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Sample records for ii experimental methyl

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

    SciTech Connect

    Tretiak, Sergei

    2008-01-01

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

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

    PubMed

    Kusmariya, Brajendra S; Mishra, A P

    2015-11-01

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

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

    SciTech Connect

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

    2008-12-15

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

  4. Experimental and quantum-chemical studies of 1H, 13C and 15N NMR coordination shifts in Pd(II) and Pt(II) chloride complexes with methyl and phenyl derivatives of 2,2'-bipyridine and 1,10-phenanthroline.

    PubMed

    Pazderski, Leszek; Tousek, Jaromír; Sitkowski, Jerzy; Kozerski, Lech; Szłyk, Edward

    2007-12-01

    1H, 13C and 15N NMR studies of platinide(II) (M=Pd, Pt) chloride complexes with methyl and phenyl derivatives of 2,2'-bipyridine and 1,10-phenanthroline [LL=4,4'-dimethyl-2,2'-bipyridine (dmbpy); 4,4'-diphenyl-2,2'-bipyridine (dpbpy); 4,7-dimethyl-1,10-phenanthroline (dmphen); 4,7-diphenyl-1,10-phenanthroline (dpphen)] having a general [M(LL)Cl2] formula were performed and the respective chemical shifts (delta1H, delta13C, delta15N) reported. 1H high-frequency coordination shifts (Delta1Hcoord=delta1Hcomplex-delta1Hligand) were discussed in relation to the changes of diamagnetic contribution in the relevant 1H shielding constants. The comparison to literature data for similar [M(LL)(XX)], [M(LL)X2] and [M(LL)XY] coordination or organometallic compounds containing various auxiliary ligands revealed a large dependence of delta1H parameters on inductive and anisotropic effects. 15N low-frequency coordination shifts (Delta15Ncoord=delta 15Ncomplex-delta15Nligand) of ca 88-96 ppm for M=Pd and ca 103-111 ppm for M=Pt were attributed to both the decrease of the absolute value of paramagnetic contribution and the increase of the diamagnetic term in the expression for 15N shielding constants. The absolute magnitude of Delta15Ncoord parameter increased by ca 15 ppm upon Pd(II)-->Pt(II) transition and by ca 6-7 ppm following dmbpy-->dmphen or dpbpy-->dpphen ligand replacement; variations between analogous complexes containing methyl and phenyl ligands (dmbpy vs dpbpy; dmphen vs dpphen) did not exceed+/-1.5 ppm. Experimental 1H, 13C, 15N NMR chemical shifts were compared to those quantum-chemically calculated by B3LYP/LanL2DZ+6-31G**//B3LYP/LanL2DZ+6-31G*, both in vacuo and in DMSO or DMF solution. PMID:18044804

  5. Experimental test accelerator (ETA) II

    SciTech Connect

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

    1981-03-06

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

  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. Angiotensin II during Experimentally Simulated Central Hypovolemia

    PubMed Central

    Jensen, Theo Walther; Olsen, Niels Vidiendal

    2016-01-01

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

  9. Methyl deficient diet aggravates experimental colitis in rats.

    PubMed

    Chen, Min; Peyrin-Biroulet, Laurent; George, Amandine; Coste, Florence; Bressenot, Aude; Bossenmeyer-Pourie, Carine; Alberto, Jean-Marc; Xia, Bing; Namour, Bernard; Guéant, Jean-Louis

    2011-11-01

    Inflammatory bowel diseases (IBD) result from complex interactions between environmental and genetic factors. Low blood levels of vitamin B12 and folate and genetic variants of related target enzymes are associated with IBD risk, in population studies. To investigate the underlying mechanisms, we evaluated the effects of a methyl-deficient diet (MDD, folate, vitamin B12 and choline) in an experimental model of colitis induced by dextran sodium sulphate (DSS), in rat pups from dams subjected to the MDD during gestation and lactation. Four groups were considered (n = 12-16 per group): C DSS(-) (control/DSS(-)), D DSS(-) (deficient/DSS(-)), C DSS(+) (control/DSS(+)) and D DSS(+) (deficient/DSS(+)). Changes in apoptosis, oxidant stress and pro-inflammatory pathways were studied within colonic mucosa. In rat pups, the MDD produced a decreased plasma concentration of vitamin B12 and folate and an increased homocysteine (7.8 ± 0.9 versus 22.6 ± 1.2 μmol/l, P < 0.001). The DSS-induced colitis was dramatically more severe in the D DSS(+) group compared with each other group, with no change in superoxide dismutase and glutathione peroxidase activity, but decreased expression of caspase-3 and Bax, and increased Bcl-2 levels. The mRNA levels of tumour necrosis factor (TNF)-α and protein levels of p38, cytosolic phospolipase A2 and cyclooxygenase 2 were significantly increased in the D DSS(+) pups and were accompanied by a decrease in the protein level of tissue inhibitor of metalloproteinases (TIMP)3, a negative regulator of TNF-α. MDD may cause an overexpression of pro-inflammatory pathways, indicating an aggravating effect of folate and/or vitamin B12 deficiency in experimental IBD. These findings suggest paying attention to vitamin B12 and folate deficits, frequently reported in IBD patients. PMID:21199330

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

    SciTech Connect

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

    1996-01-01

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

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

    SciTech Connect

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

    2011-01-01

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

  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. IGFBP-3 Gene Methylation in Primary Tumor Predicts Recurrence of Stage II Colorectal Cancers

    PubMed Central

    Fu, Tao; Pappou, Emmanouil P.; Guzzetta, Angela A.; de Freitas Calmon, Marilia; Sun, Lifeng; Herrera, Alexander; Li, Fan; Wolfgang, Christopher L.; Baylin, Stephen B.; Iacobuzio-Donahue, Christine A.; Tong, Weidong; Ahuja, Nita

    2015-01-01

    Objectives To evaluate the influence of IGFBP-3 methylation on recurrence in patients with stage II colorectal cancer (CRC) from 2 independent cohorts. Background The relationship between IGFBP-3 methylation in primary tumors (PTs) or lymph nodes (LNs) and risk of recurrence in patients with stage II CRC treated with surgery alone is unknown. Methods IGFBP-3 methylation of DNA from 115 PTs and 1641 LNs in patients with stage II CRC from 2 independent cohorts was analyzed. Forty patients developed recurrence, whereas 75 matched patients remained recurrence free for more than 2 years after surgery. Cox proportional hazard models were used to calculate hazard ratios (HRs) of recurrence, adjusted for patient and tumor characteristics. Results Methylation of IGFBP-3 in PTs was identified to be significantly associated with risk of recurrence in the training set. The signature was tested in a validation set and classified 40.7% of patients as high risk. Five-year recurrence-free survival rates were 76.4% and 58.3% for low- and high-risk patients, respectively, with an HR of 2.21 (95% confidence interval, 1.04–4.68; P = 0.039). In multivariate analysis, the signature remained the most significant prognostic factor, with an HR of 2.40 (95% confidence interval, 1.10–5.25; P = 0.029). A combined analysis of 1641 LNs from the 2 sets identified IGFBP-3 methylation in LNs was not associated with risk of recurrence. Conclusions Detection of IGFBP-3 methylation in PTs, but not in LNs, provides a powerful tool for the identification of patients with stage II CRC at high risk of recurrence. PMID:25822686

  14. Quantitative Assessment of Protein Interaction with Methyl-Lysine Analogues by Hybrid Computational and Experimental Approaches

    PubMed Central

    2011-01-01

    In cases where binding ligands of proteins are not easily available, structural analogues are often used. For example, in the analysis of proteins recognizing different methyl-lysine residues in histones, methyl-lysine analogues based on methyl-amino-alkylated cysteine residues have been introduced. Whether these are close enough to justify quantitative interpretation of binding experiments is however questionable. To systematically address this issue, we developed, applied, and assessed a hybrid computational/experimental approach that extracts the binding free energy difference between the native ligand (methyl-lysine) and the analogue (methyl-amino-alkylated cysteine) from a thermodynamic cycle. Our results indicate that measured and calculated binding differences are in very good agreement and therefore allow the correction of measured affinities of the analogues. We suggest that quantitative binding parameters for defined ligands in general can be derived by this method with remarkable accuracy. PMID:21991995

  15. The antibody response to methyl isocyanate: experimental and clinical findings.

    PubMed

    Karol, M H; Kamat, S R

    1987-01-01

    Sera from 99 subjects exposed to the industrial gas leak in Bhopal on December 2, 1984 were studied along with sera from guinea pigs exposed to methyl isocyanate (MIC) to determine the production of antibodies specific to (MIC). Each of the four guinea pigs injected with the reactive isocyanate produced MIC-specific antibodies in titres of 1:5120 to 1:10240, when tested with MIC-guinea pig albumin antigen conjugate. Analogous antigens prepared by reaction of MIC with human serum albumin were used to probe production of antibodies in 264 serially obtained human sera from 99 subjects from Bhopal. MIC-specific antibodies belonging to IgG, IgM and IgE classes were detected in eleven subjects. Though titres were low and transient (declining after several months) these findings indicate that the single large exposure to MIC resulted in an immunologic response. This finding was concomitant with chronic respiratory effects following MIC exposure. PMID:3453753

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

    PubMed

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

    2014-05-01

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

  17. 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.

  18. Poly[1-ethyl-3-methyl­imidazolium [tri-μ-chlorido-chromate(II)

    PubMed Central

    Danford, James J.; Arif, Atta M.; Berreau, Lisa M.

    2009-01-01

    The title compound, {(C6H11N2)[CrCl3]}n, was generated via mixing of the ionic liquid 1-ethyl-3-methyl­imidazolium chloride with CrCl2 in ethanol. Crystals were obtained by a diffusion method. In the crystal structure, the anion forms one-dimensional chains of chloride-bridged Jahn–Teller distorted chromium(II) centers extending along the [100] direction. The imidazolium cations are positioned between these chains. PMID:21581818

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

    PubMed

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

    2011-11-30

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

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

    SciTech Connect

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

    1988-07-13

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

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

    NASA Astrophysics Data System (ADS)

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

    2008-01-01

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

  2. 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

  3. 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

  4. 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)

  5. 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

  6. Bis(2-amino-3-methyl­pyridine-κN 1)dichloridomercury(II)

    PubMed Central

    Tadjarodi, Azadeh; Bijanzad, Keyvan; Notash, Behrouz

    2012-01-01

    In the title compound, [HgCl2(C6H8N2)2], the two independent HgII cations are each located on a twofold rotation axis and coordinated by two pyridine N atoms from two 2-amino-3-methyl­pyridine ligands and two Cl− anions in a distorted tetra­hedral geometry. An intra­molecular N—H⋯Cl hydrogen bond occurs in each independent complex mol­ecule. Inter­molecular N—H⋯Cl hydrogen bonds occur in the crystal structure. PMID:22904756

  7. Dichlorido(6-methyl-2,2′-bipyridine-κ2 N,N′)zinc(II)

    PubMed Central

    Ahmadi, Roya; Kalateh, Khadijeh; Ebadi, Amin; Amani, Vahid; Khavasi, Hamid Reza

    2008-01-01

    In the mol­ecule of the title compound, [ZnCl2(C11H10N2)], the ZnII atom is four-coordinated in a distorted tetra­hedral configuration by two N atoms from the 6-methyl-2,2′-bipyridine ligand and by two Cl atoms. There are π–π contacts between the pyridine ring and the five-membered ring, and also between the pyridine rings, [centroid–centroid distances = 3.685 (3) and 3.757 (3) Å, respectively]. PMID:21201019

  8. Bis(2-amino-3-methyl­pyridine)­dichlorido­cobalt(II)

    PubMed Central

    Tadjarodi, Azadeh; Bijanzad, Keyvan; Notash, Behrouz

    2010-01-01

    In the title compound, [CoCl2(C6H8N2)2], the CoII ion is four-coordinated by two pyridine N atoms from the 2-amino-3-methyl­pyridine ligands and two chloride ions in a distorted tetra­hedral geometry. A weak intra­molecular N—H⋯Cl inter­action occurs. The crystal packing is stabilized by inter­molecular N—H⋯Cl and C—H⋯Cl hydrogen-bond inter­actions. PMID:21587434

  9. Methylation of CIITA promoter IV causes loss of HLA-II inducibility by IFN-γ in promyelocytic cells

    PubMed Central

    De Ambrosis, Alessandro; Banelli, Barbara; Pira, Giuseppina Li; Aresu, Ottavia; Romani, Massimo; Ferrini, Silvano; Accolla, Roberto S.

    2008-01-01

    The human promyelocytic cell line THP-1 expresses high level of HLA class II (HLA-II) molecules after IFN-γ treatment. Here, we report a variant of THP-1 that does not express HLA-II after IFN-γ. The variant's HLA-II phenotype is constant over time in culture and it is not related to a defective IFN-γ-signalling pathway. Transfection of CIITA, the HLA-II transcriptional activator, under the control of a cytomegalovirus promoter rescues high level of HLA-DR surface expression in the variant indicating that the biosynthetic block resides in the expression of CIITA and not in the CIITA-dependent transactivation of the HLA-II promoters. Treatment of the variant with 5-azacytidine (5-aza), which inhibits CpG methylation, restores inducibility of HLA-II by IFN-γ both at transcriptional and phenotypic level and antigen presenting and processing function of the variant. DNA studies demonstrate that the molecular defect of the THP-1 variant originates from the methylation of the CIITA promoter IV. Furthermore, treatment with 5-aza produces a substantial demethylation of CIITA promoter IV and a significant increase of IFN-γ-dependent HLA-II expression in another myelomonocytic cell line, U937. Therefore hyper-methylation of CIITA promoter IV may be a relevant mechanism of epigenetic control preventing HLA-II IFN-γ inducibility in the myelomonocytic cell lineage. PMID:18829986

  10. Data handling at EBR-II (Experimental Breeder Reactor II) for advanced diagnostics and control work

    SciTech Connect

    Lindsay, R.W.; Schorzman, L.W.

    1988-01-01

    Improved control and diagnostics systems are being developed for nuclear and other applications. The Experimental Breeder Reactor II (EBR-II) Division of Argonne National Laboratory has embarked on a project to upgrade the EBR-II control and data handling systems. The nature of the work at EBR-II requires that reactor plant data be readily available for experimenters, and that the plant control systems be flexible to accommodate testing and development needs. In addition, operational concerns require that improved operator interfaces and computerized diagnostics be included in the reactor plant control system. The EBR-II systems have been upgraded to incorporate new data handling computers, new digital plant process controllers, and new displays and diagnostics are being developed and tested for permanent use. In addition, improved engineering surveillance will be possible with the new systems.

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

    PubMed

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

    2015-03-01

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

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

    PubMed Central

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

    2015-01-01

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

  13. Comparative analysis of the cytotoxicity of substituted (phenylglyoxal bis(4-methyl-3-thiosemicarbazone)) copper (II) chelates.

    PubMed

    Coats, E A; Milstein, S R; Holbein, G; McDonald, J; Reed, R; Petering, H G

    1976-01-01

    Seven para-substituted [phenylglyoxal bis(4-methyl-3-thiosemicarbazone)]copper (II) chelates (12-18) have been designed, synthesized, and tested for their ability to inhibit the respiration of rat liver slices as a normal cell model and Ehrlich ascites cells as a tumor cell model. Relationships between chemical structure and respiratory inhibition are described on a quantitative basis using substituent contants (pi, Es, and sigmap) by computerized multiparameter regression analyses. The correlations indicate that changes in Es have the largest effect on liver slice toxicity of chelates while pi and sigmap account for most of the variation in toxicity to ascites cells. A comparative analysis strongly suggests that electron-donating substituents with greater water solubility should increase cytotoxicity to ascites cells at the expense of cytotoxicity to the rat liver cells. The predictions of the equations were checked by synthesizing and testing an additional derivative. The results strengthen the initial predictions. PMID:1246035

  14. Photo-induced electron transfer between a dendritic zinc(II) phthalocyanine and methyl viologen

    NASA Astrophysics Data System (ADS)

    Wang, Yuhua; Chen, Jiangxu; Huang, Lishan; Xie, Shusen; Yang, Hongqin; Peng, Yiru

    2013-01-01

    The intermolecular electron transfer between the carboxylic dendritic zinc(II) phthalocyanines [G1-ZnPc( and G2-ZnPc(] and methyl viologen (MV) is studied by steady-state fluorescence and UV/Vis absorption spectroscopic method. The effect of dendron generation of this series of dendritic phthalocyanines on intermolecular electron transfer is investigated. The results show that the fluorescence emission of these dendritic phthalocyanines could be greatly quenched by MV upon excitation at 610 nm. The Stern-Volmer constant (KSV) of electron transfer is decreased with increasing dendron generations. Our study suggests that these dendritic phthalocyanines are an effective new electron donor and transmission complex and could be used as a potential artificial photosynthesis system.

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

    PubMed

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

    2004-03-01

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

  16. 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.

  17. 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. PMID:12480941

  18. 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. PMID:24260216

  19. 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.

  20. 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.

  1. Synthesis, structure and biological activity of nickel(II) complexes of 5-methyl 2-furfural thiosemicarbazone.

    PubMed

    Jouad, E M; Larcher, G; Allain, M; Riou, A; Bouet, G M; Khan, M A; Thanh, X D

    2001-09-01

    5-Methyl 2-furfuraldehyde thiosemicarbazone (M5HFTSC) with nickel(II) leads to three types of complexes: [Ni(M5HFTSC)(2)X(2)], [Ni(M5FTSC)(2)] and [Ni(M5FTSC)(2)] x 2DMF. In the first type the ligand remains in thione form, while in the two other, the anionic thiolato form is involved. The species [Ni(M5HFTSC)(2)X(2)] has been characterized spectroscopically. The structures of [Ni(M5FTSC)(2)] x 2DMF and [Ni(M5FTSC)(2)] have been solved using X-ray diffraction. Biological studies of [Ni(M5HFTSC)(2)Cl(2)] have been carried out in vitro for antifungal activity on human pathogenic fungi, Aspergillus fumigatus and Candida albicans, and in vivo for toxicity on mice. The results are compared to those of the ligand, the metal salt and a similar copper complex [Cu(M5HFTSC)Cl(2)]. PMID:11566328

  2. 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).

  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. 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.

  5. Experimental Breeder Reactor II (EBR-II) Fuel-Performance Test Facility (FPTF)

    SciTech Connect

    Pardini, J.A.; Brubaker, R.C.; Veith, D.J.; Giorgis, G.C.; Walker, D.E.; Seim, O.S.

    1982-01-01

    The Fuel-Performance Test Facility (FPTF) is the latest in a series of special EBR-II instrumented in-core test facilities. A flow control valve in the facility is programmed to vary the coolant flow, and thus the temperature, in an experimental-irradiation subassembly beneath it and coupled to it. In this way, thermal transients can be simulated in that subassembly without changing the temperatures in surrounding subassemblies. The FPTF also monitors sodium flow and temperature, and detects delayed neutrons in the sodium effluent from the experimental-irradiation subassembly beneath it. This facility also has an acoustical detector (high-temperature microphone) for detecting sodium boiling.

  6. 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.

  7. 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.

  8. 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. PMID:22842335

  9. 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 ...

  10. 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

  11. 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

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

    SciTech Connect

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

    2002-09-26

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

  13. 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.

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

    PubMed

    Matjacić, Z; Bajd, T

    1998-06-01

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

  15. Experimental oscillator strengths of highly excited levels of Mo II

    NASA Astrophysics Data System (ADS)

    Aragón, C.; Aguilera, J. A.; Ortiz, M.; Mayo-García, R.

    2016-05-01

    Measurements of 161 oscillator strengths arising from highly excited levels of Mo II are presented, 148 of which are obtained for the first time. These results extend the previous ones already published on lower excited levels of Mo II. A laser-induced plasma generated from a fused glass sample prepared from molybdenum oxide with a Mo atomic concentration of 0.1% was used to obtain the presented radiative parameters via laser-induced breakdown spectroscopy. Measurements were carried out with an electron density of (2.5 ± 0.1) · 1017 cm‑3 and an electron temperature of 14 400 ± 200 K as the plasma evolved in air at atmospheric pressure. As a consequence, an optically thin plasma and a local thermodynamic equilibrium environment were then present in the measurements. In order to put on an absolute scale the relative intensities, both the combination of branching fractions with measured lifetimes and the comparison of well-known lines using the plasma temperature were carried out. Also, the new results are compared with previously theoretical and obtained experimental values wherever possible.

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

    NASA Astrophysics Data System (ADS)

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

    2009-10-01

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

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

    PubMed

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

    2002-11-25

    Alcoholic solutions of FeCl(2) and Fe(II)(Hmmi)(2)Cl(2) (Hmmi=1-methyl-2-mercaptoimidazole) induce calf thymus DNA condensation from aqueous solutions buffered at pH 7.4. A 1:1 Fe(II)-(DNA monomer) stoichiometry is assumed. The (57)Fe Mössbauer hyperfine parameters suggest an octahedral coordination environment, severely distorted, in both Fe(II)-(DNA monomer) and [Fe(II)(Hmmi)(2)]-(DNA monomer) condensates. The dynamic properties of iron nuclei in freeze-dried samples were investigated by means of variable temperature (57)Fe Mössbauer spectroscopy. Mean square displacements, (T), were calculated, such as the effective vibrating mass and the Mössbauer lattice temperature of the solids. increases linearly with the temperature in the whole temperature range explored; the absolute values are typical for lattice or solid-state vibrations. Very similar values for the effective vibrating masses were extracted, suggesting comparable covalency of the bonding interaction between the metal atom and its ligands, while the Mössbauer lattice temperatures show a softening of the lattice for [Fe(II)(Hmmi)(2)]-(DNA monomer) with respect to Fe(II)-(DNA monomer) condensate. PMID:12433425

  18. The Complete, Temperature Resolved Experimental Spectrum of Methyl Formate (HCOOCH3) between 214.6 and 265.4 GHz

    NASA Astrophysics Data System (ADS)

    McMillan, James P.; Fortman, Sarah M.; Neese, Christopher F.; De Lucia, Frank C.

    2016-05-01

    Because methyl formate (HCOOCH3) is abundant in the interstellar medium and has a strong, complex spectrum, it is a major contributor to the list of identified astrophysical lines. Because of its spectral complexity, with many low lying torsional and vibrational states, the quantum mechanical (QM) analysis of its laboratory spectrum is challenging and thus incomplete. As a result it is assumed that methyl formate is also one of the major contributors to the lists of unassigned lines in astrophysical spectra. This paper provides a characterization, without the need for QM analysis, of the spectrum of methyl formate between 214.6 and 265.4 GHz for astrophysically significant temperatures. The experimental basis for this characterization is a set of 425 spectra, with absolute intensity calibration, recorded between 248 and 408 K. Analysis of these spectra makes possible the calculation of the Complete Experimental Spectrum of methyl formate as a function of temperature. Of the 7132 strongest lines reported in this paper, 2523 are in the QM catalogs. Intensity differences of 5%–10% from those calculated via QM models were also found. Results are provided in a frequency point-by-point catalog that is well suited for the simulation of overlapped spectra. The common astrophysical line frequency, line strength, and lower state energy catalog is also provided.

  19. Photo-induced electron transfer between dendritic zinc(II) phthalocyanine bearing carboxylic terminal groups and methyl viologen

    NASA Astrophysics Data System (ADS)

    Wang, Yuhua; Chen, Jiangxu; Huang, Lishan; Xie, Shusen; Yang, Hongqin; Peng, Yiru

    2012-12-01

    The intermolecular electron transfer between carboxylic dendritic zinc(II) phthalocyanine bearing carboxylic terminal groups(G1-ZnPc(COOH)8) and methyl viologens (MV2+) was studied by steady-state fluorescence and UV/Vis spectroscopy. The effect of different concentrations of MV2+ on intermolecular electron transfer was investigated. The results show that the fluorescence emission of this dendritic phthalocyanine could be greatly quenched with an increasing amount of MV2+ upon excitation at 610 nm. Our study suggests that this novel dendritic phthalocyanine is an effective new electron donor and transmission complex and could be used as a potential biosensor conjugated with suitable fluorescence quencher.

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

    SciTech Connect

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

    1996-01-01

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

  1. PRMT9 is a Type II methyltransferase that methylates the splicing factor SAP145

    PubMed Central

    Yang, Yanzhong; Hadjikyriacou, Andrea; Xia, Zheng; Gayatri, Sitaram; Kim, Daehoon; Zurita-Lopez, Cecilia; Kelly, Ryan; Guo, Ailan; Li, Wei; Clarke, Steven G.; Bedford, Mark T.

    2015-01-01

    The human genome encodes a family of nine protein arginine methyltransferases (PRMT1-9), which members can catalyze three distinct types of methylation on arginine residues. Here, we identify two spliceosome-associated proteins – SAP145 and SAP49 – as PRMT9 binding partners, linking PRMT9 to U2snRNP maturation. We show that SAP145 is methylated by PRMT9 at arginine 508, which takes the form of monomethylated arginine (MMA) and symmetrically dimethylated arginine (SDMA). PRMT9 thus joins PRMT5 as the only mammalian enzymes capable of depositing the SDMA mark. Methylation of SAP145 on Arg508 generates a binding site for the Tudor domain of the Survival of Motor Neuron (SMN) protein, and RNA-seq analysis reveals gross splicing changes when PRMT9 levels are attenuated. These results identify PRMT9 as a non-histone methyltransferase that primes the U2snRNP for interaction with SMN. PMID:25737013

  2. 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

  3. TiCl4-promoted condensation of methyl acetoacetate, isobutyraldehyde, and indole: a theoretical and experimental study.

    PubMed

    Renzetti, Andrea; Marrone, Alessandro; Gérard, Stéphane; Sapi, Janos; Nakazawa, Hiroshi; Re, Nazzareno; Fontana, Antonella

    2015-04-14

    The mechanism of the TiCl4-promoted condensation of methyl acetoacetate, isobutyraldehyde, and indole was studied by a combination of theoretical and experimental techniques. The energy profile of plausible reaction paths was evaluated by DFT calculations, and various reaction intermediates were isolated or observed in solution by NMR spectroscopy. Theoretical and experimental results indicate that the reaction proceeds in three steps, all promoted by titanium: (1) formation of the enolate ion of methyl acetoacetate, (2) Knoevenagel condensation of the enolate ion and aldehyde, and (3) Michael addition of indole to the Knoevenagel adduct. The study sheds light on the role of titanium in the reaction, providing a mechanistic model for analogous reactions. PMID:25746215

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

    PubMed

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

    2015-07-16

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

  5. DNA methylation profiling using HpaII tiny fragment enrichment by ligation-mediated PCR (HELP).

    PubMed

    Suzuki, Masako; Greally, John M

    2010-11-01

    The HELP assay is a technique that allows genome-wide analysis of cytosine methylation. Here we describe the assay, its relative strengths and weaknesses, and the transition of the assay from a microarray to massively-parallel sequencing-based foundation. PMID:20434563

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

    NASA Astrophysics Data System (ADS)

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

    2013-01-01

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

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

    PubMed

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

    2015-01-01

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

  8. 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.

  9. 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.

  10. 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 ...

  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

    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...

  12. Bis(1-methyl­piperidinium) tetra­chlorido­cuprate(II)

    PubMed Central

    Reynolds, Bryan J.; Bond, Marcus R.

    2011-01-01

    The structure of the title compound, (C6H14N)2[CuCl4], consists of two inequivalent 1-methyl­piperidinium cations and a flattened tetra­hedral [CuCl4]2− anion. Each organic cation exhibits a chair conformation with the methyl group in the equatorial position. They are segregated into alternating layers parallel to (100) and stacked along [100]. The first cation is arranged in parallel stacks in a herringbone pattern with rows of [CuCl4]2− anions fitting between the stacks and with a Cl− ion directed into the inter­ior of the layer. The second organic cation forms distorted hcp layers that separate the other organic cation/[CuCl4]2− slabs. N—H⋯Cl hydrogen bonding between the cations and the anions consolidates the crystal packing. PMID:21754622

  13. Rhodium(II)-Catalyzed C-H Functionalization of Electron-Deficient Methyl Groups.

    PubMed

    Fu, Liangbing; Guptill, David M; Davies, Huw M L

    2016-05-11

    Enantioselective C-H functionalization of relatively electron-deficient methyl sites was achieved with the combination of 2,2,2-trichloroethyl aryldiazoacetates and tetrakis(triarylcyclopropanecarboxylate) dirhodium catalysts. The substrate scope of the transformation was relatively broad, and C-H functionalization products were furnished with excellent levels of enantioselectivity. As a strategic reaction, crotonate derivatives give 1,6-dicarbonyl compounds, which are useful for further diversification. PMID:27064173

  14. (Biphenyl-2-yl)bromidobis(2-methyl-tetra-hydro-furan-κO)magnesium(II).

    PubMed

    Nordschild, Simon; Wohlgemuth, D; Bolte, Michael

    2009-01-01

    In the title Grignard reagent, [MgBr(C(12)H(9))(C(5)H(10)O)(2)], the Mg centre adopts a distorted tetra-hedral MgCO(2)Br arrangement. The dihedral angle between the two aromatic rings of the biphenyl residue is 44.00 (14)°. Each mol-ecule incorporates one R- and one S-configured 2-methyl-tetra-hydro-furan mol-ecule. PMID:21583743

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

    PubMed Central

    2012-01-01

    Background 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. Results 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. Conclusions 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

  16. 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.

  17. 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 percent were…

  18. 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.

  19. 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

  20. Spectroscopic characterization of copper(II) complexes of indoxyl N(4)-methyl thiosemicarbazone

    NASA Astrophysics Data System (ADS)

    Chandra, Sulekh; Kumar, Umendra

    2004-10-01

    New copper(II) complexes of indoxyl thiosemicarbazone (ITSC) of general composition CuL 2X 2 (where L: ITSC; X: Cl -, NO 3-, ClO 4-, NCS -) have been synthesized and characterized by elemental analysis, molar conductance, magnetic susceptibility measurements and spectral (electronic, IR, EPR, 1H NMR , Mass) studies. Cyclic voltammetry measurements show quasi-reversible Cu 2+/Cu 1+ couple. Various physico-chemical techniques suggest a tetragonal structure for these copper(II) complexes.

  1. Photochemistry of compounds adsorbed into cellulose—II. Methyl viologen redox reactions

    NASA Astrophysics Data System (ADS)

    Milosavljevic, B. H.; Thomas, J. K.

    Photoinduced reactions of methyl viologen MV 2+ in cellophane, have been studied by steady state and pulsed laser techniques. The reduced form MV + is produced on irradiation, due to e - abstraction from cellophane. The reduced form is quite stable for hours in aerated cellophane, unlike similar studies in water or alcohols. Small amounts of H 2O reduce the reactivity of MV 2+ and cellophane, and promote the formation of MV +/MV 2+ complex. These data are discussed, and their relevance to the bio-activity of MV 2+ indicated.

  2. DNA binding, DNA cleavage, antioxidant and cytotoxicity studies on ruthenium(II) complexes of benzaldehyde 4-methyl-3-thiosemicarbazones

    NASA Astrophysics Data System (ADS)

    Sampath, Krishnan; Sathiyaraj, Subbaiyan; Jayabalakrishnan, Chinnasamy

    2013-03-01

    Four new ruthenium(II) complexes with N(4)-methyl thiosemicarbazone ligands, (E)-2-(2-chlorobenzylidene)-N-methylhydrazinecarbothioamide (HL1) and (E)-N-methyl-2-(2-nitrobenzylidene)hydrazinecarbothioamide (HL2), were prepared and fully characterized by various spectro-analytical techniques. The Schiff bases act as bidentate, monobasic chelating ligands with S and N as the donor sites and are preferably found in the thiol form in all the complexes studied. The molecular structure of HL1 and HL2 were determined by single crystal X-ray diffraction method. DNA binding of the compounds was investigated by absorption spectroscopy which indicated that the complexes bind to DNA via intercalation. The oxidative cleavage of the complexes with CT-DNA inferred that the effects of cleavage are dose dependent. Antioxidant studies of the ligands and complexes showed the significant antioxidant activity against DPPH radical. In addition, the in vitro cytotoxicity of the ligands and complexes against MCF-7 cell line was assayed which showed higher cytotoxic activity with the lower IC50 values indicating their efficiency in killing the cancer cells even at low concentrations.

  3. Mononuclear and Dinuclear Manganese(II) Complexes from the Use of Methyl(2-pyridyl)ketone Oxime

    PubMed Central

    Efthymiou, Constantinos G.; Nastopoulos, Vassilios; Raptopoulou, Catherine; Tasiopoulos, Anastasios; Perlepes, Spyros P.; Papatriantafyllopoulou, Constantina

    2010-01-01

    The reactions of methyl(2-pyridyl)ketone oxime, (py)C(Me)NOH, with manganese(II) sulfate monohydrate have been investigated. The reaction between equimolar quantities of MnSO4 · H2O and (py)C(Me)NOH in H2O lead to the dinuclear complex [Mn2(SO4)2{(py)C(Me)NOH}4] · (py)C(Me)NOH, 1 · (py)C(Me)NOH, while employment of NaOMe as base affords the compound [Mn(HCO2)2{(py)C(Me)NOH}2] (2). The structures of both compounds have been determined by single crystal X-ray diffraction. In both complexes, the organic ligand chelates through its nitrogen atoms. The IR data are discussed in terms of the nature of bonding and the structures of the two complexes. PMID:20671965

  4. 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.

