “intercalating” capacity of the quinolones and their copper complexes. These results agree well with the theoretical total adduct formation energies. PMID:18475962

  11. Electronic structure and vibrational spectra of cis-diammine(orotato)platinum(II), a potential cisplatin analogue: DFT and experimental study

    NASA Astrophysics Data System (ADS)

    Wysokiński, Rafał; Hernik, Katarzyna; Szostak, Roman; Michalska, Danuta

    2007-03-01

    Orotic acid (vitamin B 13) is a key intermediate in biosynthesis of the pyrimidine nucleotides in living organisms, moreover, it may serve as the biological carrier for some metal ions. cis-Diammine(orotato)platinum(II), cis-[Pt(C 5H 2N 2O 4)(NH 3) 2] can be considered as a new potential cisplatin analogue. The FT-Raman and FT-IR spectra of the title complex are reported, for the first time. The molecular structure, vibrational frequencies, and the theoretical infrared and Raman intensities have been calculated by the density functional mPW1PW91 method. The detailed vibrational assignment has been made on the basis of the calculated potential energy distribution. The theoretically predicted IR and Raman spectra show very good agreement with experiment. Natural bond orbital (NBO) analyses were performed for cisplatin, carboplatin and the title complex. The results provided new data on the nature of platinum-ligand bonding in these compounds. Strong intramolecular hydrogen bond between the orotate ligand and the coordinated ammonia group stabilizes the structure of the platinum(II) complex. Thus, it is suggested that the orotate ligand in the title complex is more inert to the substitution reactions than the chloride ligands in cisplatin.

  12. Molecular structure of mercury(II) thiocyanate complexes based on DFT calculations and experimental UV-electron spectroscopy and Raman studies

    NASA Astrophysics Data System (ADS)

    Elijošiutė, Erika; Eicher-Lorka, Olegas; Griškonis, Egidijus; Matulaitienė, Ieva; Jankūnaitė, Dalia; Denafas, Gintaras

    2013-11-01

    In this work, we report a combined experimental and theoretical study on molecular structure, vibrational and electronic spectra of [Hg(SCN)n]2-n complexes (where n = 2, 3, 4) in the aqueous solution. Molecular modeling of the mercury(II) complexes were done by the density functional theory (DFT) method using B3LYP functional with Stuttgart relativistic ECP 78MWB basis set for Hg and 6-311++G(d,p) basis set for all other atoms. The effect of different solvation models with explicit (ligand) and/or implicit water environment upon its geometry, vibrational frequencies and UV spectrum have been studied. The influence of H2O/D2O exchange on the experimental and calculated vibrational frequencies of studied complexes has been established. The double-peak character of the νHgsbnd S vibrational mode of the all analyzed mercury complexes and νCtbnd N mode of [Hg(SCN)3H2O]- complex, respectively, were proposed here for the first time. The formation of four-coordinated Hg(II) complexes with thiocyanate and (or) water ligands was verified.

  13. (meso-5,7,7,12,14,14-Hexamethyl-1,4,8,11-tetra­azacyclo­tetra­deca-4,11-diene)nickel(II) bis­[O,O′-bis(4-methyl­phen­yl) dithio­phosphate

    PubMed Central

    Xie, Bin; Xiang, Yang-Guang; Zou, Li-Ke; Chang, Xiu-Li; Ji, Chang-You

    2009-01-01

    In the title compound, [Ni(C16H32N4)](C14H14O2PS2)2 or [Ni(trans[14]dien)][S2P(OC6H4Me-4)2]2, where trans[14]dien is meso-5,7,7,12,14,14-hexa­methyl-1,4,8,11-tetra­azacyclo­tetra­deca-4,11-diene, the NiII ion lies across a centre of inversion and is four-coordinated in a relatively undistorted square-planar arrangement by the four N atoms of the macrocyclic ligand trans[14]dien. The two O,O′-di(4-methyl­phen­yl)dithio­phos­phates act as counter-ions to balance the charge. Important geometric data include Ni—N = 1.9135 (16) and 1.9364 (15) Å. PMID:21577413

  14. Experimental type II diabetes and related models of impaired glucose metabolism differentially regulate glucose transporters at the proximal tubule brush border membrane.

    PubMed

    Chichger, Havovi; Cleasby, Mark E; Srai, Surjit K; Unwin, Robert J; Debnam, Edward S; Marks, Joanne

    2016-06-01

    What is the central question of this study? Although SGLT2 inhibitors represent a promising treatment for patients suffering from diabetic nephropathy, the influence of metabolic disruption on the expression and function of glucose transporters is largely unknown. What is the main finding and its importance? In vivo models of metabolic disruption (Goto-Kakizaki type II diabetic rat and junk-food diet) demonstrate increased expression of SGLT1, SGLT2 and GLUT2 in the proximal tubule brush border. In the type II diabetic model, this is accompanied by increased SGLT- and GLUT-mediated glucose uptake. A fasted model of metabolic disruption (high-fat diet) demonstrated increased GLUT2 expression only. The differential alterations of glucose transporters in response to varying metabolic stress offer insight into the therapeutic value of inhibitors. SGLT2 inhibitors are now in clinical use to reduce hyperglycaemia in type II diabetes. However, renal glucose reabsorption across the brush border membrane (BBM) is not completely understood in diabetes. Increased consumption of a Western diet is strongly linked to type II diabetes. This study aimed to investigate the adaptations that occur in renal glucose transporters in response to experimental models of diet-induced insulin resistance. The study used Goto-Kakizaki type II diabetic rats and normal rats rendered insulin resistant using junk-food or high-fat diets. Levels of protein kinase C-βI (PKC-βI), GLUT2, SGLT1 and SGLT2 were determined by Western blotting of purified renal BBM. GLUT- and SGLT-mediated d-[(3) H]glucose uptake by BBM vesicles was measured in the presence and absence of the SGLT inhibitor phlorizin. GLUT- and SGLT-mediated glucose transport was elevated in type II diabetic rats, accompanied by increased expression of GLUT2, its upstream regulator PKC-βI and SGLT1 protein. Junk-food and high-fat diet feeding also caused higher membrane expression of GLUT2 and its upstream regulator PKC

  15. Syphilis and human experimentation from World War II to the present: a historical perspective and reflections on ethics.

    PubMed

    Cuerda-Galindo, E; Sierra-Valenti, X; González-López, E; López-Muñoz, F

    2014-11-01

    Even after the Nuremberg code was published, research on syphilis often continued to fall far short of ethical standards. We review post-World War II research on this disease, focusing on the work carried out in Guatemala and Tuskegee. Over a thousand adults were deliberately inoculated with infectious material for syphilis, chancroid, and gonorrhea between 1946 and 1948 in Guatemala, and thousands of serologies were performed in individuals belonging to indigenous populations or sheltered in orphanages. The Tuskegee syphilis study, conducted by the US Public Health Service, took place between 1932 and 1972 with the aim of following the natural history of the disease when left untreated. The subjects belonged to a rural black population and the study was not halted when effective treatment for syphilis became available in 1945. PMID:24461955

  16. Syphilis and human experimentation from World War II to the present: a historical perspective and reflections on ethics.

    PubMed

    Cuerda-Galindo, E; Sierra-Valenti, X; González-López, E; López-Muñoz, F

    2014-11-01

    Even after the Nuremberg code was published, research on syphilis often continued to fall far short of ethical standards. We review post-World War II research on this disease, focusing on the work carried out in Guatemala and Tuskegee. Over a thousand adults were deliberately inoculated with infectious material for syphilis, chancroid, and gonorrhea between 1946 and 1948 in Guatemala, and thousands of serologies were performed in individuals belonging to indigenous populations or sheltered in orphanages. The Tuskegee syphilis study, conducted by the US Public Health Service, took place between 1932 and 1972 with the aim of following the natural history of the disease when left untreated. The subjects belonged to a rural black population and the study was not halted when effective treatment for syphilis became available in 1945.

  17. Analysis of an Experimental Cortical Network: ii) Connections of Visual Areas 17 and 18 After Neonatal Injections of Ibotenic Acid

    PubMed Central

    Innocenti, G. M.; Berbel, P.

    1991-01-01

    Lesions of cortical areas 17 and 18 were produced in newborn kittens by local injections of the excitotoxin ibotenic acid. In the adult this results in a microcortex which consists of superficial layers I, II and III, in the absence of granular and infragranular layers. Horseradish peroxidase, alone or wheat germ agglutinin conjugated, was injected in the microcortex or in the contralateral, intact areas 17 and 18. The microcortex maintains several connections characteristic of normal areas 17 and 18 of the cat. It receives afferents from the dLGN, and several visual areas of the ipsilateral and contralateral hemisphere. However, it has lost its projections to dLGN, superior colliculus, and, at least in part, those to contralateral visual areas. Thus some parts of the microcortex receive from, but do not project into, the corpus callosum. In addition, the microcortex maintains afferents from ipsilateral and contralateral auditory areas AI and AII which are normally eliminated in development. PMID:1714302

  18. Impact of benznidazole on infection course in mice experimentally infected with Trypanosoma cruzi I, II, and IV.

    PubMed

    Gruendling, Ana Paula; Massago, Miyoko; Teston, Ana Paula M; Monteiro, Wuelton M; Kaneshima, Edilson N; Araújo, Silvana M; Gomes, Mônica L; Barbosa, Maria das Graças V; Toledo, Max Jean O

    2015-06-01

    American trypanosomiasis is an emerging zoonosis in the Brazilian Amazon. Studies on benznidazole (BZ) chemotherapy with Trypanosoma cruzi from this region have great relevance, given the different discrete typing units (DTUs) that infect humans in the Amazon and other regions of Brazil. We performed a parasitological, histopathological, and molecular analysis of mice inoculated with strains of T. cruzi I, II, and IV that were BZ-treated during the acute phase of infection. Groups of Swiss mice were inoculated; 13 received oral BZ, whereas the other 13 comprised the untreated controls. Unlike parasitemia, the infectivity and mortality did not vary among the DTUs. Trypanosoma cruzi DNA was detected in all tissues analyzed and the proportion of organs parasitized varied with the parasite DTU. The BZ treatment reduced the most parasitological parameters, tissue parasitism and the inflammatory processes at all infection stages and for all DTUs. However, the number of significant reductions varied according to the DTU and infection phase.

  19. Poly[di-methyl-ammonium [(μ2-benzene-1,2-di-carboxyl-ato-κ(2) O (1):O (3))[μ2-3-(pyri-din-4-yl)-1H-pyrazol-1-ido-κ(2) N (1):N (3)]cuprate(II)

    PubMed

    Na, Liu

    2013-01-01

    In the title complex, {(C2H8N)[Cu(C8H4O4)(C8H6N3)]} n , there are two Cu(II) cations (each located on a centre of inversion), one benzene-1,2-di-carboxyl-ate dianion, one 3-(pyridin-4-yl)-1H-pyrazol-1-ide anion and one di-methyl-ammonium cation in the asymmetric unit. The di-methyl-ammonium cation was highly disordered and was treated with the SQUEEZE routine in PLATON [Spek (2009 ▶). Acta Cryst. D65, 148-155]; the crystallographic data takes into account the presence of the cation. Each Cu(II) cation exhibits a square-planar coordination geometry. A benzene-1,2-di-carboxyl-ate dianion bridges two Cu(II) cations, building a linear chain along [001]. The chains are connected by 3-(pyridin-4-yl)-1H-pyrazol-1-ide anions, constructing a layer parallel to (101). The layers are assembled into a three-dimensional supra-molecular network through C-H⋯π inter-actions. PMID:24046573

  20. Biotic and abiotic mercury methylation and demethylation in sediments

    SciTech Connect

    Zhang, L.; Planas, D. )

    1994-05-01

    Inorganic mercury (Hg(II)) methylation and methylmercury (MeHg) demethylation may occur in the water column, sediment-water interface and subsurficial sediment of aquatic ecosystems. These transformations involve mainly microbial mechanisms, although abiotic methylation may play a more important role in the water compartment. The relative importance of biotic versus abiotic mechanisms of methylation has not been determined however, and abiotic demethylation remains unknown. Little quantitative information is available on the role of bacterial activity in mercury transformations. It has been reported that at least 16 genera of aerobic and anaerobic microorganisms are able to methylate HG(II), and that a greater number are able to demethylate MeHg. Nevertheless, not all populations of these species are capable of methyl- and demethyl-transformations. The actual concentration of MeHg in the aquatic environment is regulated by the relative production and decomposition rates. This, in turn, depends on the availability of Hg(II), MeHg, and bacteria as well as on the physico-chemical properties of the sample. The objective of this study was to compare mercury methylation and demethylation rates in sediment samples with and without active bacterial populations. We therefore performed experiments to follow bacterial evolution during the course of Hg(II) methylation and MeHg demethylation in sediment slurries containing both sterile and non-sterile sediments.

  1. Cobalt(II)-Based Single-Ion Magnets with Distorted Pseudotetrahedral [N2O2] Coordination: Experimental and Theoretical Investigations.

    PubMed

    Ziegenbalg, Sven; Hornig, David; Görls, Helmar; Plass, Winfried

    2016-04-18

    The synthesis and magnetic properties of cobalt(II) complexes with sterically demanding Schiff-base ligands are reported. The compounds [Co(L(Br))2] (1) and [Co(L(Ph))2]·CH2Cl2 (2·CH2Cl2) are obtained by the reaction of cobalt(II) acetate with the ligands HL(Br) and HL(Ph) in a dichloromethane/methanol mixture. 1 and 2 crystallize in the space groups P21212 and P1̅, respectively. X-ray diffraction studies revealed mononuclear constitution of both complexes. For 1, relatively short intermolecular Co-Co distances of 569 pm are observed. In compound 2, a hydrogen-bonded dichloromethane molecule is present, leading to a solvent aggregate with remarkable thermal stability for which desolvation is taking place between 150 and 210 °C. Magnetic measurements were performed to determine the zero-field-splitting (ZFS) parameter D for both complexes. Frequency-dependent susceptibility measurements revealed slow magnetic relaxation behavior with spin-reversal barriers of 36 cm(-1) for 1 and 43 cm(-1) for 2 at an applied external field of 400 Oe. This observation is related to an increasing distortion of the pseudotetrahedral coordination geometry for complex 2. These distortions can be decomposed in two major contributions. One is the elongation effect described by the parameter ϵT, which is the ratio of the averaged obtuse and acute bond angles. The other effect is related to a twisting distortion of the chelate coordination planes at the cobalt center. A comparison with literature examples reveals that the elongation effect seems to govern the overall magnetic behavior in pseudotetrahedral complexes with two bidentate chelate ligands. Ab initio calculations for complexes 1 and 2 using the CASPT2 method show strong splitting of the excited (4)T2 term, which explains the observed strong ZFS. Spin-orbit calculations with the RASSI-SO method confirm the single-molecule-magnet behavior because only small transversal elements are found for the lowest Kramers doublet for both

  2. ARSENIC (+3 OXIDATION STATE) METHYLTRANSFERASE AND THE INORGANIC ARSENIC METHYLATION PHENOTYPE

    EPA Science Inventory

    Inorganic arsenic is enzymatically methylated; hence, its ingestion results in exposure to the parent compound and various methylated arsenicals. Both experimental and epidemiological evidence suggest that some of the adverse health effects associated with chronic exposure to in...

