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  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.

  3. Mercury methylation rates for geochemically relevant Hg(II) species in sediments.

    PubMed

    Jonsson, Sofi; Skyllberg, Ulf; Nilsson, Mats B; Westlund, Per-Olof; Shchukarev, Andrey; Lundberg, Erik; Björn, Erik

    2012-11-06

    Monomethylmercury (MeHg) in fish from freshwater, estuarine, and marine environments is a major global environmental issue. Mercury levels in biota are mainly controlled by the methylation of inorganic mercuric mercury (Hg(II)) to MeHg in water, sediments, and soils. There is, however, a knowledge gap concerning the mechanisms and rates of methylation of specific geochemical Hg(II) species. Such information is crucial for a better understanding of variations in MeHg concentrations among ecosystems and, in particular, for predicting the outcome of currently proposed measures to mitigate mercury emissions and reduce MeHg concentrations in fish. To fill this knowledge gap we propose an experimental approach using Hg(II) isotope tracers, with defined and geochemically important adsorbed and solid Hg(II) forms in sediments, to study MeHg formation. We report Hg(II) methylation rate constants, k(m), in estuarine sediments which span over 2 orders of magnitude depending on chemical form of added tracer: metacinnabar (β-(201)HgS(s)) < cinnabar (α-(199)HgS(s)) < Hg(II) reacted with mackinawite (≡FeS-(202)Hg(II)) < Hg(II) bonded to natural organic matter (NOM-(196)Hg(II)) < a typical aqueous tracer ((198)Hg(NO(3))(2)(aq)). We conclude that a combination of thermodynamic and kinetic effects of Hg(II) solid-phase dissolution and surface desorption control the Hg(II) methylation rate in sediments and cause the large observed differences in k(m)-values. The selection of relevant solid-phase and surface-adsorbed Hg(II) tracers will therefore be crucial to achieving biogeochemically accurate estimates of ambient Hg(II) methylation rates.

  4. Mechanisms of Hg(II) uptake and methylation in methylating bacteria

    SciTech Connect

    Morel, Francois M. M.

    2016-10-14

    The goal of this project was to understand the critical factors which control the availability and transport of Hg(II) into cells, a first step in the production of the neurotoxin, methylmercury. Specifically, this research focused on understanding the mechanism of bacterial mercury uptake and how mercury speciation affects the specificity and kinetics of mercury transport. Our research has shown that Hg(II) uptake in three different iron and sulfate-reducing proteobacteria occurs by the following mechanism (1) : Hg(II) uptake is an active transport process requiring energy, (2) it is dependent upon the structure of the Hg binding ligand, and (3) it is mediated by a heavy metal transporter such as one which transports the essential metal, Zn(II). In order to determine whether this mechanism extends to more diverse phylogenetic groups, we have begun examining Hg(II) uptake and bioavailability in two representative Hg methylating strains within the Firmicutes. These organisms have remarkably different membrane structures distinct from the Proteobacteria. Our results show low uptake rates in these two species of Firmicutes relative to the previously characterized Proteobacteria. This may explain the low methylation rates and yields observed in these organisms. Most surprisingly, however, these organisms appear to take up Hg(II) passively, as the addition of a protonophore failed to reduce Hg(II) uptake in these organisms. This is quite different to what has been observed previously for the Proteobacteria and suggests a different mechanism for Hg(II) uptake in the Firmicutes. We are continuing to understand and describe Hg(II) uptake in these organisms. A manuscript is expected to be submitted on this research in June 2016.

  5. Topoisomerase II regulates the maintenance of DNA methylation.

    PubMed

    Lu, Lin-Yu; Kuang, Henry; Korakavi, Gautam; Yu, Xiaochun

    2015-01-09

    The maintenance of DNA methylation in nascent DNA is a critical event for numerous biological processes. Following DNA replication, DNMT1 is the key enzyme that strictly copies the methylation pattern from the parental strand to the nascent DNA. However, the mechanism underlying this highly specific event is not thoroughly understood. In this study, we identified topoisomerase IIα (TopoIIα) as a novel regulator of the maintenance DNA methylation. UHRF1, a protein important for global DNA methylation, interacts with TopoIIα and regulates its localization to hemimethylated DNA. TopoIIα decatenates the hemimethylated DNA following replication, which might facilitate the methylation of the nascent strand by DNMT1. Inhibiting this activity impairs DNA methylation at multiple genomic loci. We have uncovered a novel mechanism during the maintenance of DNA methylation. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  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. 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.

  8. Geosynthesis of organic compounds: II. Methylation of phenanthrene and alkylphenanthrenes

    NASA Astrophysics Data System (ADS)

    Alexander, Robert; Bastow, Trevor P.; Fisher, Steven J.; Kagi, Robert I.

    1995-10-01

    A crude oil and several shales which contain anomalously high concentrations of phenanthrene, 1-methylphenanthrene, 1,7-dimethylphenathrene, and retene have been shown to contain relatively high concentrations of their corresponding 9-methyl counterparts. In laboratory experiments carried out under mild conditions, each of the phenanthrenes has been shown to be substituted preferentially at the 9-position when a methyl donor was heated with the substrate in the presence of a clay catalyst. These observations have been interpreted as evidence for a sedimentary methylation process.

  9. 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

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

    PubMed Central

    Schaefer, Jeffra K.; Rocks, Sara S.; Zheng, Wang; Liang, Liyuan; Gu, Baohua; Morel, François M. 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. PMID:21555571

  11. Irradiation behavior of experimental Mark-II Experimental Breeder Reactor II driver fuel

    SciTech Connect

    Hofman, G.L.

    1980-01-01

    Prototypic driver-fuel elements using metallic fuel and stainless-steel cladding, designed to achieve a high burnup, were tested in the Experimental Breeder Reactor II. The irradiation results showed that burnup of up to 10 at.% can be attained without cladding failure and that cladding deformation can be kept to acceptable values if Type 316 stainless steel is used as the cladding material.

  12. 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.

  13. Dichloridobis[2-methyl-sulfanyl-4-(pyridin-2-yl)pyrimidine-κN,N]cobalt(II).

    PubMed

    Yang, Wen-Na

    2011-09-01

    The asymmetric unit of the title compound, [CoCl(2)(C(10)H(9)N(3)S)(2)], contains one half-mol-ecule with the Co(II) atom situtated on a twofold rotational axis. The Co(II) atom, in an octa-hedral enviroment, is coordinated by four N atoms from two 2-methyl-sulfanyl-4-(pyridin-2-yl)pyrimidine ligands and two Cl atoms.

  14. Tumor LINE-1 Methylation Level in Association with Survival of Patients with Stage II Colon Cancer

    PubMed Central

    Swets, Marloes; Zaalberg, Anniek; Boot, Arnoud; van Wezel, Tom; Frouws, Martine A.; Bastiaannet, Esther; Gelderblom, Hans; van de Velde, Cornelis J. H.; Kuppen, Peter J. K.

    2016-01-01

    Genome-wide DNA hypomethylation is associated with a worse prognosis in early-stage colorectal cancer. To measure genome-wide DNA methylation levels, long interspersed nucleotide element (LINE-1) repeats are used as a surrogate marker. Cohort studies on the clinical impact of genome-wide DNA methylation level in patients with only early-stage colon cancer, are currently lacking. This study aimed to investigate the prognostic value of LINE-1 methylation in a stage II colon cancer cohort (n = 164). Manual needle microdissection of tumor areas was performed on formalin-fixed paraffin-embedded tumor tissue sections followed by DNA extraction. Bisulfite converted DNA was used to assess tumor LINE-1 methylation level by qPCR. Patients with LINE-1 hypomethylated tumors had a significantly worse overall survival compared to patients with a higher level of LINE-1 tumor DNA methylation (HR 1.68, 95% CI 1.03–2.75; p = 0.04). This effect was more prominent in patients aged over 65 years (HR 2.00, 95% CI 1.13–3.52; p = 0.02), although the test for age interaction was not significant. No significant effect on recurrence-free survival was observed. Based on these results, tumor LINE-1 hypomethylation is associated with a worse overall survival in stage II colon cancer. Whether the origin of this causation is cancer-specific or age-related can be debated. PMID:28035987

  15. Tumor LINE-1 Methylation Level in Association with Survival of Patients with Stage II Colon Cancer.

    PubMed

    Swets, Marloes; Zaalberg, Anniek; Boot, Arnoud; van Wezel, Tom; Frouws, Martine A; Bastiaannet, Esther; Gelderblom, Hans; van de Velde, Cornelis J H; Kuppen, Peter J K

    2016-12-27

    Genome-wide DNA hypomethylation is associated with a worse prognosis in early-stage colorectal cancer. To measure genome-wide DNA methylation levels, long interspersed nucleotide element (LINE-1) repeats are used as a surrogate marker. Cohort studies on the clinical impact of genome-wide DNA methylation level in patients with only early-stage colon cancer, are currently lacking. This study aimed to investigate the prognostic value of LINE-1 methylation in a stage II colon cancer cohort (n = 164). Manual needle microdissection of tumor areas was performed on formalin-fixed paraffin-embedded tumor tissue sections followed by DNA extraction. Bisulfite converted DNA was used to assess tumor LINE-1 methylation level by qPCR. Patients with LINE-1 hypomethylated tumors had a significantly worse overall survival compared to patients with a higher level of LINE-1 tumor DNA methylation (HR 1.68, 95% CI 1.03-2.75; p = 0.04). This effect was more prominent in patients aged over 65 years (HR 2.00, 95% CI 1.13-3.52; p = 0.02), although the test for age interaction was not significant. No significant effect on recurrence-free survival was observed. Based on these results, tumor LINE-1 hypomethylation is associated with a worse overall survival in stage II colon cancer. Whether the origin of this causation is cancer-specific or age-related can be debated.

  16. 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.

  17. Phase I/II study of azacitidine and capecitabine/oxaliplatin (CAPOX) in refractory CIMP-high metastatic colorectal cancer: evaluation of circulating methylated vimentin

    PubMed Central

    Overman, Michael J.; Morris, Van; Moinova, Helen; Manyam, Ganiraju; Ensor, Joe; Lee, Michael S.; Eng, Cathy; Kee, Bryan; Fogelman, David; Shroff, Rachna T.; LaFramboise, Thomas; Mazard, Thibault; Feng, Tian; Hamilton, Stanley; Broom, Bradley; Lutterbaugh, James; Issa, Jean-Pierre; Markowitz, Sanford D.; Kopetz, Scott

    2016-01-01

    Purpose Hypermethylation of promoter CpG islands (CIMP) has been strongly implicated in chemotherapy resistance and is implicated in the pathogenesis of a subset of colorectal cancers (CRCs) termed CIMP-high. Experimental Design This phase I/II study in CRC (phase II portion restricted to CIMP-high CRC), treated fluoropyrimidine/oxaliplatin refractory patients with azacitidine (75 mg/m2/day subcutaneously D1-5) and CAPOX (capecitibine and oxaliplatin) every three weeks. Results Twenty-six patients (pts) were enrolled in this study: 15 pts (12 treated at MTD) in phase I and 11 pts in phase II. No dose limiting toxicities were observed. A total of 14 pts were CIMP-high. No responses were seen. CIMP-high status did not correlate with efficacy endpoints [stable disease (SD) or progression-free survival (PFS)] or baseline vimentin methylation level. Changes in vimentin methylation over time did not correlate with efficacy outcomes. Baseline methylated vimentin correlated with tumor volume (P<0.001) and higher levels of baseline methylation correlated with the obtainment of stable disease (P=0.04). Conclusions Azacitidine and CAPOX were well tolerated with high rates of stable disease in CIMP-high pts, but no objective responses. Serum methylated vimentin may be associated with benefit from a regimen including a hypomethylation agent, although this study is not able to separate a potential prognostic or predictive role for the biomarker. PMID:27542211

  18. 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/

  19. Continuous production of biodiesel under supercritical methyl acetate conditions: Experimental investigation and kinetic model.

    PubMed

    Farobie, Obie; Matsumura, Yukihiko

    2017-10-01

    In this study, biodiesel production by using supercritical methyl acetate in a continuous flow reactor was investigated for the first time. The aim of this study was to elucidate the reaction kinetics of biodiesel production by using supercritical methyl. Experiments were conducted at various reaction temperatures (300-400°C), residence times (5-30min), oil-to-methyl acetate molar ratio of 1:40, and a fixed pressure of 20MPa. Reaction kinetics of biodiesel production with supercritical methyl acetate was determined. Finally, biodiesel yield obtained from this method was compared to that obtained with supercritical methanol, ethanol, and MTBE (methyl tertiary-butyl ether). The results showed that biodiesel yield with supercritical methyl acetate increased with temperature and time. The developed kinetic model was found to fit the experimental data well. The reactivity of supercritical methyl acetate was the lowest, followed by that of supercritical MTBE, ethanol, and methanol, under the same conditions. Copyright © 2017. Published by Elsevier Ltd.

  20. 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.

  1. 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.

  2. Analysis of RET promoter CpG island methylation using methylation-specific PCR (MSP), pyrosequencing, and methylation-sensitive high-resolution melting (MS-HRM): impact on stage II colon cancer patient outcome.

    PubMed

    Draht, Muriel X G; Smits, Kim M; Jooste, Valérie; Tournier, Benjamin; Vervoort, Martijn; Ramaekers, Chantal; Chapusot, Caroline; Weijenberg, Matty P; van Engeland, Manon; Melotte, Veerle

    2016-01-01

    Already since the 1990s, promoter CpG island methylation markers have been considered promising diagnostic, prognostic, and predictive cancer biomarkers. However, so far, only a limited number of DNA methylation markers have been introduced into clinical practice. One reason why the vast majority of methylation markers do not translate into clinical applications is lack of independent validation of methylation markers, often caused by differences in methylation analysis techniques. We recently described RET promoter CpG island methylation as a potential prognostic marker in stage II colorectal cancer (CRC) patients of two independent series. In the current study, we analyzed the RET promoter CpG island methylation of 241 stage II colon cancer patients by direct methylation-specific PCR (MSP), nested-MSP, pyrosequencing, and methylation-sensitive high-resolution melting (MS-HRM). All primers were designed as close as possible to the same genomic region. In order to investigate the effect of different DNA methylation assays on patient outcome, we assessed the clinical sensitivity and specificity as well as the association of RET methylation with overall survival for three and five years of follow-up. Using direct-MSP and nested-MSP, 12.0 % (25/209) and 29.6 % (71/240) of the patients showed RET promoter CpG island methylation. Methylation frequencies detected by pyrosequencing were related to the threshold for positivity that defined RET methylation. Methylation frequencies obtained by pyrosequencing (threshold for positivity at 20 %) and MS-HRM were 13.3 % (32/240) and 13.8 % (33/239), respectively. The pyrosequencing threshold for positivity of 20 % showed the best correlation with MS-HRM and direct-MSP results. Nested-MSP detected RET promoter CpG island methylation in deceased patients with a higher sensitivity (33.1 %) compared to direct-MSP (10.7 %), pyrosequencing (14.4 %), and MS-HRM (15.4 %). While RET methylation frequencies detected by nested

  3. Novel effects of methyl viologen on photosystem II function in spinach leaves.

    PubMed

    Fan, Da-Yong; Jia, Husen; Barber, James; Chow, Wah Soon

    2009-12-01

    Methyl viologen (MV) is a well-known electron mediator that works on the acceptor side of photosystem I. We investigated the little-known, MV-induced inhibition of linear electron flow through photosystem II (PS II) in spinach-leaf discs. Even a low [MV] decreased the (1) average, light-adapted photochemical efficiency of PS II traps, (2) oxidation state of the primary quinone acceptor Q(A) in PS II during illumination, (3) photochemical efficiency of light-adapted open PS II traps, (4) fraction of absorbed light energy dissipated constitutively in a light-independent manner or as chlorophyll (Chl) a fluorescence emission, (5) Chl a fluorescence yield corresponding to dark-adapted open reaction-center traps (F (o)) and closed reaction-center traps (F (m)), and (6) half-time for re-oxidation of Q (A) (-) in PS II after a single-turnover flash. These effects suggest that the presence of MV accelerates various "downhill" electron-transfer steps in PS II. Therefore, when using the MV to quantify cyclic electron flow, the inhibitory effect of MV on PS II should be taken into account.

  4. 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.

  5. 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.

  6. Synthesis, structural features, and methyl methacrylate polymerisation of binuclear zinc(II) complexes with tetradentate pyrazolyl ligands

    NASA Astrophysics Data System (ADS)

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

    2014-04-01

    The reaction of ZnCl2 with ancillary ligands, including 1,4-bis-(N,N-di-(1H-pyrazolyl-1-methyl)amine)benzene (L1) and 4,4‧-bis-(N,N-di(1H-pyrazolyl-1-methyl)phenyl)methane (L2), in ethanol yields Zn(II) chloride complexes, i.e., 1,4-bis-(N,N-di-(1H-pyrazolyl-1-methyl)amine)benzene(dichloro)Zn(II) [L1Zn2Cl4] and 4,4‧-bis-(N,N-di-(1H-pyrazolyl-1-methyl)phenyl)methane(dichloro)Zn(II) [L2Zn2Cl4]. The X-ray crystal structures of Zn(II) complexes revealed that they are binuclear, and each zinc atom has a distorted tetrahedral geometry which involves a nitrogen atom from two pyrazole groups and two chloro ligands. The catalytic activity of [L1Zn2Cl4] and [L2Zn2Cl4] for the polymerisation of methyl methacrylate (MMA) in the presence of modified methylaluminoxane (MMAO) increased by twofold compared to the corresponding monomeric Zn(II) complex, N,N-bis(1H-pyrazolyl-1-methyl)aniline(dichloro)Zn(II) [LZnCl2], at 60 °C.

  7. Protein arginine methyltransferase 1 (PRMT1) represses MHC II transcription in macrophages by methylating CIITA

    PubMed Central

    Fan, Zhiwen; Li, Jianfei; Li, Ping; Ye, Qing; Xu, Huihui; Wu, Xiaoyan; Xu, Yong

    2017-01-01

    Efficient presentation of alien antigens triggers activation of T lymphocytes and robust host defense against invading pathogens. This pathophysiological process relies on the expression of major histocompatibility complex (MHC) molecules in antigen presenting cells such as macrophages. Aberrant MHC II transactivation plays a crucial role in the pathogenesis of atherosclerosis. Class II transactivator (CIITA) mediates MHC II induction by interferon gamma (IFN-γ). CIITA activity can be fine-tuned at the post-translational level, but the mechanisms are not fully appreciated. We investigated the role of protein arginine methyltransferase 1 (PRMT1) in this process. We report here that CIITA interacted with PRMT1. IFN-γ treatment down-regulated PRMT1 expression and attenuated PRMT1 binding on the MHC II promoter. Over-expression of PRMT1 repressed MHC II promoter activity while PRMT1 depletion enhanced MHC II transactivation. Mechanistically, PRMT1 methylated CIITA and promoted CIITA degradation. Therefore, our data reveal a previously unrecognized role for PRMT1 in suppressing CIITA-mediated MHC II transactivation. PMID:28094290

  8. 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)

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

    PubMed Central

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

    2013-01-01

    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 × 10−3 and 5.2 × 10−4) 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 HO2 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. PMID:23710077

  10. Experimental and modeling study of the thermal decomposition of methyl decanoate

    PubMed Central

    Herbinet, Olivier; Glaude, Pierre-Alexandre; Warth, Valérie; Battin-Leclerc, Frédérique

    2013-01-01

    The experimental study of the thermal decomposition of methyl decanoate was performed in a jet-stirred reactor at temperatures ranging from 773 to 1123 K, at residence times between 1 and 4 s, at a pressure of 800 Torr (106.6 kPa) and at high dilution in helium (fuel inlet mole fraction of 0.0218). Species leaving the reactor were analyzed by gas chromatography. Main reaction products were hydrogen, carbon oxides, small hydrocarbons from C1 to C3, large 1-olefins from 1-butene to 1-nonene, and unsaturated esters with one double bond at the end of the alkyl chain from methyl-2-propenoate to methyl-8-nonenoate. At the highest temperatures, the formation of polyunsaturated species was observed: 1,3-butadiene, 1,3-cyclopentadiene, benzene, toluene, indene, and naphthalene. These results were compared with previous ones about the pyrolysis of n-dodecane, an n-alkane of similar size. The reactivity of both molecules was found to be very close. The alkane produces more olefins while the ester yields unsaturated oxygenated compounds. A detailed kinetic model for the thermal decomposition of methyl decanoate has been generated using the version of software EXGAS which was updated to take into account the specific chemistry involved in the oxidation of methyl esters. This model contains 324 species and 3231 reactions. It provided a very good prediction of the experimental data obtained in jet-stirred reactor. The formation of the major products was analyzed. The kinetic analysis showed that the retro-ene reactions of intermediate unsaturated methyl esters are of importance in low reactivity systems. PMID:23710078

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

    PubMed

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

    2010-06-01

    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 × 10(-3) and 5.2 × 10(-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 HO2 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.

  12. 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.

  13. 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

  14. Uptake of Pb(II) and Cd(II) on Chitosan Microsphere Surface Successively Grafted by Methyl Acrylate and Diethylenetriamine.

    PubMed

    Zhang, Haifeng; Dang, Qifeng; Liu, Chengsheng; Cha, Dongsu; Yu, Zhenzhen; Zhu, Wenjing; Fan, Bing

    2017-03-29

    A novel adsorbent, CS-MA-DETA microspheres, for uptake of heavy metal ions from aqueous solutions was first fabricated via two-step grafting methyl acrylate (MA) and diethylenetriamine (DETA) onto chitosan (CS) microsphere surface in the absence of cross-linkers. CS-MA-DETA microspheres of 3.04 μm in mean diameter were of uniformly wrinkle-like topography sketched out by SEM, whose surface after decoration by MA and DETA was stable and beneficial to metal ion capture. Its chemical composition, microstructure, and thermal property were characterized by elemental analysis, FTIR, XRD, BET, and TGA techniques, and the achieved quantitative results mainly included C/N ratio (4.76), crystallinity (31.20%, 19.75% of CS), specific surface area (27.806 m(2) g(-1)), pore diameter (3.452 nm), and mass loss at the first stage (3%, around 10% of CS), which indicated a successful synthesis, well-defined structure, and good thermostability. Adsorption tests of CS-MA-DETA microspheres were performed in Pb(II) and/or Cd(II) solution(s) at various pH values, contact time, and initial concentrations, exhibiting an excellent adsorption capability. Its maximum adsorption capacity calculated by Langmuir model was 239.2 mg Pb(II)/g, or 201.6 mg Cd(II)/g, which was higher than those of most available CS-based adsorbents. Furthermore, several adsorption kinetic and isotherm models were employed to investigate its uptake behavior, implying that it was mainly a monolayer adsorption and chemisorption process. Five-cycle reusability tests demonstrated CS-MA-DETA microspheres could be repeatedly used without significant capacity loss (<10%). Additionally, several potential bonding modes and adsorption sites for both metal ions were also proposed. Overall, CS-MA-DETA microspheres with outstanding adsorption performance toward Pb(II) and/or Cd(II) might serve as a new absorbent for wastewater purification.

  15. Dichlorido(furfuryl-amine-κN)(η-hexa-methyl-benzene)-ruthenium(II).

    PubMed

    Garci, Amine; Thai, Trieu-Tien; Süss-Fink, Georg; Therrien, Bruno

    2011-11-01

    The single-crystal X-ray structure analysis of [RuCl(2)(C(12)H(18))(C(5)H(7)NO)] reveals a distorted piano-stool geometry around the Ru(II) atom, with a hexa-methyl-benzene ligand, two chloride ligands and a furfuryl-amine ligand, the latter coordinating through the amine group. In the crystal, a dimeric structure is observed as a result of N-H⋯Cl inter-actions between two symmetry-related mol-ecules.

  16. 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. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Endothelium-Dependent Relaxation and Angiotensin II Sensitivity in Experimental Preeclampsia

    PubMed Central

    van der Graaf, Anne Marijn; Wiegman, Marjon J.; Plösch, Torsten; Zeeman, Gerda G.; van Buiten, Azuwerus; Henning, Robert H.; Buikema, Hendrik; Faas, Marijke M.

    2013-01-01

    Objective We investigated endothelial dysfunction and the role of angiotensin (Ang)-II type I (AT1-R) and type II (AT2-R) receptor in the changes in the Ang-II sensitivity in experimental preeclampsia in the rat. Methods Aortic rings were isolated from low dose lipopolysaccharide (LPS) infused pregnant rats (experimental preeclampsia; n=9), saline-infused pregnant rats (n=8), and saline (n=8) and LPS (n=8) infused non-pregnant rats. Endothelium-dependent acetylcholine--mediated relaxation was studied in phenylephrine-preconstricted aortic rings in the presence of vehicle, NG-nitro-L-arginine methyl ester and/or indomethacin. To evaluate the role for AT1-R and AT2-R in Ang-II sensitivity, full concentration response curves were obtained for Ang-II in the presence of losartan or PD123319. mRNA expression of the AT1-R and AT2-R, eNOS and iNOS, COX1 and COX2 in aorta were evaluated using real-time RT-PCR. Results The role of vasodilator prostaglandins in the aorta was increased and the role of endothelium-derived hyperpolarizing factor and response of the AT1-R and AT2-R to Ang-II was decreased in pregnant saline infused rats as compared with non-pregnant rats. These changes were not observed during preeclampsia. Conclusion Pregnancy induced adaptations in endothelial function, which were not observed in the rat model for preeclampsia. This role of lack of pregnancy induced endothelial adaptation in the pathophysiology of experimental preeclampsia needs further investigation. PMID:24223202

  18. 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.

  19. 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.

  20. 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.

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

    PubMed

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

    2015-12-19

    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.

  2. Methyl mercury stimulates chain elongation by purified HeLa RNA polymerase II.

    PubMed

    Frenkel, G D; Ducote, J

    1988-11-01

    Methyl mercury (MeHg) inhibited the overall RNA synthetic reaction of HeLa RNA polymerase II. However, when RNA chain initiation was allowed to occur in its absence, MeHg stimulated the rate of the subsequent elongation stage of the reaction. Chain elongation with both double-stranded and single-stranded DNA templates was stimulated. This stimulatory effect was specific for MeHg; both p-hydroxymercuribenzoate and HgCl2 inhibited chain elongation (to about the same degree as they inhibited the overall reaction). The stimulatory effect was also specific for the HeLa polymerase; with Escherichia coli RNA polymerase, MeHg inhibited elongation (to the same degree as it inhibited the overall reaction).

  3. A one-dimensional coordination polymer of 5-[(imidazol-1-yl)methyl]benzene-1,3-dicarboxylic acid with Cu(II) cations.

    PubMed

    Patra, Ranjan; Goldberg, Israel

    2013-04-01

    5-[(Imidazol-1-yl)methyl]benzene-1,3-dicarboxylic acid (H2L) was synthesized and the dimethylformamide- and dimethylacetamide-solvated structures of its adducts with Cu(II), namely catena-poly[[copper(II)-bis[μ-3-carboxy-5-[(imidazol-1-yl)methyl]benzoato

  4. 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.

  5. Syntheses, structures and characterization of isomorphous Co(II) and Ni(II) coordination polymers based on 2-[(1H-imidazol-1-yl)methyl]-6-methyl-1H-benzimidazole and benzene-1,4-dicarboxylate.

    PubMed

    Huang, Qiu Ying; Zhao, Yang; Meng, Xiang Ru

    2017-08-01

    Careful choice of the organic ligands is one of the most important parameters in the rational design and synthesis of coordination polymers. Aromatic polycarboxylates have been widely used in the preparation of metal-organic polymers since they can utilize various coordination modes to form diverse structures and can act as hydrogen-bond acceptors and donors in the assembly of supramolecular structures. Nitrogen-heterocyclic organic compounds have also been used extensively as ligands for the construction of polymers with interesting structures. In the polymers catena-poly[[[diaquabis{2-[(1H-imidazol-1-yl)methyl]-6-methyl-1H-benzimidazole-κN(3)}cobalt(II)]-μ2-benzene-1,4-dicarboxylato-κ(2)O(1):O(4)] dihydrate], {[Co(C8H4O4)(C12H11N4)2(H2O)2]·2H2O}n, (I), and catena-poly[[[diaquabis{2-[(1H-imidazol-1-yl)methyl]-6-methyl-1H-benzimidazole-κN(3)}nickel(II)]-μ2-benzene-1,4-dicarboxylato-κ(2)O(1):O(4)] dihydrate], {[Ni(C8H4O4)(C12H11N4)2(H2O)2]·2H2O}n, (II), the Co(II) or Ni(II) ion lies on an inversion centre and exhibits a slightly distorted octahedral coordination geometry, coordinated by two N atoms from two imidazole rings and four O atoms from two monodentate carboxylate groups and two water molecules. The dicarboxylate ligands bridge metal ions forming a polymeric chain. The 2-[(1H-imidazol-1-yl)methyl]-6-methyl-1H-benzimidazole ligands coordinate to the Co(II) or Ni(II) centres in monodentate modes through an imidazole N atom and are pendant on opposite sides of the main chain. The two structures are isomorphous. In the crystal, the one-dimensional chains are further connected through O-H...O, O-H...N and N-H...O hydrogen bonds, leading to a three-dimensional supramolecular architecture. In addition, the IR spectroscopic properties, PXRD patterns, thermogravimetric behaviours and fluorescence properties of both polymers have been investigated.

  6. 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.

  7. Daphnetin methylation by a novel O-methyltransferase is associated with cold acclimation and photosystem II excitation pressure in rye.

    PubMed

    NDong, Christian; Anzellotti, Dominique; Ibrahim, Ragai K; Huner, Norman P A; Sarhan, Fathey

    2003-02-28

    In plants, O-methylation of phenolic compounds plays an important role in such processes as lignin synthesis, flower pigmentation, chemical defense, and signaling. However, apart from phenylpropanoids and flavonoids, very few enzymes involved in coumarin biosynthesis have been identified. We report here the molecular and biochemical characterization of a gene encoding a novel O-methyltransferase that catalyzes the methylation of 7,8-dihydroxycoumarin, daphnetin. The recombinant protein displayed an exclusive methylation of position 8 of daphnetin. The identity of the methylated product was unambiguously identified as 7-hydroxy-8-methoxycoumarin by co-chromatography on cellulose TLC and coelution from high performance liquid chromatography, with authentic synthetic samples, as well as by UV, mass spectroscopy, (1)H NMR spectral analysis, and NOE correlation signals of the relevant protons. Northern blot analysis and enzyme activity assays revealed that the transcript and corresponding enzyme activity are up-regulated by both low temperature and photosystem II excitation pressure. Using various phenylpropanoid and flavonoid substrates, we demonstrate that cold acclimation of rye leaves increases O-methyltransferase activity not only for daphnetin but also for the lignin precursors, caffeic acid, and 5-hydroxyferulic acid. The significance of this novel enzyme and daphnetin O-methylation is discussed in relation to its putative role in modulating cold acclimation and photosystem II excitation pressure.

  8. Removal of Pb(II) ions by using magnetic chitosan-4-((pyridin-2-ylimino)methyl)benzaldehyde Schiff's base.

    PubMed

    Gutha, Yuvaraja; Munagapati, Venkata Subbaiah

    2016-12-01

    A novel crosslinked magnetic chitosan-4-((pyridin-2-ylimino)methyl)benzaldehyde Schiff's Base (m-CSPIB) was prepared by crosslinking of magnetic iron oxide nanoparticles with chitosan-4-((pyridin-2-ylimino)methyl)benzaldehyde schiff's base and used as an biosorbent for the removal of Pb(II) ions from aqueous environment. The biopolymer has been characterized by XRD, FT-IR, SEM, TEM, (1)H NMR and VSM analysis. Kinetic studies were performed, and the data were fitted well with the pseudo-second-order model. The equilibrium data followed Langmuir isotherm model and the maximum monolayer sorption capacity was found to be 104.16 for Pb(II) ions at 323K. Different thermodynamic parameters namely, change in Gibbs free energy, enthalpy change, and entropy changes were also evaluated from the temperature dependence, and the results suggested that the sorption of Pb(II) onto m-CSPIB was feasible, spontaneous and endothermic in nature.

  9. Enzymatic Cleavage of Type II Restriction Endonucleases on the 2′-O-Methyl Nucleotide and Phosphorothioate Substituted DNA

    PubMed Central

    Zhao, Guojie; Li, Jun; Tong, Zhaoxue; Zhao, Bin; Mu, Runqing; Guan, Yifu

    2013-01-01

    The effects of nucleotide analogue substitution on the cleavage efficiencies of type II restriction endonucleases have been investigated. Six restriction endonucleases (EcoRV, SpeI, XbaI, XhoI, PstI and SphI) were investigated respectively regarding their cleavage when substrates were substituted by 2′-O-methyl nucleotide (2′-OMeN) and phosphorothioate (PS). Substitutions were made in the recognition sequence and the two nucleotides flanking the recognition sequence for each endonuclease. The endonuclease cleavage efficiencies were determined using FRET-based assay. Results demonstrated a position-dependent inhibitory effect of substitution on the cleavage efficiency for all the six endonucleases. In general, the 2′-OMeN substitutions had greater impact than the PS substitutions on the enzymatic activities. Nucleotides of optimal substitutions for protection against RE cleavage were identified. Experimental results and conclusions in this study facilitate our insight into the DNA-protein interactions and the enzymatic cleavage mechanism, particularly for those whose detailed structure information is not available. In addition, the information could benefit the development of bioengineering and synthetic biology. PMID:24260216

  10. Enzymatic cleavage of type II restriction endonucleases on the 2'-O-methyl nucleotide and phosphorothioate substituted DNA.

    PubMed

    Zhao, Guojie; Li, Jun; Tong, Zhaoxue; Zhao, Bin; Mu, Runqing; Guan, Yifu

    2013-01-01

    The effects of nucleotide analogue substitution on the cleavage efficiencies of type II restriction endonucleases have been investigated. Six restriction endonucleases (EcoRV, SpeI, XbaI, XhoI, PstI and SphI) were investigated respectively regarding their cleavage when substrates were substituted by 2'-O-methyl nucleotide (2'-OMeN) and phosphorothioate (PS). Substitutions were made in the recognition sequence and the two nucleotides flanking the recognition sequence for each endonuclease. The endonuclease cleavage efficiencies were determined using FRET-based assay. Results demonstrated a position-dependent inhibitory effect of substitution on the cleavage efficiency for all the six endonucleases. In general, the 2'-OMeN substitutions had greater impact than the PS substitutions on the enzymatic activities. Nucleotides of optimal substitutions for protection against RE cleavage were identified. Experimental results and conclusions in this study facilitate our insight into the DNA-protein interactions and the enzymatic cleavage mechanism, particularly for those whose detailed structure information is not available. In addition, the information could benefit the development of bioengineering and synthetic biology.

  11. 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.

  12. Post-annealing treatment for Cu-TiO2 nanotubes and their use in photocatalytic methyl orange degradation and Pb(II) heavy metal ions removal

    NASA Astrophysics Data System (ADS)

    Sreekantan, Srimala; Mohd Zaki, Syazwani; Lai, Chin Wei; Tzu, Teoh Wah

    2014-07-01

    TiO2 nanotubes were synthesized via electrochemical anodization of Ti foil at 60 V for 1 h in a bath with electrolytes composed of ethylene glycol containing 5 wt.% of NH4F and 1 vol.% of H2O2. The incorporation of optimum Cu2+ ions (1.30 at.%) into TiO2 nanotubes were prepared by using wet impregnation method to improve their photocatalytic methyl orange degradation and Pb(II) heavy metal removal. The small Cu2+ ions were successfully diffused into lattice of TiO2 nanotubes by conducting post-annealing treatment at 400 °C for 4 h in argon atmosphere after wet impregnation. In this manner, optimum Cu2+ ions played a crucial role in suppressing the recombination of charge carriers by forming inter-band states (mismatch of the band energies) within the lattice of Cu-TiO2. The experimental results showed that a maximum of 80% methyl orange removal and 97.3% Pb(II) heavy metal removal at pH 11 under UV irradiation for 5 h. Besides, it was noticed that photocatalytic Pb(II) heavy metal removal was strong dependence on pH of the solution because of the amphoteric character of Cu-TiO2 in an aqueous medium.

  13. Copper(II) complexes with new polypodal ligands presenting axial-equatorial phenoxo bridges {2-[(bis(2-pyridylmethyl)amino)methyl]-4-methylphenol, 2-[(bis(2-pyridylmethyl)amino)methyl]-4-methyl-6-(methylthio)phenol}: examples of ferromagnetically coupled bi- and trinuclear copper(II) complexes.

    PubMed

    Manzur, Jorge; Mora, Hector; Vega, Andrés; Spodine, Evgenia; Venegas-Yazigi, Diego; Garland, María Teresa; El Fallah, M Salah; Escuer, Albert

    2007-08-20

    Two new ligands, 2-[(bis(2-pyridylmethyl)amino)methyl]-4-methylphenol (HL) and 2-[(bis(2-pyridylmethyl)amino)methyl]-4-methyl-6-(methylthio)phenol (HSL), were synthesized and were used to prepare the trinuclear copper(II) complex {[CuSL(Cl)]2Cu}(PF6)2.H2O (1) and the corresponding binuclear complexes [Cu2(SL)2](PF6)2 (2) and [Cu2L2](PF6)2 (3). The crystal structure of 1 shows two different coordination environments: two square base pyramidal centers (Cu1 and Cu1a, related by a C2 axes), acting as ligands of a distorted square planar copper center (Cu2) by means of the sulfur atom of the SCH3 substituent and the bridging phenoxo oxygen atom of the ligand (Cu2-S = 2.294 A). Compounds 2 and 3 show two equivalent distorted square base pyramidal copper(II) centers, bridged in an axial-equatorial fashion by two phenoxo groups, thus defining an asymmetric Cu2O2 core. A long copper-sulfur distance measured in 2 (2.9261(18) A) suggests a weak bonding interaction. This interaction induces a torsion angle between the methylthio group and the phenoxo plane resulting in a dihedral angle of 41.4(5) degrees. A still larger distortion is observed in 1 with a dihedral angle of 74.0(6) degrees. DFT calculations for 1 gave a ferromagnetic exchange between first neighbors interaction, the calculated J value for this interaction being +11.7 cm-1. In addition, an antiferromagnetic exchange for 1 was obtained for the second neighbor interaction with a J value of -0.05 cm-1. The Bleaney-Bowers equation was used to fit the experimental magnetic susceptibility data for 2 and 3; the best fit was obtained with J values of +3.4 and -16.7 cm-1, respectively. DFT calculations for 2 and 3 confirm the nature and the values of the J constants obtained by the fit of the experimental data. ESR and magnetic studies on the reported compounds show a weak exchange interaction between the copper(II) centers. The low values obtained for the coupling constants can be explained in terms of a poor overlap

  14. Biofiltration of methyl tert-butyl ether vapors by cometabolism with pentane: modeling and experimental approach.

    PubMed

    Dupasquier, David; Revah, Sergio; Auria, Richard

    2002-01-15

    Degradation of methyl tert-butyl ether (MTBE) vapors by cometabolism with pentane using a culture of pentane-oxidizing bacteria (Pseudomonas aeruginosa) was studied in a 2.4-L biofilter packed with vermiculite, an inert mineral support. Experimental pentane elimination capacity (EC) of approximately 12 g m(-3) h(-1) was obtained for an empty bed residence time (EBRT) of 1.1 h and inlet concentration of 18.6 g m(-3). For these experimental conditions, EC of MTBE between 0.3 and 1.8 g m(-3) h(-1) were measured with inlet MTBE concentration ranging from 1.1 to 12.3 g m(-3). The process was modeled with general mass balance equations that consider a kinetic model describing cross-competitive inhibition between MTBE (cosubstrate) and pentane (substrate). The experimental data of pentane and MTBE removal efficiencies were compared to the theoretical predictions of the model. The predicted pentane and MTBE concentration profiles agreed with the experimental data for steady-state operation. Inhibition by MTBE of the pentane EC was demonstrated. Increasing the inlet pentane concentration improved the EC of MTBE but did not significantly change the EC of pentane. MTBE degradation rates obtained in this study were much lower than those using consortia or pure strains that can mineralize MTBE. Nevertheless, the system can be improved by increasing the active biomass.

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

    PubMed Central

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

    2009-01-01

    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. PMID:19635855

  16. 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.

  17. Ancestry-Specific Methylation Patterns in Admixed Offspring from an Experimental Coyote and Gray Wolf Cross.

    PubMed

    vonHoldt, Bridgett; Heppenheimer, Elizabeth; Petrenko, Vladimir; Croonquist, Paula; Rutledge, Linda Y

    2017-06-01

    Reduced fitness of admixed individuals is typically attributed to genetic incompatibilities. Although mismatched genomes can lead to fitness changes, in some cases the reduction in hybrid fitness is subtle. The potential role of transcriptional regulation in admixed genomes could provide a mechanistic explanation for these discrepancies, but evidence is lacking for nonmodel organisms. Here, we explored the intersection of genetics and gene regulation in admixed genomes derived from an experimental cross between a western gray wolf and western coyote. We found a significant positive association between methylation and wolf ancestry, and identified outlier genes that have been previously implicated in inbreeding-related, or otherwise deleterious, phenotypes. We describe a pattern of site-specific, rather than genome-wide, methylation driven by inter-specific hybridization. Epigenetic variation is thus suggested to play a nontrivial role in both maintaining and combating mismatched genotypes through putative transcriptional mechanisms. We conclude that the regulation of gene expression is an underappreciated key component of hybrid genome functioning, but could also act as a potential source of novel and beneficial adaptive variation in hybrid offspring. © The American Genetic Association 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  18. 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.

  19. Interaction between methyl glyoxal and ascorbic acid: experimental and theoretical aspects

    NASA Astrophysics Data System (ADS)

    Banerjee, D.; Koll, A.; Filarowski, A.; Bhattacharyya, S. P.; Mukherjee, S.

    2004-06-01

    The absorption spectral change of methyl glyoxal (MG) due to the interaction with ascorbic acid (AA or Vitamin C) has been investigated using steady-state spectroscopic technique. A plausible explanation for the spectral change has been discussed on the basis of hydrogen bonding interaction between the two interacting species. The equilibrium constant for the complex formation due to hydrogen bonding interaction between MG and AA has been obtained from absorption spectral changes. Ab inito calculations with DFT B3LYP/6/31G (d,p) basis sets have been used to find out the molecular structure of the hydrogen bonded complex. The O⋯H distance found in the OH⋯O hydrogen bond turns out to be quite short (1.974 Å) which is in conformity with the large value of the equilibrium constant determined experimentally.

  20. 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).

  1. Screening for catalytically active Type II restriction endonucleases using segregation-induced methylation deficiency

    PubMed Central

    Ukanis, Mindaugas; Sapranauskas, Rimantas; Lubys, Arvydas

    2012-01-01

    Type II restriction endonucleases (REases) are one of the basic tools of recombinant DNA technology. They also serve as models for elucidation of mechanisms for both site-specific DNA recognition and cleavage by proteins. However, isolation of catalytically active mutants from their libraries is challenging due to the toxicity of REases in the absence of protecting methylation, and techniques explored so far had limited success. Here, we present an improved SOS induction-based approach for in vivo screening of active REases, which we used to isolate a set of active variants of the catalytic mutant, Cfr10IE204Q. Detailed characterization of plasmids from 64 colonies screened from the library of ∼200 000 transformants revealed 29 variants of cfr10IR gene at the level of nucleotide sequence and 15 variants at the level of amino acid sequence, all of which were able to induce SOS response. Specific activity measurements of affinity-purified mutants revealed >200-fold variance among them, ranging from 100% (wild-type isolates) to 0.5% (S188C mutant), suggesting that the technique is equally suited for screening of mutants possessing high or low activity and confirming that it may be applied for identification of residues playing a role in catalysis. PMID:22753027

  2. Group II metabotropic glutamate receptors modify N-methyl-D-aspartate receptors via Src kinase

    PubMed Central

    Trepanier, Catherine; Lei, Gang; Xie, Yu-Feng; MacDonald, John F.

    2013-01-01

    Group II metabotropic glutamate receptors (mGluR2/3) have emerged as important targets for the treatment of schizophrenia. Since hypofunction of N-methyl-D-aspartate receptors (NMDARs) has also been implicated in the etiology of schizophrenia, we examined whether postsynaptic mGluR2/3 regulate NMDAR function. Activation of mGluR2/3 significantly decreased the ratio of AMPA-to-NMDA excitatory postsynaptic currents at Schaffer Collateral-CA1 synapses and enhanced the peak of NMDA-evoked currents in acutely isolated CA1 neurons. The mGluR2/3-mediated potentiation of NMDAR currents was selective for GluN2A-containing NMDARs and was mediated by the Src family kinase Src. Activation of mGluR2/3 inhibited the adenylyl cyclase-cAMP-PKA pathway and thereby activated Src by inhibiting its regulatory C-terminal Src kinase (Csk). We suggest a novel model of regulation of NMDARs by Gi/o-coupled receptors whereby inhibition of the cAMP-PKA pathway via mGluR2/3 activates Src kinase and potentiates GluN2A-containing NMDAR currents. This represents a potentially novel mechanism to correct the hypoglutamatergic state found in schizophrenia. PMID:23378895

  3. 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.

  4. Experimental and modelling study of methyl oleate pyrolysis between 500 and 650 circC

    NASA Astrophysics Data System (ADS)

    Archambault, D.; Billaud, F.

    1999-05-01

    This paper describes an experimental and modelling study of methyl oleate pyrolysis in a tubular flow reactor at atmospheric pressure. The reaction temperatures ranged from 500 to 650 circC. The residence times were 230, 350, 500 and 600 ms. The proposed radical mechanism describes qualitatively all experimental observed species. This mechanism displays a satisfactory agreement between experimental and simulated values of molar fractions of pyrolysis reaction products. Cet article décrit une étude expérimentale et mécanistique de la pyrolyse de l'oléate de méthyle dans un réacteur tubulaire à pression atmosphérique. La température de réaction varie entre 500 et 650 circC. Les temps de passage étudiés sont 230, 350, 500 et 600 ms. Le mécanisme radicalaire proposé rend compte qualitativement de toutes les espèces observées expérimentalement. Ce mécanisme donne un bon accord entre les valeurs expérimentales et simulées des fractions molaires des produits de la réaction de pyrolyse.

  5. Experimental and theoretical study on a new copper(II) complex derived from pyridoxal hydrochloride and 1,2-diaminocyclohexane

    NASA Astrophysics Data System (ADS)

    Mandal, Senjuti; Sikdar, Yeasin; Sanyal, Ria; Goswami, Sanchita

    2017-01-01

    In this work, guided by a pyridoxal derived Schiff base ligand, H2PydChda [5-Hydroxymethyl-4-({2-[5-hydroxymethyl-2-methylpyridin-3-hydroxy-4-ylethylene)-amino]-cyclohexylimino}-methyl)-2-methylpyridin-3-ol], a new copper(II) complex, [Cu(PydChda-2H+)]2·4ClO4·2H2O was constructed and structurally characterized by single crystal X-ray diffraction study. DFT calculations further substantiate the experimental features. Additionally, experiments were performed to demonstrate the accessibility to any enzymatic activity and the complex provides positive response for phosphatase activity towards 4-NPP substrate.

  6. Overview of the Pegasus-II experimental program

    SciTech Connect

    Shlachter, J.S.; Adams, P.J.; Atchison, W.L.

    1998-12-31

    Pegasus-II is a pulsed power facility at Los Alamos National Laboratory which is used to conduct a variety of experiments in the high energy density regime, with applications to the physics of nuclear weapons as well as basic science. The chief mission of the facility is the systematic investigation of hydrodynamic physics issues through the use of a magnetically-driven, cylindrical imploding liner. At 4.3-MJ of stored energy, Pegasus-II is one of the largest capacitor-bank facilities in the world. Peak currents as high as 12 MA have been produced with a quarter-cycle time of 6--8 {micro}s. The active portion of the standardized aluminum liner is a 3.2-g right hollow cylinder designed such that the inner surface of the liner remains at solid aluminum density during the course of the experiment. The run-in time for a typical experiment is {approximately}10 {micro}s. For some experiments, a diagnostic package is placed inside the liner to analyze physical processes associated with multi-microsecond convergent implosions of macroscopic solid shells. These campaigns include the study of instability growth rates, hydrodynamic bounce and mix, and mechanical heating associated with high strain and strain rate. Other experimental studies, in particular those examining the shock /production of ejecta and shock-driven hydrodynamic vortex formation and compression, have involved the use of an internal target package. By varying the Pegasus-II operating conditions, the impact of the liner on an internal target of a few cm diameter results in shock pressures of 100kBar--1MBar with liner velocities of 3 mm/{micro}s--10 mm/{micro}s. Some experiments have been conducted in the regime where strength of materials affects the hydrodynamical behavior of the system, while for other target designs, efforts have been made to minimize the role of material strength. Hydrodynamic experiments on Pegasus-II uniquely combine convergent geometry with axial diagnostic access of macroscopic

  7. 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

  8. 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.

  9. Synthesis and characterization of cobalt(II), nickel(II), copper(II) and zinc(II) complexes with Schiff base derived from 4-amino-3-mercapto-6-methyl-5-oxo-1,2,4-triazine.

    PubMed

    Singh, Kiran; Barwa, Manjeet Singh; Tyagi, Parikshit

    2007-03-01

    A few (1:1) and (1:2) metal complexes of cobalt(II), nickel(II), copper(II) and zinc(II) have been isolated with ligand derived from the condensation of 4-amino-3-mercapto-6-methyl-5-oxo-1,2,4-triazine with 2-acetylpyridine (L(1)) and characterized by elemental analysis, conductivity measurements, infrared, electronic, (1)H NMR spectral data, magnetic and thermogravimetric analyses. Due to insolubility in water and most of the common organic solvents and infusibility at higher temperatures, all the complexes are thought to be polymeric in nature. A square-planar geometry was suggested for copper(II) and octahedral proposed for cobalt(II), nickel(II) and zinc(II). Some of the chemically synthesized compounds have been screened in vitro against the three Gram-positive (Staphylococcus aureus, Staphylococcus epidermidis and Bacillus subtilis) and two Gram-negative (Salmonella typhi and Escherichia coli) organisms. It is observed that the coordination of metal ion has pronounced effect on the microbial activities of the ligand. The metal complexes have higher antimicrobial effect than the free ligands.

  10. Reaction of alkylphenols with acetals. II. Reaction of 4methyl-2-tert-butylphenol with dimethoxymethane

    SciTech Connect

    Starikova, O.F.; Gurvich, Y.A.; Kumok, S.T.; Styskin, E.L.