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

    PubMed

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

    2016-04-20

    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, χg. Depending on concentration and cooling rates, cooling leads to samples containing amorphous ice (χg ≥ 0.20), ice (χg ≤ 0.32), and/or "distorted ice" (0 < χg ≤ 0.38). Upon compression, we find that (a) fully vitrified samples at χg ≥ 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 χg ≈ 0.32 (T = 77 K). This is rather surprising since it has been known that at χg < 0.38, cooling leads to phase-separated samples with ice and maximally freeze-concentrated solution of χg ≈ 0.38. Accordingly, in the range 0.32 < χg < 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 χg ≤ 0.15, the water domains within the sample exhibit polyamorphism, i.e., the HDA-to-LDA (low-density amorphous ice) transformation. At 0.15 < χg ≤ 0.38, samples contain ice, interfacial ice, and/or HDA domains. All samples (χg ≤ 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 of glassy binary

  6. 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

  7. Crystal structure of tri­aqua­(2,6-di­methyl­pyrazine-κN 4)bis­(thio­cyanato-κN)manganese(II) 2,5-di­methyl­pyrazine disolvate

    PubMed Central

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

    2015-01-01

    In the crystal structure of the title complex, [Mn(NCS)2(C6H8N2)(H2O)3]·2C6H8N2, the MnII cation is coordinated by two terminally N-bonded thio­cyanate anions, three water mol­ecules and one 2,6-di­methyl­pyrazine ligand within a slightly distorted N3O3 octa­hedral geometry; the entire complex mol­ecule is generated by the application of a twofold rotation axis. The asymmetric unit also contains an uncoordinating 2,5-di­methyl­pyrazine ligand in a general position. Obviously, the coordination to the 2,6-di­methyl­pyrazine ligand is preferred because coordination to the 2,5-di­methyl­pyrazine 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-di­methyl­pyzazine/2,5-di­methyl­pyza­zine) hydrogen bonding, forming a three-dimensional network. In the crystal, mol­ecules are arranged in a way that cavities are formed in which unspecified, disordered solvent molecules reside. These were modelled employing the SQUEEZE routine in PLATON [Spek (2015 ▸). Acta Cryst. C71, 9–18]. The composition of the unit cell does not take into account the presence of the unspecified solvent. PMID:26870435

  8. Bis[μ-N-(tert-butyl­dimethyl­silyl)-N-(pyridin-2-ylmeth­yl)amido]­bis­[methyl­cobalt(II)

    PubMed Central

    Malassa, Astrid; Agthe, Christine; Görls, Helmar; Westerhausen, Matthias

    2012-01-01

    The green title complex, [Co2(CH3)2(C12H21N2Si)2], was obtained from bis­{[μ-N-tert-butyl­dimethyl­silyl-N-(pyridin-2-ylmeth­yl)amido]­chloridocobalt(II)} and methyl­lithium in diethyl ether at 195 K via a metathesis reaction. The dimeric cobalt(II) complex exhibits a crystallographic center of inversion in the middle of the Co2N2 ring (average Co—N = 2.050 Å). The CoII atom shows a distorted tetra­hedral coordination sphere. The exocyclic Co—N bond length to the pyridyl group shows a similar value of 2.045 (4) Å. The exocyclic methyl group has a rather long Co—C bond length of 2.019 (5) Å. PMID:22969464

  9. Fate and biological effects of methyl parathion in outdoor ponds and laboratory aquaria. II. Effects.

    PubMed

    Crossland, N O

    1984-10-01

    Methyl parathion (MEP) applied to three outdoor ponds at a nominal concentration of 100 micrograms liter-1 was toxic to some species of aquatic insects and crustaceans but not to fish. The spectrum of toxicity was similar to predictions based on a literature survey of data obtained from laboratory tests. Various secondary effects occurred that could not be predicted from laboratory toxicity tests. An increase in populations of Diaptomus in treated ponds was probably caused by mortality of predators and competitors. A bloom of filamentous algae which then collapsed, leading to severe depletion of dissolved oxygen and fish deaths, may have been triggered by mortality of herbivorous mayflies and daphnids. The growth of juvenile rainbow trout in treated ponds was significantly less than in untreated ponds. On the other hand their growth in laboratory aquaria was not affected when rainbow trout were exposed to higher concentrations of MEP than occurred in the outdoor ponds. It was concluded that growth of rainbow trout in the ponds was probably affected by mortality among aquatic insects and crustaceans on which they feed. PMID:6489243

  10. 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.

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

    PubMed Central

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

    2014-01-01

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

  12. Optimization of benzoyl peroxide concentration in an experimental bone cement based on poly(methyl methacrylate).

    PubMed

    Vazquez, B; Deb, S; Bonfield, W

    1997-07-01

    The effect of the concentration of benzoyl peroxide in poly(methyl methacrylate) bone cement formulations on their setting characteristics, particularly peak temperature and setting time, were studied. An optimization of the concentration of benzoyl peroxide was made with respect to curing parameters and compared with the residual monomer content. The mechanical properties of the different formulations were also determined and the results indicated that a composition of 1.5% wt/wt and 0.82% wt/wt of benzoyl peroxide and N,N-dimethyl-p-toluidine concentrations, respectively, gave the highest yield strength. Studies on the preparation of bone cement formulations containing different amounts of barium sulphate were also performed to assess the effect on the polymerization process and mechanical properties of the cements. PMID:15348730

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

    NASA Astrophysics Data System (ADS)

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

    2016-01-01

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

  14. 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. PMID:23963250

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

    PubMed

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

    2015-09-01

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

  16. 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

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

    PubMed

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

    2016-08-01

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

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

    PubMed

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

    2015-07-01

    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

  19. 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.

  20. 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.

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

    PubMed Central

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

    2013-01-01

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

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

    SciTech Connect

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

    1982-05-01

    Operating experience at EBR-II over the past 17 years has shown that a sodium-cooled pool-type reactor can be safely and efficiently operated and maintained. The reactor has performed predictably and benignly during normal operation and during both unplanned and planned plant upsets. The duplex-tube evaporators and superheaters have never experienced a sodium/water leak, and the rest of the steam-generating system has operated without incident. There has been no noticeable degradation of the heat transfer efficiency of the evaporators and superheaters, except for the one superheater replaced in 1981. There has been no need to perform any chemical cleaning of steam-system components. Operation of EBR-II has produced a wealth of information. As an irradiation facility, EBR-II has generated specific information on the behavior of oxide, carbide, and metallic fuels. As an LMFBR power plant, EBR-II has produced general information related to plant-systems and equipment design, plant safety, plant availability, and plant maintenance.

  3. 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.

  4. 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.

  5. Selective copper(II)-mediated oxidative coupling of a nucleophilic reagent to the para-methyl group of 2,4,6-trimethylphenol.

    PubMed

    Boldron, Christophe; Ozalp-Yaman, Seniz; Gamez, Patrick; Tooke, Duncan M; Spek, Anthony L; Reedijk, Jan

    2005-11-01

    A copper(II) neocuproine system has been developed for the efficient and very selective 1,6-addition of a nucleophile to the para-methyl group of 2,4,6-trimethylphenol. Crystallographic and spectroscopic data point towards the involvement of a micro-methoxo-micro-phenoxo-bridged copper species which appears to generate a highly reactive quinone methide intermediate that can be attacked by a nucleophilic reagent. PMID:16234935

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

    PubMed Central

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

    2016-01-01

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

  7. 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.

  8. 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.

  9. 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

  10. Preconcentration of Cu(II), Fe(III) and Pb(II) with 2-((2-aminoethylamino)methyl)phenol-functionalized activated carbon followed by ICP-OES determination.

    PubMed

    He, Qun; Hu, Zheng; Jiang, Yin; Chang, Xijun; Tu, Zhifeng; Zhang, Lina

    2010-03-15

    A procedure for separation and preconcentration trace amount of Cu(II), Fe(III) and Pb(II) by 2-((2-aminoethylamino)methyl)phenol-functionalized activated carbon (AC-AMP) packed column has been proposed. Under the optimized conditions (pH 4, flow rate 2.0 mL min(-1)), Cu(II), Fe(III) and Pb(II) were retained on the column, then quantitatively eluted by 2 mL 1 mol L(-1) nitric acid solution and determined by inductively coupled plasma-optical emission spectrometry (ICP-OES). The tolerance limits of electrolytes were very high. The adsorption capacity of AC-AMP was found to be 12.1, 67.1, and 16.2 mg g(-1) for Cu(II), Fe(III), and Pb(II), respectively. According to the definition of International Union of Pure and Applied Chemistry, the detection limits (3 sigma) of this method for Cu(II), Fe(III) and Pb(II) were 0.27, 0.41 and 0.16 microg L(-1), respectively. The relative standard deviation under optimum conditions is less than 3.0% (n=11). The proposed method has been validated by analyzing a certified reference material and successfully applied to the preconcentration and determination of Cu(II), Fe(III), and Pb(II) in actual samples with satisfactory results. PMID:19926213

  11. 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

  12. Dichlorido{N-[(5-methyl­thio­phen-2-yl)methyl­idene]-2-(pyridin-2-yl)ethanamine-κ2 N,N′}palladium(II)

    PubMed Central

    Radebe, Mduduzi P.; Onani, Martin O.; Motswainyana, William M.

    2013-01-01

    In the title compound, [PdCl2(C13H14N2S)], the PdII ion is coordinated by two N atoms of the chelating bidentate ligand and two chloride anions, giving rise to a distorted square-planar geometry. The methyl-substituted thio­phene arm and the pyridine ring are connected to the metal cation through N atoms to form a six-membered chelate ring with a boat conformation, making the complex stable. PMID:23476321

  13. Preparation and characterization of hydroxypropyl methyl cellulose films containing stable BCS Class II drug nanoparticles for pharmaceutical applications.

    PubMed

    Sievens-Figueroa, Lucas; Bhakay, Anagha; Jerez-Rozo, Jackeline I; Pandya, Natasha; Romañach, Rodolfo J; Michniak-Kohn, Bozena; Iqbal, Zafar; Bilgili, Ecevit; Davé, Rajesh N

    2012-02-28

    The design and feasibility of a simple process of incorporating stable nanoparticles into edible polymer films is demonstrated with the goal of enhancing the dissolution rate of poorly water soluble drugs. Nanosuspensions produced from wet stirred media milling (WSMM) were transformed into polymer films containing drug nanoparticles by mixing with a low molecular weight hydroxylpropyl methyl cellulose (HPMC E15LV) solution containing glycerin followed by film casting and drying. Three different BCS Class II drugs, naproxen (NPX), fenofibrate (FNB) and griseofulvin (GF) were studied. The influence of the drug molecule on the film properties was also investigated. It was shown that film processing methodology employed has no effect on the drug crystallinity according to X-ray diffraction (XRD) and Raman spectroscopy. Differences in aggregation behavior of APIs in films were observed through SEM and NIR chemical imaging analysis. NPX exhibited the strongest aggregation compared to the other drugs. The aggregation had a direct effect on drug content uniformity in the film. Mechanical properties of the film were also affected depending on the drug-polymer interaction. Due to strong hydrogen bonding with the polymer, NPX exhibited an increase in Young's Modulus (YM) of approximately 200%, among other mechanical properties, compared to GF films. A synergistic effect between surfactant/polymer and drug/polymer interactions in the FNB film resulted in an increase of more than 600% in YM compared to the GF film. The enhancement in drug dissolution rate of films due to the large surface area and smaller drug particle size was also demonstrated. PMID:22178619

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

    PubMed Central

    Onwudiwe, Damian C.; Ajibade, Peter A.

    2011-01-01

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

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

    PubMed Central

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

    2011-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2009-03-01

    The crystal structures of (μ-4,4’-bipyridyl)-di{nitrato-2,4-dibromo-6-[(2-hydroxyethylimino)methyl]phenolo (1-)copper} ( I), (μ-4,4’-bipyridyl)-di{nitrato-2,4-dichloro-6-[(2-hydroxyethylimino)methyl]phenolo(1-)copper} ( II), and (μ-4,4’-bipyridyl)-{4-chloro-2-[(2-hydroxyethylimino)methyl]phenolo(2-)copper-nitrato-4-chloro-2-[(2-hydroxyethylimino)methyl]phenolo(1-)copper} 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.

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

    SciTech Connect

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

    1982-01-01

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

  18. 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. PMID:27308055

  19. 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

  20. Role for the nuclear receptor-binding SET domain protein 1 (NSD1) methyltransferase in coordinating lysine 36 methylation at histone 3 with RNA polymerase II function

    PubMed Central

    Lucio-Eterovic, Agda Karina; Singh, Melissa M.; Gardner, Jeffrey E.; Veerappan, Chendhore S.; Rice, Judd C.; Carpenter, Phillip B.

    2010-01-01

    The NSD (nuclear receptor-binding SET domain protein) family encodes methyltransferases that are important in multiple aspects of development and disease. Perturbations in NSD family members can lead to Sotos syndrome and Wolf–Hirschhorn syndrome as well as cancers such as acute myeloid leukemia. Previous studies have implicated NSD1 (KMT3B) in transcription and methylation of histone H3 at lysine 36 (H3-K36), but its molecular mechanism in these processes remains largely unknown. Here we describe an NSD1 regulatory network in human cells. We show that NSD1 binds near various promoter elements and regulates multiple genes that appear to have a concerted role in various processes, such as cell growth/cancer, keratin biology, and bone morphogenesis. In particular, we show that NSD1 binding is concentrated upstream of gene targets such as the bone morphogenetic protein 4 (BMP4) and zinc finger protein 36 C3H type-like 1 (ZFP36L1/TPP). NSD1 regulates the levels of the various forms of methylation at H3-K36 primarily, but not exclusively, within the promoter proximal region occupied by NSD1. At BMP4 we find that this reduces the levels of RNAP II recruited to the promoter, suggesting a role for NSD1-dependent methylation in initiation. Interestingly, we also observe that the RNAP II molecules that lie within BMP4 have inappropriate persistence of serine-5 phosphorylation and reduced levels of serine-2 phosphorylation within the C-terminal domain (CTD) of the large subunit of RNAP II. Our findings indicate that NSD1 regulates RNAP II recruitment to BMP4, and failure to do so leads to reduced gene expression and abrogated levels of H3K36Me and CTD phosphorylation. PMID:20837538

  1. 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.

  2. 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.

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

    PubMed

    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 Ca(2+)-CaM, but no assignment of these features has been made. In addition, Ca(2+)-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 Ca(2+)-CaM. Density-modified electron-density maps enabled the accurate assignment of Ca(2+)-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 Ca(2+)-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 Ca(2+)-CaM in most of these structures. The adventitious binding of MPD helps to explain differences between the Ca(2+)-CaM crystal and solution structures and is likely to favor more open conformations of the EF-hands in the crystal. PMID:26894537

  4. Scram reliability under seismic conditions at the Experimental Breeder Reactor II

    SciTech Connect

    Roglans, J.; Wang, C.Y.; Hill, D.J.

    1993-08-01

    A Probabilistic Risk Assessment of the Experimental Breeder Reactor II has recently been completed. Seismic events are among the external initiating events included in the assessment. As part of the seismic PRA a detailed study has been performed of the ability to shutdown the reactor under seismic conditions. A comprehensive finite element model of the EBR-II control rod drive system has been used to analyze the control rod system response when subjected to input seismic accelerators. The results indicate the control rod drive system has a high seismic capacity. The estimated seismic fragility for the overall reactor shutdown system is dominated by the primary tank failure.

  5. Crystal structures of bis-ligand complexes of copper(II) with 2-[(2-hydroxyethylamino)-methyl]-4,6-dinitrophenol, 2,4-dichloro-6-[(2-hydroxyethylamino)-methyl]phenol, and 2,4-dibromo-6-[(2-hydroxyethylamino)-methyl]phenol

    SciTech Connect

    Chumakov, Yu. M. Tsapkov, V. I.; Bocelli, G.; Palomares-Sanchez, S. A.; Ortiz, R. S.; Gulea, A. P.

    2007-02-15

    The crystal structures of bis{l_brace}2,4-dibromo-6-[(2-hydroxyethylamino)-methyl]phenolato{r_brace}copper (I), bis{l_brace}2,4-dichloro-6-[(2-hydroxyethylamino)-methyl]phenolato{r_brace}copper (II), and bis{l_brace}2-[(2-hydroxyethylamino)-methyl]-4,6-dinitrophenolato{r_brace}copper (III) in which the metal atom is located at the center of symmetry are determined using X-ray diffraction. Crystals of compounds I and II are isostructural. The copper atom in the structures of compounds I and I coordinates two singly deprotonated bidentate molecules of the ligand through the phenol oxygen atoms and the azomethine nitrogen atoms with the formation of a distorted planar square. In the crystals, complexes I and II form one-dimensional infinite chains along the b axis. In the structure of compound III, the coordination polyhedron of the central atom is an elongated tetragonal bipyramid with the base formed by the azomethine nitrogen atoms and the phenol oxygen atoms. Both vertices of the bipyramid are occupied by the oxygen atoms of the amino alcohol groups of the neighboring complexes, which are related to the initial complex through the center of symmetry. In turn, the oxygen atoms of the alcohol groups of the initial complex are located at the vertices of the coordination bipyramids of the metal atoms of the neighboring centrosymmetric complexes, thus forming infinite polymer chains along the a axis.

  6. 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.

  7. Comparative analysis of the cytotoxicity of substituted [phenylglyoxal bis(4-methyl-3-thiosemicarbazone)] copper(II) chelates. 2. Parabolic correlations and their implications for selective toxicity.

    PubMed

    Coats, E A; Milstein, S R; Pleiss, M A; Roesener, J A

    1978-08-01

    The synthesis of an extended series of para-substituted [phenylglyoxal bis(4-methyl-3-thiosemicarbazone)] copper(II) chelates is reported. Subsequent biological evaluation and regression analysis have been performed, correlating pI50 with extrathermodynamic substituent parameters. Parabolic correlations with pi have resulted which predict optimum lipophilic character of the para substituent with respect to Ehrlich ascites cytotoxicity (pi0 = -2.13) and with respect to ascites vs. liver slice cytotoxicity (pi0 = -1.31). Results indicated clearly that the chelate most toxic to the tumor cell model may not be the most selective. PMID:691005

  8. (Acetato-κ2 O,O′)(acetato-κO)bis(2-amino-3-methyl­pyridine-κN 1)cobalt(II)

    PubMed Central

    Tadjarodi, Azadeh; Bijanzad, Keyvan; Notash, Behrouz

    2012-01-01

    In the title compound, [Co(CH3COO)2(C6H8N2)2], the CoII ion is five-coordinated by two pyridine N atoms from two 2-amino-3-methyl­pyridine ligands, two O atoms from one acetate ion and one O atom from another acetate ion in a distorted trigonal–bipyramidal geometry. The pyridine rings are nearly perpendicular to each other [dihedral angle = 84.49 (16)°]. The crystal packing is stabilized by intra­molecular and inter­molecular N—H⋯O hydrogen-bonding inter­actions. PMID:23125590

  9. 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.

  10. Canopy level emissions of 2-methyl-3-buten-2-ol, monoterpenes, and sesquiterpenes from an experimental Pinus taeda plantation.

    PubMed

    Geron, Christopher D; Daly, Ryan W; Arnts, Robert R; Guenther, Alex B; Mowry, Fred L

    2016-09-15

    Emissions of Biogenic Volatile Organic Compounds (BVOCs) observed during 2007 from an experimental Pinus taeda plantation in Central North Carolina are compared with model estimates from the Model of Emissions of Gases and Aerosols from Nature (MEGAN) version 2.1. Relaxed eddy accumulation (REA) estimates of 2-methyl-3-buten-2-ol (MBO) fluxes are a factor of 3-4 higher than MEGAN estimates. MEGAN monoterpene emission estimates were a factor of approximately two higher than REA flux measurements. MEGAN β-caryophyllene emission estimates were within 60% of growing season REA flux estimates but were several times higher than REA fluxes during cooler, dormant season periods. The sum of other sesquiterpene emissions estimated by MEGAN was several times higher than REA estimates throughout the year. Model components are examined to understand these discrepancies. Measured summertime leaf area index (LAI) (and therefore foliar biomass) is a factor of two higher than assumed in MEGAN for the P. taeda default. Increasing the canopy mean MBO emission factor from 0.35 to 1.0mgm(-2)h(-1) also reduces MEGAN vs. REA flux differences. This increase is within current MBO emission factor uncertainties. The algorithm within MEGAN which adjusts isoprene emission estimates as a function of the temperature and light of the previous 24h seems also to improve the seasonal MEGAN MBO correlation with REA fluxes. Including the effects of the previous 240h, however, seems to degrade temporal model correlation with fluxes. Monoterpene and sesquiterpene composition data from the REA are compared with MEGAN2.1 estimates and also branch enclosure and needle extract data collected at this site. To our knowledge, the flux data presented here are the first reported for MBO and sesquiterpenes from a P. taeda ecosystem. PMID:27232720

  11. 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. PMID:23860729

  12. 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).

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

    NASA Astrophysics Data System (ADS)

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

    2016-01-01

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

  14. Tissue-specific imprinting of the mouse insulin-like growth factor II receptor gene correlates with differential allele-specific DNA methylation.

    PubMed

    Hu, J F; Oruganti, H; Vu, T H; Hoffman, A R

    1998-02-01

    Imprinted genes may be expressed uniparentally in a tissue- and development-specific manner. The insulin-like growth factor II receptor gene (Igf2r), one of the first imprinted genes to be identified, is an attractive candidate for studying the molecular mechanism of genomic imprinting because it is transcribed monoallelically in the mouse but biallelically in humans. To identify the factors that control genomic imprinting, we examined allelic expression of Igf2r at different ages in interspecific mice. We found that Igf2r is not always monoallelically expressed. Paternal imprinting of Igf2r is maintained in peripheral tissues, including liver, kidney, heart, spleen, intestine, bladder, skin, bone, and skeletal muscle. However, in central nervous system (CNS), Igf2r is expressed from both parental alleles. Southern analysis of the Igf2r promoter (region 1) revealed that, outside of the CNS where Igf2r is monoallelically expressed, the suppressed paternal allele is fully methylated while the expressed maternal allele is completely unmethylated. In CNS, however, both parental alleles are unmethylated in region 1. The importance of DNA methylation in the maintenance of the genomic imprint was also confirmed by the finding that Igf2r imprinting was relaxed by 5-azacytidine treatment. The correlation between genomic imprinting and allelic Igf2r methylation in CNS and other tissues thus suggests that the epigenetic modification in the promoter region may function as one of the major factors in maintaining the monoallelic expression of Igf2r. PMID:9482664

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

    PubMed

    Tamang, Sem Raj; Hoefelmeyer, James D

    2015-01-01

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

  16. μ-(2,6-Bis{[3-(di-methyl-amino)-prop-yl]imino-meth-yl}-4-methyl-phenolato)-μ-hydroxido-bis-[(thio-cyanato-κN)copper(II)].

    PubMed

    Meera, M G; Selvaraj, P Kamatchi; Viswanathan, B; Ramkumar, V

    2013-01-01

    In the title compound, [Cu2(C19H31N4O)(OH)(NCS)2], the mol-ecular structure of the dinuclear complex reveals two penta-coordinated Cu(II) ions, which are bridged by the phenolate O atom of the ligand and by an exogenous hydroxide ion. The bridging atoms occupy equatorial positions in the coordination sphere of the metal atoms and complete the equatorial coordination planes with two ligand N atoms, the apical positions being occupied by thio-cyanate N atoms. The crystal structure also features π-π stacking inter-actions involving the benzene rings with a centroid-centroid distance of 3.764 (4)Å. The crystal studied was a non-merohedral twin, with a refined BASF value of 0.203 (2). PMID:24098174

  17. The Essential WD Repeat Protein Swd2 Has Dual Functions in RNA Polymerase II Transcription Termination and Lysine 4 Methylation of Histone H3

    PubMed Central

    Cheng, Hailing; He, Xiaoyuan; Moore, Claire

    2004-01-01

    Swd2, an essential WD repeat protein in Saccharomyces cerevisiae, is a component of two very different complexes: the cleavage and polyadenylation factor CPF and the Set1 methylase, which modifies lysine 4 of histone H3 (H3-K4). It was not known if Swd2 is important for the function of either of these entities. We show here that, in extract from cells depleted of Swd2, cleavage and polyadenylation of the mRNA precursor in vitro are completely normal. However, temperature-sensitive mutations or depletion of Swd2 causes termination defects in some genes transcribed by RNA polymerase II. Overexpression of Ref2, a protein previously implicated in snoRNA 3′ end formation and Swd2 recruitment to CPF, can rescue the growth and termination defects, indicating a functional interaction between the two proteins. Some swd2 mutations also significantly decrease global H3-K4 methylation and cause other phenotypes associated with loss of this chromatin modification, such as loss of telomere silencing, hydroxyurea sensitivity, and alterations in repression of INO1 transcription. Even though the two Swd2-containing complexes are both localized to actively transcribed genes, the allele specificities of swd2 defects suggest that the functions of Swd2 in mediating RNA polymerase II termination and H3-K4 methylation are not tightly coupled. PMID:15024081

  18. 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.

  19. Experimental Challenge to the vp-Process in Type II Supernovae

    NASA Astrophysics Data System (ADS)

    Kubono, S.

    2016-04-01

    The vp-process is a new nucleosynthetic scenario, proposed 2006, which supposed to take place at the very early epoch of type II supernova, involving nuclear reactions of proton-rich nuclei not only with protons and alphas, but also with neutrons due to the neutrino processes. The vp-process is one of the key processes for investigating the mechanism of type II supernovae, and the process could be possibly responsible for the anomalously abundant p-nuclei around mass 90-100. Specifically, the nuclear physics problems in the vp-process were discussed in this talk including our recent experimental results with low-energy RI beams and a simulation study. Alpha cluster resonances have been identified experimentally which play a crucial role for the stellar (α,p) and (α,γ) reactions just above the alpha threshold. Neutron induced reactions in the proton-rich nuclear regions in the vp-process are also suggested to play an important role, which will discard the waiting points, and accelerate the flow to heavier nuclei. This process involves nuclear structures of very high level density at high excitation energies in neutron deficient nuclei, and both of the projectile and the target are unstable, which is a quite difficult experimental challenge in nuclear astrophysics in the coming years. Some experimental challenges are discussed.

  20. 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.

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

    NASA Astrophysics Data System (ADS)

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

    1995-05-01

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

  2. 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.

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

    PubMed

    Conradie, Marrigje M; Conradie, Jeanet

    2011-08-28

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-05-01

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

  5. 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. PMID:17609560

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

    PubMed

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

    1986-02-01

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

  7. 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.

  8. 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. PMID:27135196

  9. 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.

    PubMed

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

    2014-12-10

    A series of heteroleptic copper(II) complexes of the type [CuL(1-4)(diimine)](ClO4)2 (1-8) [L(1-4)=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 [Formula: see text] 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. PMID:24998685

  10. Crystal structure of di­aqua­bis­(2,6-di­methyl­pyrazine-κN 4)bis­(thio­cyanato-κN)cobalt(II) 2,5-di­methyl­pyrazine monosolvate

    PubMed Central

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

    2015-01-01

    In the crystal structure of the title compound, [Co(NCS)2(C6H8N2)2(H2O)2]·C6H8N2, the CoII cation is coordinated by the N atoms of two terminal thio­cyanate anions, the O atoms of two water mol­ecules and two N atoms of two 2,6-di­methyl­pyrazine ligands. The coordination sphere of the resulting discrete complex is that of a slightly distorted octa­hedron. The asymmetric unit comprises a CoII cation and half of a 2,5-di­methyl­pyrazine ligand, both of which are located on centres of inversion, and a water ligand, a 2,6-di­­methyl­pyrazine ligand and one thio­cyanate 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-di­methyl­pyrazine solvent mol­ecules are located. The coordination of the 2,5-di­methyl­pyrazine mol­ecules 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-di­methyl­pyrazine 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-di­methyl­pyrazine ligands. The remaining water H atom is hydrogen bonded to one N atom of the 2,5-di­methyl­pyrazine solvent mol­ecule. This arrangement leads to the formation of a two-dimensional network extending parallel to (010). PMID:26870445

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

    SciTech Connect

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

    1992-12-01

    The human androgen-receptor gene (HUMARA; GenBank) contains a highly polymorphic trinucleotide repeat in the first exon. The authors have found that the methylation of HpaII and HhaI sites less than 100 pb 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, the authors examined X inactivation patterns in the B lymphocytes of potential and obligate carriers of X-linked agammaglobulinemia. 42 refs., 5 figs., 1 tab.

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

    PubMed Central

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

    2014-01-01

    Methylated histones H3K9 and H3K27 are canonical epigenetic silencing modifications in metazoan organisms, but the relationship between the two modifications has not been well characterized. H3K9me3 coexists with H3K27me3 in pluripotent and differentiated cells. However, we find that the functioning of H3K9me3 is altered by H3S10 phosphorylation in differentiated postmitotic osteoblasts and cycling B cells. Deposition of H3K9me3/S10ph at silent genes is partially mediated by the mitogen- and stress-activated kinases (MSK1/2) and the Aurora B kinase. Acquisition of H3K9me3/S10ph during differentiation correlates with loss of paused S5 phosphorylated RNA polymerase II, which is present on Polycomb-regulated genes in embryonic stem cells. Reduction of the levels of H3K9me3/S10ph by kinase inhibition results in increased binding of RNAPIIS5ph and the H3K27 methyltransferase Ezh1 at silent promoters. Our results provide evidence of a novel developmentally regulated methyl-phospho switch that modulates Polycomb regulation in differentiated cells and stabilizes repressed states. PMID:24430871

  13. catena-Poly[[dichloridomercury(II)]-μ-{N-[(E)-pyridin-2-yl­methyl­idene-κN]pyridin-3-amine-κ2 N 1:N 3}

    PubMed Central

    Mahmoudi, Ali; Dehghanpour, Saeed; Najafi, Leila; Khalafbeigi, Mohammad

    2012-01-01

    In the title coordination polymer, [HgCl2(C11H9N3)]n, the HgII ion is coordinated by three N atoms from two N-[(E)-pyridin-2-yl­methyl­idene]pyridin-3-amine (L) ligands and two chloride anions in a distorted trigonal–bipyramidal geometry. The two pyridine rings in L form a dihedral angle of 50.0 (2)°. L ligands bridge adjacent HgCl2 units into polymeric chains propagating in [010]. The crystal packing is further stabilized by weak inter­molecular C—H⋯Cl hydrogen bonds and π–π inter­actions between the pyridine rings, with a centroid–centroid separation of 3.529 (9) Å. PMID:23125577

  14. 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

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

    PubMed Central

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

    2014-01-01

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

  16. 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

  17. 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.

  18. 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.

  19. 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...

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

    PubMed

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

    2010-08-01

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

  1. 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.

    PubMed

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

    2015-03-15

    Mononuclear and binuclear copper(II) complexes of 2-benzoylpyridine-N(4)-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)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 d(x2-y2) ground state. The thermal stabilities of some of the complexes were also determined. PMID:25546494

  2. 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.

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

    PubMed Central

    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. PMID:26727467

  4. 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.

  5. 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

  6. 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

  7. 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.

  8. Statistical analysis of duplex-tube performance in Experimental Breeder Reactor II superheater SU-712

    SciTech Connect

    Gross, K.C.; Seidel, B.R.

    1986-06-01

    A detailed investigation was made of historical data recorded at Experimental Breeder Reactor II during operation with superheater SU-712. The objective of this study was to analyze and characterize the performance of 72 duplex steam tubes that became unbonded during a long period of operation. The information processing system ANALYZE was developed to perform the required numerical manipulations, statistical analyses, and correlation analyses with a large data base containing some five million data values. The ANALYZE system was successfully employed (a) to characterize the performance of all the steam tubes in terms of frequency and relative severity of unbonding, and (b) to establish a correlation between the observed anomalous behavior of the superheater and its operating parameters. Results from this investigation were used to select sections for materials examinations and physical tests that were performed after SU-712 was removed from operation.

  9. 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)

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

    NASA Astrophysics Data System (ADS)

    Surzhikov, S. T.

    2015-10-01

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

  11. Absence of nonhematopoietic MHC class II expression protects mice from experimental autoimmune myocarditis.

    PubMed

    Thelemann, Christoph; Haller, Sergio; Blyszczuk, Przemyslaw; Kania, Gabriela; Rosa, Muriel; Eriksson, Urs; Rotman, Samuel; Reith, Walter; Acha-Orbea, Hans

    2016-03-01

    Experimental autoimmune myocarditis (EAM) is a CD4(+) T-cell-mediated model of human inflammatory dilated cardiomyopathies. Heart-specific CD4(+) T-cell activation is dependent on autoantigens presented by MHC class II (MHCII) molecules expressed on professional APCs. In this study, we addressed the role of inflammation-induced MHCII expression by cardiac nonhematopoietic cells on EAM development. EAM was induced in susceptible mice lacking inducible expression of MHCII molecules on all nonhematopoietic cells (pIV-/- K14 class II transactivator (CIITA) transgenic (Tg) mice) by immunization with α-myosin heavy chain peptide in CFA. Lack of inducible nonhematopoietic MHCII expression in pIV-/- K14 CIITA Tg mice conferred EAM resistance. In contrast, cardiac pathology was induced in WT and heterozygous mice, and correlated with elevated cardiac endothelial MHCII expression. Control mice with myocarditis displayed an increase in infiltrating CD4(+) T cells and in expression of IFN-γ, which is the major driver of nonhematopoietic MHCII expression. Mechanistically, IFN-γ neutralization in WT mice shortly before disease onset resulted in reduced cardiac MHCII expression and pathology. These findings reveal a previously overlooked contribution of IFN-γ to induce endothelial MHCII expression in the heart and to progress cardiac pathology during myocarditis. PMID:26621778

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

    PubMed

    Yu, Shan-Shan; Zhang, Hui

    2016-08-01

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

  13. 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

  14. Ablation of peroxiredoxin II attenuates experimental colitis by increasing FoxO1-induced Foxp3+ regulatory T cells.

    PubMed

    Won, Hee Yeon; Jang, Eun Jung; Lee, Kihyun; Oh, Sera; Kim, Hyo Kyung; Woo, Hyun Ae; Kang, Sang Won; Yu, Dae-Yeul; Rhee, Sue-Goo; Hwang, Eun Sook

    2013-10-15

    Peroxiredoxin (Prx) II is an intracellular antioxidant molecule that eliminates hydrogen peroxide, employing a high substrate-binding affinity. PrxII deficiency increases the levels of intracellular reactive oxygen species in many types of cells, which may increase reactive oxygen species-mediated inflammation. In this study, we investigated the susceptibility of PrxII knockout (KO) mice to experimentally induced colitis and the effects of PrxII on the immune system. Wild-type mice displayed pronounced weight loss, high mortality, and colon shortening after dextran sulfate sodium administration, whereas colonic inflammation was significantly attenuated in PrxII KO mice. Although macrophages were hyperactivated in PrxII KO mice, the amount of IFN-γ and IL-17 produced by CD4(+) T cells was substantially reduced. Foxp3(+) regulatory T (Treg) cells were elevated, and Foxp3 protein expression was increased in the absence of PrxII in vitro and in vivo. Restoration of PrxII into KO cells suppressed the increased Foxp3 expression. Interestingly, endogenous PrxII was inactivated through hyperoxidation during Treg cell development. Furthermore, PrxII deficiency stabilized FoxO1 expression by reducing mouse double minute 2 homolog expression and subsequently activated FoxO1-mediated Foxp3 gene transcription. PrxII overexpression, in contrast, reduced FoxO1 and Foxp3 expression. More interestingly, adoptive transfer of naive CD4(+) T cells from PrxII KO mice into immune-deficient mice attenuated T cell-induced colitis, with a reduction in mouse double minute 2 homolog expression and an increase in FoxO1 and Foxp3 expression. These results suggest that inactivation of PrxII is important for the stability of FoxO1 protein, which subsequently mediates Foxp3(+) Treg cell development, thereby attenuating colonic inflammation. PMID:24048895

  15. 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

  16. Bis(di-methyl-formamide)-penta-kis-(μ-N,2-dioxido-benzene-1-carb-ox-imidato)tetra-kis-(1-methyl-imidazole)di-μ-propionato-penta-manganese(III)manganese(II)-di-methyl-formamide-methanol (1/0.24/1.36).