  3. A new 3D finite element model of the IEC 60318-1 artificial ear: II. Experimental and numerical validation

    NASA Astrophysics Data System (ADS)

    Bravo, Agustín; Barham, Richard; Ruiz, Mariano; López, Juan Manuel; De Arcas, Guillermo; Alonso, Jesus

    2012-12-01

    In part I, the feasibility of using three-dimensional (3D) finite elements (FEs) to model the acoustic behaviour of the IEC 60318-1 artificial ear was studied and the numerical approach compared with classical lumped elements modelling. It was shown that by using a more complex acoustic model that took account of thermo-viscous effects, geometric shapes and dimensions, it was possible to develop a realistic model. This model then had clear advantages in comparison with the models based on equivalent circuits using lumped parameters. In fact results from FE modelling produce a better understanding about the physical phenomena produced inside ear simulator couplers, facilitating spatial and temporal visualization of the sound fields produced. The objective of this study (part II) is to extend the investigation by validating the numerical calculations against measurements on an ear simulator conforming to IEC 60318-1. For this purpose, an appropriate commercially available device is taken and a complete 3D FE model developed for it. The numerical model is based on key dimensional data obtained with a non-destructive x-ray inspection technique. Measurements of the acoustic transfer impedance have been carried out on the same device at a national measurement institute using the method embodied in IEC 60318-1. Having accounted for the actual device dimensions, the thermo-viscous effects inside narrow slots and holes and environmental conditions, the results of the numerical modelling were found to be in good agreement with the measured values.

  4. Experimental studies of hydrogen on boron nitride: II. NMR studies of orientational ordering of H{sub 2}

    SciTech Connect

    Evans, M.D.; Sullivan, N.S.

    1995-09-01

    The authors report the results of NMR studies of thin films of hydrogen adsorbed on hexagonal boron nitride. Orientational ordering is observed below 1 K but the ordering is not complete, and a clear two-component ordering is observed. Molecules are either (i) almost completely ordered with local order parameters {sigma}={l_angle}1{minus}3/2Jz{sup 2}{r_angle} clustered close to a maximum value of {sigma}{congruent}0.94 (comparable to the values for long range ordering in bulk samples at high ortho concentrations), and (ii) a large fraction of the molecules that remain nearly disordered with {sigma}{<=}0.25. The degree of orientational ordering depends on the number of hydrogen layers and on the ortho-hydrogen concentration, and these studies indicate that ordering occurs principally in the first four layers closest to the substrate, with weaker orientational ordering in the outer layers near the free surface even at temperatures as low as 210 mK.

  5. A vesiculo-bullous disease in pigs resembling foot and mouth disease. II. Experimental reproduction of the lesion.

    PubMed

    Montgomery, J F; Oliver, R E; Poole, W S; Julian, A F

    1987-03-01

    Vesiculo-bullous dermatitis of pigs characterised by presence of vesicles and bullae on the snout and feet of white skinned pigs was reproduced experimentally. Leaves of parsnips (Pastinaca sativa), or celery (Apium graveolens) infected with the fungus Sclerotinia sclerotiorum were fed or rubbed on the snouts and feet of white skinned pigs. Pigs were then exposed to sunlight or to UV light of intensity approximately 212 m W/M2 at a wavelength 340-360 nm for eight hours per day until vesicles developed. All treated pigs developed lesions on the snouts, and less frequently on the feet. Lesions were characterised by the appearance of erythema at 24 hours after treatment. Vesicles developed at 48 hours and became maximal by 72 hours. Pigs treated with plant material without exposure to UV light or exposed to UV light without contact with plant material did not develop lesions. The experimental lesions closely resemble those observed in several field cases in 1984 and 1985 in New Zealand and to lesions present in three well publicized foot and mouth disease scares at Warkworth, and Temuka in New Zealand and Legana in Tasmania.

  6. Non-standard coupled extensional and bending bias tests for planar pantographic lattices. Part II: comparison with experimental evidence

    NASA Astrophysics Data System (ADS)

    Turco, Emilio; Barcz, Katarzyna; Rizzi, Nicola Luigi

    2016-10-01

    In dell'Isola et al. (Zeitschrift für Angewandte Math und Physik 66(6):3473-3498, 2015, Proc R Soc Lond A Math Phys Eng Sci 472(2185):1-23, 2016) pantographic sheets are proposed as a basic constituent for a novel metamaterial. In Part I, see Turco et al. (Zeitschrift für Angewandte Math und Physik, doi: 10.1007/s00033-016-0713-4, 2016), two different numerical models are applied in order to design an experimental setup aimed to prove the effectiveness of introduced concept. The aim of this paper is to prove that the Hencky-type model introduced for planar pantographic sheets allows for the correct prediction, in a large range of imposed displacements, of the experimental measurements concerning specimens undergoing coupled bending and extensional deformations. The four-parameter numerical model introduced is shown to have a large range of applicability: Indeed without changing the values of the material parameters previously attributed in simple extensional tests to a specific specimen by a best-fit procedure, it is possible to forecast its behavior in all the considered type of imposed deformations. The measurements performed include the determination of reactive forces exerted by used hard devices, and the numerical modeling is able to predict very carefully quantitatively and qualitatively also this complex aspect of phenomenology, where previously attempted models seem to have failed.

  7. Evolution of heavy metal tolerance in bryophytes II. An ecological and experimental investigation of the copper moss, Scopelophila cataractae (Pottiaceae)

    SciTech Connect

    Shaw, J. )

    1987-06-01

    About six bryophyte species (including both mosses and liverworts) are generally thought to be restricted to copper-enriched substrates and are consequently known as copper mosses. One of these, Scopelophila cataractae (Pottiaceae), is known from several sites in southern Arizona and occurs at six localities in the Eastern US. Chemical analyses of substrates from the eastern US localities showed that all but one population grew on copper-enriched soil. The one substrate sample low in copper was very high in iron. Plants from five of the six eastern US localities for S. cataractae were grown experimentally on four soil types ranging from highly to not contaminated, and all grew best on the soil contaminated with copper, lead, and zinc. There was no significant variation in growth between populations on the four soil treatments. This lack of population differentiation is in contrast to flowering plants and may be related to the absence of sexual reproduction in S. cataractae in North America.

  8. Strain-hardening extrusion—II. Analysis of slip-line fields based on experimental flow patterns

    NASA Astrophysics Data System (ADS)

    Conning, S. W.; Farmer, L. E.; Oxley, P. L. B.

    1982-08-01

    A METHOD of constructing slip-line fields based on experimental extrusion flow patterns was described in a previous paper. Such fields provide a basis for constructing representative solutions of strain-hardening flow problems. In this paper, after proving some theoretical results on the structure of such solutions, a method of analyzing slip-line fields is described and some typical results presented. The analysis comprises computation of the velocity solution and construction from it of a set of streamlines for comparison with the original flow pattern; computation of the total strain by integration along the streamlines, its graduation and adjustment to meet the boundary conditions; estimation of the stress field (shear stress k and mean pressure p) and check for consistency; and computation of the forces on the boundary of the plastic region and their resultant.

  9. Long-pulse laser-induced damage in an optical anti-reflective film: II. Experimental research

    NASA Astrophysics Data System (ADS)

    Li, Changli; Ma, Yao; Wang, Di; Wang, Zhiyang; Zhang, Xihe; Liu, Haiming

    2014-12-01

    In order to verify the result of theoretical analysis about long-pulse flat-topped multi-Gaussian laser-induced damage in an optical anti-reflection film with HfO2/SiO2 composite film coating on a BK7 substrate (BK7:HfO2/SiO2), an experimental system was built, which carried out the experiment and analysis, focusing on the pulse-length 1.0 ms, flat-topped laser-induced damage. The result shows that the thermal effect is the main reason for damage under the long-pulse flat-topped laser. Moreover, the stripping and shedding occur because of the heating stress of the film happening at an early stage of the laser irradiation. However, the crack happens at laser irradiation termination. The correctness of the theoretical analysis results is verified.

  10. Background considerations for the 2H(7Be,3H)6Be experimental data II: Three-body continuum

    NASA Astrophysics Data System (ADS)

    Chae, K. Y.; Guimarães, V.

    2015-11-01

    The present article reports second background considerations for the experimentally obtained 2H(7Be,3H)6Be differential cross sections. The one-neutron transfer reaction was measured in inverse kinematics by using radioactive 7Be ( t 1/2 = 53.2 days) beams at the Holifield Radioactive Ion Beam Facility of the Oak Ridge National Laboratory in 2004 in order to search for the resonances in the unbound 6Be nucleus. Resonances in this nucleus would affect the 3He(3He,2 p)4He reaction rate of the proton-proton chain occurring in stars such as our sun. The result shows, however, that the direct transfer to 6Be resonances is not particularly strong compared to other reaction channels that can produce tritons in the exit channels. The goals of the present work is to better understand the cross section data from transfer reaction measurements by adopting background considerations using the three-body continuum.

  11. Rotational spectrum, conformation and dipole moment of 4-methyl-1,3-dioxane

    NASA Astrophysics Data System (ADS)

    Shapkin, A. A.; Galeev, R. V.; Gunderova, L. N.; Fayzullin, M. G.; Mamleev, A. H.

    2006-12-01

    The rotational spectrum of 4-methyl-1,3-dioxane, C 5H 100 II, has been recorded from 16.0 to 40.0 GHz. The a-, b- and C- type transitions with J<=57 have been observed and assigned for the normal species in the ground vibrational state. The rotational constants and the quartic centrifugal distortion constants were determined to be A = 4802.335(2) MHz, B = 2376.163(1) MHz, C = 1738.852(1) MHz and Δ J = 0.1496(6) kHz, Δ JK = 0.157(5) kHz, Δ K = 0.76(3) kHz, δJ = 0.0423(1) kHz, δK 0.260(3) kHz. Stark effect measurements were used to determine the projections of the dipole moment on the principal inertial axes (in Debye units): μ a = 0.73(1), μ b = 1.32(1), c = 1.36(1) and μ tot = 2.03(2). Comparison of the experimental rotational constants and dipole moment components with results of ab initio calculations (B3PW91/aug-cc-pVDZ) shown that 4-methyl-l,3-dioxane exist in chair form with equatorial orientation of methyl group.

  12. Effects of Technological Processes on the Tenacity and Inactivation of Norovirus Genogroup II in Experimentally Contaminated Foods▿

    PubMed Central

    Mormann, Sascha; Dabisch, Mareike; Becker, Barbara

    2010-01-01

    Contaminated food is a significant vehicle for human norovirus transmission. The present study determined the effect of physicochemical treatments on the tenacity of infective human norovirus genogroup II in selected foods. Artificially contaminated produce was subjected to a number of processes used by the food industry for preservation and by the consumer for storage and preparation. Virus recovery was carried out by using ultrafiltration and was monitored by using bacteriophage MS2 as an internal process control. Norovirus was quantified by using monoplex one-step TaqMan real-time reverse transcription (RT)-PCR and an external standard curve based on recombinant RNA standards. An RNase pretreatment step was used to avoid false-positive PCR results caused by accessible RNA, which allowed detection of intact virus particles. Significant reductions in titers were obtained with heat treatments usually applied by consumers for food preparation (baking, cooking, roasting). Generally, processes used for preservation and storage, such as cooling, freezing, acidification (≥pH 4.5), and moderate heat treatments (pasteurization), appear to be insufficient to inactivate norovirus within a food matrix or on the surface of food. Besides data for persistence in processed food, comparable data for individual matrix-specific protective effects, recovery rates, and inhibitory effects on the PCRs were obtained in this study. The established procedure might be used for other noncultivable enteric RNA viruses that are connected to food-borne diseases. The data obtained in this study may also help optimize the process for inactivation of norovirus in food by adjusting food processing technologies and may promote the development of risk assessment systems in order to improve consumer protection. PMID:19933338

  13. Ethyl pyruvate therapy attenuates experimental severe arthritis caused by type II collagen (CII) in the mouse (CIA).

    PubMed

    Di Paola, R; Mazzon, E; Galuppo, M; Esposito, E; Bramanti, P; Fink, M P; Cuzzocrea, S

    2010-01-01

    This study tested the hypothesis that ethyl pyruvate (EP), a simple aliphatic ester with anti-inflammatory effects, can reduce type II collagen-induced mouse arthritis (CIA). DBA/1J mice were used for the study, developing erosive hind paw arthritis when immunized with CII in an emulsion in complete Freund?s adjuvant (CFA). The incidence of CIA was 100 percent by day 28 in the CII-challenged mice, and the severity of CIA progressed over a 35-day period with radiographic evaluation revealing focal resorption of bone. The histopathology of CIA included erosion of the cartilage at the joint margins. EP-treatment (40 mg/kg/day i.p.) starting at the onset of arthritis (day 25) ameliorated the clinical signs at days 26-35 and improved histological status in the joint and paw. Immunohistochemical analysis for nitrotyrosine, poly (ADP-ribose) (PAR), inducible nitric oxide synthase (iNOS) revealed a positive staining in inflamed joints from mice subjected to CIA, while no staining was observed for HO-1 and Nrf-2 in the same group. The degree of staining for nitrotyrosine, PAR, iNOS, was significantly reduced in CII-challenged mice treated with the EP. Immuno-positive-staining for HO-1 and Nrf-2 was observed instead, in joints obtained from the EP-treated group. Plasma levels of TNF-α, IL-6 and the joint tissue levels of macrophage inflammatory protein (MIP)-1α and MIP-2 were also significantly reduced by EP treatment. Thirty-five days after immunization, EP-treatment significantly increased plasma levels of IL-10. These data demonstrate that EP treatment exerts an anti-inflammatory effect during chronic inflammation and is able to ameliorate the tissue damage associated with CIA.