    1985-12-20

    The authors explain how di(hydroxydialkylaryl) derivatives of methane play an important role in the inhibition of oxidation processes in polymers, oils, fuels, and other organic materials. They investigate the reaction of 4-methyl-2-tert-butylphenol with dimethoxymethane, and established that the reaction mass contained 2-methoxymethyl-4-6-tert-butylphenol. The formation and the transformations of 2-methoxymethyl-4-methyl-6-tert-butylphenol do not have a significant effect on the synthesis of di(2-hydroxy-5-methyl-3-tert-butylphenyl) methane from 4-methyl-2-tert-butyl-phenol and dimethoxymethane.

  11. Experimental and computational studies on zwitterionic (E)-1-((4-phenoxyphenyliminio)methyl)naphthalen-2-olate

    NASA Astrophysics Data System (ADS)

    Alpaslan, Gökhan; Macit, Mustafa; Erdönmez, Ahmet; Büyükgüngör, Orhan

    2011-06-01

    The Schiff base compound (E)-1-((4-phenoxyphenyliminio)methyl)naphthalen-2-olate has been synthesized and characterized by IR, UV-Vis, and X-ray single-crystal determination. Molecular geometry of the title compound in the ground state have been calculated using the density functional method (DFT) with 6-31G(d,p) basis set and compared with the experimental data. The calculated results show that the optimized geometry can well reproduce the crystal structure. By using TD-DFT method, electronic absorption spectra of the title compound have been predicted and a good agreement with the TD-DFT method and the experimental ones is determined. Molecular orbital coefficient analyses reveal that the electronic transitions are mainly assigned to n → p∗ and p → p∗ electronic transitions. To investigate the tautomeric stability, optimization calculations at B3LYP/6-31G(d,p) level were performed for the NH and OH forms of the title compound. Calculated results reveal that the OH form is more stable than NH form. In addition, molecular electrostatic potential and non-linear optical properties of the title compound were performed at B3LYP/6-31G(d,p) level of theory.

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

    PubMed

    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.

  13. 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.

  14. 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.

  15. 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 ...

  16. 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 ...

  17. 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. © 2013 German Botanical Society and The Royal Botanical Society of the Netherlands.

  18. trans-Dichlorido­tetra­kis­[(di­methyl­phosphor­yl)methanaminium-κO]cobalt(II) tetra­chloridocobaltate(II)

    PubMed Central

    Reiss, Guido J.

    2013-01-01

    The asymmetric unit of the title structure, [CoCl2(C3H11NOP)4][CoCl4]2, consists of one half of the trans-dichlorido­tetra­kis­[(di­methyl­phosphor­yl)methanaminium]cobalt(II) tetra­cation lying on an inversion center and one tetra­chloridocobaltate(II) dianion on a general position. Four O-coordinated cationic (di­methyl­phosphor­yl)methanaminium (dpmaH+) ligands occupy the equatorial coordination sites, whereas the chloride ligands occupy axial positions of the roughly o­cta­hedral coordination polyhedron of the cobalt metal center. Intra­molecular hydrogen bonds between the aminium groups and the O atom of the phosphoryl groups and additional hydrogen bonds between the aminium groups and the chloride ligands are present. Furthermore, four of the six H atoms not involved in intra­molecular bonding of each cobalt(II) tetra­cation form weak hydrogen bonds to four adjacent tetra­chloridocobaltate(II) counter-anions. By these inter­molecular hydrogen bonds, one-dimensional polymeric strands are formed along the b-axis direction. The hydrogen bonding is analyzed using the graph-set method and the structural similarity with dpmaHCl is discussed. PMID:23723763

  19. Synthesis and characterization of bis-(2-cyano-1-methyl-3-{2- {{(5-methylimidazol-4-yl)methyl}thio}ethyl)guanidine copper(II) sulfate tetrahydrate

    NASA Astrophysics Data System (ADS)

    Rahardjo, Sentot B.; Endah Saraswati, Teguh; Pramono, Edy; Fitriana, Nur

    2016-02-01

    Complex of copper(II) with 2-cyano-1-methyl-3-{2-{{(5-methylimidazol-4- yl)methyl}thio}ethyl)guanidin(xepamet) had been synthesized in 1 : 4 mole ratio of metal to the ligand in methanol. The complex was characterized by metal analysis, thermal gravimetry/differential thermal analyzer (TG/DTA), molar conductivity meter, (Fourier transform infrared spectroscopy) FT-IR, UV-Vis spectroscopy, and magnetic susceptibility balance. The molar conductivity measurement shows that the complex was 2: 1 for electrolyte and SO42- which was acting as a counter ion. The thermal analysis by Thermogravimetric (TG) indicates that the complex contained four molecules of H2O. The Infrared spectral data indicates that functional groups of (C=N) imidazole and (C-S) are coordinated to the center ion Cu2+. Magnetic moment measurement shows that the complex is paramagnetic with peff = 1.78 ± 0.01 BM. Electronic spectra of the complex show a broad band at 608 nm (16447.23 cm-1) are due to Eg→T2g transition. Based on those of characteristics, The complex formula was estimated as [Cu(xepamet)2]SO4.4H2O. The structure of [Cu(xepamet)2]SO4.4H2O complex is probably square planar.

  20. Four Ni(II) complexes with the new cyclam-methylimidazole ligand 1-[(1-methyl-1H-imidazol-2-yl)methyl]-1,4,8,11-tetraazacyclotetradecane.

    PubMed

    De Candia, Ariel G; Molnar, Matias; Slep, Leonardo D; Baggio, Ricardo

    2012-05-01

    Although it has not proved possible to crystallize the newly prepared cyclam-methylimidazole ligand 1-[(1-methyl-1H-imidazol-2-yl)methyl]-1,4,8,11-tetraazacyclotetradecane (L(Im1)), the trans and cis isomers of an Ni(II) complex, namely trans-aqua{1-[(1-methyl-1H-imidazol-2-yl)methyl]-1,4,8,11-tetraazacyclotetradecane}nickel(II) bis(perchlorate) monohydrate, [Ni(C(15)H(30)N(6))(H(2)O)](ClO(4))(2)·H(2)O, (1), and cis-aqua{1-[(1-methyl-1H-imidazol-2-yl)methyl]-1,4,8,11-tetraazacyclotetradecane}nickel(II) bis(perchlorate), [Ni(C(15)H(30)N(6))(H(2)O)](ClO(4))(2), (2), have been prepared and structurally characterized. At different stages of the crystallization and thermal treatment from which (1) and (2) were obtained, a further two compounds were isolated in crystalline form and their structures also analysed, namely trans-{1-[(1-methyl-1H-imidazol-2-yl)methyl]-1,4,8,11-tetraazacyclotetradecane}(perchlorato)nickel(II) perchlorate, [Ni(ClO(4))(C(15)H(30)N(6))]ClO(4), (3), and cis-{1,8-bis[(1-methyl-1H-imidazol-2-yl)methyl]-1,4,8,11-tetraazacyclotetradecane}nickel(II) bis(perchlorate) 0.24-hydrate, [Ni(C(20)H(36)N(6))](ClO(4))(2)·0.24H(2)O, (4); the 1,8-bis[(1-methyl-1H-imidazol-2-yl)methyl]-1,4,8,11-tetraazacyclotetradecane ligand is a minor side product, probably formed in trace amounts in the synthesis of L(Im1). The configurations of the cyclam macrocycles in the complexes have been analysed and the structures are compared with analogues from the literature.

  1. 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

  2. Methylation of WNT target genes AXIN2 and DKK1 as robust biomarkers for recurrence prediction in stage II colon cancer.

    PubMed

    Kandimalla, R; Linnekamp, J F; van Hooff, S; Castells, A; Llor, X; Andreu, M; Jover, R; Goel, A; Medema, J P

    2017-04-03

    Stage II colon cancer (CC) still remains a clinical challenge with patient stratification for adjuvant therapy (AT) largely relying on clinical parameters. Prognostic biomarkers are urgently needed for better stratification. Previously, we have shown that WNT target genes AXIN2, DKK1, APCDD1, ASCL2 and LGR5 are silenced by DNA methylation and could serve as prognostic markers in stage II CC patients using methylation-specific PCR. Here, we have extended our discovery cohort AMC90-AJCC-II (N=65) and methylation was analyzed by quantitative pyrosequencing. Subsequently, we validated the results in an independent EPICOLON1 CC cohort (N=79). Methylation of WNT target genes is negatively correlated to mRNA expression. A combination of AXIN2 and DKK1 methylation significantly predicted recurrences in univariate (area under the curve (AUC)=0.83, confidence interval (CI): 0.72-0.94, P<0.0001) analysis in stage II microsatellite stable (MSS) CC patients. This two marker combination showed an AUC of 0.80 (CI: 0.68-0.91, P<0.0001) in the EPICOLON1 validation cohort. Multivariate analysis in the Academic Medical Center (AMC) cohort revealed that both WNT target gene methylation and consensus molecular subtype 4 (CMS4) are significantly associated with poor recurrence-free survival (hazard ratio (HR)methylation: 3.84, 95% CI: 1.14-12.43; HRCMS4: 3.73, 95% CI: 1.22-11.48). CMS4 subtype tumors with WNT target methylation showed worse prognosis. Combining WNT target gene methylation and CMS4 subtype lead to an AUC of 0.89 (0.791-0.982, P<0.0001) for recurrence prediction. Notably, we observed that methylation of DKK1 is high in BRAF mutant and CIMP (CpG island methylator phenotype)-positive cancers, whereas AXIN2 methylation appears to be associated with CMS4. Methylation of AXIN2 and DKK1 were found to be robust markers for recurrence prediction in stage II MSS CC patients. Further validation of these findings in a randomized and prospective manner could pave a way to identify

  3. A comparison of the rates of methylation of mercury(II) species in aquatic media by various organotin and organosilicon moieties.

    PubMed

    Bellama, J M; Jewett, K L; Manders, W F; Nies, J D

    1988-07-01

    Metals can be methylated in environmental aqueous media by a variety of organotin and organosilicon compounds. Main group metals and metalloids were surveyed for the identification of species that can either donate or accept methyl groups. The methylation of mercury(II) by trimethyltin cation was found to be a bimolecular reaction, the reaction rate of which decreased with increasing chloride concentration. Kinetic investigations using NMR techniques showed that the most important pairs of reactants were (CH3)3Sn+ + HgCl2, (CH3)3SnCl + HgCl2, and (CH3)3SnCl + HgCl-3. Sodium 2,2,3,3-tetradeutero-3-(trimethylsilyl)propionate (TSP) and sodium 2,2-dimethyl-2-silapentane-5-sulfonate (DSS) were found to methylate mercury(II). Organylsilatranes were found to transfer their organic groups readily to mercury(II) to produce organomercury compounds.

  4. Crystal structure of di-aqua-bis-(2,6-di-methyl-pyrazine-κN)bis-(thio-cyanato-κN)cobalt(II) 2,5-di-methyl-pyrazine tris-olvate.

    PubMed

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

    2015-12-01

    In the crystal structure of the title compound, [Co(NCS)2(C6H8N2)2(H2O)2]·3C6H8N2, the Co(II) cation is coordinated by two terminally N-bound thio-cyanate anions, two water mol-ecules and two 2,6-di-methyl-pyrazine ligands, forming a discrete complex with a slightly distorted octa-hedral N4O2 coordination environment. The asymmetric unit contains one Co(II) cation and three halves of 2,5-di-methyl-pyrazine solvate mol-ecules, all entities being completed by inversion symmetry, as well as one thio-cyanate anion, an aqua ligand and a 2,6-di-methyl-pyrazine ligand, all in general positions. In the crystal, discrete complexes are arranged in a way that cavities are formed where the noncoordinating 2,5-di-methyl-pyrazine mol-ecules are located. The coordination of the latter to the metal is prevented due to the bulky methyl groups in vicinal positions to the N atoms, leading to a preferential coordination through the 2,6-di-methyl-pyrazine ligands. The complex mol-ecules are linked by O-H⋯N hydrogen bonds between the water H atoms and the N atoms of 2,5-di-methyl-pyrazine solvent mol-ecules, leading to a layered structure extending parallel to (100).

  5. 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.

  6. Experimental Investigations on Diesel engine using Methyl esters of Jatropha oil and fish oil

    NASA Astrophysics Data System (ADS)

    Karthikeyan, A.; Jayaprabakar, J.; Dude Williams, Richard

    2017-05-01

    The aim of the study is to use fish oil methyl ester (FME) and Jatropha oil methyl ester (JME) as a substitute for diesel in compression ignition engine. Experiments were conducted when the engine was fuelled with Diesel, Fish oil methyl ester and Jatropha oil methyl ester. The experiment covered a range of loads. An AVL smoke meter was used to measure the smoke density in HSU (Hatridge Smoke Unit). The exhaust emissions were measured using exhaust gas analyzer. High volume sampler was employed to measure the particulate matter in exhaust. The performance of the engine was evaluated in terms of brake specific fuel consumption, brake thermal efficiency. The combustion characteristics of the engine were studied in terms of cylinder pressure with respect to crank angle. The emissions of the engine were studied in terms of concentration of CO, NOx, particulate matter and smoke density. The results obtained for Fish oil methyl ester, Jatropha oil methyl ester, were compared with the results of diesel. Bio-diesel, which can be used as an alternate diesel fuel, is made from vegetable oil and animal fats. It is renewable, non-toxic and possesses low emission profiles.

  7. Crystal structure of di-aqua-bis-(2,6-di-methyl-pyrazine-κN (4))bis-(thio-cyanato-κN)cobalt(II) 2,5-di-methyl-pyrazine monosolvate.

    PubMed

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

    2015-12-01

    In the crystal structure of the title compound, [Co(NCS)2(C6H8N2)2(H2O)2]·C6H8N2, the Co(II) cation is coordinated by the N atoms of two terminal thio-cyanate anions, the O atoms of two water mol-ecules and two N atoms of two 2,6-di-methyl-pyrazine ligands. The coordination sphere of the resulting discrete complex is that of a slightly distorted octa-hedron. The asymmetric unit comprises a Co(II) cation and half of a 2,5-di-methyl-pyrazine ligand, both of which are located on centres of inversion, and a water ligand, a 2,6-di--methyl-pyrazine ligand and one thio-cyanate anion in general positions. In the crystal, the discrete complexes are arranged in such a way that cavities are formed in which the 2,5-di-methyl-pyrazine solvent mol-ecules are located. The coordination of the 2,5-di-methyl-pyrazine mol-ecules to the metal is apparently hindered due to the bulky methyl groups in vicinal positions to the N atoms, leading to a preferential coordination of the 2,6-di-methyl-pyrazine ligands. The discrete complexes are linked by O-H⋯N hydrogen bonds between one water H atom and the non-coordinating N atom of the 2,6-di-methyl-pyrazine ligands. The remaining water H atom is hydrogen bonded to one N atom of the 2,5-di-methyl-pyrazine solvent mol-ecule. This arrangement leads to the formation of a two-dimensional network extending parallel to (010).

  8. Nuclear War Media and Firebreaks II: An Experimental Study.

    ERIC Educational Resources Information Center

    Mayton, Daniel M., II

    Ground Zero is an organization whose intent is to provide factual information on nuclear war issues. Ground Zero has published a simulation called "Firebreaks II: A War-Peace Game" about the ways nuclear war might be prevented. The impact of Firebreaks II on college students' attitudes was assessed in 79 student volunteers of whom 40…

  9. 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.

  10. 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.

  11. 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 ...

  12. 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...

  13. 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 ...

  14. Effects of ionizing radiation on DNA methylation: from experimental biology to clinical applications.

    PubMed

    Miousse, Isabelle R; Kutanzi, Kristy R; Koturbash, Igor

    2017-05-01

    Ionizing radiation (IR) is a ubiquitous environmental stressor with genotoxic and epigenotoxic capabilities. Terrestrial IR, predominantly a low-linear energy transfer (LET) radiation, is being widely utilized in medicine, as well as in multiple industrial applications. Additionally, an interest in understanding the effects of high-LET irradiation is emerging due to the potential of exposure during space missions and the growing utilization of high-LET radiation in medicine. In this review, we summarize the current knowledge of the effects of IR on DNA methylation, a key epigenetic mechanism regulating the expression of genetic information. We discuss global, repetitive elements and gene-specific DNA methylation in light of exposure to high and low doses of high- or low-LET IR, fractionated IR exposure, and bystander effects. Finally, we describe the mechanisms of IR-induced alterations to DNA methylation and discuss ways in which that understanding can be applied clinically, including utilization of DNA methylation as a predictor of response to radiotherapy and in the manipulation of DNA methylation patterns for tumor radiosensitization.

  15. 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.

  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. 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.

  19. Poly(methyl methacrylate)-cellulose nitrate copolymers. II. Physical and mechanical properties

    SciTech Connect

    Badran, B.M.; Sherif, S.; El-Sheltawi, S.T.; Abu-Sedira, A.A.

    1981-03-01

    Poly(methyl methacrylate)-cellulose nitrate copolymers were prepared by bulk polymerization using benzoyl peroxide as initiator. Cellulose nitrates of two different nitrogen contents (11.4 and 12.2%) were used. The prepared copolymers were ..gamma..-irradiated for specified periods of up to 11.83 Mrad. Their physical and mechanical properties were measured before and after irradiation. The title copolymers showed lower modulus, tensile strength, and elongation at break than poly(methyl methacrylate) itself, but they showed better hardness and abrasian. Irradiation of up to 6.57 Mrad improved the modulus of the copolymers. Hardness and abrasion were improved by increasing cellulose nitrate content. The prepared copolymers that contained cellulose nitrate of 11.4% nitrogen showed secondary transition points. The increase of cellulose nitrate concentration shifted both first and second transition points to relatively higher values.

  20. Pd(II) complexes based on quinoline derivative: structural characterization and their role as a catalyst for hydrogenation of (E)-1-methyl-4-(2-nitrovinyl)benzene.

    PubMed

    Azam, Mohammad; Islam, Mohammad Shahidul; Al-Resayes, Saud I; Rafiq Siddiqui, M; Trzesowska-Kruszynska, Agata; Kruszynski, Rafal

    2014-04-05

    A series of two new Pd(II) complexes with ligand, HL, (z)-2-((quinolin-3-ylimino)methyl)phenol, derived from 3-aminoquinoline and 2-hydroxybenzaldehyde was reported. The structure of ligand, HL was determined by single crystal X-ray diffraction. The ligand, HL crystallizes in the space group P21/n of the monoclinic system with unit cell dimensions a=8.8733(8), b=6.3318(5), c=11.5145(9). The reaction of ligand, HL with PdX2 [X=Cl(-), OAc] in 2:1molar ratio yielded complexes of the type [Pd(HL)2X2] [X=Cl(-), OAc]. The ligand, HL and its Pd(II) complexes were characterized by various physico-chemical techniques; elemental analyses, ionization mass spectrometry (ESI-MS), UV/Vis, FT-IR, (1)H and (13)C NMR spectroscopy. UV/Vis absorption studies showed a square planar geometry around Pd (II) ion. The selective hydrogenation of (E)-1-methyl-4-(2-nitrovinyl)benzene in ethanol using synthesized Pd(II) complexes as catalysts was investigated at room temperature. The Pd(II) complexes catalyzed the hydrogenation of (E)-1-methyl-4-(2-nitrovinyl)benzene to (E)-1-methyl-4-(2-aminovinyl) benzene. Furthermore, the catalytic activity increased with increasing the quantity of Pd(II) complexes as catalysts. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. The electrochemical detection of Ru(II) in a methyl methacrylate solution.

    PubMed

    De Wael, Karolien; Adriaens, Annemie; Temmerman, Eduard

    2006-02-15

    This article describes the voltammetric behaviour of RuCl(2)(PPh(3))(3) in a methyl methacrylate (MMA) solution. Acquiring this type of information is only possible when the ohmic resistance can be kept sufficiently low. Therefore, the conductivity study of pure methyl methacrylate and a tetrabutylammonium tetrafluoroborate (TBABF(4)) methyl methacrylate solution has been described as well. Impedance measurements show an increase in conductivity by adding TBABF(4), while a conductometric curve illustrates the presence of ion pairs, triple ions and quadrupoles depending on the TBABF(4) concentration. The conductivity of a 0.1molL(-1) TBABF(4)-MMA solution (formation of charged triple ions) was high enough to perform electrochemical experiments and a calibration curve could be obtained. The ability of obtaining relevant electrochemical data in low conducting media opens up new perspectives, especially for electroanalytical purposes used to monitor polymer reactions, more specific atom transfer radical polymerization (ATRP) reactions. This method employs a redox process with transition metal complexes in which a halogen ion is transferred reversibly between the transition metal and the polymer chain end. The dynamic equilibrium can be monitored by measuring the ruthenium concentration.

  2. Kinetics of the methylation of a platinum(II) diimine dithiolate complex

    SciTech Connect

    Stace, Justin J.; Ball, P. J.; Shingade, Vikas; Chatterjee, Sayandev; Shiveley, Amber; Fleeman, Wendi L.; Staniszewski, Aaron J.; Krause, Jeanette A.; Connick, William B.

    2016-06-01

    Pt(dbbpy)(bdt) and Pt(tmphen)(bdt) (dbbpy = 4,4'-di-t-butyl-2,2'-bipyridine; tmphen = 3,4,7,8-tetramethyl-1,10-phenanthroline; bdt2- = 1,2-benzenedithiolate) are reported. Pt(dbbpy)(bdt) reacts with one equivalent of methyl iodide to give the S-methylated product, [Pt(dbbpy)(CH3bdt)]I. The reaction follows second order kinetics with a rate constant of 1.3×10 2 M-1s-1 at 311 K. The accumulated data are consistent with direct nucleophilic attack by the coordinated bdt2- ligand sulfur atom on the carbon atom of the methyl iodide. Variable-temperature experiments yield an Arrhenius activation energy of 51 ± 3 kJ/mol. Activated complex reaction theory yields an enthalpy and entropy of activation of 48 ± 2 kJ/mol and 125 ± 7 J/(mol K), respectively, consistent with an SN2 reaction mechanism. The structure of the monosulfinate adduct, Pt(dbbpy)(bdtO2), also is reported. The fluid-solution luminescence of Pt(tmphen)(bdt) is concentration dependent and characterized by a 1591 ± 41 ns lifetime and 2.6 ± 0.2% quantum yield at infinite dilution.

  3. A histone arginine methylation localizes to nucleosomes in satellite II and III DNA sequences in the human genome.

    PubMed

    Capurso, Daniel; Xiong, Hao; Segal, Mark R

    2012-11-15

    Applying supervised learning/classification techniques to epigenomic data may reveal properties that differentiate histone modifications. Previous analyses sought to classify nucleosomes containing histone H2A/H4 arginine 3 symmetric dimethylation (H2A/H4R3me2s) or H2A.Z using human CD4+ T-cell chromatin immunoprecipitation sequencing (ChIP-Seq) data. However, these efforts only achieved modest accuracy with limited biological interpretation. Here, we investigate the impact of using appropriate data pre-processing -deduplication, normalization, and position- (peak-) finding to identify stable nucleosome positions - in conjunction with advanced classification algorithms, notably discriminatory motif feature selection and random forests. Performance assessments are based on accuracy and interpretative yield. We achieved dramatically improved accuracy using histone modification features (99.0%; previous attempts, 68.3%) and DNA sequence features (94.1%; previous attempts, <60%). Furthermore, the algorithms elicited interpretable features that withstand permutation testing, including: the histone modifications H4K20me3 and H3K9me3, which are components of heterochromatin; and the motif TCCATT, which is part of the consensus sequence of satellite II and III DNA. Downstream analysis demonstrates that satellite II and III DNA in the human genome is occupied by stable nucleosomes containing H2A/H4R3me2s, H4K20me3, and/or H3K9me3, but not 18 other histone methylations. These results are consistent with the recent biochemical finding that H4R3me2s provides a binding site for the DNA methyltransferase (Dnmt3a) that methylates satellite II and III DNA. Classification algorithms applied to appropriately pre-processed ChIP-Seq data can accurately discriminate between histone modifications. Algorithms that facilitate interpretation, such as discriminatory motif feature selection, have the added potential to impart information about underlying biological mechanism.

  4. 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

  5. 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

  6. Power and power-to-flow reactivity transfer functions in EBR-II (Experimental Breeder Reactor II) fuel

    SciTech Connect

    Grimm, K.N.; Meneghetti, D. )

    1989-11-01

    Reactivity transfer functions are important in determining the reactivity history during a power transient. Overall nodal transfer functions have been calculated for different subassembly types in the Experimental Breeder Reactor II (EBR-II). Steady-state calculations for temperature changes and, hence, reactivities for power changes have been separated into power and power-to-flow-dependent terms. Axial nodal transfer functions separated into power and power-to-flow-dependent components are reported in this paper for a typical EBR-II fuel pin. This provides an improved understanding of the time dependence of these components in transient situations.

  7. 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

  8. Significance of the methyl group on the oxazine ring of ofloxacin derivatives in the inhibition of bacterial and mammalian type II topoisomerases.

    PubMed Central

    Hoshino, K; Sato, K; Akahane, K; Yoshida, A; Hayakawa, I; Sato, M; Une, T; Osada, Y

    1991-01-01

    A study was made of the correlation between the in vitro inhibitory effects of several quinolones, including four ofloxacin derivatives, on bacterial DNA gyrase from Escherichia coli KL-16 and on topoisomerase II from fetal calf thymus. No correlation was observed between the inhibitions of DNA gyrase activity and topoisomerase II activity. On the other hand, the inhibitory effects of these quinolones against topoisomerase II were closely correlated with their inhibition of cell growth. Furthermore, among the oxazine derivatives tested, the derivative with a methyl group at position 3 in an S configuration showed the highest activity against DNA gyrase and derivatives without a methyl group on the oxazine ring were more potent against topoisomerase II than those with a methyl group. Among these derivatives, DR-3355, the S isomer of ofloxacin, showed the highest activity against DNA gyrase and low activity against topoisomerase II. These results indicate that the methyl group on the oxazine ring plays an important role in the inhibitory activities of ofloxacin derivatives for these enzymes. PMID:1850968

  9. Electron scattering by molecules. II - Experimental methods and data

    NASA Technical Reports Server (NTRS)

    Trajmar, S.; Chutjian, A.; Register, D. F.

    1983-01-01

    Experimental techniques for measuring electron-molecule collision cross sections are briefly summarized. A survey of the available experimental cross section data is presented. The emphasis here is on elastic scattering, rotational, vibrational and electronic excitations, total electron scattering, and momentum transfer in the few eV to few hundred eV impact energy range. Reference is made to works concerned with high energy electron scattering, innershell and multi-electron excitations, conicidence methods and electron scattering in laser fields.

  10. Electron scattering by molecules. II - Experimental methods and data

    NASA Technical Reports Server (NTRS)

    Trajmar, S.; Chutjian, A.; Register, D. F.

    1983-01-01

    Experimental techniques for measuring electron-molecule collision cross sections are briefly summarized. A survey of the available experimental cross section data is presented. The emphasis here is on elastic scattering, rotational, vibrational and electronic excitations, total electron scattering, and momentum transfer in the few eV to few hundred eV impact energy range. Reference is made to works concerned with high energy electron scattering, innershell and multi-electron excitations, conicidence methods and electron scattering in laser fields.

  11. LuxGLM: a probabilistic covariate model for quantification of DNA methylation modifications with complex experimental designs.

    PubMed

    Äijö, Tarmo; Yue, Xiaojing; Rao, Anjana; Lähdesmäki, Harri

    2016-09-01

    5-methylcytosine (5mC) is a widely studied epigenetic modification of DNA. The ten-eleven translocation (TET) dioxygenases oxidize 5mC into oxidized methylcytosines (oxi-mCs): 5-hydroxymethylcytosine (5hmC), 5-formylcytosine (5fC) and 5-carboxylcytosine (5caC). DNA methylation modifications have multiple functions. For example, 5mC is shown to be associated with diseases and oxi-mC species are reported to have a role in active DNA demethylation through 5mC oxidation and DNA repair, among others, but the detailed mechanisms are poorly understood. Bisulphite sequencing and its various derivatives can be used to gain information about all methylation modifications at single nucleotide resolution. Analysis of bisulphite based sequencing data is complicated due to the convoluted read-outs and experiment-specific variation in biochemistry. Moreover, statistical analysis is often complicated by various confounding effects. How to analyse 5mC and oxi-mC data sets with arbitrary and complex experimental designs is an open and important problem. We propose the first method to quantify oxi-mC species with arbitrary covariate structures from bisulphite based sequencing data. Our probabilistic modeling framework combines a previously proposed hierarchical generative model for oxi-mC-seq data and a general linear model component to account for confounding effects. We show that our method provides accurate methylation level estimates and accurate detection of differential methylation when compared with existing methods. Analysis of novel and published data gave insights into to the demethylation of the forkhead box P3 (Foxp3) locus during the induced T regulatory cell differentiation. We also demonstrate how our covariate model accurately predicts methylation levels of the Foxp3 locus. Collectively, LuxGLM method improves the analysis of DNA methylation modifications, particularly for oxi-mC species. An implementation of the proposed method is available under MIT license at https

  12. Tetra-μ-benzoato-bis­[(6-methyl­quino­line)­copper(II)

    PubMed Central

    Yu, Seung Man; Park, Chi-Ho; Kim, Pan-Gi; Kim, Cheal; Kim, Youngmee

    2008-01-01

    In the title compound, [Cu2(C7H5O2)4(C10H9N)2], the paddle-wheel-type dinuclear complex is constructed by four bridging benzoate groups and two terminal 6-methyl­quinoline ligands. The asymmetric unit contains one-half of the whole mol­ecule, and there is an inversion center at the mid-point of the Cu⋯Cu bond. The octa­hedral coordination of each Cu atom, with four O atoms in the equatorial plane, is completed by the N atom of the 6-methyl­quinoline mol­ecule [Cu—N = 2.212 (2) Å] and by another Cu atom [Cu⋯Cu = 2.6939 (13) Å]. The Cu atom lies 0.234 Å out of the plane of the four O atoms. The molecular packing is stabilized by one intramolecular C—H⋯O as well as C—H⋯π and π–π interactions. PMID:21202752

  13. Tetra-μ-benzoato-bis-[(6-methyl-quino-line)-copper(II)].

    PubMed

    Yu, Seung Man; Park, Chi-Ho; Kim, Pan-Gi; Kim, Cheal; Kim, Youngmee

    2008-06-07

    In the title compound, [Cu(2)(C(7)H(5)O(2))(4)(C(10)H(9)N)(2)], the paddle-wheel-type dinuclear complex is constructed by four bridging benzoate groups and two terminal 6-methyl-quinoline ligands. The asymmetric unit contains one-half of the whole mol-ecule, and there is an inversion center at the mid-point of the Cu⋯Cu bond. The octa-hedral coordination of each Cu atom, with four O atoms in the equatorial plane, is completed by the N atom of the 6-methyl-quinoline mol-ecule [Cu-N = 2.212 (2) Å] and by another Cu atom [Cu⋯Cu = 2.6939 (13) Å]. The Cu atom lies 0.234 Å out of the plane of the four O atoms. The molecular packing is stabilized by one intramolecular C-H⋯O as well as C-H⋯π and π-π interactions.

  14. Experimental Realization of Type-II Dirac Fermions in a PdTe2 Superconductor

    NASA Astrophysics Data System (ADS)

    Noh, Han-Jin; Jeong, Jinwon; Cho, En-Jin; Kim, Kyoo; Min, B. I.; Park, Byeong-Gyu

    2017-07-01

    A Dirac fermion in a topological Dirac semimetal is a quadruple-degenerate quasiparticle state with a relativistic linear dispersion. Breaking either time-reversal or inversion symmetry turns this system into a Weyl semimetal that hosts double-degenerate Weyl fermion states with opposite chiralities. These two kinds of quasiparticles, although described by a relativistic Dirac equation, do not necessarily obey Lorentz invariance, allowing the existence of so-called type-II fermions. The recent theoretical discovery of type-II Weyl fermions evokes the prediction of type-II Dirac fermions in PtSe2 -type transition metal dichalcogenides, expecting experimental confirmation. Here, we report an experimental realization of type-II Dirac fermions in PdTe2 by angle-resolved photoemission spectroscopy combined with ab initio band calculations. Our experimental finding shows the first example that has both superconductivity and type-II Dirac fermions, which turns the topological material research into a new phase.

  15. Bis[2-amino-6-methyl-pyrimidin-4(1H)-one-κN,O]dichloridocadmium(II).

    PubMed

    Kaabi, Kamel; El Glaoui, Meher; Pereira Silva, P S; Ramos Silva, M; Ben Nasr, Cherif

    2010-09-08

    In the title compound, [CdCl(2)(C(5)H(7)N(3)O)(2)], the Cd(II) atom is six-coordinated by two heterocyclic N atoms [Cd-N = 2.261 (2) and 2.286 (2) Å] and two O atoms [Cd-O = 2.624 (2) and 2.692 (2) Å] from two bidentate chelate 2-amino-6-methyl-pyrimidin-4(1H)-one ligands and two chloride ions [Cd-Cl = 2.4674 (6) and 2.4893 (7) Å]. The crystal packing is characterized by an open-framework architecture with the crystal packing stabilized by inter-molecular N-H⋯Cl and N-H⋯O hydrogen bonds.

  16. Diaqua-(5-methyl-1H-pyrazole-3-carboxyl-ato)(4-nitro-benzoato)copper(II).

    PubMed

    Hu, Fei-Long; Yin, Xian-Hong; Feng, Yu; Mi, Yan; Zhang, Shan-Shan

    2009-01-23

    In the title complex, [Cu(C(7)H(4)NO(4))(C(5)H(5)N(2)O(2))(H(2)O)(2)], the Cu(II) ion is coordinated in a slightly distorted square-pyramidal enviroment. The basal plane is formed by an N atom and an O atom from a 5-methyl-1H-pyrazole-3-carboxyl-ate ligand and by two O atoms from two water ligands. The apical position is occupied by a carboxylate O atom from a 4-nitro-benzoate ligand. In the crystal structure, inter-molecular O-H⋯O and N-H⋯O hydrogen bonds link complex moleclues, forming extended chains parallel to the a axis.

  17. Tumors with unmethylated MLH1 and the CpG island methylator phenotype are associated with a poor prognosis in stage II colorectal cancer patients

    PubMed Central

    Fu, Tao; Liu, Yanliang; Li, Kai; Wan, Weiwei; Pappou, Emmanouil P.; Iacobuzio-Donahue, Christine A.; Kerner, Zachary; Baylin, Stephen B.; Wolfgang, Christopher L.; Ahuja, Nita

    2016-01-01

    We previously developed a novel tumor subtype classification model for duodenal adenocarcinomas based on a combination of the CpG island methylator phenotype (CIMP) and MLH1 methylation status. Here, we tested the prognostic value of this model in stage II colorectal cancer (CRC) patients. Tumors were assigned to CIMP+/MLH1-unmethylated (MLH1-U), CIMP+/MLH1-methylated (MLH1-M), CIMP−/MLH1-U, or CIMP−/MLH1-M groups. Age, tumor location, lymphovascular invasion, and mucin production differed among the four patient subgroups, and CIMP+/MLH1-U tumors were more likely to have lymphovascular invasion and mucin production. Kaplan-Meier analyses revealed differences in both disease-free survival (DFS) and overall survival (OS) among the four groups. In a multivariate analysis, CIMP/MLH1 methylation status was predictive of both DFS and OS, and DFS and OS were shortest in CIMP+/MLH1-U stage II CRC patients. These results suggest that tumor subtype classification based on the combination of CIMP and MLH1 methylation status is informative in stage II CRC patients, and that CIMP+/MLH1-U tumors exhibit aggressive features and are associated with poor clinical outcomes. PMID:27880934

  18. Phase I/II study of azacitidine and capecitabine/oxaliplatin (CAPOX) in refractory CIMP-high metastatic colorectal cancer: evaluation of circulating methylated vimentin.

    PubMed

    Overman, Michael J; Morris, Van; Moinova, Helen; Manyam, Ganiraju; Ensor, Joe; Lee, Michael S; Eng, Cathy; Kee, Bryan; Fogelman, David; Shroff, Rachna T; LaFramboise, Thomas; Mazard, Thibault; Feng, Tian; Hamilton, Stanley; Broom, Bradley; Lutterbaugh, James; Issa, Jean-Pierre; Markowitz, Sanford D; Kopetz, Scott

    2016-10-11

    Hypermethylation of promoter CpG islands (CIMP) has been strongly implicated in chemotherapy resistance and is implicated in the pathogenesis of a subset of colorectal cancers (CRCs) termed CIMP-high. This phase I/II study in CRC (phase II portion restricted to CIMP-high CRC), treated fluoropyrimidine/oxaliplatin refractory patients with azacitidine (75 mg/m2/day subcutaneously D1-5) and CAPOX (capecitibine and oxaliplatin) every three weeks. Twenty-six patients (pts) were enrolled in this study: 15 pts (12 treated at MTD) in phase I and 11 pts in phase II. No dose limiting toxicities were observed. A total of 14 pts were CIMP-high. No responses were seen. CIMP-high status did not correlate with efficacy endpoints [stable disease (SD) or progression-free survival (PFS)] or baseline vimentin methylation level. Changes in vimentin methylation over time did not correlate with efficacy outcomes. Baseline methylated vimentin correlated with tumor volume (P<0.001) and higher levels of baseline methylation correlated with the obtainment of stable disease (P=0.04). Azacitidine and CAPOX were well tolerated with high rates of stable disease in CIMP-high pts, but no objective responses. Serum methylated vimentin may be associated with benefit from a regimen including a hypomethylation agent, although this study is not able to separate a potential prognostic or predictive role for the biomarker.

  19. H2O2-reactivity of copper(II) complexes supported by tris[(pyridin-2-yl)methyl]amine ligands with 6-phenyl substituents.

    PubMed

    Kunishita, Atsushi; Kubo, Minoru; Ishimaru, Hirohito; Ogura, Takashi; Sugimoto, Hideki; Itoh, Shinobu

    2008-12-15

    The structure and H(2)O(2)-reactivity of a series of copper(II) complexes supported by tris[(pyridin-2-yl)methyl]amine (TPA) derivatives having a phenyl group at the 6-position of pyridine donor group(s) [(6-phenylpyridin-2-yl)methyl]bis[(pyridin-2-yl)methyl]amine (Ph(1)TPA), bis[(6-phenylpyridin-2-yl)methyl][(pyridin-2-yl)methyl]amine (Ph(2)TPA), and tris[(6-phenylpyridin-2-yl)methyl]amine (Ph(3)TPA) have systematically been examined to get insights into the aromatic substituent (6-Ph) effects on the coordination chemistry of TPA ligand system. The X-ray crystallographic analyses have revealed that [Cu(II)(TPA)(CH(3)CN)](ClO(4))(2) (CuTPA) and [Cu(II)(Ph(3)TPA)(CH(3)CN)](ClO(4))(2) (3) exhibit a trigonal bipyramidal structure, whereas [Cu(II)(Ph(1)TPA)(CH(3)CN)](ClO(4))(2) (1) shows a slightly distorted square pyramidal structure and [Cu(II)(Ph(2)TPA)(CH(3)CN)](ClO(4))(2) (2) has an intermediate structure between trigonal bipyramidal and square pyramidal. On the other hand, the UV-vis and ESR data have suggested that all the copper(II) complexes have a similar trigonal bipyramidal structure in solution. The redox potentials of CuTPA, 1, 2, and 3 have been determined as E(1/2) = -0.34, -0.28, -0.16, and -0.04 mV vs Ag/AgNO(3), respectively, demonstrating that introduction of each 6-Ph group causes positive shift of E(1/2) about 0.1 V. Notable difference in H(2)O(2)-reactivity has been found among the copper(II) complexes. Namely, CuTPA and 1 afforded mononuclear copper(II)-hydroperoxo complexes CuTPA-OOH and 1-OOH, respectively, whereas complex 2 provided bis(mu-oxo)dicopper(III) complex 2-oxo. On the other hand, copper(II) complex 3 was reduced to the corresponding copper(I) complex 3(red). On the basis of the H(2)O(2)-reactivity together with the X-ray structures and the redox potentials of the copper(II) complexes, the substituent effects of 6-Ph are discussed in detail.

  20. 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.

  1. Experimental trampling of vegetation. II. Predictors of resistance and resilience

    Treesearch

    David N. Cole

    1995-01-01

    1. Experimental trampling was conducted in 18 vegetation types in five separate mountain regions in the United States. Each type was trampled 0-500 times and vegetation response was assessed 2 weeks and 1 year after trampling. 2. The response of vegetation to trampling is expressed in terms of three indices: resistance, tolerance and resilience. Resistance...

  2. Methyl cellulose gel obstructed bone formation by GBR: an experimental study in rats.

    PubMed

    Lioubavina-Hack, Natalia; Karring, Thorkild; Lynch, Samuel E; Lindhe, Jan

    2005-12-01

    To evaluate whether bone formation under Teflon capsules may be enhanced by concomitant implantation of recombinant human platelet-derived growth factor-BB/insulin-like growth factor-I (rhPDGF-BB/IGF-I) incorporated into a methyl cellulose gel. Fifty-five male 6-month-old albino rats of the Wistar strain were used in the study. The lateral aspect of the mandibular ramus was exposed on both sides of the jaw. In 70 sites, the periosteum was removed from the ramus, leaving the bone denuded, while in 35 sites, it was preserved. On 10 non-periosteal (P-) sites and five periosteal (P+) sites, an empty rigid teflon capsule (d=7 mm), serving as control, was placed on the ramus. In the 40 test animals, the capsule placed on the one side of the jaw was filled at random with one of three different concentrations (1,200, 600, 150 microg/ml) of rhPDGF-BB/IGF-I gel. The capsules placed on the contralateral side of the jaw contained a placebo methyl cellulose gel. Each growth factor group, defined according to the gel concentration, and the placebo group contained 10 capsules placed on the P- side and five capsules placed on the P+ side. Two months after surgery, all animals were sacrificed. Histologic analysis revealed that in the non-filled control capsules, the amount of new bone including the bone marrow was 29.9% and 39.7% of the capsule area on the P- and P+ sides, respectively. In the test capsules with the growth factor gel and placed on the P-sides, the amounts of new bone ranged from 5.6% to 6.3%, which were similar (p>0.05) to that formed in the capsules filled with the methyl cellulose gel (5.5%). New bone formation was larger in the capsules on the P+ sides than in those on the P- sides but was similar in the capsules with different growth factor concentrations (range 17.9-19.6%) and in those with placebo gel (21.0%). In all groups, the carrier gel was poorly absorbed and occupied most of the capsules. Local application of a methyl cellulose gel obstructed bone

  3. Synthesis, characterization, computational studies, antimicrobial activities and carbonic anhydrase inhibitor effects of 2-hydroxy acetophenone-N-methyl p-toluenesulfonylhydrazone and its Co(II), Pd(II), Pt(II) complexes

    NASA Astrophysics Data System (ADS)

    Özbek, Neslihan; Alyar, Saliha; Memmi, Burcu Koçak; Gündüzalp, Ayla Balaban; Bahçeci, Zafer; Alyar, Hamit

    2017-01-01

    2-Hydroxyacetophenone-N-methyl p-toluenesulfonylhydrazone (afptsmh) derived from p-toluenesulfonicacid-1-methylhydrazide (ptsmh) and its Co(II), Pd(II), Pt(II) complexes were synthesized for the first time. Synthesized compounds were characterized by spectroscopic methods (FT-IR, 1Hsbnd 13C NMR, LC-MS, UV-vis), magnetic susceptibility and conductivity measurements. 1H and 13C shielding tensors for crystal structure of ligand were calculated with GIAO/DFT/B3LYP/6-311++G(d,p) methods in CDCl3. The vibrational band assignments were performed at B3LYP/6-311++G(d,p) theory level combined with scaled quantum mechanics force field (SQMFF) methodology. The antibacterial activities of synthesized compounds were studied against some Gram positive and Gram negative bacteria by using microdilution and disc diffusion methods. In vitro enzyme inhibitory effects of the compounds were measured by UV-vis spectrophotometer. The enzyme activities against human carbonic anhydrase II (hCA II) were evaluated as IC50 (the half maximal inhibitory concentration) values. It was found that afptsmh and its metal complexes have inhibitory effects on hCA II isoenzyme. General esterase activities were determined using alpha and beta naphtyl acetate substrates (α- and β-NAs) of Drosophila melanogaster (D. melanogaster). Activity results show that afptsmh does not strongly affect the bacteria strains and also shows poor inhibitory activity against hCAII isoenzyme whereas all complexes posses higher biological activities.

  4. Bromidotetra-kis-(1H-2-ethyl-5-methyl-imidazole-κN)copper(II) bromide.

    PubMed

    Godlewska, Sylwia; Baranowska, Katarzyna; Socha, Joanna; Dołęga, Anna

    2011-12-01

    The Cu(II) ion in the title compound, [CuBr(C(6)H(10)N(2))(4)]Br, is coordinated in a square-based-pyramidal geometry by the N atoms of four imidazole ligands and a bromide anion in the apical site. Both the Cu(II) and Br(-) atoms lie on a crystallographic fourfold axis. In the crystal, the [CuBr(C(6)H(10)N(2))(4)](+) complex cations are linked to the uncoordinated Br(-) anions (site symmetry [Formula: see text]) by N-H⋯Br hydrogen bonds, generating a three-dimensional network. The ethyl group of the imidazole ligand was modelled as disordered over two orientations with occupancies of 0.620 (8) and 0.380 (8).

  5. Eimeria tenella: experimental studies on the development of resistance to amprolium, clopidol and methyl benzoquate.

    PubMed

    Chapman, H D

    1978-04-01

    The development of resistance by the Houghton strain of Eimeria tenella to the anticoccidial drugs amprolium, clopidol and methyl benzoquate has been studied. Resistance to amprolium and clopidol developed more readily in experiments where a large number of coccidia were exposed to the drug, either by increasing the number of oocysts in the inoculum or by increasing the number of birds in the group. When 45 birds were given 2.0 X 10(6) oocysts, resistance to amprolium and clopidol appeared after 6 and 7 passages respectively. In previous experiments, under similar conditions, resistance to robenidine developed after 6 passages, suggesting little difference between these three drugs. Resistance to amprolium and clopidol arose gradually as the concentration of drug was increased, but resistance to methyl benzoquate appeared in a single step from sensitivity to high-level resistance. Both amprolium and clopidol-resistant lines showed an 8-fold reduction in drug sensitivity. Attempts to measure the degree of resistance by calculation of the ED50 were unsuccessful.

  6. Two nickel(II) bis[(pyridin-2-yl)methyl]amine complexes with homophthalic and benzene-1,2,4,5-tetracarboxylic acids.

    PubMed

    Atria, Ana María; Garland, Maria Teresa; Baggio, Ricardo

    2014-06-01

    Two new Ni(II) complexes involving the ancillary ligand bis[(pyridin-2-yl)methyl]amine (bpma) and two different carboxylate ligands, i.e. homophthalate [hph; systematic name: 2-(2-carboxylatophenyl)acetate] and benzene-1,2,4,5-tetracarboxylate (btc), namely catena-poly[[aqua{bis[(pyridin-2-yl)methyl]amine-κ(3)N,N',N''}nickel(II)]-μ-2-(2-carboxylatophenyl)aceteto-κ(2)O:O'], [Ni(C9H6O4)(C12H13N3)(H2O)]n, and (μ-benzene-1,2,4,5-tetracarboxylato-κ(4)O(1),O(2):O(4),O(5))bis(aqua{bis[(pyridin-2-yl)methyl]amine-κ(3)N,N',N''}nickel(II)) bis(triaqua{bis[(pyridin-2-yl)methyl]amine-κ(3)N,N',N''}nickel(II)) benzene-1,2,4,5-tetracarboxylate hexahydrate, [Ni2(C10H2O8)(C12H13N3)2(H2O)2]·[Ni(C12H13N3)(H2O)3]2(C10H2O8)·6H2O, (II), are presented. Compound (I) is a one-dimensional polymer with hph acting as a bridging ligand and with the chains linked by weak C-H···O interactions. The structure of compound (II) is much more complex, with two independent Ni(II) centres having different environments, one of them as part of centrosymmetric [Ni(bpma)(H2O)]2(btc) dinuclear complexes and the other in mononuclear [Ni(bpma)(H2O)3](2+) cations which (in a 2:1 ratio) provide charge balance for btc(4-) anions. A profuse hydrogen-bonding scheme, where both coordinated and crystal water molecules play a crucial role, provides the supramolecular linkage of the different groups.

  7. Experimental analysis of the mechanism of chromatin remodeling by RNA polymerase II

    PubMed Central

    Gaykalova, Daria A.; Kulaeva, Olga I.; Pestov, Nikolai A.; Hsieh, Fu-Kai; Studitsky, Vasily M.

    2014-01-01

    The vital process of transcription by RNA polymerase II (Pol II) occurs in chromatin environment in eukaryotic cells; in fact, moderately transcribed genes retain nucleosomal structure. Recent studies suggest that chromatin structure presents a strong barrier for transcribing Pol II in vitro, and that DNA-histone interactions are only partially and transiently disrupted during transcript elongation on moderately active genes. Furthermore, elongating Pol II complex is one of the major targets during gene regulation. Below we describe a highly purified, defined experimental system that recapitulates many important properties of transcribed chromatin in vitro and allows detailed analysis of the underlying mechanisms. PMID:22910212

  8. 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)X 2] 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

  9. 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.

  10. 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.

  11. Angiotensin II Moderately Decreases Plasmodium Infection and Experimental Cerebral Malaria in Mice.

    PubMed

    Gallego-Delgado, Julio; Baravian, Charlotte; Edagha, Innocent; Ty, Maureen C; Ruiz-Ortega, Marta; Xu, Wenyue; Rodriguez, Ana

    2015-01-01

    Angiotensin II, a peptide hormone that regulates blood pressure, has been proposed as a protective factor against cerebral malaria based on a genetic analysis. In vitro studies have documented an inhibitory effect of angiotensin II on Plasmodium growth, while studies using chemical inhibitors of angiotensin II in mice showed protection against experimental cerebral malaria but not major effects on parasite growth. To determine whether the level of angiotensin II affects Plasmodium growth and/or disease outcome in malaria, elevated levels of angiotensin II were induced in mice by intradermal implantation of osmotic mini-pumps providing constant release of this hormone. Mice were then infected with P. berghei and monitored for parasitemia and incidence of cerebral malaria. Mice infused with angiotensin II showed decreased parasitemia seven days after infection. The development of experimental cerebral malaria was delayed and a moderate increase in survival was observed in mice with elevated angiotensin II, as confirmed by decreased number of cerebral hemorrhages compared to controls. The results presented here show for the first time the effect of elevated levels of angiotensin II in an in vivo model of malaria. The decreased pathogenesis observed in mice complements a previous human genetic study, reinforcing the hypothesis of a beneficial effect of angiotensin II in malaria.