    PubMed

    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, shi(3-) is salicyl-hydroximate, Me-Im is 1-methyl-imidazole, DMF is N,N-di-methyl-formamide, and MeOH is methanol), contains an Mn(II) ion in the central cavity and five Mn(III) ions in the MC ring. The central Mn(II) 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 Mn(III) ions are six coordinate with distorted octa-hedral geometries. Two of the Mn(III) ions have Λ absolute stereoconfiguration, while the other two Mn(III) ions have a planar configuration. The fifth Mn(III) ion is five coordinate and has a distorted square pyramidal geometry with τ = 0.20. Three of the Mn(III) ions bind one 1-methyl-imidazole ligand. Two of the ring Mn(III) ions have a 1-methyl-imidazole and a DMF disordered over a coordination site. For one of the ring Mn(III) ions, the occupancy ratio of the ligands refines to 0.51 (1):0.49 (1) in favor of the DMF. For the other ring Mn(III) ion, the occupancy ratio of the ligands refines to 0.68 (1):0.32 (1) in favor of the 1-methyl-imidazole. Two propionate anions serve to bridge the central Mn(II) ion between two different Mn(III) 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 methyl-ene 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 mol-ecule. Furthermore, a methanol mol

  17. Crystal structure of di­aqua­bis­(2,6-di­methyl­pyrazine-κN)bis­(thio­cyanato-κN)cobalt(II) 2,5-di­methyl­pyrazine tris­olvate

    PubMed Central

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

    2015-01-01

    In the crystal structure of the title compound, [Co(NCS)2(C6H8N2)2(H2O)2]·3C6H8N2, the CoII cation is coordinated by two terminally N-bound thio­cyanate anions, two water mol­ecules and two 2,6-di­methyl­pyrazine ligands, forming a discrete complex with a slightly distorted octa­hedral N4O2 coordination environment. The asymmetric unit contains one CoII cation and three halves of 2,5-di­methyl­pyrazine solvate mol­ecules, all entities being completed by inversion symmetry, as well as one thio­cyanate anion, an aqua ligand and a 2,6-di­methyl­pyrazine ligand, all in general positions. In the crystal, discrete complexes are arranged in a way that cavities are formed where the noncoordinating 2,5-di­methyl­pyrazine mol­ecules 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-di­methyl­pyrazine ligands. The complex mol­ecules are linked by O—H⋯N hydrogen bonds between the water H atoms and the N atoms of 2,5-di­methyl­pyrazine solvent mol­ecules, leading to a layered structure extending parallel to (100). PMID:26870459

  18. 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.

  19. μ3-Acetato-μ2-acetato-(di-methyl-form-amide)-penta-kis-(μ-N,2-dioxido-benzene-1-carboximidato)penta-kis-(1-methyl-1H-imidazole)-penta-manganese(III)manganese(II)-diethyl ether-di-methyl-formamide-methanol-water (1/1/1/1/0.49).

    PubMed

    Tigyer, Benjamin R; Zeller, Matthias; Zaleski, Curtis M

    2013-01-01

    The title compound, [Mn6(C7H4NO3)5(CH3CO2)2(C4H6N2)4.62(C3H7NO)1.38]·(C2H5)2O·C3H7NO·CH3OH·0.49H2O or Mn(II)(OAc)2[15-MCMn(III)N(shi)-5](Me-Im)4.62(DMF)1.38·diethyl ether·DMF·MeOH·0.49H2O (where MC is metallacrown, (-)OAc is acetate, shi(3-) is salicyl-hydroximate, Me-Im is 1-methyl-imidazole, DMF is N,N-di-methyl-formamide, and MeOH is methanol), is comprised of five Mn(III) ions in the metallacrown ring and an Mn(II) ion which is encapsulated in the central cavity. Four of the ring Mn(III) ions are six-coordinate with distorted octa-hedral geometries. Two of these Mn(III) ions have a planar configuration, while the other two Mn(III) have Λ absolute stereoconfiguration. The fifth Mn(III) is five-coordinated with distorted square-pyramidal geometry. Four of the ring Mn(III) ions each bind one 1-methyl-imidazole, while the final ring Mn(III) ion binds a DMF solvent mol-ecule in an axial position and located in a trans position is either a Me-Im or a DMF mol-ecule. The occupancy ratio of Me-Im to DMF is 0.62 (2) to 0.38 (2). The central Mn(II) is seven-coordinate with a geometry best described as distorted face-capped trigonal-prismatic. DMF, diethyl ether, MeOH, and water mol-ecules are located in the inter-stitial voids between the metallacrown mol-ecules. The methanol mol-ecule is positionally disordered [0.51 (1):0.49 (1)] and associated with a partially occupied water mol-ecule [0.49 (1)]. This disorder is also associated with the positional disorder of the diethyl ether mol-ecule [0.51 (1):0.49 (1)]. PMID:24046568

  20. 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

  1. 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.

  2. 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.

  3. (2,2'-Bipyridyl-κN,N')bis-(N-butyl-N-methyl-dithio-carbamato-κS,S')cadmium(II).

    PubMed

    Jamaluddin, Nur Amirah; Baba, Ibrahim; Mohamed Tahir, Mohamed Ibrahim; Tiekink, Edward R T

    2011-01-01

    The Cd(II) atom in the title compound, [Cd(C(6)H(12)NS(2))(2)(C(10)H(8)N(2))], is hexa-coordinated by two dithio-carbamate ligands and the N atoms from a bidentate 2,2'-bipyridyl mol-ecule. The coordination geometry is based on a distorted trigonal-prismatic arrangement of the N(2)S(4) donor set. Supra-molecular chains, aligned along the a-axis direction, are mediated by C-H⋯S inter-actions and these are connected into layers that stack along the c axis via π-π inter-actions [Cg(pyrid-yl)⋯Cg(pyrid-yl) = 3.6587 (13) Å]. PMID:21522303

  4. Synthesis, structure, and optical properties of Pt(II) and Pd(II) complexes with oxazolyl- and pyridyl-functionalized DPPM-type ligands: a combined experimental and theoretical study.

    PubMed

    Zhang, Shuanming; Pattacini, Roberto; Braunstein, Pierre; De Cola, Luisa; Plummer, Edward; Mauro, Matteo; Gourlaouen, Christophe; Daniel, Chantal

    2014-12-15

    New square-planar complexes [Pt(1(-H))2] (2a) [1(-H) = (oxazolin-2-yl)bis(diphenylphosphino)methanide] and [Pd(1(-H))2] (2b), of general formula [M{(Ph2P)2C---C---NCH2CH2O}2] (M = Pt, 2a; M = Pd, 2b), result from deprotonation of 2-{bis(diphenylphosphino)methyl}oxazoline (1) at the PCHP site. The new, functionalized dppm-type ligand 4-{bis(diphenylphosphino)methyl}pyridine, (Ph2P)2CH(4-C5H4N) (4), was prepared by double lithiation and phosphorylation of 4-picoline. In the presence of NEt3, the reactions of 2 equiv of 4 with [PtCl2(NCPh)2] and [Pd(acac)2] (acac = acetylacetonate) afforded [Pt(4(-H))2] (5a) [4(-H) = bis(diphenylphosphino)(pyridin-4-yl)methanide] and [Pd(4(-H))2] (5b), of general formula [M{(Ph2P)2C(4-C5H4N)}2] (M = Pt, 5a; M = Pd, 5b), respectively. In the absence of base, the reactions of 2 equiv of 4 with [PtCl2(NCPh)2] and [PdCl2(NCPh)2] afforded (5a·2HCl) (6a) and (5b·2HCl) (6b), respectively, in which the PCHP proton of 4 has migrated from carbon to nitrogen to give a pyridinium derivative of general formula [M{(Ph2P)2C(4-C5H4NH)}2]Cl2 (M = Pt, 6a; M = Pd, 6b). The complexes 3a, 5a·2MeOH, and 6b·4CH2Cl2 have been structurally characterized by X-ray diffraction. The absorption/emission properties of the Pt(II) complexes 2a and 5a and the Pd(II) complexes 2b and 5b have been investigated by UV-vis spectroscopy and theoretical analysis based on density functional theory. The UV-vis absorption spectra of the neutral complexes recorded in dilute N,N'-dimethylformamide solutions are dominated by intense spin-allowed intraligand transitions in the region below 350 nm. The complexes exhibit charge-transfer bands between 350 and 500 nm. The experimental and theoretical absorption spectra agree qualitatively and point to two low-lying ligand-to-metal charge transfer states that contribute to the bands observed between 350 and 500 nm. The complexes are emissive in frozen solutions at 77 K, in the pure solid state, and when doped into films of poly(methyl

  5. LC-MS and GC-MS metabolite profiling of nickel(II) complexes in the latex of the nickel-hyperaccumulating tree Sebertia acuminata and identification of methylated aldaric acid as a new nickel(II) ligand.

    PubMed

    Callahan, Damien L; Roessner, Ute; Dumontet, Vincent; Perrier, Nicolas; Wedd, Anthony G; O'Hair, Richard A J; Baker, Alan J M; Kolev, Spas D

    2008-01-01

    Targeted liquid chromatography-mass spectrometry (LC-MS) technology using size exclusion chromatography and metabolite profiling based on gas chromatography-mass spectrometry (GC-MS) were used to study the nickel-rich latex of the hyperaccumulating tree Sebertia acuminata. More than 120 compounds were detected, 57 of these were subsequently identified. A methylated aldaric acid (2,4,5-trihydroxy-3-methoxy-1,6-hexan-dioic acid) was identified for the first time in biological extracts and its structure was confirmed by 1D and 2D nuclear magnetic resonance (NMR) spectroscopy. After citric acid, it appears to be one of the most abundant small organic molecules present in the latex studied. Nickel(II) complexes of stoichiometry NiII:acid=1:2 were detected for these two acids as well as for malic, itaconic, erythronic, galacturonic, tartaric, aconitic and saccharic acids. These results provide further evidence that organic acids may play an important role in the transport and possibly in the storage of metal ions in hyperaccumulating plants. PMID:17765935

  6. Theoretical and experimental investigation of (E)-2-([3,4-dimethylphenyl)imino]methyl)-3-methoxyphenol: Enol-keto tautomerism, spectroscopic properties, NLO, NBO and NPA analysis

    NASA Astrophysics Data System (ADS)

    Demircioğlu, Zeynep; Albayrak, Çiğdem; Büyükgüngör, Orhan

    2014-05-01

    The molecular structure and spectroscopic properties of (E)-2-([3,4-dimethylphenyl)imino]methyl)-3-methoxyphenol were investigated by X-ray diffraction, FT-IR and UV-vis spectroscopy. The vibrational frequencies calculatedusing DFT/B3LYP/6-31G(d,p) method. Results showed better agreement with the experimental values. The electronic properties was studied and the most prominent transition corresponds to π → π* and n → π*. Two types of intramolecular hydrogen bonds are strong OH⋯N interactions in enol-imine form and NH⋯O interactions in keto-amine form are compared by using density functional theory (DFT) method with B3LYP applying 6-31G(d,p) basis set. Both enol-keto tautomers engender six-membered ring due to intramolecular hydrogen bonded interactions.

  7. Sterically Demanding Multidentate Ligand Tris[(2-(6-methylpyridyl))methyl]amine Slows Exchange and Enhances Solution State Ligand Proton NMR Coupling to 199Hg(II)

    PubMed Central

    Bebout, Deborah C.; Bush, James F.; Crahan, Kathleen K.; Bowers, Edith V.; Butcher, Raymond J.

    2006-01-01

    The solution state coordination chemistry of Hg(ClO4)2 with tris[(2-(6-methylpyridyl))methyl]amine (TLA) was investigated in acetonitrile-d3 by proton NMR. Although Hg(II) is a d10 metal ion commonly associated with notoriously rapid exchange between coordination environments, as many as six ligand environments were observed to be in slow exchange on the chemical shift time scale at select metal-to-ligand ratios. One of these ligand environments was associated with extensive heteronuclear coupling between protons and 199Hg and was assigned to the complex [Hg(TLA)]2+. The 5J(1H199Hg) = 8 Hz associated with this complex is the first example of five-bond coupling in a nitrogen coordination compound of Hg(II). The spectral complexity of related studies conducted in acetone-d6 precluded analysis of coordination equilibria. Crystallographic characterization of the T-shaped complex [Hg(TLAH)(CH2COCH3)](ClO4)2 (1) in which two pyridyl rings are pendant suggested that the acidity of acetone combined with the poor coordinating abilities of the neutral solvent adds additional complexity to solution equilibria. The complex crystallizes in the triclinic space group P1¯ with a = 9.352(2) Å, b = 12.956(2) Å, c = 14.199(2) Å, α = 115.458(10)°, β = 90.286(11)°, γ = 108.445(11)°, and Z = 2. The HgNamine, Hg-Npyridyl, and Hg-C bond lengths in the complex are 2.614(4), 2.159(4), and 2.080(6) Å, respectively. Relevance to development of 199Hg NMR as a metallobioprobe is discussed. PMID:11978122

  8. Dynamics of Isolated 1,8-Naphthalimide and N-Methyl-1,8-naphthalimide: An Experimental and Computational Study.

    PubMed

    Gerbich, Thiemo; Schmitt, Hans-Christian; Fischer, Ingo; Mitrić, Roland; Petersen, Jens

    2016-04-01

    In this work we investigate the excited-state structure and dynamics of the two molecules 1,8-naphthalimide (NI) and N-methyl-1,8-naphthalimide (Me-NI) in the gas phase by picosecond time- and frequency-resolved multiphoton ionization spectroscopy. The energies of several electronically excited singlet and triplet states and the S1 vibrational wavenumbers were calculated. Nonadiabatic dynamics simulations support the analysis of the radiationless deactivation processes. The origin of the S1 ← S0 (ππ*) transition was found at 30 082 cm(-1) for NI and at 29 920 cm(-1) for Me-NI. Furthermore, a couple of low-lying vibrational bands were resolved in the spectra of both molecules. In the time-resolved scans a biexponential decay was apparent for both Me-NI and NI. The fast time constant is in the range of 10-20 ps, whereas the second one is in the nanosecond range. In accordance with the dynamics simulations, intersystem crossing to the fourth triplet state S1 (ππ*) → T4 (nπ*) is the main deactivation process for Me-NI due to a large spin-orbit coupling between these states. Only for significant vibrational excitation internal conversion via a conical intersection becomes a relevant deactivation pathway. PMID:26971952

  9. 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

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

    PubMed Central

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

    2009-01-01

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

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

    PubMed

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

    2012-06-01

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

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

    PubMed Central

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

    2008-01-01

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

  13. Bis(2-amino-4-methyl­pyridinium) trans-diaqua­bis­(pyrazine-2,3-dicarboxyl­ato)cuprate(II) hexa­hydrate

    PubMed Central

    Eshtiagh-Hosseini, Hossein; Gschwind, Fabienne; Alfi, Nafiseh; Mirzaei, Masoud

    2010-01-01

    The title compound, (C6H9N2)2[Cu(C6H2N2O4)2(H2O)2]·6H2O, consists of a mononuclear trans-[Cu(pzdc)2(H2O)2]2− dianion (pzdc is pyrazine-2,3-dicarboxyl­ate) and two [ampyH]+ cations (ampy is 2-amino-4-methyl­pyridine) with six water mol­ecules of solvation. The CuII atom is hexa­coordinated by two pzdc groups and two water mol­ecules. The coordinated water mol­ecules are in trans-diaxial positions and the pzdc dianion acts as a bidentate ligand through an O atom of the carboxyl­ate group and the N atom of the pyrazine ring. There are diverse hydrogen-bonding inter­actions, such as N—H⋯O and O—H⋯O contacts, which lead to the formation of a three-dimensional supra­molecular architecture. PMID:21587740

  14. Bis(2-amino-4-methyl-pyridinium) trans-diaqua-bis-(pyrazine-2,3-dicarboxyl-ato)cuprate(II) hexa-hydrate.

    PubMed

    Eshtiagh-Hosseini, Hossein; Gschwind, Fabienne; Alfi, Nafiseh; Mirzaei, Masoud

    2010-01-01

    The title compound, (C(6)H(9)N(2))(2)[Cu(C(6)H(2)N(2)O(4))(2)(H(2)O)(2)]·6H(2)O, consists of a mononuclear trans-[Cu(pzdc)(2)(H(2)O)(2)](2-) dianion (pzdc is pyrazine-2,3-dicarboxyl-ate) and two [ampyH](+) cations (ampy is 2-amino-4-methyl-pyridine) with six water mol-ecules of solvation. The Cu(II) atom is hexa-coordinated by two pzdc groups and two water mol-ecules. The coordinated water mol-ecules are in trans-diaxial positions and the pzdc dianion acts as a bidentate ligand through an O atom of the carboxyl-ate group and the N atom of the pyrazine ring. There are diverse hydrogen-bonding inter-actions, such as N-H⋯O and O-H⋯O contacts, which lead to the formation of a three-dimensional supra-molecular architecture. PMID:21587740

  15. 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.

  16. Syntheses, spectral, X-ray and DFT studies of 5-benzyl-N-phenyl-1,3,4-thiadiazol-2-amine, 2-(5-phenyl-1,3,4-thiadiazol-2-yl) pyridine and 2-(5-methyl-1,3,4-thiadiazole-2-ylthio)-5-methyl-1,3,4-thiadiazole obtained by Mn(II) catalyzed reactions

    NASA Astrophysics Data System (ADS)

    Dani, R. K.; Bharty, M. K.; Kushawaha, S. K.; Paswan, S.; Prakash, Om; Singh, Ranjan K.; Singh, N. K.

    2013-12-01

    New compounds 5-benzyl-N-phenyl-1,3,4-thiadiazol-2-amine (Bptha, 1), 2-(5-phenyl-1,3,4-thiadiazol-2-yl) pyridine (Pthp, 2) and 2-(5-methyl-1,3,4-thiadiazole-2-ylthio)-5-methyl-1,3,4-thiadiazole (Mtmth, 3) have been synthesized and characterized with the aid of elemental analyses, IR, NMR and single crystal X-ray data. The structure of compounds 1, 2 and 3 are stabilized via intramolecular as well as intermolecular hydrogen bonding and crystallize in monoclinic system with space group P 1, P21/n and P 1, respectively. During the course of reaction, the substituted thiosemicarbazide/thiohydrazide get cyclized into the corresponding thiadiazole in the presence of manganese(II) nitrate via loss of H2O to yield compounds 1 and 2. However condensation occurred in the case of 5-methyl-1,3,4-thiadiazole-2-thiol which yielded 2-(5-methyl-1,3,4-thiadiazole-2-ylthio)-5-methyl-1,3,4-thiadiazole (3) by loss of one mole of H2S from two moles of 5-methyl-1,3,4-thiadiazole-2-thiol in the presence of manganese(II) acetate. The geometry optimization has been performed using DFT method and geometrical parameters thus obtained for the compounds have been compared with their single crystal X-ray data. The negative values of HOMO and LUMO energies for the molecules indicate that they are stable. The electronic transition from the ground state to the excited state due to a transfer of electrons from the HOMO to LUMO levels is mainly associated with the π⋯π transition.

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

    ERIC Educational Resources Information Center

    Dweck, Carol S.; And Others

    1978-01-01

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

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

    SciTech Connect

    Ilas, Germina; Gauld, Ian C

    2011-01-01

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

  19. 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.

  20. 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

  1. 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.

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

    PubMed

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

    2016-06-30

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

  3. Crystal structure of cis,fac-{N,N-bis-[(pyridin-2-yl)meth-yl]methyl-amine-κ(3) N,N',N''}di-chlorido-(dimethyl sulfoxide-κS)ruthenium(II).

    PubMed

    Trotter, Kasey; Arulsamy, Navamoney; Hulley, Elliott

    2015-09-01

    The reaction of di-chlorido-tetra-kis-(dimethyl sulfoxide)-ruthen-ium(II) with N,N-bis[(pyridin-2-yl)meth-yl]methyl-amine aff-ords the title complex, [RuCl2(C13H15N3)(C2H6OS)]. The asymmetric unit contains a well-ordered complex mol-ecule. The N,N-bis-[(pyridin-2-yl)meth-yl]methyl-amine (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) Ru(II) 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 octa-hedral coordination geometry of the Ru(II) 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. Experimental designs for modeling retention patterns and separation efficiency in analysis of fatty acid methyl esters by gas chromatography-mass spectrometry.

    PubMed

    Skartland, Liv Kjersti; Mjøs, Svein A; Grung, Bjørn

    2011-09-23

    The retention behavior of components analyzed by chromatography varies with instrumental settings. Being able to predict how changes in these settings alter the elution pattern is useful, both with regards to component identification, as well as with regards to optimization of the chromatographic system. In this work, it is shown how experimental designs can be used for this purpose. Different experimental designs for response surface modeling of the separation of fatty acid methyl esters (FAME) as function of chromatographic conditions in GC have been evaluated. Full factorial, central composite, Doehlert and Box-Behnken designs were applied. A mixture of 38 FAMEs was separated on a polar cyanopropyl substituted polysilphenylene-siloxane phase capillary column. The temperature gradient, the start temperature of the gradient, and the carrier gas velocity were varied in the experiments. The modeled responses, as functions of chromatographic conditions, were retention time, retention indices, peak widths, separation efficiency and resolution between selected peak pairs. The designs that allowed inclusion of quadratic terms among the predictors performed significantly better than factorial design. Box-Behnken design provided the best results for prediction of retention, but the differences between the central composite, Doehlert and Box-Behnken designs were small. Retention indices could be modeled with much better accuracy than retention times. However, because the errors of predicted tR of closely eluting peaks were highly correlated, models of resolution (Rs) that were based on retention time had errors in the same range as corresponding models based on ECL. PMID:21851946

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

    PubMed

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

    2014-11-01

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

  6. 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.

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

    PubMed Central

    Held, Peter

    2015-01-01

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

  8. 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.

  9. 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…

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

    PubMed

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

    2016-11-01

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

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

    PubMed

    Yurdakul, Senay; Badoğlu, Serdar; Güleşci, Yeliz

    2015-02-25

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

  12. 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.

  13. 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.

  14. Methyl Iodide

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

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

    PubMed Central

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

    2015-01-01

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

  16. 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. PMID:27084942

  17. Horizontal transfer of DNA methylation patterns into bacterial chromosomes

    PubMed Central

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

    2016-01-01

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

  18. Methyl chloroform

    SciTech Connect

    Wray, T.K.

    1994-04-01

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

  19. 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)

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

    PubMed

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

    2016-06-24

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

  1. Experimental investigations of a proposed chromophore correlation model of self healing of Disperse Orange 11 doped in Poly(methyl methacrylate)

    NASA Astrophysics Data System (ADS)

    Ramini, Shiva Kumar

    We studied photodegradation and recovery of amplified spontaneous emission (ASE) in Disperse Orange 11 dye doped in Poly(methyl methacrylate)(PMMA) as a function of dye concentration and sample temperature. A simple chromophore correlation model is proposed to explain the self healing mechanism. Based on observations that the molecules are photoresistant at high dye concentration and low temperature, we propose that molecules form correlated regions that are resistant to damage and promote self-healing. We have developed a simple model for photodegradation and recovery that depends on three parameters: the intensity-dependent decay rate, the recovery rate, and the free energy advantage for a molecule being in a correlated group, which we call a domain. This model accounts for all observations of ASE and absorption spectroscopy of DO11 dye in PMMA as a function of time, pump intensity, and concentration during decay and recovery with one fixed set of theses three parameters. Furthermore, the theory predicts the behavior as a function of temperature, and is consistent with all experimental observations.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  3. Combined experimental and theoretical study on the reactivity of compounds I and II in horseradish peroxidase biomimetics.

    PubMed

    Ji, Li; Franke, Alicja; Brindell, Małgorzata; Oszajca, Maria; Zahl, Achim; van Eldik, Rudi

    2014-10-27

    For the exploration of the intrinsic reactivity of two key active species in the catalytic cycle of horseradish peroxidase (HRP), Compound I (HRP-I) and Compound II (HRP-II), we generated in situ [Fe(IV) O(TMP(+.) )(2-MeIm)](+) and [Fe(IV) O(TMP)(2-MeIm)](0) (TMP=5,10,15,20-tetramesitylporphyrin; 2-MeIm=2-methylimidazole) as biomimetics for HRP-I and HRP-II, respectively. Their catalytic activities in epoxidation, hydrogen abstraction, and heteroatom oxidation reactions were studied in acetonitrile at -15 °C by utilizing rapid-scan UV/Vis spectroscopy. Comparison of the second-order rate constants measured for the direct reactions of the HRP-I and HRP-II mimics with the selected substrates clearly confirmed the outstanding oxidizing capability of the HRP-I mimic, which is significantly higher than that of HRP-II. The experimental study was supported by computational modeling (DFT calculations) of the oxidation mechanism of the selected substrates with the involvement of quartet and doublet HRP-I mimics ((2,4) Cpd I) and the closed-shell triplet spin HRP-II model ((3) Cpd II) as oxidizing species. The significantly lower activation barriers calculated for the oxidation systems involving (2,4) Cpd I than those found for (3) Cpd II are in line with the much higher oxidizing efficiency of the HRP-I mimic proven in the experimental part of the study. In addition, the DFT calculations show that all three reaction types catalyzed by HRP-I occur on the doublet spin surface in an effectively concerted manner, whereas these reactions may proceed in a stepwise mechanism with the HRP-II mimic as oxidant. However, the high desaturation or oxygen rebound barriers during CH bond activation processes by the HRP-II mimic predict a sufficient lifetime for the substrate radical formed through hydrogen abstraction. Thus, the theoretical calculations suggest that the dissociation of the substrate radical may be a more favorable pathway than desaturation or

  4. 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.

  5. 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. PMID:10089287

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

    PubMed

    Uemura, Takeshi; Yamaguchi, Mao; Chatani, Naoto

    2016-02-24

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

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

    PubMed

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

    2012-02-21

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

  8. Inheritance of Cytosine Methylation.

    PubMed

    Tillo, Desiree; Mukherjee, Sanjit; Vinson, Charles

    2016-11-01

    There are numerous examples of parental transgenerational inheritance that is epigenetic. The informational molecules include RNA, chromatin modifications, and cytosine methylation. With advances in DNA sequencing technologies, the molecular and epigenetic mechanisms mediating these effects are now starting to be uncovered. This mini-review will highlight some of the examples of epigenetic inheritance, the establishment of cytosine methylation in sperm, and recent genomic studies linking sperm cytosine methylation to epigenetic effects on offspring. A recent paper examining changes in diet and sperm cytosine methylation from pools of eight animals each, found differences between a normal diet, a high fat diet, and a low protein diet. However, epivariation between individuals within a group was greater than the differences between groups obscuring any potential methylation changes linked to diet. Learning more about epivariation may help unravel the mechanisms that regulate cytosine methylation. In addition, other experimental and genetic systems may also produce more dramatic changes in the sperm methylome, making it easier to unravel potential transgenerational phenomena. J. Cell. Physiol. 231: 2346-2352, 2016. © 2016 Wiley Periodicals, Inc. PMID:26910768

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

    NASA Astrophysics Data System (ADS)

    Macit, Mustafa; Alpaslan, Gökhan

    2014-08-01

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

  10. 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.

  11. 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.

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

    PubMed

    Chen, Yiling; Dong, Hao; Zhang, Huichun

    2016-01-01

    A combined experimental-theoretical approach was taken to elucidate the reduction mechanisms of five representative aromatic N-oxides (ANOs) by Fe(II)-tiron complex and to identify the rate-limiting step. Based on the possible types of complexes formed with the reductant, three groups of ANOs were studied: type I refers to those forming 5-membered ring complexes through the N and O atoms on the side chain; type II refers to those forming 6-membered ring complexes through the N-oxide O atom and the O atom on the side chain; and type III refers to complexation through the N-oxide O atom only. Density functional theory calculations suggested that the elementary reactions, including protonation, N-O bond cleavage, and the second electron transfer processes, are barrierless, indicating that the first electron transfer is rate-limiting. Consistent with the theoretical results, the experimental solvent isotope effect, KIEH, for the reduction of quinoline N-oxide (a type III ANO) was obtained to be 1.072 ± 0.025, suggesting protonation was not involved in the rate-limiting step. The measured nitrogen kinetic isotope effect, KIEN, for the reduction of pyridine N-oxide (a type III ANO) (1.022 ± 0.006) is in good agreement with the calculated KIEN for its first electron transfer (1.011-1.028), confirming that the first electron transfer is rate-limiting. Electrochemical cell experiments demonstrated that the electron transfer process can be facilitated significantly by type I complexation with FeL2(6-) (1:2 Fe(II)-tiron complex), to some extent by type II complexation with free Fe(II), but not by weak type III complexation. PMID:26636617

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

    PubMed

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

    2016-04-01

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

  14. Role of angiotensin II in experimental Venezuelan equine encephalitis in rats.

    PubMed

    Bermúdez, John; Valero, Nereida; Mosquera, Jesús; Vargas, Renata; Hernández-Fonseca, Juan P; Quiroz, Yasmir; Godoy, Rosario

    2015-10-01

    Venezuelan equine encephalitis (VEE) is a viral disease transmitted by mosquitoes. The inflammation induced by the VEE virus is associated with a high mortality rate in mice. Angiotensin II (Ang II), a pro-inflammatory molecule, is produced in the normal rat brain. There is no information about the role of this molecule in the inflammatory events occurring during VEE and the effect of inflammation on the mortality rate in VEE-virus-infected rats. This study was designed to determine the role of Ang II in VEE and to analyze the effect of inflammation on mortality in infected rats. Two groups of rats were studied: 1) Virus-infected animals and controls (n = 60) were treated with losartan (a blocker of the Ang II-AT1 receptor) or with pyrrolidine dithiocarbamate (PDTC, an inhibitor of NF-κB) or left untreated and analyzed for morbidity and mortality. 2) Animals treated using the same protocol (n = 30) were sacrificed at day 4 postinfection and analyzed by immunohistochemistry and histopathology and for cytokine production. Increased expression of Ang II, ICAM-1, ED-1 and cytokines (IL-1α, MCP-1, IL-6 and IL-10) in infected animals was observed. The main histopathology findings were dilated capillaries and capillaries with endothelial detachment. Losartan and PDTC reduced the expression of IL-1α, MCP-1, and IL-10, and the number of dilated capillaries and capillaries with endothelial detachment. Survival analysis showed that 100% mortality was reached earlier in infected rats treated with losartan (day 14) or PDTC (day 11) than in untreated animals (day 19). These findings suggest that Ang II plays a role in VEE and that brain inflammation is protective against viral infection. PMID:26156105

  15. 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

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

    ERIC Educational Resources Information Center

    Harley, J. Preston; And Others

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

  17. 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

  18. 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)

  19. Effects of the novel anti-ulcer agent 1-(5'-oxohexyl)-3-methyl-7-propyl xanthine on experimental ulcers and gastric secretion in rats.

    PubMed

    Tanaka, T; Bickel, M; Herling, A W; Sakurai, M; Goto, M; Hayashi, S

    1989-06-01

    The effects of 1-(5'-oxohexyl)-3-methyl-7-propyl xanthine (HWA 285) on various experimentally induced ulcers and gastric acid secretion were investigated in rats. HWA 285 (10-50 mg/kg, p.o.) inhibited restraint and water-immersion-induced stress, ulcers, indometacin- and absolute ethanol-induced gastric ulcers and mepirizole-induced duodenal ulcers in rats in a dose-dependent manner. HWA 285 (10-25 mg/kg i.d.) had inhibitory effects on acetylsalicylic acid-induced ulcers. The healing of acetic acid-induced chronic ulcers was significantly accelerated by HWA 285 (25 mg/kg p.o.) when it was given twice daily for 7 consecutive days. When given orally (twice a day, 11 doses in total) before the induction of gastric ulcers by stress, cimetidine at 100 mg/kg aggravated the ulcers, whereas, HWA 285 at 25 mg/kg had not such an effect. In conscious pylorus-ligated rats, HWA 285 (10-100 mg/kg i.p.) showed a dose-dependent inhibition on basal and desglugastrin- and 2-deoxy-D-glucose (2-DG)-stimulated gastric acid secretion. In stomach-lumen perfused rats, HWA 285 (30 mg/kg i.v.) inhibited 2-DG-stimulated gastric acid secretion but not carbachol-stimulated gastric acid secretion. These results suggest that the anti-ulcer effects of HWA 285 are produced by cytoprotective and central anti-secretory activity without peripheral anti-cholinergic properties. Whether the central anti-secretory effects of HWA 285 play thereby the key role, have to be clarified in further investigation. PMID:2775336

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

    NASA Astrophysics Data System (ADS)

    Demircioğlu, Zeynep; Albayrak, Çiğdem; Büyükgüngör, Orhan

    2014-07-01

    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 Cdbnd N double bond. The compound adopts a enol-imine tautomeric form with a strong intramolecular Osbnd H⋯N hydrogen bond. The single crystal X-ray diffraction analysis at 296 K 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.

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

    NASA Astrophysics Data System (ADS)

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

    2011-12-01

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

  2. The effect of L-arginine methyl ester on indices of free radical involvement in a rat model of experimental nephrocalcinosis.