  14. Experimental Data in Support of a Direct Displacement Mechanism for Type I/II L-Asparaginases.

    PubMed

    Schalk, Amanda M; Antansijevic, Aleksandar; Caffrey, Michael; Lavie, Arnon

    2016-03-01

    Bacterial L-asparaginases play an important role in the treatment of certain types of blood cancers. We are exploring the guinea pig L-asparaginase (gpASNase1) as a potential replacement of the immunogenic bacterial enzymes. The exact mechanism used by L-asparaginases to catalyze the hydrolysis of asparagine into aspartic acid and ammonia has been recently put into question. Earlier experimental data suggested that the reaction proceeds via a covalent intermediate using a ping-pong mechanism, whereas recent computational work advocates the direct displacement of the amine by an activated water. To shed light on this controversy, we generated gpASNase1 mutants of conserved active site residues (T19A, T116A, T19A/T116A, K188M, and Y308F) suspected to play a role in hydrolysis. Using x-ray crystallography, we determined the crystal structures of the T19A, T116A, and K188M mutants soaked in asparagine. We also characterized their steady-state kinetic properties and analyzed the conversion of asparagine to aspartate using NMR. Our structures reveal bound asparagine in the active site that has unambiguously not formed a covalent intermediate. Kinetic and NMR assays detect significant residual activity for all of the mutants. Furthermore, no burst of ammonia production was observed that would indicate covalent intermediate formation and the presence of a ping-pong mechanism. Hence, despite using a variety of techniques, we were unable to obtain experimental evidence that would support the formation of a covalent intermediate. Consequently, our observations support a direct displacement rather than a ping-pong mechanism for l-asparaginases.

  15. Experimental radiative lifetimes for highly excited states and calculated oscillator strengths for lines of astrophysical interest in singly ionized cobalt (Co II)

    NASA Astrophysics Data System (ADS)

    Quinet, P.; Fivet, V.; Palmeri, P.; Engström, L.; Hartman, H.; Lundberg, H.; Nilsson, H.

    2016-11-01

    This work reports new experimental radiative lifetimes and calculated oscillator strengths for transitions of astrophysical interest in singly ionized cobalt. More precisely, 19 radiative lifetimes in Co+ have been measured with the time-resolved laser-induced fluorescence technique using one- and two-step excitations. Out of these, seven belonging to the high lying 3d7(4F)4d configuration in the energy range 90 697-93 738 cm-1 are new, and the other 12 from the 3d7(4F)4p configuration with energies between 45 972 and 49 328 cm-1 are compared with previous measurements. In addition, a relativistic Hartree-Fock model including core-polarization effects has been employed to compute transition rates. Supported by the good agreement between theory and experiment for the lifetimes, new reliable transition probabilities and oscillator strengths have been deduced for 5080 Co II transitions in the spectral range 114-8744 nm.

  16. Circular dichroism and optical absorption spectra of mononuclear and trinuclear chiral Cu(II) amino-alcohol coordinated compounds: A combined theoretical and experimental study

    NASA Astrophysics Data System (ADS)

    Valencia, Israel; Ávila-Torres, Yenny; Barba-Behrens, Norah; Garzón, Ignacio L.

    2015-04-01

    Studies on the physicochemical properties of biomimetic compounds of multicopper oxidases are fundamental to understand their reaction mechanisms and catalytic behavior. In this work, electronic, optical, and chiroptical properties of copper(II) complexes with amino-alcohol chiral ligands are theoretically studied by means of time-dependent density functional theory. The calculated absorption and circular dichroism spectra are compared with experimental measurements of these spectra for an uncoordinated pseudoephedrine derivative, as well as for the corresponding mononuclear and trinuclear copper(II)-coordinated complexes. This comparison is useful to gain insights into their electronic structure, optical absorption and optical activity. The optical absorption and circular dichroism bands of the pseudoephedrine derivative are located in the UV-region. They are mainly due to transitions originated from n to π anti-bonding orbitals of the alcohol and amino groups, as well as from π bonding to π anti-bonding orbitals of carboxyl and phenyl groups. In the case of the mononuclear and trinuclear compounds, additional signals in the visible spectral region are present. In both systems, the origin of these bands is due to charge transfer from ligand to metal and d-d transitions.

  17. Trypanosoma cruzi DTU TcII presents higher blood parasitism than DTU TcI in an experimental model of mixed infection.

    PubMed

    Sales-Campos, Helioswilton; Kappel, Henrique Borges; Andrade, Cristiane Pontes; Lima, Tiago Pereira; de Castilho, Alessandra; Giraldo, Luis Eduardo Ramirez; Lages-Silva, Eliane

    2015-09-01

    Trypanosoma cruzi (Tc), the causative agent of Chagas disease, affects millions of people worldwide. One of the major characteristics of T. cruzi is related to its heterogeneity due to the variability of its biological properties, parasite growth rates, infectivity, tissue tropism, morbidity and virulence among different isolates observed during experimental or human infection. Moreover, presence of mixed infections in the same host in endemic areas is a matter of study due to its impact on clinical manifestations and disease progression. In this study, we evaluated the biological behavior of two Tc I strains AQ1-7 (AQ) and MUTUM (MT) and one Tc II strain (JG) during the acute phase of infection, in unique and mixed infections. A patent blood parasitism was detected only in mice inoculated with JG strain . In addition blood parasitism parameters (peak and average blood parasitism) were positively associated when JG and AQ strains were combined. In contrast, a negative association was observed in the JG+MUTUM group. The predominance of TcII strain over TcI strains was highlighted using the LSSP-PCR technique, which was performed in samples from hemoculture. Thus, this study showed important biological differences between different T. cruzi strains and discrete typing units (DTUs) in acute phase. Finally, we observed that blood parasitism during early period of infection seems to be more related to DTU than to a specific strain.

  18. Multiple sites of methylation in the methyl accepting chemotaxis proteins of Escherichia coli

    SciTech Connect

    Chelsky, D.; Dahlquist, F.W.

    1981-01-01

    The methyl-accepting chemotaxis proteins (MCP) of E coli show at least five bands when subjected to SDS-gel electrophoresis. The intensity of the individual bands varies depending on the environment of the cells before solubilization. The faster migrating bands are enhanced following attractant stimulation, whereas the slower migrating bands are enhanced following attractant dilution or repellent increase. The time scale of these intensity changes is similar to that for adaptation of the behavioral response in these cells suggesting that methylation of the MCP is involved in producing these bands. Peptide mapping experiments show three methylated peptides in both MCP I and MCP II. These results suggest multiple sites of methylation, which are responsible, at least in part, for the observed multiple bands of the MCPs.

  19. Structural, vibrational, and electronic properties of an uncoordinated pseudoephedrine derivative and its mononuclear and trinuclear copper(II)-coordinated compounds: A combined theoretical and experimental study

    NASA Astrophysics Data System (ADS)

    Valencia, Israel; Ávila-Torres, Yenny; Barba-Behrens, Norah; Garzón, Ignacio L.

    2014-11-01

    Multicopper oxidases are fundamental in a variety of biological processes in bacteria, fungi and vertebrates. The catalytic center in these enzymes is formed basically by three copper ions, bridged by oxygen bonds. In order to get insights into the reactivity of these complex systems, biomimetic compounds are usually synthesized. Accordingly, in this work, we studied structural, vibrational, and electronic properties of an uncoordinated pseudoephedrine derivative, as well as its corresponding mononuclear and trinuclear copper(II)-coordinated complexes by means of density functional theory. The calculations are compared with experimental results using measurements of the infrared spectra. It is obtained that the molecular configuration of the pseudoephedrine amino-alcohol derivative is stabilized by hydrogen bonding Osbnd H⋯N and by Csbnd H⋯π interactions that are not present in the mononuclear and trinuclear compounds. The coordination compounds show octahedral and square pyramid geometries, respectively, which are slightly distorted by Jahn-Teller effects. The analysis of their theoretical and experimental IR spectra reveals signals related with hydrogen bonding as well as metal-ligand vibrational modes. Regarding the electronic structure, the density of states was calculated in order to analyze the atomic orbital contributions present in these compounds. This analysis would provide useful insights about the optical behavior, for example, in the visible region of the spectrum of the coordinated compounds. At these energies, the optical absorption would be influenced by the orbital interaction of the Cu2+d orbitals with sp ones of the ligand, reflecting a decrease of the HOMO-LUMO gap of the organic ligand due to the presence of the copper(II) ions.

  20. DNA Methylation in Basal Metazoans: Insights from Ctenophores.

    PubMed

    Dabe, Emily C; Sanford, Rachel S; Kohn, Andrea B; Bobkova, Yelena; Moroz, Leonid L

    2015-12-01

    Epigenetic modifications control gene expression without altering the primary DNA sequence. However, little is known about DNA methylation in invertebrates and its evolution. Here, we characterize two types of genomic DNA methylation in ctenophores, 5-methyl cytosine (5-mC) and the unconventional form of methylation 6-methyl adenine (6-mA). Using both bisulfite sequencing and an ELISA-based colorimetric assay, we experimentally confirmed the presence of 5-mC DNA methylation in ctenophores. In contrast to other invertebrates studied, Mnemiopsis leidyi has lower levels of genome-wide 5-mC methylation, but higher levels of 5-mC methylation in promoters when compared with gene bodies. Phylogenetic analysis showed that ctenophores have distinct forms of DNA methyltransferase 1 (DNMT1); the zf-CXXC domain type, which localized DNMT1 to CpG sites, and is a metazoan specific innovation. We also show that ctenophores encode the full repertoire of putative enzymes for 6-mA DNA methylation, and these genes are expressed in the aboral organ of Mnemiopsis. Using an ELISA-based colorimetric assay, we experimentally confirmed the presence of 6-mA methylation in the genomes of three different species of ctenophores, M. leidyi, Beroe abyssicola, and Pleurobrachia bachei. The functional role of this novel epigenomic mark is currently unknown. In summary, despite their compact genomes, there is a wide variety of epigenomic mechanisms employed by basal metazoans that provide novel insights into the evolutionary origins of biological novelties.

  1. Carbon Monoxide (CO) Released from Tricarbonyldichlororuthenium (II) Dimer (CORM-2) in Gastroprotection against Experimental Ethanol-Induced Gastric Damage.

    PubMed

    Magierowska, Katarzyna; Magierowski, Marcin; Hubalewska-Mazgaj, Magdalena; Adamski, Juliusz; Surmiak, Marcin; Sliwowski, Zbigniew; Kwiecien, Slawomir; Brzozowski, Tomasz

    2015-01-01

    The physiological gaseous molecule, carbon monoxide (CO) becomes a subject of extensive investigation due to its vasoactive activity throughout the body but its role in gastroprotection has been little investigated. We determined the mechanism of CO released from its donor tricarbonyldichlororuthenium (II) dimer (CORM-2) in protection of gastric mucosa against 75% ethanol-induced injury. Rats were pretreated with CORM-2 30 min prior to 75% ethanol with or without 1) non-selective (indomethacin) or selective cyclooxygenase (COX)-1 (SC-560) and COX-2 (celecoxib) inhibitors, 2) nitric oxide (NO) synthase inhibitor L-NNA, 3) ODQ, a soluble guanylyl cyclase (sGC) inhibitor, hemin, a heme oxygenase (HO)-1 inductor or zinc protoporphyrin IX (ZnPPIX), an inhibitor of HO-1 activity. The CO content in gastric mucosa and carboxyhemoglobin (COHb) level in blood was analyzed by gas chromatography. The gastric mucosal mRNA expression for HO-1, COX-1, COX-2, iNOS, IL-4, IL-1β was analyzed by real-time PCR while HO-1, HO-2 and Nrf2 protein expression was determined by Western Blot. Pretreatment with CORM-2 (0.5-10 mg/kg) dose-dependently attenuated ethanol-induced lesions and raised gastric blood flow (GBF) but large dose of 100 mg/kg was ineffective. CORM-2 (5 mg/kg and 50 mg/kg i.g.) significantly increased gastric mucosal CO content and whole blood COHb level. CORM-2-induced protection was reversed by indomethacin, SC-560 and significantly attenuated by celecoxib, ODQ and L-NNA. Hemin significantly reduced ethanol damage and raised GBF while ZnPPIX which exacerbated ethanol-induced injury inhibited CORM-2- and hemin-induced gastroprotection and the accompanying rise in GBF. CORM-2 significantly increased gastric mucosal HO-1 mRNA expression and decreased mRNA expression for iNOS, IL-1β, COX-1 and COX-2 but failed to affect HO-1 and Nrf2 protein expression decreased by ethanol. We conclude that CORM-2 released CO exerts gastroprotection against ethanol-induced gastric lesions

  2. Carbon Monoxide (CO) Released from Tricarbonyldichlororuthenium (II) Dimer (CORM-2) in Gastroprotection against Experimental Ethanol-Induced Gastric Damage

    PubMed Central

    Magierowska, Katarzyna; Magierowski, Marcin; Hubalewska-Mazgaj, Magdalena; Adamski, Juliusz; Surmiak, Marcin; Sliwowski, Zbigniew; Kwiecien, Slawomir; Brzozowski, Tomasz

    2015-01-01

    The physiological gaseous molecule, carbon monoxide (CO) becomes a subject of extensive investigation due to its vasoactive activity throughout the body but its role in gastroprotection has been little investigated. We determined the mechanism of CO released from its donor tricarbonyldichlororuthenium (II) dimer (CORM-2) in protection of gastric mucosa against 75% ethanol-induced injury. Rats were pretreated with CORM-2 30 min prior to 75% ethanol with or without 1) non-selective (indomethacin) or selective cyclooxygenase (COX)-1 (SC-560) and COX-2 (celecoxib) inhibitors, 2) nitric oxide (NO) synthase inhibitor L-NNA, 3) ODQ, a soluble guanylyl cyclase (sGC) inhibitor, hemin, a heme oxygenase (HO)-1 inductor or zinc protoporphyrin IX (ZnPPIX), an inhibitor of HO-1 activity. The CO content in gastric mucosa and carboxyhemoglobin (COHb) level in blood was analyzed by gas chromatography. The gastric mucosal mRNA expression for HO-1, COX-1, COX-2, iNOS, IL-4, IL-1β was analyzed by real-time PCR while HO-1, HO-2 and Nrf2 protein expression was determined by Western Blot. Pretreatment with CORM-2 (0.5–10 mg/kg) dose-dependently attenuated ethanol-induced lesions and raised gastric blood flow (GBF) but large dose of 100 mg/kg was ineffective. CORM-2 (5 mg/kg and 50 mg/kg i.g.) significantly increased gastric mucosal CO content and whole blood COHb level. CORM-2-induced protection was reversed by indomethacin, SC-560 and significantly attenuated by celecoxib, ODQ and L-NNA. Hemin significantly reduced ethanol damage and raised GBF while ZnPPIX which exacerbated ethanol-induced injury inhibited CORM-2- and hemin-induced gastroprotection and the accompanying rise in GBF. CORM-2 significantly increased gastric mucosal HO-1 mRNA expression and decreased mRNA expression for iNOS, IL-1β, COX-1 and COX-2 but failed to affect HO-1 and Nrf2 protein expression decreased by ethanol. We conclude that CORM-2 released CO exerts gastroprotection against ethanol-induced gastric