  12. Angiotensin II Moderately Decreases Plasmodium Infection and Experimental Cerebral Malaria in Mice

    PubMed Central

    Gallego-Delgado, Julio; Baravian, Charlotte; Edagha, Innocent; Ty, Maureen C.; Ruiz-Ortega, Marta; Xu, Wenyue; Rodriguez, Ana

    2015-01-01

    Angiotensin II, a peptide hormone that regulates blood pressure, has been proposed as a protective factor against cerebral malaria based on a genetic analysis. In vitro studies have documented an inhibitory effect of angiotensin II on Plasmodium growth, while studies using chemical inhibitors of angiotensin II in mice showed protection against experimental cerebral malaria but not major effects on parasite growth. To determine whether the level of angiotensin II affects Plasmodium growth and/or disease outcome in malaria, elevated levels of angiotensin II were induced in mice by intradermal implantation of osmotic mini-pumps providing constant release of this hormone. Mice were then infected with P. berghei and monitored for parasitemia and incidence of cerebral malaria. Mice infused with angiotensin II showed decreased parasitemia seven days after infection. The development of experimental cerebral malaria was delayed and a moderate increase in survival was observed in mice with elevated angiotensin II, as confirmed by decreased number of cerebral hemorrhages compared to controls. The results presented here show for the first time the effect of elevated levels of angiotensin II in an in vivo model of malaria. The decreased pathogenesis observed in mice complements a previous human genetic study, reinforcing the hypothesis of a beneficial effect of angiotensin II in malaria. PMID:26376293

  13. Hexa-μ(2)-chlorido-μ(4)-oxido-tetra-kis-[(3-methyl-5-phenyl-1H-pyrazole-κN)copper(II)].

    PubMed

    He, Hongshan

    2011-01-08

    The title compound, [Cu(4)Cl(6)O(C(10)H(10)N(2))(4)], contains four Cu(II) atoms which are bridged by six chloride anions. The central O atom is located on a crystallographic fourfold roto-inversion axis. Each Cu(II) atom is coordinated by an N atom of a neutral monodentate 3-methyl-5-phenyl-pyrazole ligand, three Cl(-) anions, and one O(2-) anion. The geometry at each Cu(II) atom is distorted trigonal-bipyramidal, with the three Cl(-) ions in the equatorial plane and the N and O atoms in the axial positions.

  14. Inhibition of human catechol-O-methyltransferase-mediated dopamine O-methylation by daphnetin and its Phase II metabolites.

    PubMed

    Liang, Si-Cheng; Ge, Guang-Bo; Xia, Yang-Liu; Pei-Pei, Dong; Ping, Wang; Qi, Xiao-Yi; Cai-Xia, Tu; Ling, Yang

    2016-07-20

    1. Finding and developing inhibitors of catechol-O-methyltransferase (COMT) from natural products is highly recommended. Daphnetin, a naturally occurring catechol from the family thymelaeaceae, has a chemical structure similar to several potent COMT inhibitors reported previously. Here the potential of daphnetin and its Phase II metabolites as inhibitors of COMT was investigated with human liver cytosol (HLC). 2. Daphnetin and its methylated metabolite (8-O-methyldaphnetin) were found to inhibit COMT-mediated dopamine O-methylation in a dose-dependent manner. The IC50 values for daphnetin (0.51∼0.53 μM) and 8-O-methyldaphnetin (22.5∼24.3 μM) were little affected by changes in HLC concentrations. Further kinetic analysis showed the differences in inhibition type and parameters (Ki) between daphnetin (competitive, 0.37 μM) and 8-O-methyldaphnetin (noncompetitive, 25.7 μM). Other metabolites, including glucuronidated and sulfated species, showed negligible inhibition against COMT. By using in vitro-in vivo extrapolation (IV-IVE), a 24.3-fold increase in the exposure of the COMT substrates was predicted when they are co-administrated with daphnetin. 3. With high COMT-inhibiting activity, daphnetin could serve as a lead compound for the design and development of new COMT inhibitors. Also, much attention should be paid to the clinical impact of combination of daphnetin and herbal preparations containing daphnetin with the drugs primarily cleared by COMT.

  15. Bis[bis-(penta-methyl-cyclo-penta-dien-yl)cobalt(III)] tetra-chlorido-cobaltate(II) di-chloro-methane disolvate.

    PubMed

    Merola, Joseph S; Ngo, Mai; Karpin, George W

    2013-01-01

    The title compound, [Co(C10H15)2]2[CoCl4]·2CH2Cl2, was isolated as a dichloromethane solvate and was formed in the reaction between lithium penta-methyl-cyclo-penta-dienide and anyhydrous cobalt(II) chloride in tetra-hydro-furan. There are two deca-methyl-cobaltocenium cations, one tetrachloridocobaltate(II) anion and two di-chloro-methane solvent mol-ecules in the formula unit. There is a slight disorder of the di-chloro-methane solvent which was treated with a two-site model [occupancy rates = 0.765 (4) and 0.235 (4)]. The di-chloro-methane mol-ecules display significant C-H⋯Cl inter-actions with the tetrachloridocobaltate(II) dianion. The cobalt atom of the deca-methyl-cobaltocenium cation sits on a twofold rotation axis, with only one penta-methyl-cyclo-penta-diene ligand being unique and the second generated by symmetry. The cobalt atom of the [CoCl4](-2) ion sits on a special site with -4 symmetry, with one unique chloride ligand and the others generated by the fourfold inversion axis.

  16. Sequential quantification of methyl mercury in biological materials by selective reduction in the presence of mercury(II), using two gas liquid separators

    NASA Astrophysics Data System (ADS)

    Monteiro, Alcicléa da Conceição Pereira; de Andrade, Ly Santabaia N.; Luna, Aderval S.; de Campos, Reinaldo Calixto

    2002-12-01

    The present procedure is based on the sequential selective reduction of mercury(II) and methyl mercury using two gas-liquid separators in series. Cold vapor atomic absorption spectrometry was used for detection. Mercury(II) is reduced by a 0.01% m/v sodium tetrahydroborate solution and driven to the absorption cell in the first separator. The methyl mercury species is reduced by the same reductant but at a 0.3% m/v concentration, and in the presence of iron(III) chloride. Parameters such as argon flow rate, and the NaBH 4 and dithiophosphoric acid diacyl ester concentrations were optimized. At the optimized conditions, and using aqueous standards for calibration, the corresponding limits of detection (3σ b, n=10) were 400 and 600 ng l -1 for mercury(II) and methyl mercury, respectively. The sample throughput was 12 h -1. The procedure was used for the determination of methyl mercury in dogfish liver and dogfish muscle certified reference materials, and good concordance between found and certified values was observed.

  17. 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

    Asegbeloyin, Jonnie N; Ujam, Oguejiofo T; Okafor, Emmanuel C; Babahan, Ilknur; Coban, Esin Poyrazoglu; Ozmen, 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 (HL(1)), 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 HL(1) 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.

  18. Growth of lithium triborate crystals. II. Experimental results

    NASA Astrophysics Data System (ADS)

    Parfeniuk, C.; Samarasekera, I. V.; Weinberg, F.; Edel, J.; Fjeldsted, K.; Lent, B.

    1996-02-01

    In Part I [C. Parfeniuk, I.V. Samarasekera and F. Weinberg, J. Crystal Growth 158 (1996) 514], a mathematical model of the flux growth of lithium triborate (LBO) crystals was used to calculate the temperature distribution and fluid flow in the melt during growth. In this report the model results are related to experimental observations. Temperature measurements in the melt, for different crucible rotation rates, are compared to the corresponding temperatures determined from the model. Direct observations of fluid flow in the melt, using a transparent glycerol/water solution as a physical model, are related to the calculated flow paths and velocities. As the LBO crystal grows, the rejected MoO 3 flux concentrates ahead of the interface leading to the formation of eutectic phases. The factors leading to the formation of these phases are examined, using flow velocity values determined from the model. A number of LBO crystals were grown, first using convenient growth parameters, and then using parameters determined from the model results. The size and quality of the crystals obtained are discussed and related to the growth conditions.

  19. Di-methyl-ammonium tetra-aqua-(hydrogen-sulfato)-sulfato-cuprate(II).

    PubMed

    Held, Peter

    2014-04-01

    In the title salt, [(CH3)2NH2][Cu(HSO4)(SO4)(H2O)4], one type of cation and anion is present in the asymmetric unit. The Cu(II) atom in the complex anion, [Cu(HSO4)(SO4)(H2O)4](-), has a tetra-gonal bipyramidal [4 + 2] coordination caused by a Jahn-Teller distortion, with the aqua ligands in equatorial and two O atoms of tetra-hedral HSO4 and SO4 units in apical positions. Both types of ions form sheets parallel to (010). The inter-connection within and between the sheets is reinforced by O-H⋯O and N-H⋯O hydrogen bonds, respectively, involving the water mol-ecules, the two types of sulfate anions and the ammonium groups.

  20. Experimental studies of U-Pu-Zr fast reactor fuel pins in EBR-II (Experimental Breeder Reactor)

    SciTech Connect

    Pahl, R.G.; Porter, D.L.; Lahm, C.E.; Hofman, G.L.

    1988-01-01

    The Integral Fast Reactor (IFR) is a generic reactor concept under development by Argonne National Laboratory. Much of the technology for the IFR is being demonstrated at the Experimental Breeder Reactor II (EBR-II) on the Department of Energy site near Idaho Falls, Idaho. The IFR concept relies on four technical features to achieve breakthroughs in nuclear power economics and safety: (1) a pool-type reactor configuration, (2) liquid sodium cooling, (3) metallic fuel, and (4) an integral fuel cycle with on-site reprocessing. The purpose of this paper will be to summarize our latest results of irradiation testing uranium-plutonium-zirconium (U-Pu-Zr) fuel in the EBR-II. 10 refs., 13 figs., 2 tabs.

  1. Experimental Breeder Reactor II (EBR-II): Instrumentation for core surveillance

    SciTech Connect

    Christensen, L.J.

    1989-01-01

    EBR-II has operated for 25 years in support of several major programs. During this time period, several of the original, non-replaceable, flow sensors, RDT sensors and thermocouples have failed in the primary system. This has led to the development of new sensors and the use of calculated values using computer models of the plant. It is important for the next generation of LMR reactors to minimize or eliminate the use of non-replaceable sensors. EBR-II is perhaps the best modeled reactor in the world, thanks to a dedicated T-H analysis program. The success of this program relied on excellent measurements of temperature and flow in subassemblies in the core. The instrumented subassemblies of the XX series provided that measurement capability. From this test series, EBR-II calculations showed that the core could withstand a loss-of-flow without scram accident and a loss-of-heat sink without scram accident from full reactor power without core damage. From this, reactor designers can now design with confidence, inherently safe reactors. 11 refs., 8 figs.

  2. Structure and isomerization comparison of Zn(II), Cd(II) and Hg(II) perchlorate complexes of 2,6-bis([(2-pyridyl-methyl)amino]methyl)pyridine.

    PubMed

    Carra, Bradley J; Berry, Steven M; Pike, Robert D; Bebout, Deborah C

    2013-10-28

    The divalent zinc triad perchlorate coordination chemistry of 2,6-bis([(2-pyridyl-methyl)amino]methyl)pyridine (L) was investigated by X-ray crystallography and solution state (1)H NMR. New complexes [HgL(ClO4)2] (1) and [CdL(ClO4)2] (2) were isolated as bicapped distorted square pyramidal racemates, contrasting with the approximate trigonal bipyramidal structure of [ZnL](ClO4)2 (3). Although rapid inter- and intramolecular exchange is common for simple complexes of zinc triad metal ions, conditions for slow intramolecular isomerization on both the δ and J(HH) time scales were established for 1, 2 and 3. Trends in geminal (1)H coupling suggested that an asymmetric structure was favored for all three metal ions at or below 40 °C. Contributions of a symmetric structure to solution equilibria were both temperature- and metal ion-dependent. Spectral trends were consistent with interconversion of a pair of enantiomeric square pyramidal ligand conformers through a symmetric trigonal bipyramidal ligand conformer by M-N bond cleavage and nitrogen inversion. Racemization was slower than the coupling constant time scale up to 40 °C for all complexes. Differential stabilization of specific small ligand conformations in solution has potential toxicological significance.

  3. Experimental and theoretical study of methyl-p-aminobenzoate/ammonia complexes. I. MAB(NH3)1

    NASA Astrophysics Data System (ADS)

    Fernández, J. A.; Longarte, A.; Unamuno, I.; Castaño, F.

    2000-11-01

    Methyl-p-aminobenzoate(NH3)1 complex, henceforth MAB(NH3)1, prepared in a pulsed supersonic expansion, has been examined by laser mass-selective spectroscopies and density functional theory calculations, aiming to ascertain its isomer number, structures, identification, ionization energies, and vibrational assignments. Resonance enhanced multiphoton ionization and hole burning spectra of the species in supersonic beams show two 000 transitions redshifted by -715 and -709 cm-1 from that of bare MAB band origin and are plausibly associated with two different isomers, whereas ab initio calculations indicate the likely existence of five stable isomer structures. Identification of the experimental isomer spectra with the calculated structures is reported and, in particular, several isomer vibrational bands are identified by contrast with the calculated modes. Properties and features of the MAB(NH3)1 are compared with those of the MAB/water complexes.

  4. Cardiac angiotensin II type I and type II receptors are increased in rats submitted to experimental hypothyroidism

    PubMed Central

    Carneiro-Ramos, M S; Diniz, G P; Almeida, J; Vieira, R L P; Pinheiro, S V B; Santos, R A; Barreto-Chaves, M L M

    2007-01-01

    This study assessed the behaviour of angiotensin II (Ang II) receptors in an experimental hypothyroidism model in male Wistar rats. Animals were subjected to thyroidectomy and resting for 14 days. The alteration of cardiac mass was evaluated by total heart weight (HW), right ventricle weight (RVW), left ventricle weight (LVW), ratio of HW, RVW and LVW to body weight (BW) and atrial natriuretic factor (ANF) expression. Cardiac and plasma Ang II levels and serum T3 and T4 were determined. The mRNA and protein levels of Ang II receptors were investigated by RT-PCR and Western blotting, respectively. Functional analyses were performed using binding assays. T3 and T4 levels and the haemodynamic parameters confirmed the hypothyroid state. HW/BW, RVW/BW and LVW/BW ratios and the ANF expression were lower than those of control animals. No change was observed in cardiac or plasma Ang II levels. Both AT1/AT2 mRNA and protein levels were increased in the heart of hypothyroid animals due to a significant increase of these receptors in the RV. Experiments performed in cardiomyocytes showed a direct effect promoted by low thyroid hormone levels upon AT1 and AT2 receptors, discarding possible influence of haemodynamic parameters. Functional assays showed that both receptors are able to bind Ang II. Herein, we have identified, for the first time, a close and direct relation of elevated Ang II receptor levels in hypothyroidism. Whether the increase in these receptors in hypothyroidism is an alternative mechanism to compensate the atrophic state of heart or whether it may represent a potential means to the progression of heart failure remains unknown. PMID:17540701

  5. Experimental methyl mercury encephalopathy: mechanisms of mercurial perturbation of rat brain protein synthesis

    SciTech Connect

    Cheung, M.K.

    1982-01-01

    Attempts were made to characterize the mechanism(s) of action of methyl mercury chloride (MeHg) on rat brain protein synthesis. Single i.p. injection of MeHg to young rats resulted in a dose-dependent stimulation followed by inhibition of amino acid incorporation in postmitochondrial supernatant (PMS) after 18-24 hours. Isolated ribosomes revealed a similar biphasic mercurial perturbation of amino acid incorporation when supplemented with homologous pH 5 enzymes, but these effects were reversed by substituting cytosolic pH 5 enzymes derived from control animals. In agreement with the in vivo results, a biphasic mercurial effect was observed following in vitro addition of MeHg to the PMS and to the ribosomal amino acid incorporating systems. The mercurial induced stimulation of translation appeared to be associated with an increase in the formation of 40S pre-initiation complex and 80S initiation units. The similarities in the lesions produced in vivo and in vitro suggested direct interaction of the organic heavy metal with protein synthetic targets in the brain. A model was proposed to explain the variable action of MeHg in the brain suggesting a possible existence of an endogenous inhibitor of protein synthesis that was sensitive to MeHg.

  6. An experimental study of the combined effects of n-hexane and methyl ethyl ketone.

    PubMed Central

    Takeuchi, Y; Ono, Y; Hisanaga, N; Iwata, M; Aoyama, M; Kitoh, J; Sugiura, Y

    1983-01-01

    This study was intended to determine whether or not methyl ethyl ketone (MEK) enhances the neurotoxicity of n-hexane at low concentration and after long term exposure. Separate groups of eight rats were exposed to 100 ppm n-hexane, 200 ppm MEK, 100 ppm n-hexane plus 200 ppm MEK, or fresh air in an exposure chamber for 12 hours a day for 24 weeks. The body weight, motor nerve conduction velocity (MCV), distal motor latency (DL), and mixed nerve conduction velocities (MNCVs) were measured before exposure and after four, eight, 12, 16, 20, and 24 weeks' exposure. One rat of each group was histopathologically examined after 24 weeks' exposure. Exposure of 100 ppm n-hexane did not significantly decrease the functions of the peripheral nerve throughout the experiment. Exposure to 200 ppm MEK significantly increased MCV and MNCVs and decreased DL after four weeks' exposure, but at this later stage no significant changes were found throughout the experiment by comparison with the controls. Mixed exposure to 100 ppm n-hexane plus 200 ppm MEK significantly decreased by comparison with the controls. On histopathological examination of the tail nerve, however, no changes were found in any of the exposed groups or the controls. These results suggest that MEK might enhance the neurotoxicity of n-hexane at a low concentration, and mixed exposures to n-hexane and MEK should be avoided. PMID:6830718

  7. 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.

  8. 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.

  9. 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

  10. Site-specific methylation and acetylation of lysine residues in the C-terminal domain (CTD) of RNA polymerase II

    PubMed Central

    Voss, Kirsten; Forné, Ignasi; Descostes, Nicolas; Hintermair, Corinna; Schüller, Roland; Maqbool, Muhammad Ahmad; Heidemann, Martin; Flatley, Andrew; Imhof, Axel; Gut, Marta; Gut, Ivo; Kremmer, Elisabeth; Andrau, Jean-Christophe; Eick, Dirk

    2015-01-01

    Dynamic modification of heptad-repeats with the consensus sequence Tyr1-Ser2-Pro3-Thr4-Ser5-Pro6-Ser7 of RNA polymerase II (RNAPII) C-terminal domain (CTD) regulates transcription-coupled processes. Mass spectrometry analysis revealed that K7-residues in non-consensus repeats of human RNAPII are modified by acetylation, or mono-, di-, and tri-methylation. K7ac, K7me2, and K7me3 were found exclusively associated with phosphorylated CTD peptides, while K7me1 occurred also in non-phosphorylated CTD. The monoclonal antibody 1F5 recognizes K7me1/2 residues in CTD and reacts with RNAPIIA. Treatment of cellular extracts with phosphatase or of cells with the kinase inhibitor flavopiridol unmasked the K7me1/2 epitope in RNAPII0, consistent with the association of K7me1/2 marks with phosphorylated CTD peptides. Genome-wide profiling revealed high levels of K7me1/2 marks at the transcriptional start site of genes for sense and antisense transcribing RNAPII. The new K7 modifications further expand the mammalian CTD code to allow regulation of differential gene expression. PMID:26566685

  11. An RNA polymerase II-coupled function for histone H3K36 methylation in checkpoint activation and DSB repair.

    PubMed

    Jha, Deepak Kumar; Strahl, Brian D

    2014-06-09

    Histone modifications are major determinants of DNA double-strand break (DSB) response and repair. Here we elucidate a DSB repair function for transcription-coupled Set2 methylation at H3 lysine 36 (H3K36me). Cells devoid of Set2/H3K36me are hypersensitive to DNA-damaging agents and site-specific DSBs, fail to properly activate the DNA-damage checkpoint, and show genetic interactions with DSB-sensing and repair machinery. Set2/H3K36me3 is enriched at DSBs, and loss of Set2 results in altered chromatin architecture and inappropriate resection during G1 near break sites. Surprisingly, Set2 and RNA polymerase II are programmed for destruction after DSBs in a temporal manner--resulting in H3K36me3 to H3K36me2 transition that may be linked to DSB repair. Finally, we show a requirement of Set2 in DSB repair in transcription units--thus underscoring the importance of transcription-dependent H3K36me in DSB repair.

  12. Crystal structure of bis-(di-methyl-ammonium) hexa-aqua-nickel(II) bis-(sulfate) dihydrate.

    PubMed

    Held, Peter

    2014-11-01

    In the title salt, (C2H8N)2[Ni(H2O)6)](SO4)2·2H2O, the Ni(II) cation is located on a centre of inversion and exhibits a slightly distorted octa-hedral arrangement of water mol-ecules. The Ni-O bond lengths in the complex [Ni(H2O)6](2+) cation show a distribution as in the related Tutton salt (NH4)2[Ni(H2O)6](SO4)2, but are longer in average [2.056 (13) versus 2.037 (12) Å]. The noncoordinating water mol-ecules and di-methyl-ammonium cations connect the sulfate and [Ni(H2O)6](2+) octa-hedra via O-H⋯O and N-H⋯O hydrogen bonds from weak up to medium strength into a three-dimensional framework whereby the complex metal cations and sulfate anions are arranged in sheets parallel (001).

  13. Anti-Diabetic and Hepato-Renal Protective Effects of Ziyuglycoside II Methyl Ester in Type 2 Diabetic Mice

    PubMed Central

    Son, Dong Ju; Hwang, Seock Yeon; Kim, Myung-Hyun; Park, Un Kyu; Kim, Byoung Soo

    2015-01-01

    Type 2 diabetes is a metabolic disorder caused by abnormal carbohydrate metabolism, and closely associated with abnormal lipid metabolism and hepato-renal dysfunction. This study investigated the anti-diabetic and hepato-renal protective properties of ziyuglycoside I (ZG01) derivative on type 2 diabetes. ZG01 was isolated from roots of Sanguisorba officinalis and chemically modified by deglycosylation and esterification to obtained ziyuglycoside II methyl ester (ZG02-ME). Here, we showed that ZG02-ME has stronger anti-diabetic activity than the original compound (ZG01) through decreasing blood glucose, glycated hemoglobin (HbA1c), and insulin levels in a mouse model of type 2 diabetes (db/db mice). We further found that ZG02-ME treatment effectively ameliorated serum insulin, leptin and C-peptide levels, which are key metabolic hormones, in db/db mice. In addition, we showed that elevated basal blood lipid levels were decreased by ZG02-ME treatment in db/db mice. Furthermore, treatment of ZG02-ME significantly decreased serum AST, ALT, BUN, creatinine, and liver lipid peroxidation in db/db mice. These results demonstrated that compared to ZG01, chemically modified ZG02-ME possess improved anti-diabetic properties, and has hepato-renal protective activities in type 2 diabetes. PMID:26198246

  14. Site-specific methylation and acetylation of lysine residues in the C-terminal domain (CTD) of RNA polymerase II.

    PubMed

    Voss, Kirsten; Forné, Ignasi; Descostes, Nicolas; Hintermair, Corinna; Schüller, Roland; Maqbool, Muhammad Ahmad; Heidemann, Martin; Flatley, Andrew; Imhof, Axel; Gut, Marta; Gut, Ivo; Kremmer, Elisabeth; Andrau, Jean-Christophe; Eick, Dirk

    2015-01-01

    Dynamic modification of heptad-repeats with the consensus sequence Tyr1-Ser2-Pro3-Thr4-Ser5-Pro6-Ser7 of RNA polymerase II (RNAPII) C-terminal domain (CTD) regulates transcription-coupled processes. Mass spectrometry analysis revealed that K7-residues in non-consensus repeats of human RNAPII are modified by acetylation, or mono-, di-, and tri-methylation. K7ac, K7me2, and K7me3 were found exclusively associated with phosphorylated CTD peptides, while K7me1 occurred also in non-phosphorylated CTD. The monoclonal antibody 1F5 recognizes K7me1/2 residues in CTD and reacts with RNAPIIA. Treatment of cellular extracts with phosphatase or of cells with the kinase inhibitor flavopiridol unmasked the K7me1/2 epitope in RNAPII0, consistent with the association of K7me1/2 marks with phosphorylated CTD peptides. Genome-wide profiling revealed high levels of K7me1/2 marks at the transcriptional start site of genes for sense and antisense transcribing RNAPII. The new K7 modifications further expand the mammalian CTD code to allow regulation of differential gene expression.

  15. 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

    2016-08-08

    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. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Calcium/calmodulin-dependent protein kinase II is associated with the N-methyl-d-aspartate receptor

    PubMed Central

    Leonard, A. Soren; Lim, Indra A.; Hemsworth, Daniel E.; Horne, Mary C.; Hell, Johannes W.

    1999-01-01

    The molecular basis of long-term potentiation (LTP), a long-lasting change in synaptic transmission, is of fundamental interest because of its implication in learning. Usually LTP depends on Ca2+ influx through postsynaptic N-methyl-d-aspartate (NMDA)-type glutamate receptors and subsequent activation of Ca2+/calmodulin-dependent protein kinase II (CaMKII). For a molecular understanding of LTP it is crucial to know how CaMKII is localized to its postsynaptic targets because protein kinases often are targeted to their substrates by adapter proteins. Here we show that CaMKII directly binds to the NMDA receptor subunits NR1 and NR2B. Moreover, activation of CaMKIIα by stimulation of NMDA receptors in forebrain slices increase this association. This interaction places CaMKII not only proximal to a major source of Ca2+ influx but also close to α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)-type glutamate receptors, which become phosphorylated upon stimulation of NMDA receptors in these forebrain slices. Identification of the postsynaptic adapter for CaMKII fills a critical gap in the understanding of LTP because CaMKII-mediated phosphorylation of AMPA receptors is an important step during LTP. PMID:10077668

  17. Spectrophotometric, conductometric and thermal studies of Co(II), Ni(II) and Cu(II) complexes with 2-(2-hydroxynaphthylazo)-4-hydroxy-6-methyl-1,3-pyrimidine

    NASA Astrophysics Data System (ADS)

    Gaber, Mohamed; Mansour, Ikhlas A.; El-Sayed, Yousif S. Y.

    2007-10-01

    The electronic absorption spectra of 2-(2-hydroxynaphthylazo)-4-hydroxy-6-methyl-1,3-pyrimidine in pure organic solvents of different polarities and in buffer solutions of varying pH are studied. The important bands in the IR and the main signals in the 1H NMR spectra are assigned. The observed UV-vis absorption bands are assigned to the corresponding electronic transitions. The molecular stoichiometry, stability constant, absorption maximum, molar absorptivity and Sandell's sensitivity of the complexes are calculated. Obeyence to Beer's law and Ringbom optimum concentration ranges are also determined. The ability of using the titled azodye as metalochromic indicator in complexometric titrations was also studied. The effect of Co(II), Ni(II) and Cu(II) ions on the fluorescence of the azodye is also considered. The solid Cu(II) complexes of the titled azodye have been prepared and characterized by elemental, IR, UV-vis spectra as well as by conductometric and magnetic measurements. The data suggest square planar geometry for 1:1 and 1:2 (M:L) complexes. The thermal behaviour of the complexes has been studied. The kinetic parameters ( n, E, A, Δ H, Δ S and Δ G) of the thermal decomposition steps are computed using Coats-Redfern equations.

  18. 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.

  19. Chemical synthesis of methyl 6'-alpha-maltosyl-alpha-maltotrioside and its use for investigation of the action of starch synthase II.

    PubMed

    Damager, Iben; Olsen, Carl Erik; Blennow, Andreas; Denyer, Kay; Møller, Birger Lindberg; Motawia, Mohammed Saddik

    2003-01-20

    The branched pentasaccharide methyl 6'-alpha-maltosyl-alpha-maltotrioside was chemically synthesised and investigated as a primer for particulate starch synthase II (SSII) using starch granules prepared from the low-amylose pea mutant lam as the enzyme source. For chemical synthesis, the trichloroacetimidate activation method was used to synthesise methyl O-(2,3,4,6-tetra-O-benzyl-alpha-D-glucopyranosyl)-(1-->4)-O-(2,3,6-tri-O-benzyl-alpha-D-glucopyranosyl)-(1-->6)-O-[(2,3,4,6-tetra-O-benzyl-alpha-D-glucopyranosyl-(1-->4)]-O-(2,3-di-O-benzyl-alpha-D-glucopyranosyl)-(1-->4)-2,3,6-tri-O-benzyl-alpha-D-glucopyranoside, which was then debenzylated to provide the desired branched pentasaccharide methyl 6'-alpha-maltosyl-alpha-maltotrioside as documented by 1H and 13C NMR spectroscopy. Using a large excess of the maltoside, the pentasaccharide was tested as a substrate for starch synthase II (SSII). Both of the non-reducing ends of methyl 6'-alpha-maltosyl-alpha-maltotrioside were extended equally resulting in two hexasaccharide products in nearly equal amounts. Thus, SSII catalyses an equimolar and non-processive elongation reaction of this substrate. Accordingly, the presence of the alpha-1,6 linkages does not dictate a specific structure of the pentasaccharide in which only one of the two non-reducing ends are available for extension.

  20. Experimental Stark widths, shifts, and transition probabilities of several ArII lines

    SciTech Connect

    Aparicio, J. A.; Gigosos, M. A.; Mar, S.; Gonzalez, V. R.

    1997-01-05

    This paper is an extensive experimental contribution to the knowledge of ArII atomic parameters. This specie, which is very important for many astrophysical and industrial plasma diagnostics, has been extensively studied. However, there are still great differences in the experimental Stark widths and shifts coefficients, as well as a great lack of transition probability data, especially for lines coming from the very highly excited energy levels.

  1. Experimental Stark widths, shifts, and transition probabilities of several ArII lines

    SciTech Connect

    Aparicio, J.A.; Gigosos, M.A.; Mar, S.; Gonzalez, V.R.

    1997-01-01

    This paper is an extensive experimental contribution to the knowledge of ArII atomic parameters. This specie, which is very important for many astrophysical and industrial plasma diagnostics, has been extensively studied. However, there are still great differences in the experimental Stark widths and shifts coefficients, as well as a great lack of transition probability data, especially for lines coming from the very highly excited energy levels. {copyright} {ital 1997 American Institute of Physics.}

  2. 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

  3. Dichlorido{(E)-2,4,6-trimethyl-N-[phen­yl(2-pyridyl)methyl­idene]aniline-κ2 N,N′}palladium(II)

    PubMed Central

    Yang, Cheng-Hsien; Peng, Ya-Liu; Wang, Mei-Hua; Shih, Kuo-Chen; Hsueh, Mao-Lin

    2010-01-01

    The title complex, [PdCl2(C21H20N2)], contains a PdII atom in a slightly distorted square-planar coordination environment defined by two N atoms from one 2,4,6-trimethyl-N-[phen­yl(2-pyrid­yl)methyl­idene]aniline ligand and two Cl atoms, forming a five-membered ring (N—Pd—N—C—C). PMID:21579287

  4. 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

  5. Experimental Realization of Type-II Dirac Fermions in a PdTe_{2} Superconductor.

    PubMed

    Noh, Han-Jin; Jeong, Jinwon; Cho, En-Jin; Kim, Kyoo; Min, B I; Park, Byeong-Gyu

    2017-07-07

    A Dirac fermion in a topological Dirac semimetal is a quadruple-degenerate quasiparticle state with a relativistic linear dispersion. Breaking either time-reversal or inversion symmetry turns this system into a Weyl semimetal that hosts double-degenerate Weyl fermion states with opposite chiralities. These two kinds of quasiparticles, although described by a relativistic Dirac equation, do not necessarily obey Lorentz invariance, allowing the existence of so-called type-II fermions. The recent theoretical discovery of type-II Weyl fermions evokes the prediction of type-II Dirac fermions in PtSe_{2}-type transition metal dichalcogenides, expecting experimental confirmation. Here, we report an experimental realization of type-II Dirac fermions in PdTe_{2} by angle-resolved photoemission spectroscopy combined with ab initio band calculations. Our experimental finding shows the first example that has both superconductivity and type-II Dirac fermions, which turns the topological material research into a new phase.

  6. 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.

  7. 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.

  8. catena-Poly[[(4-methyl­benzoato-κO)manganese(II)]-μ-aqua-bis­(μ-4-methyl­benzoato-κ2 O:O′)[(4-methyl­benzoato-κO)manganese(II)]-bis­(μ-N,N-diethyl­nicotinamide)-κ2 N 3:O;O:N 3

    PubMed Central

    Hökelek, Tuncer; Dal, Hakan; Tercan, Barış; Çimen, Efdal; Necefoğlu, Hacali

    2010-01-01

    The asymmetric unit of the title complex, [Mn2(C8H7O2)4(C10H14N2O)2(H2O)]n, contains two crystallographically independent units. In each one, the MnII ions are bridged by two 4-methyl­benzoate (PMB) ligands and one water mol­ecule. In the crystal structure, each MnII ion is coordinated by three PMB ligands, one water mol­ecule and two symmetry-related N,N-diethyl­nicotinamide (DENA) ligands. Symmetry-related MnII ions are bridged by the N and O atoms of symmetry-related DENA ligands, forming polymeric chains parallel to [100]. The coord­ination environmnts for the MnII ions are slightly distorted octa­hedral. Intra­molecular O—H⋯O hydrogen bonds link bridging water mol­ecules to the carboxyl­ate O atoms of a neigh­boring polymeric chain. In the crystal structure, π–π contacts between benzene rings [centroid–centroid distance = 3.562 (1) Å] and weak C—H⋯π inter­actions are also observed. PMID:21587676

  9. The interaction of native DNA with Zn(II) and Cu(II) complexes of 5-triethyl ammonium methyl salicylidene orto-phenylendiimine.

    PubMed

    Silvestri, Arturo; Barone, Giampaolo; Ruisi, Giuseppe; Anselmo, Daniele; Riela, Serena; Liveri, Vincenzo Turco

    2007-05-01

    The interaction of native calf thymus DNA with the Zn(II) and Cu(II) complexes of 5-triethyl ammonium methyl salicylidene orto-phenylendiimine (ZnL(2+) and CuL(2+)), in 1 mM Tris-HCl aqueous solutions at neutral pH, has been monitored as a function of the metal complex-DNA molar ratio by UV absorption spectrophotometry, circular dichroism (CD) and fluorescence spectroscopy. The results support for an intercalative interaction of both ZnL(2+) and CuL(2+) with DNA, showing CuL(2+) an affinity of approximately 10 times higher than ZnL(2+). In particular, the values of the binding constant, determined by UV spectrophotometric titration, equal to 7.3x10(4) and 1.3x10(6)M(-1), for ZnL(2+) and CuL(2+), respectively, indicate the occurrence of a marked interaction with a binding size of about 0.7 in base pairs. The temperature dependence of the absorbance at 258 nm suggests that both complexes strongly increase the DNA melting temperature (Tm) already at metal complex-DNA molar ratios equal to 0.1. As evidenced by the quenching of the fluorescence of ethidium bromide-DNA solutions in the presence of increasing amounts of metal complex, ZnL(2+) and CuL(2+) are able to displace the ethidium cation intercalated into DNA. A tight ZnL(2+)-DNA and CuL(2+)-DNA binding has been also proven by the appearance, in both metal complex-DNA solutions, of a broad induced CD band in the range 350-450 nm. In the case of the CuL(2+)-DNA system, the shape of the CD spectrum, at high CuL(2+) content, is similar to that observed for psi-DNA solutions. Such result allowed us to hypothesize that CuL(2+) induces the formation of supramolecular aggregates of DNA in aqueous solutions.

  10. Experimental investigations of the influence of material and thickness on fracture under pure mode II loading

    NASA Astrophysics Data System (ADS)

    Dong, H.

    2010-06-01

    Experimental investigation to the effects of thickness and material on mode II fracture were performed. Tension-shear specimens made of aluminium alloy LC4CS and 7050-T7452 with thicknesses of 2, 4, 8 and 14 mm were used. All crack tip appearances and fracture profiles of the specimens were observed. Mode II fracture toughness were calculated. It is shown that material and thickness play an important role in mode II fracture. The fracture of LC4CS appears shear fracture under all kinds of thicknesses, however the fracture of 7050-T7452 is tensile fracture when thickness is larger or equal to 8mm, and shear initiation along the original crack plane, then turnaround and tensile failure when thickness is smaller than 8mm. Mode II fracture toughness is independent of thickness.

  11. SMAP: a streamlined methylation analysis pipeline for bisulfite sequencing.

    PubMed

    Gao, Shengjie; Zou, Dan; Mao, Likai; Zhou, Quan; Jia, Wenlong; Huang, Yi; Zhao, Shancen; Chen, Gang; Wu, Song; Li, Dongdong; Xia, Fei; Chen, Huafeng; Chen, Maoshan; Ørntoft, Torben F; Bolund, Lars; Sørensen, Karina D

    2015-01-01

    DNA methylation has important roles in the regulation of gene expression and cellular specification. Reduced representation bisulfite sequencing (RRBS) has prevailed in methylation studies due to its cost-effectiveness and single-base resolution. The rapid accumulation of RRBS data demands well designed analytical tools. To streamline the data processing of DNA methylation from multiple RRBS samples, we present a flexible pipeline named SMAP, whose features include: (i) handling of single-and/or paired-end diverse bisulfite sequencing data with reduced false-positive rates in differentially methylated regions; (ii) detection of allele-specific methylation events with improved algorithms; (iii) a built-in pipeline for detection of novel single nucleotide polymorphisms (SNPs); (iv) support of multiple user-defined restriction enzymes; (v) conduction of all methylation analyses in a single-step operation when well configured. Simulation and experimental data validated the high accuracy of SMAP for SNP detection and methylation identification. Most analyses required in methylation studies (such as estimation of methylation levels, differentially methylated cytosine groups, and allele-specific methylation regions) can be executed readily with SMAP. All raw data from diverse samples could be processed in parallel and 'packetized' streams. A simple user guide to the methylation applications is also provided.

  12. Crystal structure of bis-(di-methyl-ammonium) hexa-aqua-cobalt(II) bis-(sulfate) dihydrate.

    PubMed

    Held, Peter

    2015-04-01

    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 Ni(II) 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 mol-ecules and di-methyl-ammonium cations connect the sulfate tetrahedra and the [Co(H2O)6](2+) octa-hedron 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).

  13. Experimental and theoretical spectroscopic study and structural determination of nickel(II) tridentate Schiff base complexes.

    PubMed

    Kianfar, Ali Hossein; Farrokhpour, Hossein; Dehghani, Parin; Khavasi, Hamid Reza

    2015-11-05

    Some new complexes of [NiL(PR3)] (where L=(E)-1-[(2-amino-5-nitrophenyl)iminio-methyl]naphthalene-2-olate (L(1)), (E)-1-[(2-hydroxiphenyl)iminio-methyl]naphthalene-2-olate (L(2)), R=Bu and Ph) containing tridentate ONN and ONO Schiff bases were synthesized and characterized by IR, UV-Vis, (1)H-NMR spectroscopy and elemental analysis. The geometry of [NiL(1)(PBu3)] and [NiL(2)(PBu3)] complexes were determined by X-ray crystallography. It was indicated that the complexes have a square planar structure and four coordinates in the solid state. Theoretical calculations were also performed to optimize the structures of the ligands and complexes in the gas phase and ethanol solvent, separately to confirm the structures proposed by X-ray crystallography. In addition, UV-Visible and IR spectra of the complexes were calculated and compared with the corresponding experimental spectra to complete the experimental structural identification.

  14. Crystal structures of copper(II) nitrate complexes containing 4,4'-bipyridyl and halogen-substituted 2-[(2-hydroxyethylimino)methyl]phenols

    SciTech Connect

    Chumakov, Yu. M.; Tsapkov, V. I.; Petrenko, P. A.; Popovski, L. G.; Simonov, Yu. A.; Bocelli, G.; Gulea, A. P.

    2009-03-15

    The crystal structures of ({mu}-4,4'-bipyridyl)-di{l_brace}nitrato-2,4-dibromo-6-[(2-hydroxyethylimino)methyl] phenolo (1-)copper{r_brace} (I), ({mu}-4,4'-bipyridyl)-di{l_brace}nitrato-2,4-dichloro-6-[(2-hydroxyethylimino)methyl] phenolo(1-)copper{r_brace} (II), and ({mu}-4,4'-bipyridyl)-{l_brace}4-chloro-2-[(2-hydroxyethylimino)methyl]phenolo(2-) copper-nitrato-4-chloro-2-[(2-hydroxyethylimino)methyl]phenolo(1-)copper{r_brace} tetrahydrate (III) are determined. The crystal structures of compounds I and II contain binuclear complexes, in which each copper atom is coordinated by the singly deprotonated tridentate molecule of the corresponding azomethine, the monodentate nitrate ion, and bipyridyl that plays the role of a bridge between the central atoms. In the structures of compounds I and II, the coordination polyhedra of the copper atoms are slightly distorted tetragonal pyramids. The pyramid base is formed by the imine and bipyridyl nitrogen atoms and the phenol and alcohol oxygen atoms. The axial vertices of the pyramids are occupied by the oxygen atoms of the monodentate nitrato groups. The crystal structure of compound III involves tetranuclear complexes in which the coordination polyhedra of the central copper atoms are (4 + 1 + 1) bipyramids. The base of these bipyramids is formed by the imine and bipyridyl nitrogen atoms and the phenol and alcohol oxygen atoms. One apical vertex is occupied by the bridging phenol oxygen atom of the nearest complex. The sixth coordination site of the first copper atom is occupied by the chlorine atom of the salicylidene fragment of the neighboring complex related to the initial complex through the center of symmetry. In turn, the sixth coordination site of the second copper atom is occupied by the oxygen atom of the monodentate nitrato group.

  15. Effect of C5-methylation of cytosine on the photoreactivity of DNA: a joint experimental and computational study of TCG trinucleotides.

    PubMed

    Esposito, Luciana; Banyasz, Akos; Douki, Thierry; Perron, Marion; Markovitsi, Dimitra; Improta, Roberto

    2014-08-06

    DNA methylation, occurring at the 5 position of cytosine, is a natural process associated with mutational hotspots in skin tumors. By combining experimental techniques (optical spectroscopy, HPLC coupled to mass spectrometry) with theoretical methods (molecular dynamics, DFT/TD-DFT calculations in solution), we study trinucleotides with key sequences (TCG/T5mCG) in the UV-induced DNA damage. We show how the extra methyl, affecting the conformational equilibria and, hence, the electronic excited states, increases the quantum yield for the formation of cyclobutane dimers while reducing that of (6-4) adducts.

  16. Molecular structure of poly(methyl methacrylate) surface II: Effect of stereoregularity examined through all-atom molecular dynamics.

    PubMed

    Jha, Kshitij C; Zhu, He; Dhinojwala, Ali; Tsige, Mesfin

    2014-11-04

    Utilizing all-atom molecular dynamics (MD), we have analyzed the effect of tacticity and temperature on the surface structure of poly(methyl methacrylate) (PMMA) at the polymer-vacuum interface. We quantify these effects primarily through orientation, measured as the tilt with respect to the surface normal, and the surface number densities of the α-methyl, ester-methyl, carbonyl, and backbone methylene groups. Molecular structure on the surface is a complex interplay between orientation and number densities and is challenging to capture through sum frequency generation (SFG) spectroscopy alone. Independent quantification of the number density and orientation of chemical groups through all-atom MD presents a comprehensive model of stereoregular PMMA on the surface. SFG analysis presented in part I of this joint publication measures the orientation of molecules that are in agreement with MD results. We observe the ester-methyl groups as preferentially oriented, irrespective of tacticity, followed by the α-methyl and carbonyl groups. SFG spectroscopy also points to ester-methyl being dominant on the surface. The backbone methylene groups show a very broad angular distribution, centered along the surface plane. The surface number density ratios of ester-methyl to α-methyl groups show syndiotactic PMMA having the lowest value. Isotactic PMMA has the highest ratios of ester- to α-methyl. These subtle trends in the relative angular orientation and number densities that influence the variation of surface structure with tacticity are highlighted in this article. A more planar conformation of the syndiotactic PMMA along the surface (x-y plane) can be visualized through the trajectories from all-atom MD. Results from conformation tensor calculations for chains with any of their segments contributing to the surface validate the visual observation.

  17. 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.

  18. Experimental and theoretical studies on stability of new stabilizers for N-methyl-P-nitroaniline derivative in CMDB propellants.

    PubMed

    Tang, Qiufan; Fan, Xuezhong; Li, Jizhen; Bi, Fuqiang; Fu, Xiaolong; Zhai, Lianjie

    2017-04-05

    Although N-methyl-P-nitroaniline (MNA) was a quite effective stabilizer in composite modified double base (CMDB) propellants, it undergoes crystallization easily from nitroglycerin (NG) during storage. In order to improve its solubility in nitroglycerin (NG) and the stability in propellants, several new stabilizers including N-ethyl-p-nitroaniline (ENA), N-n-propyl-p-nitroaniline (n-PNA), N-i-propyl-p-nitroaniline (i-PNA), N-n-butyl-p-nitroaniline (n-BNA) and N-t-butyl-p-nitroaniline (t-BNA) were designed and synthesized to replace MNA by increasing the carbon chain length. The interaction between NG and different stabilizers was simulation by Materials Studio 5.5 and the stability and the high temperature stability performance of those new stabilizers in propellants were calculated by Gaussian 09. It was found that both the solubility of new stabilizers in NG and the stability and the high temperature stability performance of those in propellants were improved when the carbon chain length of substitution groups on nitrogen atom was increased. Thus, the n-BNA was a most potential stabilizer. Then all properties of the stabilizers were studied experimentally, which was agreement well with the theoretical analysis.

  19. Experimental design approach for the optimisation of a HPLC-fluorimetric method for the quantitation of the angiotensin II receptor antagonist telmisartan in urine.

    PubMed

    Torrealday, N; González, L; Alonso, R M; Jiménez, R M; Ortiz Lastra, E

    2003-08-08

    A high performance liquid chromatographic method with fluorimetric detection has been developed for the quantitation of the angiotensin II receptor antagonist (ARA II) 4-((2-n-propyl-4-methyl-6-(1-methylbenzimidazol-2-yl)-benzimidazol-1-yl)methyl)biphenyl-2-carboxylic acid (telmisartan) in urine, using a Novapak C18 column 3.9 x 150 mm, 4 microm. The mobile phase consisted of a mixture acetonitrile-phosphate buffer (pH 6.0, 5 mM) (45:55, v/v) pumped at a flow rate of 0.5 ml min(-1). Effluent was monitored at excitation and emission wavelengths of 305 and 365 nm, respectively. Separation was carried out at room temperature. Chromatographic variables were optimised by means of experimental design. A clean-up step was used for urine samples consisting of a solid-phase extraction procedure with C8 cartridges and methanol as eluent. This method proved to be accurate (RE from -12 to 6%), precise (intra- and inter-day coefficients of variation (CV) were lower than 8%) and sensitive enough (limit of quantitation (LOQ), ca. 1 microg l(-1)) to be applied to the determination of the active drug in urine samples obtained from hypertensive patients. Concentration levels of telmisartan at different time intervals (from 0 up to 36 h after oral intake) were monitored.

  20. Experimental and theoretical investigations of the kinetics and mechanism of the Cl + 4-hydroxy-4-methyl-2-pentanone reaction

    NASA Astrophysics Data System (ADS)

    Aslan, L.; Priya, A. Mano; Sleiman, C.; Zeineddine, M. N.; Coddeville, P.; Fittschen, C.; Ballesteros, B.; Canosa, A.; Senthilkumar, L.; El Dib, G.; Tomas, A.

    2017-10-01

    The reaction of 4-hydroxy-4-methyl-2-pentanone (4H4M2P) with Cl atoms was studied for the first time experimentally and theoretically. Relative kinetic measurements were carried out at room temperature and 1 bar of synthetic air/N2 in two different environmental chambers: a 300 L Teflon bag and a 16 L borosilicate glass cell. Reactants, reference compounds and products were monitored either by IR absorption or by GC-FID. Theoretical calculations were performed using the density functional theory method at BH&HLYP level of theory for twelve hydrogen abstraction pathways. The individual rate coefficients for the most favorable H-abstraction pathways were calculated by canonical variational theory using small curvature tunneling method at 298 K. An average experimental rate coefficient of (7.4 ± 0.6) × 10-11 cm3 molecule-1 s-1 was obtained at 298 K, in good agreement with the theoretical rate coefficient. The branching ratios for each reaction channel were evaluated theoretically from the individual rate coefficients of the identified channels. The H-atom abstracted on the -CH2 group appeared to be the dominant channel with a small barrier height. Formaldehyde, acetic acid, HCl, CO2 and CO were identified by IR as the major primary products. The obtained results are presented and discussed in terms of structure-reactivity relationships. A mechanism is suggested for the formation of the observed products. The atmospheric implications of the studied reaction are presented and more particularly, the lifetime of 4H4M2P towards Cl atoms is evaluated to be about 3 days.

  1. Unionid mussels as in situ biomonitors of elevated methyl mercury produced by experimental flooding of a small wetland

    SciTech Connect

    Malley, D.F.; Stewart, A.R.; Townsend, B.

    1995-12-31

    A wetland pond at the Experimental Lakes Area, northwestern Ontario, was experimentally flooded beginning in June 1993 to observe and understand the mechanisms of increased greenhouse gas production and methyl mercury (MeHg) production associated with flooding. The flooding resulted in a 20-fold increase in MeHg in the water from 0.1--0.3 ng/L to about 1.9 ng/L after one month. Unionid mussels, Anodonta grandis grandis, were introduced in cages in 1992 and 1993 into the wetland pond and into a reference, nonflooded wetland to determine if they can serve as biomonitors of increased [MeHg] associated with flooding. Upon retrieval after 48 or 90 days of caging, mussels were dissected into mantle, gill, foot, kidney and visceral remains (rest of body). The authors previously reported data on the visceral remains. Transferring mussels from their source lake to the wetlands was associated with no or small increases in MeHg and Hg in body parts. Mean contents of MeHg in mussels from the source and non-flooded wetlands were highest in the kidney (300--600 ng/g dry weight; 1,525% of total Hg) and lowest in the mantle (100--200 ng/g dry weight; 45--75 % of total Hg). Mussels retrieved after exposure to the elevated water MeHg of the flooded wetland for 90 d had increased MeHg in mantle, foot, and visceral remains; a marginal increase in kidney; and no change in gill. The increases in MeHg in body parts were reflected in increased total Hg. It is concluded that this mussel is useful for the monitoring of elevated MeHg in water bodies associated with flooding. Mantle and visceral remains were the body parts showing the proportionately largest increases in MeHg.