    PubMed

    Ozturk, Hayrettin; Ozturk, Hulya; Yagmur, Yusuf; Buyukbayram, Huseyin

    2006-10-01

    The aim of this study was to test the effect of L: -arginine methyl ester (L-Arg) on indices of free radical involvement in a rat model of experimental nephrocalcinosis. Twenty-eight Sprague-Dawley rats were randomized into four groups of seven. The first group (G1), the sham-control group received pure distilled drinking water. The second group (G2) received drinking water containing 0.7% ethylene glycol (EG) in distilled water for 3 weeks. The third group (G3) received drinking water containing 0.7% EG in distilled water for 3 weeks and L-Arg was administered for 3 weeks. The fourth group (G4) received drinking water containing 0.7% EG in distilled water for 3 weeks and L-NAME was administered for 3 weeks. Urine and aortic blood was collected to determine some parameters. The kidneys were also removed for histological examination. The increase in blood urea nitrogen, serum creatinine, K(+), Mg(2+ )and uric acid were mild in group 3 compared with the groups 2 and 4. The urinary concentrations of Na(+), K(+), Mg(2+) and uric acid were noticed to be similar among the groups. However, Ca(2+ )and oxalate excretion were significantly higher in groups 2, 3 and 4 than in group 1. The mean values of SOD, CAT and GSH-Px values were significantly increased in group 3 when compared to groups 2 and 4. Presence of aggregated urinary crystals was clearer in experimental groups compared to group 1. The tubular dilatation, epithelial degeneration and lymphocytic infiltration were significantly found in groups 2 and 4. Mild tissue damage was observed in L-Arg-pretreated rats. Under polarized light microscope intense crystals in the cortex and medulla were observed in the kidney of group 2 and 4 and moderate crystals were noticed in group 3. In conclusion, L-Arg supplementation may decrease free radicals and tubulary membrane injury in nephrocalcinosis due to infiltrating leukocytes and decreased antioxidant enzyme activities in rats fed with EG diet. PMID:16823549

  3. 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%. PMID:19577844

  4. 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

    2015-11-01

    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. PMID:26417689

  5. A novel Zn(II) complex of N-nicotinyl phosphoramide: Combined experimental and computational studies

    NASA Astrophysics Data System (ADS)

    Gholivand, Khodayar; Molaei, Foroogh; Thibonnet, Jérôme

    2015-07-01

    A novel Zn(II) coordination polymer of N-nicotinyl phosphoric triamide ligand, {[Zn(L)2(H2O)2]ṡ(NO3)2}n C1 (L = 3-NC5H4C(O)NHP(O)(NC6H12)2), has been synthesized and characterized by IR and 1H, 13C, 31P NMR spectroscopy. Crystal structure analysis of C1 demonstrates a distorted octahedral geometry for Zn(II) ions. The oxygen atom of phosphoryl group (Ophosphoryl) and the nitrogen atom of pyridine ring (Npyridine) of ligand take part in coordination to Zn(II) centers in a bidentate bridging mode. This coordination pattern results in infinite 1D polymeric chains along c axis, which are composed of metal shared 16-membered puckered rings. Structural data show that despite binding through Ophosphoryl, the Pdbnd O bond distance unexpectedly shortens in C1 when compared to that of the ligand, conceivably due to the steric factors in the solid state. This is confirmed by comparing the structural and electronic properties of C1 and L in the gas phase by using density functional theory (DFT) calculations. Natural bond orbital (NBO) analysis reveals the metal-ligand interaction for C1 as donor-acceptor type delocalizations (charge transfer). Besides, on the basis of the quantum theory of atoms in molecules (QTAIM) analysis, the nature of Znsbnd O and Znsbnd N bondings is found to be mainly electrostatic with a small amount of covalent character.

  6. Alumina-supported bimetallics of palladium alloyed with germanium, tin, lead, or antimony from organometallic precursors. II. Gas-phase hydrogenation of 2-methyl-1-buten-3-yne (valylene) and 2-methyl-1,3-butadiene (isoprene)

    SciTech Connect

    Aduriz, H.R.; Bodnariuk, P. ); Coq, B.; Figueras, F. )

    1991-05-01

    A series of PdGe, PdSb, PdSn, and PdPb/{alpha}{minus}Al{sub 2}O{sub 3} catalysts, prepared by the controlled surface reaction (CSR) technique from organometallic precursors have been tested in the gas-phase hydrogenation of 2-methyl-1-buten-3-yne (valylene) and 2-methyl-1,3-butadiene (isoprene). On catalysts reduced at 573 K, the turnover frequencies for valylene (TON{sub v}) and isoprene (TON{sub 1}) hydrogenation were not modified by addition to the 0.09wt% Pd/{alpha}{minus}Al{sub 2}O{sub 3} base catalyst of Ge, Sb, Sn, or Pb, up to0.1 wt% (at 293 K: TON{sub v}= 20 s{sup {minus}1} and TON{sub 1} = 33 s{sup {minus}1}). Pd/{alpha}{minus}Al{sub 2}O{sub 3} reduced at 773 K was severely sintered (d{sub TEM} increased from 2.8nm to 12.4nm) and TON{sub v} and TON{sub 1} at 293 K increased to 190 and 283 s{sup {minus}1}, respectively, as a result of an apparent crystal size effect: the reactants adsorb more strongly on the smaller Pd particles. Upon alloying with Ge, Sb, Sn, or Pb and a subsequent reduction at 773 K, a modest decrease of both TON{sub v} (by a factor of 2) and TON{sub 1} (by a factor of 2{minus}5) was observed. At high conversion, both the selectivity to isoprene (S{sub I}) in valylene hydrogenation, and to olefins (S{sub 0}) in isoprene hydrogenation on Pd/{alpha}{minus}Al{sub 2}O{sub 3} were improved upon alloying with Sb, Sn, or Pb (Ge had no effect). In addition, the isomerization of 2-methyl-1-butene and 3-methyl-1-butene (double bond migration reaction) during isoprene hydrogenation was partially suppressed on PdSn and PdPb/{alpha}{minus}Al{sub 2}O{sub 3}. The improvement in selectivities was interpreted in terms of a change in the relative adsorption strength of the reactants and intermediate products over the new bimetallic sites.

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

    NASA Astrophysics Data System (ADS)

    Huenecke, Klaus; Mertens, Josef

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

  8. 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

  9. 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

  10. Crystal structure of aqua-{μ-N-[3-(di-methyl-amino)-prop-yl]-N'-2-(oxidophen-yl)oxamidato}(1,10-phen-anthroline-5,6-dione)dicopper(II) perchlorate hemihydrate.

    PubMed

    Zhang, Xin; Li, Yan-Tuan; Wu, Zhi-Yong

    2015-06-01

    The title compound, [Cu2(C13H16N3O3)(C12H6N2O2)(H2O)]ClO4·0.5H2O, consists of a cis-oxamide-bridged binuclear Cu(II) complex cation, a perchlorate anion and half a solvent water mol-ecule. One Cu(II) cation is N,N',N",O-chelated by an N-[3-(di-methyl-amino)-prop-yl]-N'-(2-hy-droxy-phen-yl)oxamide trianion in a distorted square-planar geometry, whereas the other Cu(II) cation is O,O'-chelated by the oxamide moiety of the anion and N,N'-chelated by a 1,10-phenanthroline-5,6-dione mol-ecule, and a water mol-ecule further coordinates the second Cu(II) cation, completing a distorted square-pyramidal coordination geometry. In the crystal, classical O-H⋯O hydrogen bonds, weak C-H⋯O hydrogen-bonding inter-actions and π-π stacking inter-actions link the complex cations, anions and solvent water mol-ecules into a three-dimensional supra-molecular architecture. In the crystal, the di-methyl-amino-propyl unit of the oxamide anion is disordered over two positions with an occupancy ratio of 0.561 (11):0.439 (11); the solvent water mol-ecule is also disordered over two positions, the occupancy ratio being 0.207 (10):0.293 (10). PMID:26090146

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

    PubMed

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

    2016-06-01

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

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

    PubMed

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

    2011-09-01

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

  13. 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

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

    PubMed Central

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

    2008-01-01

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

  15. Genetic and epigenetic transgenerational implications related to omega-3 fatty acids. Part II: maternal FADS2 rs174575 genotype and DNA methylation predict toddler cognitive performance.

    PubMed

    Cheatham, Carol L; Lupu, Daniel S; Niculescu, Mihai D

    2015-11-01

    Maternal transfer of fatty acids is important to fetal brain development. The prenatal environment may differentially affect the substrates supporting declarative memory abilities, as the level of fatty acids transferred across the placenta may be affected by the maternal fatty acid desaturase 2 (FADS2) rs174575 single nucleotide polymorphism. In this study, we hypothesized that toddler and maternal rs174575 genotype and FADS2 promoter methylation would be related to the toddlers' declarative memory performance. Seventy-one 16-month-old toddlers participated in an imitation paradigm designed to test immediate and long-term declarative memory abilities. FADS2 rs174575 genotype was determined and FADS2 promoter methylation was quantified from blood by bisulfite pyrosequencing for the toddlers and their natural mothers. Toddlers of GG mothers at the FADS2 rs174575 single nucleotide polymorphism did not perform as well on memory assessments as toddlers of CC or CG mothers when controlling for plasma α-linolenic acid and child genotype. Toddler methylation status was related to immediate memory performance, whereas maternal methylation status was related to delayed memory performance. Thus, prenatal experience and maternal FADS2 status have a pervasive, long-lasting influence on the brain development of the offspring, but as the postnatal environment becomes more primary, the offsprings' own biology begins to have an effect. PMID:26455892

  16. 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. PMID:22183295

  17. 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

  18. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

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

    PubMed

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

    2016-07-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2004-11-01

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

  2. 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. PMID:25857375

  3. 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

  4. An integrated plant-life extension program for EBR-II (Experimental Breeder Reactor)

    SciTech Connect

    King, R.W.

    1986-01-01

    An integrated plant-life extension program is being developed and implemented at EBR-II. The program plan has five primary areas of focus, and is structured to take advantage of inherent features of the liquid-metal-cooled reactor that give it potential for very long life. The program is centered around development and increased use of computer-based software systems for surveillance, diagnostics, prognostics, data handling, and knowledge transfer. Even though the program is only partially implemented, benefits are already being realized in the form of increased understanding of plant system status and performance due to development of diagnostic data-handling software for manipulation of plant sensor data, and improved force monitoring and protection of the remotely operated fuel handling system. The eventual integration of the elements of the program is a key feature that is expected to enhance the overall effectiveness of the program.

  5. 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.

  6. 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.

  7. Experimental retinal branch vein occlusion in rhesus monkeys. II. Retinal blood flow studies.

    PubMed Central

    Rosen, D A; Marshall, J; Kohner, E M; Hamilton, A M; Dollery, C T

    1979-01-01

    Experimental branch vein occlusion by laser photocoagulation in the rhesus monkey leads to early, marked, and lasting reduction of blood flow to the affected retinal region. The radioactive microsphere method demonstrates this reduction of blood flow in both gamma counting and autoradiography. The reduction of flow becomes evident as early as 2 hours after occlusion and persists up to 1 week. The mechanism of the altered flow is discussed. PMID:111702

  8. Methyl chloride

    Integrated Risk Information System (IRIS)

    Methyl chloride ; CASRN 74 - 87 - 3 ( 07 / 17 / 2001 ) Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for

  9. 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

  10. 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

  11. 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

  12. 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

  13. 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

  14. Methyl methacrylate

    Integrated Risk Information System (IRIS)

    Methyl methacrylate ; CASRN 80 - 62 - 6 ( 03 / 02 / 98 ) Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments f

  15. 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.

  16. 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.

  17. Molecular dynamics simulation of liquid methanol. II. Unified assignment of infrared, raman, and sum frequency generation vibrational spectra in methyl C-H stretching region

    NASA Astrophysics Data System (ADS)

    Ishiyama, Tatsuya; Sokolov, Vladimir V.; Morita, Akihiro

    2011-01-01

    Vibrational spectra of methyl C-H stretching region are notoriously complicated, and thus a theoretical method of systematic assignment is strongly called for in condensed phase. Here we develop a unified analysis method of the vibrational spectra, such as infrared (IR), polarized and depolarized Raman, and ssp polarized sum frequency generation (SFG), by flexible and polarizable molecular dynamics simulation. The molecular model for methanol has been developed by charge response kernel model to allow for analyzing the methyl C-H stretching vibrations. The complicated spectral structure by the Fermi resonance has been unraveled by empirically shifting potential parameters, which provides clear information on the coupling mechanism. The analysis confirmed that for the IR, polarized Raman, and SFG spectra, two-band structure at about 2830 and 2950 cm^{-1} results from the Fermi resonance splitting of the methyl C-H symmetric stretching and bending overtones. In the IR spectrum, the latter, higher-frequency band is overlapped with prominent asymmetric C-H stretching bands. In the depolarized Raman spectrum, the high frequency band at about 2980 cm^{-1} is assigned to the asymmetric C-H stretching mode. In the SFG spectrum, the two bands of the splitted symmetric C-H stretching mode have negative amplitudes of imaginary nonlinear susceptibility χ ^{(2)}, while the higher-frequency band is partly cancelled by positive imaginary components of asymmetric C-H stretching modes.

  18. Molecular dynamics simulation of liquid methanol. II. Unified assignment of infrared, Raman, and sum frequency generation vibrational spectra in methyl C-H stretching region.

    PubMed

    Ishiyama, Tatsuya; Sokolov, Vladimir V; Morita, Akihiro

    2011-01-14

    Vibrational spectra of methyl C-H stretching region are notoriously complicated, and thus a theoretical method of systematic assignment is strongly called for in condensed phase. Here we develop a unified analysis method of the vibrational spectra, such as infrared (IR), polarized and depolarized Raman, and ssp polarized sum frequency generation (SFG), by flexible and polarizable molecular dynamics simulation. The molecular model for methanol has been developed by charge response kernel model to allow for analyzing the methyl C-H stretching vibrations. The complicated spectral structure by the Fermi resonance has been unraveled by empirically shifting potential parameters, which provides clear information on the coupling mechanism. The analysis confirmed that for the IR, polarized Raman, and SFG spectra, two-band structure at about 2830 and 2950 cm(-1) results from the Fermi resonance splitting of the methyl C-H symmetric stretching and bending overtones. In the IR spectrum, the latter, higher-frequency band is overlapped with prominent asymmetric C-H stretching bands. In the depolarized Raman spectrum, the high frequency band at about 2980 cm(-1) is assigned to the asymmetric C-H stretching mode. In the SFG spectrum, the two bands of the splitted symmetric C-H stretching mode have negative amplitudes of imaginary nonlinear susceptibility χ(2), while the higher-frequency band is partly cancelled by positive imaginary components of asymmetric C-H stretching modes. PMID:21241123

  19. 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.

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

    SciTech Connect

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

    1997-12-31

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

  1. Improvements to GALA and dbERGE II: databases featuring genomic sequence alignment, annotation and experimental results.

    PubMed

    Elnitski, Laura; Giardine, Belinda; Shah, Prachi; Zhang, Yi; Riemer, Cathy; Weirauch, Matthew; Burhans, Richard; Miller, Webb; Hardison, Ross C

    2005-01-01

    We describe improvements to two databases that give access to information on genomic sequence similarities, functional elements in DNA and experimental results that demonstrate those functions. GALA, the database of Genome ALignments and Annotations, is now a set of interlinked relational databases for five vertebrate species, human, chimpanzee, mouse, rat and chicken. For each species, GALA records pairwise and multiple sequence alignments, scores derived from those alignments that reflect the likelihood of being under purifying selection or being a regulatory element, and extensive annotations such as genes, gene expression patterns and transcription factor binding sites. The user interface supports simple and complex queries, including operations such as subtraction and intersections as well as clustering and finding elements in proximity to features. dbERGE II, the database of Experimental Results on Gene Expression, contains experimental data from a variety of functional assays. Both databases are now run on the DB2 database management system. Improved hardware and tuning has reduced response times and increased querying capacity, while simplified query interfaces will help direct new users through the querying process. Links are available at http://www.bx.psu.edu/. PMID:15608239

  2. Experimental verification of a tank to tank He II transfer model with trade study results

    NASA Technical Reports Server (NTRS)

    Yuan, S. W. K.; Frederking, T. H. K.

    1990-01-01

    A computer program has been developed to study the thermodynamics of tank to tank superfluid helium transfer. The model includes a supply and a receiver tank connected by a transfer line. The convey of He II from one tank to the other is controlled by a fountain effect pump (FEP). Phase separators are present in both the supply and receiver tank to regulate the bath temperature. Description of this model has been published elsewhere. In the present paper, data from a transfer experiment are used to verify the accuracy of this model. The experiment consisted of an FEP made of a 2-micron sintered stainless steel porous plug. Superfluid has been transferred from a liquid helium bath into a glass beaker. Bath temperatures, flowrate and heater power records are available. These results are compared to the predictions of the computer program and good agreement is found between the two. This model is very useful for the study and design of superfluid transfer systems, e.g., the Superfluid Helium Tanker (SFHT) and the Particle Astrophysics Magnet Facility (ASTROMAG).

  3. μ3-Acetato-μ2-acetato-(di­methyl­form­amide)­penta­kis­(μ-N,2-dioxido­benzene-1-carboximidato)penta­kis­(1-methyl-1H-imidazole)­penta­manganese(III)manganese(II)–diethyl ether–di­methyl­formamide–methanol–water (1/1/1/1/0.49)

    PubMed Central

    Tigyer, Benjamin R.; Zeller, Matthias; Zaleski, Curtis M.

    2013-01-01

    The title compound, [Mn6(C7H4NO3)5(CH3CO2)2(C4H6N2)4.62(C3H7NO)1.38]·(C2H5)2O·C3H7NO·CH3OH·0.49H2O or MnII(OAc)2[15-MCMn(III)N(shi)-5](Me—Im)4.62(DMF)1.38·diethyl ether·DMF·MeOH·0.49H2O (where MC is metallacrown, −OAc is acetate, shi3− is salicyl­hydroximate, Me—Im is 1-methyl­imidazole, DMF is N,N-di­methyl­formamide, and MeOH is methanol), is comprised of five MnIII ions in the metallacrown ring and an MnII ion which is encapsulated in the central cavity. Four of the ring MnIII ions are six-coordinate with distorted octa­hedral geometries. Two of these MnIII ions have a planar configuration, while the other two MnIII have Λ absolute stereoconfiguration. The fifth MnIII is five-coordinated with distorted square-pyramidal geometry. Four of the ring MnIII ions each bind one 1-methyl­imidazole, while the final ring MnIII ion binds a DMF solvent mol­ecule in an axial position and located in a trans position is either a Me—Im or a DMF mol­ecule. The occupancy ratio of Me—Im to DMF is 0.62 (2) to 0.38 (2). The central MnII is seven-coordinate with a geometry best described as distorted face-capped trigonal–prismatic. DMF, diethyl ether, MeOH, and water mol­ecules are located in the inter­stitial voids between the metallacrown mol­ecules. The methanol mol­ecule is positionally disordered [0.51 (1):0.49 (1)] and associated with a partially occupied water mol­ecule [0.49 (1)]. This disorder is also associated with the positional disorder of the diethyl ether mol­ecule [0.51 (1):0.49 (1)]. PMID:24046568

  4. Low-energy x-ray response of photographic films. II. Experimental characterization

    SciTech Connect

    Henke, B.L.; Fujiwara, F.G.; Tester, M.A.; Dittmore, C.H.; Palmer, M.A.

    1984-12-01

    Optical density versus exposure data have been obtained at nine photon energies in the 100--2000-eV x-ray region for five spectroscopic films (Kodak films 101-07, SB-392, RAR 2492, RAR 2495, and RAR 2497). These data were determined operationally by a direct comparison of the peak absolute intensities of spectral lines, which were measured with a calibrated proportional counter, with the microdensitometer tracings of the corresponding photographically recorded spectral lines. Film-resolution limits were deduced from an analysis of contact microradiograms of linear zone plates constructed of gold bars. The relationship between the specular densities as measured here and the diffuse densities have been experimentally determined for the five films. Finally, experimental measurements of the optical density versus the angle of incidence of exposing radiation of constant intensity were obtained. These data, relating density to the x-ray intensity, its photon energy, and its angle of incidence, are shown to be fitted satisfactorily in the 100--10 000-eV region by the semiempirical mathematical model relations that were derived in Part I of this research (J. Opt. Soc. Am. B 1, 818--827 (1984)).

  5. 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.

  6. Towards an acoustic model-based poroelastic imaging method: II. experimental investigation.

    PubMed

    Berry, Gearóid P; Bamber, Jeffrey C; Miller, Naomi R; Barbone, Paul E; Bush, Nigel L; Armstrong, Cecil G

    2006-12-01

    Soft biological tissue contains mobile fluid. The volume fraction of this fluid and the ease with which it may be displaced through the tissue could be of diagnostic significance and may also have consequences for the validity with which strain images can be interpreted according to the traditional idealizations of elastography. In a previous paper, under the assumption of frictionless boundary conditions, the spatio-temporal behavior of the strain field inside a compressed cylindrical poroelastic sample was predicted (Berry et al. 2006). In this current paper, experimental evidence is provided to confirm these predictions. Finite element modeling was first used to extend the previous predictions to allow for the existence of contact friction between the sample and the compressor plates. Elastographic techniques were then applied to image the time-evolution of the strain inside cylindrical samples of tofu (a suitable poroelastic material) during sustained unconfined compression. The observed experimental strain behavior was found to be consistent with the theoretical predictions. In particular, every sample studied confirmed that reduced values of radial strain advance with time from the curved cylindrical surface inwards towards the axis of symmetry. Furthermore, by fitting the predictions of an analytical model to a time sequence of strain images, parametric images of two quantities, each related to one or more of three poroelastic material constants were produced. The two parametric images depicted the Poisson's ratio (nu(s)) of the solid matrix and the product of the aggregate modulus (H(A)) of the solid matrix with the permeability (k) of the solid matrix to the pore fluid. The means of the pixel values in these images, nu(s) = 0.088 (standard deviation 0.023) and H(A)k = 1.449 (standard deviation 0.269) x 10(-7) m(2) s(-1), were in agreement with values derived from previously published data for tofu (Righetti et al. 2005). The results provide the first

  7. Metallothionein I+II expression as an early sign of chronic relapsing experimental autoimmune encephalomyelitis in rats.

    PubMed

    Jakovac, Hrvoje; Tota, Marin; Grebic, Damir; Grubic-Kezele, Tanja; Barac-Latas, Vesna; Mrakovcic-Sutic, Ines; Milin, Cedomila; Radosevic-Stasic, Biserka

    2013-02-01

    Metallothioneins (MTs) are small, cysteine-rich proteins which have been implicated in various forms of stress providing cytoprotective action against oxidative injury, DNA damage and apoptosis. Owing to their high affinity for physiological metals, such as zinc and copper MTs are also critical components of regulatory proteins involved in cell growth and multiplication, as well as in the maintenance of immune homeostasis. To elucidate the role of MTs in the pathomechanisms of autoimmune CNS disorders we estimated the expression of MT I+II proteins and the content of free Zn ions in the brain, spinal cord and in the liver early in the course of chronic relapsing experimental autoimmune encephalomyelitis (CR-EAE) pathogenesis, i.e. before the onset of any clinical symptoms. Disease was induced in the genetically susceptible Dark Agouti (DA) rats by subcutaneous injection of bovine brain homogenate in CFA. Control animals were treated with CFA alone. The data, obtained by immuno-histochemistry and in situ fluorescent labeling of free zinc ions, have shown that in the presymptomatic phase of CR-EAE (on the seventh postimmunization day) MTs I+II were markedly upregulated in the cells that form blood-brain and blood-cerebrospinal fluid barriers, as well as in the cerebellar parenchyma and hippocampal dentate gyri. Furthermore, we found that the liver also becomes a site of extensive MTs I+II synthesis shortly after immunization. Simultaneously, tissue content of free zinc ions increased at the sites of MTs induction, reflecting their antioxidative activity. The data, described in this paper point to regulatory and neuroprotective role of MTs in the pathogenesis of CR-EAE. PMID:23895520

  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. PMID:26995535

  9. Experimental investigation of aerodynamic devices for wind turbine rotational speed control: Phase II

    SciTech Connect

    Miller, S L

    1996-02-01

    An experimental investigation was undertaken to further evaluate and enhance the performance of an aerodynamic device for wind turbine overspeed protection and power modulation applications. The trailing-edge device, known as the Spoiler-Flap, was examined in detail during wind tunnel tests. The impact of hp length, vent angle, pivot point and chord variations on aerodynamic and hinge moment characteristics were evaluated and a best overall configuration was identified. Based on this effort, a 40% chord device with a 1% hp length and 40 degree vent angle offers improved performance potential for wind turbine applications. This specific configuration appears to offer good suction coefficient performance for both turbine power modulation and overspeed (i.e., aerodynamic braking) applications. Device hinge moment loads improved (compared to other devices investigated) in magnitude and the impact of surface roughness was found to be minimal.

  10. Multi-axial strain transfer from laminated CFRP composites to embedded Bragg sensor: II. Experimental validation

    NASA Astrophysics Data System (ADS)

    Voet, E.; Luyckx, G.; De Waele, W.; Degrieck, J.

    2010-10-01

    Embedded optical fibre sensors are considered in numerous applications for structural health monitoring purposes. Since the optical fibre and the host material in which it is embedded have different material properties, the strain in both materials will not be equal when external load is applied. Therefore, the strain transfer from the host material to the embedded sensor (optical fibre) was studied in more detail in the first part of the paper. This second part presents an experimental evaluation of the response of uni-axial fibre Bragg grating sensors embedded in small cross-ply composite laminates subjected to out-of-plane transverse loading. This loading case induces high birefringence effects in the core of the optical fibre. Using the numerically determined strain transfer coefficients (Luyckx et al 2010 Smart. Mater. Struct. 19 105017) together with multi-axial strain formulations, the authors were able to measure with reasonable accuracy the total strain field inside a carbon fibre reinforced plastic specimen.

  11. Maximum-likelihood methods in cryo-EM. Part II: application to experimental data

    PubMed Central

    Scheres, Sjors H.W.

    2010-01-01

    With the advent of computationally feasible approaches to maximum likelihood image processing for cryo-electron microscopy, these methods have proven particularly useful in the classification of structurally heterogeneous single-particle data. A growing number of experimental studies have applied these algorithms to study macromolecular complexes with a wide range of structural variability, including non-stoichiometric complex formation, large conformational changes and combinations of both. This chapter aims to share the practical experience that has been gained from the application of these novel approaches. Current insights on how to prepare the data and how to perform two- or three-dimensional classifications are discussed together with aspects related to high-performance computing. Thereby, this chapter will hopefully be of practical use for those microscopists wanting to apply maximum likelihood methods in their own investigations. PMID:20888966

  12. Shock-implanted noble gases. II - Additional experimental studies and recognition in naturally shocked terrestrial materials

    NASA Astrophysics Data System (ADS)

    Bogard, D.; Horz, F.; Johnson, P.

    1989-06-01

    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.

  13. Sedimentation equilibria of ferrofluids: II. Experimental osmotic equations of state of magnetite colloids.

    PubMed

    Luigjes, Bob; Thies-Weesie, Dominique M E; Erné, Ben H; Philipse, Albert P

    2012-06-20

    The first experimental osmotic equation of state is reported for well-defined magnetic colloids that interact via a dipolar hard-sphere potential. The osmotic pressures are determined from the sedimentation equilibrium concentration profiles in ultrathin capillaries using a low-velocity analytical centrifuge, which is the subject of the accompanying paper I. The pressures of the magnetic colloids, measured accurately to values as low as a few pascals, obey Van 't Hoff's law at low concentrations, whereas at increasing colloid densities non-ideality appears in the form of a negative second virial coefficient. This virial coefficient corresponds to a dipolar coupling constant that agrees with the coupling constant obtained via independent magnetization measurements. The coupling constant manifests an attractive potential of mean force that is significant but yet not quite strong enough to induce dipolar chain formation. Our results disprove van der Waals-like phase behavior of dipolar particles for reasons that are explained. PMID:22617544

  14. Experimental Analysis of hFACT Action during Pol II Transcription in vitro

    PubMed Central

    Hsieh, Fu-Kai; Kulaeva, Olga I.; Studitsky, Vasily M.

    2016-01-01

    Summary FACT (facilitates chromatin transcription) is a histone chaperone that facilitates transcription through chromatin and promotes histone recovery during transcription. Here, we describe a highly purified experimental system that recapitulates many important properties of transcribed chromatin and the key aspects of hFACT action during this process in vitro. We present the protocols describing how to prepare different forms of nucleosomes, including intact nucleosome, covalently conjugated nucleosome, nucleosome missing one of the two H2A/2B dimers (hexasome) and tetrasome (a nucleosome missing both H2A/2B dimers). These complexes allow analysis of various aspects of FACT’s function. These approaches and other methods described below can also be applied to the study of other chromatin remodelers and chromatin-targeted factors. PMID:25665573

  15. The role of aerobic activity on refuse temperature rise: II. Experimental and numerical modelling.

    PubMed

    Lanini, S; Houi, D; Aguilar, O; Lefebvre, X

    2001-02-01

    The biodegradation of a model waste is studied in a 300-litre pilot. The aim is to better understand the role of biochemical processes on the temperature rise, in relation to landfill management protocols. The variations of temperature and gas composition distributions in the waste are accurately measured and analysed. The observations confirm that biological consumption of the oxygen diffusing through the waste is the main source of heat. A theoretical modelling of coupled heat and oxygen transfers in fresh refuse is then proposed. Numerical results are in good agreement with experimental data, but it appears that biochemical kinetics should account for the carbon availability limitation. Finally, a prediction of the temperature field in a landfill is presented. PMID:11525476

  16. Experimental ulcerative herpetic keratitis. II. Influence of topical corticosteroid in immunised rabbits.

    PubMed Central

    Carter, C A; Easty, D L; Walker, S R

    1981-01-01

    Since the great majority of patients possess immune response to herpes simplex virus (HSV), the influence of a topical anti-inflammatory corticosteroid (0.1% clobetasone butyrate) on ulcerative herpetic keratitis was studied in rabbits with a previous HSV skin infection (immunised) and compared with that in normal rabbits. Corticosteroid treatment had a much greater ulceration-exacerbating effect in immunised than in normal animals. On day 7 the mean area of ulceration in immunised rabbits were 3 times greater in treated eyes. 0.01% clobetasone butyrate treatment had less effect on immunised rabbits; 0.001% had no effect. It is concluded that the immunised rabbit provides a useful experimental model for studying the relationship between concentration of topical anti-inflammatory agents and enhancement of herpetic ulceration. PMID:7260009

  17. 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

  18. Synthesis, spectral characterisation of 2-(5-methyl-1H-benzimidazol-2-yl)-4-bromo/nitro-phenols and their complexes with zinc(II) ion, and solvent effect on complexation.

    PubMed

    Tavman, Aydin

    2006-02-01

    2-(5-Methyl-1H-benzimidazol-2-yl)-4-bromo/nitro-phenols (HLBr and HLNO2) and their Zn(II) complexes with ZnX2 (X = Cl, I, NO3) were synthesized and characterized by elemental analysis, molar conductivity, IR, 1H and 13C NMR spectra. The OH proton appears near the NH protons in the 1H NMR spectra of the ligands because of the strong intramolecular hydrogen bonding between the OH hydrogen and the C=N nitrogen atoms. The complexation is investigated in ethanol and isopropanol and it is observed that isopropanol is a better solvent than ethanol for the complex forming. HLBr gives harder complexation reaction with Zn(II) according to HLNO2 because of the stronger intramolecular hydrogen bonding in HLBr, and the both ligands react easier with Zn(NO3)2 than ZnCl2 and ZnI2. The Zn(II) complexes of HLBr have 1:1 M:L ratio and ionic character, however, HLNO2 give a non-ionic complex that has 1:2 M:L ratio. In the complexes the phenolic hydrogen is eliminated and a chelate structure is formed. PMID:15978864

  19. Crystal structure of [N,N'-bis-(4-methyl-phen-yl)-1,2-di-phenyl-ethane-1,2-di-imine-κ(2) N,N']di-chlorido-palladium(II) methanol monosolvate.

    PubMed

    Peñaloza, Alfredo; Fronczek, Frank R; Isovitsch, Ralph

    2015-09-01

    The title compound, [PdCl2(C28H24N2)]·CH3OH, was pre-pared from the reaction of PdCl2(DMSO)2 (DMSO is di-methyl sulfoxide) and N,N'-bis-(4-methyl-phen-yl)-1,2-di-phenyl-ethane-1,2-di-imine in methanol. The chelating di-imine core of the title compound deviates slightly from planarity, with an N-C-C-N torsion angle of 5.3 (3)°. Delocalization in the di-imine core is indicated by N-C and C-C bonds that are, respectively, longer and shorter than those found in related nonchelating di-imines. The distorted square-planar coordination environment around the Pd(II) atom is manifested as bond angles that are smaller and larger than 90°, and palladacycle torsion angles of -173.22 (16) and 167.06 (16)°. These deviations are attributed to the small bite angle of 79.13 (8)° of the di-imine chelate. The crystal packing exhibits weak inter-molecular hydrogen-bonding inter-actions involving aromatic H atoms, Cl atoms and inter-calated methanol solvent mol-ecules, defining layers parallel to (010). PMID:26396867

  20. Experimental study of the autoignition of C{sub 8}H{sub 16}O{sub 2} ethyl and methyl esters in a motored engine

    SciTech Connect

    Zhang, Yu.; Boehman, Andre L.

    2010-03-15

    Autoignition of two biodiesel surrogates, methyl heptanoate and ethyl hexanoate, was studied in a motored CFR engine at an equivalence ratio of 0.25 and an intake temperature of 155 C. The engine compression ratio was gradually increased from the lowest point (4.43) to the point where significant high temperature heat release (HTHR) occurred. Within the test range of this work, both of the two esters exhibited evident cool flame behavior. At the same compression ratio, methyl heptanoate was observed to have both an earlier onset and a higher magnitude of low temperature heat release (LTHR) than ethyl hexanoate, indicating that methyl heptanoate is more reactive in the low temperature region than ethyl hexanoate. GC-MS analyses of the reaction intermediates from the oxidation of the two esters showed that the alkyl chain of fatty acid esters experiences the typical paraffin-like low temperature oxidation sequence. Based on the observations from GC-MS analyses, major low temperature oxidation pathways of ethyl hexanoate are proposed in this work. Also, it is observed that the abstraction of H-atoms on the {alpha}-carbon of the ester carbonyl group plays an important role in the oxidation of fatty acid esters. In addition, the identification of hexanoic acid among the reaction intermediates from low temperature oxidation of ethyl hexanaoate together with the observation of more fuel carbon being converted to C{sub 2}H{sub 4} during ethyl hexanoate oxidation than during methyl heptanoate oxidation provide evidence for the existence of the six-centered unimolecular elimination reaction during low temperature oxidation of ethyl esters. (author)

  1. 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.

  2. 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.

  3. The sensitizing capacity of naturally occurring quinones. Experimental studies in guinea pigs. II. Benzoquinones.

    PubMed

    Schulz, K H; Garbe, I; Hausen, B M; Simatupang, M H

    1979-05-01

    Experimental studies on the sensitizing capacity of naturally occurring benzoquinones, isolated from plants and woods have been carried out in guinea pigs of the Pirbright white strain. Seven compounds were available: primin, three dalbergiones, mansonia quinone (mansonone A), 2,6-dimethoxybenzoquinone and rapanone. With five of these substances (primin, mansonone A, three dalbergiones) guinea pigs could be sensitized. Primin, the allergen of Primula obconica Hance (primrose) proved to be the most effective one of all quinones tested in this and the preceding studies. As a similar but weaker sensitizer R-3, 4-dimethoxydalbergione from Machaerium scleroxylon Tul. (Pao ferro, Caviuna vermelha) could be identified. The results obtained with mansonone A, a sesquiterpenoid quinone from Mansonia altissima A. Chev. demonstrate that even naturally occurring orthoquinones are capable of inducing contact allergy. Allergic cross reactions could be obtained between all chemically related mansonones A-F. The results are in good accordance with the view that the sensitizing capacity of naturally occurring quinones depends on the fundamental quinoid structure and the length, position and configuration of the aliphatic side-chain. PMID:464645

  4. Bis(thiosemicarbazonato) chelates of Co(II), Ni(II), Cu(II), Pd(II) and Pt(II)

    NASA Astrophysics Data System (ADS)

    Chandra, Sulekh; Singh, R.