  3. Experimental study of stable imbibition displacements in a model open fracture. II. Scale-dependent avalanche dynamics

    NASA Astrophysics Data System (ADS)

    Clotet, Xavier; Santucci, Stéphane; Ortín, Jordi

    2016-01-01

    We report the results of an experimental investigation of the spatiotemporal dynamics of stable imbibition fronts in a disordered medium, in the regime of capillary disorder, for a wide range of experimental conditions. We have used silicone oils of various viscosities μ and nearly identical oil-air surface tension, and forced them to slowly invade a model open fracture at very different flow rates v . In this second part of the study we have carried out a scale-dependent statistical analysis of the front dynamics. We have specifically analyzed the influence of μ and v on the statistical properties of the velocity Vℓ, the spatial average of the local front velocities over a window of lateral size ℓ . We have varied ℓ from the local scale defined by our spatial resolution up to the lateral system size L . Even though the imposed flow rate is constant, the signals Vℓ(t ) present very strong fluctuations which evolve systematically with the parameters μ , v , and ℓ . We have verified that the non-Gaussian fluctuations of the global velocity Vℓ(t ) are very well described by a generalized Gumbel statistics. The asymmetric shape and the exponential tail of those distributions are controlled by the number of effective degrees of freedom of the imbibition fronts, given by Neff=ℓ /ℓc (the ratio of the lateral size of the measuring window ℓ to the correlation length ℓc˜1 /√{μ v } ). The large correlated excursions of Vℓ(t ) correspond to global avalanches, which reflect extra displacements of the imbibition fronts. We show that global avalanches are power-law distributed, both in sizes and durations, with robustly defined exponents—independent of μ , v , and ℓ . Nevertheless, the exponential upper cutoffs of the distributions evolve systematically with those parameters. We have found, moreover, that maximum sizes ξS and maximum durations ξT of global avalanches are not controlled by the same mechanism. While ξS are also determined by

  4. Experimental study of stable imbibition displacements in a model open fracture. II. Scale-dependent avalanche dynamics.

    PubMed

    Clotet, Xavier; Santucci, Stéphane; Ortín, Jordi

    2016-01-01

    We report the results of an experimental investigation of the spatiotemporal dynamics of stable imbibition fronts in a disordered medium, in the regime of capillary disorder, for a wide range of experimental conditions. We have used silicone oils of various viscosities μ and nearly identical oil-air surface tension, and forced them to slowly invade a model open fracture at very different flow rates v. In this second part of the study we have carried out a scale-dependent statistical analysis of the front dynamics. We have specifically analyzed the influence of μ and v on the statistical properties of the velocity V_{ℓ}, the spatial average of the local front velocities over a window of lateral size ℓ. We have varied ℓ from the local scale defined by our spatial resolution up to the lateral system size L. Even though the imposed flow rate is constant, the signals V_{ℓ}(t) present very strong fluctuations which evolve systematically with the parameters μ, v, and ℓ. We have verified that the non-Gaussian fluctuations of the global velocity V_{ℓ}(t) are very well described by a generalized Gumbel statistics. The asymmetric shape and the exponential tail of those distributions are controlled by the number of effective degrees of freedom of the imbibition fronts, given by N_{eff}=ℓ/ℓ_{c} (the ratio of the lateral size of the measuring window ℓ to the correlation length ℓ_{c}∼1/sqrt[μv]). The large correlated excursions of V_{ℓ}(t) correspond to global avalanches, which reflect extra displacements of the imbibition fronts. We show that global avalanches are power-law distributed, both in sizes and durations, with robustly defined exponents-independent of μ, v, and ℓ. Nevertheless, the exponential upper cutoffs of the distributions evolve systematically with those parameters. We have found, moreover, that maximum sizes ξ_{S} and maximum durations ξ_{T} of global avalanches are not controlled by the same mechanism. While ξ_{S} are also

  5. Boryl-assisted hydrogenolysis of a nickel-methyl bond.

    PubMed

    Curado, Natalia; Maya, Celia; López-Serrano, Joaquín; Rodríguez, Amor

    2014-12-25

    A stable nickel(II) methyl complex containing a diphosphino-boryl (PBP) pincer ligand is described. Mechanistic studies on the hydrogenolysis of the Ni-Me bond suggest a metal ligand cooperation mechanism that involves the intermediacy of a σ-B-H Ni(0) species that further undergoes B-H oxidative addition to form a Ni(II) hydride complex.

  6. Structural damage detection based on stochastic subspace identification and statistical pattern recognition: II. Experimental validation under varying temperature

    NASA Astrophysics Data System (ADS)

    Lin, Y. Q.; Ren, W. X.; Fang, S. E.

    2011-11-01

    Although most vibration-based damage detection methods can acquire satisfactory verification on analytical or numerical structures, most of them may encounter problems when applied to real-world structures under varying environments. The damage detection methods that directly extract damage features from the periodically sampled dynamic time history response measurements are desirable but relevant research and field application verification are still lacking. In this second part of a two-part paper, the robustness and performance of the statistics-based damage index using the forward innovation model by stochastic subspace identification of a vibrating structure proposed in the first part have been investigated against two prestressed reinforced concrete (RC) beams tested in the laboratory and a full-scale RC arch bridge tested in the field under varying environments. Experimental verification is focused on temperature effects. It is demonstrated that the proposed statistics-based damage index is insensitive to temperature variations but sensitive to the structural deterioration or state alteration. This makes it possible to detect the structural damage for the real-scale structures experiencing ambient excitations and varying environmental conditions.

  7. Mechanical energy dissipation induced by sloshing and wave breaking in a fully coupled angular motion system. II. Experimental investigation

    NASA Astrophysics Data System (ADS)

    Bouscasse, B.; Colagrossi, A.; Souto-Iglesias, A.; Cercos-Pita, J. L.

    2014-03-01

    In Paper I of this series [B. Bouscasse, A. Colagrossi, A. Souto-Iglesias, and J. L. C. Pita, "Mechanical energy dissipation induced by sloshing and wave breaking in a fully coupled angular motion system. I. Theoretical formulation and numerical investigation," Phys. Fluids 26, 033103 (2014)], a theoretical and numerical model for a driven pendulum filled with liquid was developed. The system was analyzed in the framework of tuned liquid dampers and hybrid mass liquid dampers (HMLD) theory. In this paper, in order to measure the energy dissipation resulting from shallow water sloshing, an experimental investigation is conducted. Accurate evaluations of energy transfers are obtained through the recorded kinematics of the system. A set of experiments is conducted with three different liquids: water, sunflower oil, and glycerine. Coherently with the results of Paper I, the energy dissipation obtained when the tank is filled with water can mainly be explained by the breaking waves. For all three liquids, the effects of varying the external excitation amplitude are discussed.

  8. Filtering Chromatic Aberration for Wide Acceptance Angle Electrostatic Lenses II--Experimental Evaluation and Software-Based Imaging Energy Analyzer.

    PubMed

    Fazekas, Ádám; Daimon, Hiroshi; Matsuda, Hiroyuki; Tóth, László

    2016-03-01

    Here, the experimental results of the method of filtering the effect of chromatic aberration for wide acceptance angle electrostatic lens-based system are described. This method can eliminate the effect of chromatic aberration from the images of a measured spectral image sequence by determining and removing the effect of higher and lower kinetic energy electrons on each different energy image, which leads to significant improvement of image and spectral quality. The method is based on the numerical solution of a large system of linear equations and equivalent with a multivariate strongly nonlinear deconvolution method. A matrix whose elements describe the strongly nonlinear chromatic aberration-related transmission function of the lens system acts on the vector of the ordered pixels of the distortion free spectral image sequence, and produces the vector of the ordered pixels of the measured spectral image sequence. Since the method can be applied not only on 2D real- and $k$ -space diffraction images, but also along a third dimension of the image sequence that is along the optical or in the 3D parameter space, the energy axis, it functions as a software-based imaging energy analyzer (SBIEA). It can also be applied in cases of light or other type of optics for different optical aberrations and distortions. In case of electron optics, the SBIEA method makes possible the spectral imaging without the application of any other energy filter. It is notable that this method also eliminates the disturbing background significantly in the present investigated case of reflection electron energy loss spectra. It eliminates the instrumental effects and makes possible to measure the real physical processes better. PMID:26863662

  9. Micromorphological Aspects of Forensic Geopedology II: Ultramicroscopic vs Microscopic Characterization of Phosphatic Impregnations on Soil Particles in Experimental Burials

    NASA Astrophysics Data System (ADS)

    Ern, S. I. E.; Trombino, L.; Cattaneo, C.

    2012-04-01

    Grows up the importance of the role played by soil scientists in the modern forensic sciences, in particular when buried human remains strongly decomposed or skeletonized are found in different environment situations. Among the different techniques normally used in geopedology, it is usefull to apply in such forensic cases, soil micromorphology (including optical microscopy and ultramicroscopy) that has been underused up today, for various kind of reasons. An interdisciplinary Italian-team, formed by earth scientists and legal medicine, is working on several sets of experimental burial of pigs and piglets in different soil types and for different times of burial, in order to get new evidences on environmental behaviour related to the burial, focalising on geopedological and micropedological aspects. The present work is focused on: - ultramicroscopic (SEM-EDS) characterization of the phosphatic impregnation (by body fluids) on soils sampled under the dead bodies of five couples of pigs, buried respectively for one month, six month, one year, two years and two years and half in two different areas; - microscopic (petrographic microscope) and ultramicroscopic (SEM-EDS) cross characterization of the phosphatic impregnation (by body fluids) on soils sampled under the dead bodies of several piglets, buried for twenty months. The first results show trends of persistency of such phosphatic features, mainly related to the grain size of the impregnated soil particles and weather conditions (or seasons) of exhumation, while apparently time since burial is only marginally effective for the investigated burial period. Further experiments are in progress in order to clarify the pathways of phosphorus precipitation and leaching for longer times of burial and different seasons of exhumation, both from the microscopic and the pedological/chemical point of view.

  10. Crystal structure of aqua­{μ-N-[3-(di­methyl­amino)­prop­yl]-N′-2-(oxidophen­yl)oxamidato}(1,10-phen­anthroline-5,6-dione)dicopper(II) perchlorate hemihydrate

    PubMed Central

    Zhang, Xin; Li, Yan-Tuan; Wu, Zhi-Yong

    2015-01-01

    The title compound, [Cu2(C13H16N3O3)(C12H6N2O2)(H2O)]ClO4·0.5H2O, consists of a cis-oxamide-bridged binuclear CuII complex cation, a perchlorate anion and half a solvent water mol­ecule. One CuII cation is N,N′,N",O-chelated by an N-[3-(di­methyl­amino)­prop­yl]-N′-(2-hy­droxy­phen­yl)oxamide trianion in a distorted square-planar geometry, whereas the other CuII cation is O,O′-chelated by the oxamide moiety of the anion and N,N′-chelated by a 1,10-phenanthroline-5,6-dione mol­ecule, and a water mol­ecule further coordinates the second CuII cation, completing a distorted square-pyramidal coordination geometry. In the crystal, classical O—H⋯O hydrogen bonds, weak C—H⋯O hydrogen-bonding inter­actions and π–π stacking inter­actions link the complex cations, anions and solvent water mol­ecules into a three-dimensional supra­molecular architecture. In the crystal, the di­methyl­amino­propyl unit of the oxamide anion is disordered over two positions with an occupancy ratio of 0.561 (11):0.439 (11); the solvent water mol­ecule is also disordered over two positions, the occupancy ratio being 0.207 (10):0.293 (10). PMID:26090146

  11. Aryltriazole C-nucleosides with affinity to certain DNA sequence. II. Synthesis of 4-(beta-D-erythrofuranosyl)-2-(4-methyl-3-nitrophenyl)-1,2,3-triazole from D-psicose.

    PubMed

    Dabrowska, M; Krajewska, D; Rózański, A

    2001-01-01

    The paper describes the synthesis of 4-(beta-D-erythrofuranosyl)-2-(4-methyl-3-nitrophenyl)-1,2,3-triazole. This compound is a starting material for synthesis of C-nucleosides, having a potential affinity with G-C base pair.

  12. Combined theoretical and experimental studies on the molecular structure, spectral and Hirshfeld surface studies of NLO tris(thiourea)zinc(II) sulfate crystals

    NASA Astrophysics Data System (ADS)

    Muthu, K.; Meenatchi, V.; Rajasekar, M.; Aditya Prasad, A.; Meena, K.; Agilandeshwari, R.; Kanagarajan, V.; Meenakshisundaram, SP.

    2015-07-01

    Transparent single crystals of tris(thiourea)zinc(II) sulfate (ZTS) were grown by slow evaporation technique at room temperature from an aqueous solution containing zinc sulfate and thiourea in the molar ratio 1:3. The experimental and theoretical studies on the molecular structure and vibrational spectra of ZTS were investigated by single crystal X-ray diffraction, FT-IR and density functional theory (DFT). The recorded X-ray diffraction bond parameters are compared with theoretical values calculated at B3LYP/LANL2DZ level. The observed vibrational patterns were compared with the computed wave numbers. The energy and oscillator strength calculated by TD-DFT results complement with the experimental findings. The first-order molecular hyperpolarizability, polarizability, dipole moment and HOMO-LUMO band gap energies were derived. The molecular stability and bond strength were investigated by applying the natural bond orbital analysis (NBO). Information about the size, shape, charge density distribution and site of chemical reactivity of the molecule has been obtained by mapping electron density with molecular electrostatic potential (MEP) using the same level of basis set. Intermolecular hydrogen bonding was investigated by means of the Hirshfeld surfaces, and the role of the Nsbnd H⋯O interactions as driving force for crystal structure formation has been demonstrated. The percentages of hydrogen bonding interactions are analyzed by Fingerprint plots of Hirshfeld surface.