  2. Phosphorylated Pol II CTD recruits multiple HDACs, including Rpd3C(S), for methylation-dependent deacetylation of ORF nucleosomes

    PubMed Central

    Govind, Chhabi K.; Qiu, Hongfang; Ginsburg, Daniel S.; Ruan, Chun; Hofmeyer, Kimberly; Hu, Cuihua; Swaminathan, Venkatesh; Workman, Jerry L.; Li, Bing; Hinnebusch, Alan G.

    2010-01-01

    Methylation of histone H3 by Set1 and Set2 is required for deacetylation of nucleosomes in coding regions by histone deacetylase complexes (HDACs) Set3C and Rpd3C(S), respectively. We report that Set3C and Rpd3C(S) are co-transcriptionally recruited in the absence of Set1 and Set2, but in a manner stimulated by Pol II CTD kinase Cdk7/Kin28. Consistently, Rpd3C(S) and Set3C interact with Ser5-phosphorylated Pol II and histones in extracts, but only the histone interactions require H3 methylation. Moreover, reconstituted Rpd3C(S) binds specifically to Ser5-phosphorylated CTD peptides in vitro. Hence, whereas interaction with methylated H3 residues is required for Rpd3C(S) and Set3C deacetylation activities, their co-transcriptional recruitment is stimulated by the phosphorylated CTD. We further demonstrate that Rpd3, Hos2, and Hda1 have overlapping functions in deacetylating histones and suppressing co-transcriptional histone eviction. A strong correlation between increased acetylation and lower histone occupancy in HDA mutants implies that histone acetylation is a key determinant of nucleosome eviction. PMID:20670892

  3. TstI, a Type II restriction–modification protein with DNA recognition, cleavage and methylation functions in a single polypeptide

    PubMed Central

    Smith, Rachel M.; Pernstich, Christian; Halford, Stephen E.

    2014-01-01

    Type II restriction–modification systems cleave and methylate DNA at specific sequences. However, the Type IIB systems look more like Type I than conventional Type II schemes as they employ the same protein for both restriction and modification and for DNA recognition. Several Type IIB proteins, including the archetype BcgI, are assemblies of two polypeptides: one with endonuclease and methyltransferase roles, another for DNA recognition. Conversely, some IIB proteins express all three functions from separate segments of a single polypeptide. This study analysed one such single-chain protein, TstI. Comparison with BcgI showed that the one- and the two-polypeptide systems differ markedly. Unlike the heterologous assembly of BcgI, TstI forms a homotetramer. The tetramer bridges two recognition sites before eventually cutting the DNA in both strands on both sides of the sites, but at each site the first double-strand break is made long before the second. In contrast, BcgI cuts all eight target bonds at two sites in a single step. TstI also differs from BcgI in either methylating or cleaving unmodified sites at similar rates. The site may thus be modified before TstI can make the second double-strand break. TstI MTase acts best at hemi-methylated sites. PMID:24634443

  4. Phosphorylated Pol II CTD recruits multiple HDACs, including Rpd3C(S), for methylation-dependent deacetylation of ORF nucleosomes.

    PubMed

    Govind, Chhabi K; Qiu, Hongfang; Ginsburg, Daniel S; Ruan, Chun; Hofmeyer, Kimberly; Hu, Cuihua; Swaminathan, Venkatesh; Workman, Jerry L; Li, Bing; Hinnebusch, Alan G

    2010-07-30

    Methylation of histone H3 by Set1 and Set2 is required for deacetylation of nucleosomes in coding regions by histone deacetylase complexes (HDACs) Set3C and Rpd3C(S), respectively. We report that Set3C and Rpd3C(S) are cotranscriptionally recruited in the absence of Set1 and Set2, but in a manner stimulated by Pol II CTD kinase Cdk7/Kin28. Consistently, Rpd3C(S) and Set3C interact with Ser5-phosphorylated Pol II and histones in extracts, but only the histone interactions require H3 methylation. Moreover, reconstituted Rpd3C(S) binds specifically to Ser5-phosphorylated CTD peptides in vitro. Hence, whereas interaction with methylated H3 residues is required for Rpd3C(S) and Set3C deacetylation activities, their cotranscriptional recruitment is stimulated by the phosphorylated CTD. We further demonstrate that Rpd3, Hos2, and Hda1 have overlapping functions in deacetylating histones and suppressing cotranscriptional histone eviction. A strong correlation between increased acetylation and lower histone occupancy in HDA mutants implies that histone acetylation is important for nucleosome eviction. Copyright 2010 Elsevier Inc. All rights reserved.

  5. Crystal structure of hexa-kis-(di-methyl-formamide-κO)manganese(II) deca-kis-(di-methyl-formamide)-1κ(5) O,2κ(5) O-[μ-octa-deca-tungstodiphosphato(V)-κO:κO']dimanganate(II) di-methyl-formamide disolvate.

    PubMed

    Dhifallah, Fatma; Belkhiria, Mohamed Salah

    2016-06-01

    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 Mn(II) octa-hedral complexes. In the complex anion [{Mn(dmf)5}2(μ-P2W18O62)](2-), located around a twofold rotation axis, the Mn(II) ions are coordinated by five O atoms from di-methyl-formamide (dmf) ligands and to a terminal O atom from the [P2W18O62](6-) polyanion. Another Mn(II) 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.

  6. 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

  7. DNA isolation method is a source of global DNA methylation variability measured with LUMA. Experimental analysis and a systematic review.

    PubMed

    Soriano-Tárraga, Carolina; Jiménez-Conde, Jordi; Giralt-Steinhauer, Eva; Ois, Angel; Rodríguez-Campello, Ana; Cuadrado-Godia, Elisa; Fernández-Cadenas, Israel; Montaner, Joan; Lucas, Gavin; Elosua, Roberto; Roquer, Jaume

    2013-01-01

    In DNA methylation, methyl groups are covalently bound to CpG dinucleotides. However, the assumption that methyl groups are not lost during routine DNA extraction has not been empirically tested. To avoid nonbiological associations in DNA methylation studies, it is essential to account for potential batch effect bias in the assessment of this epigenetic mechanism. Our purpose was to determine if the DNA isolation method is an independent source of variability in methylation status. We quantified Global DNA Methylation (GDM) by luminometric methylation assay (LUMA), comparing the results from 3 different DNA isolation methods. In the controlled analysis (n = 9), GDM differed slightly for the same individual depending on extraction method. In the population analysis (n = 580) there were significant differences in GDM between the 3 DNA isolation methods (medians, 78.1%, 76.5% and 75.1%; p<0.001). A systematic review of published data from LUMA GDM studies that specify DNA extraction methods is concordant with our findings. DNA isolation method is a source of GDM variability measured with LUMA. To avoid possible bias, the method used should be reported and taken into account in future DNA methylation studies.

  8. 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.

  9. Construction of two Cd(II) complexes by flexible adipic acid plus 2-((benzoimidazol-yl)methyl)-1H-tetrazole ligand

    NASA Astrophysics Data System (ADS)

    Duan, Wanlu; Zhang, Yuhong; Wang, Xiuxiu; Meng, Xiangru

    2015-10-01

    Two new complexes with the formulas [Cd(bimt)(adi)]n (1) and {[Cd(bimt)(adi)0.5Br]·H2O}n (2) were synthesized through reactions of 2-((benzoimidazol-yl)methyl)-1H-tetrazole (bimt) with Cd(II) salts in the presence of adipic acid (H2adi). Single crystal X-ray analysis reveals that complex 1 shows a 1D chain structure in which adipate ligand coordinates to Cd(II) ions with μ3-bridging mode. Complex 2 displays a 2D layer structure with 4-connected (44·62) topology in which adipate ligand coordinates to Cd(II) ions with μ2-bridging mode. These results reveal that the versatile coordination modes of adipate ligands play an important role in controlling the structures of the complexes. In addition, their IR spectra, element analyses, PXRD patterns and luminescent properties are investigated.

  10. 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.

  11. Crystal structure of tetra-aqua-bis-(thio-cyanato-κN)nickel(II)-2,5-di-methyl-pyrazine (1/4).

    PubMed

    Suckert, Stefan; Wriedt, Mario; Jess, Inke; Näther, Christian

    2015-02-01

    In the crystal structure of the title compound, [Ni(NCS)2(H2O)4]·4C6H8N2, the Ni(II) cations are coordinated by four water ligands and two trans-coordinated terminally N-bonded thio-cyanate anions in a slightly distorted octa-hedral geometry. The asymmetric unit consists of a Ni(2+) cation located on a centre of inversion, two water mol-ecules and one thio-cyanate ligand, as well as two uncoordinated 2,5-di-methyl-pyrazine ligands in general positions. In the crystal, discrete complex mol-ecules are linked into a three-dimensional network by O-H⋯N hydrogen bonding between the water H atoms and the 2,5-di-methyl-pyrazine N atoms.

  12. Critical Review of Experimental Studies of the Be II Core-Excited Level System

    NASA Astrophysics Data System (ADS)

    Kramida, A. E.

    1998-01-01

    All published experimental data on the spectrum of the core-excited term system of the Be+ ion are critically compiled and analysed on the basis of Hartree-Fock calculations and computer-aided spectrum-identification and level-optimization programs. As a result, 49 core-excited terms in Be II are firmly established. Another 44 terms need further confirmation. More than 100 spectral lines belonging to transitions in the Be II core-excited term system are compiled. Spectral regions 80-105Å and 580-5200Å are covered. 13 new assignments are made, and 33 old assignments are changed. 44 previously unobserved spectral lines are predicted, including 10 intersystem lines. Several experimental and theoretical problems are outlined.

  13. The primary structures of the Archaeon Halobacterium salinarium blue light receptor sensory rhodopsin II and its transducer, a methyl-accepting protein.

    PubMed

    Zhang, W; Brooun, A; Mueller, M M; Alam, M

    1996-08-06

    Recently, a large family of transducer proteins in the Archaeon Halobacterium salinarium was identified. On the basis of the comparison of the predicted structural domains of these transducers, three distinct subfamilies of transducers were proposed. Here we report isolation, complete gene sequences, and analysis of the encoded primary structures of transducer gene htrII, a member of family B, and its blue light receptor gene (sopII) of sensory rhodopsin II (SRII). The start codon ATG of the 714-bp sopII gene is one nucleotide beyond the termination codon TGA of the 2298-bp htrII gene. The deduced protein sequence of HtrII predicts a eubacterial chemotaxis transducer type with two hydrophobic membrane-spanning segments connecting sizable domains in the periplasm and cytoplasm. HtrII has a common feature with HtrI, the sensory rhodopsin I transducer; like HtrI, HtrII possesses a hydrophilic loop structure just after the second transmembrane segment. The C-terminal 299 residues (765 amino acid residues total) of HtrII show strong homology to the signaling and methylation domain of eubacterial transducer Tsr. The hydropathy plot of the primary structure of SRII indicates seven membrane-spanning alpha-helical segments, a characteristic feature of retinylidene proteins ("rhodopsins") from a widespread family of photoactive pigments. SRII shows high identity with SRI (42%), bacteriorhodopsin (BR) (32%), and halorhodopsin (24%). The crucial positions for retinal binding sites in these proteins are nearly identical, with the exception of Met-118 (numbering according to the mature BR sequence), which is replaced by Val in SRII. In BR, residues Asp-85 and Asp-96 are crucial in proton pumping. In SRII, the position corresponding to Asp-85 in BR is conserved, but the corresponding position of Asp-96 is replaced by an aromatic Tyr. Coexpression of the htrII and sopII genes restores SRII phototaxis to a mutant (Pho81) that contains a deletion in the htrI/sopI and insertion in

  14. Fine-tuning of histone H3 Lys4 methylation during pseudohyphal differentiation by the CDK submodule of RNA polymerase II.

    PubMed

    Law, Michael J; Ciccaglione, Kerri

    2015-02-01

    Transcriptional regulation is dependent upon the interactions between the RNA pol II holoenzyme complex and chromatin. RNA pol II is part of a highly conserved multiprotein complex that includes the core mediator and CDK8 subcomplex. In Saccharomyces cerevisiae, the CDK8 subcomplex, composed of Ssn2p, Ssn3p, Ssn8p, and Srb8p, is thought to play important roles in mediating transcriptional control of stress-responsive genes. Also central to transcriptional control are histone post-translational modifications. Lysine methylation, dynamically balanced by lysine methyltransferases and demethylases, has been intensively studied, uncovering significant functions in transcriptional control. A key question remains in understanding how these enzymes are targeted during stress response. To determine the relationship between lysine methylation, the CDK8 complex, and transcriptional control, we performed phenotype analyses of yeast lacking known lysine methyltransferases or demethylases in isolation or in tandem with SSN8 deletions. We show that the RNA pol II CDK8 submodule components SSN8/SSN3 and the histone demethylase JHD2 are required to inhibit pseudohyphal growth-a differentiation pathway induced during nutrient limitation-under rich conditions. Yeast lacking both SSN8 and JHD2 constitutively express FLO11, a major regulator of pseudohyphal growth. Interestingly, deleting known FLO11 activators including FLO8, MSS11, MFG1, TEC1, SNF1, KSS1, and GCN4 results in a range of phenotypic suppression. Using chromatin immunoprecipitation, we found that SSN8 inhibits H3 Lys4 trimethylation independently of JHD2 at the FLO11 locus, suggesting that H3 Lys4 hypermethylation is locking FLO11 into a transcriptionally active state. These studies implicate the CDK8 subcomplex in fine-tuning H3 Lys4 methylation levels during pseudohyphal differentiation. Copyright © 2015 by the Genetics Society of America.

  15. The interactions of methyl tert-butyl ether on high silica zeolites: a combined experimental and computational study.

    PubMed

    Sacchetto, V; Gatti, G; Paul, G; Braschi, I; Berlier, G; Cossi, M; Marchese, L; Bagatin, R; Bisio, C

    2013-08-28

    In this work, the interactions of methyl tert-butyl ether (MTBE) on different dealuminated high silica zeolites were studied by means of both experimental and computational approaches. Zeolites with different textural and surface features were selected as adsorbents and the effect of their physico-chemical properties (i.e. pore size architecture and type and amount of surface OH sites) on sorption capacity were studied. High silica mordenite (MOR) and Y zeolites (both with a SiO2/Al2O3 ratio of 200) and ZSM-5 solid (SiO2/Al2O3 ratio of 500) were selected as model sorbents. By combining FTIR and SS-NMR (both (1)H and (13)C CPMAS NMR) spectroscopy it was possible to follow accurately the MTBE adsorption process on highly defective MOR characterized by a high concentration of surface SiOH groups. The adsorption process is found to occur in different steps and to involve isolated silanol sites, weakly interacting silanols, and the siloxane network of the zeolite, respectively. H-bonding and van der Waals interactions occurring between the mordenite surface and MTBE molecules were modeled by DFT calculations using a large cluster of the MOR structure where two adjacent side-pockets were fused in a large micropore to simulate a dealumination process leading to silanol groups. This is the locus where MTBE molecules are more strongly bound and stabilized. FTIR spectroscopy and gravimetric measurements allowed determination of the interaction strength and sorption capacities of all three zeolites. In the case of both Y and MOR zeolites, medium-weak H-bonding with isolated silanols (both on internal and external zeolite surfaces) and van der Waals interactions are responsible for MTBE adsorption, whereas ZSM-5, in which a negligible amount of surface silanol species is present, displays a much lower amount of adsorbed MTBE retained mainly through van der Waals interactions with zeolite siloxane network.

  16. 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.

  17. Methionine adenosyltransferase II-dependent histone H3K9 methylation at the COX-2 gene locus.

    PubMed

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

    2013-05-10

    MATII biosynthesizes AdoMet, which supplies methyl group for methylation of molecules, including histone. MATII interacts with histone methyltransferase SETDB1 and inhibits COX-2 gene expression. AdoMet synthesis and histone methylation are coupled on chromatin by a physical interaction of MATII and SETDB1 at the MafK target genes. MATII may be important for both gene-specific and epigenome-wide regulation of histone methylation. 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.

  18. 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.

  19. Synthesis, spectroscopic and DNA binding ability of Co(II), Ni(II), Cu(II) and Zn(II) complexes of Schiff base ligand (E)-1-(((1H-benzo[d]imidazol-2-yl)methylimino)methyl)naphthalen-2-ol. X-ray crystal structure determination of cobalt (II) complex.

    PubMed

    Yarkandi, Naeema H; El-Ghamry, Hoda A; Gaber, Mohamed

    2017-06-01

    A novel Schiff base ligand, (E)-1-(((1H-benzo[d]imidazol-2-yl)methylimino)methyl)naphthalen-2-ol (HL), has been designed and synthesized in addition to its metal chelates [Co(L)2]·l2H2O, [Ni(L)Cl·(H2O)2].5H2O, [Cu(L)Cl] and [Zn(L)(CH3COO)]. The structures of the isolated compounds have been confirmed and identified by means of different spectral and physicochemical techniques including CHN analysis, (1)H &(13)C NMR, mass spectral analysis, molar conductivity measurement, UV-Vis, infrared, magnetic moment in addition to TGA technique. The infrared spectral results ascertained that the ligand acts as monobasic tridentate binding to the metal centers via deprotonated hydroxyl oxygen, azomethine and imidazole nitrogen atoms. The UV-Vis, magnetic susceptibility and molar conductivity data implied octahedral geometry for Co(II) & Ni(II) complexes, tetrahedral for Zn(II) complex and square planar for Cu(II) complex. X-ray structural analysis of Co(II) complex 1 has been reported and discussed. Moreover, the type of interaction between the ligand & its complexes towards salmon sperm DNA (SS-DNA) has been examined by the measurement of absorption spectra and viscosity which confirmed that the ligand and its complexes interact with DNA via intercalation interaction as concluded from the values of binding constants (Kb). Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Bis(2-amino-6-methyl-pyrimidin-1-ium-4-olate-κN,O)bis-(nitrato-κO,O')cadmium(II).

    PubMed

    Kaabi, Kamel; El Glaoui, Meher; Pereira Silva, P S; Ramos Silva, M; Ben Nasr, Cherif

    2010-05-08

    In the title compound, [Cd(NO(3))(2)(C(5)H(7)N(3)O)(2)], the Cd(II) atom is eight-coordinated by two amine N atoms and two O atoms from two zwitterionic, biodentate 2-amino-6-methyl-pyrimidin-1-ium-4-olate ligands and by four O atoms from two nitrate groups. Intra-molecular N-H⋯O hydrogen bonds occur. The crystal packing is stabilized by inter-molecular N-H⋯O and C-H⋯O hydrogen bonds, two of which are bifurcated, between the nitrate anions and the organic groups.

  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. A New Long-Lasting Indoor Residual Formulation of the Organophosphate Insecticide Pirimiphos Methyl for Prolonged Control of Pyrethroid-Resistant Mosquitoes: An Experimental Hut Trial in Benin

    PubMed Central

    Rowland, Mark; Boko, Pelagie; Odjo, Abibatou; Asidi, Alex; Akogbeto, Martin; N’Guessan, Raphael

    2013-01-01

    Background Indoor residual spraying (IRS) is widely used for malaria transmission control in sub-Saharan Africa. Resistance to pyrethroids in the mosquito Anopheles gambiae is a growing problem. There is an urgent need to develop long-lasting alternative insecticides to reduce selection pressure for pyrethroid resistance and to provide control with a single IRS application in countries with long transmission seasons. Methods Two capsule suspension formulations (CS) of the organophosphate pirimiphos methyl were evaluated as IRS treatments in experimental huts in an area of Benin where the mosquitoes Anopheles gambiae and Culex quinquefasciatus are resistant to pyrethroids but susceptible to organophosphates. The CS formulations were tested alongside an emulsifiable concentrate (EC) formulation of pirimiphos methyl and a CS formulation of the pyrethroid lambdacyhalothrin. Results The two CS formulations of pirimiphos methyl gave prolonged control of An. gambiae and Cx. quinquefasciatus. In cement huts application rates of 0.5 g/m2 induced high mortality of An. gambiae for almost a year: overall mortality rates 87% (95% CI 82–91%) and 92% (95% CI 88–94%). In mud huts application rates of 1 g/m2 induced high mortality of An. gambiae for 10 months: overall mortality rates 75% (95% CI 69–81%) and 76% (95% CI 68–83%). The EC formulation of pirimiphos methyl failed to control An. gambiae two months after spraying. The pyrethroid lambdacyhalothrin demonstrated prolonged residual activity in bioassay tests but failed to control pyrethroid resistant An. gambiae that entered the huts. Pirimiphos methyl CS was highly active against Culex quinquefasciatus and gave control for 10 months in cement huts and 6 months in mud huts. Conclusion Pirimiphos methyl CS (Actellic 300 CS) applied at 1 g/m2 shows great promise for providing prolonged control of pyrethroid-resistant An gambiae and for delaying pyrethroid resistance. An alternative to DDT, giving year-round transmission

  3. Bis(η5-penta­methyl­cyclo­penta­dien­yl)cobalt(II)

    PubMed Central

    Clark, Meghan M.; Brennessel, William W.; Holland, Patrick L.

    2009-01-01

    The crystal structure of the title compound, deca­methyl­cobaltocene, [Co(C10H15)2], has been determined. High-quality single crystals were grown from a cold saturated hexa­methyl­disiloxane solution. The structure is related to the manganese and iron analogs. The molecule has D 5d symmetry, with the Co atom in a crystallographic 2/m position. The cobalt–centroid(C5) distance is 1.71Å and the centroid(C5)–Co–centroid(C5) angle is 180°, by symmetry. PMID:21582340

  4. 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 Ͽ⿿Ͽ interaction and higher charge carrier mobility.

  5. 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).

  6. Completion of Experimental Breeder Reactor-II Sodium Processing at Argonne National Laboratory

    SciTech Connect

    McDermott, Mary D.; Griffin, Charles D.; Baird, Daniel K.; Baily, Carl E.; Michelbacher, John A.; Rosenberg, Kenneth E.; Henslee, S. Paul

    2002-07-01

    The Experimental Breeder Reactor - II (EBR-II) at Argonne National Laboratory - West (ANL-W) was shutdown in September 1994 as mandated by the United States Department of Energy. Located in eastern Idaho, this sodium-cooled reactor had been in service since 1964, and was a test facility for fuels development, materials irradiation, system and control theory tests, and hardware development. The EBR-II termination activities began in October 1994, with the reactor being maintained in an industrially and radiologically safe condition for decommissioning. With the shutdown of EBR-II, its sodium coolant became a waste necessitating its reaction to a disposal form. A Sodium Process Facility (SPF), designed to convert sodium to 50 wt% sodium hydroxide, existed at the ANL-W site, but had never been operated. The SPF was upgraded to current standards and codes, and then modified in 1998 to convert the sodium to 70 wt% sodium hydroxide, a substance that solidifies at 65 deg. C (150 deg. F) and is acceptable for burial as low level radioactive waste in Idaho. In December 1998, the SPF began operations. Working with sodium and highly concentrated sodium hydroxide presented some unique operating and maintenance conditions. Several lessons were learned throughout the operating period. Processing of the 330 m{sup 3} (87,000 gallons) of EBR-II primary sodium, 50 m{sup 3} (13,000 gallons) of EBR-II secondary sodium, and 290 m{sup 3} (77,000 gallons) of Fermi-1 primary sodium was successfully completed in March 2001, ahead of schedule and within budget. (authors)

  7. Experimental observation of topological Fermi arcs in type-II Weyl semimetal MoTe2

    NASA Astrophysics Data System (ADS)

    Deng, Ke; Wan, Guoliang; Deng, Peng; Zhang, Kenan; Ding, Shijie; Wang, Eryin; Yan, Mingzhe; Huang, Huaqing; Zhang, Hongyun; Xu, Zhilin; Denlinger, Jonathan; Fedorov, Alexei; Yang, Haitao; Duan, Wenhui; Yao, Hong; Wu, Yang; Fan, Shoushan; Zhang, Haijun; Chen, Xi; Zhou, Shuyun

    2016-12-01

    Weyl semimetal is a new quantum state of matter hosting the condensed matter physics counterpart of the relativistic Weyl fermions originally introduced in high-energy physics. The Weyl semimetal phase realized in the TaAs class of materials features multiple Fermi arcs arising from topological surface states and exhibits novel quantum phenomena, such as a chiral anomaly-induced negative magnetoresistance and possibly emergent supersymmetry. Recently it was proposed theoretically that a new type (type-II) of Weyl fermion that arises due to the breaking of Lorentz invariance, which does not have a counterpart in high-energy physics, can emerge as topologically protected touching between electron and hole pockets. Here, we report direct experimental evidence of topological Fermi arcs in the predicted type-II Weyl semimetal MoTe2 (refs ,,). The topological surface states are confirmed by directly observing the surface states using bulk- and surface-sensitive angle-resolved photoemission spectroscopy, and the quasi-particle interference pattern between the putative topological Fermi arcs in scanning tunnelling microscopy. By establishing MoTe2 as an experimental realization of a type-II Weyl semimetal, our work opens up opportunities for probing the physical properties of this exciting new state.

  8. Overview of the TIBER II (Tokamak Ignition/Burn Experimental Reactor) design

    SciTech Connect

    Henning, C.D.; Logan, B.G.

    1987-10-16

    The TIBER II Tokamak Ignition/Burn Experimental Reactor design is the result of efforts by numerous people and institutions, including many fusion laboratories, universities, and industries. While subsystems will be covered extensively in other reports, this overview will attempt to place the work in perspective. Major features of the design are compact size, low cost, and steady-state operation. These are achieved through plasma shaping and innovative features such as radiation tolerant magnets and optimized shielding. While TIBER II can operate in a pulsed mode, steady-state is preferred for nuclear testing. Current drive is achieved by a combination of lower hybrid and neutral beams. In addition, 10 MW of ECR is added for disruption control and current drive profiling. The TIBER II design has been the US option in preparation for the International Thermonuclear Experimental Reactor (ITER). Other equivalent national designs are the NET in Europe, the FER in Japan and the OTR in the USSR. These designs will help set the basis for the new international design effort. 9 refs.

  9. {(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

  10. catena-Poly[[tetra-μ-formato-κ(8) O:O'-dicopper(II)]-μ-hexa-methyl-ene-tetra-mine-κ(2) N (1):N (5)].

    PubMed

    Cao, Jianfang; Huang, Ziping; Cao, Changnian; Cheng, Chunchun; Sun, Chunyan

    2013-11-30

    In the title polymeric compound, [Cu2(HCO2)4(C6H12N4)] n , the Cu(II) atom is five-coordinated in a square-pyramidal geometry that is defined by four O atoms from four formate ligands and one N atom from a hexa-methyl-ene-tetra-mine ligand. The two Cu(II) atoms are separated by 2.6850 (7) Å, and together with the four formate ligands they form a paddle-wheel unit. The hexa-mine ligand uses only two of its four N atoms to link Cu2 cluster units, affording a zigzag chain running along the b-axis direction. The hexa-mine ligand lies on a mirror plane.

  11. Crystal structure of high-spin tetra-aqua-bis-(2-chloro-pyrazine-κN (4))iron(II) bis-(4-methyl-benzene-sulfonate).

    PubMed

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

    2015-07-01

    The title salt, [Fe(II)(C4H3ClN2)2(H2O)4](C7H7O3S)2, contains a complex cation with point group symmetry 2/m. The high-spin Fe(II) cation is hexa-coordinated by four symmetry-related water and two N-bound 2-chloro-pyrazine mol-ecules in a trans arrangement, forming a distorted FeN2O4 octa-hedron. The three-dimensional supra-molecular structure is supported by inter-molecular O-H⋯O hydrogen bonds between the complex cations and tosyl-ate anions, and additional π-π inter-actions between benzene and pyrazine rings. The methyl H atoms of the tosyl-ate anion are equally disordered over two positions.

  12. Di-u-hydroxo-bis{(acetonitrile)dibenzyl(6-methyl-2-pyridylmethyl)-amine-kappa2N,N]copper(II)} bis(perchlorate).

    PubMed

    Rojas, Dario; García, Ana María; Manzur, Jorge; Vega, Andrés

    2005-02-01

    The title compound corresponds to a copper(II) dimer, [Cu2(OH)2(C2H3N)2(C21H22N2)2](ClO4)2, where the metal centres are mu2-bridged by hydroxo groups. The coordination of each copper(II) centre is a slightly distorted square-based pyramid, with two N atoms from dibenzyl(6-methyl-2-pyridylmethyl)amine (BiBzMePMA) and two hydroxo O atoms occupying the basal positions, and the acetonitrile N atom at the apical position. The dimer is centrosymmetric, with a crystallographic inversion centre midway between the two Cu atoms [Cu...Cu = 2.9522 (9) A].

  13. Experimental and calculational analyses of actinide samples irradiated in EBR-II

    SciTech Connect

    Gilai, D.; Williams, M.L.; Cooper, J.H.; Laing, W.R.; Walker, R.L.; Raman, S.; Stelson, P.H.

    1982-10-01

    Higher actinides influence the characteristics of spent and recycled fuel and dominate the long-term hazards of the reactor waste. Reactor irradiation experiments provide useful benchmarks for testing the evaluated nuclear data for these actinides. During 1967 to 1970, several actinide samples were irradiated in the Idaho EBR-II fast reactor. These samples have now been analyzed, employing mass and alpha spectrometry, to determine the heavy element products. A simple spherical model for the EBR-II core and a recent version of the ORIGEN code with ENDF/B-V data were employed to calculate the exposure products. A detailed comparison between the experimental and calculated results has been made. For samples irradiated at locations near the core center, agreement within 10% was obtained for the major isotopes and their first daughters, and within 20% for the nuclides up the chain. A sensitivity analysis showed that the assumed flux should be increased by 10%.

  14. 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.

  15. 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

    2011-09-30

    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.

  16. 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.

  17. 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.

  18. Experimental and theoretical studies of the molecular structure of 7-Methyl-3-[(3-methyl-3-mesityl-cyclobutyl]-5-phenyl-5H-thiazolo[3,2-α]pyrimidine-6-carboxylic acid ethyl ester

    NASA Astrophysics Data System (ADS)

    Acar, Betül; Yilmaz, Ibrahim; Çalışkan, Nezihe; Cukurovali, Alaaddin

    2017-07-01

    In this work, the title molecule, 7-Methyl-3-[(3-methyl-3-mesityl-cyclobutyl]-5-phenyl-5H-thiazolo[3,2-α]pyrimidine-6-carboxylic acid ethyl ester (C30H34N2O2S1), was synthesized and characterized by FT-IR spectroscopy and single crystal X-ray diffraction. The compound crystallizes in the triclinic space group P21/c. with Z = 4, a = 14.1988(6), b = 19.0893(5), c = 10.1325(4) Å, V = 2674.56(17) A3. The optimized structure parameters of the studied molecule was determined theoretically using HF/6-31G(d) and B3LYP/6-31G(d) methods for ground state, and compared with previously reported experimental findings. The calculated harmonic vibrational frequencies are scaled and they are compared with experimental frequencies obtained by FT-IR spectra. The electronic properties, such as HOMO and LUMO energies, and molecular electrostatic potential (MEP) are also performed.

  19. A new three-dimensional manganese(II) coordination polymer based on the 1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene ligand.

    PubMed

    Lu, Xin Hua; Zhong, Kai Long

    2016-11-01

    The self-assembly of coordination polymers and the crystal engineering of metal-organic coordination frameworks have attracted great interest, but it is still a challenge to predict and control the compositions and structures of the complexes. Employing multidentate organic ligands and suitable metal ions to construct inorganic-organic hybrid materials through metal-ligand coordination and hydrogen-bonding interactions has become a major strategy. Recently, imidazole-containing multidentate ligands that contain an aromatic core have received much attention. A new three-dimensional Mn(II) coordination polymer based on 1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene, namely poly[(ethane-1,2-diol-κO)(μ-sulfato-κ(2)O:O'){μ3-1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene-κ(3)N:N':N''}manganese(II)], [Mn(SO4)(C18H18N6)(C2H6O2)]n, was synthesized and characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. Crystal structural analysis shows that there are two kinds of crystallographically independent Mn(II) centres, each lying on a centrosymmetric position and having a similar six-coordinated octahedral structure. One is coordinated by four N atoms from four 1,3,5-tris[(1H-imidazol-1-yl)methyl]benzene (timb) ligands and two O atoms from two different bridging sulfate anions. The second is surrounded by two timb N atoms and four O atoms, two from sulfate anions and two from two ethane-1,2-diol ligands. The tripodal timb ligand bridges neighbouring Mn(II) centres to generate a two-dimensional layered structure running parallel to the ab plane. Adjacent layers are further bridged by sulfate anions, resulting in a three-dimensional structure with 3,4,6-c topology. Thermogravimetric analysis of the title polymer shows that it is stable up to 533 K. The first weight loss between 533 and 573 K corresponds to the release of coordinated ethane-1,2-diol molecules, and further decomposition occurred at 648 K.

  20. Synthesis, experimental and theoretical characterization of palladium(II) and platinum(II) saccharinate complexes with 2-(2-pyridyl)benzimidazole

    NASA Astrophysics Data System (ADS)

    Guney, Emel; Kaya, Yunus; Yilmaz, Veysel T.; Gumus, Sedat

    2011-09-01

    New palladium(II) and platinum(II) complexes of saccharinate (sac) with 2-(2-pyridyl)benzimidazole (pybim) have been synthesized and characterized by elemental analysis and spectroscopic techniques. From the experimental studies, these complexes were formulated as [Pd(pybim)(sac) 2] ( 1), and [Pt(pybim)(sac) 2]·4H 2O ( 2). The ground-state geometries of both complexes were optimized using density functional theory (DFT) methods at the B3LYP level. A bidentate pybim ligand together with two N-coordinated sac ligands form the square-planar MN 4 coordination geometry around the palladium(II) and platinum(II) ions. The calculated IR and UV-vis spectral data have been correlated to the experimental results. Thermal analysis data support the molecular structures of both complexes.

  1. Direct angiotensin II type 2 receptor stimulation in Nω-nitro-L-arginine-methyl ester-induced hypertension: the effect on pulse wave velocity and aortic remodeling.

    PubMed

    Paulis, Ludovit; Becker, Sophie T R; Lucht, Kristin; Schwengel, Katja; Slavic, Svetlana; Kaschina, Elena; Thöne-Reineke, Christa; Dahlöf, Björn; Baulmann, Johannes; Unger, Thomas; Steckelings, U Muscha

    2012-02-01

    Pulse wave velocity (PWV), a direct marker of arterial stiffness, is an independent cardiovascular risk factor. Although the angiotensin II type 1 receptor blockade belongs to major antihypertensive and cardioprotective therapies, less is known about the effects of long-term stimulation of the angiotensin II type 2 receptor. Previously, compound 21, a selective nonpeptide angiotensin II type 2 receptor agonist improved the outcome of myocardial infarction in rats along with anti-inflammatory properties. We investigated whether compound 21 alone or in combination with angiotensin II type 1 receptor blockade by olmesartan medoxomil could prevent PWV increase and aortic remodeling in N(ω)-nitro-L-arginine-methyl ester (L-NAME)-induced hypertension. Male adult Wistar rats (n=65) were randomly assigned to control, L-NAME, L-NAME+compound-21, L-NAME+olmesartan, and L-NAME+olmesartan+compound-21 groups and treated for 6 weeks. We observed that L-NAME hypertension was accompanied by enhanced PWV, increased wall thickness, and stiffness of the aorta, along with elevated hydroxyproline concentration. Olmesartan completely prevented hypertension, PWV and wall thickness increase, and the increase of aortic stiffness and partly prevented hydroxyproline accumulation. Compound 21 partly prevented all of these alterations, yet without concomitant prevention of blood pressure rise. Although the combination therapy with olmesartan and compound 21 led to blood pressure levels, PWV, and wall thickness comparable to olmesartan-alone-treated rats, only in the combination group was complete prevention of increased hydroxyproline deposition achieved, resulting in even more pronounced stiffness reduction. We conclude that chronic angiotensin II type 2 receptor stimulation prevented aortic stiffening and collagen accumulation without preventing hypertension in rats with inhibited NO synthase. These effects were additive to angiotensin II type 1 receptor blockade, yet without additional

  2. Nickel(II), copper(II) and zinc(II) metallo-intercalators: structural details of the DNA-binding by a combined experimental and computational investigation.

    PubMed

    Lauria, Antonino; Bonsignore, Riccardo; Terenzi, Alessio; Spinello, Angelo; Giannici, Francesco; Longo, Alessandro; Almerico, Anna Maria; Barone, Giampaolo

    2014-04-28

    We present a thorough characterization of the interaction of novel nickel(II) (1), copper(II) (2) and zinc(II) (3) Schiff base complexes with native calf thymus DNA (ct-DNA), in buffered aqueous solution at pH 7.5. UV-vis absorption, circular dichroism (CD) and viscometry titrations provided clear evidence of the intercalative mechanism of the three square-planar metal complexes, allowing us to determine the intrinsic DNA-binding constants (K(b)), equal to 1.3 × 10(7), 2.9 × 10(6), and 6.2 × 10(5) M(-1) for 1, 2 and 3, respectively. Preferential affinity, of one order of magnitude, toward AT compared to GC base pair sequences was detected by UV-vis absorption titrations of 1 with [poly(dG-dC)]2 and [poly(dA-dT)]2. Structural details of the intercalation site of the three metal complexes within [dodeca(dA-dT)]2 were obtained by molecular dynamics (MD) simulations followed by density functional theory/molecular mechanics (DFT/MM) calculations. The calculations revealed that three major intermolecular interactions contribute to the strong affinity between DNA and the three metal complexes: (1) the electrostatic attraction between the two positively charged triethylammoniummethyl groups of the metal complexes and the negatively charged phosphate groups of the DNA backbone; (2) the intercalation of the naphthalene moiety within the four nitrogen bases of the intercalation site; (3) the metal coordination by exocyclic donor atoms of the bases, specifically the carbonyl oxygen and amine nitrogen atoms. Remarkably, the Gibbs formation free energy calculated for the intercalation complexes of 1, 2 and 3 with [dodeca(dA-dT)]2 in the implicit water solution is in agreement with the experimental Gibbs free energy values obtained from the DNA-binding constants as ΔG° = -RT ln(K(b)). In particular, the DNA-binding affinity trend, 1 > 2 > 3, is reproduced. Finally, the first shell coordination distances calculated for the intercalation complex 3/[dodeca(dA-dT)]2 are in

  3. 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.

  4. Formation of As(II)-pyrite during experimental replacement of magnetite under hydrothermal conditions

    NASA Astrophysics Data System (ADS)

    Qian, Gujie; Brugger, Joël; Testemale, Denis; Skinner, William; Pring, Allan

    2013-01-01

    A 'new' type of arsenian pyrite was formed during experimental replacement of magnetite under hydrothermal conditions (T = 125 and 220 °C; Psat) and in the presence of S(-II) and various As-containing species. The amount of As in pyrite depended on the As-source, with sources containing cationic As (As(II), As(III) and As(V)) resulting in considerably higher amounts of As in the product arsenian pyrite than anionic sources. The highest As content was 23.83 ± 0.20 wt%, corresponding to a S:Fe:As molar ratio of 2:0.58:0.42. Electron probe micro-analyses revealed an inverse correlation between the Fe and As contents in the arsenian pyrite, indicating that As is substituting for Fe. Arsenic concentrations were highly inhomogeneous within the pyrite rim; in general, higher As contents were found within solid pyrite growing on the outer rim, compared to the highly porous and texturally complex pyrite found close to the reaction boundary. This likely reflects different uptake mechanisms for As during the pyrite nucleation and growth stages. X-ray Absorption Near Edge Structure (XANES) analyses showed that the As in the arsenian pyrite was predominantly in the form of As(II). Cross-sectional X-ray photoelectron spectroscopy (XPS) analysis of the arsenian pyrite confirmed the presence of As(II), but also showed evidence for more oxidized species (As(III) and As(V) oxides), as well as small amounts of polymeric As-As bonding. This indicates a large difference between As in the bulk (XANES measurements) and at the pyrite surface (XPS). Ab initio XANES calculations are consistent with As replacing Fe in pyrite in the form of As(II). Our experimental study suggests that the formal oxidation state of As in this type of arsenian pyrite is close to +2, and that in addition to fluid composition and oxidation state, the reaction path leading to pyrite formation plays a significant role in controlling the chemistry of arsenian pyrite.

  5. Experimental Infection of Domestic Pigs with African Swine Fever Virus Lithuania 2014 Genotype II Field Isolate.

    PubMed

    Gallardo, C; Soler, A; Nieto, R; Cano, C; Pelayo, V; Sánchez, M A; Pridotkas, G; Fernandez-Pinero, J; Briones, V; Arias, M

    2017-02-01

    An experimental infection was conducted to evaluate horizontal transmission, clinical, virological and humoral response induced in domestic pigs infected with African swine fever (ASF) genotype II virus circulating in 2014 into the European Union (EU). Ten naive pigs were placed in contact with eight pigs experimentally inoculated with the Lithuanian LT14/1490 ASF virus (ASFV) responsible for the first ASF case detected in wild boar in Lithuania in January 2014. Clinical examination and rectal temperature were recorded each day. Blood sampling from every animal was carried out twice weekly. Blood samples were examined for presence of ASF virus-specific antibodies and for determining the ASFV viral load. From the obtained results, it was concluded that the Lithuanian ASFV induced an acute disease which resulted in 94, 5% mortality. The disease was easily detected by real-time PCR prior to the onset of clinical signs and 33% of the animals seroconverted. All findings were in accordance with observations previously made in domestic pigs and wild boar when infected with ASF genotype II viruses characterized by a high virulence. One in-contact pig remained asymptomatic and survived the infection. The role of such animals in virus transmission would need further investigation. © 2015 Blackwell Verlag GmbH.

  6. Synthesis, characterization and investigation of electrochemical and spectroelectrochemical properties of non-peripherally tetra-5-methyl-1,3,4-thiadiazole substituted copper(II) iron(II) and oxo-titanium (IV) phthalocyanines

    NASA Astrophysics Data System (ADS)

    Demirbaş, Ümit; Akyüz, Duygu; Akçay, Hakkı Türker; Barut, Burak; Koca, Atıf; Kantekin, Halit

    2017-09-01

    In this study novel substituted phthalonitrile (3) and non-peripherally tetra 5-Methyl-1,3,4-thiadiazole substituted copper(II) (4), iron(II) (5) and oxo-titanium (IV) (6) phthalocyanines were synthesized. These novel compounds were fully characterized by FT-IR, 1H NMR, UV-vis and MALDI-TOF mass spectroscopic techniques. Voltammetric and in situ spectroelectrochemical measurements were performed for metallo-phthalocyanines (4-6). TiIVOPc and FeIIPc showed metal-based and ligand-based electron transfer reactions while CuIIPc shows only ligand-based electron transfer reaction. Voltammetric measurements indicated that the complexes have reversible, diffusion controlled and one-electron redox reactions. The assignments of the redox processes and color of the electrogenerated species of the complexes were determined with in-situ spectroelectrochemical and electrocolorimetric measurements. These measurements showed that the complexes can be used as the electrochromic materials for various display technologies.

  7. Hg(ii) and Pd(ii) complexes with a new selenoether bridged biscarbene ligand: efficient mono- and bis-arylation of methyl acrylate with a pincer biscarbene Pd(ii) precatalyst.

    PubMed

    Rishu; Prashanth, Billa; Bawari, Deependra; Mandal, Ushnish; Verma, Aditya; Choudhury, Angshuman Roy; Singh, Sanjay

    2017-05-16

    Two equivalents of 1-benzyl-3-bromoethylbenzimidazolium bromide couple with Na2Se to produce the first selenoether bridged bis-benzimidazolium salt (LH2)Br2. The nitrate (LH2)(NO3)2 and tetrafluoroborate (LH2)(BF4)2 salts were also synthesized from (LH2)Br2. The reaction of Hg(OAc)2 with (LH2)Br2 gave the first pseudo pincer carbene mercury complex, [Hg(L-κ(2)C)][HgBr4] (C1). Different complexes of Pd(ii) with selenoether bridged carbene were obtained using (LH2)Br2 and (LH2)(NO3)2. Syntheses of these complexes were dependent on the counter anion and the temperature. Thus, the pincer type ionic complex [PdBr(L-κ(3)CSeC)]Br (C2) was isolated at 80 °C and the pseudo pincer type neutral complex cis-[PdBr2(L-κ(2)C)] (C3) was isolated at room temperature from (LH2)Br2 and Pd(OAc)2 in DMSO. The nitrate precursor (LH2)(NO3)2 on palladation with Pd(OAc)2 afforded [Pd(L-κ(4)CBzCSeC)]NO3 (C4) showing an unprecedented intramolecular metallation at the ortho position of the benzyl wingtip of the benzimidazole moiety. The ligand salts and metal complexes have been characterized using HRMS, heteronuclear NMR and IR spectroscopy. Single crystal X-ray structures of the ligand salts (LH2)Br2 and (LH2)(BF4)2 and complexes C1-C4 have also been elucidated. Complex C2 showed good activity for C-C coupling in the mono-Heck reaction of methyl acrylate and arylbromides. Interestingly, the less common bis-arylation was also observed with deactivated arylbromides as the result of double-Heck coupling.

  8. Polymeric Cd(II), trinuclear and mononuclear Ni(II) complexes of 5-methyl-4-phenyl-1,2,4-triazole-3-thione: Synthesis, structural characterization, thermal behaviour, fluorescence properties and antibacterial activity

    NASA Astrophysics Data System (ADS)

    Bharty, M. K.; Paswan, S.; Dani, R. K.; Singh, N. K.; Sharma, V. K.; Kharwar, R. N.; Butcher, R. J.

    2017-02-01

    Syntheses of a polymeric Cd(II) complex, [Cd(mptt)2]n (1), a trinuclear Ni(II) complex, [Ni3(μ-mptt)4(μ-H2O)2(H2O)2(ttfa)2]·3H2O (2) and a mononuclear Ni(II) complex [Ni(mptt)2(en)2] (3) have been performed using the ligand 5-methyl-4-phenyl-1,2,4-triazole-3-thione (Hmptt) and nickel(II)/cadmium(II) salts {ttfa = thenoyltrifluroacetonate). The ligand and the complexes have been characterized by various physicochemical methods in addition to their single crystal X-ray structure. The Cd centre in complex 1 adopts a distorted tetrahedral geometry with one sulfur atom and two mptt ligands provide three nitrogen atoms from three triazole units. The sulfur atom of the ligand binds covalently and overall the ligand acts as uninigative N,S/N,N bidentate moiety. The polymeric structure of complex 1 results from the N atoms of the neighboring triazole units coordinating with the Cd(II) centre. The three Ni(II) centres in the trinuclear Ni(II) complex 2 form a linear arrangement and all have six coordinated arrangements. The middle Ni(II) binds with four deprotonated triazole ring nitrogens and two water molecules form two bridges. The terminal Ni(II) centres bind through two thenoyl oxygens, two triazole nitrogens and water molecules that formed bridges with the middle Ni centre. In complex 3, the nickel(II) centre is covalently bonded through two deprotonated triazole ring nitrogens from two ligand moieties and other four sites are occupied by four nitrogens from two bidentate en ligands. Thermogravimetric analyses (TGA) of the complexes indicated for NiO as the final residue. The bioefficacy of the ligand and complexes 2 and 3 have been examined against the growth of bacteria to evaluate their anti-microbial potential. Complex 2 showed high antibacterial activity as compared to the ligand and complex 3. Complexes 1, 2 and 3 are fluorescent materials with maximum emissions at 425, 421 and 396 nm at an excitation wavelength of 323, 348 and 322 nm, respectively.

  9. Differential effects of Mg(ii) and N(alpha)-4-tosyl-l-arginine methyl ester hydrochloride on the recognition and catalysis in ATP hydrolysis.

    PubMed

    Ma, Yanqing; Lu, Gongxuan

    2008-02-28

    The supramolecular interactions of Mg(ii) and N(alpha)-4-tosyl-l-arginine methyl ester hydrochloride (TAME) with ATP have been investigated using (1)H and (31)P NMR spectra. Furthermore, the hydrolysis of ATP catalyzed by Mg(ii) and TAME has been studied at 60 degrees C and pH 7 using (31)P NMR spectra. In the Mg(ii)-ATP-TAME ternary system, the binding interaction of Mg(2+) with ATP involves not only N1 and N7 in the adenine ring but also beta- and gamma-phosphate of ATP. The binding forces are mainly electrostatic interaction and cation (Mg(2+))-pi interaction. The guanidinium group and the aromatic ring of TAME interacts with ATP by beta and gamma phosphate and the adenine ring of ATP. The binding forces are mainly electrostatic interactions and pi-pi stacking. A significant difference between the binary and the ternary system indicates that TAME is essential to the stablization of the intermediate. Kinetic studies show that the hydrolysis rate constant of ATP is 2.16 x 10(-2) h(-1) at pH 7 in the Mg(ii)-TAME-ATP ternary system. The Mg(ii) ion and TAME can accelerate the ATP hydrolysis process. A possible mechanism has been proposed that the hydrolysis occurs through an addition-elimination, in which the phosphoramidate intermediate was observed at 3.21 ppm in the (31)P NMR of the ternary system. These results provide further information concerning the effect of the key amino acid residue and metal ions as cofactors of ATPase on ATP synthesis/hydrolysis at the molecular level.

  10. Di-μ2-chlorido-bis­[chlorido(η6-hexa­methyl­benzene)ruthenium(II)

    PubMed Central

    González-Torres, Yunuem; Espinosa-Jalapa, Noel; Hernández-Ortega, Simón; Le Lagadec, Ronan; Morales-Morales, David

    2009-01-01

    Dimeric mol­ecules of the title compound, [Ru2Cl4(C12H18)2], are located on a crystallographic centre of inversion with one mol­ecule in the asymmetric unit. The hexa­methyl­benzene rings are in an η6-coordination to the ruthenium centres, which are bridged by two chloride ligands. In addition, the ruthenium centres are bonded to another chloride ligand. The aromatic rings and the Ru2Cl2 four-membered ring enclose a dihedral angle of 55.85 (6)°. PMID:21578121

  11. Energy transfer in a ladder-type methyl-poly( para-phenylene) doped by Pt(II)octaethylporphyrin

    NASA Astrophysics Data System (ADS)

    Bagnich, S. A.; Im, C.; Bässler, H.; Neher, D.; Scherf, U.