    1985-01-01

    Bis chelates of Co(II), Ni(II), Cu(II), Pd(II) and Pt(II) with the enolic form of diethyl ketone and methyl n-propyl thiosemicarbazones were synthesized and characterized by elemental analyses, magnetic moments, i.r. and electronic and electron spin resonance spectral studies. All the complexes were found to have the composition ML 2 [where M = Co(II), Ni(II), Cu(II), Pd(ii) and Pt(II) and L = thiosemicarbazones of diethyl ketone and methyl n-propyl ketone]. Co(II) and Cu(II) complexes are paramagnetic and may have polymeric six-coordinate octahedral and square planar geometries, respectively. The Ni(II), Pd(II) and Pt(II) complexes are diamagnetic and may have square planar geometries. Pyridine adducts (ML 2·2Py) of Ni(II) and Cu(II) complexes were also prepared and characterized.

  5. Synthesis of comb type and semi-interpenetrating networks of acryloyl- L-proline methyl ester and poly (acrylic acid) for Cu (II) immobilization

    NASA Astrophysics Data System (ADS)

    González, Giovanni; Burillo, Guillermina

    2010-08-01

    Graft copolymer hydrogels and semi-interpenetrating networks (s-IPN) of acryloyl- L-proline methyl ester (A-ProOMe) and poly (acrylic acid) (PAAc) were synthesized in methanol solutions, by ionizing radiation (γ rays from a Co 60 source at room temperature). These systems are thermo and pH-sensitive and the pH sensitivity increases from acidic to basic solutions. The Lower Critical Solution Temperature (LCST), due to presence of poly (acryloyl- L-proline methyl ester) (PA-ProOMe) has been found between 18 and 20 °C and an unexpected Upper Critical Solution Temperature (UCST) due to poly acrylic acid (PAAc) has been found between 21 and 22 °C. Preliminary studies on the immobilization of Cu 2+ for both hydrogels were done at several pH values at room temperature. Other techniques employed to characterize the comb type hydrogels and sIPN included scanning electronic microscopy (SEM) and infrared (FTIR-ATR).

  6. μ-(2,6-Bis{[3-(di­methyl­amino)­prop­yl]imino­meth­yl}-4-methyl­phenolato)-μ-hydroxido-bis­[(thio­cyanato-κN)copper(II)

    PubMed Central

    Meera, M. G.; Selvaraj, P. Kamatchi; Viswanathan, B.; Ramkumar, V.

    2013-01-01

    In the title compound, [Cu2(C19H31N4O)(OH)(NCS)2], the mol­ecular structure of the dinuclear complex reveals two penta­coordinated CuII ions, which are bridged by the phenolate O atom of the ligand and by an exogenous hydroxide ion. The bridging atoms occupy equatorial positions in the coordination sphere of the metal atoms and complete the equatorial coordination planes with two ligand N atoms, the apical positions being occupied by thio­cyanate N atoms. The crystal structure also features π–π stacking inter­actions involving the benzene rings with a centroid–centroid distance of 3.764 (4)Å. The crystal studied was a non-merohedral twin, with a refined BASF value of 0.203 (2) PMID:24098174

  7. 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

  8. 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.

  9. Directed assembly and characterization of 1D polymers based on [M(II)(BMA)]2+ node (M = Cu, Mn, Ni and Zn; BMA = N,N-bis (benzimidazol-2-yl-methyl)amine) with linear bridging dicyanamide and terephthalate ligands.

    PubMed

    Xu, Jing-Yuan; Xie, Cheng-Zhi; Xue, Fei; Hao, Lan-Fang; Ma, Zhong-Ying; Liao, Dai-Zheng; Yan, Shi-Ping

    2010-08-14

    The directed assembly of N,N-bis(benzimidazol-2-yl-methyl)amine (BMA) with Cu(II), Mn(II), Ni(II) and Zn(II) salts based on dicyanamide (mu(1,5)-dca) and terephthalate (mu-ta) linear bridging ligands, respectively, leads to four novel compounds: [Cu(BMA)(mu(1,5)-dca)(ClO(4))](n) (1), {[Mn(BMA)(mu(1,5)-dca)(CH(3)OH)] x ClO(4) x C(10)H(9)N(3)O x CH(3)OH}(n) (2), {[Ni(2)(BMA)(2)(mu-ta)(mu(1,5)-dca)] x ClO(4) x CH(3)OH x H(2)O}(n) (3), and {[Zn(2)(BMA)(2)(mu-ta)(mu(1,5)-dca)] x ClO(4) x CH(3)OH}(n) (4), which were characterized by single-crystal X-ray diffraction, elemental analysis, IR, fluorescence spectroscopy, and magnetic measurement. X-Ray analysis revealed that 1 and 2 are two infinite 1D coordination polymers, in which dca units serving as an end-to-end out-of-plane bridge bring about linear chains for 1 and zigzag chains for 2. Complexes 3 and 4 are similar, in which the metal atoms are bridged alternately by terephthalate and mu(1,5)-dicyanamide ligands into 1D zigzag chains. In all these complexes, each BMA ligand adopts a tridentate chelating mode to coordinate with a transition metal forming a [M(BMA)](2+) node. Different rigidity bridging ligands together with the stereochemistry and supramolecular effects of benzimidazol planes may result in the dramatic structural changes from 1D to multidimensional networks for all 1-4. Fluorescent measurements established that, in solution, complex 3 displays weak blue luminescence which originates from the BMA but is significantly red-shifted and has a much lower emission intensity, compared to the free BMA ligand. Complex 4 shows stronger luminescence than 3 and still reduces luminescence efficiency compared to the free BMA ligand. The variable-temperature magnetic susceptibility measurements (2-300 K) of 1 and 3 show the dominant weak ferromagnetic interactions between the copper(II) centers with J = 3.02 cm(-1), zJ' = -2.70 cm(-1) for 1, and the nickel(II) centers with J = 1.94 cm(-1), J'; = -0.38 cm(-1) for 3

  10. Methyl gallate.

    PubMed

    Bebout, Deborah; Pagola, Silvina

    2009-01-01

    THE CRYSTAL STRUCTURE OF THE TITLE COMPOUND (SYSTEMATIC NAME: methyl 3,4,5-trihydroxy-benzoate), C(8)H(8)O(5), is composed of essentially planar mol-ecules [maximum departures from the mean carbon and oxygen skeleton plane of 0.0348 (10) Å]. The H atoms of the three hydroxyl groups, which function as hydrogen-bond donors and acceptors simultaneously, are oriented in the same direction around the aromatic ring. In addition to two intra-molecular hydrogen bonds, each mol-ecule is hydrogen bonded to six others, creating a three-dimensional hydrogen-bonded network. PMID:21581923

  11. Methyl gallate

    PubMed Central

    Bebout, Deborah; Pagola, Silvina

    2009-01-01

    The crystal structure of the title compound (systematic name: methyl 3,4,5-trihydroxy­benzoate), C8H8O5, is composed of essentially planar mol­ecules [maximum departures from the mean carbon and oxygen skeleton plane of 0.0348 (10) Å]. The H atoms of the three hydroxyl groups, which function as hydrogen-bond donors and acceptors simultaneously, are oriented in the same direction around the aromatic ring. In addition to two intra­molecular hydrogen bonds, each mol­ecule is hydrogen bonded to six others, creating a three-dimensional hydrogen-bonded network. PMID:21581923

  12. The origin and fate of 4-methyl steroid hydrocarbons. I. Diagenesis of 4-methyl sterenes

    NASA Astrophysics Data System (ADS)

    Wolff, George A.; Lamb, Neil A.; Maxwell, James R.

    1986-03-01

    Treatment of 4-methylcholest-4-ene under mild acid conditions at low temperatures gives chemical evidence for certain features seen in the distributions of sedimentary 4-methyl steroid hydrocarbons, and further indicates that many low temperature diagenetic reactions of steroids are explicable in terms of acid catalysed rearrangements. Specifically, the results provide: (i) Indirect evidence that the 4-ene skeleton is a key intermediate in the dehydration of 4-methyl stanols in sediments. (ii) An explanation for the distribution of 4-methyl sterenes and A-nor sterenes in the lacustrine Messel shale (Eocene). (iii) An explanation for the presence of 4β-methyl steranes in relatively immature sedimentary rocks, despite the precursor stanols having the 4α-methyl configuration. With increasing maturity in the Paris Basin shales (Lower Toarcian), the less stable 4β-methyl steranes decrease gradually in abundance relative to their 4α-methyl counterparts, at a rate fairly similar to the change in pristane stereochemistry.

  13. Synthesis, spectroscopic properties, crystal structure and density functional studies of Cu(II) complex with 2-((dehydroabietylamine)methyl)-6-methoxyphenol

    NASA Astrophysics Data System (ADS)

    Liu, Bao-Yu; Liu, Zheng; Han, Guo-Cheng; Li, Yan-Hong

    2010-06-01

    The metal complex of CuL 2 (L = 2-((dehydroabietylamine)methyl)-6-methoxyphenol) has been synthesized and characterized by spectral method (IR), elemental analysis, thermal analysis (TG, DTG) and single crystal X-ray diffraction techniques. Molecular geometry from X-ray experiment of the title compound in the ground-state has been compared using the density functional method (B3LYP) with LANL2DZ basis set. UV-vis spectra has been measured and DFT calculations at B3LYP/LANL2DZ level of theory proved that the electronic spectra of CuL 2 was attributed to intra-complex electronic transitions as well as d- d electronic transitions. Besides, Mulliken charge analysis, natural bond orbitals (NBO), frontier molecular orbitals (FMO) were performed at B3LYP/LANL2DZ level of theory.

  14. Palladium(II) Complexes Containing Mixed Nitrogen-Sulphur Donor Ligands: Interaction of [Pd(Methionine Methyl Ester)(H2O)2]2+ with Biorelevant Ligands

    PubMed Central

    Shoukry, Mohamed M.; Ezzat, Sameya M. T.

    2014-01-01

    Pd(MME)Cl2 complex (MME = methionine methyl ester) was synthesised and characterized by physicochemical measurements. The reaction of [Pd(MME)(H2O)2]2+ with amino acids, peptides, or dicarboxylic acids was investigated at 25°C and 0.1 M ionic strength. Amino acids and dicarboxylic acids form 1 : 1 complexes. Peptides form both 1 : 1 complexes and the corresponding deprotonated amide species. The stability of the complexes formed was determined and the binding centres of the ligands were assigned. Effect of solvent on the stability constant of Pd(MME)-CBDCA complex, taken as a representative example, shows that the complex is more favoured in a medium of low dielectric constant. The concentration distribution diagrams of the complexes were evaluated. PMID:25214826

  15. 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

    2013-06-01

    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

  16. Dimeric and polymeric mercury(II) complexes of 1-methyl-1,2,3,4-tetrazole-5-thiol: Synthesis, crystal structure, spectroscopic characterization, and thermal analyses

    NASA Astrophysics Data System (ADS)

    Taheriha, Mohammad; Ghadermazi, Mohammad; Amani, Vahid

    2016-03-01

    Two-dimensional coordination polymer of [Hg(μ3-mmtz)2]n (1) and centrosymmetric dinuclear complexes of {[H2en][Hg2(mmtz)4(μ-Br)2]} (2) and {[H2en][Hg2(mmtz)4(μ-I)2]} (3) (where Hmmtz is 1-methyl-1,2,3,4-tetrazole-5-thiol and en is ethylene diamine) were synthesized from the reaction of Hmmtz and en with HgCl2, HgBr2 and HgI2, respectively, in CH3OH. Complex 1 was also synthesized from the reaction of Hmmtz and en with HgX2 (X = OAc and SCN) in CH3OH. These three complexes were thoroughly characterized by elemental analysis (CHN), thermal gravimetric analysis (TGA), differential thermal analyses (DTA), infrared, UV-vis, 1H NMR, and luminescence spectroscopy, and their structures were determined by single-crystal X-ray diffraction.

  17. Bis[(di­methyl­phosphor­yl)methan­amin­ium] tetra­chlorido­palladate(II)

    PubMed Central

    Reiss, Guido J.

    2013-01-01

    In the crystal structure of the title compound, (C3H11NOP)2[PdCl4], (di­methyl­phosphor­yl)methanaminium (dpmaH+) cations are connected head-to-tail by strong N—H⋯O hydrogen bonds, forming inversion-related cyclic dimers. The square-planar [PdCl4]2− counter-dianion is located about a center of inversion. The dications and the [PdCl4]2− dianions are connected by medium–strong N—H⋯Cl hydrogen bonds, forming zigzag chains parallel to [001]. Somewhat weaker N—H⋯Cl hydrogen bonds connect the chains into a three-dimensional network. PMID:24454042

  18. Detailed Chemical Kinetic Reaction Mechanism for Biodiesel Components Methyl Stearate and Methyl Oleate

    SciTech Connect

    Naik, C; Westbrook, C K; Herbinet, O; Pitz, W J; Mehl, M

    2010-01-22

    New chemical kinetic reaction mechanisms are developed for two of the five major components of biodiesel fuel, methyl stearate and methyl oleate. The mechanisms are produced using existing reaction classes and rules for reaction rates, with additional reaction classes to describe other reactions unique to methyl ester species. Mechanism capabilities were examined by computing fuel/air autoignition delay times and comparing the results with more conventional hydrocarbon fuels for which experimental results are available. Additional comparisons were carried out with measured results taken from jet-stirred reactor experiments for rapeseed methyl ester fuels. In both sets of computational tests, methyl oleate was found to be slightly less reactive than methyl stearate, and an explanation of this observation is made showing that the double bond in methyl oleate inhibits certain low temperature chain branching reaction pathways important in methyl stearate. The resulting detailed chemical kinetic reaction mechanism includes more approximately 3500 chemical species and more than 17,000 chemical reactions.

  19. 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

    2015-12-01

    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. PMID:26247229

  20. [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

  1. Synthesis, molecular structure, spectral analysis and nonlinear optical studies on 4-(4-bromophenyl)-1-tert-butyl-3-methyl-1H-pyrazol-5-amine: A combined experimental and DFT approach

    NASA Astrophysics Data System (ADS)

    Tamer, Ömer; Arslan, Barış Seçkin; Avcı, Davut; Nebioğlu, Mehmet; Atalay, Yusuf; Çoşut, Bünyemin

    2016-02-01

    4-(4-bromophenyl)-1-tert-butyl-3-methyl-1H-pyrazol-5-amine (BPTBMPA) crystal was synthesized for the first time and its structural characterization was performed by X-ray diffraction method. The spectroscopic characterization was also performed by the applying of FT-IR, UV-Vis, 1H and 13C NMR spectroscopies. In order to support experimental results, density functional theory calculations have been performed. All of the obtained theoretical results are in a perfect agreement with the experimental ones. The negative HOMO and LUMO energies demonstrated that the molecular structure of BPTBMPA is stable. The small energy gap between the HOMO and LUMO is an indicator of intramolecular charge transfer which is responsible for nonlinear optical properties. Natural bond orbital analysis also indicates the presence of molecular charge transfer within BPTBMPA. Obtained chemical hardness parameter demonstrates that BPTBMPA has considerable electron donor groups. Finally, it has been showed that BPTBMPA exhibits considerable nonlinear optical properties.

  2. Heat Transfer Measurements of the First Experimental Layer of the Fire II Reentry Vehicle in Expansion Tubes

    NASA Astrophysics Data System (ADS)

    Capra, B. R.; Morgan, R. G.; Leyland, P.

    2005-02-01

    The present study focused on simulating a trajectory point towards the end of the first experimental heatshield of the FIRE II vehicle, at a total flight time of 1639.53s. Scale replicas were sized according to binary scaling and instrumented with thermocouples for testing in the X1 expansion tube, located at The University of Queensland. Correlation of flight to experimental data was achieved through the separation, and independent treatment of the heat modes. Preliminary investigation indicates that the absolute value of radiant surface flux is conserved between two binary scaled models, whereas convective heat transfer increases with the length scale. This difference in the scaling techniques result in the overall contribution of radiative heat transfer diminishing to less than 1% in expansion tubes from a flight value of approximately 9-17%. From empirical correlation's it has been shown that the St √ Re number decreases, under special circumstances, in expansion tubes by the percentage radiation present on the flight vehicle. Results obtained in this study give a strong indication that the relative radiative heat transfer contribution in the expansion tube tests is less than that in flight, supporting the analysis that the absolute value remains constant with binary scaling. Key words: Heat Transfer, Fire II Flight Vehicle, Expansion Tubes, Binary Scaling. NOMENCLATURE dA elemental surface area, m2 H0 stagnation enthalpy, MJ/kg L arbitrary length, m ls scale factor equal to Lf /Le M Mach Number ˙m mass flow rate, kg/s p pressure, kPa ˙q heat transfer rate, W/m2 ¯q averaged heat transfer rate W/m2 RN nose radius m Re Reynolds number, equal to ρURN µ s/RD radial distance from symmetry axis St Stanton number, equal to ˙q ρUH0 St √ Re = ˙qR 1/2 N (ρU)1/2 µ1/2H0 over radius of forebody (D/2) T temperature, K U velocity, m/s Ue equivalent velocity m/s, equal to √ 2H0 U1 primary shock speed m/s U2 secondary shock speed m/s ρ density, kg/m3 ρL binary

  3. Role of Radical Species in Salicylaldiminato Ni(II) Mediated Polymer Chain Growth: A Case Study for the Migratory Insertion Polymerization of Ethylene in the Presence of Methyl Methacrylate.

    PubMed

    Ölscher, Franz; Göttker-Schnetmann, Inigo; Monteil, Vincent; Mecking, Stefan

    2015-11-25

    To date, an inconclusive and partially contradictive picture exists on the behavior of neutral Ni(II) insertion polymerization catalysts toward methyl methacrylate (MMA). We shed light on this issue by a combination of comprehensive mechanistic NMR and EPR studies, isolation of a key Ni(I) intermediate, and pressure reactor studies with ethylene and MMA, followed by detailed polymer analysis. An interlocking mechanistic picture of an insertion and a free radical polymerization is revealed. Both polymerizations run simultaneously (25 bar ethylene, neat MMA, 70 °C); however, the chain growth cycles are independent of each other, and therefore exclusively a physical mixture of homo-PE and homo-PMMA is obtained. A Ni-C bond cleavage was excluded as a free radical source. Rather a homolytic P-C bond cleavage in the labile aryl phosphine ligand and the reaction of low-valent Ni(0/I) species with specific iodo substituted N^O (Ar-I) ligands were shown to initiate radical MMA polymerizations. Several reductive elimination decomposition pathways of catalyst precursor or active intermediates were shown to form low-valent Ni species. One of those pathways is a bimolecular reductive coupling via intermediate (N^O)Ni(I) formation. These intermediate Ni(I) species can be prevented from ultimate decomposition by capturing with organic radical sources, forming insertion polymerization active [(N^O)Ni(II)-R] species and prolonging the ethylene polymerization activity. PMID:26571229

  4. Experimental study of the removal of copper ions using hydrogels of xanthan, 2-acrylamido-2-methyl-1-propane sulfonic acid, montmorillonite: Kinetic and equilibrium study.

    PubMed

    Aflaki Jalali, Marzieh; Dadvand Koohi, Ahmad; Sheykhan, Mehdi

    2016-05-20

    In this paper, removal of copper ions from aqueous solution using novel xanthan gum (XG) hydrogel, xanthan gum-graft-2-acrylamido-2-methyl-1-propane sulfonic acid (XG-g-P(AMPS)) hydrogel and xanthan gum-graft-2-acrylamido-2-methyl-1-propane sulfonic acid/montmorillonite (XG-g-P(AMPS)/MMT) hydrogel composite were studied. The structure and morphologies of the xanthan-based hydrogels were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). Adsorbents comprised a porous crosslink structure with side chains that carried carboxyl, hydroxyl and sulfonate. Maximum adsorption was observed in the pH=5.2, initial concentrations of Cu(2+)=321.8 mg/L, Temperature=45 °C, contact time=5 h with 0.2 g/50 mL of the hydrogels. Adsorption process was found to follow Langmuir isotherm model with maximum adsorption capacity of 24.57, 39.06 and 29.49 mg/g for the XG, XG-g-P(AMPS) and XG-g-P(AMPS)/MMT, respectively. Adsorption kinetics data fitted well with pseudo second order model. The negative ΔG° values and the positive ΔS° confirmed that the adsorption was a spontaneous process. The positive ΔH° values suggested that the adsorption was endothermic in nature. PMID:26917382

  5. Distribution of 1-methyl-4-phneyl-1,2,3,6-tetrahydropyridine in experimental animals studied by positron emission tomography and whole body autoradiography

    SciTech Connect

    Hartvig, P.; Lindquist, N.G.; Aquilonius, S.M.; d'Argy, R.; Bergstroem, K.; Bondesson, U.; Eckernaes, S.A.; Gullberg, P.; Larsson, B.S.; Lindberg, B.

    1986-01-06

    1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is a selective potent neurotoxin which has induced a syndrome similar to parkinsonism both in man and in monkeys. At autopsy degeneration of pigmented nerve cells in the pars compacta of the substantia nigra has been confirmed. The regional distribution of intravenously administered 1-(/sup 11/C-methyl)-4-phenyl-1,2,3,6-tetrahydropyridine (/sup 11/C-MPTP) in the brain of Rhesus monkeys was studied by positron emission tomography and the whole body distribution in mice was documented by autoradiography and by impulse counting of selected tissues. A rapid and high uptake of /sup 11/C-MPTP derived radioactivity was seen in areas corresponding to striatum and midbrain, including the substantia nigra area. Pretreatment of the monkey with spiperone, a selective dopamine receptor antagonist, did not alter uptake nor the kinetics of the /sup 11/C-MPTP derived radioactivity. Thus, /sup 11/C-MPTP does not have a high affinity for postsynaptic dopamine receptors. A remarkably high uptake of /sup 11/C-MPTP derived radioactivity was seen in the eye of the monkey. The selective uptake of radioactivity in the eye was also confirmed in pigmented but not in albino mice. The melanin affinity of MPTP may cause high intracellular concentrations of the compound or its metabolites in the melanin containing nerve cells in substantia nigra, which may explain the serious vulnerability of these neurons to MPTP. 30 references, 3 figures, 2 tables.

  6. (Cyanato-κN){1-[(E)-phen­yl(pyridin-2-yl-κN)methyl­idene]semicarbazidato-κ2 N 1,O}copper(II)

    PubMed Central

    Kunnath, Roji J.; Prathapachandra Kurup, M.R.; Ng, Seik Weng

    2012-01-01

    The CuII atom in the title compound, [Cu(C13H11N4O)(NCO)], is N,N′,O-chelated by the mono-deprotonated Schiff base ligand and it is also covalently bonded to the nitro­gen end of the cyanate ion. The CuII atom shows a square-planar coordination that is distorted towards square-pyramidal owing to an inter­molecular Cu⋯Ncyanate inter­action [2.623 (2) Å], which gives a centrosymmetric dimer. In the square-planar description, the CuII atom is displaced out of the square plane [r.m.s. deviation = 0.048 Å] by 0.084 (1) Å in the direction of the apical occupant. In the crystal, adjacent complex dimers are linked by an amine N—H⋯N hydrogen-bond pair, also giving a centrosymmetric cyclic association [graph set R 2 2(8)], generating a linear chain parallel to [110]. PMID:22969475

  7. The FERRUM project: Experimental lifetimes and transition probabilities from highly excited even 4d levels in Fe ii

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

    We report lifetime measurements of the 6 levels in the 3d6(5D)4d e6G term in Fe ii at an energy of 10.4 eV, and f-values for 14 transitions from the investigated levels. The lifetimes were measured using time-resolved laser-induced fluorescence on ions in a laser-produced plasma. The high excitation energy, and the fact that the levels have the same parity as the the low-lying states directly populated in the plasma, necessitated the use of a two-photon excitation scheme. The probability for this process is greatly enhanced by the presence of the 3d6(5D)4p z6F levels at roughly half the energy difference. The f-values are obtained by combining the experimental lifetimes with branching fractions derived using relative intensities from a hollow cathode discharge lamp recorded with a Fourier transform spectrometer. The data is important for benchmarking atomic calculations of astrophysically important quantities and useful for spectroscopy of hot stars.

  8. Two-Dimensional Electronic Spectroscopy of Light-Harvesting Complex II at Ambient Temperature: A Joint Experimental and Theoretical Study.

    PubMed

    Duan, Hong-Guang; Stevens, Amy L; Nalbach, Peter; Thorwart, Michael; Prokhorenko, Valentyn I; Miller, R J Dwayne

    2015-09-10

    We have performed broad-band two-dimensional (2D) electronic spectroscopy of light-harvesting complex II (LHCII) at ambient temperature. We found that electronic dephasing occurs within ∼60 fs and inhomogeneous broadening is approximately 120 cm(-1). A three-dimensional global fit analysis allows us to identify several time scales in the dynamics of the 2D spectra ranging from 100 fs to ∼10 ps and to uncover the energy-transfer pathways in LHCII. In particular, the energy transfer between the chlorophyll b and chlorophyll a pools occurs within ∼1.1 ps. Retrieved 2D decay-associated spectra also uncover the spectral positions of corresponding diagonal peaks in the 2D spectra. Residuals in the decay traces exhibit periodic modulations with different oscillation periods. However, only one of them can be associated with the excitonic cross-peaks in the 2D spectrum, while the remaining ones are presumably of vibrational origin. For the interpretation of the spectroscopic data, we have applied a refined exciton model for LHCII. It reproduces the linear absorption, circular dichroism, and 2D spectra at different waiting times. Several components of the energy transport are revealed from theoretical simulations that agree well with the experimental observations. PMID:26301382

  9. Aggregation effect on the luminescence properties of phenylbipyridine Pt(II) acetylide complexes. A theoretical prediction with experimental evidence.

    PubMed

    Amar, Anissa; Meghezzi, Hacène; Boixel, Julien; Le Bozec, Hubert; Guerchais, Véronique; Jacquemin, Denis; Boucekkine, Abdou

    2014-08-14

    We report a combined theoretical and experimental study of both the structural and optical properties of phosphorescent cyclometalated square-planar (phenylbipyridyl)platinum(II) acetylide complexes, namely (Pt(tBu2-ĈN̂N)(C≡C-Ph)] and (Pt(hex2-ĈN̂N)(C≡C-thienyl)] that exhibit, at high concentrations, an additional emission band at longer wavelength. The geometry optimizations of both the ground and the lowest triplet excited states of the considered monomers and different possible dimers have been performed in solution using several density functional theory (DFT) functionals corrected for dispersion effects. For the dimers, which are shown to exhibit a head-to-tail configuration, a significant shortening of the Pt···Pt distance, compared to that in the ground state, is observed in the first triplet state. Moreover, we show that trimeric species are highly improbable in solution. The UV-visible absorption spectra of the complexes are well rationalized using a vertical time-dependent DFT (TD-DFT) protocol relying on a global hybrid exchange-correlation functional. Finally, the new emission band at high concentration of the complexes can be assigned to a metal-metal to ligand charge transfer excited state ((3)MMLCT). PMID:25079349

  10. Solar Neutrinos. II. Experimental

    DOE R&D Accomplishments Database

    Davis, Raymond Jr.

    1964-01-01

    A method is described for observing solar neutrinos from the reaction Cl{sup 37}(nu,e{sup -})Ar{sup 37} in C{sub 2}Cl{sub 4}. Two 5 00-gal tanks of C{sub 2}Cl{sub 4} were placed in a limestone mine (1800 m.w.e.) and the resulting Ar{sup 37} activity induced by cosmic mesons( mu ) was measured to determine the necessary conditions for solar neutrino observations. (R.E.U.)

  11. Crystal structure of bis­(1-hexyl-N,N-di­methyl­pyridinium) bis­(maleo­nitrile­dithiol­ato)nickelate(II)

    PubMed Central

    Yu, Shan-Shan; Zhang, Hui

    2016-01-01

    The asymmetric unit of the title compound, (C13H23N2)2[Ni(C4N2S2)2], consists of a 1-hexyl-N,N-di­methyl­pyridinium cation and one half of a [Ni(mnt)2]2− dianion (mnt2− = maleo­nitrile­dithiol­ate) in which the Ni2+ cation lies on a crystallographic inversion centre. The square-planar coordination about Ni2+ comprises four S atoms from two bidentate chelate mnt2− ligands [Ni—S = 2.1791 (9) and 2.1810 (8) Å, and S—Ni—S bite angle = 91.93 (3)°]. The hydro­carbon chains of cations show trans-planar conformations and lie approximately parallel to the long mol­ecular axis of the [Ni(mnt)2]2− anions, giving stacks along the c axis. The anions and cations form layers lying parallel to the bc plane. Only weak C—H⋯Ni and C—H⋯π associations are present in the crystal packing. PMID:27536413

  12. Synthesis, characterization, crystal structure and theoretical approach of Cu(II) complex with 4-{(Z)-[(2-hydroxybenzoyl)hydrazono]methyl}benzoic acid

    NASA Astrophysics Data System (ADS)

    Chen, Shi-Liang; Liu, Zheng; Liu, Jie; Han, Guo-Cheng; Li, Yan-Hong

    2012-04-01

    The metal complex of [CuL2]·2DMF (L = 4-{(Z)-[(2-hydroxybenzoyl)hydrazono]methyl}benzoic acid, DMF = N,N-dimethylformamide) (1) had been synthesized and characterized by spectral method(IR), UV-Vis electronic absorption spectra, fluorescence spectra, elemental analysis, electrochemistry, thermal analysis (TG, DTG) and single crystal X-ray diffraction techniques. In the complex, the ligands act as univalent anion bidentate and coordination takes place in the enol tautomeric form with the enolic oxygen and azomethine nitrogen atoms. Molecular geometry from X-ray experiment of the title compound in the ground-state has been compared using the density functional method (B3LYP) and LANL2DZ basis set. DFT calculations at B3LYP/LANL2DZ level of theory prove that the electronic spectra of CuL2·2DMF is attributed to intra-complex electronic transitions as well as π-π* electronic transitions. Also, Mulliken charge analysis, natural bond orbitals (NBO), Wiberg bond index and frontier molecular orbitals (FMO) were performed at B3LYP/LANL2DZ level of theory. In addition, complex 1 exhibits strong photoluminescent emission at room temperature. The electrochemical studies reveal that redox of Cu2+/Cu+ in the complex are quasi-reversible processes. The result of TG analysis shows that the title complex was stable under 100.0 °C.

  13. Synthesis, crystal structure and spectral properties of 2-[(1-Methyl-2-benzimidazolyl)azo]-p-cresol: An experimental and theoretical study

    NASA Astrophysics Data System (ADS)

    Sarkar, Deblina; Pramanik, Ajoy Kumar; Mondal, Tapan Kumar

    2013-11-01

    2-[(1-Methyl-2-benzimidazolyl)azo]-p-cresol (HL), containing phenolic-OH function and benzimidazole moiety has been synthesized and characterized. The chemical, electronic structure and photophysical properties have been studied by spectroscopic analysis abetted with DFT and TDDFT calculations. The change in electronic spectra of HL by titration with aq. NaOH is studied and well supported by TDDFT calculations. The structure is confirmed by single crystal X-ray study. In the unit cell, two HL molecules are H-bonded with H2O molecule and forms dimmeric structure. The molecule forms 2D-supramolecular structure by inter-molecular H-bonding and π-π interactions.

  14. Sarcolemmal phospholipid N-methylation in genetically determined hamster cardiomyopathy

    SciTech Connect

    Okumura, K.; Panagia, V.; Jasmin, G.; Dhalla, N.S.

    1987-02-27

    The heart sarcolemmal phosphatidylethanolamine N-methylation in UM-X7.1 strain of cardiomyopathic hamsters was examined by using 0.055, 10 and 150 microM S-adenosyl-L-(methyl-/sup 3/H) methionine as methyl donor for sites I, II and III, respectively. In comparison with control values, methylation activities at site I was increased in 40, 120 and 250 days old cardiomyopathic hamsters. On the other hand, methylation activities at sites II and III in 120 and 250 days old cardiomyopathic animals were depressed without any change in the 40 days old group. The alterations in N-methylation activities were associated with kinetic changes in apparent Vmax values without any changes in the apparent Km. These results indicate a defect in the phospholipid N-methylation process in heart sarcolemma during the development of genetically determined cardiomyopathy.

  15. ABT-089 [2-methyl-3-(2-(S)-pyrrolidinylmethoxy)pyridine dihydrochloride]: II. A novel cholinergic channel modulator with effects on cognitive performance in rats and monkeys.

    PubMed

    Decker, M W; Bannon, A W; Curzon, P; Gunther, K L; Brioni, J D; Holladay, M W; Lin, N H; Li, Y; Daanen, J F; Buccafusco, J J; Prendergast, M A; Jackson, W J; Arneric, S P

    1997-10-01

    ABT-089 [2-methyl-3-(2-(S)-pyrrolidinylmethoxy)pyridine dihydrochloride], a novel ligand at neuronal nicotinic acetylcholine receptors with reduced adverse effects and improved oral bioavailability relative to (-)-nicotine, was tested in a variety of cognitive tests in rats and monkeys. Administered acutely, ABT-089 only marginally improved the spatial discrimination water maze performance of septal-lesioned rats. However, more robust improvement (45% error reduction on the last training day) was observed when ABT-089 was administered continuously via subcutaneous osmotic pumps (minimum effective dose: 1.3 micromol/kg/day). Continuous infusion of (-)-nicotine produced comparable improvement in the spatial discrimination water maze performance of septal-lesioned rats, but a 40-fold higher dose of (-)-nicotine was required (62 micromol/kg/day). Continuous infusion of ABT-089 to aged rats enhanced spatial learning in a standard Morris water maze, as indexed by spatial bias exhibited during a probe trial conducted after 4 days of training, but not when they were subsequently trained in a two-platform spatial discrimination water maze. The compound induced a small impairment in young rats on the standard water maze, but not on the two-platform task. A probe trial conducted after additional training in the standard water maze revealed no age or drug effects. ABT-089 did not affect performance of either the aged or young rats during inhibitory (passive) avoidance training. Also, continuous infusion of ABT-089 did not affect responses to acoustic startle or prepulse inhibition of acoustic startle in young, aged or septal-lesioned rats and did not affect locomotor activity in either sham-lesioned or septal-lesioned rats. In monkeys, acute administration of ABT-089 modestly improved the delayed matching-to-sample performance of mature, adult monkeys and more robustly improved performance in aged monkeys. Improved performance in the aged monkeys was restricted to the longest

  16. Measurements of mercury methylation rates and bioavailability in the Allequash Creek Wetland, Northern Wisconsin

    NASA Astrophysics Data System (ADS)

    Creswell, J. E.; Babiarz, C. L.; Shafer, M. M.; Armstrong, D. E.