  13. Experimental characterization and macro-modeling of mechanical strength of multi-sheets and multi-materials spot welds under pure and mixed modes I and II

    NASA Astrophysics Data System (ADS)

    Chtourou, Rim; Haugou, Gregory; Leconte, Nicolas; Zouari, Bassem; Chaari, Fahmi; Markiewicz, Eric

    2015-09-01

    Resistance Spot Welding (RSW) of multiple sheets with multiple materials are increasingly realized in the automotive industry. The mechanical strength of such new generation of spot welded assemblies is not that much dealt with. This is true in particular for experiments dedicated to investigate the mechanical strength of spot weld made by multi sheets of different grades, and their macro modeling in structural computations. Indeed, the most published studies are limited to two sheet assemblies. Therefore, in the first part of this work an advanced experimental set-up with a reduced mass is proposed to characterize the quasi-static and dynamic mechanical behavior and rupture of spot weld made by several sheets of different grades. The proposed device is based on Arcan test, the plates contribution in the global response is, thus, reduced. Loading modes I/II are, therefore, combined and well controlled. In the second part a simplified spot weld connector element (macroscopic modeling) is proposed to describe the nonlinear response and rupture of this new generation of spot welded assemblies. The weld connector model involves several parameters to be set. The remaining parameters are finally identified through a reverse engineering approach using mechanical responses of experimental tests presented in the first part of this work.

  14. Advances in light-induced polymerizations: I. Shadow cure in free radical photopolymerizations II. Experimental and modeling studies of photoinitiator systems for effective polymerizations with LEDs

    NASA Astrophysics Data System (ADS)

    Kitano, Hajime

    Photopolymerization has become the standard for many coating and printing applications that require rapid curing at room temperature due to its potential to reduce volatile organic compound (VOC) emissions while providing a means for efficient manufacturing processes. These advantages could be useful in a variety of emerging applications, such as anisotropic conductive films (ACF) if photopolymerization could extend into relatively narrow shadow regions which are not directly illuminated, and if visible wavelengths that are not absorbed by polyimide films could be used to trigger the reaction. The broad objectives of this research are i) to examine the factors that determine the attainable extent of shadow cure in free radical polymerizations, and ii) to develop initiator systems effective for polymerization using visible light and light emitting diode (LED) lamps. Project I: Shadow Cure in Free Radical Photopolymerizations. In this project, the extent of shadow cure in visible-light-induced free radical photopolymerization is investigated. A number of effective methods such as adding additives, utilizing a reflective stage, and increasing the light intensity are introduced. In addition, the use of fluorescent dyes in multi-component photoinitiator systems proved to be very effective for shadow cure because the fluorescent light emitted from the dye could irradiate the shadow region. When considering practical resins, mixtures of oligomers and monomers, the viscosity is the major barrier that must be overcome in order to achieve high conversion in the shadow regions using visible-light-induced multi-component photoinitiator systems. Hence, instead of using multi-component systems, a commercial visible-light-induced single-component photoinitiator is investigated. As a result, a high conversion in shadow regions of the viscous oligomer containing resin is achieved. Project II: Experimental and Modeling Studies of Photoinitiator Systems for Effective Polymerizations

  15. An atlas of DNA methylation in diverse bovine tissues

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We launched an effort to produce a reference cattle DNA methylation resource to improve animal production. We will employ experimental pipelines built around next generation sequencing technologies to map DNA methylation in cultured cells and primary tissues systems frequently involved in animal pro...

  16. Doppler-broadened NICE-OHMS beyond the cavity-limited weak absorption condition - II: Experimental verification

    NASA Astrophysics Data System (ADS)

    Hausmaninger, Thomas; Silander, Isak; Ma, Weiguang; Axner, Ove

    2016-01-01

    Doppler-broadened (Db) noise-immune cavity-enhanced optical heterodyne molecular spectrometry (NICE-OHMS) is normally described by an expression, here termed the conventional (CONV) description, that is restricted to the conventional cavity-limited weak absorption condition (CCLWA), i.e. when the single pass absorbance is significantly smaller than the empty cavity losses, i.e. when α0 L < < π / F. To describe NICE-OHMS signals beyond this limit two simplified extended descriptions (termed the extended locking and extended transmission description, ELET, and the extended locking and full transmission description, ELFT), which are assumed to be valid under the relaxed cavity-limited weak absorption condition (RCLWA), i.e. when α0 L < π / F, and a full description (denoted FULL), presumed to be valid also when the α0 L < π / F condition does not hold, have recently been derived in an accompanying work (Ma W, et al. Doppler-broadened NICE-OHMS beyond the cavity-limited weak absorption condition - I. Theoretical Description. J Quant Spectrosc Radiat Transfer, 2015, http://dx.doi.org/10.1016/j.jqsrt.2015.09.007). The present work constitutes an experimental verification and assessment of the validity of these, performed in the Doppler limit for a set of Fα0 L / π values (up to 3.5); it is shown under which conditions the various descriptions are valid. It is concluded that for samples with Fα0 L / π up to 0.01, all descriptions replicate the data well. It is shown that the CONV description is adequate and provides accurate assessments of the signal strength (and thereby the analyte concentration) up to Fα0 L / π of around 0.1, while the ELET is accurate for Fα0 L / π up to around 0.3. The ELFT description mimics the Db NICE-OHMS signal well for Fα0 L / π up to around unity, while the FULL description is adequate for all Fα0 L / π values investigated. Access to these descriptions both increases considerably the dynamic range of the technique and

  17. DNA methylation in plants.

    PubMed

    Vanyushin, B F

    2006-01-01

    DNA in plants is highly methylated, containing 5-methylcytosine (m5C) and N6-methyladenine (m6A); m5C is located mainly in symmetrical CG and CNG sequences but it may occur also in other non-symmetrical contexts. m6A but not m5C was found in plant mitochondrial DNA. DNA methylation in plants is species-, tissue-, organelle- and age-specific. It is controlled by phytohormones and changes on seed germination, flowering and under the influence of various pathogens (viral, bacterial, fungal). DNA methylation controls plant growth and development, with particular involvement in regulation of gene expression and DNA replication. DNA replication is accompanied by the appearance of under-methylated, newly formed DNA strands including Okazaki fragments; asymmetry of strand DNA methylation disappears until the end of the cell cycle. A model for regulation of DNA replication by methylation is suggested. Cytosine DNA methylation in plants is more rich and diverse compared with animals. It is carried out by the families of specific enzymes that belong to at least three classes of DNA methyltransferases. Open reading frames (ORF) for adenine DNA methyltransferases are found in plant and animal genomes, and a first eukaryotic (plant) adenine DNA methyltransferase (wadmtase) is described; the enzyme seems to be involved in regulation of the mitochondria replication. Like in animals, DNA methylation in plants is closely associated with histone modifications and it affects binding of specific proteins to DNA and formation of respective transcription complexes in chromatin. The same gene (DRM2) in Arabidopsis thaliana is methylated both at cytosine and adenine residues; thus, at least two different, and probably interdependent, systems of DNA modification are present in plants. Plants seem to have a restriction-modification (R-M) system. RNA-directed DNA methylation has been observed in plants; it involves de novo methylation of almost all cytosine residues in a region of si

  18. Ab initio structural modeling of and experimental validation for Chlamydia trachomatis protein CT296 reveal structural similarity to Fe(II) 2-oxoglutarate-dependent enzymes

    SciTech Connect

    Kemege, Kyle E.; Hickey, John M.; Lovell, Scott; Battaile, Kevin P.; Zhang, Yang; Hefty, P. Scott

    2012-02-13

    Chlamydia trachomatis is a medically important pathogen that encodes a relatively high percentage of proteins with unknown function. The three-dimensional structure of a protein can be very informative regarding the protein's functional characteristics; however, determining protein structures experimentally can be very challenging. Computational methods that model protein structures with sufficient accuracy to facilitate functional studies have had notable successes. To evaluate the accuracy and potential impact of computational protein structure modeling of hypothetical proteins encoded by Chlamydia, a successful computational method termed I-TASSER was utilized to model the three-dimensional structure of a hypothetical protein encoded by open reading frame (ORF) CT296. CT296 has been reported to exhibit functional properties of a divalent cation transcription repressor (DcrA), with similarity to the Escherichia coli iron-responsive transcriptional repressor, Fur. Unexpectedly, the I-TASSER model of CT296 exhibited no structural similarity to any DNA-interacting proteins or motifs. To validate the I-TASSER-generated model, the structure of CT296 was solved experimentally using X-ray crystallography. Impressively, the ab initio I-TASSER-generated model closely matched (2.72-{angstrom} C{alpha} root mean square deviation [RMSD]) the high-resolution (1.8-{angstrom}) crystal structure of CT296. Modeled and experimentally determined structures of CT296 share structural characteristics of non-heme Fe(II) 2-oxoglutarate-dependent enzymes, although key enzymatic residues are not conserved, suggesting a unique biochemical process is likely associated with CT296 function. Additionally, functional analyses did not support prior reports that CT296 has properties shared with divalent cation repressors such as Fur.

  19. Ab Initio Structural Modeling of and Experimental Validation for Chlamydia trachomatis Protein CT296 Reveal Structural Similarity to Fe(II) 2-Oxoglutarate-Dependent Enzymes▿

    PubMed Central

    Kemege, Kyle E.; Hickey, John M.; Lovell, Scott; Battaile, Kevin P.; Zhang, Yang; Hefty, P. Scott

    2011-01-01

    Chlamydia trachomatis is a medically important pathogen that encodes a relatively high percentage of proteins with unknown function. The three-dimensional structure of a protein can be very informative regarding the protein's functional characteristics; however, determining protein structures experimentally can be very challenging. Computational methods that model protein structures with sufficient accuracy to facilitate functional studies have had notable successes. To evaluate the accuracy and potential impact of computational protein structure modeling of hypothetical proteins encoded by Chlamydia, a successful computational method termed I-TASSER was utilized to model the three-dimensional structure of a hypothetical protein encoded by open reading frame (ORF) CT296. CT296 has been reported to exhibit functional properties of a divalent cation transcription repressor (DcrA), with similarity to the Escherichia coli iron-responsive transcriptional repressor, Fur. Unexpectedly, the I-TASSER model of CT296 exhibited no structural similarity to any DNA-interacting proteins or motifs. To validate the I-TASSER-generated model, the structure of CT296 was solved experimentally using X-ray crystallography. Impressively, the ab initio I-TASSER-generated model closely matched (2.72-Å Cα root mean square deviation [RMSD]) the high-resolution (1.8-Å) crystal structure of CT296. Modeled and experimentally determined structures of CT296 share structural characteristics of non-heme Fe(II) 2-oxoglutarate-dependent enzymes, although key enzymatic residues are not conserved, suggesting a unique biochemical process is likely associated with CT296 function. Additionally, functional analyses did not support prior reports that CT296 has properties shared with divalent cation repressors such as Fur. PMID:21965559

  20. Statistical model based iterative reconstruction (MBIR) in clinical CT systems. Part II. Experimental assessment of spatial resolution performance

    SciTech Connect

    Li, Ke; Chen, Guang-Hong; Garrett, John; Ge, Yongshuai

    2014-07-15

    Purpose: Statistical model based iterative reconstruction (MBIR) methods have been introduced to clinical CT systems and are being used in some clinical diagnostic applications. The purpose of this paper is to experimentally assess the unique spatial resolution characteristics of this nonlinear reconstruction method and identify its potential impact on the detectabilities and the associated radiation dose levels for specific imaging tasks. Methods: The thoracic section of a pediatric phantom was repeatedly scanned 50 or 100 times using a 64-slice clinical CT scanner at four different dose levels [CTDI{sub vol} =4, 8, 12, 16 (mGy)]. Both filtered backprojection (FBP) and MBIR (Veo{sup ®}, GE Healthcare, Waukesha, WI) were used for image reconstruction and results were compared with one another. Eight test objects in the phantom with contrast levels ranging from 13 to 1710 HU were used to assess spatial resolution. The axial spatial resolution was quantified with the point spread function (PSF), while the z resolution was quantified with the slice sensitivity profile. Both were measured locally on the test objects and in the image domain. The dependence of spatial resolution on contrast and dose levels was studied. The study also features a systematic investigation of the potential trade-off between spatial resolution and locally defined noise and their joint impact on the overall image quality, which was quantified by the image domain-based channelized Hotelling observer (CHO) detectability index d′. Results: (1) The axial spatial resolution of MBIR depends on both radiation dose level and image contrast level, whereas it is supposedly independent of these two factors in FBP. The axial spatial resolution of MBIR always improved with an increasing radiation dose level and/or contrast level. (2) The axial spatial resolution of MBIR became equivalent to that of FBP at some transitional contrast level, above which MBIR demonstrated superior spatial resolution than

  1. Methylation and Release of Mercury From the Solid Phase. What Comes First?

    NASA Astrophysics Data System (ADS)

    Regnell, O.

    2004-05-01

    It is a well-known fact that methylation leads to a dramatic increase in the bioavailability of mercury (Hg). All recent observations support the notion that Hg methylation is almost exclusively an anaerobic process. According to the reigning paradigm, methylation of Hg takes place in the cytoplasm of anaerobic bacteria, notably sulfate-reducing bacteria. It is believed that certain forms of inorganic divalent Hg (Hg(II)), can readily diffuse across the cell membrane. In addition, a recent study suggested that active uptake may occur when Hg is bound to low weight organic molecules. In the cytoplasm, cobalamin-dependent biochemical pathways, designed to methylate substrates other than Hg(II), are held responsible for the methylation of Hg(II). However, recent results from studies in a Swedish wetland (within the project "Svartsjoprojektet", aiming at understanding Hg dynamics in a Hg-polluted river-lake system) have led us to question whether Hg methylation does occur exclusively within cells. A provocative interpretation of our results is that methylation preceded the release of Hg from the solid phase, e.g. that Hg(II) sorbed to solid surfaces was methylated and subsequently released as methyl Hg to the sulfidic water. I will discuss this possibility in light of existing evidence that Hg methylation is an intra cellular process.