    2004-03-01

    The luminescence of a ladder-type methyl-poly( para-phenylene) (MeLPPP) doped by platinum-porphyrin dye PtOEP covering the concentration 10 -3 to 5% by weight has been measured employing cw and transient techniques. Upon excitating into the range of absorption of the host strong phosphorescence of the dopant is observed. Possible ways of populating of the dopant triplet state are considered. It is shown that the main channel is singlet-singlet energy transfer among chromophor groups of the polymer followed by Förster-type transfer to the guest and subsequent intersystem crossing.

  12. 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.

  13. 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.

  14. (3-Methyl-benzo-nitrile-κN)tetra-kis(μ-N-phenyl-acetamidato)-κ(4) N:O;κ(4) O:N-di-rhodium(II)(Rh-Rh).

    PubMed

    Eagle, Cassandra T; Atem-Tambe, Nkongho; Kpogo, Kenneth K; Tan, Jennie; Quarshie, Fredricka

    2013-11-06

    In the title compound, [Rh2(C8H8NO)4(C8H7N)], the four acetamidate ligands bridging the dirhodium core are arranged in a 2,2-trans manner. One Rh(II) atom is five-coordinate, in a distorted pyramidal geometry, while the other is six-coord-in-ate, with a disorted octa-hedral geometry. For the six-coord-inate Rh(II) atom, the axial nitrile ligand shows a non-linear Rh-nitrile coordination with an Rh-N-C bond angle of 166.4 (4)° and a nitrile N-C bond length of 1.138 (6) Å. Each unique Rh(II) atom is coordinated by a trans pair of N atoms and a trans pair of O atoms from the four acetamide ligands. The Neq-Rh-Rh-Oeq torsion angles on the acetamide bridge varies between 12.55 (11) and 14.04 (8)°. In the crystal, the 3-methyl-benzo-nitrile ring shows a π-π inter-action with an inversion-related equivalent [inter-planar spacing = 3.360 (6) Å]. A phenyl ring on one of the acetamide ligands also has a face-to-face π-π inter-action with an inversion-related equivalent [inter-planar spacing = 3.416 (5) Å].

  15. Methyl 6-Amino-6-deoxy-d-pyranoside-Conjugated Platinum(II) Complexes for Glucose Transporter (GLUT)-Mediated Tumor Targeting: Synthesis, Cytotoxicity, and Cellular Uptake Mechanism.

    PubMed

    Li, Taoli; Gao, Xiangqian; Yang, Liu; Shi, Yunli; Gao, Qingzhi

    2016-05-19

    Methyl 6-aminodeoxy-d-pyranoside-derived platinum(II) glycoconjugates were designed and synthesized based on the clinical drug oxaliplatin for glucose transporter (GLUT)-mediated tumor targeting. In addition to a substantial improvement in water solubility, the conjugates exhibited cytotoxicity similar to or higher than that of oxaliplatin in six different human cancer cell lines. GLUT-mediated transport of the complexes was investigated with a cell-based fluorescence competition assay and GLUT-inhibitor-mediated cytotoxicity analysis in a GLUT-overexpressing human colorectal adenocarcinoma (HT29) cell line. The antitumor effect of the aminodeoxypyranoside-conjugated platinum(II) complexes was found to depend significantly on the GLUT inhibitor, and the cellular uptake of the molecules was regulated by GLUT-mediated transport. The results from this study demonstrate the potential advantages of aminodeoxypyranosides as sugar motifs for glycoconjugation for Warburg-effect-targeted drug design. These fundamental results also support the potential of aminodeoxypyranoside-conjugated platinum(II) complexes as lead compounds for further preclinical evaluation.

  16. New core@shell nanogel based 2-acrylamido-2-methyl-1-propane sulfonic acid for preconcentration of Pb(II) from various water samples

    NASA Astrophysics Data System (ADS)

    Shoueir, Kamel Rizq; Akl, Magda Ali; Sarhan, Ali Ali; Atta, Ayman Mohamdy

    2016-12-01

    Poly(vinyl alcohol) core coated with poly(2-acrylamido-2-methyl-1-propanesulfonic acid-co-N-isopropylacrylamide) shell to produce well-define PVA@P(AMPS-co-NIPAm) core shell nanogels with a core of 25 ± 0.5 nm and shell of 5 ± 0.5 nm. The synthetic approach was produced by a surfactant free emulsion polymerization (SFEP). The specific area was found to be 1685.8 m2/g. The nanogels were studied in a batch adsorption for removal of Pb(II) ions and characterized by SEM, TEM, TGA and BET measurements. The results showed that the adsorption equilibrium data fitted the Langmuir isotherm and the kinetic studies are well described by the pseudo-second-order kinetic model. The Pb(II) maximum adsorption was 510.2 (mg/g) for PVA@P(90AMPS-co-10NIPAm) (wt.: wt%). The PVA@P(AMPS-co-NIPAm) nanogels were applied for extracting of Pb(II) in real different environmental water samples successfully with high recoveries reaches 104.4%.

  17. Di-mu-hydroxido-bis{[bis(6-methyl-2-pyridylmethyl)(2-phenylethyl)amine-kappa(3)N',N'',N''']copper(II)} bis(perchlorate).

    PubMed

    García, Ana María; Manzur, Jorge; Vega, Andrés

    2007-07-01

    The title compund, [Cu(2)(OH)(2)(C(22)H(25)N(3))(2)](ClO(4))(2), is a copper(II) dimer, with two [CuL](2+) units [L is bis(6-methyl-2-pyridylmethyl)(2-phenylethyl)amine] bridged by hydroxide groups to define the {[CuL](mu-OH)(2)[CuL]}(2+) cation. Charge balance is provided by perchlorate counter-anions. The cation has a crystallographic inversion centre halfway between the Cu(II) ions, which are separated by 3.0161 (8) Angstrom. The central core of the cation is an almost regular Cu(2)O(2) parallelogram of sides 1.931 (2) and 1.935 (2) Angstrom, with a Cu-O-Cu angle of 102.55 (11) degrees . The coordination geometry around each Cu(II) centre can be best described as a square-based pyramid, with three N atoms from L ligands and two hydroxide O atoms completing the coordination environment. Each cationic unit is hydrogen bonded to two perchlorate anions by means of hydroxide-perchlorate O-H...O interactions.

  18. Polarized Light Scanning Cryomacroscopy, Part II: Thermal Modeling and Analysis of Experimental Observations

    PubMed Central

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

    2016-01-01

    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

  19. Hydrodynamic Radii of Intrinsically Disordered Proteins Determined from Experimental Polyproline II Propensities.

    PubMed

    Tomasso, Maria E; Tarver, Micheal J; Devarajan, Deepa; Whitten, Steven T

    2016-01-01

    The properties of disordered proteins are thought to depend on intrinsic conformational propensities for polyproline II (PPII) structure. While intrinsic PPII propensities have been measured for the common biological amino acids in short peptides, the ability of these experimentally determined propensities to quantitatively reproduce structural behavior in intrinsically disordered proteins (IDPs) has not been established. Presented here are results from molecular simulations of disordered proteins showing that the hydrodynamic radius (Rh) can be predicted from experimental PPII propensities with good agreement, even when charge-based considerations are omitted. The simulations demonstrate that Rh and chain propensity for PPII structure are linked via a simple power-law scaling relationship, which was tested using the experimental Rh of 22 IDPs covering a wide range of peptide lengths, net charge, and sequence composition. Charge effects on Rh were found to be generally weak when compared to PPII effects on Rh. Results from this study indicate that the hydrodynamic dimensions of IDPs are evidence of considerable sequence-dependent backbone propensities for PPII structure that qualitatively, if not quantitatively, match conformational propensities measured in peptides.

  20. 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. Copyright © 2016. Published by Elsevier Inc.

  1. Synthesis, characterization, and theoretical studies of Co(II) and Cu(II) complexes of 1-[(5-mercapto-[1,3,4]thiadiazol-2-ylimino)-methyl]-naphthalen-2-ol and its interaction with Cu nanoparticles

    NASA Astrophysics Data System (ADS)

    El-Wakiel, Nadia; El-Sayed, Yusif; Gaber, Mohamed

    2011-08-01

    The electronic absorption spectra of Schiff base namely 1-[(5-mercapto-[1,3,4]thiadiazol-2-ylimino)-methyl]-naphthalen-2-ol (H 2L) was studied in organic solvents of different polarity as well as in universal buffer solutions of varying pH values at room temperature; the pK a values were calculated. The effect of Co(II) and Cu(II) ions on the electronic absorption spectra of H 2L was also assigned and the stability constants of the complexes were calculated. The stoichiometry of the metal complexes was determined spectrophotometrically. Solid Co(II) and Cu(II) complexes with H 2L have been synthesized and characterized on the basis of elemental analyses, molar conductance, magnetic susceptibility measurements, IR, electronic as well as ESR spectral studies. The thermal decomposition of the metal complexes was studied by TGA and DTA techniques. The thermo-kinetic parameters; activation energy, pre-exponential factor and entropy of activation were estimated. The interaction between the Schiff base under investigation and the copper nanoparticles in the ground and excited state was considered. The fluorescence quenching rate constant of Schiff base by Cu nanoparticles has a large value.

  2. Crystal structure and photoluminescence properties of a new monomeric copper(II) complex: bis(3-{[(3-hydroxypropyl)imino]methyl}-4-nitrophenolato-κ(3)O,N,O')copper(II).

    PubMed

    Kocak, Cagdas; Oylumluoglu, Gorkem; Donmez, Adem; Coban, M Burak; Erkarslan, Ugur; Aygun, Muhittin; Kara, Hulya

    2017-05-01

    Copper(II)-Schiff base complexes have attracted extensive interest due to their structural, electronic, magnetic and luminescence properties. The title novel monomeric Cu(II) complex, [Cu(C10H11N2O4)2], has been synthesized by the reaction of 3-{[(3-hydroxypropyl)imino]methyl}-4-nitrophenol (H2L) and copper(II) acetate monohydrate in methanol, and was characterized by elemental analysis, UV and IR spectroscopies, single-crystal X-ray diffraction analysis and a photoluminescence study. The Cu(II) atom is located on a centre of inversion and is coordinated by two imine N atoms, two phenoxy O atoms in a mutual trans disposition and two hydroxy O atoms in axial positions, forming an elongated octahedral geometry. In the crystal, intermolecular O-H...O hydrogen bonds link the molecules to form a one-dimensional chain structure and π-π contacts also connect the molecules to form a three-dimensional structure. The solid-state photoluminescence properties of the complex and free H2L have been investigated at room temperature in the visible region. When the complex and H2L are excited under UV light at 349 nm, the complex displays a strong green emission at 520 nm and H2L displays a blue emission at 480 nm.

  3. Effects on peritoneal proteolysis and hemodynamics by high doses of methyl-prednisolone in experimental acute pancreatitis.

    PubMed

    Ruud, T E; Aasen, A O; Røise, O; Lium, B; Pillgram-Larsen, J; Stadaas, J O

    1986-01-01

    Acute pancreatitis was induced in 15 anesthetized pigs by injection of Na-taurocholate into the pancreatic duct. Seven animals were pretreated with methyl-prednisolone sodium succinate 30 mg/kg intravenously. Using chromogenic peptide substrate assays, values of trypsin (TRY), plasma prekallikrein (PKK), plasma kallikrein (KK) and functional plasma kallikrein inhibition capacity (KKI) were studied in the peritoneal exudate. Cardiac output (CO) and arterial pressure (AP) were regularly monitored before and during a six hour observation period. In acute untreated pancreatitis a 40% reduction of PKK levels was found paralleled by an increased KK activity and a reduction of KKI capacity. High TRY levels were found in several animals. The mortality rate was 63%. The pretreated animals all survived. CO and AP were significantly less reduced than in the untreated animals. Components of the plasma kallikrein-kinin system and TRY in the exudate remained mainly unchanged. Methyl-prednisolone given as pretreatment significantly improves hemodynamic parameters and increases the survival rate. Methyl-prednisolone suppresses generation of trypsin activity and activation of the plasma kallikrein-kinin system in the peritoneal exudate which may be of significant importance to the outcome.

  4. Methylation of HpaII and HhaI sites near the polymorphic CAG repeat in the human androgen-receptor gene correlates with X chromosome inactivation.

    PubMed Central

    Allen, R C; Zoghbi, H Y; Moseley, A B; Rosenblatt, H M; Belmont, J W

    1992-01-01

    The human androgen-receptor gene (HUMARA; GenBank) contains a highly polymorphic trinucleotide repeat in the first exon. We have found that the methylation of HpaII and HhaI sites less than 100 bp away from this polymorphic short tandem repeat (STR) correlates with X inactivation. The close proximity of the restriction-enzyme sites to the STR allows the development of a PCR assay that distinguishes between the maternal and paternal alleles and identifies their methylation status. The accuracy of this assay was tested on (a) DNA from hamster/human hybrid cell lines containing either an active or inactive human X chromosome; (b) DNA from normal males and females; and (c) DNA from females showing nonrandom patterns of X inactivation. Data obtained using this assay correlated substantially with those obtained using the PGK, HPRT, and M27 beta probes, which detect X inactivation patterns by Southern blot analysis. In order to demonstrate one application of this assay, we examined X inactivation patterns in the B lymphocytes of potential and obligate carriers of X-linked agammaglobulinemia. Images Figure 2 Figure 3 Figure 4 Figure 5 PMID:1281384

  5. Crystal structure of bis­{μ-2-[(di­methyl­amino)­meth­yl]ferrocene­seleno­lato}bis[chlorido­palladium(II)

    PubMed Central

    Takaluoma, Esther M.; Oilunkaniemi, Raija; Laitinen, Risto S.

    2014-01-01

    The dinuclear title compound, [PdCl{Se[(C5H5)Fe(C5H3)2CH2N(CH3)2]}]2 was obtained by the reaction of [PdCl2(NCPh)2] with 2-[(N,N′-di­methyl­amino)­meth­yl]ferro­cene­seleno­late and the crystals for the structure determination were grown from a mixture of THF and n-hexane. Both PdII atoms are coordinated by the bridging Se atoms and by the amino N atoms of the bidentate 2-[(N,N′-di­methyl­amino)­meth­yl]ferrocene­seleno­late ligand, as well as by Cl atoms, and show a distorted square-planar coordination. The angle between the Pd—Se—Se planes of the two Pd atoms is 149.31 (3)°. Weak Cl⋯H hydrogen bonds link the binuclear complexes into a three-dimensional network. PMID:25484672

  6. 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.

  7. 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.

  8. 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

  9. Bis[2-amino-6-methyl­pyrimidin-4(1H)-one-κ2 N 3,O]dichloridocadmium(II)

    PubMed Central

    Kaabi, Kamel; El Glaoui, Meher; Pereira Silva, P. S; Ramos Silva, M.; Ben Nasr, Cherif

    2010-01-01

    In the title compound, [CdCl2(C5H7N3O)2], the CdII atom is six-coordinated by two heterocyclic N atoms [Cd—N = 2.261 (2) and 2.286 (2) Å] and two O atoms [Cd—O = 2.624 (2) and 2.692 (2) Å] from two bidentate chelate 2-amino-6-methyl­pyrimidin-4(1H)-one ligands and two chloride ions [Cd—Cl = 2.4674 (6) and 2.4893 (7) Å]. The crystal packing is characterized by an open-framework architecture with the crystal packing stabilized by inter­molecular N—H⋯Cl and N—H⋯O hydrogen bonds. PMID:21587381

  10. Bis(4-acetyl-3-methyl-1-phenyl-1H-pyrazol-5-olato-κO,O')bis-(N,N-dimethyl-formamide-κO)nickel(II).

    PubMed

    Zhu, Hualing; Wei, Zhen; Bu, Luxia; Xu, Xiaoping; Shi, Jun

    2010-07-10

    The title complex, [Ni(C(12)H(11)N(2)O(2))(2)(C(3)H(7)NO)(2)], lies on on an inversion center. The Ni(II) ion is coordinated in a slightly distorted octa-hedral coordination enviroment by four O atoms from two bis-chelating 4-acety-3-methyl-1-phenyl-1H-pyrazol-5-olate ligands in the equatorial plane and two O atoms from two N,N-dimethyl-formamide ligands in the axial sites. In the crystal structure, weak inter-molecular π-π stacking inter-actions with centroid-centroid distances of 3.7467 (13) Å link mol-ecules into chains extending alongthe b axis.

  11. Diaqua­bis­(1-methyl-1H-imidazole-κN 3)bis­[2-(naphthalen-1-yl)acetato-κO]cobalt(II)

    PubMed Central

    Zhao, Hong; Yin, Fu-Jun; Xu, Xing-You; Han, Li-Jun

    2012-01-01

    In the title compound, [Co(C12H9O2)2(C4H6N2)2(H2O)2], the CoII ion is located on an inversion centre and displays a distorted octa­hedral coordination geometry. Two O atoms from two water mol­ecules and two carboxyl­ate O atoms from two 2-(naphthalen-1-yl)acetate ligands are in the equatorial plane and two N atoms from two 1-methyl-1H-imidazole ligands are in the axial positions. The structure is stabilized by intra­molecular O—H⋯O hydrogen bonds. Inter­molecular O—H⋯O hydrogen bonds link the complex mol­ecules into chains along [100]. PMID:22590060

  12. Bis[(1H-1,2,3-benzotriazol-1-yl)methyl 2,2-dimethyl-propano-ato-κN(3)]dichlorido-copper(II).

    PubMed

    Cao, Gang; Guo, Ting; Xu, Sen

    2012-05-01

    In the title compound, [CuCl(2)(C(12)H(15)N(3)O(2))(2)], the Cu(II) ion is located on an inversion center and is four-coordinated in a distorted square-planar geometry by two chloride anions and two N atoms from two (1H-1,2,3-benzotriazol-1-yl)methyl 2,2-dimethyl-propano-ate ligands. The Cl-Cu-N angles of 90.55 (9) and 89.45 (9)° are close to ideal values. In the crystal, weak π-π stacking inter-actions are observed between inversion-related benzene rings [centroid-centroid distance = 4.0028 (6) Å].

  13. (η6-Benzophenone)(η5-penta­methyl­cyclo­penta­dien­yl)ruthenium(II) tetra­phenyl­borate

    PubMed Central

    Loughrey, Bradley T.; Nadin, Kevin; Williams, Michael L.; Healy, Peter C.

    2009-01-01

    The structure of the title compound, [Ru(C10H15)(C13H10O)](C24H20B), consists of discrete [Cp*Ru(II)benzophenone] cations and tetra­phenyl­borate anions (Cp* = penta­methyl­cyclo­penta­dien­yl). Tethering the Cp*Ru group to one aryl ring of benzophenone results in average values of 1.42 (1) and 1.38 (1) Å for the C—C bond lengths in the Ru-tethered and untethered phenyl rings, respectively. The dihedral angle between the benzene and phenyl rings of the benzophenone group is 50.5 (1)°. PMID:21578208

  14. An experimental type II mixed cryoglobulinemia with renal glomerulopathy in ICR mice triggered by Capillaria hepatica infection.

    PubMed

    Aihara, Naoyuki; Chambers, James Kenn; Hosono, Kei; Kamiie, Junichi; Shirota, Kinji

    2011-12-01

    Type II mixed cryoglobulinemia is characterized by systemic vasculitis with deposition of cryoprecipitatable-immunoglobulins containing rheumatoid factor. Pathogenesis of type II mixed cryoglobulinemia has not yet been completely clarified because of the lack of an experimental animal. Here, we report an animal model of type II mixed cryoglobulinemia that is induced by experimental infection with Capillaria hepatica in ICR mice. Capillaria hepatica is a nematode that causes necrotic hepatitis in several mammals. In this study, mice experimentally infected with C. hepatica eggs developed cryoglobulinemia at 20 and 30 days post injection. Using immunological analysis, cryoglobulinemia in infected mice was classified as type II mixed cryoglobulinemia by detection of monoclonal IgM rheumatoid factor and IgA in the cryoprecipitate of serum. Using immunofluorescence, we observed an increase in the number of double-positive cells for µ heavy and κ light chains of immunoglobulin in the spleens of infected mice. Histopathologically, this model was characterized by glomerulopathy associated with intense deposition of IgM and IgA filling in capillary lumina. Ultrastructural analysis showed that glomerular deposits consisted of stacks of twisted microtubular structures. These serological and histological features resembled those of type II mixed cryoglobulinemia in human. This is the first experimental animal model of type II mixed cryoglobulinemia that will enable detailed studies on the pathogenesis of cryoglobulinemia.

  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. 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.

  17. 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

  18. Experimental evidence for type-II Dirac semimetal in PtSe2

    NASA Astrophysics Data System (ADS)

    Zhang, Kenan; Yan, Mingzhe; Zhang, Haoxiong; Huang, Huaqing; Arita, Masashi; Sun, Zhe; Duan, Wenhui; Wu, Yang; Zhou, Shuyun

    2017-09-01

    While a monolayer PtSe2 film is a semiconductor with interesting spin structure, bulk PtSe2 crystal has been predicted to be a topological Dirac semimetal that can host a new type of Lorentz-violating Dirac fermions. Despite the intriguing predictions, experimental progress on the electronic structure of bulk PtSe2 has been hindered due to the lack of large, high-quality single-crystal samples. Here we report the growth and characterization of high-quality PtSe2 single crystals and reveal the electronic structure to provide direct evidence for the existence of three-dimensional type-II Dirac fermions. A comparison of the crystal, vibrational, and electronic structure to a related compound, PtTe2, is also discussed. Our work provides an important platform for exploring the novel quantum phenomena associated with type-II Dirac fermions in the 1 T -PtSe2 class of transition-metal dichalcogenides.

  19. Trans-amniotic stem cell therapy (TRASCET) minimizes Chiari-II malformation in experimental spina bifida.

    PubMed

    Dionigi, Beatrice; Brazzo, Joseph A; Ahmed, Azra; Feng, Christina; Wu, Yaotang; Zurakowski, David; Fauza, Dario O

    2015-06-01

    We sought to study the impact of trans-amniotic stem cell therapy (TRASCET) in the Chiari-II malformation in experimental spina bifida. Sprague-Dawley fetuses (n=62) exposed to retinoic acid were divided into three groups at term (21-22 days gestation): untreated isolated spina bifida (n=21), isolated spina bifida treated with intra-amniotic injection of concentrated, syngeneic, labeled amniotic fluid mesenchymal stem cells (afMSCs) on gestational day 17 (n=28), and normal controls (n=13). Analyses included measurements of brainstem and cerebellar placement on high resolution MRI and histology. Statistical comparisons included ANOVA. In parallel to the expected induced coverage of the spina bifida in the afMSC-treated group (P<0.001), there were statistically significant differences in brainstem displacement across the groups (P<0.001), with the highest caudal displacement in the untreated group. Significant differences in cerebellar displacement were also noted, albeit less pronounced. Pairwise comparisons were statistically significant, with P=0.014 between treated and normal controls in caudal brainstem displacement and P<0.001 for all other comparisons. Labeled afMSCs were identified in 71% of treated fetuses. Induced coverage of spina bifida by TRASCET minimizes the Chiari-II malformation in the retinoic acid rodent model, further suggesting it as a practical alternative for the prenatal management of spina bifida. Copyright © 2015 Elsevier Inc. All rights reserved.

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

    PubMed

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

    2015-02-18

    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.

  1. Mortality in experimental adjuvant intraoperative photodynamic therapy (AIOPDT) using ALA, Photofrin II, and mTHPC

    NASA Astrophysics Data System (ADS)

    Winkler, Steffi; Prosst, Ruediger L.; Stern, Josef; Rheinwald, Markus; Haase, Thomas; Herfarth, Christian; Gahlen, Johannes

    2001-01-01

    A clinical problem in the treatment of colorectal cancer is the high rate of local tumor recurrence. Adjuvant therapy methods are necessary to receive a better clinical outcome in minimizing local tumor relapse. Adjuvant intraoperative photodynamic therapy (AIOPDT) seems to be a promising alternative therapy in the treatment of malignant colorectal diseases. IN experimental settings the success of AIOPDT depends on the accumulation of the photosensitizer (PS) in tumor tissue and may be jeopardized by high mortality rates, due to inadequate energy doses. Our study evaluated mortality rates of nude mice after AIOPDT with ALA, Photofrin II and mTHPC using the following various light doses: ALA/Photofrin II: 100J, 50J, 25J; mTHPC: 30J, 15J, 5J generated by an Argon-Dye-laser system. There was a close correlation between laser energy applied for AIOPDT and postoperative mortality rate. Initial high mortality rates were lowered by stepwise reduction of the energy dose. Mortality rates reached a maximum 24 hours after AIOPDT in all groups.

  2. 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

  3. 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.

  4. Copper(II) bis [2-((E)-2-(pyrid-2-yl)ethylimino)methyl)-6-bromo-4-chlorophenolate

    SciTech Connect

    Zhang, X. L.

    2013-01-15

    A new complex CuL{sub 2} [HL = 2-((E)-(2-(pyridin-2-yl)ethylimino)methyl)-6-bromo-4-chlorophenol] was synthesized, and its structure (C{sub 28}H{sub 22}Br{sub 2}Cl{sub 2}CuN{sub 4}O{sub 2}, Mr = 740.76) was determined by single-crystal X-ray diffraction analysis. The crystal belongs to the triclinic system, space group P1{sup -}, with a = 5.157(6), b = 12.090(1), c =12.310(1) A, {alpha} = 113.962(2) Degree-Sign , {beta} = 96.7910(10) Degree-Sign , {gamma} = 90.0300(10) Degree-Sign , V = 695.4(8) A{sup 3}, Z = 1, R = 0.0481. The complex molecules are linked via the weak C-H...N hydrogen bonds, leading to the formation of one dimension (1D) chains along the a axis.

  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. 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.

  7. 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.

    PubMed

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

    2010-10-15

    Tetra((1-hydroxyiminomethylnaphthalen-2-yloxy)methyl)ethene (THIMNYOME), H(4)L, 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, (1)H- and (13)C 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 (CN) 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.

  8. Flotation of traces of silver and copper(II) ions with a methyl cellosolve solution of dithizone.

    PubMed

    Hiraide, M; Mizuike, A

    1975-06-01

    Microgram quantities of silver and copper(II) ions in aqueous solutions are collected on dithizone precipitates, which are then floated with the aid of small nitrogen bubbles. This separation technique has been successfully applied to the atomic-absorption spectrophotometric determination of down to a tenth ppm of silver and copper in high-purity lead and zinc metals.

  9. Mechanistic and biological characteristics of different sugar conjugated 2-methyl malonatoplatinum(II) complexes as new tumor targeting agents.

    PubMed

    Gao, Xiangqian; Liu, Shengnan; Shi, Yunli; Huang, Zhenhua; Mi, Yi; Mi, Qian; Yang, Jinna; Gao, Qingzhi

    2017-01-05

    Novel cis-2-methylmalonato(trans-R,R-cyclohexane-1,2-diamine)platinum(II) glycoconjugates derived from different sugar motifs, namely, glucose (Glu-Me-Pt), mannose (Man-Me-Pt) and galactose (Gal-Me-Pt) were designed and synthesized based on the third generation clinical drug oxaliplatin for potential glucose transporters (GLUTs) mediated tumor targeting. All platinum(II) glycoconjugates were characterized by (1)H NMR, (13)C NMR, IR, HRMS as well as (195)Pt-NMR analysis. Despite their substantial improvement in water solubility, the conjugates exhibited comparable or better in vitro cytotoxicities than oxaliplatin determined in six different human cancer cell lines. Glu-Me-Pt has been shown to be more effective than cisplatin and oxaliplatin with improved therapeutic index in leukemia-bearing DBA/2 mice model. The potential GLUT transportability of the complexes was investigated using cell-based fluorescent competition assay and GLUT inhibitor mediated cell viability analysis in GLUT over-expressing HT29 cell line. Each sugar motif was found to be useful to enable the platinum(II) complexes as substrate for GLUT mediated cell uptake. In vitro DNA adduct formation analysis has been investigated for the first time for this class of compounds to reveal the intrinsic differences in antitumor activity between the malonatoplatinum(II) glycoconjugates and oxaliplatin. The intrinsic DNA reactivity of the platinum(II)-sugar conjugates was found as Gal-Me-Pt > Glu-Me-Pt > Man-Me-Pt ≈ oxaliplatin by kinetic study on the formation of platinum(II) adducts with guanosine-5'-monophosphate (5'-GMP). The results from this study demonstrate the usefulness of glucose, mannose and galactose as alternative sugar motif on glycoconjugation for GLUT mediated drug design and pharmaceutical R&D, and the obtained fundamental results also support the potential of the GLUT targeted platinum(II)-sugar conjugates as lead compounds for further pre-clinical evaluation. Copyright

  10. 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.

  11. 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

  12. Experimental Demonstration of Frequency Regulation by Commercial Buildings – Part II: Results and Performance Evaluation

    DOE PAGES

    Vrettos, Evangelos; Kara, Emre Can; MacDonald, Jason; ...

    2016-11-15

    This paper is the second part of a two-part series presenting the results from an experimental demonstration of frequency regulation in a commercial building test facility. We developed relevant building models and designed a hierarchical controller for reserve scheduling, building climate control and frequency regulation in Part I. In Part II, we introduce the communication architecture and experiment settings, and present extensive experimental results under frequency regulation. More specifically, we compute the day-ahead reserve capacity of the test facility under different assumptions and conditions. Furthermore, we demonstrate the ability of model predictive control to satisfy comfort constraints under frequency regulation,more » and show that fan speed control can track the fast-moving RegD signal of the Pennsylvania, Jersey, and Maryland Power Market (PJM) very accurately. In addition, we discuss potential effects of frequency regulation on building operation (e.g., increase in energy consumption, oscillations in supply air temperature, and effect on chiller cycling), and provide suggestions for real-world implementation projects. Our results show that hierarchical control is appropriate for frequency regulation from commercial buildings.« less

  13. Experimental Demonstration of Frequency Regulation by Commercial Buildings – Part II: Results and Performance Evaluation

    SciTech Connect

    Vrettos, Evangelos; Kara, Emre Can; MacDonald, Jason; Andersson, Goran; Callaway, Duncan S.

    2016-11-15

    This paper is the second part of a two-part series presenting the results from an experimental demonstration of frequency regulation in a commercial building test facility. We developed relevant building models and designed a hierarchical controller for reserve scheduling, building climate control and frequency regulation in Part I. In Part II, we introduce the communication architecture and experiment settings, and present extensive experimental results under frequency regulation. More specifically, we compute the day-ahead reserve capacity of the test facility under different assumptions and conditions. Furthermore, we demonstrate the ability of model predictive control to satisfy comfort constraints under frequency regulation, and show that fan speed control can track the fast-moving RegD signal of the Pennsylvania, Jersey, and Maryland Power Market (PJM) very accurately. In addition, we discuss potential effects of frequency regulation on building operation (e.g., increase in energy consumption, oscillations in supply air temperature, and effect on chiller cycling), and provide suggestions for real-world implementation projects. Our results show that hierarchical control is appropriate for frequency regulation from commercial buildings.

  14. Centrifugal slurry pump wear and hydraulic studies. Phase II report. Experimental studies

    SciTech Connect

    Mistry, D.; Cooper, P.; Biswas, C.; Sloteman, D.; Onuschak, A.

    1983-01-01

    This report describes the work performed by Ingersoll-Rand Research, Inc., under Phase II, Experimental Studies for the contract entitled, Centrifugal Slurry Pump Wear and Hydraulic Studies. This work was carried out for the US Department of Energy under Contract No. DE-AC-82PC50035. The basic development approach pursued this phase is presented, followed by a discussion on wear relationships. The analysis, which resulted in the development of a mathematical wear model relating pump life to some of the key design and operating parameters, is presented. The results, observations, and conclusions of the experimental investigation on small scale pumps that led to the selected design features for the prototype pump are discussed. The material investigation was performed at IRRI, ORNL and Battelle. The rationale for selecting the materials for testing, the test methods and apparatus used, and the results obtained are presented followed by a discussion on materials for a prototype pump. In addition, the prototype pump test facility description, as well as the related design and equipment details, are presented. 20 references, 53 figures, 13 tables.

  15. 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...

  16. 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...

  17. 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.

  18. Mercury(II) complexes with 5-methyl-5-(4-pyridyl)-2,4-imidazolidenedione: Synthesis, structural characterization, and theoretical studies

    NASA Astrophysics Data System (ADS)

    Sabounchei, Seyyed Javad; Shahriary, Parisa; Salehzadeh, Sadegh; Gholiee, Yasin; Khavasi, Hamid Reza

    2013-11-01

    New Hg(II) complexes with 5-methyl-5-(4-pyridyl)-2,4-imidazolidenedione (L) and various halogen ions were synthesized. Based on elemental analysis and flame atomic absorption spectroscopy, complexes have general formula HgL2X2 (X = Cl- (1), Br- (2), and I- (3)). These compounds have been studied by IR, 1H and 13C NMR spectroscopy at room temperature. According to X-ray diffraction analysis, complex 2 crystallizes in monoclinic system. Hg(II) ion has been surrounded by a distorted tetrahedral arrangement of two monodentate ligands (each one coordinating by a Npyridine ring atom) and two bromine atoms. Based on crystal packing findings, intermolecular classical H-bonds of the type Nsbnd H⋯O and non-classical H-bonds of the type Csbnd H⋯O and Csbnd H⋯Br, as an important member of noncovalent interaction family, are driving forces for the formation of a very distorted structure. Theoretical studies showed that neither the size of the halide anion nor the intramolecular interactions between two ligands are the reason for the very small Nsbnd Hgsbnd N bond angle, observed in complex 2.

  19. Employment of methyl 2-pyridyl ketone oxime in manganese non-carboxylate chemistry: Mn(II)(2)Mn(IV) and Mn(II)(2)Mn(III)(6) complexes.

    PubMed

    Stoumpos, Constantinos C; Stamatatos, Theocharis C; Sartzi, Harikleia; Roubeau, Olivier; Tasiopoulos, Anastasios J; Nastopoulos, Vassilios; Teat, Simon J; Christou, George; Perlepes, Spyros P

    2009-02-14

    The employment of the anion of methyl 2-pyridyl ketone oxime (mpko(-)) as a tridentate chelating/bridging ligand in manganese chemistry is described. The inorganic anion (Br(-), ClO(4)(-)) used in the reaction affects the identity of the product. The reaction of MnBr(2) and one equivalent of mpkoH in the presence of a base affords [Mn(3)(OMe)(2)(mpko)(4)Br(2)] (3), which is mixed-valence (2Mn(II), Mn(IV)). The central Mn(IV) atom in each of the two, crystallographically independent, centrosymmetric molecules is coordinated by four oximate oxygen atoms belonging to the eta(1):eta(1):eta(1):mu mpko(-) ligands, and two eta(1):mu MeO(-) groups, while six coordination at each terminal Mn(II) atom is completed by four nitrogen atoms belonging to the 'chelating' part of two mpko(-) ligands, and one Br(-) ion. The Mn(II) atoms have trigonal prismatic coordination geometry. The reaction of Mn(ClO(4))(2).6H(2)O, mpkoH and OH(-) (1:2:1) in MeOH gives [Mn(8)O(4)(OMe)(mpko)(9)(mpkoH)](ClO(4))(4) (4), which is also mixed-valence (2Mn(II), 6Mn(III)) and possesses the novel [Mn(8)(mu(3)-O)(4)(mu-OMe)(mu-OR'')(2)](11+) core. The latter possesses a U-shaped sequence of four fused {Mn(II)Mn(III)(2)(mu(3)-O)}(6+) triangular units, with a Mn(III)-Mn(III) edge being shared between the central triangles. Variable-temperature, solid-state dc and ac magnetic susceptibility studies were carried out on complexes 3 and 4 . The dc susceptibility data for 3 in the 5.0-300 K range have been fit to a model with two J values, revealing weak ferromagnetic Mn(II)Mn(IV) (J = +3.4 cm(-1)) and Mn(II)Mn(II) (J' = +0.3 cm(-1)) exchange interactions. Fitting of the magnetization vs. H/T data by matrix diagonalization and including only axial anisotropy (ZFS, D) gave ground state spin (S) and D values of S = 13/2, D = +0.17 cm(-1) for and S = 3, D = -0.09 cm(-1) for 4 . The combined work demonstrates the usefulness of mpko(-) in the preparation of interesting Mn clusters, without requiring the co

  20. Dichloridobis[(ferrocenyl­methyl­idene)(furan-2-ylmeth­yl)amine-κN]palladium(II)

    PubMed Central

    Motswainyana, William M.; Onani, Martin O.; Lalancette, Roger A.

    2012-01-01

    The title compound, [Fe2Pd(C5H5)2(C11H10NO)2Cl2], exhibits a square-planar geometry at the PdII atom, which is determined by inversion-related chlorine and ferrocenyl­imine mol­ecules across a center of symmetry. The ferrocenyl­imine moieties are trans to each other. PMID:22589775

  1. Acceleration of intramolecular vibrational redistribution by methyl internal rotation. II. A comparison of m-fluorotoluene and p-fluorotoluene

    NASA Astrophysics Data System (ADS)

    Timbers, Peter J.; Parmenter, Charles S.; Moss, David B.

    1994-01-01

    Comparisons of rate constants for intramolecular vibrational redistribution (IVR) within the S1 manifolds of aromatic molecules with and without methyl internal rotation have been extended to meta-fluorotoluene (mFT). The IVR rate constant, as determined by the method of O2 fluorescence quenching (chemical timing), is 8.2×1011 s-1 for the zero-order level 31 with ɛvib≊1250 cm-1. This rate is approximately 10 times greater than that for the comparable level in para-fluorotoluene (pFT). The IVR rate in pFT in turn exceeds that for a comparable level in para-difluorobenzene (pDFB) by a factor of 40. We consider these differences using the Fermi golden rule formulation of the IVR rate constant. The enhanced value for mFT vs pFT may be a consequence of increased coupling strength between the internal rotation and molecular vibration plus a combination of factors that increase the coupled state density. This result is in contrast to the comparison between pFT and pDFB, where IVR acceleration is attributed primarily to the increased density of coupled states provided by introducing the internal rotation-vibration interaction.

  2. 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.

  3. 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.

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

    PubMed

    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.

  5. 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

  6. 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

  7. Civilian nuclear power on the drawing board: the development of Experimental Breeder Reactor-II.

    SciTech Connect

    Westfall, C.

    2003-02-20

    On September 28, 2001 a symposium was held at Argonne National Laboratory as part of the festivities to mark the 100th birthday of Enrico Fermi. The symposium celebrated Fermi's ''contribution to the development of nuclear power'' and focused on one particular ''line of development'' resulting from Fermi's interest in power reactors: Argonne's fast reactor program. Symposium participants made many references to the ways in which the program was linked to Fermi, who led the team which created the world's first self-sustaining nuclear chain reaction. For example, one presentation featured an April, 1944 memo that described a meeting attended by Fermi and others. The memo came from the time when research on plutonium and the nuclear chain reaction at Chicago's WWII Metallurgical Laboratory was nearing its end. Even as other parts of the Manhattan Engineering Project were building on this effort to create the bombs that would end the war, Fermi and his colleagues were taking the first steps to plan the use of nuclear energy in the postwar era. After noting that Fermi ''viewed the use of [nuclear] power for the heating of cities with sympathy,'' the group outlined several power reactor designs. In the course of discussion, Fermi and his colleagues took the first steps in conjuring the vision that would later be brought to life with Experimental Breeder Reactor I (EBR-I) and Experimental Breeder Reactor II (EBR-II), the celebrated achievements of the Argonne fast reactor program. Group members considered various schemes for a breeder reactor in which the relatively abundant U-238 would be placed near a core of fissionable material. The reactor would be a fast reactor; that is, neutrons would not be moderated, as were most wartime reactors. Thus, the large number of neutrons emitted in fast neutron fission would hit the U-238 and create ''extra'' fissionable material, that is, more than ''invested,'' and at the same time produce power. The group identified the problem of

  8. Mononuclear nickel (II) and copper (II) coordination complexes supported by bispicen ligand derivatives: Experimental and computational studies

    SciTech Connect

    Singh, Nirupama; Niklas, Jens; Poluektov, Oleg; Van Heuvelen, Katherine M.; Mukherjee, Anusree

    2017-01-01

    The synthesis, characterization and density functional theory calculations of mononuclear Ni and Cu complexes supported by the N,N’-Dimethyl-N,N’-bis-(pyridine-2-ylmethyl)-1,2-diaminoethane ligand and its derivatives are reported. The complexes were characterized by X-ray crystallography as well as by UV-visible absorption spectroscopy and EPR spectroscopy. The solid state structure of these coordination complexes revealed that the geometry of the complex depended on the identity of the metal center. Solution phase characterization data are in accord with the solid phase structure, indicating minimal structural changes in solution. Optical spectroscopy revealed that all of the complexes exhibit color owing to d-d transition bands in the visible region. Magnetic parameters obtained from EPR spectroscopy with other structural data suggest that the Ni(II) complexes are in pseudo-octahedral geometry and Cu(II) complexes are in a distorted square pyramidal geometry. In order to understand in detail how ligand sterics and electronics affect complex topology detailed computational studies were performed. The series of complexes reported in this article will add significant value in the field of coordination chemistry as Ni(II) and Cu(II) complexes supported by tetradentate pyridyl based ligands are rather scarce.

  9. 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-.

  10. Case Control Study of Type II Decompression Sickness Associated with Patent Foramen Ovale in Experimental No-Decompression Dives

    DTIC Science & Technology

    2010-05-01

    DECOMPRESSION SICKNESS ASSOCIATED WITH PATENT FORAMEN OVALE IN EXPERIMENTAL NO-DECOMPRESSION DIVES Authors: Navy Experimental Diving Unit G. W. Latson...08 NO. 11. TITLE (Include Security Classification) (U) Case Control Study of Type II Decompression Sickness Associated with Patent Foramen Ovale in...reverse if necessary 17. COSATI CODES and identify by block number) FIELD GROUP SUB-GROUP Decompression sickness, DCS, DCI, patent foramen ovale , PFO

  11. 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.

  12. trans-Dichloridobis{tris-[4-(trifluoro-methyl)phen-yl]phosphane-κP}palla-dium(II) dichloro-methane monosolvate.

    PubMed

    Davis, Wade L; Muller, Alfred

    2012-12-01

    The title compound, [PdCl2(C21H12F9P)2]·CH2Cl2, crystallizes with two independent complex molecules (each having the Pd(II) atom situated on an inversion centre) and a dichloro-methane molecule in the asymmetric unit. The independent Pd(II) atoms are in perfectly linear orientations of the ligands in mutually trans positions, but distortions of the Cl-Pd-P angles ranging from 86.151 (19) to 93.849 (19)° are evident. The effective cone angles for the tris-[4-(trifluoro-meth-yl)phen-yl]phosphane ligand were calculated to be 159 and 161°. In the crystal, weak C-H⋯Cl/F inter-actions create a three-dimensional supramolecular network. Loose packing at two of the -CF3 groups resulted in large thermal vibrations which were treated as two-component disorders [occupancy ratios 0.50:0.50 and 0.628 (15):0.372 (15)].

  13. A novel urotensin II receptor antagonist, KR-36996, improved cardiac function and attenuated cardiac hypertrophy in experimental heart failure.

    PubMed

    Oh, Kwang-Seok; Lee, Jeong Hyun; Yi, Kyu Yang; Lim, Chae Jo; Park, Byung Kil; Seo, Ho Won; Lee, Byung Ho

    2017-03-15

    Urotensin II and its receptor are thought to be involved in various cardiovascular diseases such as heart failure, pulmonary hypertension and atherosclerosis. Since the regulation of the urotensin II/urotensin II receptor offers a great potential for therapeutic strategies related to the treatment of cardiovascular diseases, the study of selective and potent antagonists for urotensin II receptor is more fascinating. This study was designed to determine the potential therapeutic effects of a newly developed novel urotensin II receptor antagonist, N-(1-(3-bromo-4-(piperidin-4-yloxy)benzyl)piperidin-4-yl)benzo[b]thiophene-3-carboxamide (KR-36996), in experimental models of heart failure. KR-36996 displayed a high binding affinity (Ki=4.44±0.67nM) and selectivity for urotensin II receptor. In cell-based study, KR-36996 significantly inhibited urotensin II-induced stress fiber formation and cellular hypertrophy in H9c2UT cells. In transverse aortic constriction-induced cardiac hypertrophy model in mice, the daily oral administration of KR-36996 (30mg/kg) for 14 days significantly decreased left ventricular weight by 40% (P<0.05). In myocardial infarction-induced chronic heart failure model in rats, repeated echocardiography and hemodynamic measurements demonstrated remarkable improvement of the cardiac performance by KR-36996 treatment (25 and 50mg/kg/day, p.o.) for 12 weeks. Moreover, KR-36996 decreased interstitial fibrosis and cardiomyocyte hypertrophy in the infarct border zone. These results suggest that potent and selective urotensin II receptor antagonist could efficiently attenuate both cardiac hypertrophy and dysfunction in experimental heart failure. KR-36996 may be useful as an effective urotensin II receptor antagonist for pharmaceutical or clinical applications.

  14. Personalized translational epilepsy research - Novel approaches and future perspectives: Part II: Experimental and translational approaches.

    PubMed

    Bauer, Sebastian; van Alphen, Natascha; Becker, Albert; Chiocchetti, Andreas; Deichmann, Ralf; Deller, Thomas; Freiman, Thomas; Freitag, Christine M; Gehrig, Johannes; Hermsen, Anke M; Jedlicka, Peter; Kell, Christian; Klein, Karl Martin; Knake, Susanne; Kullmann, Dimitri M; Liebner, Stefan; Norwood, Braxton A; Omigie, Diana; Plate, Karlheinz; Reif, Andreas; Reif, Philipp S; Reiss, Yvonne; Roeper, Jochen; Ronellenfitsch, Michael W; Schorge, Stephanie; Schratt, Gerhard; Schwarzacher, Stephan W; Steinbach, Joachim P; Strzelczyk, Adam; Triesch, Jochen; Wagner, Marlies; Walker, Matthew C; von Wegner, Frederic; Rosenow, Felix

    2017-09-13

    Despite the availability of more than 15 new "antiepileptic drugs", the proportion of patients with pharmacoresistant epilepsy has remained constant at about 20-30%. Furthermore, no disease-modifying treatments shown to prevent the development of epilepsy following an initial precipitating brain injury or to reverse established epilepsy have been identified to date. This is likely in part due to the polyetiologic nature of epilepsy, which in turn requires personalized medicine approaches. Recent advances in imaging, pathology, genetics, and epigenetics have led to new pathophysiological concepts and the identification of monogenic causes of epilepsy. In the context of these advances, the First International Symposium on Personalized Translational Epilepsy Research (1st ISymPTER) was held in Frankfurt on September 8, 2016, to discuss novel approaches and future perspectives for personalized translational research. These included new developments and ideas in a range of experimental and clinical areas such as deep phenotyping, quantitative brain imaging, EEG/MEG-based analysis of network dysfunction, tissue-based translational studies, innate immunity mechanisms, microRNA as treatment targets, functional characterization of genetic variants in human cell models and rodent organotypic slice cultures, personalized treatment approaches for monogenic epilepsies, blood-brain barrier dysfunction, therapeutic focal tissue modification, computational modeling for target and biomarker identification, and cost analysis in (monogenic) disease and its treatment. This report on the meeting proceedings is aimed at stimulating much needed investments of time and resources in personalized translational epilepsy research. This Part II includes the experimental and translational approaches and a discussion of the future perspectives, while the diagnostic methods, EEG network analysis, biomarkers, and personalized treatment approaches were addressed in Part I [1]. Copyright © 2017

  15. Bis[bis­(penta­methyl­cyclo­penta­dien­yl)cobalt(III)] tetra­chlorido­cobaltate(II) di­chloro­methane disolvate

    PubMed Central

    Merola, Joseph S.; Ngo, Mai; Karpin, George W.

    2013-01-01

    The title compound, [Co(C10H15)2]2[CoCl4]·2CH2Cl2, was isolated as a dichloromethane solvate and was formed in the reaction between lithium penta­methyl­cyclo­penta­dienide and anyhydrous cobalt(II) chloride in tetra­hydro­furan. There are two deca­methyl­cobaltocenium cations, one tetrachloridocobaltate(II) anion and two di­chloro­methane solvent mol­ecules in the formula unit. There is a slight disorder of the di­chloro­methane solvent which was treated with a two-site model [occupancy rates = 0.765 (4) and 0.235 (4)]. The di­chloro­methane mol­ecules display significant C—H⋯Cl inter­actions with the tetrachloridocobaltate(II) dianion. The cobalt atom of the deca­methyl­cobaltocenium cation sits on a twofold rotation axis, with only one penta­methyl­cyclo­penta­diene ligand being unique and the second generated by symmetry. The cobalt atom of the [CoCl4]−2 ion sits on a special site with -4 symmetry, with one unique chloride ligand and the others generated by the fourfold inversion axis. PMID:24426998

  16. 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.

  17. 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

  18. Blocking glutamate carboxypeptidase II inhibits glutamate excitotoxicity and regulates immune responses in experimental autoimmune encephalomyelitis.

    PubMed

    Ha, Danbee; Bing, So Jin; Ahn, Ginnae; Kim, Jinhee; Cho, Jinhee; Kim, Areum; Herath, Kalahe H I N M; Yu, Hak Sun; Jo, Sangmee Ahn; Cho, Ik-Hyun; Jee, Youngheun

    2016-09-01

    Experimental autoimmune encephalomyelitis (EAE) is an inflammatory disease in the murine central nervous system (CNS) and recapitulates the clinical and pathological features of human multiple sclerosis (MS). Glutamate carboxipeptidase II (GCPII), an enzyme expressed exclusively on astrocytes, is known to affect the disease progression of various neurological disorders by producing glutamate. Despite several findings indicating possible link between glutamate and MS/EAE, however, the involvement of astrocyte or GCPII on glutamate excitotoxicity has not received much attention in MS/EAE. When we examined GCPII expression during EAE progression in this study, we observed significantly elevated GCPII expression in peak stage of disease localized mainly in astrocytes. Intrigued by these results, we tried a potent GCPII inhibitor, 2-phosphonomethyl pentanedioic acid (2-PMPA), on EAE mice and noticed markedly attenuated EAE clinical signs along with significantly inhibited infiltration of inflammatory cells into CNS. Furthermore, 2-PMPA dampened the function of Th1 cell lineage and down-regulated mGluR1 expression in both periphery and CNS contributing to glutamate-mediated immune regulation. Our observations identify a sequence of events triggering EAE through GCPII overexpression, which may offer a novel therapeutic approach to the treatment of MS. © 2016 Federation of European Biochemical Societies.