    2008-12-01

    Wetlands are known to be hot spots for the production of methylmercury (MeHg) and subsequent export into other aquatic ecosystems. Because MeHg is a bioaccumulative neurotoxin, and because the primary route of human exposure to mercury is through the consumption of contaminated fish, understanding the processes by which MeHg is produced in the aquatic environment is important to the protection of human health. Inorganic Hg(II) is known to be methylated by bacteria in the anoxic zones of wetland sediments, but bioavailability plays a role in this process, as certain chemical complexes of mercury are unavailable to the microbial community. In the Allequash Creek wetland, a strong relationship has been observed between MeHg and Dissolved Organic Carbon (DOC) concentrations, but the observed relationship between MeHg and total Hg is weak. This observation implicates factors other than Hg(II) concentration as drivers of methylation. In this study, depth-resolved estimates of the bioavailability of inorganic Hg(II) were made by measuring the net mercury methylation rate potential in the hyporheic zone of the wetland. Gross mercury methylation was measured in sediment cores amended with stable isotope-enriched Hg(II), by analyzing isotopically-enriched methylmercury produced during an incubation. Demethylation was measured by amending replicate cores with stable isotope-enriched methylmercury and analyzing the amount consumed over the incubation period. Analyses were conducted using an inductively coupled plasma-quadrupole mass spectrometer. A method comparison was made between incubating cores intact, with mercury amendments injected through core tube walls, and incubating sectioned cores, with mercury amendments mixed into homogenized sediments. The value of incubating intact cores is that disturbance to the sediment and the microbial community is minimized, resulting in experimental conditions that more accurately mimic in situ conditions. The value of mixing mercury

  17. Biological activity of palladium(II) and platinum(II) complexes of the acetone Schiff bases of S-methyl- and S-benzyldithiocarbazate and the X-ray crystal structure of the [Pd(asme)2] (asme=anionic form of the acetone Schiff base of S-methyldithiocarbazate) complex.

    PubMed

    Akbar Ali, Mohammad; Mirza, Aminul Huq; Butcher, Raymond J; Tarafder, M T H; Keat, Tan Boon; Ali, A Manaf

    2002-11-25

    Palladium(II) and platinum(II) complexes of general empirical formula, [M(NS)(2)] (NS=uninegatively charged acetone Schiff bases of S-methyl- and S-benzyldithiocarbazate; M=Pt(II) and Pd(II)) have been prepared and characterized by a variety of physicochemical techniques. Based on conductance, IR and electronic spectral evidence, a square-planar structure is assigned to these complexes. The crystal and molecular structure of the [Pd(asme)(2)] complex (asme=anionic form of the acetone Schiff base of S-methyldithiocarbazate) has been determined by X-ray diffraction. The complex has a distorted cis-square planar structure with the ligands coordinated to the palladium(II) ions as uninegatively charged bidentate NS chelating agents via the azomethine nitrogen and the mercaptide sulfur atoms. The distortion from a regular square-planar geometry is attributed to the restricted bite angles of the ligands. Antimicrobial tests indicate that the Schiff bases exhibit strong activities against the pathogenic bacteria, Bacillus subtilis (mutant defective DNA repair), methicillin-resistant Staphylococcus aureus, B. subtilis (wild type) and Pseudomonas aeruginosa and the fungi, Candida albicans (CA), Candida lypotica (2075), Saccharomyces cerevisiae (20341) and Aspergillus ochraceous (398)-the activities exhibited by these compounds being greater than that of the standard antibacterial and antifungal drugs, streptomycin and nystatin, respectively. The palladium(II) and platinum(II) complexes are inactive against most of these organisms but, the microbe, Pseudomonas aeruginosa shows strong sensitivity to the platinum(II) complexes. Screening of the compounds for their cytotoxicities against T-lymphoblastic leukemia cancer cells has shown that the acetone Schiff base of S-methyldithiocarbazate (Hasme) exhibits a very weak activity, whereas the S-benzyl derivative (Hasbz) is inactive. However, the palladium(II) complexes exhibit strong cytotoxicities against this cancer; their

  18. A new three-dimensional zinc(II) coordination polymer involving 2-[(1H-1,2,4-triazol-1-yl)methyl]-1H-benzimidazole and benzene-1,4-dicarboxylate ligands.

    PubMed

    Jian, Shou Jun; Han, Qian Qian; Yang, Huai Xia; Meng, Xiang Ru

    2016-07-01

    Metal-organic frameworks (MOFs) based on multidentate N-heterocyclic ligands involving imidazole, triazole, tetrazole, benzimidazole, benzotriazole or pyridine present intriguing molecular topologies and have potential applications in ion exchange, magnetism, gas sorption and storage, catalysis, optics and biomedicine. The 2-[(1H-1,2,4-triazol-1-yl)methyl]-1H-benzimidazole (tmb) ligand has four potential N-atom donors and can act in monodentate, chelating, bridging and tridentate coordination modes in the construction of complexes, and can also act as both a hydrogen-bond donor and acceptor. In addition, the tmb ligand can adopt different coordination conformations, resulting in complexes with helical structures due to the presence of the flexible methylene spacer. A new three-dimensional coordination polymer, poly[[bis(μ2-benzene-1,4-dicarboxylato)-κ(4)O(1),O(1'):O(4),O(4');κ(2)O(1):O(4)-bis{μ2-2-[(1H-1,2,4-triazol-1-yl)methyl-κN(4)]-1H-benzimidazole-κN(3)}dizinc(II)] trihydrate], {[Zn(C8H4O4)(C10H9N5)]·1.5H2O}n, has been synthesized by the reaction of ZnCl2 with tmb and benzene-1,4-dicarboxylic acid (H2bdic) under solvothermal conditions. There are two crystallographically distinct bdic(2-) ligands [bdic(2-)(A) and bdic(2-)(B)] in the structure which adopt different coordination modes. The Zn(II) ions are bridged by tmb ligands, leading to one-dimensional helical chains with different handedness, and adjacent helices are linked by bdic(2-)(A) ligands, forming a two-dimensional network structure. The two-dimensional layers are further connected by bdic(2-)(B) ligands, resulting in a three-dimensional framework with the topological notation 6(6). The IR spectra and thermogravimetric curves are consistent with the results of the X-ray crystal structure analysis and the title polymer exhibits good fluorescence in the solid state at room temperature. PMID:27377273

  19. (2,2′-Bipyridyl-κ2 N,N′)bis­(N-butyl-N-methyl­dithio­carbamato-κ2 S,S′)cadmium(II)

    PubMed Central

    Jamaluddin, Nur Amirah; Baba, Ibrahim; Mohamed Tahir, Mohamed Ibrahim; Tiekink, Edward R. T.

    2011-01-01

    The CdII atom in the title compound, [Cd(C6H12NS2)2(C10H8N2)], is hexa­coordinated by two dithio­carbamate ligands and the N atoms from a bidentate 2,2′-bipyridyl mol­ecule. The coordination geometry is based on a distorted trigonal–prismatic arrangement of the N2S4 donor set. Supra­molecular chains, aligned along the a-axis direction, are mediated by C—H⋯S inter­actions and these are connected into layers that stack along the c axis via π–π inter­actions [Cg(pyrid­yl)⋯Cg(pyrid­yl) = 3.6587 (13) Å]. PMID:21522303

  20. Inclusion compounds between α-, β- and γ-cyclodextrins: iron II lactate: a theoretical and experimental study using diffusion coefficients and molecular mechanics

    NASA Astrophysics Data System (ADS)

    Leite, Rosiley A.; Lino, Antonio C. S.; Takahata, Yuji

    2003-01-01

    The inclusion compounds between iron II lactate and three different cyclodextrins (CDs) were studied by means of experimental and theoretical data. The importance of iron II in the human metabolism effort the necessity of a minimum concentration to the human life. Malnutrition is one great problem in social politics of many countries on the world. The possibility to the development of novel medicines with the iron II species stable look for an increase on the efficiency for this kind of aid. Kinetics measurements confirm the possibility to stop the oxidation reaction. It was the first indication of efficient molecular encapsulation. Diffusion coefficient measurements were carried out by Taylor-Aris diffusion technique. The decrease of diffusion coefficients measured for iron II lactate when alone and forming the inclusion complexes was obtained for all hosts molecules used. Molecular Mechanics calculations were performed to elucidate the perfect arrange of iron II lactate inside CDs cavity. No great differences were obtained to the binding energy for the different hosts. Using the software HyperChem6.03v MM+, AMBER94 and OPLS Forced Fields for iron atom in two chemical environments (a) vacuum and (b) with addition of 250 water molecules (MM+). The solvent treatment was decisive to the order of stability. This order was β-CD>γ-CD>α-CD, the same order of solubility in water. The results contained in this work confirm the possibility to protect iron II lactate against oxidation.

  1. Study the Effect of S-Methyl L-Cysteine on Lipid Metabolism in an Experimental Model of Diet Induced Obesity

    PubMed Central

    G.P., Senthilkumar; Thomas, Sithara; K., Sivaraman; Sankar, P.; Bobby, Zachariah

    2013-01-01

    Background: S-methyl L-cysteine (SMC) is a hydrophilic cysteine-containing compound naturally found in Alium plants such as, garlic and onion. Objectives: The present study was aimed to evaluate the hypoglycemic and antihyperlipidemic properties of SMC in high fructose induced diabetic rats. Material and Methods: The present study was designed to evaluate the hypoglycemic and antihyperlipidemic properties of SMC in high fructose induced diabetic rats. Blood samples were collected and the fasting plasma glucose, lipid profile, total antioxidant status (TAS) aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were estimated using standard procedures. Differences between the groups were assessed by using One way Analysis of Variance with (ANOVA) Tukey post hoc test. Results: Oral administration of SMC at a dose of 100 mg/kg bodyweight/day to HFD-treated rats for a period of 60 days showed significant reduction in the animal weight, fasting plasma glucose, total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), VLDL-C and elevation in the level of high-density lipoprotein cholesterol (HDL-C) and TAS compared with fructose fed group. The effects of SMC was compared with metformin; a well-known antihyperglycemic drug. Conclusion: In conclusion, SMC found to be effective in improving the high fructose induced hyperglycemia and dyslipidemia. It may possibly provide a potential adjuvant for the treatment and management of diabetes. PMID:24392369

  2. Inhibition of indoleamine 2,3-dioxygenase by stereoisomers of 1-methyl tryptophan in an experimental graft-versus-tumor model.

    PubMed

    Lim, Ji-Young; Lee, Sung-Eun; Park, Gyenogsin; Choi, Eun Young; Min, Chang-Ki

    2014-10-01

    Indoleamine 2,3-dioxygenase (IDO) is a rate-limiting enzyme in tryptophan catabolism that plays an important role in the induction of immune tolerance. Its role in graft-versus-tumor effect after allogeneic stem cell transplantation (allo-SCT) remains unclear. Using a murine graft-versus-tumor model of reduced-intensity allo-HSCT followed by donor leukocyte infusion (DLI), we examined the role of IDO inhibition. Two stereoisomers of 1-methyl tryptophan (1-MT), a small-molecule inhibitor of IDO, reduced the growth of inoculated tumor in the mice that received DLI and had higher expression of IDO1 and IFNγ. However, L-1MT, but not D-1MT, mitigated tumor growth in mice that did not receive DLI and did not express IDO1 and IFNγ. Accordingly, both stereoisomers reduced plasma kynurenine concentrations early after DLI and enhanced in vitro cytotoxic lymphocyte function after allogeneic mixed lymphocyte reaction. Furthermore, L-1MT was more efficient in causing direct cytotoxic effects than D-1MT. Our results suggest that IDO inhibition can benefit anti-tumor therapy in the setting of reduced-intensity allo-SCT using DLI. PMID:24971697

  3. Crystal structure of a tetranuclear Cu(II) complex with an O,N,N'-donor Schiff base ligand: hexa-μ2-acetato-bis-(2-{[(2,2,6,6-tetra-methyl-piperidin-4-yl)imino]-meth-yl}phenolato-κ(3) O,N,N')tetra-copper(II).

    PubMed

    Huang, Guohui; Liu, Xiaoxuan

    2016-04-01

    The title compound, [Cu4(CH3COO)6(C16H23N2O)2], lies across a twofold rotation axis. The asymmetric unit contains two independent Cu(II) ions. The symmetry-unique terminal Cu(II) ion is O,N,N'-coordinated by a 2-{[(2,2,6,6-tetra-methyl-piperidin-4-yl)imino]-meth-yl}phenolate ligand and an O atom from an acetate group in a slightly distorted square-planar coordination environment. The symmetry-unique central Cu(II) ion is coordinated by a different O atom from the same acetate group and by four bridging acetate ligands, which connect the asymmetric unit into a dimeric complex and form a distorted square-pyramidal coordination environment. Within the complex there are two symmetry-equivalent intra-molecular N-H⋯O hydrogen bonds. In the crystal, weak C-H⋯O hydrogen bonds link the complex mol-ecules, forming a three-dimensional network. PMID:27375896

  4. Crystal structure of a tetranuclear CuII complex with an O,N,N′-donor Schiff base ligand: hexa-μ2-acetato-bis­(2-{[(2,2,6,6-tetra­methyl­piperidin-4-yl)imino]­meth­yl}phenolato-κ3 O,N,N′)tetra­copper(II)

    PubMed Central

    Huang, Guohui; Liu, Xiaoxuan

    2016-01-01

    The title compound, [Cu4(CH3COO)6(C16H23N2O)2], lies across a twofold rotation axis. The asymmetric unit contains two independent CuII ions. The symmetry-unique terminal CuII ion is O,N,N′-coordinated by a 2-{[(2,2,6,6-tetra­methyl­piperidin-4-yl)imino]­meth­yl}phenolate ligand and an O atom from an acetate group in a slightly distorted square-planar coordination environment. The symmetry-unique central CuII ion is coordinated by a different O atom from the same acetate group and by four bridging acetate ligands, which connect the asymmetric unit into a dimeric complex and form a distorted square-pyramidal coordination environment. Within the complex there are two symmetry-equivalent intra­molecular N—H⋯O hydrogen bonds. In the crystal, weak C—H⋯O hydrogen bonds link the complex mol­ecules, forming a three-dimensional network. PMID:27375896

  5. Experimental hut evaluation of bednets treated with an organophosphate (chlorpyrifos-methyl) or a pyrethroid (lambdacyhalothrin) alone and in combination against insecticide-resistant Anopheles gambiae and Culex quinquefasciatus mosquitoes

    PubMed Central

    Asidi, Alex N; N' Guessan, Raphael; Koffi, Alphonsine A; Curtis, Christopher F; Hougard, Jean-Marc; Chandre, Fabrice; Corbel, Vincent; Darriet, Frédéric; Zaim, Morteza; Rowland, Mark W

    2005-01-01

    Background Pyrethroid resistant mosquitoes are becoming increasingly common in parts of Africa. It is important to identify alternative insecticides which, if necessary, could be used to replace or supplement the pyrethroids for use on treated nets. Certain compounds of an earlier generation of insecticides, the organophosphates may have potential as net treatments. Methods Comparative studies of chlorpyrifos-methyl (CM), an organophosphate with low mammalian toxicity, and lambdacyhalothrin (L), a pyrethroid, were conducted in experimental huts in Côte d'Ivoire, West Africa. Anopheles gambiae and Culex quinquefasciatus mosquitoes from the area are resistant to pyrethroids and organophosphates (kdr and insensitive acetylcholinesterase Ace.1R). Several treatments and application rates on intact or holed nets were evaluated, including single treatments, mixtures, and differential wall/ceiling treatments. Results and Conclusion All of the treatments were effective in reducing blood feeding from sleepers under the nets and in killing both species of mosquito, despite the presence of the kdr and Ace.1R genes at high frequency. In most cases, the effects of the various treatments did not differ significantly. Five washes of the nets in soap solution did not reduce the impact of the insecticides on A. gambiae mortality, but did lead to an increase in blood feeding. The three combinations performed no differently from the single insecticide treatments, but the low dose mixture performed encouragingly well indicating that such combinations might be used for controlling insecticide resistant mosquitoes. Mortality of mosquitoes that carried both Ace.1R and Ace.1S genes did not differ significantly from mosquitoes that carried only Ace.1S genes on any of the treated nets, indicating that the Ace.1R allele does not confer effective resistance to chlorpyrifos-methyl under the realistic conditions of an experimental hut. PMID:15918909

  6. Crystal structure of trans-bis­{4-bromo-N-[(pyridin-2-yl)­methyl­idene]aniline-κ2 N,N′}di­chlorido­ruthenium(II)

    PubMed Central

    Chainok, Kittipong; Kielar, Filip

    2015-01-01

    In the title complex, [RuCl2(C12H9BrN2)2] or [RuCl2(PM-BrA)2] (PM-BrA = 4-bromo-N-(2′-pyridyl­methyl­ene)aniline), the RuII cation is located on a centre of inversion and is surrounded by four N atoms of two PM-BrA ligands in the equatorial plane and by two Cl atoms in a trans axial arrangement, displaying a distorted octa­hedral coordination environment. Two C atoms in the benzene ring of the PM-BrA ligand are equally disordered over two sets of sites. The benzene and pyridine rings of the PM-BrA ligand are oriented at dihedral angles of 62.1 (10) and 73.7 (11)° under consideration of the two orientations of the disordered benzene ring. In the crystal, the complex mol­ecules are connected via C—H⋯Cl hydrogen-bonding inter­actions into a layered arrangement parallel (100). C—H⋯Br hydrogen bonding and weak aromatic π–π stacking inter­actions complete a three-dimensional supra­molecular network. PMID:26396850

  7. Synthesis, spectroscopic, crystal structure and DNA binding of Ru(II) complexes with 2-hydroxy-benzoic acid [1-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-ethylidene]-hydrazide

    NASA Astrophysics Data System (ADS)

    Chitrapriya, Nataraj; Sathiya Kamatchi, Thangavel; Zeller, Matthias; Lee, Hyosun; Natarajan, Karuppannan

    2011-10-01

    Reactions of 2-hydroxy-benzoic acid [1-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-ethylidene]-hydrazide (H 2L) with [RuHCl(CO)(EPh 3) 3] (E = P or As) were carried out and the new complexes obtained were characterized by elemental analysis, electronic, IR, 1H NMR and 13C NMR spectroscopic techniques and single crystal X-ray diffraction studies. Complex ( 1) crystallizes in the monoclinic space group P2(1)/ c with unit cell dimensions a = 18.6236(17) Å, b = 12.8627(12) Å, c = 21.683(2) Å, α = 90.00, β = 114.626(2), γ = 90.00 V = 4721.8(8) Å, Z = 4. The crystal structure of the complex shows Ru(II) atom is six-coordinated, forming a slightly distorted octahedral geometry with two P atoms in axial positions, and three chelating donor atoms of the tridentate Schiff base ligand and one carbonyl group located in the equatorial plane. The molecular structure is stabilized by intramolecular O—H···N interactions. No intermolecular hydrogen bond was observed. The intramolecular hydrogen bond exists between the oxygen atom from salicylic acid moiety and nitrogen from the same moiety. A variety of solution studies were carried out for the determination of DNA binding mode of the complexes. The results suggest that both complexes bind to Herring sperm DNA via non intercalative mode.

  8. Cu(II)-mediated atom transfer radical polymerization of methyl methacrylate via a strategy of thermo-regulated phase-separable catalysis in a liquid/liquid biphasic system: homogeneous catalysis, facile heterogeneous separation, and recycling.

    PubMed

    Pan, Jinlong; Zhang, Bingjie; Jiang, Xiaowu; Zhang, Lifen; Cheng, Zhenping; Zhu, Xiulin

    2014-09-01

    A strategy of thermo-regulated phase-separable catalysis (TPSC) is applied to the Cu(II)-mediated atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) in a p-xylene/PEG-200 biphasic system. Initiators for continuous activator regeneration ATRP (ICAR ATRP) are used to establish the TPSC-based ICAR ATRP system using water-soluble TPMA as a ligand, EBPA as an initiator, CuBr2 as a catalyst, and AIBN as a reducing agent. By heating to 70 °C, unlimited miscibility of both solvents is achieved and the polymerization can be carried out under homogeneous conditions; then on cooling to 25 °C, the mixture separates into two phases again. As a result, the catalyst complex remains in the PEG-200 phase while the obtained polymers stay in the p-xylene phase. The catalyst can therefore be removed from the resultant polymers by easily separating the two different layers and can be reused again. It is important that well-defined PMMA with a controlled molecular weight and narrow molecular weight distribution could be obtained using this TPSC-based ICAR ATRP system. PMID:25155655

  9. Di-μ-hydroxido-bis­[hemiaqua­(N,N,N′,N′-tetra­methyl­ethane-1,2-diamine)­copper(II)] bis­(tetra­fluoridoborate)

    PubMed Central

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

    2012-01-01

    The title compound, [Cu2(OH)2(C6H16N2)2(H2O)](BF4)2, consists of dinuclear centrosymmetric [Cu2(OH)2(tmen)2(H2O)]2+ complex cations (tmen = N,N,N′,N′-tetra­methyl­ethane-1,2-diamine) and tetra­fluoridoborate anions. In the cation, the CuII atom shows a slightly distorted square-pyramidal coordination geometry provided by a pair of μ-OH− anions and by the N atoms of a chelate tmen ligand in the basal plane. The apical position is statistically occupied by the O atom of a half-occupancy water mol­ecule. The F atoms of the anion are disordered over three sets of sites with occupancies of 0.598 (9):0.269 (6):0.134 (8). The crystal packing is governed by ionic forces as well as by O—H⋯F hydrogen bonds. PMID:22719335

  10. Bis(2-amino-4-methyl­pyrimidin-3-ium) trans-diaqua­bis­(pyrazine-2,3-di­car­boxylato)cobaltate(II) hexa­hydrate

    PubMed Central

    Eshtiagh-Hosseini, Hossein; Necas, Marek; Alfi, Nafiseh; Mirzaei, Masoud

    2010-01-01

    In the crystal structure of the mononuclear title compound, (C5H8N3)2[Co(C6H2N2O4)2(H2O)2]·6H2O or (ampymH)2[Co(pyzdc)2(H2O)2]·6H2O (ampym = 2-amino-4-methyl pyrimidine, pyzdcH2 = pyrazine-2,3-dicarb­oxy­lic acid), the CoII ion is hexa­coordinated by two (pyzdc)2− groups in the equatorial plane and two water mol­ecules in axial positions, giving an N2CoO4 bound set. The (pyzdc)2− anion acts as a bidentate ligand through one carboxyl­ate group O atom and pyrazine ring N atom. There are diverse N—H⋯ O and O—H⋯O and O—H⋯N hydrogen-bonding inter­actions, which lead to the formation of a three-dimensional supra­molecular architecture. Off-set or slipped π–π stacking inter­actions are also observed between adjacent pyrimidine rings with face-to-face distances of 3.6337 (9) Å. PMID:21587454

  11. Ethyl­enediammonium tetra­kis({2,2′-[ethane-1,2-diylbis(nitrilo­methyl­idyne)]diphenolato}nickel(II)) bis­(perchlorate) dimethyl­formamide monosolvate

    PubMed Central

    Assey, Gervas; Gultneh, Yilma; Butcher, Ray J.

    2010-01-01

    The title compound, (C2H10N2)[Ni(C16H14N2O2)]4(ClO4)2·C3H7NO, crystallizes with four Ni(salen) mol­ecules {salen is 2,2′-[ethane-1,2-diylbis(nitrilo­methyl­idyne)]diphenolate}, one ethyl­enediammonium cation (actually two half-cations, each located on a center of inversion), two perchlorate anions and one dimethyl­formamide solvent mol­ecule in the asymmetric unit. Each NiII cation in the Ni(salen) complex is four-coordinated by two imine N atoms and two phenolate O atoms from the tetra­dentate ligand. The Ni(salen) units form parallel slipped stacks with Ni⋯Ni separations of 3.4541 (4) and 3.6442 (6) Å. The crystal packing is stabilized by inter­molecular hydrogen bonds between the ammonium H atoms and the perchlorate and salen O atoms, which generate a three-dimensional structure. PMID:21579300

  12. Effects of captopril, telmisartan and bardoxolone methyl (CDDO-Me) in ischemia-reperfusion-induced acute kidney injury in rats: an experimental comparative study.

    PubMed

    Kocak, Cengiz; Kocak, Fatma Emel; Akcilar, Raziye; Bayat, Zeynep; Aras, Bekir; Metineren, Mehmet Huseyin; Yucel, Mehmet; Simsek, Hasan

    2016-02-01

    Renal ischemia-reperfusion (IR) injury is one of the most common causes of acute kidney injury. This study investigated the effects of captopril (CAP), telmisartan (TEL) and bardoxolone methyl (BM) in animals with renal IR injury. Adult male Wistar-Albino rats were divided into six groups: control, vehicle, IR, IR with CAP, IR with TEL and IR with BM. Before IR was induced, drugs were administered by oral gavage. After a 60-min ischemia and a 120-min reperfusion period, bilateral nephrectomies were performed. Serum urea, creatinine, neutrophil gelatinase-associated lipocalin (NGAL) levels, tissue total oxidant status (TOS), total antioxidant status (TAS), total thiol (TT), asymmetric dimethylarginine (ADMA) levels, superoxide dismutase (SOD) activity and glutathione peroxidase (GSH-Px) activity were measured. Tissue mRNA expression levels of peroxisome proliferator-activated receptor-ɣ (PPAR-ɣ), nuclear factor erythroid 2-related factor 2 (Nrf2) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) were analyzed. In addition, renal tissues were evaluated histopathologically and immunohistochemically. All tested drugs reduced renal damage, apoptosis, urea, creatinine, NGAL, TOS, nitric oxide (NO) and ADMA levels, NF-κB, inducible nitric oxide synthase (iNOS) and endothelin-1 (ET-1) expressions (P < 0.001). All tested drugs increased SOD activity, GSH-Px activity, TAS levels, TT levels, endothelial nitric oxide synthase (eNOS) expression, dimethylarginine dimethylaminohydrolases (DDAHs) expression, Nrf2 expression and PPAR-ɣ expression (P < 0.001, P < 0.003). These results suggest that CAP, TEL and BM pretreatment could reduce renal IR injury via anti-inflammatory, antioxidant and anti-apoptotic effects. PMID:26515498

  13. A combined experimental and theoretical investigation of a new imineoxime and its palladium(II) and platinum(II) complexes: Synthesis, structural characterization and spectroscopic properties

    NASA Astrophysics Data System (ADS)

    Kaya, Yunus; Icsel, Ceyda; Yilmaz, Veysel T.; Buyukgungor, Orhan

    2014-12-01

    A new imineoxime compound {(1E,2E)-(2-hydroxy-ethylimino)-naphthalene-2yl-ethanal oxime (heineoH)} and its palladium(II) and platinum(II) complexes ([M(heineo)2]) have been synthesized and characterized by IR, NMR, UV-vis, elemental analysis, mass spectra and X-ray single crystal diffraction. [Pt(heineo)2] was obtained as a single crystal, while [Pd(heineo)2] was synthesized as a polycrystalline powder. The X-ray diffraction analysis of the [Pt(heineo)2] indicated that the platinum(II) ion is coordinated by two heineo ligands in a distorted square-planar geometry. DFT (B3LYP/6-311++G(d,p) and LANL2DZ) calculations on the ligand and its complexes were carried out to correlate the geometry and vibrational and electronic properties. Additionally, heineoH is fluorescent in EtOH at room temperature, but the fluorescence is quenched in the case of the metal complexes.

  14. A combined experimental and theoretical investigation of a new imineoxime and its palladium(II) and platinum(II) complexes: synthesis, structural characterization and spectroscopic properties.

    PubMed

    Kaya, Yunus; Icsel, Ceyda; Yilmaz, Veysel T; Buyukgungor, Orhan

    2014-12-10

    A new imineoxime compound {(1E,2E)-(2-hydroxy-ethylimino)-naphthalene-2yl-ethanal oxime (heineoH)} and its palladium(II) and platinum(II) complexes ([M(heineo)2]) have been synthesized and characterized by IR, NMR, UV-vis, elemental analysis, mass spectra and X-ray single crystal diffraction. [Pt(heineo)2] was obtained as a single crystal, while [Pd(heineo)2] was synthesized as a polycrystalline powder. The X-ray diffraction analysis of the [Pt(heineo)2] indicated that the platinum(II) ion is coordinated by two heineo ligands in a distorted square-planar geometry. DFT (B3LYP/6-311++G(d,p) and LANL2DZ) calculations on the ligand and its complexes were carried out to correlate the geometry and vibrational and electronic properties. Additionally, heineoH is fluorescent in EtOH at room temperature, but the fluorescence is quenched in the case of the metal complexes. PMID:24929321

  15. Phosphatase Rtr1 Regulates Global Levels of Serine 5 RNA Polymerase II C-Terminal Domain Phosphorylation and Cotranscriptional Histone Methylation.

    PubMed

    Hunter, Gerald O; Fox, Melanie J; Smith-Kinnaman, Whitney R; Gogol, Madelaine; Fleharty, Brian; Mosley, Amber L

    2016-09-01

    In eukaryotes, the C-terminal domain (CTD) of Rpb1 contains a heptapeptide repeat sequence of (Y1S2P3T4S5P6S7)n that undergoes reversible phosphorylation through the opposing action of kinases and phosphatases. Rtr1 is a conserved protein that colocalizes with RNA polymerase II (RNAPII) and has been shown to be important for the transition from elongation to termination during transcription by removing RNAPII CTD serine 5 phosphorylation (Ser5-P) at a selection of target genes. In this study, we show that Rtr1 is a global regulator of the CTD code with deletion of RTR1 causing genome-wide changes in Ser5-P CTD phosphorylation and cotranscriptional histone H3 lysine 36 trimethylation (H3K36me3). Using chromatin immunoprecipitation and high-resolution microarrays, we show that RTR1 deletion results in global changes in RNAPII Ser5-P levels on genes with different lengths and transcription rates consistent with its role as a CTD phosphatase. Although Ser5-P levels increase, the overall occupancy of RNAPII either decreases or stays the same in the absence of RTR1 Additionally, the loss of Rtr1 in vivo leads to increases in H3K36me3 levels genome-wide, while total histone H3 levels remain relatively constant within coding regions. Overall, these findings suggest that Rtr1 regulates H3K36me3 levels through changes in the number of binding sites for the histone methyltransferase Set2, thereby influencing both the CTD and histone codes. PMID:27247267

  16. Combined Theoretical and Experimental Study of Spin and Charge Dynamics on the Homodinuclear Complex [Ni2II(L-N4Me2)(emb)

    NASA Astrophysics Data System (ADS)

    Jin, W.; Rupp, F.; Chevalier, K.; Wolf, M. M. N.; Rojas, M. Colindres; Lefkidis, G.; Krüger, H.-J.; Diller, R.; Hübner, W.

    2012-12-01

    We present a combined theoretical and experimental study of spin and charge dynamics on the homodinuclear compound [Ni2II(L-N4Me2)(emb)]. The theoretically calculated oscillator strengths of the ground-state absorption spectrum show an acceptable agreement with experiment. We predict a local ultrafast laser-induced spin-flip scenario, which involves charge-transfer states. Experimentally, we observe charge dynamics on two different time scales. The two relevant, transient electronic states and their electronic properties are also theoretically characterized. These results provide a joint investigation of the homodinuclear complex and suggest a realistic scenario for ultrafast spin dynamics and other optical-related manipulations.

  17. The origins of atmospheric methyl mercury

    SciTech Connect

    Prestbo, E.M.; Bloom, N.S.

    1995-12-31

    Methyl Hg in precipitation shows strong regional patterns, with highest volume weighted mean values (0.4 ng/L) in the Pacific Northwest and lowest values in Florida (<0.01 ng/l). Over most of the North Central region, average values range from 0.05 to 0.2 ng/L. Several potential sources of methyl Hg to the atmosphere have been investigated, including direct anthropogenic emissions, atmospheric methylation of Hg{sup o} or Hg(II), and emissions of methyl or dimethyl Hg from natural surfaces (oceans, bogs, or forests). Direct measurements of major total Hg sources such as coal and waste combustors, and sewage treatment facilities suggest that direct anthropogenic emissions are an insignificant source of methyl Hg to the atmosphere. The gas phase reaction of methyl halides with Hg{sup o} also appears to be an insignificant source of methyl Hg to the atmosphere. Recent laboratory experiments have provided a likely mechanism for atmospheric Hg methylation via a complex reaction involving acetate, sulfite, and iron. From a series of field measurements, another source appears to be the degradation of dimethyl mercury emitted by the upwelling of deep ocean water.

  18. Synthesis, crystal structure, spectroscopic characterization and nonlinear optical properties of manganese (II) complex of picolinate: A combined experimental and computational study

    NASA Astrophysics Data System (ADS)

    Tamer, Ömer; Avcı, Davut; Atalay, Yusuf; Çoşut, Bünyemin; Zorlu, Yunus; Erkovan, Mustafa; Yerli, Yusuf

    2016-02-01

    A novel manganese (II) complex with picolinic acid (pyridine 2-carboxylic acid, Hpic), namely, [Mn(pic)2(H2O)2] was prepared and its crystal structure was fully characterized by using single crystal X-ray diffraction. Picolinate (pic) ligands were coordinated to the central manganese(II) ion as bidentate N,O-donors through the nitrogen atoms of pyridine rings and the oxygen atoms of carboxylate groups forming five-membered chelate rings. The spectroscopic characterization of Mn(II) complex was performed by the applications of FT-IR, Raman, UV-vis and EPR techniques. In order to support these studies, density functional theory (DFT) calculations were carried out by using B3LYP level. IR and Raman spectra were simulated at B3LYP level, and obtained results indicated that DFT calculations generally give compatible results to the experimental ones. The electronic structure of the Mn(II) complex was predicted using time dependent DFT (TD-DFT) method with polarizable continuum model (PCM). Molecular stability, hyperconjugative interactions, intramolecular charge transfer (ICT) and bond strength were investigated by applying natural bond orbital (NBO) analysis. Nonlinear optical properties of Mn(II) complex were investigated by the determining of molecular polarizability (α) and hyperpolarizability (β) parameters.

  19. 1-[N, O-bis-(5-isoquinolinesulphonyl)-N-methyl-L-tyrosyl]-4- phenylpiperazine (KN-62), an inhibitor of calcium-dependent camodulin protein kinase II, inhibits both insulin- and hypoxia-stimulated glucose transport in skeletal muscle.