  2. Covering your bases: inheritance of DNA methylation in plant genomes.

    PubMed

    Niederhuth, Chad E; Schmitz, Robert J

    2014-03-01

    Cytosine methylation is an important base modification that is inherited across mitotic and meiotic cell divisions in plant genomes. Heritable methylation variants can contribute to within-species phenotypic variation. Few methylation variants were known until recently, making it possible to begin to address major unanswered questions: the extent of natural methylation variation within plant genomes, its effects on phenotypic variation, its degree of dependence on genotype, and how it fits into an evolutionary context. Techniques like whole-genome bisulfite sequencing (WGBS) make it possible to determine cytosine methylation states at single-base resolution across entire genomes and populations. Application of this method to natural and novel experimental populations is revealing answers to these long-standing questions about the role of DNA methylation in plant genomes.

  3. Genome-wide quantitative assessment of variation in DNA methylation patterns

    PubMed Central

    Xie, Hehuang; Wang, Min; de Andrade, Alexandre; de F. Bonaldo, Maria; Galat, Vasil; Arndt, Kelly; Rajaram, Veena; Goldman, Stewart; Tomita, Tadanori; Soares, Marcelo B.

    2011-01-01

    Genomic DNA methylation contributes substantively to transcriptional regulations that underlie mammalian development and cellular differentiation. Much effort has been made to decipher the molecular mechanisms governing the establishment and maintenance of DNA methylation patterns. However, little is known about genome-wide variation of DNA methylation patterns. In this study, we introduced the concept of methylation entropy, a measure of the randomness of DNA methylation patterns in a cell population, and exploited it to assess the variability in DNA methylation patterns of Alu repeats and promoters. A few interesting observations were made: (i) within a cell population, methylation entropy varies among genomic loci; (ii) among cell populations, the methylation entropies of most genomic loci remain constant; (iii) compared to normal tissue controls, some tumors exhibit greater methylation entropies; (iv) Alu elements with high methylation entropy are associated with high GC content but depletion of CpG dinucleotides and (v) Alu elements in the intronic regions or far from CpG islands are associated with low methylation entropy. We further identified 12 putative allelic-specific methylated genomic loci, including four Alu elements and eight promoters. Lastly, using subcloned normal fibroblast cells, we demonstrated the highly variable methylation patterns are resulted from low fidelity of DNA methylation inheritance. PMID:21278160

  4. Methyl salicylate overdose

    MedlinePlus

    Deep heating rubs overdose; Oil of wintergreen overdose ... These products contain methyl salicylate: Deep-heating creams used to relieve sore muscles and joints (Ben Gay, Icy Hot) Oil of wintergreen Solutions for vaporizers Other products may also ...

  5. Experimental evidence for chair-like transition states in aldol reactions of methyl ketone lithium enolates: stereoselective synthesis and utilization of a deuterium-labeled enolate as a probe of reaction stereochemistry.

    PubMed

    Liu, Christopher M; Smith, William J; Gustin, Darin J; Roush, William R

    2005-04-27

    Aldol reactions of methyl ketone lithium enolates proceed via chairlike Zimmerman-Traxler transition states with 7:1 to 50:1 preference over alternative, boatlike transition structures, as determined by studies involving the configurationally stable deuterium-labeled enol silane 18 as the lithium enolate precursor.

  6. Progression of Prostate Carcinogenesis and Dietary Methyl Donors: Temporal Dependence

    PubMed Central

    Shabbeer, Shabana; Williams, Simon A.; Simons, Brian W.; Herman, James G.; Carducci, Michael A.

    2011-01-01

    Insufficient dose of dietary methyl groups are associated with a host of conditions ranging from neural tube defects to cancer. On the other hand, it is not certain what effect excess dietary methyl groups could have on cancer. This is especially true for prostate cancer (PCa), a disease that is characterized by increasing DNA methylation changes with increasing grade of the cancer. In this three-part study in animals, we look at (i) the effect of excess methyl donors on the growth rate of PCa in vivo, (ii) the ability of 5-aza-2'-deoxycytidine, a demethylating agent, to demethylate in the presence of excess dietary methyl donors and (iii) the effect of in utero feeding of excess methyl donors to the later onset of PCa. The results show that when mice are fed a dietary excess of methyl donors, we do not see (i) an increase in the growth rate of DU-145 and PC-3 xenografts in vivo, or (ii) interference in the ability of 5-aza-2'-deoxycytidine to demethylate the promoters of Androgen Receptor or Reprimo of PCa xenografts but (iii) a protective effect on the development of higher grades of PCa in the “Hi-myc” mouse model of PCa which were fed the increased methyl donors in utero. We conclude that the impact of dietary methyl donors on PCa progression depends upon the timing of exposure to the dietary agents. When fed before the onset of cancer, i.e. in utero, excess methyl donors can have a protective effect on the progression of cancer. PMID:22139053

  7. Analysis of DNA Methylation in Various Swine Tissues

    PubMed Central

    Niu, Weiping; Yang, Runjun; Zhang, Yonghong; Qiu, Zhengyan; Sun, Boxing; Zhao, Zhihui

    2011-01-01

    DNA methylation is known to play an important role in regulating gene expression during biological development and tissue differentiation in eukaryotes. In this study, we used the fluorescence-labeled methylation-sensitive amplified polymorphism (F-MSAP) method to assess the extent and pattern of cytosine methylation in muscle, heart, liver, spleen, lung, kidney and stomach from the swine strain Laiwu, and we also examined specific methylation patterns in the seven tissues. In total, 96,371 fragments, each representing a recognition site cleaved by either or both EcoRI + HpaII and EcoRI + MspI, the HpaII and MspI are isoschizomeric enzymes, were amplified using 16 pairs of selective primers. A total of 50,094 sites were found to be methylated at cytosines in seven tissues. The incidence of DNA methylation was approximately 53.99% in muscle, 51.24% in the heart, 50.18% in the liver, 53.31% in the spleen, 51.97% in the lung, 51.15% in the kidney and 53.39% in the stomach, as revealed by the incidence of differential digestion. Additionally, differences in DNA methylation levels imply that such variations may be related to specific gene expression during tissue differentiation, growth and development. Three types of bands were generated in the F-MSAP profile, the total numbers of these three types of bands in the seven tissues were 46,277, 24,801 and 25,293, respectively. In addition, different methylation patterns were observed in seven tissues from pig, and almost all of the methylation patterns detected by F-MSAP could be confirmed by Southern analysis using the isolated amplified fragments as probes. The results clearly demonstrated that the F-MSAP technique can be adapted for use in large-scale DNA methylation detection in the pig genome. PMID:21283691

  8. The TcI and TcII Trypanosoma cruzi experimental infections induce distinct immune responses and cardiac fibrosis in dogs

    PubMed Central

    Duz, Ana Luiza Cassin; Vieira, Paula Melo de Abreu; Roatt, Bruno Mendes; Aguiar-Soares, Rodrigo Dian Oliveira; Cardoso, Jamille Mirelle de Oliveira; de Oliveira, Flávia Carvalho Bitencourt; Reis, Levi Eduardo Soares; Tafuri, Washington Luiz; Veloso, Vanja Maria; Reis, Alexandre Barbosa; Carneiro, Cláudia Martins

    2014-01-01

    Trypanosoma cruzi infection may be caused by different strains with distinct discrete typing units (DTUs) that can result in variable clinical forms of chronic Chagas disease. The present study evaluates the immune response and cardiac lesions in dogs experimentally infected with different T. cruzi strains with distinct DTUs, namely, the Colombian (Col) and Y strains of TcI and TcII DTU, respectively. During infection with the Col strain, increased levels of alanine aminotransferase, erythrocytes, haematocrit and haemoglobin were observed. In addition, CD8+ T-lymphocytes isolated from the peripheral blood produced higher levels of interleukin (IL)-4. The latter suggests that during the acute phase, infection with the Col strain may remain unnoticed by circulating mononuclear cells. In the chronic phase, a significant increase in the number of inflammatory cells was detected in the right atrium. Conversely, infection with the Y strain led to leucopoenia, thrombopoenia, inversion of the ratio of CD4+/CD8+ T-lymphocytes and alterations in monocyte number. The Y strain stimulated the production of interferon-γ by CD4+ and CD8+ T-lymphocytes and IL-4 by CD8+ T-cells. In the chronic phase, significant heart inflammation and fibrosis were observed, demonstrating that strains of different DTUs interact differently with the host. PMID:25591108

  9. Electrorefining of copper from a cuprous ion complexing electrolyte. II. Experimental comparison of possible alternative electrolytes and preliminary cost engineering analysis

    SciTech Connect

    Brown, A.P.; Loutfy, R.O.; Cook, G.M.

    1980-04-01

    The energy saving potential and refining capability of three copper(I)/electrolyte systems for the electrorefining of copper were compared experimentally. The alternative electrolyte systems studied were copper(I)/acid chloride, copper(I)/acetonitrile and sulfuric acid, and copper(I)/ammonia solutions. These were compared to the conventional copper(II)/sulfuric acid electrolyte. All of the alternative electrolyte systems demonstrated at least some potential for saving energy when run at an equal deposition rate to the conventional process; the chloride electrolyte showed the greatest energy saving potential, about 70%, and the ammonia electrolyte showed the least, about 25%. All of the alternative electrolyte systems, however, exhibited performance problems, primarily with regard to inadequate separation of impurities. A preliminary capital cost estimate was made for the copper(I)/chloride system. This estimate showed that, for the alternative electrolyte system to be cost competitive (that is, a reduction of capital cost of about 15 to 20%) with the conventional electrorefining process, the refining cells would have to be operated at a current density of about 25 to 30 mA-cm/sup -2/. At this current density, the estimated energy saving potential for the copper(I)/chloride system was still about 50%.

  10. Column solid phase extraction and flame atomic absorption spectrometric determination of manganese(II) and iron(III) ions in water, food and biological samples using 3-(1-methyl-1H-pyrrol-2-yl)-1H-pyrazole-5-carboxylic acid on synthesized graphene oxide.

    PubMed

    Pourjavid, Mohammad Reza; Sehat, Ali Akbari; Arabieh, Masoud; Yousefi, Seyed Reza; Hosseini, Majid Haji; Rezaee, Mohammad

    2014-02-01

    A modified, selective, highly sensitive and accurate procedure for the determination of trace amounts of manganese and iron ions is established in the presented work. 3-(1-Methyl-1H-pyrrol-2-yl)-1H-pyrazole-5-carboxylic acid (MPPC) and graphene oxide (GO) were used in a glass column as chelating reagent and as adsorbent respectively prior to their determination by flame atomic absorption spectrometry. The adsorption mechanism of titled metals complexes on GO was investigated by using computational chemistry approach based on PM6 semi-empirical potential energy surface (PES). The effect of some parameters including pH, flow rate and volume of sample and type, volume and concentration of eluent, as well as the adsorption capacity of matrix ions on the recovery of Mn(II) and Fe(III) was investigated. The limit of detection was 145 and 162 ng L(-1) for Mn(II) and Fe(III), respectively. Calibration was linear over the range of 0.31-355 μg L(-1) for Mn(II) and 0.34-380 μg L(-1) for Fe(III) ions. The method was successfully applied for the determination of understudied ions in water, food and biological samples.

  11. Crystal structure of poly[(4-amino­pyridine-κN)(N,N-di­methyl­formamide-κO)(μ3-pyridine-3,5-di­carboxyl­ato-κ3 N:O 3:O 5)copper(II)

    PubMed Central

    Shen, Cheng-Chen; Hua, Xiu-Ni; Han, Lei

    2016-01-01

    The title compound, [Cu(C7H3NO4)(C5H6N2)(C3H7NO]n, is an amino-function­alized chiral metal–organic framework with (10,3)-a topology. It has been constructed via the assembly of the achiral triconnected pyridine-3,5-di­carboxyl­ate (3,5-PDC) building block and a triconnected CuII atom. Each CuII ion is coordinated by two O atoms and one N atom, respectively, of three crystallographically independent 3,5-PDC ligands. The square-pyramidal (CuN2O3) coordination geometry of the CuII ion is completed by an N atom of a terminal 4-amino­pyridine (4-APY) ligand and the O atom of a terminal N,N-di­methyl­formamide (DMF) ligand to give a triconnected ‘T’-shaped secondary building unit, which becomes trigonal in the resulting (10,3)-a topology. In the three-dimensional structure, weak N—H⋯O hydrogen bonds are observed in which the donor N—H groups are provided by the 4-APY ligands and the acceptor O atoms are provided by the non-coordinating carboxylate O atoms of the 3,5-PDC ligands. PMID:27375859

  12. Bis(1-methyl-1H-imidazole-κN 3)[N,N′-o-phenyl­enebis(pyridine-2-carbox­amido)-κ4 N]manganese(II)

    PubMed Central

    Zahran, Zaki N.; Xu, Nan; Powell, Douglas R.; Richter-Addo, George B.

    2009-01-01

    The title compound, [Mn(C18H12N4O2)(C4H6N2)2], belongs to the family of 1,2-bis­(pyridine-2-carboxamido)benzene (H2bpb) ligated metal complexes. The manganese center is octa­hedrally coordinated by a bpb ligand and two axial 1-methyl­imidazole mol­ecules. The axial N—Mn—N group is bent with a bond angle of 151.79 (7)°. PMID:21581541

  13. Pyroprocessing of oxidized sodium-bonded fast reactor fuel - An experimental study of treatment options for degraded EBR-II fuel

    SciTech Connect

    Hermann, S.D.; Gese, N.J.; Wurth, L.A.

    2013-07-01

    An experimental study was conducted to assess pyrochemical treatment options for degraded EBR-II fuel. As oxidized material, the degraded fuel would need to be converted back to metal to enable electrorefining within an existing electro-metallurgical treatment process. A lithium-based electrolytic reduction process was studied to assess the efficacy of converting oxide materials to metal with a particular focus on the impact of zirconium oxide and sodium oxide on this process. Bench-scale electrolytic reduction experiments were performed in LiCl-Li{sub 2}O at 650 C. degrees with combinations of manganese oxide (used as a surrogate for uranium oxide), zirconium oxide, and sodium oxide. In the absence of zirconium or sodium oxide, the electrolytic reduction of MnO showed nearly complete conversion to metal. The electrolytic reduction of a blend of MnO-ZrO{sub 2} in LiCl - 1 wt% Li{sub 2}O showed substantial reduction of manganese, but only 8.5% of the zirconium was found in the metal phase. The electrolytic reduction of the same blend of MnO-ZrO{sub 2} in LiCl - 1 wt% Li{sub 2}O - 6.2 wt% Na{sub 2}O showed substantial reduction of manganese, but zirconium reduction was even less at 2.4%. This study concluded that ZrO{sub 2} cannot be substantially reduced to metal in an electrolytic reduction system with LiCl - 1 wt% Li{sub 2}O at 650 C. degrees due to the perceived preferential formation of lithium zirconate. This study also identified a possible interference that sodium oxide may have on the same system by introducing a parasitic and cyclic reaction of dissolved sodium metal between oxidation at the anode and reduction at the cathode. When applied to oxidized sodium-bonded EBR-II fuel (e.g., U-10Zr), the prescribed electrolytic reduction system would not be expected to substantially reduce zirconium oxide, and the accumulation of sodium in the electrolyte could interfere with the reduction of uranium oxide, or at least render it less efficient.