  19. A novel embeddable spherical smart aggregate for structural health monitoring: part II. Numerical and experimental verifications

    NASA Astrophysics Data System (ADS)

    Kong, Qingzhao; Fan, Shuli; Mo, Y. L.; Song, Gangbing

    2017-09-01

    The newly developed spherical smart aggregate (SSA) based on a radially polarized spherical piezoceramic shell element has unique omnidirectional actuating and sensing capabilities that can greatly improve the detection aperture and provide additional functionalities in health monitoring applications in concrete structures. Detailed fabrication procedures and electrical characterization of the SSA have been previously studied (Part I). In this second paper (Part II), the functionalities of the SSA used in both active sensing and passive sensing approaches were investigated in experiments and numerical simulations. One SSA sample was embedded in a 1 ft3 concrete specimen. In the active sensing approach, the SSA was first utilized as an actuator to generate stress waves and six conventional smart aggregates (SA) mounted on the six faces of the concrete cube were utilized as sensors to detect the wave response. Conversely, the embedded SSA was then utilized as a sensor to successively detect the wave response from each SA. The experimentally obtained behavior of the SSA was then compared with the numerical simulation results. Further, a series of impact tests were conducted to verify the performance of the SSA in the detection of the impact events from different directions. Comparison with the wave response associated with different faces of the cube verified the omnidirectional actuating and sensing capabilities of the SSA.

  20. 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.

  1. Removal of Zirconium in Electrometallurgical Treatment of Experimental Breeder Reactor II Spent Fuel

    SciTech Connect

    Ahluwalia, Rajesh K.; Hua, Thanh Q.; Geyer, Howard K.

    2001-01-15

    During electrorefining of irradiated, binary U-Zr Experimental Breeder Reactor II fuel, a portion of zirconium is found to dissolve along with uranium. It accumulates in the cadmium pool both as dissolved zirconium and as a zirconium-cadmium intermetallic precipitate. Two electrochemical methods of removing zirconium from the electrorefiner have been evaluated. The first is a three-step method consisting of chemical oxidation of zirconium by CdCl{sub 2} addition, depletion of zirconium from the cadmium pool by electrotransport, and drawdown of zirconium from the LiCl-KCl eutectic salt by using a different electrorefiner configuration. A transport model is employed to determine the cell operating conditions for growing pure zirconium deposits and the throughput rate. The second method eliminates the chemical oxidation step and permits codeposition of uranium and zirconium onto the solid cathode. The transport model is used to assess the level of uranium impurity in the cathode product; an additional step is proposed to reoxidize uranium in the deposit. The two methods are compared from the standpoints of throughput, deposit composition, deposit adherence to a solid cathode mandrel, and the underlying uncertainties. A brief review is given of the related past laboratory work on removal of zirconium from the electrorefiner.

  2. 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.

  3. Bis(methyl xanthato)-κS;κ2 S:S′-(triphenyl­phosphane-κP)palladium(II)

    PubMed Central

    Reyes-Martínez, Reyna; Hernández-Ortega, Simón; Morales-Morales, David

    2011-01-01

    The title compound, [Pd(C2H3OS2)2(C18H15P)], features a palladium complex with a triphenyl­phosphane ligand and two xanthate ligands, one of them coordinates in a bidentate and the other in a monodentate fashion, giving rise to a slightly distorted square-planar coordination of the PdII ion. As a result of this difference in the coordination modes, the C—S bond lengths are different, viz. 1.687 (2) and 1.692 (2) Å in the bidentate ligand and 1.723 (2) Å in the monodentate ligand, whereas the non-coordinating S atom has a C—S distance of 1.649 (2) Å. The crystal packing is stabilized by C—H⋯O inter­actions. PMID:22219766

  4. Bis[2,4-dibromo-6-(n-propyl-imino-methyl)phenolato-κN,O]cobalt(II).

    PubMed

    Li, Chunyan; Li, Rui; Zhang, Shufang

    2010-08-18

    In the title complex, [Co(C(10)H(10)Br(2)NO)(2)], the Co(II) atom lies on a twofold rotation axis, the N(2)O(2) units having distorted tetra-hedral coordination environments comprising two bidentate chelate 2,4-dibromo-6-(n-propyl-imino-meth-yl)phenolate Schiff base ligands [Co-N = 1.989 (3) Å, Co-O = 1.924 (2) Å and O/N-Co-O/N = 94.53 (10)-125.40 (15)°]. In the crystal structure, the mol-ecules are linked via weak inter-molecular C-H⋯O hydrogen bonds [3.334 (5) Å] and there are also short inversion-related intermolecular Br⋯Br contacts [3.4263 (6) Å].

  5. 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.

  6. Experimental and theoretical investigations of the rate constant for the reaction of the hydroxyl radical with methyl ethyl ketone

    NASA Astrophysics Data System (ADS)

    Vimal, D.; Stevens, P. S.

    2007-12-01

    Methyl ethyl ketone (MEK) or 2-butanone is a high-volume industrial solvent with a production rate greater than 70 million lbs yr-1. It is also a photo-oxidation product of several volatile organic compounds (VOCs) in the atmosphere. MEK is removed from the atmosphere primarily by its reaction with hydroxyl (OH) radical. As a result, knowledge of the chemical mechanism and temperature dependence of this reaction is important as MEK may be transported to the upper troposphere and influence the chemistry of this region of the atmosphere. We present absolute measurements of the rate constant and the kinetic isotope effect for the reaction of MEK with OH radicals at low pressure and over the temperature range 263-388 K using a discharge-flow technique coupled with resonance fluorescence detection of OH radicals. Theoretical studies of the potential energy surface suggest that the reaction of MEK and OH proceeds by H-abstraction mediated by the formation of a 7- membered hydrogen-bonded complex. This mechanism is similar to that of several other atmospherically relevant oxygenated VOCs such as acetone, acetic acid and hydroxyacetone. The influence of the pre-reactive complex on the temperature dependence for this reaction will be discussed.

  7. Microencapsulation of herbicide MCPA with native β-cyclodextrin and its methyl and hydroxypropyl derivatives: An experimental and theoretical investigation

    NASA Astrophysics Data System (ADS)

    Garrido, Jorge; Cagide, Fernando; Melle-Franco, Manuel; Borges, Fernanda; Garrido, E. Manuela

    2014-03-01

    When a pesticide is released into the environment, most of it is lost before it reaches its target. An effective way to reduce environmental losses of pesticides is by using controlled release technology. Microencapsulation becomes a promising technique for the production of controlled release agricultural formulations. In this work, the microencapsulation of chlorophenoxy herbicide MCPA with native β-cyclodextrin and its methyl and hydroxypropyl derivatives was investigated. The phase solubility study showed that both native and β-CD derivatives increased the water solubility of the herbicide and inclusion complexes are formed in a stoichiometric ratio of 1:1. The stability constants describing the extent of formation of the complexes have been determined by phase solubility studies. 1H NMR experiments were also accomplished for the prepared solid systems and the data gathered confirm the formation of the inclusion complexes. 1H NMR data obtained for the MCPA/CDs complexes disclosed noticeable proton shift displacements for OCH2 group and H6 aromatic proton of MCPA provided clear evidence of inclusion complexation process, suggesting that the phenyl moiety of the herbicide was included in the hydrophobic cavity of CDs. Free energy molecular mechanics calculations confirm all these findings.

  8. Optimization of photocatalytic degradation of methyl blue using silver ion doped titanium dioxide by combination of experimental design and response surface approach.

    PubMed

    Sahoo, C; Gupta, A K

    2012-05-15

    Photocatalytic degradation of methyl blue (MYB) was studied using Ag(+) doped TiO(2) under UV irradiation in a batch reactor. Catalytic dose, initial concentration of dye and pH of the reaction mixture were found to influence the degradation process most. The degradation was found to be effective in the range catalytic dose (0.5-1.5g/L), initial dye concentration (25-100ppm) and pH of reaction mixture (5-9). Using the three factors three levels Box-Behnken design of experiment technique 15 sets of experiments were designed considering the effective ranges of the influential parameters. The results of the experiments were fitted to two quadratic polynomial models developed using response surface methodology (RSM), representing functional relationship between the decolorization and mineralization of MYB and the experimental parameters. Design Expert software version 8.0.6.1 was used to optimize the effects of the experimental parameters on the responses. The optimum values of the parameters were dose of Ag(+) doped TiO(2) 0.99g/L, initial concentration of MYB 57.68ppm and pH of reaction mixture 7.76. Under the optimal condition the predicted decolorization and mineralization rate of MYB were 95.97% and 80.33%, respectively. Regression analysis with R(2) values >0.99 showed goodness of fit of the experimental results with predicted values.

  9. 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.

  10. The Eaf3/5/7 Subcomplex Stimulates NuA4 Interaction with Methylated Histone H3 Lys-36 and RNA Polymerase II.

    PubMed

    Sathianathan, Anish; Ravichandran, Priyadarshini; Lippi, Jake M; Cohen, Leah; Messina, Angelo; Shaju, Sherwin; Swede, Marci J; Ginsburg, Daniel S

    2016-09-30

    NuA4 is the only essential lysine acetyltransferase complex in Saccharomyces cerevisiae, where it has been shown to stimulate transcription initiation and elongation. Interaction with nucleosomes is stimulated by histone H3 Lys-4 and Lys-36 methylation, but the mechanism of this interaction is unknown. Eaf3, Eaf5, and Eaf7 form a subcomplex within NuA4 that may also function independently of the lysine acetyltransferase complex. The Eaf3/5/7 complex and the Rpd3C(S) histone deacetylase complex have both been shown to bind di- and trimethylated histone H3 Lys-36 stimulated by Eaf3. We investigated the role of the Eaf3/5/7 subcomplex in NuA4 binding to nucleosomes. Different phenotypes of eaf3/5/7Δ mutants support functions for the complex as both part of and independent of NuA4. Further evidence for Eaf3/5/7 within NuA4 came from mutations in the subcomplex leading to ∼40% reductions in H4 acetylation in bulk histones, probably caused by binding defects to both nucleosomes and RNA polymerase II. In vitro binding assays showed that Eaf3/5/7 specifically stimulates NuA4 binding to di- and trimethylated histone H3 Lys-36 and that this binding is important for NuA4 occupancy in transcribed ORFs. Consistent with the role of NuA4 in stimulating transcription elongation, loss of EAF5 or EAF7 resulted in a processivity defect. Overall, these results reveal the function of Eaf3/5/7 within NuA4 to be important for both NuA4 and RNA polymerase II binding. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  11. Experimental charge-density study of paracetamol - multipole refinement in the presence of a disordered methyl group

    NASA Astrophysics Data System (ADS)

    Bak, J. M.; Dominiak, P. M.; Wilson, C. C.; Wozniak, K.

    2009-11-01

    On the basis of high-resolution single-crystal X-ray diffraction data for paracetamol, different approaches (including those based on pseudoatom databases) to modeling of the static experimental electron density in the presence of a dynamically disordered molecular fragment were tested. The electrostatic properties obtained were compared with the results of theoretical single-point periodic calculations.

  12. Photodegradation of methyl orange and photoinactivation of bacteria by visible light activation of persulphate using a tris(2,2'-bipyridyl)ruthenium(II) complex.

    PubMed

    Subramanian, Gokulakrishnan; Parakh, Priyadarshini; Prakash, Halan

    2013-03-01

    Persulphate is an emerging oxidant in the field of advanced oxidation processes for the degradation of environmentally persistent organic compounds. The present study shows that visible light activation of persulphate (2 mM) using tris(2,2'-bipyridyl)ruthenium(II) (complex 1) (1 μM) caused rapid degradation (98%) of model azo dye methyl orange (MO) (12 mg L(-1)) with significant mineralization (76%), and also complete inactivation of both Gram negative and positive bacteria (∼10(7) CFU mL(-1)). BacLight LIVE/DEAD assay, scanning electron microscopy and genomic DNA analysis revealed cell membrane damage and loss of chromosomal DNA, indicating oxidative stress caused to E. coli during photoinactivation. The effect of concentration of complex 1 : persulphate ratio and presence of inorganic ions (0.1 M), such as sodium hydrogen phosphate, sodium sulphate, and sodium hydrogen carbonate, on the photodegradation of MO and photoinactivation of E. coli were studied. In addition, the effect of the presence of the organic contaminant resorcinol on the photoinactivation of E. coli was also studied. Significant degradation of MO and complete inactivation of bacteria were observed in simulated ground water. The present study is the first to reveal that activation of persulphate using a visible light absorbing metal complex in aqueous media has the ability to cause degradation of organic contaminants as well as complete inactivation of bacteria.

  13. A relative quantitative Methylation-Sensitive Amplified Polymorphism (MSAP) method for the analysis of abiotic stress.

    PubMed

    Bednarek, Piotr T; Orłowska, Renata; Niedziela, Agnieszka

    2017-04-21

    We present a new methylation-sensitive amplified polymorphism (MSAP) approach for the evaluation of relative quantitative characteristics such as demethylation, de novo methylation, and preservation of methylation status of CCGG sequences, which are recognized by the isoschizomers HpaII and MspI. We applied the technique to analyze aluminum (Al)-tolerant and non-tolerant control and Al-stressed inbred triticale lines. The approach is based on detailed analysis of events affecting HpaII and MspI restriction sites in control and stressed samples, and takes advantage of molecular marker profiles generated by EcoRI/HpaII and EcoRI/MspI MSAP platforms. Five Al-tolerant and five non-tolerant triticale lines were exposed to aluminum stress using the physiologicaltest. Total genomic DNA was isolated from root tips of all tolerant and non-tolerant lines before and after Al stress following metAFLP and MSAP approaches. Based on codes reflecting events affecting cytosines within a given restriction site recognized by HpaII and MspI in control and stressed samples demethylation (DM), de novo methylation (DNM), preservation of methylated sites (MSP), and preservation of nonmethylatedsites (NMSP) were evaluated. MSAP profiles were used for Agglomerative hierarchicalclustering (AHC) based on Squared Euclidean distance and Ward's Agglomeration method whereas MSAP characteristics for ANOVA. Relative quantitative MSAP analysis revealed that both Al-tolerant and non-tolerant triticale lines subjected to Al stress underwent demethylation, with demethylation of CG predominating over CHG. The rate of de novo methylation in the CG context was ~3-fold lower than demethylation, whereas de novo methylation of CHG was observed only in Al-tolerant lines. Our relative quantitative MSAP approach, based on methylation events affecting cytosines within HpaII-MspI recognition sequences, was capable of quantifying de novo methylation, demethylation, methylation, and non-methylated status in control

  14. 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.

  15. 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. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  16. 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.

  17. 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…

  18. Synthesis, crystal structure, DNA binding and photo-induced DNA cleavage activity of (S-methyl-L-cysteine)copper(II) complexes of heterocyclic bases.

    PubMed

    Patra, Ashis K; Nethaji, Munirathinam; Chakravarty, Akhil R

    2007-02-01

    Ternary S-methyl-L-cysteine (SMe-l-cys) copper(II) complexes [Cu(SMe-L-cys)(B)(H(2)O)](X) (1-4), where the heterocyclic base B is 2,2'-bipyridine (bpy, 1), 1,10-phenanthroline (phen, 2), dipyridoquinoxaline (dpq, 3) and dipyridophenazine (dppz, 4), and X is ClO(4)(-) (1-3) or NO(3)(-) (4), are prepared and their DNA binding and cleavage properties studied. Complexes 2 and 4 are structurally characterized by X-ray crystallography. Both the crystal structures show distorted square-pyramidal (4+1) CuN(3)O(2) coordination geometry of the complexes in which the N,O-donor S-methyl-L-cysteine and N,N-donor heterocyclic base bind at the basal plane with a water molecule as the axial ligand. In addition, the dppz structure shows the presence of a 1D-chain formed due to covalent linkage of the carboxylate oxygen atom belonging to another molecule at the elongated axial site. The crystal structures show chemically significant non-covalent interactions like hydrogen bonding involving the axial aqua ligand and pi-pi interactions between dppz ligands. The complexes display a d-d band in the range of 605-654 nm in aqueous dimethylformamide (DMF) solution (9:1 v/v). The redox active complexes show quasireversible cyclic voltammetric response near 0.1 V in DMF assignable to the Cu(II)/Cu(I) couple. The complexes show good binding affinity to calf thymus (CT) DNA giving the order: 4 (dppz)>3 (dpq)>2 (phen)>1 (bpy). The intrinsic binding constants, obtained from UV-visible spectroscopic studies, are 1.3x10(4) and 2.15 x 10(4) M(-1) for 3 and 4, respectively. Control DNA cleavage experiments using pUC19 supercoiled (SC) DNA and minor groove binder distamycin suggest major groove binding propensity for the dppz complex, while the phen and dpq complexes bind at the minor groove of DNA. Complexes 2-4 show DNA cleavage activity in dark in the presence of a reducing agent 3-mercaptopropionic acid (MPA) via a mechanistic pathway involving formation of hydroxyl radical as the reactive

  19. 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

  20. 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.

  1. Ferro- to antiferromagnetic crossover angle in diphenoxido- and carboxylato-bridged trinuclear Ni(II)₂-Mn(II) complexes: experimental observations and theoretical rationalization.

    PubMed

    Seth, Piya; Figuerola, Albert; Jover, Jesús; Ruiz, Eliseo; Ghosh, Ashutosh

    2014-09-02

    Three new trinuclear heterometallic Ni(II)-Mn(II) complexes have been synthesized using a [NiL] metalloligand, where H2L = N,N'-bis(salicylidene)-1,3-propanediamine. The complexes [(NiL)2Mn(OCnn)2(CH3OH)2]·CH3OH (1), [(NiL)2Mn(OPh)2(CH3OH)2][(NiL)2Mn(OPh)2]·H2O (2), and [(NiL)2Mn(OSal)2(CH3OH)2]·2[NiL] (3) (where OCnn = cinnamate, OPh = phenylacetate, OSal = salicylate) have been structurally characterized. In all three complexes, in addition to the double phenoxido bridge, the two terminal Ni(II) atoms are linked to the central Mn(II) by means of a syn-syn bridging carboxylate, giving rise to a linear structure. Complexes 1 and 2 with Ni-O-Mn angles of 97.24 and 96.43°, respectively, exhibit ferromagnetic interactions (J(Ni-Mn) = +1.38 and +0.50 cm(-1), respectively), whereas 3 is antiferromagnetic (J(Ni-Mn) = -0.24 cm(-1)), having an Ni-O-Mn angle of 98.51°. DFT calculations indicate that there is a clear magneto-structural correlation between the Ni-O-Mn angle and J(Ni-Mn) values, which is in agreement with the experimental results.

  2. Crystal structure of bis­(3,5-di­methyl­pyridine-κN)bis­(methanol-κO)bis­(thio­cyanato-κN)cobalt(II)

    PubMed Central

    Suckert, Stefan; Jess, Inke; Näther, Christian

    2016-01-01

    The asymmetric unit of the title complex, [Co(NCS)2(C7H9N)2(CH3OH)2], comprises of one CoII cation located on a centre of inversion, one thio­cyanate ligand, one methanol ligand and one 3,5-di­methyl­pyridine ligand. The CoII cation is octa­hedrally coordinated by two terminal N-bonding thio­cyanate anions, two methanol mol­ecules and two 3,5-di­methyl­pyridine ligands into a discrete complex. The complex mol­ecules are linked by inter­molecular O—H⋯S hydrogen bonding into chains that elongate in the direction parallel to the b axis. PMID:27980840

  3. MHC class II expression and potential antigen-presenting cells in the retina during experimental autoimmune uveitis.

    PubMed

    Lipski, Deborah A; Dewispelaere, Rémi; Foucart, Vincent; Caspers, Laure E; Defrance, Matthieu; Bruyns, Catherine; Willermain, François

    2017-07-18

    Controversy exists regarding which cell types are responsible for autoantigen presentation in the retina during experimental autoimmune uveitis (EAU) development. In this study, we aimed to identify and characterize the retinal resident and infiltrating cells susceptible to express major histocompatibility complex (MHC) class II during EAU. EAU was induced in C57BL/6 mice by adoptive transfer of autoreactive lymphocytes from IRBP1-20-immunized animals. MHC class II expression was studied by immunostainings on eye cryosections. For flow cytometry (FC) analysis, retinas were dissected and enzymatically digested into single-cell suspensions. Three MHC class II(+) retinal cell populations were sorted by FC, and their RNA processed for RNA-Seq. Immunostainings demonstrate strong induction of MHC class II expression in EAU, especially in the inner retina at the level of inflamed vessels, extending to the outer retinal layers and the subretinal space in severely inflamed eyes. Most MHC class II(+) cells express the hematopoietic marker IBA1. FC quantitative analyses demonstrate that MHC class II induction significantly correlates with disease severity and is associated with upregulation of co-stimulatory molecule expression. In particular, most MHC class II(hi) cells express co-stimulatory molecules during EAU. Further phenotyping identified three MHC class II(+) retinal cell populations: CD45(-)CD11b(-) non-hematopoietic cells with low MHC class II expression and CD45(+)CD11b(+) hematopoietic cells with higher MHC class II expression, which can be further separated into Ly6C(+) and Ly6C(-) cells, possibly corresponding to infiltrating macrophages and resident microglia. Transcriptome analysis of the three sorted populations leads to a clear sample clustering with some enrichment in macrophage markers and microglial cell markers in Ly6C(+) and Ly6C(-) cells, respectively. Functional annotation analysis reveals that both hematopoietic cell populations are more competent in

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

    PubMed Central

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

    2003-01-01

    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. PMID:14555813

  5. Synthesis and crystal structure of a dinuclear yttrium(III)- (lanthanide(III)-) copper(II) complex with an unusual 2-methyl-2,4,6-tris(trifluoromethyl)-1,3-dioxane-4,6-diolato ligand

    SciTech Connect

    Wang, S.; Pang, Z.; Smith, K.D.L. )

    1993-11-10

    A dinuclear Ln[sup III]-Cu[sup II] complex with an unusual 2-methyl-2,4,6-tris(trifluoromethyl)-1,3-dioxane-4,6-diolato ligand has been synthesized and characterized structurally. The 1,3-dioxane-4,6-diolato ligand is the product of cycloaddition of 1,1,1-trifluoro-2,2-propanediol to a hexafluoroacetylacetonato ligand promoted by the metal complex.

  6. 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.

  7. 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. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Virtual and experimental high-throughput screening (HTS) in search of novel inosine 5'-monophosphate dehydrogenase II (IMPDH II) inhibitors

    NASA Astrophysics Data System (ADS)

    Dunkern, Torsten; Prabhu, Arati; Kharkar, Prashant S.; Goebel, Heike; Rolser, Edith; Burckhard-Boer, Waltraud; Arumugam, Premkumar; Makhija, Mahindra T.

    2012-11-01

    IMPDH (Inosine 5'-monophosphate dehydrogenase) catalyzes a rate-limiting step in the de novo biosynthesis of guanine nucleotides. IMPDH inhibition in sensitive cell types (e.g., lymphocytes) blocks proliferation (by blocking RNA and DNA synthesis as a result of decreased cellular levels of guanine nucleotides). This makes it an interesting target for cancer and autoimmune disorders. Currently available IMPDH inhibitors such as mycophenolic acid (MPA, uncompetitive inhibitor) and nucleoside analogs (e.g., ribavirin, competitive inhibitor after intracellular activation by phosphorylation) have unfavorable tolerability profiles which limit their use. Hence, the quest for novel IMPDH inhibitors continues. In the present study, a ligand-based virtual screening using IMPDH inhibitor pharmacophore models was performed on in-house compound collection. A total of 50,000 virtual hits were selected for primary screen using in vitro IMPDH II inhibition up to 10 μM. The list of 2,500 hits (with >70 % inhibition) was further subjected to hit confirmation for the determination of IC50 values. The hits obtained were further clustered using maximum common substructure based formalism resulting in 90 classes and 7 singletons. A thorough inspection of these yielded 7 interesting classes in terms of mini-SAR with IC50 values ranging from 0.163 μM to little over 25 μM. The average ligand efficiency was found to be 0.3 for the best class. The classes thus discovered represent structurally novel chemotypes which can be taken up for further development.

  9. Two new isomeric zinc(II) metal-organic frameworks based on 1,5-bis(2-methyl-1H-imidazol-1-yl)pentane and 5-methylisophthalate ligands.

    PubMed

    Tan, Xiong Wen; Li, Heng Feng; Li, Chang Hong

    2017-02-01

    Many factors, such as temperature, solvent, the central metal atom and the type of coligands, may affect the nature of metal-organic frameworks (MOFs) and the framework formation in the self-assembly process, which results in the complexity of these compounds and the uncertainty of their structures. Two new isomeric Zn(II) metal-organic frameworks (MOFs) based on mixed ligands, namely, poly[[μ-1,5-bis(2-methyl-1H-imidazol-1-yl)pentane-κ(2)N(3):N(3')](μ-5-methylisophthalato-κ(2)O(1):O(3))zinc(II)], [Zn(C9H6O4)(C13H20N4)]n, (I), and poly[[μ-1,5-bis(2-methyl-1H-imidazol-1-yl)pentane-κ(2)N(3):N(3')](μ3-5-methylisophthalato-κ(3)O(1):O(1'):O(3))(μ3-5-methylisophthalato-κ(4)O(1):O(1'):O(3),O(3'))dizinc(II)], [Zn2(C9H6O4)2(C13H20N4)]n, (II), have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analysis and thermogravimetric analysis. Complex (I) displays a two-dimensional layer net, while complex (II) exhibits a twofold interpenetrating three-dimensional framework. Both complexes show high stability and good fluorescence in the solid state at room temperature.

  10. A theoretical and experimental investigation of the spectroscopic properties of a DNA-intercalator salphen-type Zn(II) complex.

    PubMed

    Biancardi, Alessandro; Burgalassi, Azzurra; Terenzi, Alessio; Spinello, Angelo; Barone, Giampaolo; Biver, Tarita; Mennucci, Benedetta

    2014-06-10

    The photophysical and DNA-binding properties of the cationic zinc(II) complex of 5-triethylammonium methyl salicylidene ortho-phenylenediiminato (ZnL(2+)) were investigated by a combination of experimental and theoretical methods. DFT calculations were performed on both the ground and the first excited states of ZnL(2+) and on its possible mono- and dioxidation products, both in vacuo and in selected solvents mimicked by the polarizable continuum model. Comparison of the calculated absorption and fluorescence transitions with the corresponding experimental data led to the conclusion that visible light induces a two-electron photooxidation process located on the phenylenediiminato ligand. Kinetic measurements, performed by monitoring absorbance changes over time in several solvents, are in agreement with a slow unimolecular photooxidation process, which is faster in water and slower in less polar solvents. Moreover, structural details of ZnL-DNA binding were obtained by DFT calculations on the intercalation complexes between ZnL and the d(ApT)2 and d(GpC)2 dinucleoside monophosphate duplexes. Two main complementary binding interactions are proposed: 1) intercalation of the central phenyl ring of the ligand between the stacked DNA base pairs; 2) external electrostatic attraction between the negatively charged phosphate groups and the two cationic triethylammonium groups of the Schiff-base ligand. Such suggestions are supported by fluorescence titrations performed on the ZnL/DNA system at different ionic strengths and temperatures. In particular, the values of the DNA-binding constants obtained at different temperatures provided the enthalpic and entropic contributions to the binding and confirmed that two competitive mechanisms, namely, intercalation and external interaction, are involved. The two mechanisms are coexistent at room temperature under physiological conditions.

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

    NASA Astrophysics Data System (ADS)

    Yurdakul, Şenay; Badoğlu, Serdar; Güleşci, Yeliz

    2015-02-01

    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.

  12. Off-normal performance of EBR-II (Experimental Breeder Reactor) driver fuel

    SciTech Connect

    Seidel, B.R.; Batte, G.L.; Lahm, C.E.; Fryer, R.M.; Koenig, J.F.; Hofman, G.L.

    1986-09-01

    The off-normal performance of EBR-II Mark-II driver fuel has been more than satisfactory as demonstrated by robust reliability under repeated transient overpower and undercooled loss-of-flow tests, by benign run-beyond-cladding-breach behavior, and by forgiving response to fabrication defects including lack of bond. Test results have verified that the metallic driver fuel is very tolerant of off-normal events. This behavior has allowed EBR-II to operate in a combined steady-state and transient mode to provide test capability without limitation from the metallic driver fuel.

  13. Pd(II) and Pd(IV) complexes with 5-methyl-5-(4-pyridyl)hydantoin: Synthesis, physicochemical, theoretical, and pharmacological investigation

    NASA Astrophysics Data System (ADS)

    Sabounchei, Seyyed Javad; Shahriary, Parisa; Salehzadeh, Sadegh; Gholiee, Yasin; Nematollahi, Davood; Chehregani, Abdolkarim; Amani, Ameneh; Afsartala, Zohreh

    2015-01-01

    The reaction of K2[PdCl4] and PdCl2 with 5-methyl-5-(4-pyridyl)-2,4-imidazolidenedione (L) proceeded with the formation of two different Pd complexes, PdL2Cl2 (1) and PdL2Cl4 (2c), corresponded to a substitution reaction and a substitution reaction along with unanticipated oxidation, respectively. The nature of the oxidizing agent is unknown. These compounds have been studied by elemental analysis, IR, 1H and 13CNMR, molar conductivity, and cyclic voltammetry. In addition, structural optimization by DFT calculations and simulation of NMR spectra have been performed and compared with the experimental data. NBO analysis, HOMO and LUMO, have been used to elucidate the information regarding charge transfer within the molecules. Theoretical studies confirmed that in 1 and 2c the trans structures are about 41 and 33 kJ mol-1 more stable than cis ones. Antibacterial activity and in vitro cytotoxicity of these compounds, as respectively assessed in six bacterial strains and two human tumor cell lines, have been investigated. Results showed the title complexes have the capacity of inhibiting the metabolic growth of bacteria and tumor cells to different extents.

  14. Synthesis, spectroscopic studies and structures of square-planar nickel(II) and copper(II) complexes derived from 2-{(Z)-[furan-2-ylmethyl]imino]methyl}-6-methoxyphenol.

    PubMed

    Unver, Hüseyin; Hayvali, Zeliha

    2010-02-01

    Two new nickel(II) [Ni(L)(2)] and copper(II) [Cu(L)(2)] complexes have been synthesized with bidentate NO donor Schiff base ligand (2-{(Z)-[furan-2-ylmethyl]imino]methyl}-6-methoxyphenol) (HL) and both complexes Ni(L)(2) and Cu(L)(2) have been characterized by elemental analyses, IR, UV-vis, (1)H, (13)C NMR, mass spectroscopy and room temperature magnetic susceptibility measurement. The tautomeric equilibria (phenol-imine, O-H...N and keto-amine, O...H-N forms) have been systemetically studied by using UV-vis absorption spectra for the ligand HL. The UV-vis spectra of this ligand HL were recorded and commented in polar, non-polar, acidic and basic media. The crystal structures of these complexes have also been determined by using X-ray crystallographic techniques. The complexes Ni(L)(2) and Cu(L)(2) crystallize in the monoclinic space group P2(1)/n and P2(1)/c with unit cell parameters: a=10.4552(3)A and 12.1667(4)A, b=8.0121(3)A and 10.4792(3)A, c=13.9625(4)A and 129.6616(3)A, V=1155.22(6)A(3) and 1155.22(6)A(3), D(x)=1.493 and 1.476 g cm(-3) and Z=2 and 2, respectively. The crystal structures were solved by direct methods and refined by full-matrix least squares to a find R=0.0377 and 0.0336 of for 2340 and 2402 observed reflections, respectively.

  15. 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.

  16. 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.

  17. 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)

  18. 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)

  19. An analytical and experimental stress analysis of a practical mode II fracture-test specimen

    NASA Technical Reports Server (NTRS)

    Chisholm, D. B.; Jones, D. L.

    1975-01-01

    A boundary collocation method has been employed to determine the Mode II stress intensity factors for a pair of through-the-thickness edge cracks in a finite isotropic plate. An elastostatic analysis has been carried out in terms of the complete Williams stress function employing both even and odd components. The results of the numerical analysis were verified by a two-step procedure whereby the symmetric and antisymmetric portions of the solution were independently compared with existing solutions. The complete solution was verified by comparison with a photoelastic analysis. A compact shear specimen (CSS) of Hysol epoxy resin was loaded in a photoelastic experiment designed to study the isochromatic fringe patterns resulting from the Mode II crack tip stress distribution. The experiment verified that a pure Mode II stress distribution existed in the neighborhood of the crack tips and confirmed the accuracy of the boundary collocation solution for the Mode II stress intensity factors.

  20. Experimental study on NO oxidation by K2S2O8 + Fe(II)EDTA

    NASA Astrophysics Data System (ADS)

    Hu, Hui; Huang, Hao; Tao, Gong-Kai; Xie, Jing; Yang, Cheng; Huang, Ting

    2017-06-01

    NO absorption and oxidation by K2S2O8 + Fe(II)EDTA system was studied in a lab-scale bubble reactor. The effects of different additives, reaction temperatures, pH values, K2S2O8 and Fe(II)EDTA concentrations on NO conversion were systematic investigated. Results indicated that NO conversion rate of K2S2O8 + Fe(II)EDTA system increased to 91.6% when concentrations of K2S2O8 and Fe(II)EDTA were both 30 mmol/L at 80 °C. NO conversion rate was positively correlated with the SO42- concentration in absorption solution, and it kept around 80% in a wide pH range, which made this technology to be a promising method for the denitrification of coal-fired flue gas.

  1. An analytical and experimental stress analysis of a practical mode II fracture-test specimen

    NASA Technical Reports Server (NTRS)

    Chisholm, D. B.; Jones, D. L.

    1975-01-01

    A boundary collocation method has been employed to determine the Mode II stress intensity factors for a pair of through-the-thickness edge cracks in a finite isotropic plate. An elastostatic analysis has been carried out in terms of the complete Williams stress function employing both even and odd components. The results of the numerical analysis were verified by a two-step procedure whereby the symmetric and antisymmetric portions of the solution were independently compared with existing solutions. The complete solution was verified by comparison with a photoelastic analysis. A compact shear specimen (CSS) of Hysol epoxy resin was loaded in a photoelastic experiment designed to study the isochromatic fringe patterns resulting from the Mode II crack tip stress distribution. The experiment verified that a pure Mode II stress distribution existed in the neighborhood of the crack tips and confirmed the accuracy of the boundary collocation solution for the Mode II stress intensity factors.

  2. 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.

  3. 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.

  4. Cysteine Inhibits Mercury Methylation by Geobacter sulfurreducens PCA Mutant Δ omcBESTZ

    DOE PAGES

    Lin, Hui; Lu, Xia; Liang, Liyuan; ...

    2015-04-21

    For cysteine enhances Hg uptake and methylation by Geobacter sulfurreducens PCA wild type (WT) strain in short-term assays. The prevalence of this enhancement in other strains remains poorly understood. We examined the influence of cysteine concentration on time-dependent Hg(II) reduction, sorption and methylation by PCA-WT and its c-type cytochrome-deficient mutant ( omcBESTZ) in phosphate buffered saline. Without cysteine, the mutant methylated twice as much Hg(II) as the PCA-WT, whereas addition of cysteine inhibited Hg methylation, regardless of the reaction time. PCA-WT, but, exhibited both time-dependent and cysteine concentration-dependent methylation. In 144 hour assay, nearly complete sorption of the Hg(II) bymore » PCA-WT occurred in the presence of 1 mM cysteine, resulting in our highest observed methylmercury production. Moreover, the chemical speciation modeling and experimental data suggest that uncharged Hg(II) species are more readily taken up, and that this uptake is kinetic limiting, thereby affecting Hg methylation by both mutant and WT.« less

  5. Sound conversion phenomena at the free surface of liquid helium. II. Experimental determination of acoustic coefficients and surface absorption coefficients

    NASA Astrophysics Data System (ADS)

    Wiechert, H.; Buchholz, F. I.

    1983-05-01

    The acoustic coefficients of reflection, transmission, and transformation of first-, second-, and gas sound waves incident normally on the free surface of liquid helium have been determined. The experimental results are compared with the theory developed in Part I of this paper. It is shown that equilibrium theories of boundary conditions disagree with the experiments. Nonequilibrium theories, however, which take into account that mass and energy transport processes occur at the liquid-vapor interface of helium II, lead to a very good description of the experimental data below 2 K. Within experimental accuracy the measurements fully confirm several kinetic models of evaporation and energy transport processes. Near the λ point, deviations from the theory have been found which might be attributed to influences of critical phenomena. The surface absorption coefficients of first-, second-, and gas sound waves could be deduced from the experimental data on the acoustic coefficients, and it is shown that, in agreement with the theory, appreciable energy dissipation occurs at the free surface of helium II when a second-sound or a gas sound wave is incident.

  6. 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

    2016-01-05

    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.

  7. 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.

  8. Experimental and Numerical Study on Effect of Sample Orientation on Auto-Ignition and Piloted Ignition of Poly(methyl methacrylate)

    PubMed Central

    Peng, Fei; Zhou, Xiao-Dong; Zhao, Kun; Wu, Zhi-Bo; Yang, Li-Zhong

    2015-01-01

    In this work, the effect of seven different sample orientations from 0° to 90° on pilot and non-pilot ignition of PMMA (poly(methyl methacrylate)) exposed to radiation has been studied with experimental and numerical methods. Some new and significant conclusions are drawn from the study, including a U-shape curve of ignition time and critical mass flux as sample angle increases for pilot ignition conditions. However, in auto-ignition, the ignition time and critical mass flux increases with sample angle α. Furthermore, a computational fluid dynamic model have been built based on the Fire Dynamics Simulator (FDS6) code to investigate the mechanisms controlling the dependence on sample orientation of the ignition of PMMA under external radiant heating. The results of theoretical analysis and modeling results indicate the decrease of total incident heat flux at sample surface plays the dominant role during the ignition processes of auto-ignition, but the volatiles gas flow has greater influence for piloted ignition conditions. PMID:28793421

  9. Diethylalkylsulfonamido(4-methoxyphenyl)methyl)phosphonate/phosphonic acid derivatives act as acid phosphatase inhibitors: synthesis accompanied by experimental and molecular modeling assessments.

    PubMed

    Alimoradi, Nahid; Ashrafi-Kooshk, Mohammad Reza; Shahlaei, Mohsen; Maghsoudi, Shabnam; Adibi, Hadi; McGeary, Ross P; Khodarahmi, Reza

    2017-12-01

    Purple acid phosphatases (PAPs) are binuclear metallo-hydrolases that have been isolated from various mammals, plants, fungi and bacteria. In mammals, PAP activity is associated with bone resorption and can lead to bone metabolic disorders such as osteoporosis; thus human PAP is an attractive target to develop anti-osteoporotic drugs. The aim of the present study was to investigate inhibitory effect of synthesized diethylalkylsulfonamido(4-methoxyphenyl)methyl)phosphonate/phosphonic acid derivatives as potential red kidney bean PAP (rkbPAP) inhibitors accompanied by experimental and molecular modeling assessments. Enzyme kinetic data showed that they are good rkbPAP inhibitors whose potencies improve with increasing alkyl chain length. Hexadecyl derivatives, as most potent compounds (Ki = 1.1 µM), inhibit rkbPAP in the mixed manner, while dodecyl derivatives act as efficient noncompetitive inhibitor. Also, analysis by molecular modeling of the structure of the rkbPAP-inhibitor complexes reveals factors, which may be important for the determination of inhibition specificity.

  10. Experimental and Numerical Study on Effect of Sample Orientation on Auto-Ignition and Piloted Ignition of Poly(methyl methacrylate).

    PubMed

    Peng, Fei; Zhou, Xiao-Dong; Zhao, Kun; Wu, Zhi-Bo; Yang, Li-Zhong

    2015-07-02

    In this work, the effect of seven different sample orientations from 0° to 90° on pilot and non-pilot ignition of PMMA (poly(methyl methacrylate)) exposed to radiation has been studied with experimental and numerical methods. Some new and significant conclusions are drawn from the study, including a U-shape curve of ignition time and critical mass flux as sample angle increases for pilot ignition conditions. However, in auto-ignition, the ignition time and critical mass flux increases with sample angle α. Furthermore, a computational fluid dynamic model have been built based on the Fire Dynamics Simulator (FDS6) code to investigate the mechanisms controlling the dependence on sample orientation of the ignition of PMMA under external radiant heating. The results of theoretical analysis and modeling results indicate the decrease of total incident heat flux at sample surface plays the dominant role during the ignition processes of auto-ignition, but the volatiles gas flow has greater influence for piloted ignition conditions.

  11. Spectra, electronic structure and molecular docking investigations on 3-(phenyl(p-tolylamino)methyl)naphthalen-2-ol - An experimental and computational approach

    NASA Astrophysics Data System (ADS)

    Pradeepa, S. Jone; Boobalan, Maria Susai; Tamilvendan, D.; Sundaraganesan, N.; Sebastian, S.; Qian, Kun

    2017-05-01

    A combined experimental and theoretical study on synthesis, molecular structure, vibrational analysis, natural bond orbitals, electronic structure, hyperpolarizability, thermochemical properties has been reported for 3-(phenyl(p-tolylamino)methyl) naphthalen-2-ol (PTMN). The FT-IR spectrum was recorded in the range 4000-400 cm-1 and FT-Raman spectrum was recorded in the range 4000-50 cm-1. Sadlej pVTZ basis set was used to calculate the molecular geometry and the vibrational spectra. Natural bond orbital analysis (NBO) were calculated for PTMN using Density Functional Theory (DFT) based on B3LYP/6-311G(d,p) model chemistry. The potential energy distribution (PED) was derived to deepen the understanding on different modes of vibrations which are contributed by respective wavenumber. The molecular structure of PTMN was confirmed also with the simulation of NMR spectrum was performed using GIAO strategy by using B3LYP/6-311G(d,p). The non-linear nature of PTMN was confirmed by hyperpolarizabilty examination. The docking results suggest that the PTMN might exhibit inhibitory activity against protein induce Alopecia disease. The experimental UV-Visible spectra was recorded in the region of 600-200 nm and correlated with simulated spectra by suitable solvated PBEPBE/6-311G(d,p) model. The properties of HOMO-LUMO energies were measured by DFT approaches. In addition, the molecular electrostatic potential (MEP) was computed and investigated. Thermal properties are theoretically calculated that are obtained from the thermochemistry results against a range of temperatures.

  12. 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.

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

    USDA-ARS?s Scientific Manuscript database

    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...

  14. 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)

  15. 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)

  16. Poly[[di-aqua-deca-μ2-cyanido-κ(20) C:N-hexa-cyanido-κ(6) C-bis-(μ2-5-methyl-pyrimidine-κ(2) N:N')bis-(5-methyl-pyrimidine-κN)tricopper(II)ditungstate(V)] dihydrate].

    PubMed

    Tsunobuchi, Yoshihide; Kaneko, Souhei; Nakabayashi, Koji; Ohkoshi, Shin-Ichi

    2014-02-01

    In the title complex, {[Cu3[W(CN)8]2(C5H6N2)4(H2O)2]·2H2O} n , the coordination polyhedron of the eight-coordinated W(V) atom is a bicapped trigonal prism, in which five CN groups are bridged to Cu(II) ions, and the other three CN groups are terminally bound. Two of the Cu(II) ions lie on a centre of inversion and each of the three independent Cu(II) cations is pseudo-octahedrally coordinated. In the crystal structure, cyanido-bridged-Cu-W-Cu layers are linked by pillars involving the third independent Cu(II) ion, generating a three-dimensional network with non-coordinating water mol-ecules and 5-methyl-pyrimidine mol-ecules. O-H⋯O and O-H⋯N hydrogen bonds involve the coordinating and non-coordin-ating water mol-ecules, the CN groups and the 5-methyl-pyrimidine mol-ecules.

  17. 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…

  18. 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.

  19. 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…

  20. Characterization of potential NMDA and cholecystokinin antagonists. II. Lipophilicity studies on 2-methyl-4-oxo-3H-quinazoline-3-alkyl-carboxylic acid derivatives.

    PubMed

    Almási, J; Takács-Novák, K; Kökösi, J; Vámos, J

    1999-03-25

    The lipophilicity of 17 newly synthesized potential NMDA and cholecystokinin antagonist 2-methyl-4-oxo-3H-quinazoline-3-alkyl-carboxylic acid derivatives has been investigated. The apparent partition coefficients of two amphoteric compounds of overlapping protonation (Q1 and Q2) were determined by shake-flask method and converted into true log P values using the protonation microconstants. The difference between their lipophilicity expressed with the true partition coefficients was less, than it could be expected from the 2D structures and was explained with conformational preferences and formation of intramolecular interactions. Out of the other 15 monoprotic quinazolone compounds the lipophilicity of ten molecules (Q8-Q17, experimental set) was determined by TLC method with the help of a calibration set consisting of 12 standard molecules, five quinazolones (Q3-Q7) and seven pyrido[1,2-a]pyrimidines (PP1-PP7). In order to justify the suitability of pyrido-pyrimidines as standards for the chromatographic log P determination of quinazolones, first Q3-Q7 were examined by TLC and HPLC using PP1-PP7 for calibration. Data showed good agreement of results obtained by shake-flask and two different chromatographic methods indicating the similar chromatographic behavior of the two bicyclic systems and the relevance of PP1-PP7 to extend the calibration set of quinazolones. The obtained log P values proved mostly the expected structure-activity relationships. Some findings, however, have revealed specific partition behavior of the compounds providing useful information in the estimation of their pharmacokinetics, and these are discussed in the paper.

  1. 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

  2. Syntheses, structures, and properties of two new zinc(II) metal-organic frameworks based on flexible 1,6-bis(2-methyl-imidazole-1-yl)hexane ligand

    NASA Astrophysics Data System (ADS)

    Jin, Jun-Cheng; Fu, Ai-Yun; Li, Dian; Chang, Wen-Gui; Wu, Ju; Yang, Mei; Xie, Cheng-Gen; Xu, Guang-Nian; Cai, An-Xing; Wu, Ai-Hua

    2014-11-01

    Two new zinc(II) metal-organic compounds of [Zn(ADC)(bimh)]n (1) and [Zn(ADA)(bimh)]n (2) (H2ADC = 1,3-adamantanedicarboxylic acid, H2ADA = 1,3-adamantanediacetic acid, bimh = 1,6-bis(2-methyl-imidazole-1-yl)-hexane, have been structurally characterized by X-ray diffraction analysis. In compound 1, the zinc(II) ions are bridged by ADC and bimh ligands to form a 1D looped chain. In compound 2, the ADA molecules alternately bridge Zn(II) atoms to form infinite chains, and then the 1D chain is connected through the bimh ligand resulting in an undulating infinite two-dimensional (2D) polymeric network. Additionally, TG analysis, XRPD and fluorescent properties for compounds 1 and 2 are also measured and discussed.

  3. Crystal structure of hexa-aqua-nickel(II) bis-{5-bromo-7-[(2-hy-droxy-eth-yl)amino]-1-methyl-6-oxido-quinolin-1-ium-3-sulfonate} monohydrate.

    PubMed

    Le Thi Hong, Hai; Nguyen Thi Ngoc, Vinh; Do Thi Van, Anh; Van Meervelt, Luc

    2016-09-01

    The asymmetric unit of the title compound, [Ni(H2O)6](C12H12BrN2O5S)2·H2O, contains a half hexa-aqua-nickel(II) complex cation with the Ni(II) ion lying on an inversion center, one 5-bromo-7-[(2-hy-droxy-eth-yl)amino]-1-methyl-6-oxido-quinolin-1-ium-3-sulfonate (QAO) anion and a half lattice water mol-ecule on a twofold rotation axis. In the crystal, QAO anions are stacked in a column along the c axis by π-π stacking inter-actions [centroid-centroid distances 3.5922 (10)-3.7223 (11) Å]. The columns are inter-linked by hexa-aqua-nickel(II) cations through O-H⋯O and N-H⋯O hydrogen bonds.

  4. Analysis of Software Development Methodologies to Build Safety Software Applications for the SATEX-II: A Mexican Experimental Satellite

    NASA Astrophysics Data System (ADS)

    Aguilar Cisneros, Jorge; Vargas Martinez, Hector; Pedroza Melendez, Alejandro; Alonso Arevalo, Miguel

    2013-09-01

    Mexico is a country where the experience to build software for satellite applications is beginning. This is a delicate situation because in the near future we will need to develop software for the SATEX-II (Mexican Experimental Satellite). SATEX- II is a SOMECyTA's project (the Mexican Society of Aerospace Science and Technology). We have experienced applying software development methodologies, like TSP (Team Software Process) and SCRUM in other areas. Then, we analyzed these methodologies and we concluded: these can be applied to develop software for the SATEX-II, also, we supported these methodologies with SSP-05-0 Standard in particular with ESA PSS-05-11. Our analysis was focusing on main characteristics of each methodology and how these methodologies could be used with the ESA PSS 05-0 Standards. Our outcomes, in general, may be used by teams who need to build small satellites, but, in particular, these are going to be used when we will build the on board software applications for the SATEX-II.

  5. A new example of intra-molecular C-H⋯Ni anagostic inter-actions: synthesis, crystal structure and Hirshfeld analysis of cis-bis-[4-methyl-2-(1,2,3,4-tetra-hydro-naphthalen-1-yl-idene)hydrazinecarbo-thio-amidato-κ(2)N(1),S]nickel(II) di-methyl-formamide monosolvate.

    PubMed

    de Oliveira, Adriano Bof; Beck, Johannes; Mellone, Sônia Elizabeth Brown S; Daniels, Jörg

    2017-06-01

    The reaction of Ni(II) acetate tetra-hydrate with 4-methyl-2-(1,2,3,4-tetra-hydro-naphthalen-1-yl-idene)hydrazinecarbo-thio-amide in a 2:1 molar ratio and recrystallization from di-methyl-formamide yielded the title compound, [Ni(C12H14N3S)2]·C3H7NO. The ligands act as monoanionic κ(2)N(1),S-donors, forming five-membered metallarings. The Ni(II) ion is fourfold coordinated in a distorted square-planar cis-configuration, which is rather uncommon for mono-thio-semicarbazone complexes. Intra-molecular H⋯Ni trans-inter-actions are observed [H⋯Ni distances are 2.50 and 2.57 Å] and thus anagostic inter-actions can be suggested. The Hirshfeld surface analysis indicates that the major contributions for the crystal packing are H⋯H (66.6%), H⋯S (12.3%) and H⋯C (10.9%) inter-actions. In the crystal, the complex mol-ecules are linked by di-methyl-formamide solvent mol-ecules through N-H⋯O inter-actions into one-dimensional hydrogen-bonded polymers along [010].