    PubMed Central

    Brozinick, J T; Reynolds, T H; Dean, D; Cartee, G; Cushman, S W

    1999-01-01

    Previous studies have indicated a role for calmodulin in hypoxia-and insulin-stimulated glucose transport. However, since calmodulin interacts with multiple protein targets, it is unknown which of these targets is involved in the regulation of glucose transport. In the present study, we have used the calcium-dependent calmodulin protein kinase II (CAMKII) inhibitor 1-[N, O-bis-(5-isoquinolinesulphonyl) -N-methyl-L-tyrosyl]-4-phenylpiperazine (KN-62) to investigate the possible role of this enzyme in the regulation of glucose transport in isolated rat soleus and epitrochlearis muscles. KN-62 did not affect basal 2-deoxyglucose transport, but it did inhibit both insulin- and hypoxia-stimulated glucose transport activity by 46 and 40% respectively. 1-[N,O-Bis-(1, 5-isoquinolinesulphonyl)-N-methyl-l-tyrosyl]-4-phenylpiperazine (KN-04), a structural analogue of KN-62 that does not inhibit CAMKII, had no effect on hypoxia-or insulin-stimulated glucose transport. Accordingly, KN-62 decreased the stimulated cell-surface GLUT4 labelling by a similar extent as the inhibition of glucose transport (insulin, 49% and hypoxia, 54%). Additional experiments showed that KN-62 also inhibited insulin- and hypoxia-stimulated transport by 37 and 40% respectively in isolated rat epitrochlearis (a fast-twitch muscle), indicating that the effect of KN-62 was not limited to the slow-twitch fibres of the soleus. The inhibitory effect of KN-62 on hypoxia-stimulated glucose transport appears to be specific to CAMKII, since KN-62 did not inhibit hypoxia-stimulated 45Ca efflux from muscles pre-loaded with 45Ca, or hypoxia-stimulated glycogen breakdown. Additionally, KN-62 affected neither insulin-stimulated phosphoinositide 3-kinase nor Akt activity, suggesting that the effects of KN-62 are not due to non-specific effects of this inhibitor on these regions of the insulin-signalling cascade. The results of the present study suggest that CAMKII might have a distinct role in insulin- and hypoxia

  20. Experimental and quantum-chemical studies of 1H, 13C and 15N NMR coordination shifts in Au(III), Pd(II) and Pt(II) chloride complexes with picolines.

    PubMed

    Pazderski, Leszek; Tousek, Jaromír; Sitkowski, Jerzy; Malináková, Katerina; Kozerski, Lech; Szłyk, Edward

    2009-03-01

    (1)H, (13)C and (15)N NMR studies of gold(III), palladium(II) and platinum(II) chloride complexes with picolines, [Au(PIC)Cl(3)], trans-[Pd(PIC)(2)Cl(2)], trans/cis-[Pt(PIC)(2)Cl(2)] and [Pt(PIC)(4)]Cl(2), were performed. After complexation, the (1)H and (13)C signals were shifted to higher frequency, whereas the (15)N ones to lower (by ca 80-110 ppm), with respect to the free ligands. The (15)N shielding phenomenon was enhanced in the series [Au(PIC)Cl(3)] < trans-[Pd(PIC)(2)Cl(2)] < cis-[Pt(PIC)(2)Cl(2)] < trans-[Pt(PIC)(2)Cl(2)]; it increased following the Pd(II) --> Pt(II) replacement, but decreased upon the trans --> cis-transition. Experimental (1)H, (13)C and (15)N NMR chemical shifts were compared to those quantum-chemically calculated by B3LYP/LanL2DZ + 6-31G**//B3LYP/LanL2DZ + 6-31G*. PMID:19097135

  1. Inhibition of NR2B-Containing N-methyl-D-Aspartate Receptors (NMDARs) in Experimental Autoimmune Encephalomyelitis, a Model of Multiple Sclerosis

    PubMed Central

    Farjam, Mojtaba; Beigi Zarandi, Faegheh Baha'addini; Farjadian, Shirin; Geramizadeh, Bita; Nikseresht, Ali Reza; Panjehshahin, Mohammad Reza

    2014-01-01

    Neurodegeneration is the pathophysiological basis for permanent neurological disabilities in multiple sclerosis (MS); thus neuroprotection is emerging as a therapeutic approach in MS research. Modulation of excitotoxicity by inhibition of NMDARs has been suggested for neuroprotection, but selective antagonisation of the NR2B subtype of these receptors, a subtype believed to play a more pivotal role in neurodegeneration, has not been tested in MS. In this study inhibition of NR2B-containing NMDAR was evaluated on the animal model of MS, experimental autoimmune encephalomyelitis (EAE). EAE induction was done using MOG in C57BL/6 mice. Therapeutic administration of different doses of highly selective NR2B-containing NMDAR inhibitor (RO25-6981) was compared with memantine (non-selective NMDAR antagonist) and vehicle. Neurological deficits in EAE animals were more efficiently decreased by selective inhibition of NR2B-containing NMDARs. Histological studies of the spinal cords also showed decreased inflammation, myelin degradation and neuro-axonal degeneration when RO25-6981was administered with higher doses. The effects were dose dependent. Regarding the role of NR2B-containing NMDARs in excitotoxicity, selective inhibition of these receptor subtypes seems to modulate the neurological disabilities and pathological changes in EAE. Further elucidation of the exact mechanism of action as well as more experimental studies can suggest NR2B-containing NMDAR inhibition as a potentially effective treatment strategy for slowing down the clinical deterioration of disability in MS. PMID:25237366

  2. Methyl salicylate overdose

    MedlinePlus

    Methyl salicylate (oil of wintergreen) is a chemical that smells like wintergreen. It is used in many over- ... muscle ache creams. It is related to aspirin. Methyl salicylate overdose occurs when someone swallows a dangerous amount ...

  3. Crystal structure of bis(bis{(E)-[(6-{(E)-[(4-fluorobenzyl)imino]methyl}pyridin-2-yl)methylidene](4-fluorophenyl)amine}nickel(II)) tetra­bromide nona­hydrate

    PubMed Central

    Basaran, Ismet; Rhaman, Md Mhahabubur; Powell, Douglas R.; Hossain, Md. Alamgir

    2015-01-01

    In the title complex, [Ni(C21H17F2N3)2]2Br4·9H2O, there are two independent metal complexes per asymmetric unit and two ligands per metal complex. The structural features (bond lengths and angles) of the two complexes are almost identical. In each complex, the nickel(II) ion is coordinated in an octa­hedral environment by six N atoms from two chelating (9E)-N-({6-[(E)-(4-fluoro­benzyl­imino)­meth­yl]pyridin-2-yl}methyl­ene)(4-fluoro­phen­yl)methanammine ligands. The Ni—N bond lengths range from 1.973 (2) to 2.169 (2) Å, while the chelate N—Ni—N angles range from 77.01 (10) to 105.89 (9)°. Additionally, there are four bromide anions and nine solvent water mol­ecules within the asymmetric unit. The water mol­ecules form a hydrogen-bonded network, displaying C—H⋯O, C—H⋯Br, O—H⋯Br, O—H⋯O and O—H⋯F inter­actions into layers parallel to (111). In each unit, the fluoro­phenyl rings of one ligand are stacked with the central ring of the other ligand via π–π inter­actions, with the closest centroid-to-plane distances being 3.445 (5), 3.636 (5), 3.397 (5) and 3.396 (5) Å. PMID:26870437

  4. Crystal structure of bis(bis{(E)-[(6-{(E)-[(4-fluorobenzyl)imino]methyl}pyridin-2-yl)methylidene](4-fluorophenyl)amine}nickel(II)) tetra-bromide nona-hydrate.

    PubMed

    Basaran, Ismet; Rhaman, Md Mhahabubur; Powell, Douglas R; Hossain, Md Alamgir

    2015-12-01

    In the title complex, [Ni(C21H17F2N3)2]2Br4·9H2O, there are two independent metal complexes per asymmetric unit and two ligands per metal complex. The structural features (bond lengths and angles) of the two complexes are almost identical. In each complex, the nickel(II) ion is coordinated in an octa-hedral environment by six N atoms from two chelating (9E)-N-({6-[(E)-(4-fluoro-benzyl-imino)-meth-yl]pyridin-2-yl}methyl-ene)(4-fluoro-phen-yl)methanammine ligands. The Ni-N bond lengths range from 1.973 (2) to 2.169 (2) Å, while the chelate N-Ni-N angles range from 77.01 (10) to 105.89 (9)°. Additionally, there are four bromide anions and nine solvent water mol-ecules within the asymmetric unit. The water mol-ecules form a hydrogen-bonded network, displaying C-H⋯O, C-H⋯Br, O-H⋯Br, O-H⋯O and O-H⋯F inter-actions into layers parallel to (111). In each unit, the fluoro-phenyl rings of one ligand are stacked with the central ring of the other ligand via π-π inter-actions, with the closest centroid-to-plane distances being 3.445 (5), 3.636 (5), 3.397 (5) and 3.396 (5) Å. PMID:26870437

  5. Experimental analysis and mathematical prediction of Cd(II) removal by biosorption using support vector machines and genetic algorithms.

    PubMed

    Hlihor, Raluca Maria; Diaconu, Mariana; Leon, Florin; Curteanu, Silvia; Tavares, Teresa; Gavrilescu, Maria

    2015-05-25

    We investigated the bioremoval of Cd(II) in batch mode, using dead and living biomass of Trichoderma viride. Kinetic studies revealed three distinct stages of the biosorption process. The pseudo-second order model and the Langmuir model described well the kinetics and equilibrium of the biosorption process, with a determination coefficient, R(2)>0.99. The value of the mean free energy of adsorption, E, is less than 16 kJ/mol at 25 °C, suggesting that, at low temperature, the dominant process involved in Cd(II) biosorption by dead T. viride is the chemical ion-exchange. With the temperature increasing to 40-50 °C, E values are above 16 kJ/mol, showing that the particle diffusion mechanism could play an important role in Cd(II) biosorption. The studies on T. viride growth in Cd(II) solutions and its bioaccumulation performance showed that the living biomass was able to bioaccumulate 100% Cd(II) from a 50 mg/L solution at pH 6.0. The influence of pH, biomass dosage, metal concentration, contact time and temperature on the bioremoval efficiency was evaluated to further assess the biosorption capability of the dead biosorbent. These complex influences were correlated by means of a modeling procedure consisting in data driven approach in which the principles of artificial intelligence were applied with the help of support vector machines (SVM), combined with genetic algorithms (GA). According to our data, the optimal working conditions for the removal of 98.91% Cd(II) by T. viride were found for an aqueous solution containing 26.11 mg/L Cd(II) as follows: pH 6.0, contact time of 3833 min, 8 g/L biosorbent, temperature 46.5 °C. The complete characterization of bioremoval parameters indicates that T. viride is an excellent material to treat wastewater containing low concentrations of metal. PMID:25224921

  6. A combined experimental and theoretical study of the tautomeric and conformational properties of (5-phenyl-tetrazol-2-yl)-acetic acid methyl ester.

    PubMed

    Saeed, Aamer; Qasim, Muhammad; Hussain, Majid; Flörke, Ulrich; Erben, Mauricio F

    2015-11-01

    The tautomeric and conformational properties of a new tetrazole derivative are studied in a combined approach that includes the analysis of the experimental vibrational data together with theoretical calculation methods, especially in terms of natural bond orbital (NBO) population analysis. Moreover, the molecular and crystal structure was determined by single crystal X-ray diffraction. The compound crystallized as the 2-tautomeric form, monoclinic space group P21/c with Z=4, a=10.0630(14), b=8.2879(11), c=12.8375(18) Å, β=105.546(3)°, V=1031.5(2) Å(3). The tetrazole and phenyl rings are coplanar with the acetate group oriented perpendicular to the plane. The NBO analysis showed that delocalizing interactions of the lpp(N2) lone pair orbital contributes to a strong resonance interactions with both adjacent π(∗)(N3N4) and π(∗)(N1C5) antibonding orbitals of the tetrazole group. PMID:26005846

  7. Unique mononuclear Mn(II) complexes of an end-off compartmental Schiff base ligand: experimental and theoretical studies on their bio-relevant catalytic promiscuity.

    PubMed

    Adhikary, Jaydeep; Chakraborty, Aratrika; Dasgupta, Sanchari; Chattopadhyay, Shyamal Kumar; Kruszynski, Rafał; Trzesowska-Kruszynska, Agata; Stepanović, Stepan; Gruden-Pavlović, Maja; Swart, Marcel; Das, Debasis

    2016-08-01

    Three new mononuclear manganese(ii) complexes, namely [Mn(HL)2]·2ClO4 (1), [Mn(HL)(N(CN)2)(H2O)2]·ClO4 (2) and [Mn(HL)(SCN)2] (3) [LH = 4-tert-butyl-2,6-bis-[(2-pyridin-2-yl-ethylimino)-methyl]-phenol], have been synthesized and structurally characterized. An "end-off" compartmental ligand (LH) possesses two symmetrical compartments with N2O binding sites but accommodates only one manganese atom instead of two due to the protonation of the imine nitrogen of one compartment. Although all three complexes are mononuclear, complex 1 is unique as it has a 1 : 2 metal to ligand stoichiometry. The catalytic promiscuity of complexes 1-3 in terms of two different bio-relevant catalytic activities namely catecholase and phenoxazinone synthase has been thoroughly investigated. EPR and cyclic voltametric studies reveal that radical formation rather than metal centered redox participation is responsible for their catecholase-like and phenoxazinone synthase-like catalytic activity. A computational approach suggests that imine bond bound radical generation rather than phenoxo radical formation is most likely responsible for the oxidizing properties of the complexes. PMID:27430642

  8. Techniques in protein methylation.

    PubMed

    Lee, Jaeho; Cheng, Donghang; Bedford, Mark T

    2004-01-01

    Proteins can be methylated on the side-chain nitrogens of arginine and lysine residues or on carboxy-termini. Protein methylation is a way of subtly changing the primary sequence of a peptide so that it can encode more information. This common posttranslational modification is implicated in the regulation of a variety of processes including protein trafficking, transcription and protein-protein interactions. In this chapter, we will use the arginine methyltransferases to illustrate different approaches that have been developed to assess protein methylation. Both in vivo and in vitro methylation techniques are described, and the use of small molecule inhibitors of protein methylation will be demonstrated. PMID:15173617

  9. Water Column Methylation in Estuaries

    NASA Astrophysics Data System (ADS)

    Schartup, A. T.; Calder, R.; Soerensen, A. L.; Mason, R. P.; Balcom, P. H.; Sunderland, E. M.

    2014-12-01

    Methylmercury (MeHg) is a neurotoxin that bioaccumulates in aquatic food webs and affects humans and wildlife through fish consumption. Many studies have measured active methylation/demethylation in ocean margin sediments but few have reported similar rates for the marine water column. This presentation will review available evidence for water column methylation in estuaries, including new experimental measurements of methylation/demethylation rates from a deep subarctic fjord in Labrador Canada collected in Spring and Fall of 2012-2013. We used these and other data to construct a mass budget for MeHg in the estuary and show that water column methylation (with rates ranging from 1.5 to 2.8 % day-1), is the largest contributor, followed by inputs from rivers (4.9 mol year-1), to the in situ pool of MeHg available for uptake by biota. By contrast, the sediment in this system is a net sink for MeHg (-1.5 mol year-1). We discuss the relationship between observed MeHg and other ancillary environmental factors (organic carbon, sulfur and nutrients) as well as implications for the response time of fish to future changes in mercury inputs.

  10. Stability hierarchy between Piracetam forms I, II, and III from experimental pressure-temperature diagrams and topological inferences.

    PubMed

    Toscani, Siro; Céolin, René; Minassian, Léon Ter; Barrio, Maria; Veglio, Nestor; Tamarit, Josep-Lluis; Louër, Daniel; Rietveld, Ivo B

    2016-01-30

    The trimorphism of the active pharmaceutical ingredient piracetam is a famous case of polymorphism that has been frequently revisited by many researchers. The phase relationships between forms I, II, and III were ambiguous because they seemed to depend on the heating rate of the DSC and on the history of the samples or they have not been observed at all (equilibrium II-III). In the present paper, piezo-thermal analysis and high-pressure differential thermal analysis have been used to elucidate the positions of the different solid-solid and solid-liquid equilibria. The phase diagram, involving the three solid phases, the liquid phase and the vapor phase, has been constructed. It has been shown that form III is the high-pressure, low-temperature form and the stable form at room temperature. Form II is stable under intermediary conditions and form I is the low pressure, high temperature form, which possesses a stable melting point. The present paper demonstrates the strength of the topological approach based on the Clapeyron equation and the alternation rule when combined with high-pressure measurements. PMID:26617316

  11. Using the Correlation Dimension for Vibration Fault Diagnosis of Rolling Element BEARINGS—II. Selection of Experimental Parameters

    NASA Astrophysics Data System (ADS)

    Logan, David B.; Mathew, Joseph

    1996-05-01

    Determination of the correlation dimension from experimental chaotic time series data involves two steps. First, reconstruction of the attractor using the time delay method from the raw time series, followed by computation of the correlation dimension from the phase space vectors. We demonstrate how this process has been performed experimentally on bearing vibration acceleration times series. The effects on the correlation dimension were noted as each of the relevant parameters was individually varied and the optimum values for each determined.

  12. Structural, spectroscopic and redox properties of a mononuclear Co(II) thiolate complex--the reactivity toward S-alkylation: an experimental and theoretical study.

    PubMed

    Gennari, Marcello; Gerey, Bertrand; Hall, Nikita; Pécaut, Jacques; Vezin, Hervé; Collomb, Marie-Noëlle; Orio, Maylis; Duboc, Carole

    2012-10-28

    The structural, spectroscopic, redox properties and also the reactivity toward S-alkylation of a new mononuclear N2S2 dithiolate Co(II) complex [CoL] (1), with H(2)L = 2,2'-(2,2'-bipyridine-6,6'-diyl)bis(1,1-diphenylethanethiol), have been investigated. The X-ray structure of 1 has revealed an unusual distorted square planar geometry for a Co(II) ion within a thiolate environment. The X-band EPR spectrum of displays a rhombic S = 1/2 signal consistent with a low spin configuration for the d(7) Co(II) ion with a large g-anisotropy (g(x) = 2.94, g(y) = 2.32 and g(z) = 2.01). By pulsed EPR experiments (HYSCORE), two weak hyperfine couplings (hfc) of 3.2 and 2.2 MHz have been measured and attributed respectively to protons and nitrogen nuclei of the bipyridine unit. In addition, another hyperfine coupling (hfc) of 7.5 MHz has been attributed to the cobalt ion. DFT calculations have successfully reproduced the (59)Co and (14)N hfc parameters. However, multiconfigurational ab initio calculations were required to predict the g-tensor of 1. The cyclic voltammogram (CV) displays two one-electron metal based processes: a quasi-reversible Co(III)/Co(II) oxidation wave at E(1/2) = -0.5 V vs. Fc(+)/Fc and a quasi-reversible Co(II)/Co(I) reduction wave at E(1/2) = -1.7 V. 1 reacts with CH(3)I, generating the mono S-methylated complex, [CoL(Me)I] (1(Me)). The X-band EPR spectrum of 1(Me) displays a typical signal of a high spin (S = 3/2) Co(II) species. An optimized structure of 1(Me), calculated by DFT, is consistent with its EPR and UV-visible spectra. Time dependent density functional theory (TD-DFT) calculations attribute the most prominent features observed in the electronic absorption spectra of 1 and 1(Me). The singly occupied MO (SOMO) of 1 shows a notable delocalization of the unpaired electron over the metal (85%) and the ligand, especially over the sulphur atoms (10.5%), indicating a certain degree of covalency for the Co-S bonds. In 1(Me), for two of the three SOMOs

  13. Comparison of new experimental and atrophysical f-values for some Ru II lines, observed in HST spectra of chi Lupi

    NASA Technical Reports Server (NTRS)

    Johansson, Sveneric G.; Joueizadeh, Ali; Litzen, Ulf; Larsson, Jorgen; Persson, Anders; Wahlstrom, Claes-Goran; Svanberg, Sune; Leckrone, David S.; Wahlgren, Glenn M.

    1994-01-01

    We report an experimental absolute oscillator strengths for 18 UV lines of Ru II, obtained by combining laser-induced flourescence measurements of radiative lifetimes and branching fractions from line intensities in a calibrated Fourier-transform spectrum Hubble Space Telescope/Goddard High Resolution Spectrograph (HST/GHRS) observations of the spectrum of the sharp-lined B star chi Lupi contain six of these lines, for which 'astrophysical' relative f-values have been determined. The agreement is within 0.10 dex for a Ru abundance of log N(Ru)/N(H) = -7.90, which is 2.3 dex above the solar abundance.

  14. Syphilis and human experimentation from the first appearance of the disease to World War II: a historical perspective and reflections on ethics.

    PubMed

    Cuerda-Galindo, E; Sierra-Valentí, X; González-López, E; López-Muñoz, F

    2014-10-01

    Physicians have conducted research on syphilis for centuries, seeking to understand its etiology and the means of transmission as well as find ways to prevent and cure the disease. Their research practices often strayed from today's ethical standards. In this paper we review ethical aspects of the long history of research on syphilis with emphasis on the experiments performed in the 20th century. The description of research around the time of World War II covers medical experiments carried out in US prisons and in the experimentation centers established by Japanese doctors in occupied territory, as well as experiments in Nazi Germany and the treatment of syphilitics there. PMID:24268559

  15. Experimental diabetes increases insulin-like growth factor I and II receptor concentration and gene expression in kidney

    SciTech Connect

    Werner, H.; Shen-Orr, Z.; Stannard, B.; Burguera, B.; Roberts, C.T. Jr.; LeRoith, D. )

    1990-12-01

    Insulinlike growth factor I (IGF-I) is a mitogenic hormone with important regulatory roles in growth and development. One of the target organs for IGF-I action is the kidney, which synthesizes abundant IGF-I receptors and IGF-I itself. To study the involvement of IGF-I and the IGF-I receptor in the development of nephropathy, one of the major complications of diabetes mellitus, we measured the expression of these genes in the kidney and in other tissues of the streptozocin-induced diabetic rat. The binding of 125I-labeled IGF-I to crude membranes was measured in the same tissues. We observed a 2.5-fold increase in the steady-state level of IGF-I-receptor mRNA in the diabetic kidney, which was accompanied by a 2.3-fold increase in IGF-I binding. In addition to this increase in IGF-I binding to the IGF-I receptor, there was also binding to a lower-molecular-weight material that may represent an IGF-binding protein. No change was detected in the level of IGF-I-peptide mRNA. Similarly, IGF-II-receptor mRNA levels and IGF-II binding were significantly increased in the diabetic kidney. IGF-I- and IGF-II-receptor mRNA levels and IGF-I and IGF-II binding returned to control values after insulin treatment. Because the IGF-I receptor is able to transduce mitogenic signals on activation of its tyrosine kinase domain, we hypothesize that, among other factors, high levels of receptor in the diabetic kidney may also be involved in the development of diabetic nephropathy. Increased IGF-II-receptor expression in the diabetic kidney may be important for the intracellular transport and packaging of lysosomal enzymes, although a role for this receptor in signal transduction cannot be excluded. Finally, the possible role of IGF-binding proteins requires further study.

  16. Task I: Dark Matter Search Experiments with Cryogenic Detectors: CDMS-I and CDMS-II Task II: Experimental Study of Neutrino Properties: EXO and KamLAND

    SciTech Connect

    Cabrera, Blas; Gratta, Giorgio

    2013-08-30

    Dark Matter Search - During the period of performance, our group continued the search for dark matter in the form of weakly interacting massive particles or WIMPs. As a key member of the CDMS (Cryogenic Dark Matter Search) collaboration, we completed the CDMS II experiment which led the field in sensitivity for more than five years. We fabricated all detectors, and participated in detector testing and verification. In addition, we participated in the construction and operation of the facility at the Soudan Underground Laboratory and played key roles in the data acquisition and analysis. Towards the end of the performance period, we began operating the SuperCDMS Soudan experiment, which consists of 15 advanced Ge (9 kg) detectors. The advanced detector design called iZIP grew out of our earlier DOE Particle Detector R&D program which demonstrated the rejection of surface electrons to levels where they are no longer the dominant source of background. Our group invented this advanced design and these larger detectors were fabricated on the Stanford campus in collaboration with the SLAC CDMS group and the Santa Clara University group. The sensitivity reach is expected to be up to 5 times better than CDMS II after two years of operation. We will check the new limits on WIMPs set by XENON100, and we expect improved sensitivity for light mass WIMPs beyond that of any other existing experiment. Our group includes the Spokesperson for SuperCDMS and continues to make important contributions to improvements in the detector technology which are enabling the very low trigger thresholds used to explore the low mass WIMP region. We are making detailed measurements of the charge transport and trapping within Ge crystals, measuring the diffusive trapping distance of the quasiparticle excitations within the Al phonon collector fins on the detector surface, and we are contributing to the development of much improved detector Monte Carlos which are essential to guide the detector

  17. A STUDY OF FUNDAMENTAL REACTION PATHWAYS FOR TRANSITION METAL ALKYL COMPLEXES. I. THE REACTION OF A NICKEL METHYL COMPLEX WITH ALKYNES. II. THE MECHANISM OF ALDEHYDE FORMATION IN THE REACTION OF A MOLYBDENUM HYDRIDE WITH MOLYBDENUM ALKYLS

    SciTech Connect

    Huggins, John Mitchell

    1980-06-01

    I. This study reports the rapid reaction under mild conditions of internal or terminal alkynes with methyl (acetyl~ acetonato) (triphenylphosphine) nickel (1) in either aromatic or ether solvents. In all cases vinylnickel products 2 are formed by insertion of the alkyne into the nickel=methyl bond. These complexes may be converted into a variety of organic products (e.g. alkenes, esters, vinyl halides) by treatment with appropriate reagents. Unsymmetrical alkynes give selectively the one regioisomer with the sterically largest substituent next to the nickel atom. In order to investigate the stereochemistry of the initial insertion, a x-ray diffraction study of the reaction of 1 with diphenylacetylene was carried out. This showed that the vinylnickel complex formed by overall trans insertion was the product of the reaction. Furthermore, subsequent slow isomerization of this complex, to a mixture of it and the corresponding cis isomer, demonstrated that this trans addition product is the kinetic product of the reaction. In studies with other alkynes, the product of trans addition was not always exclusively (or even predominantly) formed, but the ratio of the stereoisomers formed kinetically was substantially different from the thermodynamic ratio. Isotope labeling, added phosphine, and other experiments have allowed us to conclude that the mechanism of this reaction does involve initial cis addition. However, a coordinatively unsaturated vinylnickel complex is initially formed which can undergo rapid, phosphine-catalyzed cis-trans isomerization in competition with its conversion to the isolable phosphine-substituted kinetic reaction products. II. The reaction of CpMo(CO){sub 3}H (1a) with CpMo(CO){sub 3}R (2, R= CH{sub 3}, C{sub 2}H{sub 5}) at 50{degrees} C in THF gives the aldehyde RCHO and the dimers [CpMo(CO){sub 3}]{sub 2} (3a) and [CpMo(CO){sub 2}]{sub 2} (4a). Labeling one of the reactants with a methylcyclopentadienyl ligand it was possible to show that the

  18. Pyroprocessing of Oxidized Sodium-Bonded Fast Reactor Fuel -- an Experimental Study of Treatment Options for Degraded EBR-II Fuel

    SciTech Connect

    S. D. Herrmann; L. A. Wurth; N. J. Gese

    2013-09-01

    An experimental study was conducted to assess pyrochemical treatment options for degraded EBR-II fuel. As oxidized material, the degraded fuel would need to be converted back to metal to enable electrorefining within an existing electrometallurgical treatment process. A lithium-based electrolytic reduction process was studied to assess the efficacy of converting oxide materials to metal with a particular focus on the impact of zirconium oxide and sodium oxide on this process. Bench-scale electrolytic reduction experiments were performed in LiCl-Li2O at 650 °C with combinations of manganese oxide (used as a surrogate for uranium oxide), zirconium oxide, and sodium oxide. The experimental study illustrated how zirconium oxide and sodium oxide present different challenges to a lithium-based electrolytic reduction system for conversion of select metal oxides to metal.

  19. Crystal structures of tetra-methyl-ammonium (2,2'-bi-pyridine)-tetra-cyanidoferrate(III) trihydrate and poly[[(2,2'-bi-pyridine-κ(2) N,N')di-μ2-cyanido-dicyanido(μ-ethyl-enedi-amine)(ethyl-enedi-amine-κ(2) N,N')-cadmium(II)iron(II)] monohydrate].

    PubMed

    Chanthee, Songwuit; Punyain, Wikorn; Namuangrak, Supawadee; Chainok, Kittipong

    2016-05-01

    The crystal structures of the building block tetra-methyl-ammonium (2,2'-bi-pyridine-κ(2) N,N')tetra-cyanidoferrate(III) trihydrate, [N(CH3)4][Fe(CN)4(C10H8N2)]·3H2O, (I), and a new two-dimensional cyanide-bridged bimetallic coordination polymer, poly[[(2,2'-bi-pyridine-κ(2) N,N')di-μ2-cyanido-dicyanido(μ-ethyl-enedi-amine-κ(2) N:N')(ethyl-enedi-amine-κ(2) N,N')cadmium(II)iron(II)] monohydrate], [CdFe(CN)4(C10H8N2)(C2H8N2)2]·H2O, (II), are reported. In the crystal of (I), pairs of [Fe(2,2'-bipy)(CN)4](-) units (2,2'-bipy is 2,2'-bi-pyri-dine) are linked together through π-π stacking between the pyridyl rings of the 2,2'-bipy ligands to form a graphite-like structure parallel to the ab plane. The three independent water mol-ecules are hydrogen-bonded alternately with each other, forming a ladder chain structure with R 4 (4)(8) and R 6 (6)(12) graph-set ring motifs, while the disordered [N(CH3)4](+) cations lie above and below the water chains, and the packing is stabilized by weak C-H⋯O hydrogen bonds. The water chains are further linked with adjacent sheets into a three-dimensional network via O-H⋯O hydrogen bonds involving the lattice water mol-ecules and the N atoms of terminal cyanide groups of the [Fe(2,2'-bipy)(CN)4](-) building blocks, forming an R 4 (4)(12) ring motif. Compound (II) features a two-dimensional {[Fe(2,2'-bipy)(CN)4Cd(en)2]} n layer structure (en is ethyl-enedi-amine) extending parallel to (010) and constructed from {[Fe(2,2'-bipy)(CN)4Cd(en)]} n chains inter-linked by bridging en ligands at the Cd atoms. Classical O-H⋯N and N-H⋯O hydrogen bonds involving the lattice water mol-ecule and N atoms of terminal cyanide groups and the N-H groups of the en ligands are observed within the layers. The layers are further connected via π-π stacking inter-actions between adjacent pyridine rings of the 2,2'-bipy ligands, completing a three-dimensional supra-molecular structure. PMID:27308032

  20. Theoretical and experimental studies of two Co(II) and Ni(II) coordination complex with N,O donor 2-chloro-6-{[(4-hydroxy-3-methoxyphenyl)methylidene]amino}-4 nitrophenol ligand

    NASA Astrophysics Data System (ADS)

    Kusmariya, Brajendra S.; Tiwari, Sandeep; Tiwari, Anjali; Mishra, A. P.; Naikoo, Gowhar Ahmad; Pandit, Umar J.

    2016-07-01

    Here we report two mononuclear Co(II) and Ni(II) complexes of general formula [M(L)2(H2O)].2H2O; {M = CoII & NiII} derived from bidentate 2-chloro-6-{[(4-hydroxy-3-methoxyphenyl)methylidene]amino}-4 nitrophenol ligand (HL). These compounds were characterized by elemental analysis, spectral (FT-IR, electronic and 1H-NMR), molar conductance, thermal, PXRD, SEM and electrochemical studies. Distorted octahedral geometry was proposed around the metal center with ligand (HL). The PXRD and SEM analysis shows the crystalline nature of complexes. The broadening of diffraction peaks were explained in terms of domain size and the lattice strain according to Scherrer and Williamson-Hall method. TG of the synthesized complexes illustrates their general decomposition pattern and thermal stability. The kinetic and thermodynamic parameters viz. activation energy (E∗), pre-exponential factor (Z), entropy of activation (ΔS∗), enthalpy of activation (ΔH∗) and free energy of activation (ΔG∗) of degradation process were also evaluated using Coats-Redfern (C-R), Piloyan-Novikova (P-N) and Horowitz-Metzger (H-M) methods for both complexes assuming first order degradation. The optical band gap values of complexes were found to be in good agreement with calculated HOMO-LUMO energy gap (ΔE) and lie in semiconducting range. The cyclic voltammetric studies of synthesized compounds were carried out in order to examine their electrochemical behavior. In addition theoretical calculations by means of DFT at B3LYP level were incorporated to support the experimental findings.

  1. Hydrodynamic Impact of a System with a Single Elastic Mode II : Comparison of Experimental Force and Response with Theory

    NASA Technical Reports Server (NTRS)

    Miller, Robert W; Merten, Kenneth F

    1952-01-01

    Hydrodynamic impact tests were made on an elastic model approximating a two-mass spring system to determine experimentally the effects of structural flexibility on the hydrodynamic loads encountered during seaplane landing impacts and to correlate the results with theory. A flexible seaplane was represented by a two-mass spring system consisting of a rigid prismatic float connected to a rigid upper mass by an elastic structure. The model had a ratio of sprung mass to hull mass of 0.6 and a natural frequency of 3.0 cycles per second. The tests were conducted in smooth water at fixed trims and included both high and low flight-path angles and a range of velocity. Theoretical and experimental comparisons indicated that the theoretical results agreed well with the experimental results.

  2. Experimental determination of band overlap in type II InAs/GaSb superlattice based on temperature dependent photoluminescence signal

    NASA Astrophysics Data System (ADS)

    Huang, Jianliang; Ma, Wenquan; Zhang, Yanhua; Cao, Yulian; Liu, Ke; Huang, Wenjun; Luo, Shuai; Ji, Haiming; Yang, Tao

    2015-12-01

    We have determined the band overlap in type II InAs/GaSb superlattice (SL) structure based on the temperature dependent photoluminescence (PL) results of a short wavelength SL sample. The band overlap value is treated as a temperature variable and is simulated by fitting the PL peak position using the 8K·P method. It is found that the band overlap monotonically decreases from 0.325 to 0.225 eV when temperature is increased from 12 to 90 K. The calculated e1-hh1 transition using the obtained band overlap data shows an agreement with the PL results of another SL sample.

  3. A Theoretical-Experimental Study on the Structure and Activity of Certain Quinolones and the Interaction of Their Cu(II)-Complexes on a DNA Model

    PubMed Central

    Robles, J.; Martín-Polo, J.; Álvarez-Valtierra, L.; Hinojosa, L.