  14. Experimental Validation of Multi-Epitope Peptides Including Promising MHC Class I- and II-Restricted Epitopes of Four Known Leishmania infantum Proteins.

    PubMed

    Agallou, Maria; Athanasiou, Evita; Koutsoni, Olga; Dotsika, Eleni; Karagouni, Evdokia

    2014-01-01

    Leishmaniasis is a significant worldwide health problem for which no vaccine exists. Activation of CD4(+) and CD8(+) T cells is crucial for the generation of protective immunity against parasite. Recent trend in vaccine design has been shifted to epitope-based vaccines that are more specific, safe, and easy to produce. In the present study, four known antigenic Leishmania infantum proteins, cysteine peptidase A (CPA), histone H1, KMP-11, and Leishmania eukaryotic initiation factor (LeIF) were analyzed for the prediction of binding epitopes to H2(d) MHC class I and II molecules, using online available algorithms. Based on in silico analysis, eight peptides including highly scored MHC class I- and II-restricted epitopes were synthesized. Peptide immunogenicity was validated in MHC compatible BALB/c mice immunized with each synthetic peptide emulsified in complete Freund's adjuvant/incomplete Freund's adjuvant. CPA_p2, CPA_p3, H1_p1, and LeIF_p6 induced strong spleen cell proliferation upon in vitro peptide re-stimulation. In addition, the majority of the peptides, except of LeIF_p1 and KMP-11_p1, induced IFN-γ secretion, while KMP-11_p1 indicated a suppressive effect on IL-10 production. CPA_p2, CPA_p3, LeIF_p3, and LeIF_p6 induced IFN-γ-producing CD4(+) T cells indicating a TH1-type response. In addition, CPA_p2, CPA_p3, and H1_p1 induced also the induction of CD8(+) T cells. The induction of peptide-specific IgG in immunized mice designated also the existence of B cell epitopes in peptide sequences. Combining immunoinformatic tools and experimental validation, we demonstrated that CPA_p2, CPA_p3, H1_p1, H1_p3, CPA_p2, LeIF_p3, and LeIF_p6 are likely to include potential epitopes for the induction of protective cytotoxic and/or TH1-type immune responses supporting the feasibility of peptide-based vaccine development for leishmaniasis. PMID:24959167

  15. Experimental and Computational Studies of the Macrocyclic Effect of an Auxiliary Ligand on Electron and Proton Transfers Within Ternary Copper(II)–Histidine Complexes

    SciTech Connect

    Song, Tao; Lam, Corey; Ng, Dominic C.; Orlova, G.; Laskin, Julia; Fang, De-Cai; Chu, Ivan K.

    2009-06-01

    The dissociation of [CuII(L)His]•2+ complexes [L = diethylenetriamine (dien) or 1,4,7-triazacyclononane (9-aneN3)] bears a strong resemblance to the previously reported behavior of [CuII(L)GGH]•2+ complexes. We have used low energy collision-induced dissociation experiments and density functional theory (DFT) calculations at the B3LYP/6-31+G(d) level to study the macrocyclic effect of the auxiliary ligands on the formation of His•+ from prototypical [CuII(L)His]•2+ systems. DFT revealed that the relative energy barriers of the same electron transfer (ET) dissociation pathways of [CuII(9-aneN3)His]•2+ and [CuII(dien)His]•2+ are very similar, with the ET reactions of [CuII(9-aneN3)His]•2+ leading to the generation of two distinct His•+ species; in contrast, the proton transfer (PT) dissociation pathways of [CuII(9-aneN3)His]•2+ and [CuII(dien)His]•2+ differ considerably. The PT reactions of [CuII(9-aneN3)His]•2+ are associated with substantially higher barriers (>13 kcal/mol) than those of [CuII(dien)His]•2+. Thus, the sterically encumbered auxiliary 9-aneN3 ligand facilitates ET reactions while moderating PT reactions, allowing the formation of hitherto non-observable histidine radical cations.

  16. Modeling of the oxidation of methyl esters - Validation for methyl hexanoate, methyl heptanoate, and methyl decanoate in a jet-stirred reactor

    SciTech Connect

    Glaude, Pierre Alexandre; Herbinet, Olivier; Bax, Sarah; Biet, Joffrey; Warth, Valerie; Battin-Leclerc, Frederique

    2010-11-15

    The modeling of the oxidation of methyl esters was investigated and the specific chemistry, which is due to the presence of the ester group in this class of molecules, is described. New reactions and rate parameters were defined and included in the software EXGAS for the automatic generation of kinetic mechanisms. Models generated with EXGAS were successfully validated against data from the literature (oxidation of methyl hexanoate and methyl heptanoate in a jet-stirred reactor) and a new set of experimental results for methyl decanoate. The oxidation of this last species was investigated in a jet-stirred reactor at temperatures from 500 to 1100 K, including the negative temperature coefficient region, under stoichiometric conditions, at a pressure of 1.06 bar and for a residence time of 1.5 s: more than 30 reaction products, including olefins, unsaturated esters, and cyclic ethers, were quantified and successfully simulated. Flow rate analysis showed that reactions pathways for the oxidation of methyl esters in the low-temperature range are similar to that of alkanes. (author)

  17. [Bis(quinolin-2-ylcarbon­yl)amido-κ3 N,N′,N′′]bromido­(N,N-di­methyl­formamide-κO)copper(II)

    PubMed Central

    Faizi, Md. Serajul Haque; Sen, Pratik

    2014-01-01

    In the mononuclear title complex, [CuBr(C20H12N3O2)(C3H7NO)], synthesized from the quinoline-derived reduced Schiff base 4-(quinolin-2-ylmeth­yl)amino­phenol, the coordination geometry around Cu2+ is distorted square-pyramidal, comprising a bromide anion at the apex [Cu—Br = 2.4671 (5) Å]. The base of the pyramid is built up from one di­methyl­formamide O-atom donor [Cu—O = 2.078 (2) Å] and three N-atom donors from the monoanionic, tridentate bis­(quinolin-2-ylcarbon­yl)di­imide ligand [Cu—Ndi­imide = 1.941 (3) Å, and Cu—Nquinol­yl = 2.060 (3) and 2.049 (3) Å]. An intra­molecular C—H⋯O occurs. In the crystal, weak methyl and aromatic C—H⋯Br and formyl C—H⋯Ocarbon­yl hydrogen-bonding inter­actions generate an overall layered structure lying parallel to (001). PMID:24940197

  18. Crystal structure of the inverse crown ether tetra­kis­[μ2-bis­(tri­methyl­sil­yl)amido]-μ4-oxido-dicobalt(II)disodium, [Co2Na2{μ2-N(SiMe3)2}4](μ4-O)

    PubMed Central

    Hansen, Christopher B.; Filatov, Alexander S.; Hillhouse, Gregory L.

    2016-01-01

    The title compound, [Co2Na2{μ2-N(SiMe3)2}4](μ4-O), (I), represents a new entry in the class of inverse crown ethers. In the mol­ecule, each Co atom is formally in the oxidation state +II. The structure contains one half of a unique mol­ecule per asymmetric unit with the central μ4-oxido ligand residing on an inversion center, leading to a planar coordination to the Na and Co atoms. In the crystal, bulky tri­methyl­silyl substituents prevent additional inter­actions with cobalt. However, weak inter­molecular Na⋯H3C—Si inter­actions form an infinite chain along [010]. The structure is isotypic with its Mg, Mn and Zn analogues. PMID:27308041

  19. Bis(μ-5-carboxyl­ato-1-carboxyl­ato­methyl-2-oxidopyridinium)-κ2 O 5:O 1;κ2 O 1:O 5-[diaqua­(phenan­throline-κ2 N,N′)manganese(II)] dihydrate

    PubMed Central

    Jiang, Mei-Xiang; Feng, Yun-Long

    2009-01-01

    The centrosymmetric binuclear title complex, [Mn2(C8H5NO5)2(C12H8N2)2(H2O)4]·2H2O, was obtained by the reaction of manganese chloride with 5-carb­oxy-1-carboxy­methyl-2-oxidopyridinium and 1,10-phenanthroline. The MnII atom is coordinated by two N atoms from the 1,10-phenanthroline ligand, two O atoms from two 5-carboxyl­ato-1-carboxyl­atomethyl-2-oxidopyridinium ligands and two water mol­ecules, leading to a distorted octahedral MnN2O4 environment. Inter­molecular O—H⋯O hydrogen bonds link neighbouring mol­ecules into a layer structure parallel to (001). PMID:21583018

  20. {N,N′-Bis­[2-(di­phenyl­phosphan­yl)ethan-1-yl­idene]ethyl­enedi­amine}bromido­(p-toluene­sulfonyl­methyl isocyanide)iron(II) tetra­phenyl­borate

    PubMed Central

    Sues, Peter E.; Lough, Alan J.; Morris, Robert H.

    2014-01-01

    In the title compound, [FeBr(C9H9NO2S)(C30H30N2P2)][B(C6H5)4], the FeII ion is in a distorted octa­hedral CBrN2P2 coordination geometry with a P—Fe—P angle of 109.95 (3)°. The relative orientation of the p-toluene­sulfonyl­methyl isocyanide ligand is defined by the C—S—C—N torsion angle of 67.1 (2)°. In the crystal, pairs of weak C—H⋯O hydrogen bonds connect the cations into inversion dimers, forming R 2 2(8) rings. PMID:24826104

  1. Growth-inhibitory Activity and Downregulation of the Class II Tumor-suppressor Gene H-rev107 in Tumor Cell Lines and Experimental Tumors

    PubMed Central

    Sers, Christine; Emmenegger, Urban; Husmann, Knut; Bucher, Katharina; Andres, Ann-Catherine; Schäfer, Reinhold

    1997-01-01

    The H-rev107 gene is a new class II tumor suppressor, as defined by its reversible downregulation and growth-inhibiting capacity in HRAS transformed cell lines. Overexpression of the H-rev107 cDNA in HRAS-transformed ANR4 hepatoma cells or in FE-8 fibroblasts resulted in 75% reduction of colony formation. Cell populations of H-rev107 transfectants showed an attenuated tumor formation in nude mice. Cells explanted from tumors or maintained in cell culture for an extended period of time no longer exhibited detectable levels of the H-rev107 protein, suggesting strong selection against H-rev107 expression in vitro and in vivo. Expression of the truncated form of H-rev107 lacking the COOH-terminal membrane associated domain of 25 amino acids, had a weaker inhibitory effect on proliferation in vitro and was unable to attenuate tumor growth in nude mice. The H-rev107 mRNA is expressed in most adult rat tissues, and immunohistochemical analysis showed expression of the protein in differentiated epithelial cells of stomach, of colon and small intestine, in kidney, bladder, esophagus, and in tracheal and bronchial epithelium. H-rev107 gene transcription is downregulated in rat cell lines derived from liver, kidney, and pancreatic tumors and also in experimental mammary tumors expressing a RAS transgene. In colon carcinoma cell lines only minute amounts of protein were detectable. Thus, downregulation of H-rev107 expression may occur at the level of mRNA or protein. PMID:9049257

  2. The radical mechanism of biological methane synthesis by methyl-coenzyme M reductase.

    PubMed

    Wongnate, Thanyaporn; Sliwa, Dariusz; Ginovska, Bojana; Smith, Dayle; Wolf, Matthew W; Lehnert, Nicolai; Raugei, Simone; Ragsdale, Stephen W

    2016-05-20

    Methyl-coenzyme M reductase, the rate-limiting enzyme in methanogenesis and anaerobic methane oxidation, is responsible for the biological production of more than 1 billion tons of methane per year. The mechanism of methane synthesis is thought to involve either methyl-nickel(III) or methyl radical/Ni(II)-thiolate intermediates. We employed transient kinetic, spectroscopic, and computational approaches to study the reaction between the active Ni(I) enzyme and substrates. Consistent with the methyl radical-based mechanism, there was no evidence for a methyl-Ni(III) species; furthermore, magnetic circular dichroism spectroscopy identified the Ni(II)-thiolate intermediate. Temperature-dependent transient kinetics also closely matched density functional theory predictions of the methyl radical mechanism. Identifying the key intermediate in methanogenesis provides fundamental insights to develop better catalysts for producing and activating an important fuel and potent greenhouse gas.

  3. The radical mechanism of biological methane synthesis by methyl-coenzyme M reductase.

    PubMed

    Wongnate, Thanyaporn; Sliwa, Dariusz; Ginovska, Bojana; Smith, Dayle; Wolf, Matthew W; Lehnert, Nicolai; Raugei, Simone; Ragsdale, Stephen W

    2016-05-20

    Methyl-coenzyme M reductase, the rate-limiting enzyme in methanogenesis and anaerobic methane oxidation, is responsible for the biological production of more than 1 billion tons of methane per year. The mechanism of methane synthesis is thought to involve either methyl-nickel(III) or methyl radical/Ni(II)-thiolate intermediates. We employed transient kinetic, spectroscopic, and computational approaches to study the reaction between the active Ni(I) enzyme and substrates. Consistent with the methyl radical-based mechanism, there was no evidence for a methyl-Ni(III) species; furthermore, magnetic circular dichroism spectroscopy identified the Ni(II)-thiolate intermediate. Temperature-dependent transient kinetics also closely matched density functional theory predictions of the methyl radical mechanism. Identifying the key intermediate in methanogenesis provides fundamental insights to develop better catalysts for producing and activating an important fuel and potent greenhouse gas. PMID:27199421

  4. Experimental and theoretical proton affinities of methionine, methionine sulfoxide and their N- and C-terminal derivatives

    NASA Astrophysics Data System (ADS)

    Lioe, Hadi; O'Hair, Richard A. J.; Gronert, Scott; Austin, Allen; Reid, Gavin E.