  6. Tetra-2,3-pyrazinoporphyrazines with externally appended pyridine rings. 4. UV-visible spectral and electrochemical evidence of the remarkable electron-deficient properties of the new tetrakis-2,3-[5,6-di{2-(N-methyl)pyridiniumyl}pyrazino]porphyrazinatometal octacations, [(2-Mepy)8TPyzPzM]8+ (M = MgII(H2O), CoII, CuII, ZnII).

    PubMed

    Bergami, Costanza; Donzello, Maria Pia; Monacelli, Fabrizio; Ercolani, Claudio; Kadish, Karl M

    2005-12-26

    Metal derivatives of the octacationic tetrakis-2,3-[5,6-di{2-(N-methyl)pyridiniumyl}pyrazino]porphyrazine macrocycle [(2-Mepy)(8)TPyzPzH(2)](8+) (2-Mepy = 2-(N-methyl)pyridiniumyl ring) isolated as water-soluble hydrated iodide salts of the general formula [(2-Mepy)(8)TPyzPzM](I(8)).xH(2)O, (M = Mg(II)(H(2)O), Co(II), Cu(II), Zn(II); x = 2-5) were prepared from the corresponding neutral complexes [Py(8)TPyzPzM].xH(2)O previously reported. Reaction of these complexes with CH(3)I in N,N-dimethylformamide under mild conditions led to full quaternization of all eight pyridine N atoms and formation of the octacations [(2-Mepy)(8)TPyzPzM](8+). Clathrated water molecules could be eliminated from the species [(2-Mepy)(8)TPyzPzM](I(8)).xH(2)O by mild heating (II) and Co(II) complexes in the solid state are both paramagnetic with one unpaired electron, thus giving a low-spin state Co(II) for the latter compound. Studies of the charged species [(2-Mepy)(8)TPyzPzM](8+) in aqueous media at ca. 10(-)(5) M concentration provide evidence for the occurrence of molecular aggregation, similar to what is seen for the related free-base species [(2-Mepy)(8)TPyzPzH(2)](8+) (see part 3 of this series, preceding paper in this issue), but the formation of monomeric species is generally favored upon dilution of the solutions. The same octacations are essentially monomeric in solutions of pyridine or dimethyl sulfoxide (DMSO), but traces of aggregation, if occasionally present, vanish with the time. Changes in the UV-visible spectra are observed in the Q- and B-band regions as a result of the quaternization at the pyridine N atoms. Cyclic voltammetry and thin-layer spectroelectrochemical data in DMSO show well-resolved reversible multistep one-electron reductions for both the unmethylated and methylated

  7. Synthesis, experimental and theoretical characterizations of a new Schiff base derived from 2-pyridincarboxaldehyde and its Ni (II) complex

    NASA Astrophysics Data System (ADS)

    Habibi, Mohammad; Beyramabadi, S. Ali; Allameh, Sadegh; Khashi, Maryam; Morsali, Ali; Pordel, Mehdi; Khorsandi-Chenarboo, Mahdi

    2017-09-01

    In this work, a tridentate Schiff base of 2-pyridinecarboxaldehyde and its Ni(II) complex have been newly synthesized and characterized by the IR and NMR spectroscopies together with the elemental analysis. In addition, optimized geometries, the Natural Bond Orbital (NBO) analyses, assignment of the IR bands and NMR chemical shifts of the synthesized compounds were computed by using density functional theory (DFT) methods. In the optimized geometry of the free ligand, the aromatic rings are not in the same plane. But, the Ni complex is square planar, where the deprotonated Schiff base acts as a N3-tridentate ligand. The chloro ligand occupies another coordination position of the complex. The DFT-calculated vibrational wavenumbers and NMR chemical shifts are in agreement with the experimental values, confirming suitability of the optimized geometries for the Schiff base and Ni(II) complex.

  8. Horizontal transfer of DNA methylation patterns into bacterial chromosomes.

    PubMed

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

    2016-05-19

    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. © The Author(s) 2016. Published by Oxford University Press on behalf of Nucleic Acids Research.

  9. [Computers in biomedical research II: experimental control, data acquisition and storage].

    PubMed

    Maldonado, P; Vivaldi, E

    2001-09-01

    During the last decade, there has been a significant increase in the use of computers in biomedical research. In particular, the use of these instruments in experimental control, as well as in the acquisition and storage of experimental data, has become universal. The current capacity of these machines enables the precise manipulation of many experimental variables and allows for very fast acquisition of data. In this article, we discuss the fundamentals of small personal computers and its use in experimental control and data acquisition. Further, we discuss technical aspects related to the management of measurement instrument's control and their technical limitations. Electrical recordings from the cerebral cortex are used as examples to illustrate the different aspect included in this article.

  10. 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).

  11. Response surface modeling of Pb(II) removal from aqueous solution by Pistacia vera L.: Box-Behnken experimental design.

    PubMed

    Yetilmezsoy, Kaan; Demirel, Sevgi; Vanderbei, Robert J

    2009-11-15

    A three factor, three-level Box-Behnken experimental design combining with response surface modeling (RSM) and quadratic programming (QP) was employed for maximizing Pb(II) removal from aqueous solution by Antep pistachio (Pistacia vera L.) shells based on 17 different experimental data obtained in a lab-scale batch study. Three independent variables (initial pH of solution (pH(0)) ranging from 2.0 to 5.5, initial concentration of Pb(II) ions (C(0)) ranging from 5 to 50 ppm, and contact time (t(C)) ranging from 5 to 120 min) were consecutively coded as x(1), x(2) and x(3) at three levels (-1, 0 and 1), and a second-order polynomial regression equation was then derived to predict responses. The significance of independent variables and their interactions were tested by means of the analysis of variance (ANOVA) with 95% confidence limits (alpha=0.05). The standardized effects of the independent variables and their interactions on the dependent variable were also investigated by preparing a Pareto chart. The optimum values of the selected variables were obtained by solving the quadratic regression model, as well as by analysing the response surface contour plots. The optimum coded values of three test variables were computed as x(1)=0.125, x(2)=0.707, and x(3)=0.107 by using a LOQO/AMPL optimization algorithm. The experimental conditions at this global point were determined to be pH(0)=3.97, C(0)=43.4 ppm, and t(C)=68.7 min, and the corresponding Pb(II) removal efficiency was found to be about 100%.

  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 evidence of ion-induced instabilities in the NSLS-II storage ring

    NASA Astrophysics Data System (ADS)

    Cheng, Weixing; Li, Yongjun; Podobedov, Boris

    2017-07-01

    Fast ion instability has been identified as one of the most prominent instabilities in the recently constructed NSLS-II storage ring at Brookhaven National Laboratory. At a relatively low beam current ( 25 mA) multi-bunch fills, ion-induced instabilities have already been observed during the early stages of machine commissioning. At present user operation with 250 mA in 1000 bunches, the fast ion still remains the dominant instability, even after months of vacuum conditioning at high current. Ion-induced dipole motions of the electron beam have been suppressed using the transverse bunch-by-bunch (BxB) feedback system. However other adverse effects of this instability, such as the vertical beam size increase along the bunch train cannot be cured by the feedback system. Therefore, to achieve the NSLS-II design current of 500 mA while maintaining a small vertical beam emittance, it is important to further understand the fast ion instability and develop mitigation techniques. This paper reports on a series of ion-instability observations at various fill patterns and beam currents using start-of-art NSLS-II diagnostic tools.

  14. 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

  15. A new two-dimensional Cd(II) coordination polymer based on 2-(1H-imidazol-1-ylmethyl)-6-methyl-1H-benzimidazole and benzene-1,2-dicarboxylate: synthesis, crystal structure and characterization.

    PubMed

    Yang, Huai Xia; Yang, Yan Qiu; Cheng, Di; Li, Ya Xue; Meng, Xiang Ru

    2017-10-01

    In the construction of coordination polymers, many factors can influence the formation of the final architectures, such as the nature of the metal centres, the organic ligands and the counter-anions. In the coordination polymer poly[aqua(μ-benzene-1,2-dicarboxylato-κ(4)O(1),O(1'):O(2),O(2'))[μ-2-(1H-imidazol-1-ylmethyl)-6-methyl-1H-benzimidazole-κ(2)N(2):N(3)]cadmium(II)], [Cd(C12H12N4)(C8H4O4)(H2O)]n or [Cd(immb)(1,2-bdic)(H2O)]n, each Cd(II) ion is seven-coordinated by two N atoms from two symmetry-related 2-(1H-imidazol-1-ylmethyl)-6-methyl-1H-benzimidazole (immb) ligands, by four O atoms from two symmetry-related benzene-1,2-dicarboxylate (1,2-bdic(2-)) ligands and by one water molecule, leading to a CdN2O5 distorted pentagonal bipyramidal coordination environment. The immb and 1,2-bdic(2-) ligands bridge Cd(II) ions and form a two-dimensional network structure. O-H...O and N-H...O hydrogen bonds stabilize the structure. In addition, the IR spectroscopic properties, PXRD patterns, thermogravimetric behaviour and fluorescence properties of the title polymer have been investigated.

  16. Experimental exposure of male volunteers to N-methyl-2-pyrrolidone (NMP): acute effects and pharmacokinetics of NMP in plasma and urine.

    PubMed Central

    Akesson, B; Paulsson, K

    1997-01-01

    OBJECTIVES: To study the acute effects of exposure to the increasingly used solvent, N-methyl-2-pyrrolidone (NMP) in male volunteers. Further, to determine the NMP concentration in plasma and urine during and after the exposure. METHODS: Six male volunteers were exposed for eight hours on four different days to 0, 10, 25, and 50 mg/m3 NMP. Plasma was collected and urine was sampled during and after the exposure. Changes in nasal volume were measured by acoustic rhinometry and in airway resistance by spirometry. RESULTS: The eight-hour experimental exposure to 10, 25, and 50 mg/m3 did not induce discomfort to eyes or upper airways. Acute changes in nasal volume were not found, and no changes in the spirometric data could be registered. The elimination curves suggested a non-linear pattern and at the end of exposure showed mean (range) half lifes of NMP in plasma of about 4.0 (2.9-5.8) hours and in urine 4.5 (3.5-6.6) hours. The unmetabolised NMP found in urine samples collected during exposure and at the subsequent 44 hours corresponded to about 2% of the calculated absorbed dose. At the end of the exposure there was a close correlation between exposures and the plasma concentration and urinary excretion of NMP. CONCLUSIONS: NMP was absorbed through the respiratory tract and readily eliminated from the body, mainly by biotransformation to other compounds. Exposure to 10, 25, or 50 mg/m3 NMP did not cause nose, eye, or airway irritation. Thus, NMP is a mild irritant. PMID:9166128

  17. Experimental (X-ray, FT-IR and UV-vis spectra) and theoretical methods (DFT study) of (E)-3-methoxy-2-[(p-tolylimino)methyl]phenol.

    PubMed

    Demircioğlu, Zeynep; Albayrak, Çiğdem; Büyükgüngör, Orhan

    2014-07-15

    A suitable single crystal of (E)-3-methoxy-2-[(p-tolylimino)methyl]phenol, formulated as C15H15N1O2, reveals that the structure is adopted to its E configuration about the azomethine C=N double bond. The compound adopts a enol-imine tautomeric form with a strong intramolecular O-H⋯N hydrogen bond. The single crystal X-ray diffraction analysis at 296K crystallizes in the monoclinic space group P21/c with a = 13.4791(11) Å, b = 6.8251(3) Å, c = 18.3561(15) Å, α = 90°, β = 129.296(5)°, γ = 90° and Z = 4. Comprehensive theoretical and experimental structural studies on the molecule have been carried out by FT-IR and UV-vis spectrometry. Optimized molecular structure and harmonic vibrational frequencies have been investigated by DFT/B3LYP method with 6-31G(d,p) basis set. Stability of the molecule, hyperconjugative interactions, charge delocalization and intramolecular hydrogen bond has been analyzed by using natural bond orbital (NBO) analysis. Electronic structures were discussed by TD-DFT method and the relocation of the electron density were determined. The energetic behavior of the title compound has been examined in solvent media using polarizable continuum model (PCM). Molecular electrostatic potential (MEP), Mulliken population method and natural population analysis (NPA) have been studied. Nonlinear optical (NLO) properties were also investigated. In addition, frontier molecular orbitals analysis have been performed from the optimized geometry. An ionization potential (I), electron affinity (A), electrophilicity index (ω), chemical potential (μ), electronegativity (χ), hardness (η), and softness (S), have been investigated.

  18. Modeling powder encapsulation in dosator-based machines: II. Experimental evaluation.

    PubMed

    Khawam, Ammar; Schultz, Leon

    2011-12-15

    A theoretical model was previously derived to predict powder encapsulation in dosator-based machines. The theoretical basis of the model was discussed earlier. In this part; the model was evaluated experimentally using two powder formulations with substantially different flow behavior. Encapsulation experiments were performed using a Zanasi encapsulation machine under two sets of experimental conditions. Model predicted outcomes such as encapsulation fill weight and plug height were compared to those experimentally obtained. Results showed a high correlation between predicted and actual outcomes demonstrating the model's success in predicting the encapsulation of both formulations. The model is a potentially useful in silico analysis tool that can be used for capsule dosage form development in accordance to quality by design (QbD) principles.

  19. 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

    2011-09-07

    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

  20. Distribution of sac pressure in an experimental aneurysm model after endovascular repair: the effect of endoleak types I and II.

    PubMed

    Xenos, Eleftherios S; Stevens, Scott L; Freeman, Michael B; Pacanowski, John P; Cassada, David C; Goldman, Mitchell H

    2003-06-01

    To study in an experimental aneurysm model the differential distribution of strain/pressure (S/P) on the aneurysm wall before and after endograft exclusion and in the presence of individual type I and type II endoleaks. Two tapered elliptical Gore-Tex patches were sutured to an anterior and posterior longitudinal arteriotomy of an 8-mm Gore-Tex tube graft, thus creating a fusiform aneurysm. Two S/P transducers were placed at the proximal sac adjacent to the proximal neck, 2 at the site of the widest sac diameter, and 2 at the sac adjacent to the distal neck. The aneurysm, which was connected to a pulsatile pump system, was excluded using a 10-mm endograft. Type I and type II endoleaks were created and tested individually. S/P measurements were obtained at systemic systolic pressures (BP) of 80, 110, and 150 mmHg. Thrombosis of the sac contents was induced by injection of thrombin and calcium in the sac. Angiography was used to verify presence or absence of flow in the sac. Aneurysm exclusion resulted in significant S/P reductions at all 3 BP levels versus prior to exclusion (p<0.05). Thrombus in the sac did not alter S/P in the excluded sac (p>0.05 for all 3 BP levels). In the presence of a proximal type I endoleak, S/P distribution was not uniform, and S/P at the proximal neck was close to S/P prior to exclusion (p>0.05 no graft versus type I endoleak for all 3 BP levels). This was also true in the presence of thrombus. With a type II endoleak, S/P was more evenly distributed and was not significantly elevated compared to the pressure without an endoleak (p>0.05, graft versus type II endoleak for all 3 BP levels). Thrombus had no effect on intrasac S/P with a type II endoleak. Intrasac S/P was significantly higher in the presence of a type I endoleak compared to a type II endoleak when BP=150 mmHg (p=0.008). Endovascular exclusion of an aneurysm results in uniform S/P reduction in the aneurysm sac. Type I endoleak, but not type II endoleak, results in

  1. Experimental Investigation on the Mechanism of Chelation-Assisted, Copper(II) Acetate-Accelerated Azide-Alkyne Cycloaddition

    PubMed Central

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

    2011-01-01

    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 1H NMR assays are developed for monitoring the reaction progress in two different solvents – methanol and acetonitrile. Solvent kinetic isotopic effect and pre-mixing 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

  2. 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.

  3. 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

  4. Theoretical and Experimental Investigations of (I) Reaction Kinetics. (II) Theory of Liquids, and (III) Optical Rotation

    DTIC Science & Technology

    1975-02-14

    The "region of indifference" to a phase change with pressure in camphor has been found to decrease markedly with purification. Mini (continued on...for High Pressure Transitions in d- Camphor (TI-III) and Phosphorus (I-II)", by A. F. Gabrysh, A. Vanhook and H. Eyring, J. Phys. Chem. Solids, 25, 129...on the transformation in d- camphor and phosphorus. The so-called "region of ind;ffer’e,-e" rennrted as approximately .38 kilobars in phosphorus, was

  5. 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

  6. 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…

  7. 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…

  8. Parametric and non-parametric modeling of short-term synaptic plasticity. Part II: Experimental study.

    PubMed

    Song, Dong; Wang, Zhuo; Marmarelis, Vasilis Z; Berger, Theodore W

    2009-02-01

    This paper presents a synergistic parametric and non-parametric modeling study of short-term plasticity (STP) in the Schaffer collateral to hippocampal CA1 pyramidal neuron (SC) synapse. Parametric models in the form of sets of differential and algebraic equations have been proposed on the basis of the current understanding of biological mechanisms active within the system. Non-parametric Poisson-Volterra models are obtained herein from broadband experimental input-output data. The non-parametric model is shown to provide better prediction of the experimental output than a parametric model with a single set of facilitation/depression (FD) process. The parametric model is then validated in terms of its input-output transformational properties using the non-parametric model since the latter constitutes a canonical and more complete representation of the synaptic nonlinear dynamics. Furthermore, discrepancies between the experimentally-derived non-parametric model and the equivalent non-parametric model of the parametric model suggest the presence of multiple FD processes in the SC synapses. Inclusion of an additional set of FD process in the parametric model makes it replicate better the characteristics of the experimentally-derived non-parametric model. This improved parametric model in turn provides the requisite biological interpretability that the non-parametric model lacks.

  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. 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. © 2015 Wiley Periodicals, Inc.

  11. Bis(2-amino-6-methyl­pyrimidin-1-ium-4-olate-κ2 N 3,O)bis­(nitrato-κ2 O,O′)cadmium(II)

    PubMed Central

    Kaabi, Kamel; El Glaoui, Meher; Pereira Silva, P. S.; Ramos Silva, M.; Ben Nasr, Cherif

    2010-01-01

    In the title compound, [Cd(NO3)2(C5H7N3O)2], the CdII atom is eight-coordinated by two amine N atoms and two O atoms from two zwitterionic, biodentate 2-amino-6-methyl­pyrimidin-1-ium-4-olate ligands and by four O atoms from two nitrate groups. Intra­molecular N—H⋯O hydrogen bonds occur. The crystal packing is stabilized by inter­molecular N—H⋯O and C—H⋯O hydrogen bonds, two of which are bifurcated, between the nitrate anions and the organic groups. PMID:21579276

  12. 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

  13. 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

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

    2015-01-01

    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.

  14. 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.

  15. Thiocyanate-free cyclometalated ruthenium(II) sensitizers for DSSC: a combined experimental and theoretical investigation.

    PubMed

    Chitumalla, Ramesh Kumar; Gupta, Kankatala S V; Malapaka, Chandrasekhram; Fallahpour, Reza; Islam, Ashraful; Han, Liyuan; Kotamarthi, Bhanuprakash; Singh, Surya Prakash

    2014-02-14

    In an effort to bring out efficient thiocyanate-free dyes for dye sensitized solar cells (DSSC) we have designed, synthesized and characterized four novel cyclometalated ruthenium(II) dyes (M1 to M4) with superior photochemical properties. All dyes contain terpyridyl ligands (TPY) with carboxylic acids as anchoring groups and cyclometalated ligand (TPY-C) with substituents for fine tuning the electronic properties. We obtain a broad absorption band which extends up to 725 nm due to metal to ligand charge transfer (MLCT) when donating groups are used, which slightly blue-shifts when a withdrawing group is used. In addition to the CT, small HOMO-LUMO gaps are obtained from electrochemical measurements which indicate characteristics of an ideal sensitizer. All four dyes were used as sensitizers for DSSC and photoelectrochemical measurements were carried out. Reasonably good efficiency (7.1%) has been achieved for . We have carried out periodic-DFT studies of these dyes adsorbed on the (TiO2)38 cluster. They revealed that, in bidentate bridging mode the dyes preferably bind with the help of two carboxylic groups onto the TiO2. To the best of our knowledge we are the first to do DFT studies of thiocyanate free cyclometalated ruthenium(ii) dyes tethered to TiO2.

  16. Methyl methacrylate

    Integrated Risk Information System (IRIS)

    TOXICOLOGICAL REVIEW of METHYL METHACRYLATE ( CAS No . 80 - 62 - 6 ) In Support of Summary Information on the Integrated Risk Information System ( IRIS ) January 1998 U.S . Environmental Protection Agency Washington , DC TABLE OF CONTENTS DISCLAIMER . . . . . . . . . . . . . . . . . . . . . . . . .

  17. CG methylation.

    PubMed

    Vinson, Charles; Chatterjee, Raghunath

    2012-12-01

    A striking feature of mammalian genomes is the paucity of the CG dinucleotide. There are approximately 20,000 regions termed CpG islands where CGs cluster. This represents 5% of all CGs and 1% of the genome. CpG islands are typically unmethylated and are often promoters for housekeeping genes. The remaining 95% of CG dinucleotides are disposed throughout 99% of the genome and are typically methylated and found in half of all promoters. CG methylation facilitates binding of the C/EBP family of transcription factors, proteins critical for differentiation of many tissues. This allows these proteins to localize in the methylated CG poor regions of the genome where they may produce advantageous changes in gene expression at nearby or more distant regions of the genome. In this review, our growing understanding of the consequences of CG methylation will be surveyed.

  18. 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.

  19. Characterization of a Three-Dimensional Turret Wake for Active Flow Control Part II: Experimental Study

    NASA Astrophysics Data System (ADS)

    Shea, Patrick; Ruscher, Christopher; Wallace, Ryan; Glauser, Mark; Dannenhoffer, John, III

    2010-11-01

    Experimental measurements have been performed to characterize the wake of a three-dimensional, non-conformal turret. Experiments were performed in a low-speed wind tunnel at Syracuse University using particle image velocimetry, hotwire anemometry and dynamic and static pressure measurements. The objective of the study was to characterize the spatial and temporal nature of the wake region as well as to investigate the importance of the incoming flow field. Computational studies have been performed in conjunction with this work to help guide the experimental study and offer insight into the complex three-dimensional flow field. With a better understanding of the wake and three-dimensional characteristics of the turret flow field, closed-loop, active flow control systems will be developed to help reduce fluctuating loading and aero-optical distortions associated with the turbulent flow field.

  20. Experimental violation of a Bell-Leggett-Garg inequality using weak measurements, Part II: The Violation

    NASA Astrophysics Data System (ADS)

    White, T. C.; Mutus, J.; Dressel, J.; Kelly, J.; Barends, R.; Megrant, A.; Jeffrey, E.; Sank, D.; Campbell, B.; Chen, Y.; Chen, Z.; Chiaro, B.; Dunsworth, A.; Fowler, A.; Hoi, I.-C.; Neill, C.; O'Malley, P. J. J.; Roushan, P.; Quintana, C.; Vainsencher, A.; Wenner, J.; Korotkov, A. N.; Cleland, A. N.; Martinis, J. M.

    2015-03-01

    We experimentally demonstrate the violation of a hybrid Bell-Leggett-Garg inequality that avoids both the disjoint sampling and fair sampling loopholes that are common to traditional Bell inequalities. Our algorithm uses sequential weak measurements of a Bell state that are implemented with four superconducting Xmon qubits. In this second of two talks, we present experimental detail on the measurement of the CHSH correlator and the analysis of error mechanisms. We find that the dependence of the correlations on the measurement strength shows excellent agreement with theoretical predictions, but the magnitude of the correlator varies greatly with system fidelity. For sufficiently weak and high fidelity measurements, we achieve a violation that is many standard deviations above the classical limit.

  1. The User-Assisted Automated Experimental (TEST) Design Program (AED): Version II.

    DTIC Science & Technology

    1983-01-01

    ADDRESS 10. PROGRAM ELEMENT. PROJECT. TASK System Development Corporation AREA & WORK UNIT NUMBERS 4134 Linden Avenue Suite 305 62202F, 7184-00-09...pro- cedures and which maximize information return while minimizing the number of observations (tests) required. The overall experimental design...E. Taylor, SDC Colorado Springs, CO, for his work on the Central Composite Design, Mr. Edwin G. Meyer who developed many of the algorithms and

  2. 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.

  3. 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.

  4. STUDIES ON THE ETIOLOGY OF RABBIT POX : II. CLINICAL CHARACTERISTICS OF THE EXPERIMENTALLY INDUCED DISEASE.

    PubMed

    Rosahn, P D; Hu, C K; Pearce, L

    1936-01-31

    The clinical manifestations and course of disease observed in experimental rabbit pox have been described and analyzed. The condition differed from the acute fulminating and rapidly fatal type of experimental infection (1) in that the period of survival was longer, a variety of clinical manifestations developed and a considerable proportion of the cases recovered. The most conspicuous symptom was a generalized papular eruption on the skin and mucocutaneous borders. The production of the disease was associated with routes of inoculation other than the intratesticular or with a small dosage. The majority of cases were inoculated with Berkefeld V filtrates of tissue-virus emulsions and not with the more potent unfiltered emulsions. The local reactions resulting from various routes of inoculation were described. Of special interest were the pronounced cutaneous reactions induced by intradermal injection, the high instance of marked clinical manifestations after intravenous inoculation, the failure of lesions to localize in the lines of scarification of skin and cornea even in cases with a profuse cutaneous eruption, and the development of cytoplasmic inclusion bodies in the epithelial cells of the cornea following scarification and conjunctival instillation of virus. In the character of its clinical manifestations and course of disease, experimental rabbit pox was indistinguishable from cases of the spontaneous pox.

  5. Dissolution of particles in binary alloys: part II. experimental investigation on an Al-Si alloy

    NASA Astrophysics Data System (ADS)

    Tundal, Ulf H.; Ryum, Nils

    1992-02-01

    A detailed experimental study of the dissolution kinetics of Si particles in an Al-Si alloy has been carried out in order to test the validity of the two models presented in the accompanying article.[1] In these models, the dissolution kinetics are dependent on the particle size distribution of the alloy. An alloy with composition Co = 0.77 at. pct Si was heat-treated in order to obtain rather coarse spherical particles (1 to 10 μn). The size distribution of the particles was found to be close to the log-normal distribution. At high temperatures, when the solvus concentration was well above Co, the experimental values were very close to the values of the model which predicted the highest dissolution rates. At lower temperatures, when the solvus concentration was closer to C o, the experimental values lay in between the values predicted by the two models. The results clearly demonstrate that a size distribution of particles must be included in the model if an accurate prediction of the dissolution kinetics is to be achieved.

  6. Determination of competitive adsorption isotherms applying the nonlinear frequency response method. Part II. Experimental demonstration.

    PubMed

    Ilić, Milica; Petkovska, Menka; Seidel-Morgenstern, Andreas

    2009-08-14

    This paper demonstrates an experimental application of the nonlinear frequency response (FR) method extension to determine adsorption isotherms of binary mixtures. This method, based on the analysis of the response of a chromatographic column subjected to the sinusoidal inlet concentration changes, is shown to be an alternative for isotherm determination. The critical issue related to the successful application of the method is to reach experimentally the low frequency asymptotic behaviour of the corresponding frequency response functions (FRFs). Although, there are different possibilities to perform periodical inlet concentration changes, in this paper only simultaneous changes for both components were considered. The adsorption of phenol and 2-phenylethanol on octadecyl silica was analyzed experimentally using a mixture of methanol and water as a solvent. Parameters of competitive isotherms were also estimated for comparison using the classical perturbation method. Despite certain differences between competitive isotherms estimated with the two methods that were found, the obtained results show the potential of the nonlinear FR method for measuring competitive isotherms.

  7. 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

  8. Exposure to 3,3',5-triiodothyronine affects histone and RNA polymerase II modifications, but not DNA methylation status, in the regulatory region of the Xenopus laevis thyroid hormone receptor βΑ gene.

    PubMed

    Kasai, Kentaro; Nishiyama, Norihito; Izumi, Yushi; Otsuka, Shunsuke; Ishihara, Akinori; Yamauchi, Kiyoshi

    2015-11-06

    Thyroid hormones (THs) play a critical role in amphibian metamorphosis, during which the TH receptor (TR) gene, thrb, is upregulated in a tissue-specific manner. The Xenopus laevis thrb gene has 3 TH response elements (TREs) in the 5' flanking regulatory region and 1 TRE in the exon b region, around which CpG sites are highly distributed. To clarify whether exposure to 3,3',5-triiodothyronine (T3) affects histone and RNA polymerase II (RNAPII) modifications and the level of DNA methylation in the 5' regulatory region, we conducted reverse transcription-quantitative polymerase chain reaction, bisulfite sequencing and chromatin immunoprecipitation assay using X. laevis cultured cells and premetamorphic tadpoles treated with or without 2 nM T3. Exposure to T3 increased the amount of the thrb transcript, in parallel with enhanced histone H4 acetylation and RNAPII recruitment, and probably phosphorylation of RNAPII at serine 5, in the 5' regulatory and exon b regions. However, the 5' regulatory region remained hypermethylated even with exposure to T3, and there was no significant difference in the methylation status between DNAs from T3-untreated and -treated cultured cells or tadpole tissues. Our results demonstrate that exposure to T3 induced euchromatin-associated epigenetic marks by enhancing histone acetylation and RNAPII recruitment, but not by decreasing the level of DNA methylation, in the 5' regulatory region of the X. laevis thrb gene.

  9. 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

  10. 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

  11. Analysis of copy-number variation, insertional polymorphism, and methylation status of the tiniest class I (TRIM) and class II (MITE) transposable element families in various rice strains.

    PubMed

    Baruch, Omer; Kashkush, Khalil

    2012-05-01

    Transposable elements (TEs) dominate the genetic capacity of most eukaryotes, especially plants, where they may compose up to 90% of the genome. Many studies, both in plants and animals reported that in fact non-autonomous elements that have lost their protein-coding sequences and became miniature elements were highly associated with genes, and showed a high level of transpositional activity such as mPing family in rice. In this study, we have investigated in detail the copy number, insertional polymorphism and the methylation status of the tiniest LTR retrotransposon family, termed TRIM, in nine rice strains, in comparison with mPing. While TRIM showed similar copy numbers (average of 79 insertions) in all the nine rice strains, the copy number of mPing varied dramatically (ranging from 6 to 203 insertions) in the same strains. Site-specific PCR analysis revealed that ~58% of the TRIM elements have identical insertion sites among the nine rice strains, while none of the mPing elements (100% polymorphism) have identical insertion sites in the same strains. Finally, over 65% of the TRIM insertion sites were cytosine methylated in all nine rice strains, while the level of the methylated mPing insertion sites ranged between 43 and 81.5%. The findings of this study indicate that unlike mPing, TRIM is most probably a fossil TE family in rice. In addition, the data shows that there might be a strong correlation between TE methylation and copy number.

  12. 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.

  13. Saturation of Energy Levels in Analytical Atomic Fluorescence Spectrometry. II. Experimental.

    DTIC Science & Technology

    1981-01-30

    REPORT NUNSER01 I.Experimentald 7. TTH.ORi. - I.- . CONTROACT On GRANT NSIER(s) Dorys Rojas deOlivares aW Gary M./Hieftje / N14-76-C-0838 CIS. PERFORMING...EXPERIMENTAL by Dorys Rojas de Olivares and Gary M. Hieftje Prepared for Publication Accession For WTIS GRA&I in DTIC TAB Unannozincod F...necessary. ACKNOWLEDGEMlENT wrVVwVVA VVVV\\IVV I Taken in part from the Ph.D. thesis of D. Rojas de Olivares, Indiana University, 1976. Supported in part

  14. 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.

  15. Experimental hypervelocity impact into quartz sand. II - Effects of gravitational acceleration

    NASA Technical Reports Server (NTRS)

    Gault, D. E.; Wedekind, J. A.

    1977-01-01

    Experimental results for craters formed by aluminum spheres impacting at normal incidence against quartz sand targets in gravitational acceleration environments ranging from 0.073 to 1.0 g (g = 980 cm/sq sec) are reported. Impact velocities varied from 0.4 to 8.0 km/sec. Crater dimensions and formation times are compared with results from a simplified dimensional analysis of the cratering processes. Although the comparison indicates a dominant role of gravity relative to the target strength for craters formed in sand, the results serve primarily to emphasize that both gravity and strength are variables of fundamental significance to cratering processes.

  16. Experimentally tractable, pseudo-elastic constitutive law for biomembranes: II. Application.

    PubMed

    Criscione, John C; Sacks, Michael S; Hunter, William C

    2003-02-01

    This is the second paper of a 2 part series. In the first, a theoretical framework is developed that provides 3 enhancements for the constitutive theory of biomembranes. 1) Covariance amongst response terms is minimized, 2) the pseudo-strain-energy potential is redefined so as to be measurable, and 3) the stress response is decomposed into 2 parts--a hyperelastic part plus a hypoelastic-stress-residual. This paper illustrates the experimental advantages of this novel constitutive theory via analysis of biaxial test data obtained from chemically treated bovine pericardium.

  17. Cell growth and division. II. Experimental studies of cell volume distributions in mammalian suspension cultures.

    PubMed

    Anderson, E C; Petersen, D F

    1967-07-01

    Experimental proof is given that the volume distribution spectrum of mammalian cells in suspension culture can be determined accurately with a Coulter spectrometer. Stable spectra corresponding to the predictions of a mathematical model are observed under favorable conditions of growth. Cell volume spectrometry appears to be a useful method for diagnosing the state of the culture with respect to past uniformity of growth rate and present population age distribution. In addition, it offers a method for quantitative study of the laws governing cell growth and division.

  18. Palladium(II) and platinum(II) organometallic complexes with 4,7-dihydro-5-methyl-7-oxo[1,2,4]triazolo[1,5-a]pyrimidine. Antitumor activity of the platinum compounds.

    PubMed

    Ruiz, José; Villa, María Dolores; Cutillas, Natalia; López, Gregorio; de Haro, Concepción; Bautista, Delia; Moreno, Virtudes; Valencia, Laura

    2008-06-02

    Palladium and platinum complexes with HmtpO (where HmtpO=4,7-dihydro-5-methyl-7-oxo[1,2,4]triazolo[1,5-a]pyrimidine, an analogue of the natural occurring nucleobase hypoxanthine) of the types [M(dmba)(PPh3)(HmtpO)]ClO4[dmba=N,C-chelating 2-(dimethylaminomethyl)phenyl; M=Pd or Pt], [Pd(N-N)(C6F5)(HmtpO)]ClO4[N-N=2,2'-bipyridine (bpy), 4,4'-dimethyl-2,2'-bipyridine (Me2bpy), or N, N, N', N'-tetramethylethylenediamine (tmeda)] and cis-[M(C6F5)2(HmtpO)2] (M=Pd or Pt) (head-to-head atropisomer in the solid state) have been obtained. Pd(II) and Pt(II) complexes with the anion of HmtpO of the types [Pd(tmeda)(C6F5)(mtpO)], [Pd(dmba)(micro-mtpO)] 2, and [NBu4]2[M(C6F5)2(micro-mtpO)]2(M=Pd or Pt) have been prepared starting from the corresponding hydroxometal complexes. Complexes containing simultaneously both the neutral HmtpO ligand and the anionic mtpO of the type [NBu4][M(C6F5)2(HmtpO)(mtpO)] (M=Pd or Pt) have been also obtained. In these mtpO-HmtpO metal complexes, for the first time, prototropic exchange is observed between the two heterocyclic ligands. The crystal structures of [Pd(dmba)(PPh 3)(HmtpO)]+, cis-[Pt(C6F5)2(HmtpO)2].acetone, [Pd(C6F5)(tmeda)(mtpO)].2H2O, [Pd(dmba)(micro-mtpO)]2, [NBu4]2[Pd(C6F5)2(micro-mtpO)]2.CH2Cl2.toluene, [NBu4]2[Pt(C6F5)2(micro-mtpO)](2).0.5(toluene), and [NBu4][Pt(C6F5)2(mtpO)(HmtpO)] have been established by X-ray diffraction. Values of IC50 were calculated for the new platinum complexes cis-[Pt(C6F5)2(HmtpO)2] and [Pt(dmba)(PPh3)(HmtpO)]ClO4 against a panel of human tumor cell lines representative of ovarian (A2780 and A2780 cisR), lung (NCI-H460), and breast cancers (T47D). At 48 h incubation time, both complexes were about 8-fold more active than cisplatin in T47D and show very low resistance factors against an A2780 cell line, which has acquired resistance to cisplatin. The DNA adduct formation of cis-[Pt(C6F5)2(HmtpO)2] and [Pt(dmba)(PPh3)(HmtpO)]ClO4 was followed by circular dichroism and electrophoretic mobility. Atomic

  19. 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.

  20. Influence of a stationary magnetic field on water relations in lettuce seeds. Part II: experimental results.

    PubMed

    Reina, F G; Pascual, L A; Fundora, I A

    2001-12-01

    An experimental study on water absorption by lettuce seeds previously treated in a stationary magnetic field of 0-10 mT is presented. A significant increase in the rate with which the seeds absorb water is observed in the interval 0-10 mT of magnetic treatment. An increment in the total mass of absorbed water in this interval is also observed. These results are consistent with the reports on the increase of germination rate of the seeds, and the theoretical calculation of the variations induced by magnetic fields in the ionic currents across the cellular membrane. The fields originate in changes in the ionic concentration and thus in the osmotic pressure which regulates the entrance of water to the seeds. The good correlation between the theoretical approach and experimental results provides strong evidence that the magnetic field alters the water relations in seeds, and this effect may be the explanation of the reported alterations in germination rate of seeds by the magnetic field.

  1. Integration of Error Compensation of Coordinate Measuring Machines into Feature Measurement: Part II-Experimental Implementation.

    PubMed

    Calvo, Roque; D'Amato, Roberto; Gómez, Emilio; Domingo, Rosario

    2016-10-14

    Coordinate measuring machines (CMM) are main instruments of measurement in laboratories and in industrial quality control. A compensation error model has been formulated (Part I). It integrates error and uncertainty in the feature measurement model. Experimental implementation for the verification of this model is carried out based on the direct testing on a moving bridge CMM. The regression results by axis are quantified and compared to CMM indication with respect to the assigned values of the measurand. Next, testing of selected measurements of length, flatness, dihedral angle, and roundness features are accomplished. The measurement of calibrated gauge blocks for length or angle, flatness verification of the CMM granite table and roundness of a precision glass hemisphere are presented under a setup of repeatability conditions. The results are analysed and compared with alternative methods of estimation. The overall performance of the model is endorsed through experimental verification, as well as the practical use and the model capability to contribute in the improvement of current standard CMM measuring capabilities.

  2. 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.

  3. [Pharmacological studies of FUT-175, nafamstat mesilate. II. Effects on experimental acute pancreatitis].

    PubMed

    Iwaki, M; Ozeki, M; Sato, T; Suzuki, K; Motoyoshi, A; Suzuki, S; Fujita, M; Aoyama, T

    1984-10-01

    Effects of FUT-175, a novel synthetic protease-inhibiting agent, on various models of experimental acute pancreatitis were examined. FUT-175 infused i.v. at a dose range of 5-50 micrograms/kg/min inhibited the increase in plasma trypsin activity and reduced the mortality of rabbits in trypsin-induced acute pancreatitis in a dose-dependent manner. Increase in serum amylase activity and pancreatic tissue lesion were attenuated in rabbits. In addition, FUT-175 infused i.v. at a dose range of 1-50 micrograms/kg/min reduced the mortality of rats in experimental acute pancreatitis produced by trypsin and endotoxin. FUT-175 infused i.v. at a dose range of 1-100 micrograms/kg/min protected the dogs from the increase in plasma trypsin activity and hypotension and shock induced by trypsin, well-known characteristics of acute pancreatitis. These results suggest that FUT-175 is beneficial as a therapeutic agent of acute pancreatitis.

  4. 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

  5. Crystal structure of di-chlorido-{2-methyl-2-[(pyridin-2-ylmeth-yl)amino]-propan-1-ol-κ(3)N,N',O}copper(II) from synchrotron data.

    PubMed

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

    2016-10-01

    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-ylmeth-yl)amino]-propan-1-ol (mpmapOH) ligand, including pyridine, amine and hy-droxy groups, was synthesized by the reaction of 2-amino-2-methyl-propan-1-ol with pyridine-2-carbaldehyde and was characterized by NMR spectroscopy. In its Cu(II) 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 Cu(II) 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. Inter-molecular hydrogen bonds (N-H⋯Cl and O-H⋯Cl) and face-to-face π-π inter-actions stabilize the mol-ecular structure and give rise to a two-dimensional supra-molecular structure extending parallel to (101).

  6. Serial displacement chromatofocusing and its applications in multidimensional chromatography and gel electrophoresis: II. Experimental results.

    PubMed

    Shen, Hong; Li, Xiang; Bieberich, Charles; Frey, Douglas D

    2009-02-06

    Part I of this study investigated the theory and basic characteristics of "serial displacement chromatofocusing" (SDC). In Part II of this study, SDC is applied to two prototype applications which have potential uses in proteomics and related areas involving the analysis of complex analyte mixtures. In the first application, SDC was used as a prefractionation method prior to two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) to separate a human prostate cancer cell lysate. It was observed that the resolution achieved in narrow-pI-range 2D-PAGE was improved when using SDC prefractionation, so that SDC may be useful as a low-cost, high-speed, and highly scalable alternative to electrophoretic prefractionation methods for 2D-PAGE. The second application involves the use of SDC as the first dimension, and reversed-phase chromatography as the second dimension, to produce a novel, fully automated, two-dimensional high-performance liquid chromatography technique. The method was shown to have performance advantages over one-dimensional reversed-phase chromatography for peptide separations.

  7. Oxidative modification of type II collagen differentially affects its arthritogenic and tolerogenic capacity in experimental arthritis.

    PubMed

    Marcinkiewicz, Janusz; Biedroń, Rafał; Maresz, Katarzyna; Kwaśny-Krochin, Beata; Bobek, Małgorzata; Kontny, Ewa; Maśliński, Wlodzimierz; Chain, Benjamin

    2004-01-01

    Oxidative modification of proteins affects their biological properties. Previously we have shown that hypochlorite (HOCl), the product of activated neutrophils, enhances protein immunogenecity. Collagen type II, a primary component of cartilage, is commonly used in the induction of arthritis in animals (CIA). The aim of this study was to examine whether HOCl may affect immunogenic, tolerogenic, and arthritogenic properties of collagen. DBA/J mice were injected with either native (CNAT) or chlorinated collagen (CHOCl) to induce arthritis. The effect of chlorination on collagen properties was measured by evaluation of incidence and severity of CIA. Moreover, the concentration of serum anti-collagen IgG antibodies and myeloperoxidase (MPO) activity in inflamed joints was determined. Mice immunized with CNAT in adjuvant developed arthritis (CIA) with an incidence of 69%. CNAT also exerted tolerogenic properties when injected intravenously either before or shortly after primary immunization, resulting in decreased incidence and severity of CIA, reduced MPO activity in inflamed joints, and lowered serum levels of anti-CNAT IgG anti-bodies. Chlorination of collagen significantly diminished its ability to induce CIA and to trigger generation of anti-CNAT IgG antibodies. Interestingly, chlorination did not affect tolerogenic properties of collagen administered prior to primary immunization with CNAT. These results suggest that chlorination of collagen may selectively affect functional epitopes of collagen. It is likely that in inflamed joints, neutrophil derived HOCl, in some circumstances, will destroy arthritogenic and immunogenic B cell epitopes, while regulatory T cell epitopes will be preserved.

  8. Experimental and theoretical studies of Diels-Alder reaction between methyl (Z)-2-nitro-3-(4-nitrophenyl)-2-propenoate and cyclopentadiene.

    PubMed

    Jasiński, Radomir; Kwiatkowska, Magdalena; Sharnin, Valentin; Barański, Andrzej

    The Diels-Alder reaction between methyl (Z)-2-nitro-3-(4-nitrophenyl)-2-propenoate and cyclopentadiene yields a mixture of carbodiene Diels-Alder adducts. B3LYP/6-31G(d) simulations indicate that the conversion of addends into methyl (1R*,2S*,3S*,4R*)-2-nitro-3-(4-nitrophenyl)-bicyclo[2.2.1]hept-5-ene-2-carboxylate occurs via two-stage heterodiene Diels-Alder reaction and (in a second step) skeleton rearrangement of the primary cycloadduct, whereas the reaction leading to methyl (1R*,2R*,3R*,4R*)-2-nitro-3-(4-nitrophenyl)-bicyclo[2.2.1]hept-5-ene-2-carboxylate is a single-step process.

  9. Transgene-induced CCWGG methylation does not alter CG methylation patterning in human kidney cells.

    PubMed

    Shevchuk, Taras; Kretzner, Leo; Munson, Kristofer; Axume, John; Clark, Jarrod; Dyachenko, Olga V; Caudill, Marie; Buryanov, Yaroslav; Smith, Steven S

    2005-01-01

    Several reports suggest that C(m)CWGG methylation tends not to co-exist with (m)CG methylation in human cells. We have asked whether or not methylation at CCWGG sites can influence CG methylation. DNA from cells expressing an M.EcoRII-GFP fusion was actively methylated at CCWGG sites. CG methylation as measured by R.HpaII/R.MspI ratios was unchanged in cells expressing the transgene. Cloned representatives of C(m)CWGG methylated DNA often contained, or were adjacent to an ALU repeat, suggesting that M.EcoRII-GFP actively methylated gene-rich R-band DNA. The transgenic methyltransferase applied C(m)CWGG methylation to a representative human promoter that was heavily methylated at CG dinucleotides (the SERPINB5 promoter) and to a representative promoter that was essentially unmethylated at CG dinucleotides (the APC promoter). In each case, the CG methylation pattern remained in its original state, unchanged by the presence of neighboring C(m)CWGG sites. Q-PCR measurements showed that RNA expression from the APC gene was not significantly altered by the presence of C(m)CWGG in its promoter. Kinetic studies suggested that an adjacent C(m)CWGG methylation site influences neither the maintenance nor the de novo methylation activities of purified human Dnmt1. We conclude that C(m)CWGG methylation does not exert a significant effect on CG methylation in human kidney cells.

  10. 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 temperatures at least

  11. Experimental murine myopia induces collagen type Iα1 (COL1A1) DNA methylation and altered COL1A1 messenger RNA expression in sclera

    PubMed Central

    Zhou, Xiangtian; Ji, Fengtao; An, Jianhong; Zhao, Fuxin; Shi, Fanjun; Huang, Furong; Li, Yuan; Jiao, Shiming; Yan, Dongsheng; Chen, Xiaoyan; Chen, JiangFan

    2012-01-01

    Purpose To investigate whether myopia development is associated with changes of scleral DNA methylation in cytosine-phosphate-guanine (CpG) sites in the collagen 1A1 (COL1A1) promoter and messenger RNA (mRNA) levels following murine form deprivation myopia. Methods Fifty-seven C57BL/6 mice (postnatal day 23) were randomly assigned to four groups: (1) monocular form deprivation (MD) in which a diffuser lens was placed over one eye for 28 days; (2) normal controls without MD; (3) MD recovery in which the diffuser lens was removed for seven days; and (4) MD recovery normal controls. The DNA methylation pattern in COL1A1 promoter and exon 1 was determined by bisulfite DNA sequencing, and the COL1A1 mRNA level in sclera was determined by quantitative PCR. Results MD was found to induce myopia in the treated eyes. Six CpG sites in the promoter and exon 1 region of COL1A1 were methylated with significantly higher frequency in the treated eyes than normal control eyes (p<0.05), with CpG island methylation in MD-contralateral eyes being intermediate. Consistent with the CpG methylation, scleral COL1A1 mRNA was reduced by 57% in the MD-treated eyes compared to normal controls (p<0.05). After seven days of MD recovery, CpG methylation was significantly reduced (p=0.01). The methylation patterns returned to near normal level in five CpG sites, but the sixth was hypomethylated compared to normal controls. Conclusions In parallel with the development of myopia and the reduced COL1A1 mRNA, the frequency of methylation in CpG sites of the COL1A1 promoter/exon 1 increased during MD and returned to near normal during recovery. Thus, hypermethylation of CpG sites in the promoter/exon 1 of COL1A1 may underlie reduced collagen synthesis at the transcriptional level in myopic scleras. PMID:22690110

  12. Frequency response testing at Experimental Breeder Reactor II using discrete-level periodic signals

    SciTech Connect

    Rhodes, W.D.; Larson, H.A. . Coll. of Engineering); Dean, E.M. )

    1990-01-01

    The Experimental Breeder Reactor 2 (EBR-2) reactivity-to-power frequency-response function was measured with pseudo-random, discrete-level, periodic signals. The reactor power deviation was small with insignificant perturbation of normal operation and in-place irradiation experiments. Comparison of results with measured rod oscillator data and with theoretical predictions show good agreement. Moreover, measures of input signal quality (autocorrelation function and energy spectra) confirm the ability to enable this type of frequency response determination at EBR-2. Measurements were made with the pseudo-random binary sequence, quadratic residue binary sequence, pseudo-random ternary sequence, and the multifrequency binary sequence. 10 refs., 7 figs., 3 tabs.

  13. Experimental polyurethane foam roof systems - II. Technical note Oct 75-Jul 81

    SciTech Connect

    Alumbaugh, R.L.; Keeton, J.R.; Humm, E.F.

    1983-01-01

    An experimental roofing installation is described in which polyurethane foam (PUF) was spray-applied directly to metal Butlerib-type metal decks, the roof divided into five approximately equal areas, and the PUF protected with five different elastomeric coating systems. Three of the coating systems were damaged by hailstones about a year after installation; these systems were recoated within 3 years of the initial installation. The current coatings include two of the original coating systems - a plural component silicone and a single component silicone - and those applied over the three systems damaged by hail - a single component silicone, an aluminum filled, hydrocarbon-extended catalyzed urethane, and a catalyzed urethane. The performance of these five PUF systems over a 7-year period is reported. The temperature distributions throughout the roof systems are described. The decay in the thermal conductivity of the PUF roof over a 5-year period is presented, and the energy savings realized by foaming the roof are presented.