    2007-11-01

    The proton affinities of methionine, methionine sulfoxide and their derivatives (methionine methyl ester, methionine sulfoxide methyl ester, methionine methyl amide, methionine sulfoxide methyl amide, N-acetyl methionine, N-acetyl methionine sulfoxide, N-acetyl methionine methyl ester, N-acetyl methionine sulfoxide methyl ester, N-acetyl methionine methyl amide and N-acetyl methionine sulfoxide methyl amide) were experimentally determined using the kinetic method, in which proton bound dimers formed via electrospray ionization (ESI) were subjected to collision induced dissociation (CID) in a triple quadrupole mass spectrometer. In addition, theoretical calculations carried out at the MP2/6-311 + G(2d,p)//B3LYP/6-31 + G(d,p) level of theory to determine the global minima of the neutral and protonated species of all derivatives studied, were used to predict theoretical proton affinities. The density function theory calculations not only support the experimental proton affinities, but also provide structural insights into the types of hydrogen bonding that stabilize the neutral and protonated methionine or methionine sulfoxide derivatives. Comparison of the proton affinities of the various methionine and methionine sulfoxide derivatives reveals that: (i) oxidation of methionine derivatives to methionine sulfoxide derivatives results in an increase in proton affinity due to higher intrinsic proton affinity and an increase in the ring size formed through charge complexation of the sulfoxide group, which allows more efficient hydrogen bonding compared to the sulfide group; (ii) C-terminal modification by methyl esterification or methyl amidation increases the proton affinity in the order of methyl amide > methyl ester > carboxylic acid due to improved charge stabilization; (iii) N-terminal modification by N-acetylation decreases proton affinity of the derivatives due to lower intrinsic proton affinity of the N-acetyl group as well as due to stabilization of the attached

  5. Crystal structure of bis­{N-[2-(di­methyl­amino)­eth­yl]quinolin-8-amine-κ3 N,N′,N′′}nickel(II) dichloride 3.5-hydrate

    PubMed Central

    Kariuki, Benson M.; Al-Sudani, Abdul-Razak H.

    2014-01-01

    In the title compound, [Ni(C13H17N3)2]Cl2·3.5H2O, the geom­etry of the NiN6 complex cation is slightly distorted octa­hedral, with a facial arrangement of the two tridentate N-[2-(di­­methyl­amino)­eth­yl]quinolin-8-amine ligands around the metal ion. The asymmetric unit consists of two independent complex half-mol­ecules located on centres of inversion, together with two chloride counter-anions and 3.5 water mol­ecules of solvation, one of which is disordered across an inversion centre. In the crystal, O—H⋯O, O—H⋯Cl and N—H⋯Cl hydrogen-bonding inter­actions form a three-dimensional network structure. PMID:25309190

  6. In vitro Methylation Assay to Study Protein Arginine Methylation

    PubMed Central

    Bikkavilli, Rama Kamesh; Avasarala, Sreedevi; Van Scoyk, Michelle; Karuppusamy Rathinam, Manoj Kumar; Tauler, Jordi; Borowicz, Stanley; Winn, Robert A.

    2014-01-01

    Protein arginine methylation is one of the most abundant post-translational modifications in the nucleus. Protein arginine methylation can be identified and/or determined via proteomic approaches, and/or immunoblotting with methyl-arginine specific antibodies. However, these techniques sometimes can be misleading and often provide false positive results. Most importantly, these techniques cannot provide direct evidence in support of the PRMT substrate specificity. In vitro methylation assays, on the other hand, are useful biochemical assays, which are sensitive, and consistently reveal if the identified proteins are indeed PRMT substrates. A typical in vitro methylation assay includes purified, active PRMTs, purified substrate and a radioisotope labeled methyl donor (S-adenosyl-L-[methyl-3H] methionine). Here we describe a step-by-step protocol to isolate catalytically active PRMT1, a ubiquitously expressed PRMT family member. The methyl transferase activities of the purified PRMT1 were later tested on Ras-GTPase activating protein binding protein 1 (G3BP1), a known PRMT substrate, in the presence of S-adenosyl-L-[methyl-3H] methionine as the methyl donor. This protocol can be employed not only for establishing the methylation status of novel physiological PRMT1 substrates, but also for understanding the basic mechanism of protein arginine methylation. PMID:25350748

  7. DNA methylation and histone modification in onion chromosomes.

    PubMed

    Suzuki, Go; Shiomi, Maho; Morihana, Sayuri; Yamamoto, Maki; Mukai, Yasuhiko

    2010-01-01

    Onion, Allium cepa, is a model plant for experimental observation of somatic cell division, whose mitotic chromosome is extremely large, and contains the characteristic terminal heterochromatin. Epigenetic status of the onion chromosome is a matter of deep interest from a molecular cytogenetic point of view, because epigenetic marks regulate chromatin structure and gene expression. Here we examined chromosomal distribution of DNA methylation and histone modification in A. cepa in order to reveal the chromatin structure in detail. Immunodetection of 5-methylcytosine (5mC) and in situ nick-translation analysis showed that onion genomic DNA was highly methylated, and the methylated CG dinucleotides were distributed in entire chromosomes. In addition, distributions of histone methylation codes, which occur in close association with DNA methylation, were similar to those of other large genome species. From these results, a highly heterochromatic and less euchromatic state of large onion chromosomes were demonstrated at an epigenetic level.

  8. Methyl isobutyl ketone (MIBK)

    Integrated Risk Information System (IRIS)

    EPA / 635 / R - 03 / 002 TOXICOLOGICAL REVIEW OF METHYL ISOBUTYL KETONE ( CAS No . 108 - 10 - 1 ) In Support of Summary Information on the Integrated Risk Information System ( IRIS ) March 2003 U.S . Environmental Protection Agency Washington DC DISCLAIMER This document has been reviewed in accordan

  9. Haloxyfop-methyl

    Integrated Risk Information System (IRIS)

    Haloxyfop - methyl ; CASRN 69806 - 40 - 2 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinoge

  10. Thiophanate-methyl

    Integrated Risk Information System (IRIS)

    Thiophanate - methyl ; CASRN 23564 - 05 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcino

  11. Chloromethyl methyl ether (CMME)

    Integrated Risk Information System (IRIS)

    Chloromethyl methyl ether ( CMME ) ; CASRN 107 - 30 - 2 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments fo

  12. Methyl ethyl ketone (MEK)

    Integrated Risk Information System (IRIS)

    Methyl ethyl ketone ( MEK ) ( CASRN 78 - 93 - 3 ) Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Nonc

  13. Pirimiphos-methyl

    Integrated Risk Information System (IRIS)

    Pirimiphos - methyl ; CASRN 29232 - 93 - 7 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinog

  14. DNA Methylation in Osteoarthritis.

    PubMed

    den Hollander, Wouter; Meulenbelt, Ingrid

    2015-12-01

    Osteoarthritis (OA) is a prevalent disease of articular joints and primarily characterized by degradation and calcification of articular cartilage. Presently, no effective treatment other than pain relief exists and patients ultimately need to undergo replacement surgery of the affected joint. During disease progression articular chondrocytes, the single cell type present in articular cartilage, show altered transcriptional profiles and undergo phenotypic changes that resemble the terminal differentiation route apparent in growth plate chondrocytes. Hence, given its prominent function in both regulating gene expression and maintaining cellular phenotypes, DNA methylation of CpG dinucleotides is intensively studied in the context of OA. An increasing number of studies have been published that employed a targeted approach on genes known to play a role in OA pathophysiology. As of such, it has become clear that OA responsive DNA methylation changes seem to mediate disease associated aberrant gene expression. Furthermore, established OA susceptibility alleles such as GDF5 and DIO2 appear to confer OA risk via DNA methylation and respective pathophysiological expression changes. In more recent years, genome wide profiling of DNA methylation in OA affected articular cartilage has emerged as a powerful tool to address the epigenetic changes in their entirety, which has resulted in the identification of putative patient subgroups as well as generic OA associated pathways. PMID:27019616

  15. Kenaf methyl esters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Additional or alternative feedstocks are one of the major areas of interest regarding biodiesel. In this paper, for the first time, the fuel properties of kenaf (Hibiscus cannabinus L.) seed oil methyl esters are comprehensively reported. This biodiesel is also relatively unique by containing small ...

  16. DNA Methylation and Cancer Diagnosis

    PubMed Central

    Delpu, Yannick; Cordelier, Pierre; Cho, William C.; Torrisani, Jérôme

    2013-01-01

    DNA methylation is a major epigenetic modification that is strongly involved in the physiological control of genome expression. DNA methylation patterns are largely modified in cancer cells and can therefore be used to distinguish cancer cells from normal tissues. This review describes the main technologies available for the detection and the discovery of aberrantly methylated DNA patterns. It also presents the different sources of biological samples suitable for DNA methylation studies. We discuss the interest and perspectives on the use of DNA methylation measurements for cancer diagnosis through examples of methylated genes commonly documented in the literature. The discussion leads to our consideration for why DNA methylation is not commonly used in clinical practice through an examination of the main requirements that constitute a reliable biomarker. Finally, we describe the main DNA methylation inhibitors currently used in clinical trials and those that exhibit promising results. PMID:23873296

  17. Predicting methyl iodide emission, soil concentration, and pest control in a two-dimensional chamber system.

    PubMed

    Luo, Lifang; Yates, Scott R; Ashworth, Daniel J

    2011-01-01

    Due to ever-increasing state and federal regulations, the future use of fumigants is predicted on reducing negative environmental impacts while offering sufficient pestcontrol efficacy. To foster the development of a best management practice, an integrated tool is needed to simultaneously predict fumigant movement and pest control without having to conduct elaborate and costly experiments. The objective of this study was (i) to present a two-dimensional (2-D) mathematical model to describe both fumigant movement and pestcontrol and (ii) to evaluate the model by comparing the simulated and observed results. Both analytical and numerical methods were used to predict methyl iodide (MeI) transport and fate. To predict pest control efficacy, the concentration-time index (CT) was defined and a two-parameter logistic survival model was used. Dose-response curves were experimentally determined for MeI against three types of pests (barnyardgrass [Echinochloa crus-galli] seed, citrus nematode [Tylenchulus semipenetrans], and fungi [Fusarium oxysporum]). Methyl iodide transport and pest control measurements collected from a 2-D experiimental system (60 by 60 cm) were used to test the model. Methyl iodide volatilization rates and soil gas-phase concentrations over time were accurately simulated by the model. The mass balance analysis indicates that the fraction of MeI degrading in the soil was underestimated when determined by the appearance of iodide concentration. The experimental results showed that after 24 h of MeI fumigation in the 2-D soil chamber, fungal population was not suppressed; > 90% of citrus nematodes were killed; and barnyardgrass seeds within 20-cm distance from the center were affected. These experimental results were consistent with the predicted results. The model accurately estimated the MeI movement and control of various pests and is a powerful tool to evaluate pesticides in terms of their negative environmental impacts and pest control under various

  18. Genome-wide analysis of methylation in bovine clones by methylated DNA immunoprecipitation (MeDIP).

    PubMed

    Kiefer, Hélène

    2015-01-01

    Methylated DNA immunoprecipitation (MeDIP), when coupled to high-throughput sequencing or microarray hybridization, allows for the identification of methylated loci at a genome-wide scale. Genomic regions affected by incomplete reprogramming after nuclear transfer can potentially be delineated by comparing the MeDIP profiles of bovine clones and non-clones. This chapter presents a MeDIP protocol largely inspired from Mohn and colleagues (Mohn et al., Methods Mol Biol 507:55-64, 2009), with PCR primers specific for cattle, and when possible, overviews of experimental designs adapted to the comparison between clones and non-clones.

  19. Crystal structure of (2-amino-7-methyl-4-oxido­pteridine-6-carboxyl­ato-κ3 O 4,N 5,O 6)aqua­(1,10-phenanthroline-κ2 N,N′)copper(II) trihydrate

    PubMed Central

    Baisya, Siddhartha S.; Roy, Parag S.

    2014-01-01

    In the title compound, [Cu(C8H5N5O3)(C12H8N2)(H2O)]·3H2O, the CuII cation is O,N,O′-chelated by the 2-amino-7-methyl-4-oxidopteridine-6-carboxyl­ate anion and N,N′-chelated by the 1,10-phenanthroline (phen) ligand. A water mol­ecule further coordinates to the CuII cation to complete the elongated distorted octa­hedral coordination geometry. In the mol­ecule, the pteridine ring system is essentially planar [maximum deviation = 0.055 (4) Å], and its mean plane is nearly perpendicular to the phen ring system [dihedral angle = 85.97 (3)°]. In the crystal, N—H⋯O, O—H⋯N and O—H⋯·O hydrogen bonds, as well as weak C—H⋯O hydrogen bonds and C—H⋯π inter­actions, link the complex mol­ecules and lattice water mol­ecules into a three-dimensional supra­molecular architecture. Extensive π–π stacking between nearly parallel aromatic rings of adjacent mol­ecules are also observed, the centroid-to-centroid distances being 3.352 (2), 3.546 (3), 3.706 (3) and 3.744 (3) Å. PMID:25484742

  20. Crystal structure of bis­(μ2-tetra­bromo­phthalato-κ2 O 1:O 2)bis[aqua(N,N,N′,N′-tetra­methyl­ethane-1,2-di­amine-κ2 N,N′)copper(II)

    PubMed Central

    Tobón-Trujillo, Luis Manuel; Villanueva-Sánchez, Luis Felipe; Martínez-Otero, Diego; Dorazco-González, Alejandro

    2015-01-01

    In the title complex, [Cu2(C8Br4O4)2(C6H16N2)2(H2O)2], the CuII cation is chelated by a tetra­methyl­ethane-1,2-di­amine ligand and coordinated by a water mol­ecule as well as bridged by two tetra­bromo­phthalate anions in a distorted O3N2 trigonal–bipyramidal geometry. The two symmetry-related tetra­bromo­phthalate anions bridge the two CuII cations, forming a centrosymmetric dinuclear complex in which the Cu⋯Cu separation is 5.054 (2) Å. Intra­molecular classic O—H⋯O hydrogen bonds and weak C—H⋯O hydrogen bonds occur in the dinuclear mol­ecule. In the crystal, the mol­ecules are linked by weak C—H⋯Br and C—H⋯O inter­actions into supra­molecular chains propagating along the b-axis direction. PMID:26396871