  14. Implementation of multivariable control techniques with application to Experimental Breeder Reactor II

    SciTech Connect

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

    1990-06-01

    After several successful applications to aerospace industry, the modern control theory methods have recently attracted many control engineers from other engineering disciplines. For advanced nuclear reactors, the modern control theory may provide major advantages in safety, availability, and economic aspects. This report is intended to illustrate the feasibility of applying the linear quadratic Gaussian (LQG) compensator in nuclear reactor applications. The LQG design is compared with the existing classical control schemes. Both approaches are tested using the Experimental Breeder Reactor 2 (EBR-2) as the system. The experiments are performed using a mathematical model of the EBR-2 plant. Despite the fact that the controller and plant models do not include all known physical constraints, the results are encouraging. This preliminary study provides an informative, introductory picture for future considerations of using modern control theory methods in nuclear industry. 10 refs., 25 figs.

  15. 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.

  16. The structure of small, vapor-deposited particles. II - Experimental study of particles with hexagonal profile

    NASA Technical Reports Server (NTRS)

    Yacaman, M. J.; Heinemann, K.; Yang, C. Y.; Poppa, H.

    1979-01-01

    'Multiply-twinned' gold particles with hexagonal bright field TEM profile were determined to be icosahedra composed of 20 identical and twin-related tetrahedral building units that do not have an fcc structure. The crystal structure of these slightly deformed tetrahedra is rhombohedral. Experimental evidence supporting this particle model was obtained by selected-zone dark field and weak beam dark field electron microscopy. In conjunction with the results of part I, it has been concluded that multiply-twinned gold particles of pentagonal or hexagonal profile that are found during the early stages of the vapor deposition growth process on alkali halide surfaces do not have an fcc crystal structure, which is in obvious contrast to the structure of bulk gold.

  17. Melting of oxidized nickel ores in a barbotage unit: II. Experimental investigations

    NASA Astrophysics Data System (ADS)

    Starykh, R. V.; Pakhomov, R. A.

    2016-07-01

    The possibility of efficient processing of oxidized nickel ores (ONOs) to form ferronickel in a barbotage unit (liquid bath melting (LBM), Vanyukov furnace) is corroborated theoretically and experimentally. The processing of the ONOs of the Buruktal deposit with the formation of ferronickel under the conditions that model melting in a barbotage unit is subjected to laboratory investigations. Wet or dried ore and its reduced cinder are melted. It is shown that melting of the reduced cinder of ONO can result in the formation of nickel-rich (up to 40% Ni) ferronickel upon the extraction of more than 91% nickel from the raw materials at a residual nickel content of <0.1% in a slag. Direct melting of the ore results in the formation of ferronickel with at most 18% Ni and a low degree of nickel extraction into ferronickel, which has high sulfur, phosphorus, and carbon contents in this case.

  18. Pancreas transplantation using type I and type II spontaneously diabetic rats--our experimental experience.

    PubMed

    Ito, Toshinori; Shimada, Kazunori; Gang, Miao; Uchikoshi, Fumihiro; Tori, Masayuki; Komoda, Hiroshi; Fumimoto, Yuichi; Ohmori, Ken; Kawamoto, Koichi; Tanemura, Masahiro; Nozawa, Masumi

    2007-01-01

    Pancreas transplantation (PTx) is the only therapy that can cure type 1 diabetes mellitus. With the recent advance of surgical procedures and immunosuppression, the outcome of PTx has become better than it used to be before, but some problems still remain. It is rather difficult to induce tolerance and to reverse rejection once it occurred because pancreas graft itself has a strong immunogenicity. Another important issue is regarding the recurrence of autoimmune disease in the pancreatic graft, therefore, some animal models are necessary to delineate and regulate those immune responses specific for PTx. Recently, PTx is also clinically applicable for type 2 diabetic patients with end-stage renal disease. It has been shown that insulin resistance was improved by PTx in type 2 diabetic recipients. In the current study, we have introduced some useful type 1 and type 2 diabetic models mainly based on our experimental experiences.

  19. Dynamic Light Scattering Microscopy. A Novel Optical Technique to Image Submicroscopic Motions. II: Experimental Applications

    PubMed Central

    Dzakpasu, Rhonda; Axelrod, Daniel

    2004-01-01

    An experimental verification of an optical microscope technique to create spatial map images of dynamically scattered light fluctuation decay rates is presented. The dynamic light scattering microscopy technique is demonstrated on polystyrene beads and living macrophage cells. With a slow progressive scan charge-coupled device camera employed in a streak-like mode, rapid intensity fluctuations with timescales the order of milliseconds can be recorded from these samples. From such streak images, the autocorrelation function of these fluctuations can be computed at each location in the sample. The characteristic decay times of the autocorrelation functions report the rates of motion of scattering centers. These rates show reasonable agreement to theoretically expected values for known samples with good signal/noise ratio. The rates can be used to construct an image-like spatial map of the rapidity of submicroscopic motions of scattering centers. PMID:15298931

  20. 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.

  1. A theory of local and global processes which affect solar wind electrons. II - Experimental support

    NASA Technical Reports Server (NTRS)

    Scudder, J. D.; Olbert, S.

    1979-01-01

    Strong observational support from data obtained on three different satellites and reported by three independent experimental groups is presented for all of the theoretically predicted correlations of a previous paper concerning local and global processes that affect solar-wind electrons. Specifically, it is shown that: (1) subthermal electrons behave most nearly as a classical gas; (2) the solar-wind extrathermal fraction of the electron density is anticorrelated within steady-state stream patterns with the local bulk speed; (3) the extrathermal electrons form a spectrally distinguishable subpopulation whose differential 'temperature' is anticorrelated with the local bulk speed; (4) the heat flux carried by electrons is anticorrelated with the bulk speed; and (5) the extrathermal 'temperature' is nearly independent of radius in the inner heliosphere. It is concluded that the previously discussed global and local Coulomb collisional effects are essential aspects of the solar-wind plasma as it is observed.

  2. 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

  3. 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

  4. 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.

  5. Plasmodium falciparum histidine-rich protein II causes vascular leakage and exacerbates experimental cerebral malaria in mice.

    PubMed

    Pal, Priya; Balaban, Amanda E; Diamond, Michael S; Sinnis, Photini; Klein, Robyn S; Goldberg, Daniel E

    2017-01-01

    A devastating complication of Plasmodium falciparum infection is cerebral malaria, in which vascular leakage and cerebral swelling lead to coma and often death. P. falciparum produces a protein called histidine-rich protein II (HRPII) that accumulates to high levels in the bloodstream of patients and serves as a diagnostic and prognostic marker for falciparum malaria. Using a human cerebral microvascular endothelial barrier model, we previously found that HRPII activates the endothelial cell inflammasome, resulting in decreased integrity of tight junctions and increased endothelial barrier permeability. Here, we report that intravenous administration of HRPII induced blood-brain barrier leakage in uninfected mice. Furthermore, HRPII infusion in P. berghei-infected mice increased early mortality from experimental cerebral malaria. These data support the hypothesis that HRPII is a virulence factor that contributes to cerebral malaria by compromising the integrity of the blood-brain barrier.

  6. Palladium(II) complexes bearing di-(2-picolyl)amine functionalized chrysin fragments. An experimental and theoretical study

    NASA Astrophysics Data System (ADS)

    González-Montiel, Simplicio; Valdez-Calderón, Alejandro; Vásquez-Pérez, J. Manuel; Torres-Valencia, J. Martín; Martínez-Otero, Diego; López, Jorge A.; Cruz-Borbolla, Julián

    2017-10-01

    A new series of chrysin derivatives containing the di-(2-picolyl)amine (2a-d) moiety have been designed, synthesized, and treated with PdCl2·2CH3CN allowing the preparation of new cationic Palladium(II) complexes (3a-d). Solution-phase studies by 1H NMR spectroscopy of 3a-d revealed that the protons of the methylene groups of the di(2-picolyl)amine fragment are diasterotopic. GIAO/DFT studies were performed to predict the molecular structures of 3a-d by comparing the experimental and theoretical 1H-NMR chemical shifts. The molecular structure of 3c was determined by X-ray crystallographic analysis revealing that di-(2-picolyl)amine fragment is coordinated to the palladium center in a κ3-N,N,N-tridentate fashion in an overall square-planar geometry completed with a chloride atom.

  7. Synthesis, experimental and theoretical characterization of a Mn(II) complex of N,N‧-dipyridoxyl(1,2-diaminobenzene)

    NASA Astrophysics Data System (ADS)

    Toozandejani, Tina; Beyramabadi, S. Ali; Chegini, Hamed; Khashi, Maryam; Morsali, Ali; Pordel, Mehdi

    2017-01-01

    Herein, hopping to biological and catalytic applications, synthesis of a Mn(II) complex of the N,N‧-dipyridoxyl(1,2-diaminobenzene) [Hdbnd 2L] Schiff-base has been reported. The Mn complex was characterized experimentally and theoretically. The optimized geometry and vibrational frequencies of the complex were computed by using the density functional theory (DFT) methods. In the optimized geometry of the octahedral complex, the dianionic L2- acts as a tetradentate ligand. Four coordination positions of the square plane have been occupied with two azomethine nitrogens and two phenolic oxygens of the L2- ligand. Two coordinated methanol ligands are perpendicular to the square plane. Also, properties of the Mnsbnd N and Mnsbnd O bonds were explored investigated using the Atoms in molecules (AIM) analysis.

  8. Differential parasitological, molecular, and serological detection of Trypanosoma cruzi I, II, and IV in blood of experimentally infected mice.

    PubMed

    Margioto Teston, Ana Paula; Paula de Abreu, Ana; Gruendling, Ana Paula; Bahia, Maria Terezinha; Gomes, Mônica Lúcia; Marques de Araújo, Silvana; Jean de Ornelas Toledo, Max

    2016-07-01

    Trypanosoma cruzi is the etiological agent of American trypanosomiasis (Chagas' disease), which affects 6-7 million people worldwide, mainly in Latin America. It presents great genetic and biological variability that plays an important role in the clinical and epidemiological features of the disease. Our working hypothesis is that the genetic diversity of T. cruzi has an important impact on detection of the parasite using diagnostic techniques. The present study evaluated the diagnostic performance of parasitological, molecular, and serological techniques for detecting 27 strains of T. cruzi that belonged to discrete typing units (DTUs) TcI (11 strains), TcII (four strains), and TcIV (12 strains) that were obtained from different hosts in the states of Amazonas and Paraná, Brazil. Blood samples were taken from experimentally infected mice and analyzed by fresh blood examination, hemoculture in Liver Infusion Tryptose (LIT) medium, polymerase chain reaction (PCR), and enzyme-linked immunosorbent assay (ELISA). Polymerase chain reaction presented the best detection of TcI, with 80.4% positivity. For all of the detection methods, the animals that were inoculated with TcII presented the highest positivity rates (94.1-100%). ELISA that was performed 7 months after inoculation presented a higher detection ability (95.4%) for TcIV. Intra-DTU comparisons showed that the reproducibility of the majority of the results that were obtained with the different methods was weak for TcI and good for TcII and TcIV. Our data indicate that the detection capability of different techniques varies with the DTUs of the parasites in mammalian blood. The implications of these findings with regard to the diagnosis of human T. cruzi infection are discussed. Copyright © 2016. Published by Elsevier Inc.

  9. The potential effect of the angiotensin II receptor blocker telmisartan in regulating OVA-induced airway remodeling in experimental rats.

    PubMed

    Abdel-Fattah, Maha M; Salama, Abeer A A; Shehata, Basim A; Ismaiel, Ismaiel E

    2015-10-01

    Bronchial asthma is a true ascending clinical problem. Angiotensin II is now accused to be potentially implicated in its pathogenesis, being a potent pro-inflammatory mediator with remodeling effects. This study aims to evaluate the possible protective effect of telmisartan, an angiotensin II receptor blocker, on experimentally-induced bronchial asthma. Animals were divided into 5 groups; a normal control group, an asthma control group, a reference treatment group, receiving dexamethasone, and two treatment groups, receiving telmisartan in two dose levels. Bronchial asthma was induced by intraperitoneal sensitization followed by intranasal challenge with ovalbumin (OVA). Test agents were administered prior to each intranasal OVA challenge. Lung function tests, namely tidal volume (TV) and peak expiratory flow rate (PEF) were assessed 1h after the last challenge. One day after the last challenge, absolute eosinophil counts (AEC) in blood and bronchoalveolar lavage fluids (BALF) were assessed. Serum immunoglobulin E (IgE) as well as BALF total nitrate/nitrite (NOx) were assessed. Oxidative and inflammatory biomarkers, namely lung tissue superoxide dismutase (SOD), glutathione reduced (GSH), tumor necrosis factor-alpha (TNF-α) and interleukin-5 (IL-5), were also assessed, in addition to histopathological study. Telmisartan administration in both doses significantly improved TV, PEF, AEC, IgE, NOx, GSH, SOD, TNF-α and IL-5 values compared to asthma control values. Histopathological study strongly supported the results of biochemical estimations, particularly regarding airway remodeling. These results suggest that telmisartan may have potential protecting effects against experimental bronchial asthma, probably due to its bronchodilator, antioxidant and anti-inflammatory effects. Copyright © 2015 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

  10. 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.

  11. 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.

  12. Highly Robust Palladium(II) α-Diimine Catalysts for Slow-Chain-Walking Polymerization of Ethylene and Copolymerization with Methyl Acrylate.

    PubMed

    Dai, Shengyu; Sui, Xuelin; Chen, Changle

    2015-08-17

    A series of sterically demanding α-diimine ligands bearing electron-donating and electron-withdrawing substituents were synthesized by an improved synthetic procedure in high yield. Subsequently, the corresponding Pd complexes were prepared and isolated by column chromatography. These Pd complexes demonstrated unique properties in ethylene polymerization, including high thermal stability and high activity, thus generating polyethylene with a high molecular weight and very low branching density. Similar properties were observed for ethylene/methyl acrylate copolymerization. Because of the high molecular weight and low branching density, the generated polyethylene and ethylene/methyl acrylate copolymer were semicrystalline solids. The (co)polymers had unique microstructures originating from the unique slow-chain-walking activity of these Pd complexes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. 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.

  14. 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.

  15. 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.

  16. Heat transfer with very high free-stream turbulence. I - Experimental data. II - Analysis of results

    NASA Technical Reports Server (NTRS)

    Maciejewski, P. K.; Moffat, R. J.

    1992-01-01

    Boundary layer heat transfer with very high freestream turbulence is investigated. The problem is studied experimentally by placing a constant-temperature heat transfer surface at various locations in the margin of a turbulent free jet and measuring both the surface heat transfer rate and the turbulence in the freestream. Freestream turbulent fluctuations 20 to 60 percent relative to the mean velocity augment heat transfer 1.8 to 4 times that which would be predicted locally using accepted correlations for turbulent boundary layers at the same Reynolds number. The correlations of Simonich and Bradshaw (1989), Pedisius et al. (1983), and Blair (1983) each fail to describe the present data. For flows over flat surfaces in air with very high freestream turbulence, greater than 0.2, u-prime determines h. A new heat transfer parameter, St-prime, characterizes turbulent boundary layer heat transfer with freestream turbulence on the domain 0-0.65 to within +/- 15 percent for high Reynolds number flows with uniform thermal boundary conditions.

  17. Experimental and numerical study of electrically driven magnetohydrodynamic flow in a modified cylindrical annulus. II. Instabilities

    NASA Astrophysics Data System (ADS)

    Stelzer, Zacharias; Miralles, Sophie; Cébron, David; Noir, Jérôme; Vantieghem, Stijn; Jackson, Andrew

    2015-08-01

    We present an investigation of the stability of liquid metal flow under the influence of an imposed magnetic field by means of a laboratory experiment as well as a linear stability analysis of the setup using the finite element method. The experimental device ZUrich Cylindrical CHannel INstability Investigation is a modified cylindrical annulus with electrically driven flow of liquid GaInSn operating at Hartmann and Reynolds numbers up to M = 2022 and Re = 2.6 ṡ 105, respectively. The magnetic field gives rise to a free shear layer at the prominent inner electrode. We identify several flow regimes characterized by the nature of the instabilities. Above a critical current I c = O ( 0 . 1 A ) , the steady flow is destabilized by a Kelvin-Helmholtz mechanism at the free shear layer. The instability consists of counterrotating vortices traveling with the mean flow. For low forcing, the vortices are restricted to the free shear layer. Their azimuthal wave number m grows with M and decreases with Re. At Re/M ≈ 25, the instability becomes container-filling and energetically significant. It enhances the radial momentum transport which manifests itself in a broadening of the free shear layer width δS. We propose that this transition may be related to an unstable Hartmann layer. At R e / M 2 = O ( 1 ) , an abrupt change is observed in the mean azimuthal velocity < u ϕ ¯ > and the friction factor F, which we interpret as the transition between an inertialess and an inertial regime.

  18. Levels of miRNA and Hormones in Thoracic Duct Lymph in Rats with Experimental Breast Cancer Induced by N-Methyl-N-Nitrosourea.

    PubMed

    Lykov, A P; Kabakov, A V; Kazakov, O V; Bondarenko, N A; Poveshchenko, O V; Raiter, T V; Poveshchenko, A F; Strunkin, D N; Konenkov, V I

    2017-01-01

    We studied hormone levels in the thoracic duct lymph and expression of miRNA involved in the pathogenesis of breast cancer induced in rats by intramammary injection of N-methyl-Nnitrosourea. The correlations between miRNA expression and hormone levels depended on the type of treatment.

  19. Excluded Volume Effects in Polymer Solutions: II. Comparison of Experimental Results with Numerical Simulation Data

    SciTech Connect

    Graessley, W.W.; Grest, G.S.; Hayward, R.C.

    1999-03-23

    The effect of excluded volume on the coil size of dilute linear polymers was investigated by off-lattice Monte Carlo simulations. The radius of gyration R{sub g} was evaluated for a wide range of chain lengths at several temperatures and at the athermal condition. The theta temperature and the corresponding theta chain dimensions were established for the system, and the dependence of the size expansion factor, a{sub s} = R{sub g} /(R{sub g}){sub {theta}}, on chain length N and temperature T was examined. For long chains and at high temperatures, a{sub s} is a function of N/N{sub s}{sup 2} alone, where the length scale N{sub s}{sup 2} depends only on T. The form of this simulations-based master function compares favorably with {alpha}{sub s}(M/M{sub s}{sup 2}), an experimental master curve for linear polymers in good solvents, where M{sub s}{sup 2} depends only on polymer-solvent system. Comparisons when N{sub s}{sup 2}(T) and M{sub s}{sup 2}(system) are reduced to common units, numbers of Kuhn steps, strongly indicate that coil expansion in even the best of good solvents is small relative to that expected for truly athermal solutions. An explanation for this behavior is proposed, based on what would appear to be an inherent difference in the equation of state properties for polymeric and monomeric liquids.

  20. Determination of erythrocyte transit times through micropores. II. Influence of experimental and physicochemical factors.

    PubMed

    Koutsouris, D; Guillet, R; Wenby, R B; Meiselman, H J

    1989-01-01

    A new red blood cell filtration system, termed the Cell Transit Time Analyzer (CTTA), has been developed in order to measure the individual transit times of a large number of cells through cylindrical micropores in special "oligopore" filters; the system operates on the electrical conductometric principle and employs special computer software to provide several measures of the resulting transit time histogram. Using this system with filters having pore diameters of 4.5 or 5.0 microns and length to diameter ratios of 3.0 to 4.7, we have evaluated the effects of several experimental factors on the flow behavior of normal and modified human RBC. Our results indicate: 1) linear RBC pressure-flow behavior over a driving pressure range of 2 to 10.5 cm H2O with zero velocity intercepts at delta P = 0, thus suggesting the Poiseuille-like nature of the flow; 2) resistance to flow or "apparent viscosities" for normal RBC which are between 3.1 to 3.9 cPoise and are independent of driving pressure and pore geometry; 3) increased flow resistance (i.e., increased transit times) for old versus young RBC and for RBC made less deformable by DNP-induced crenation or by heat treatment at 48 degrees C; 4) increased mean transit time and poorer reproducibility when using EDTA rather than heparin as the anticoagulant agent. Further, using mixtures of heat-treated and normal RBC and various percentile values of the transit time histogram, we have been able to demonstrate the presence of sub-populations of rigid cells and thus the value of measurements which allow statistical analyses of RBC populations.

  1. Advances in liquid phase soft-x-ray photoemission spectroscopy: A new experimental setup at BESSY II

    NASA Astrophysics Data System (ADS)

    Seidel, Robert; Pohl, Marvin N.; Ali, Hebatallah; Winter, Bernd; Aziz, Emad F.

    2017-07-01

    A state-of-the-art experimental setup for soft X-ray photo- and Auger-electron spectroscopy from liquid phase has been built for operation at the synchrotron-light facility BESSY II, Berlin. The experimental station is named SOL3, which is derived from solid, solution, and solar, and refers to the aim of studying solid-liquid interfaces, optionally irradiated by photons in the solar spectrum. SOL3 is equipped with a high-transmission hemispherical electron analyzer for detecting electrons emitted from small molecular aggregates, nanoparticles, or biochemical molecules and their components in (aqueous) solutions, either in vacuum or in an ambient pressure environment. In addition to conventional energy-resolved electron detection, SOL3 enables detection of electron angular distributions by the combination of a ±11° acceptance angle of the electron analyzer and a rotation of the analyzer in the polarization plane of the incoming synchrotron-light beam. The present manuscript describes the technical features of SOL3, and we also report the very first measurements of soft-X-ray photoemission spectra from a liquid microjet of neat liquid water and of TiO2-nanoparticle aqueous solution obtained with this new setup, highlighting the necessity for state-of-the-art electron detection.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. Clusters of DNA damage induced by ionizing radiation: Formation of short DNA fragments. II. Experimental detection

    SciTech Connect

    Rydberg, B.

    1996-02-01

    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. In particular, multiple DNA double-strand breaks and single-strand breaks may form. To test this experimentally, primary human fibroblasts were labeled with [{sup 3}H]thymidine and exposed at 0{degrees}C to X rays or accelerated nitrogen or iron ions in the LET range of 97-440 keV/pm. 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 {open_quotes}regionally multiply damaged sites.{close_quotes} 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. 34 refs., 6 figs., 1 tab.

  7. 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

  8. 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

  9. Methyl chloride

    Integrated Risk Information System (IRIS)

    EPA / 635 / R01 / 003 TOXICOLOGICAL REVIEW OF METHYL CHLORIDE ( CAS No . 74 - 87 - 3 ) In Support of Summary Information on the Integrated Risk Information System ( IRIS ) June 2001 U.S . Environmental Protection Agency Washington , DC DISCLAIMER This document has been reviewed in accordance with U.

  10. 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

  11. 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

  12. 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

  13. IOP induces upregulation of GFAP and MHC-II and microglia reactivity in mice retina contralateral to experimental glaucoma

    PubMed Central

    2012-01-01

    and OHT-eyes. By contrast, in macroglia, MHC-II upregulation was observed mainly in astrocytes in contralateral eyes and in Müller cells in OHT-eyes; vi) NF-200+RGCs (degenerated cells) appeared in OHT-eyes with a trend for the GFAP-RA to decrease and for the NF-200+RGC number to increase from the center to the periphery (r = −0.45). Conclusion The use of the contralateral eye as an internal control in experimental induction of unilateral IOP should be reconsidered. The gliotic behavior in contralateral eyes could be related to the immune response. The absence of NF-200+RGCs (sign of RGC degeneration) leads us to postulate that the MHC-II upregulation in contralateral eyes could favor neuroprotection. PMID:22583833

  14. 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.

  15. Cytotoxic effect of (1-methyl-1H-imidazol-2-yl)-methanamine and its derivatives in Pt(II) complexes on human carcinoma cell lines: a comparative study with cisplatin.

    PubMed

    Ferri, Nicola; Cazzaniga, Stefano; Mazzarella, Luca; Curigliano, Giuseppe; Lucchini, Giorgio; Zerla, Daniele; Gandolfi, Raffaella; Facchetti, Giorgio; Pellizzoni, Michela; Rimoldi, Isabella

    2013-04-15

    The synthesis and pharmacological characterisation of (1-methyl-1H-imidazol-2-yl)-methanamine and its derivatives in Pt(II) complexes are described. Six out of eleven new Pt(II) complexes showed a significant cytotoxic effect on NCI-H460 lung cancer cell line with EC50 values between 1.1 and 0.115 mM, determined by MTT assay. Compound Pt-4a showed a particularly more potent cytotoxic effect than the previously described Pt(II) complex with 2,2'-bipyridine, [Pt(bpy)Cl2], with an EC50 value equal to 172.7 μM versus 726.5 μM respectively, and similar potency of cisplatin (EC50=78.3 μM) in NCI-H460 cell line. The determination of the intracellular and DNA-bound concentrations of (195)Pt, as marker of the presence of the complexes, showed that the cytotoxic compound Pt-4a readily diffused into the cells to a similar extent of cisplatin and directly interacted with the nuclear DNA. Pt-4a induced both p53 and p21(Waf) expression in NCI-H460 cells similar to cisplatin. A direct comparison of the cytotoxic effect between compound Pt-4a and cisplatin on 12 different cancer cell lines demonstrated that compound Pt-4a was in general less potent than cisplatin, but it had a comparable cytotoxic effect on non-small-cell lung cancer NCI-H460 cells, and the colorectal cancer cells HCT-15 and HCT-116. Altogether, these results suggested that the Pt(II) complex with 1-methyl-1H-imidazol-2-yl)-methanamine (compound Pt-4a), displayed a significant cytotoxic activity in cancer cells. Similarly to cisplatin this compound interacts with nuclear DNA and induces both p53 and p21(waf), and thus it represents an interesting starting point for future optimisation of new Pt(II) complexes forming DNA adducts. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. A rapid synthesis of 2-substituted 1,2,3- triazole-1-oxide derivative starting from 4-(methyl)isonitrosoacetophenone and its Ni(II) complex: Characterization, DNA binding and cleavage properties

    NASA Astrophysics Data System (ADS)

    Gup, Ramazan; Erer, Oktay; Dilek, Nefise

    2017-02-01

    An efficient route, not including any metal salt as a catalyst, for the synthesis of a new 2-substituted 1,2,3- triazole-1-oxide is reported in this paper. The title compound has been synthesized via reacting 4-(methyl)isonitrosoacetophenone with hydrazine hydrate and dipyridyl ketone in high yield under mild reaction condition. The structure of the new 1,2,3-triazole-1-oxide has been characterized via single crystal X-ray and spectral studies. The 1:1 ratio reaction of the 1,2,3-triazole 1-oxide ligand with nickel(II) chloride gives the mononuclear complex [Ni(L)(DMF)(Cl)2] which is hexa-coordinated within an octahedral geometry. Characterization of the 1,2,3-triazole compound and its Ni(II) complex with FTIR, 1H and 13C NMR, UV-vis, TGA and elemental analysis also confirm the proposed structures for the compounds. The interactions of the compounds with Calf thymus DNA (CT-DNA) have been investigated via UV-visible spectra and viscosity measurements. The results suggested that both ligand and Ni(II) complex bind to DNA in electrostatic interaction and/or groove binding with a slight partial intercalation. DNA cleavage experiments have been also investigated by agarose gel electrophoresis in the presence and absence of an oxidative agent (H2O2). Both 1,2,3-triazole 1-oxide ligand and nickel(II) complex show nuclease activity, which significantly depends on concentrations of the compounds, both in the presence and absence of an oxidative agent. DNA binding and cleavage affinities of the Ni(II) complex is stronger than that of the 1,2,3-triazole 1-oxide ligand.

  17. Experimental and computational study on the reactivity of 2,3-bis[(3-pyridylmethyl)amino]-2(Z)-butene-1,4-dinitrile, a key intermediate for the synthesis of tribenzoporphyrazine bearing peripheral methyl(3-pyridylmethyl)amino substituents.

    PubMed

    Goslinski, Tomasz; Dutkiewicz, Zbigniew; Kryjewski, Michal; Tykarska, Ewa; Sobotta, Lukasz; Szczolko, Wojciech; Gdaniec, Maria; Mielcarek, Jadwiga

    An earlier developed alkylating path leading to tetraalkylated diaminomaleonitrile derivatives was explored. Attempts to explain the reactivity of the representative dialkylated diaminomaleonitrile 2,3-bis[(3-pyridylmethyl)amino]-2(Z)-butene-1,4-dinitrile during the alkylation reaction were performed using X-ray and density functional theory (DFT) studies. The condensed Fukui functions accompanied by softness indices were found to be useful in explaining its reactivity observed during the reaction. The values of the Fukui functions and condensed softness for electrophilic attack calculated from Mulliken, Löwdin, and natural population analyses closely corresponded to the experimental observations. When 2,3-bis[(3-pyridylmethyl)amino]-2(Z)-butene-1,4-dinitrile disodium salt was treated with dimethyl sulfate at lower temperatures the alkylation reaction prevailed, whereas at higher temperatures the alkylating agent acted as a hydride anion acceptor, which favored the elimination reaction. The tetraalkylated dinitrile 2,3-bis[methyl(3-pyridylmethyl)amino]-2(Z)-butene-1,4-dinitrile was used in the synthesis of tribenzoporphyrazine bearing methyl(3-pyridylmethyl)amino groups, which was subsequently subjected to solvatochromic and metallation studies. The changes observed during metallation seem to result from the coordination of the 3-pyridyl group by a palladium ion. This could influence the configuration of the methyl(3-pyridylmethyl)amino moiety, causing more effective donation of a lone pair of electrons from peripheral nitrogen to the macrocyclic ring. .

  18. Acetonitrile­dicarbon­yl(η5-penta­methyl­cyclo­penta­dien­yl)iron(II) tetra­fluorido­borate

    PubMed Central

    M’thiruaine, Cyprian M.; Friedrich, Holger B.; Changamu, Evans O.; Bala, Muhammad D.

    2011-01-01

    In the structure of the title compound, [Fe{η5-C5(CH3)5}(NCCH3)(CO)2]BF4, the arrangement of ligands around the Fe atom is in a pseudo-octa­hedral three-legged piano-stool fashion in which the penta­methyl­cyclo­penta­dienyl (Cp*) ligand occupies three apical coordination sites, while the two carbonyl and one acetonitrile ligands form the basal axes of the coordination. The Fe—N bond length is 1.924 (3) Å and the Fe—Cp* centroid distance is 1.722 Å. PMID:21836908

  19. Di-μ2-bromido-bis­[bromido(η6-1,2,4,5-tetra­methyl­benzene)ruthenium(II)

    PubMed Central

    Espinosa-Jalapa, Noel; Hernández-Ortega, Simón; Le Lagadec, Ronan; Morales-Morales, David

    2009-01-01

    The asymmetric unit of the title compound, [Ru2Br4(C10H14)2], contains one half of the centrosymmetric mol­ecule. Each Ru center is coordinated by tetra­methyl­benzene ring in a η6-coordination mode, and one terminal and two bridging bromine atoms. The aromatic rings and the Ru2Br2 four-membered ring form a dihedral angle of 55.99 (8)°. In the crystal structure, weak inter­molecular C—H⋯Br inter­actions link mol­ecules into chains propagated in [001]. PMID:21578690

  20. Theoretical and kinetic study of the reaction of ethyl methyl ketone with HO2 for T = 600-1600 K. Part II: addition reaction channels.

    PubMed

    Zhou, Chong-Wen; Mendes, Jorge; Curran, Henry J

    2013-06-06

    The temperature and pressure dependence of the addition reaction of ethyl methyl ketone (EMK) with HO2 radical has been calculated using the master equation method employing conventional transition state theory estimates for the microcanonical rate coefficients in the temperature range of 600-1600 K. Geometries, frequencies, and hindrance potentials were obtained at the B3LYP/6-311G(d,p) level of theory. A modified G3(MP2,CC) method has been used to calculate accurate electronic energies for all of the species involved in the reactions. The rigid-rotor harmonic oscillator approximation has been used for all of the vibrations except for the torsional degrees of freedom which are being treated as 1D hindered rotors. Asymmetric Eckart barriers were used to model tunneling effect in a one-dimensional reaction coordinate through saddle points. Our calculated results show that the four reaction channels forming 1-buten-2-ol + HO2 radical (R5), 2-buten-2-ol + HO2 radical (R10), acetic acid + ethylene + OH radical (R13), and 2-methyl-2-oxetanol + OH radical (R15) are the dominant channels. When the temperature is below 1000 K, the reaction R15 forming the cyclic ether, 2-methyl-2-oxetanol, is dominant while the reaction R13 forming acetic acid + ethylene + OH radical becomes increasingly dominant at temperatures above 1000 K. The other two channels forming 1-buten-2-ol, 2-buten-2-ol, and HO2 radical are not dominant but are still important product channels over the whole temperature range investigated here. No pressure dependence has been found for the reaction channels forming 2-methyl-2-oxetanol + OH radical and acetic acid + ethylene + OH radical. A slightly negative pressure dependence has been found for the reaction channels producing the two butenols. Rate constants for the four important reaction channels at 1 atm (in cm(3) mol(-1) s(-1)) are k(R5) = 2.67 × 10(15) × T(-1.32)exp(-16637/T), k(R10) = 1.62 × 10(8) × T(0.57)exp(-13142/T), k(R13) = 2.29 × 10(17) × T

  1. Origin of delayed fluorescence of a ladder-type methyl-poly( para-phenylene) doped with Pt(II)octaethylporphyrin

    NASA Astrophysics Data System (ADS)

    Bagnich, S. A.; Bässler, H.

    2003-11-01

    Luminescence of a ladder-type methyl-poly( para-phenylene) (MeLPPP) doped with 5% (by weight) platinum-porphyrin (PtOEP) has been investigated. It is shown that upon exciting in the spectral range of absorption of the guest the delayed fluorescence of the polymer is observed. Based upon field quenching of delayed fluorescence it is argued that it originates from an exciplex between PtOEP and MeLPPP generated by exciting the S 1 state of PtOEP.

  2. Crystal structure of poly[(4-amino-pyridine-κN)(N,N-di-methyl-formamide-κO)(μ3-pyridine-3,5-di-carboxyl-ato-κ(3) N:O (3):O (5))copper(II)].

    PubMed

    Shen, Cheng-Chen; Hua, Xiu-Ni; Han, Lei

    2016-04-01

    The title compound, [Cu(C7H3NO4)(C5H6N2)(C3H7NO] n , is an amino-function-alized chiral metal-organic framework with (10,3)-a topology. It has been constructed via the assembly of the achiral triconnected pyridine-3,5-di-carboxyl-ate (3,5-PDC) building block and a triconnected Cu(II) atom. Each Cu(II) 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 Cu(II) ion is completed by an N atom of a terminal 4-amino-pyridine (4-APY) ligand and the O atom of a terminal N,N-di-methyl-formamide (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.

  3. Crystal structure of hexa­aqua­nickel(II) bis­{5-bromo-7-[(2-hy­droxy­eth­yl)amino]-1-methyl-6-oxido­quinolin-1-ium-3-sulfonate} monohydrate

    PubMed Central

    Le Thi Hong, Hai; Nguyen Thi Ngoc, Vinh; Do Thi Van, Anh; Van Meervelt, Luc

    2016-01-01

    The asymmetric unit of the title compound, [Ni(H2O)6](C12H12BrN2O5S)2·H2O, contains a half hexa­aqua­nickel(II) complex cation with the NiII ion lying on an inversion center, one 5-bromo-7-[(2-hy­droxy­eth­yl)amino]-1-methyl-6-oxido­quinolin-1-ium-3-sulfonate (QAO) anion and a half lattice water mol­ecule on a twofold rotation axis. In the crystal, QAO anions are stacked in a column along the c axis by π–π stacking inter­actions [centroid–centroid distances 3.5922 (10)–3.7223 (11) Å]. The columns are inter­linked by hexa­aqua­nickel(II) cations through O—H⋯O and N—H⋯O hydrogen bonds. PMID:27920907

  4. Understanding the Excited State Behavior of Cyclometalated Bis(tridentate)ruthenium(II) Complexes: A Combined Experimental and Theoretical Study.

    PubMed

    Kreitner, Christoph; Erdmann, Elisa; Seidel, Wolfram W; Heinze, Katja

    2015-12-07

    The synthesis and characterization of the donor-acceptor substituted cyclometalated ruthenium(II) polypyridine complex isomers [Ru(dpb-NHCOMe)(tpy-COOEt)](PF6) 1(PF6) and [Ru(dpb-COOEt)(tpy-NHCOMe)](PF6) 2(PF6) (dpbH = 1,3-dipyridin-2-ylbenzene, tpy = 2,2';6,2"-terpyridine) with inverted functional group pattern are described. A combination of resonance Raman spectroscopic and computational techniques shows that all intense visible range absorption bands arise from mixed Ru → tpy/Ru → dpb metal-to-ligand charge transfer (MLCT) excitations. 2(PF6) is weakly phosphorescent at room temperature in fluid solution and strongly emissive at 77 K in solid butyronitrile matrix, which is typical for ruthenium(II) polypyridine complexes. Density functional theory calculations revealed that the weak emission of 2(PF6) arises from a (3)MLCT state that is efficiently thermally depopulated via metal-centered ((3)MC) excited states. The activation barrier for the deactivation process was estimated experimentally from variable-temperature emission spectroscopic measurements as 11 kJ mol(-1). In contrast, 1(PF6) is nonemissive at room temperature in fluid solution and at 77 K in solid butyronitrile matrix. Examination of the electronic excited states of 1(PF6) revealed a ligand-to-ligand charge-transfer ((3)LL'CT) as lowest-energy triplet state due to the very strong push-pull effect across the metal center. Because of the orthogonality of the participating ligands, emission from the (3)LL'CT is symmetry-forbidden. Hence, in this type of complex a stronger push-pull effect does not increase the phosphorescence quantum yields but completely quenches the emission.

  5. Computational and experimental study of the structure, binding preferences, and spectroscopy of nickel(II) and vanadyl porphyrins in petroleum.

    PubMed

    Stoyanov, Stanislav R; Yin, Cindy-Xing; Gray, Murray R; Stryker, Jeffrey M; Gusarov, Sergey; Kovalenko, Andriy

    2010-02-18

    We present a computational exploration of five- and six-coordinate Ni(II) and vanadyl porphyrins, including prediction of UV-vis spectroscopic behavior and metalloporphyrin structure as well as determination of a binding energy threshold between strongly bound complexes that have been isolated as single crystals and weakly bound ones that we detect by visible absorption spectroscopy. The excited states are calculated using the tandem of the time-dependent density functional theory (TD-DFT) and the conductor-like polarizable continuum model (CPCM). The excited-state energies in chloroform solvent obtained by using two density functionals are found to correlate linearly with the experimental Soret and alpha-band energies for a known series of five-coordinate vanadyl porphyrins. The established linear correction allows simulation of the excited states for labile octahedral vanadyl porphyrins that have not been isolated and yields Soret and alpha-band bathochromic shifts that are in agreement with our UV-vis spectroscopic results. The PBE0 and PW91 functionals in combination with DNP basis set perform best for both structure and binding energy prediction. The reactivity preferences of Ni(II) and vanadyl porphyrins toward aromatic fragments of large petroleum molecules are explored by using the density functional theory (DFT). Analysis of electrostatic potentials and Fukui functions matching shows that axial coordination and hydrogen bonding are the preferred aggregation modes between vanadyl porphyrins and nitrogen-containing heterocycle fragments. This investigation improves our understanding on the cause for broadening of the Ni and V porphyrin Soret band in heavy oils. Our findings can be useful for the development of metals removal methods for heavy oil upgrading.

  6. [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

  7. Human experimental exposure to N-methyl-2-pyrrolidone (NMP): toxicokinetics of NMP, 5-hydroxy- N-methyl-2-pyrrolidone, N-methylsuccinimide and 2-hydroxy- N-methylsuccinimide (2-HMSI), and biological monitoring using 2-HMSI as a biomarker.

    PubMed

    Jönsson, B A G; Akesson, B

    2003-05-01

    N-methyl-2-pyrrolidone (NMP) is a strong and selective organic solvent with an extensive and increasing use. It has been reported to be a compound that is toxic to the reproductive system. The aim of this study was to evaluate toxicokinetics parameters for NMP and its metabolites, 5-hydroxy- N-methyl-2- pyrrolidone (5-HNMP), N-methylsuccinimide (MSI) and 2-hydroxy- N-methylsuccinimide (2-HMSI), and to develop a method for biological monitoring of NMP exposure that uses 2-HMSI as a biomarker. Six healthy, male volunteers were exposed to NMP in an exposure chamber for 8 h at concentrations of 10, 25 and 50 mg/m(3). In addition, three of the subjects were exposed a second time at 50 mg/m(3). Air levels were monitored by Amberlite XAD-7 sampling and gas chromatography (GC) analysis. Levels of NMP and the metabolites in plasma and urine were analysed by GC or GC with mass spectrometry detection. The concentration of 2-HMSI in plasma and urine rose during exposure and reached a peak approximately 15 h after the end of exposure. It then decayed according to a one-compartment model with a half-time of about 18 h. There were very close correlations between the NMP air levels, on the one hand, and concentrations of 2-HMSI in plasma (r=0.98) and creatinine-adjusted urinary 2-HMSI levels (r=0.96), on the other. The renal clearances were 0.13, 1.4, 0.12 and 1.2 l/h for NMP, 5-HNMP, MSI and 2-HMSI, respectively. The total clearances were 11.4, 3.2, 8.5 and 1.1 l/h for NMP, 5-HNMP, MSI and 2-HMSI, respectively. The apparent volumes of distribution were 41, 28, 120 and 28 l for NMP, 5-HNMP, MSI and 2-HMSI, respectively. Toxicokinetics parameters for NMP, 5-HNMP, MSI and 2-HMSI have been estimated. Furthermore, 2-HMSI is applicable as a biomarker of exposure to NMP, and the levels in plasma and urine may be used to indicate an exposure over three days.

  8. catena-Poly[[[O,O′-bis­(2-methyl­phen­yl) dithio­phosphato-κ2 S,S]lead(II)]-μ-O,O′-bis­(2-methyl­phen­yl) dithio­phosphato-κ3 S,S′:S

    PubMed Central

    Butcher, Ray J.; Ratnani, Raju; Öztürk Yildirim, Sema; Falola, Oluwaseun

    2013-01-01

    In the title compound, [Pb(C14H14O2PS2)2]n, the metal atom is surrounded by two O,O′-bis­(2-methyl­phen­yl) dithio­phosphate ligands bonding through the S-donor atoms. Three of the Pb—S bond lengths are are close to each other at 2.7710 (18), 2.8104 (16) and 2.8205 (16) Å, while the fourth Pb—S bond is elongated at 3.0910 (18) Å and reflects the fact that this atom is involved in inter­molecular bridging to an adjacent PbII atom [Pb—S = 3.145 (2) Å]. The bond angles demonstrate that the PbII atom contains a stereochemically active lone pair with a distorted octa­hedral geometry about the PbII atom. This distortion is shown by the S—Pb—S bite angles of 73.63 (4) and 69.50 (4)°, while the remaining S—Pb—S angles range from 81.03 (5) to 143.66 (5)°. One of the benzene rings shows positional disorder over two orientations with occupancy factors of 0.747 (11) and 0.253 (11). PMID:23476328

  9. Purification of urease from jack bean (Canavalia ensiformis) with copper (II) chelated poly(hydroxyethyl methacrylate-N-methacryloyl-(L)-histidine methyl ester) cryogels.

    PubMed

    Tekiner, Pınar; Perçin, Işik; Ergün, Bahar; Yavuz, Handan; Aksöz, Erol

    2012-11-01

    Jack bean (Canavalia ensiformis) is the source of interesting proteins that contribute to modern biochemistry, and urease is the primary of these proteins. Owing to its role and occurrence in nature, urease has become a part of extensive studies. In this study, jack bean urease (JBU) was purified by immobilized metal affinity chromatography using Cu(2+) chelated poly(hydroxyethyl methacrylate-N-methacryloyl-(L)-histidine methyl ester) [PHEMAH-Cu(2+)]-based cryogels. PHEMAH-Cu(2+) cryogel was synthesized and characterized for swelling degree, morphology (by SEM), N-methacryloyl-(L)-histidine methyl ester and Cu(2+) incorporation (by elemental analysis and atomic absorption spectrophotometry). The binding of JBU to PHEMAH-Cu(2+) cryogel was optimized by examining the effect of pH, flow rate and JBU concentration on binding. The maximal binding of JBU was 23.2 mg/dry gram of adsorbent. The maximal binding of JBU extracted from jack bean meal was 67.8 mg/dry gram of adsorbent. The elution of JBU from cryogel column was accomplished by 1.0 M NaCl in 20 mM phosphate buffer (pH 8.0). Molecular weight and purity of JBU from jack bean meal was estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. It was observed that JBU could be repeatedly bound and eluted from (PHEMAH)-Cu(2+) cryogel with less than 10% loss in column capacity.

  10. [1,2-Bis(diphenyl­phosphino)ethane]­chlorido(η5-penta­methyl­cyclo­penta­dien­yl)iron(II) dichloro­methane solvate

    PubMed Central

    Ou, Ya-ping; Feng, Dan; Yuan, Jing-jing

    2010-01-01

    In the title compound, [Fe(C10H15)Cl(C26H24P2)]·CH2Cl2, the FeII atom is coordinated by two P atoms from a 1,2-bis­(diphenyl­phosphino)ethane ligand [Fe—P = 2.2130 (7) and 2.2231 (7) Å], a chloride anion [Fe—Cl = 2.3329 (7) Å] and a penta­methyl­cyclo­penta­dienyl (Cp*) ligand [Fe—centroid(Cp*) = 1.732 (3) Å] in a typical piano-stool geometry. In the crystal structure, the complex and solvent mol­ecules are paired via weak C—H⋯Cl inter­actions. PMID:21588156

  11. Dichloridobis[3-(4-meth­oxy­phen­yl)-2-methyl-5-(piperidin-1-yl)-2,3-di­hydro-1,2,4-oxa­diazole-κN 4]platinum(II)

    PubMed Central

    Kritchenkov, Andreii S.; Lavnevich, Leonid V.; Starova, Galina L.; Bokach, Nadezhda A.; Kalibabchuk, Valentina A.

    2013-01-01

    In title compound, [PtCl2(C15H21N3O2)2], the PtII cation, located on an inversion center, is coordinated by two Cl− anions and two 3-(4-meth­oxy­phen­yl)-2-methyl-5-(piperidin-1-yl)-2,3-di­hydro-1,2,4-oxa­diazole ligands in a distorted Cl2N2 square-planar geometry. The di­hydro­oxa­diazole and piperidine rings display envelope (with the non-coordinating N atom as the flap atom) and chair conformations, respectively. In the crystal, weak C—H⋯Cl hydrogen bonds link the mol­ecules into supra­molecular chains running along the b axis. The piperidine ring is disordered over two positions with the occupancy ratio of 0.528 (4):0.472 (4). PMID:24109266

  12. Synthesis, spectroscopic studies and nonlinear optical behavior of N,N‧-bis(2-hydroxy-1-naphthylmethylidene)-1-methyl-1,2-diaminoethane-N,N‧,O,O‧-nickel(II)

    NASA Astrophysics Data System (ADS)

    Ünver, Hüseyin; Elmali, Ayhan; Karakaş, Aslı; Kara, Hülya; Donmez, Emine

    2006-12-01

    A Schiff base complex N, N'-bis(2-hydroxy-1-naphthylmethylidene)-1-methyl-1,2- diaminoethane- N, N', O, O'-nickel(II) has been synthesized. The title compound has been characterized by FT-IR and UV-vis spectroscopies. The UV-vis experiments indicate that the compound has solvatochromism in the UV region, implying non-zero molecular first hyperpolarizability. To investigate microscopic second-order nonlinear optical (NLO) behavior of the examined complex, the electric dipole moments ( μ) and the first static hyperpolarizabilities ( β) were computed using Finite Field second-order Møller Plesset (FF MP2) perturbation procedure. According to ab initio quantum mechanical calculations, the title complex exhibits non-zero β values, revealing microscopic second-order NLO behavior.

  13. Diaqua­bis­{2-hy­droxy-5-[(pyridin-2-yl)methyl­idene­amino]­benzoato-κ2 N,N′}nickel(II) dihydrate

    PubMed Central

    Zha, Meiqin; Li, Xing; Bing, Yue; Luo, Zhengbing

    2010-01-01

    In the title complex, [Ni(C13H9N2O3)2(H2O)2]·2H2O, the NiII atom, located on a twofold rotation axis, is in a distorted octa­hedral geometry, defined by four N atoms from two 2-hy­droxy-5-[(pyridin-2-yl)methyl­idene­amino]­benzoate ligands and two O atoms from two water mol­ecules. In the crystal, inter­molecular O—H⋯O hydrogen bonds link the complex mol­ecules and uncoordinated water mol­ecules into a three-dimensional network. Intra­molecular O—H⋯O hydrogen bonds are present between the hy­droxy and carboxyl­ate groups. PMID:21589257

  14. catena-Poly[[chloridocopper(II)]bis­(μ-3,3′,5,5′-tetra­methyl-4,4′-methylene­dipyrazole)[chloridocopper(II)]-di-μ-chlorido

    PubMed Central

    Wang, Zhi-Min

    2008-01-01

    In the title compound, [Cu2Cl4(C11H16N4)]n, the Cu atom is coordinated by two N atoms of two 3,3′,5,5′-tetra­methyl-4,4′-methyl­enedipyrazole (H2mbdpz) ligands, two bridging Cl atoms and one terminal Cl atom, forming a square-pyramidal geometry. The bridging Cl atoms and the bridging H2mbdpz ligands connect the Cu atoms to build up an extended one-dimensional chain. The chains are further connected through N—H⋯Cl hydrogen bonds to build up a two-dimensional layer in the (011) plane. An inversion centre lies between every pair of adjacent Cu atoms. PMID:21202017

  15. Methyl eucomate

    PubMed Central

    Li, Linglin; Zhou, Guang-Xiong; Jiang, Ren-Wang

    2008-01-01

    The crystal structure of the title compound [systematic name: methyl 3-carboxy-3-hydr­oxy-3-(4-hydroxy­benz­yl)propanoate], C12H14O6, is stabilized by inter­molecular O—H⋯O and C—H⋯O hydrogen bonds. The mol­ecules are arranged in layers, parallel to (001), which are inter­connected by the O—H⋯O hydrogen bonds. PMID:21202973

  16. A new one-dimensional Zn(II) coordination polymer based on 2-[(1H-imidazol-1-yl)methyl]-1H-benzimidazole and benzene-1,2-dicarboxylate.

    PubMed

    Huang, Qiu-Ying; Liu, Wei; Yang, Yi; Meng, Xiang-Ru

    2015-11-01

    Multidentate N-heterocyclic compounds form a variety of metal complexes with many intriguing structures and interesting properties. The title coordination polymer, catena-poly[zinc(II)-bis{μ-2-[(1H-imidazol-1-y