    2000-01-01

    Theoretical electronic Structure methods have been employed to study the structure and activity of certain (free) quinolones and the interaction of their Cu(II)-complexes on a DNA model (Rhodamine 6G (rhod)). As a manner of assessing the generated geometries, the nalidixic acid geometrical parameters obtained were tested against the crystallographic ones and it was found that the average error in the calculated geometries is small. The present study allows us to (1) Rationalize the observed differences in antibiotic activities through their electronic hardnesses. (2) Suggest a plausible mechanism of action for these drugs through formation of a reactive intermediate (or carrier) which would consist of a quinolone anion coordinated to an adequate metal center (Cu(II) in this study). (3) We find that, through this model of DNA (modeled with rhod) the interaction seems to be mediated by an effective π-π stacking. (4) Finally, an in vitro experiment was designed so that the intercalation process in DNA could be experimentally modeled as well. The quenching of the rhod fluorescence is proportional to the strength of the Cu(II)-complex-rhod interaction and therefore provides a quantitative measurement of the “intercalating” capacity of the quinolones and their copper complexes. These results agree well with the theoretical total adduct formation energies. PMID:18475962

  4. Biotic and abiotic mercury methylation and demethylation in sediments

    SciTech Connect

    Zhang, L.; Planas, D. )

    1994-05-01

    Inorganic mercury (Hg(II)) methylation and methylmercury (MeHg) demethylation may occur in the water column, sediment-water interface and subsurficial sediment of aquatic ecosystems. These transformations involve mainly microbial mechanisms, although abiotic methylation may play a more important role in the water compartment. The relative importance of biotic versus abiotic mechanisms of methylation has not been determined however, and abiotic demethylation remains unknown. Little quantitative information is available on the role of bacterial activity in mercury transformations. It has been reported that at least 16 genera of aerobic and anaerobic microorganisms are able to methylate HG(II), and that a greater number are able to demethylate MeHg. Nevertheless, not all populations of these species are capable of methyl- and demethyl-transformations. The actual concentration of MeHg in the aquatic environment is regulated by the relative production and decomposition rates. This, in turn, depends on the availability of Hg(II), MeHg, and bacteria as well as on the physico-chemical properties of the sample. The objective of this study was to compare mercury methylation and demethylation rates in sediment samples with and without active bacterial populations. We therefore performed experiments to follow bacterial evolution during the course of Hg(II) methylation and MeHg demethylation in sediment slurries containing both sterile and non-sterile sediments.

  5. An experimental study of CTOD for Mode I/Mode II stable crack growth in thin 2024-T3 aluminum specimens

    SciTech Connect

    Amstutz, B.E.; Sutton, M.A.; Dawicke, D.S.; Newman, J.C.

    1995-12-31

    An experimental study of crack tip opening displacement (CTOD) for Mode I/Mode II stable crack growth in thin sheet 2024-T3 aluminum has been conducted. To perform the experiments, an Arcan specimen and fixture was modified so that (1) slippage in the grips was eliminated, (2) large rotations of the fixture components were achievable and (3) bending stresses were minimized. Defining {Theta} to be the angle between the Mode I loading direction (perpendicular to the crack line) and the direction of applied loading, experimental results indicate that (a) for large amounts of crack extension, a {ge} 10mm, the value of CTOD at 1 mm behind the crack tip appears to approach a constant value of 0.1 mm for all modes of loading, (b) the direction of crack extension varied with applied mixed mode loading, (c) Mode I crack extension is predominant for 0{degree} {le} {Theta} {le} 60{degree}, (d) Mode II crack extension is predominant for 75{degree} {le} {Theta} {le} 90{degree} and (e) a transition zone exists for angles {Theta} near 75{degree}.

  6. Experimental validation of type-II tip-tilt control in a woofer-tweeter adaptive optics system

    NASA Astrophysics Data System (ADS)

    Jackson, Kate; Conan, Rodolphe; Veran, Jean-Pierre

    2010-07-01

    Woofer-Tweeter Adaptive Optics (AO) systems use two Deformable Mirrors (DM) with a single wavefront sensor (WFS) to correct for optical aberrations. The splitting of the DM commands derived from the WFS measurements must accommodate both the spatial and temporal bandwidth of the DMs. This paper reports on a woofer-tweeter experiment developed at the AO laboratory of the University of Victoria. This experiment uses a tip-tilt mirror as a woofer and a 9×9 CILAS PZT DM as a tweeter. The response of the woofer is slowed down in order to reproduce the behavior of the tip-tilt platform supporting the DM of the TMT/ NFIRAOS system. For this experiment, only the tip-tilt mode is considered, especially the off-loading of the low temporal frequencies of the tip-tilt mode from the DM to the slow tip-tilt mount is investigated. The closed-loop controller is a type II controller with a cascade of two integrators and a lead filter. The performance of this Woofer-Tweeter scheme as measured in the experiment is presented, and compared with the performance predicted by a hybrid Simulink model. The increased rejection achieved by the type II controller compared to a classical controller is quantified, as well as the increase in the associated noise propagation.

  7. Experimental observation of supramolecular carbonyl-π/π-π/π-carbonyl assemblies of Cu II complex of iminodiacetate and dipyridylamine

    NASA Astrophysics Data System (ADS)

    Kumar Seth, Saikat; Dey, Biswajit; Kar, Tanusree; Mukhopadhyay, Subrata

    2010-06-01

    A mononuclear Cu II complex [Cu(IDA)(2,2'-dypam)(H 2O)]·H 2O ( 1) where H 2IDA and 2,2'-dypam are iminodiacetic acid and 2,2´-dipyridylamine, respectively, has been synthesized and characterized by X-ray single crystal structure analysis. The Cu(II) atom exhibits an unsymmetrical elongated octahedral coordination type 4 + 1 + 1. X-ray crystallography reveals that complex ( 1) has an unprecedented fac-O 2 + N(apical) IDA conformation, in the trans-site of Cu-N (IDA-like) bond, in contrast with structural co-relations for complexes with Cu/(IDA or IDA-like)/N-heterocyclic donor ratio 1/1/2 and closely related compounds fac-NO + O(apical) IDA-like conformation and one N-heterocyclic donor in the trans-site to the Cu-N (IDA-like) bond. These findings are attributed to the influence of π-π stacking, C-H⋯π interactions in the molecular recognition process. Moreover, the aromatic moieties of 2,2'-dypam are engaged in carbonyl⋯π interaction with the non-coordinated carbonyl groups of IDA ligand and giving rise to a remarkable supramolecular carbonyl-π/π-π/π-carbonyl interactions.

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

    NASA Astrophysics Data System (ADS)

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

    2015-08-01

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

  9. Electronic structure and vibrational spectra of cis-diammine(orotato)platinum(II), a potential cisplatin analogue: DFT and experimental study

    NASA Astrophysics Data System (ADS)

    Wysokiński, Rafał; Hernik, Katarzyna; Szostak, Roman; Michalska, Danuta

    2007-03-01

    Orotic acid (vitamin B 13) is a key intermediate in biosynthesis of the pyrimidine nucleotides in living organisms, moreover, it may serve as the biological carrier for some metal ions. cis-Diammine(orotato)platinum(II), cis-[Pt(C 5H 2N 2O 4)(NH 3) 2] can be considered as a new potential cisplatin analogue. The FT-Raman and FT-IR spectra of the title complex are reported, for the first time. The molecular structure, vibrational frequencies, and the theoretical infrared and Raman intensities have been calculated by the density functional mPW1PW91 method. The detailed vibrational assignment has been made on the basis of the calculated potential energy distribution. The theoretically predicted IR and Raman spectra show very good agreement with experiment. Natural bond orbital (NBO) analyses were performed for cisplatin, carboplatin and the title complex. The results provided new data on the nature of platinum-ligand bonding in these compounds. Strong intramolecular hydrogen bond between the orotate ligand and the coordinated ammonia group stabilizes the structure of the platinum(II) complex. Thus, it is suggested that the orotate ligand in the title complex is more inert to the substitution reactions than the chloride ligands in cisplatin.

  10. Intensive Language Instruction, Experimental Development and Guidance Report (Hartford SADC Project II B) Evaluation 1965-1966.

    ERIC Educational Resources Information Center

    Hartford City Board of Education, CT. Research and Publication Dept.

    This document describes two third- and ninth-grade experimental centers which were established to develop language competence and academic motivation in disadvantaged students in Hartford. Evaluation of the ninth-grade "Higher Horizons 100" center is presented. Composed of six staff members, the center provided intensive small-group instruction to…

  11. Experimental type II diabetes and related models of impaired glucose metabolism differentially regulate glucose transporters at the proximal tubule brush border membrane.

    PubMed

    Chichger, Havovi; Cleasby, Mark E; Srai, Surjit K; Unwin, Robert J; Debnam, Edward S; Marks, Joanne

    2016-06-01

    What is the central question of this study? Although SGLT2 inhibitors represent a promising treatment for patients suffering from diabetic nephropathy, the influence of metabolic disruption on the expression and function of glucose transporters is largely unknown. What is the main finding and its importance? In vivo models of metabolic disruption (Goto-Kakizaki type II diabetic rat and junk-food diet) demonstrate increased expression of SGLT1, SGLT2 and GLUT2 in the proximal tubule brush border. In the type II diabetic model, this is accompanied by increased SGLT- and GLUT-mediated glucose uptake. A fasted model of metabolic disruption (high-fat diet) demonstrated increased GLUT2 expression only. The differential alterations of glucose transporters in response to varying metabolic stress offer insight into the therapeutic value of inhibitors. SGLT2 inhibitors are now in clinical use to reduce hyperglycaemia in type II diabetes. However, renal glucose reabsorption across the brush border membrane (BBM) is not completely understood in diabetes. Increased consumption of a Western diet is strongly linked to type II diabetes. This study aimed to investigate the adaptations that occur in renal glucose transporters in response to experimental models of diet-induced insulin resistance. The study used Goto-Kakizaki type II diabetic rats and normal rats rendered insulin resistant using junk-food or high-fat diets. Levels of protein kinase C-βI (PKC-βI), GLUT2, SGLT1 and SGLT2 were determined by Western blotting of purified renal BBM. GLUT- and SGLT-mediated d-[(3) H]glucose uptake by BBM vesicles was measured in the presence and absence of the SGLT inhibitor phlorizin. GLUT- and SGLT-mediated glucose transport was elevated in type II diabetic rats, accompanied by increased expression of GLUT2, its upstream regulator PKC-βI and SGLT1 protein. Junk-food and high-fat diet feeding also caused higher membrane expression of GLUT2 and its upstream regulator PKC

  12. Lesions and distribution of viral antigen following an experimental infection of young seronegative calves with virulent bovine virus diarrhea virus-type II.

    PubMed Central

    Ellis, J A; West, K H; Cortese, V S; Myers, S L; Carman, S; Martin, K M; Haines, D M

    1998-01-01

    During the past several years, acute infections with bovine viral diarrhea virus (BVDV) have been causally linked to hemorrhagic and acute mucosal disease-like syndromes with high mortality. The majority of BVDVs isolated in such cases have been classified as type II on the basis of genetic and antigenic characteristics. It was our objective to examine clinical disease, lesions and potential sites of viral replication, following experimental BVDV type II infection in young calves. On approximately day 35 after birth, calves that had received BVDV-antibody-negative colostrum were infected by intranasal inoculation of 5 x 10(5) TCID50 of BVDV type II isolate 24,515 in 5 mL of tissue culture fluid (2.5 mL/nostril). Calves were monitored twice daily for signs of clinical disease. Approximately 48-72 h after infection, all calves developed transient pyrexia (39.4-40.5 degrees C) and leukopenia. Beginning on approximately day 7 after infection, all calves developed watery diarrhea, pyrexia (40.5-41.6 degrees C), marked leukopenia (> or = 75% drop from preinoculation values), variable thrombocytopenia, and moderate to severe depression. Calves were euthanized on days 10, 11, or 12 after infection due to severe disease. Gross and histological lesions consisted of multifocal bronchointerstitial pneumonia (involving 10%-25% of affected lungs), bone marrow hypoplasia and necrosis, and minimal erosive lesions in the alimentary tract. Immunohistochemical staining for BVDV revealed widespread viral antigen usually within epithelial cells, smooth muscle cells and mononuclear phagocytes in multiple organs, including lung, Peyer's patches, gastric mucosa, thymus, adrenal gland, spleen, lymph nodes, bone marrow, and skin. This BVDV type II isolate caused rapidly progressive, severe multisystemic disease in seronegative calves that was associated with widespread distribution of viral antigen and few gross or histological inflammatory lesions. Images Figure 1. Figure 2. Figure 3

  13. Quantum chemical calculations and experimental investigations on 2-aminobenzoic acid-cyclodiphosph(V)azane derivative and its homo-binuclear Cu(II) complex

    NASA Astrophysics Data System (ADS)

    El-Gogary, Tarek M.; Alaghaz, Abdel-Nasser M. A.; Ammar, Reda A. A.

    2012-03-01

    A novel 2-aminobenzoic acid-cyclodiphosph(V)azane ligand H4L and its homo-binuclear Cu(II) complex of the type [Cu2L(H2O)2].2.5 H2O in which L is 1,3-di(-o-pyridyl)-2,4-(dioxo)-2',4'-bis-(2-iminobenzoic acid) cyclodiphosph(V)azane, were synthesized and characterized by different physical techniques. Infrared spectra of the complex indicate deprotonation and coordination of the imine NH and carboxyl COOH groups. It also confirms that nitrogen atom of the pyridine ring contribute to the complexation. Electronic spectra and magnetic susceptibility measurements reveal square-planar geometry for the Cu(II) complex. The elemental analyses and thermogravimetric results have justified the [Cu2L(H2O)2]·2.5H2O composition of the complex. Quantum chemical calculations were utilized to explore the electronic structure and stability of the H4L as well as the binuclear Cu(II) complex. Computational studies have been carried out at the DFT-B3LYP/6-31G(d) level of theory on the structural and spectroscopic properties of H4L and its binuclear Cu(II) complex. Different tautomers and geometrical isomers of the ligand were optimized at the ab initio DFT level. Simulated IR frequencies were scaled and compared with that experimentally measured. TD-DFT method was used to compute the UV-VIS spectra which show good agreement with measured electronic spectra.

  14. ARSENIC (+3 OXIDATION STATE) METHYLTRANSFERASE AND THE INORGANIC ARSENIC METHYLATION PHENOTYPE

    EPA Science Inventory

    Inorganic arsenic is enzymatically methylated; hence, its ingestion results in exposure to the parent compound and various methylated arsenicals. Both experimental and epidemiological evidence suggest that some of the adverse health effects associated with chronic exposure to in...

  15. Impact of Benznidazole on Infection Course in Mice Experimentally Infected with Trypanosoma cruzi I, II, and IV

    PubMed Central

    Gruendling, Ana Paula; Massago, Miyoko; Teston, Ana Paula M.; Monteiro, Wuelton M.; Kaneshima, Edilson N.; Araújo, Silvana M.; Gomes, Mônica L.; Barbosa, Maria das Graças V.; Toledo, Max Jean O.

    2015-01-01

    American trypanosomiasis is an emerging zoonosis in the Brazilian Amazon. Studies on benznidazole (BZ) chemotherapy with Trypanosoma cruzi from this region have great relevance, given the different discrete typing units (DTUs) that infect humans in the Amazon and other regions of Brazil. We performed a parasitological, histopathological, and molecular analysis of mice inoculated with strains of T. cruzi I, II, and IV that were BZ-treated during the acute phase of infection. Groups of Swiss mice were inoculated; 13 received oral BZ, whereas the other 13 comprised the untreated controls. Unlike parasitemia, the infectivity and mortality did not vary among the DTUs. Trypanosoma cruzi DNA was detected in all tissues analyzed and the proportion of organs parasitized varied with the parasite DTU. The BZ treatment reduced the most parasitological parameters, tissue parasitism and the inflammatory processes at all infection stages and for all DTUs. However, the number of significant reductions varied according to the DTU and infection phase. PMID:25940197

  16. Syphilis and human experimentation from World War II to the present: a historical perspective and reflections on ethics.

    PubMed

    Cuerda-Galindo, E; Sierra-Valenti, X; González-López, E; López-Muñoz, F

    2014-11-01

    Even after the Nuremberg code was published, research on syphilis often continued to fall far short of ethical standards. We review post-World War II research on this disease, focusing on the work carried out in Guatemala and Tuskegee. Over a thousand adults were deliberately inoculated with infectious material for syphilis, chancroid, and gonorrhea between 1946 and 1948 in Guatemala, and thousands of serologies were performed in individuals belonging to indigenous populations or sheltered in orphanages. The Tuskegee syphilis study, conducted by the US Public Health Service, took place between 1932 and 1972 with the aim of following the natural history of the disease when left untreated. The subjects belonged to a rural black population and the study was not halted when effective treatment for syphilis became available in 1945. PMID:24461955

  17. Synthesis, structure and spectral properties of O,N,N coordinating ligands and their neutral Zn(ii) complexes: a combined experimental and theoretical study.

    PubMed

    Hens, Amar; Mondal, Pallab; Rajak, Kajal Krishna

    2013-10-01

    Mononuclear Zn(ii) complexes with the general formula [Zn(L)2] have been synthesized in good yields by reacting Zn(OAc)2 with HL in a ratio of 1 : 2 in methanol solvent. Here L is the deprotonated form of 6-[(quinolin-8-ylamino)methylene]cyclohexa-2,4-dienone (HL(1)), 4-chloro-6-[(quinolin-8-ylamino)methylene]cyclohexa-2,4-dienone (HL(2)), 4-methyl-6-[(quinolin-8-ylamino)methylene]cyclohexa-2,4-dienone (HL(3)), 2,4-dimethyl-6-[(quinolin-8-ylamino) methylene]cyclohexa-2,4-dienone (HL(4)), 2-methoxy-6-[(quinolin-8-ylamino) methylene]cyclohexa-2,4-dienone (HL(5)). The electronic structures and photophysical properties of the ligands were calculated by DFT and TDDFT methods. The X-ray structure of one complex is reported. The ligands have a strong binding ability [(0.75-15.37) × 10(4)] and ratiometric response to Zn(2+) ions. With the addition of Zn(2+) ions to the ligands in THF solution a sharp color change is observed visually, and as well a significant enhancement of the fluorescence intensity and the quantum yield for this series occurs. The introduction of other metal ions having biological and environmental effects results in either unaltered or quenched emission intensity. However we observed the sensing property of the ligands strongly depends on the substituent at the ortho position of the phenol group. DFT calculation reveals that the ICT process take place from the salicylaldehyde (donor moiety) to quinoline (acceptor moiety) which is responsible for the enhancement of the fluorescence intensity of ligands after complexation. PMID:23995072

  18. Phase Equilibria in Ferrous Calcium Silicate Slags: Part II. Evaluation of Experimental Data and Computer Thermodynamic Models

    NASA Astrophysics Data System (ADS)

    Nikolic, Stanko; Henao, Hector; Hayes, Peter C.; Jak, Evgueni

    2008-04-01

    Ferrous calcium silicate slags (described by the FeO-Fe2O3-CaO-SiO2 system) are the basis for a number of slag systems used in nonferrous smelting. Characterization of this slag system is necessary to improve the design and optimization parameters of new processes, including fluxing and operating temperatures. Particularly of interest are the phase relations at intermediate oxygen partial pressures relevant to processes such as copper converting. Experimental data on the phase equilibria of these slags at controlled oxygen partial pressures in the temperature range between 1200 °C and 1350 °C are discussed, differences between various data sources are analyzed, and discrepancies are resolved. An evaluation of two thermodynamic computer models is undertaken to verify the computer-aided predictions using the experimental data. New experimental data for this system are reported for the temperature condition of 1300 °C, defined using the equilibration/rapid-quenching/electron probe microanalysis (EPMA) with wavelength dispersive detectors technique. This new information, combined with results from the previous study, has enabled the equilibrium liquidus compositions to be defined over a wide range of temperatures and oxygen partial pressures.

  19. Rotational spectrum, conformation and dipole moment of 4-methyl-1,3-dioxane

    NASA Astrophysics Data System (ADS)

    Shapkin, A. A.; Galeev, R. V.; Gunderova, L. N.; Fayzullin, M. G.; Mamleev, A. H.

    2006-12-01

    The rotational spectrum of 4-methyl-1,3-dioxane, C 5H 100 II, has been recorded from 16.0 to 40.0 GHz. The a-, b- and C- type transitions with J<=57 have been observed and assigned for the normal species in the ground vibrational state. The rotational constants and the quartic centrifugal distortion constants were determined to be A = 4802.335(2) MHz, B = 2376.163(1) MHz, C = 1738.852(1) MHz and Δ J = 0.1496(6) kHz, Δ JK = 0.157(5) kHz, Δ K = 0.76(3) kHz, δJ = 0.0423(1) kHz, δK 0.260(3) kHz. Stark effect measurements were used to determine the projections of the dipole moment on the principal inertial axes (in Debye units): μ a = 0.73(1), μ b = 1.32(1), c = 1.36(1) and μ tot = 2.03(2). Comparison of the experimental rotational constants and dipole moment components with results of ab initio calculations (B3PW91/aug-cc-pVDZ) shown that 4-methyl-l,3-dioxane exist in chair form with equatorial orientation of methyl group.

  20. Multiple sites of methylation in the methyl accepting chemotaxis proteins of Escherichia coli

    SciTech Connect

    Chelsky, D.; Dahlquist, F.W.

    1981-01-01

    The methyl-accepting chemotaxis proteins (MCP) of E coli show at least five bands when subjected to SDS-gel electrophoresis. The intensity of the individual bands varies depending on the environment of the cells before solubilization. The faster migrating bands are enhanced following attractant stimulation, whereas the slower migrating bands are enhanced following attractant dilution or repellent increase. The time scale of these intensity changes is similar to that for adaptation of the behavioral response in these cells suggesting that methylation of the MCP is involved in producing these bands. Peptide mapping experiments show three methylated peptides in both MCP I and MCP II. These results suggest multiple sites of methylation, which are responsible, at least in part, for the observed multiple bands of the MCPs.

  1. Cobalt(II)-Based Single-Ion Magnets with Distorted Pseudotetrahedral [N2O2] Coordination: Experimental and Theoretical Investigations.

    PubMed

    Ziegenbalg, Sven; Hornig, David; Görls, Helmar; Plass, Winfried

    2016-04-18

    The synthesis and magnetic properties of cobalt(II) complexes with sterically demanding Schiff-base ligands are reported. The compounds [Co(L(Br))2] (1) and [Co(L(Ph))2]·CH2Cl2 (2·CH2Cl2) are obtained by the reaction of cobalt(II) acetate with the ligands HL(Br) and HL(Ph) in a dichloromethane/methanol mixture. 1 and 2 crystallize in the space groups P21212 and P1̅, respectively. X-ray diffraction studies revealed mononuclear constitution of both complexes. For 1, relatively short intermolecular Co-Co distances of 569 pm are observed. In compound 2, a hydrogen-bonded dichloromethane molecule is present, leading to a solvent aggregate with remarkable thermal stability for which desolvation is taking place between 150 and 210 °C. Magnetic measurements were performed to determine the zero-field-splitting (ZFS) parameter D for both complexes. Frequency-dependent susceptibility measurements revealed slow magnetic relaxation behavior with spin-reversal barriers of 36 cm(-1) for 1 and 43 cm(-1) for 2 at an applied external field of 400 Oe. This observation is related to an increasing distortion of the pseudotetrahedral coordination geometry for complex 2. These distortions can be decomposed in two major contributions. One is the elongation effect described by the parameter ϵT, which is the ratio of the averaged obtuse and acute bond angles. The other effect is related to a twisting distortion of the chelate coordination planes at the cobalt center. A comparison with literature examples reveals that the elongation effect seems to govern the overall magnetic behavior in pseudotetrahedral complexes with two bidentate chelate ligands. Ab initio calculations for complexes 1 and 2 using the CASPT2 method show strong splitting of the excited (4)T2 term, which explains the observed strong ZFS. Spin-orbit calculations with the RASSI-SO method confirm the single-molecule-magnet behavior because only small transversal elements are found for the lowest Kramers doublet for both

  2. [The experimental examination of the effect on the uterine blood flow of angiotensin II during pregnancy (author's transl)].

    PubMed

    Schmidt, A W

    1976-10-15

    In experiments with animals it was investigated the endurance of the myometrial and the blood flow of the renal cortex during endogenous pressure substances. At the same time it was tested, if treatment with sexual hormones or a pregnancy had the tested principles and changes through pressure substances, and that the changes were significant. The investigations were conducted on three groups of female rabbits. The blood changes in myometrial and in the uterine were measured and continually registered with the special heated thermistor, from the principle of the thermoclearance. The success of the blood pressure was intraarterial measured with an electric mechanism. Precisely the same doses (in relativity of the animals weight) of pressure substances were applied with an infusions pump intravenously. And pressure substances Angiotensin II, Norepinephrine and Epinephrine, and their actions on the blood pressure and blood flow through the myometrium and through the renal cortex were examined. Altogether 131 values were registered. The results of the study that were statistically secure were as follows: a) The uterine blood flow pro tissue volume unit stays constant also by pregnancy or pseudopregnancy. b) The blood flow of the kidney is perhaps twice as high as the myometrial. c) The myometrial blood flow is with the arterial systolic blood pressure tightly correlated. Blood pressure increases through Angiotensin-infusion and also recovery of the uterine blood flow. d) An autoregulation of the uterine blood flow is not observed. e) The decrease of the renal blood flow after the giving of pressure substances was not modified through pregnancy. f) In quality the behaviour of the organ blood flow is the same after applied infusion of the pressure substances. Quantity differences exist however between Angiotensin II, Norepinephrine and Epinephrine. The method of measuring the blood flow through the uterus and in the kidney was placed in one view there. The finding of

  3. Experimental studies of hydrogen on boron nitride: II. NMR studies of orientational ordering of H{sub 2}

    SciTech Connect

    Evans, M.D.; Sullivan, N.S.

    1995-09-01

    The authors report the results of NMR studies of thin films of hydrogen adsorbed on hexagonal boron nitride. Orientational ordering is observed below 1 K but the ordering is not complete, and a clear two-component ordering is observed. Molecules are either (i) almost completely ordered with local order parameters {sigma}={l_angle}1{minus}3/2Jz{sup 2}{r_angle} clustered close to a maximum value of {sigma}{congruent}0.94 (comparable to the values for long range ordering in bulk samples at high ortho concentrations), and (ii) a large fraction of the molecules that remain nearly disordered with {sigma}{<=}0.25. The degree of orientational ordering depends on the number of hydrogen layers and on the ortho-hydrogen concentration, and these studies indicate that ordering occurs principally in the first four layers closest to the substrate, with weaker orientational ordering in the outer layers near the free surface even at temperatures as low as 210 mK.

  4. Experimental and analytical study of loss-of-flow transients in EBR-II occurring at decay power levels

    SciTech Connect

    Chang, L.K.; Mohr, D.; Feldman, E.E.; Betten, P.R.; Planchon, H.P.

    1985-01-01

    A series of eight loss-of-flow (LOF) tests have been conducted in EBR-II to study the transition between forced and natural convective flows following a variety of loss-of-primary-pumping power conditions from decay heat levels. Comparisons of measurements and pretest/posttest predictions were made on a selected test. Good agreements between measurements and predictions was found prior to and just after the flow reaching its minimum, but the agreement is not as good after that point. The temperatures are consistent with the flow response and the assumed decay power. The measured results indicate that the flows of driver and the instrumented subassemblies are too much in the analytical model in the natural convective region. Although a parametric study on secondary flow, turbulent-laminar flow transition, heat transfer ability of the intermediate heat exchange at low flow and flow mixing in the primary tank has been performed to determine their effects on the flow, the cause of the discrepancy at very low flow level is still unknown.

  5. Study on a new type of sealing - regeneration-labyrinth sealing for displacer in cryocoolers: Part II - Experimental study

    NASA Astrophysics Data System (ADS)

    Liu, L. Q.; Zhang, L.

    2000-02-01

    The regeneration-labyrinth sealing has been employed in the G-M refrigerator first with the cold regenerator outside the displacer. Sealing effects of the new structure, the sealing rings with opening, and the ones without opening have been compared. The performance of the cryocooler with these three sealing structures has also been contrasted. At the same time, influences of the displacer-cylinder gap and regenerative capacity of displacers on the performance of the cryocooler have been researched experimentally. The regeneration-labyrinth sealing is used in the G-M refrigerator with the cold regenerator inside the displacer (general structure) consequently. Influences of some parameters of the new type of sealing on the performance of the refrigerator were studied experimentally. The results of experiments illustrate that the cooling temperature of the second stage of the G-M refrigerator reaches 3.70 K, which marks the success of applying the regeneration-labyrinth sealing to the G-M refrigerator.

  6. Some new nano-sized Cr(III), Fe(II), Co(II), and Ni(II) complexes incorporating 2-((E)-(pyridine-2-ylimino)methyl)napthalen-1-ol ligand: Structural characterization, electrochemical, antioxidant, antimicrobial, antiviral assessment and DNA interaction.

    PubMed

    Abdel-Rahman, Laila H; Abu-Dief, Ahmed M; Newair, Emad F; Hamdan, Samar Kamel

    2016-07-01

    To estimate the biological preference of synthetic small drugs towards DNA target, new metal based chemotherapeutic agents of nano-sized Cr(III), Fe(II), Co(II) and Ni(II) Schiff base complexes having N,N,O donor system were synthesized and thoroughly characterized by physic-chemical techniques. The redox behavior of the Cr(III), Fe(II) and Co(II) complex was investigated by electrochemical method using cyclic voltammetry. IR results proven that the tridentate binding of Schiff base ligand with metal center during complexation reflects the proposed structure. Magnetic and spectroscopic data give support to octahedral geometry for Cr(III) and Fe(II) complexes and tetrahedral geometry for Ni(II) and Co(II) complexes. The activation thermodynamic parameters, such as, E(⁎), ΔH(⁎), ΔS(⁎) and ΔG(⁎) are calculated using Coats-Redfern method by analyzing the TGA data. The particle size of the investigated metal complexes was estimated by TEM. In addition to, the interaction of the nanosized complexes with CT-DNA was estimated by electronic absorption, viscosity and gel electrophoresis. These techniques revealed that the complexes could bind to CT-DNA through intercalation mode. Moreover, the in vitro cytotoxic and antiviral activities of the nanosized complexes were checked against Herpes Simplex virus and Tobacco Mosaic viruses. Moreover, investigation of antioxidant activities of the new nanosized compounds was done by ABTS assay. Among the compounds tested, Fe(II) complex showed the strongest potent radical scavenging activity with percent of 58.60%. Furthermore, the antimicrobial bustle of the prepared compounds was screened against different types of bacteria and fungi and the results show that all metal complexes have superior activity than its free ligand. PMID:27088506

  7. [Accidental methyl alcohol poisoning].

    PubMed

    Xiao, J H

    1990-05-01

    An accidental poisoning due to drinking methyl alcohol in Chaoyang county is reported, analysing the accident. The poison came from the "retail white spirit" which was contaminated with methyl alcohol. Twenty-nine persons drank the wine, fourteen of them died, two of them became blind. After drinking this "retail white spirit" the drinkers showed symptoms of vertigo, headache, weakness, vomiting, night sweat, dyspnea and blurring of vision etc. within 6-120 hours. On examining the remaining spirit, we found the content of methyl alcohol to be between 16.6 and 40.69 g/100 ml. Some of the patients' urine and blood also contained methyl alcohol. We reckoned that each one of the twenty patients had taken more than 27 g of methyl alcohol and each of the ten dead drank more than 40 ml of the alcohol. PMID:2253526

  8. Protective role of the neuropeptide Urocortin II against experimental sepsis and leishmaniasis by direct killing of pathogens

    PubMed Central

    Campos-Salinas, Jenny; Caro, Marta; Cavazzuti, Antonio; Forte-Lago, Irene; Beverley, Stephen M.; O'Valle, Francisco; Gonzalez-Rey, Elena

    2013-01-01

    We currently face an alarming resurgence in infectious diseases characterized by antimicrobial resistance and therapeutic failure. This has generated the urgent need of developing new therapeutic approaches that include agents with non-traditional modes of action. A recent interest focused on approaches based on our natural immune defenses, especially on peptides which combine innate antimicrobial activity against diverse pathogens and immunoregulatory functions. Here, we describe for the first time the antimicrobial activity of the neuropeptide urocortin II (UCNII) against a panel of Gram-positive and Gram-negative bacteria and tropical parasites of the genus Leishmania. Importantly, this cytotoxicity was selective for pathogens, because UCNII did not affect mammalian cell viability. Structurally, UCNII has a cationic and amphipathic design that resembles antimicrobial peptides. Using mutants and UCNII-fragments, we determined the structural requirements for the interaction between the peptide and the surface of pathogen. Following its binding to pathogen, UCNII caused cell death through different membrane disrupting mechanisms that involve aggregation and membrane depolarization in bacteria and pore formation in Leishmania. Noteworthy, UCNII killed the infective form of L. major even inside the infected macrophages. Consequently, UCNII prevented mortality caused by polymicrobial sepsis and ameliorated pathological signs of cutaneous leishmaniasis. Besides its presence in body physical and mucosal barriers, we found that innate immune cells produce UCNII in response to infections. Therefore, UCNII could be considered as an ancient highly-conserved host peptide involved in the natural antimicrobial defense and emerge as an attractive alternative to current treatments for microbial disorders with associated drug-resistances. PMID:24249730

  9. Evolution of heavy metal tolerance in bryophytes II. An ecological and experimental investigation of the copper moss, Scopelophila cataractae (Pottiaceae)

    SciTech Connect

    Shaw, J. )

    1987-06-01

    About six bryophyte species (including both mosses and liverworts) are generally thought to be restricted to copper-enriched substrates and are consequently known as copper mosses. One of these, Scopelophila cataractae (Pottiaceae), is known from several sites in southern Arizona and occurs at six localities in the Eastern US. Chemical analyses of substrates from the eastern US localities showed that all but one population grew on copper-enriched soil. The one substrate sample low in copper was very high in iron. Plants from five of the six eastern US localities for S. cataractae were grown experimentally on four soil types ranging from highly to not contaminated, and all grew best on the soil contaminated with copper, lead, and zinc. There was no significant variation in growth between populations on the four soil treatments. This lack of population differentiation is in contrast to flowering plants and may be related to the absence of sexual reproduction in S. cataractae in North America.

  10. Long-pulse laser-induced damage in an optical anti-reflective film: II. Experimental research

    NASA Astrophysics Data System (ADS)

    Li, Changli; Ma, Yao; Wang, Di; Wang, Zhiyang; Zhang, Xihe; Liu, Haiming

    2014-12-01

    In order to verify the result of theoretical analysis about long-pulse flat-topped multi-Gaussian laser-induced damage in an optical anti-reflection film with HfO2/SiO2 composite film coating on a BK7 substrate (BK7:HfO2/SiO2), an experimental system was built, which carried out the experiment and analysis, focusing on the pulse-length 1.0 ms, flat-topped laser-induced damage. The result shows that the thermal effect is the main reason for damage under the long-pulse flat-topped laser. Moreover, the stripping and shedding occur because of the heating stress of the film happening at an early stage of the laser irradiation. However, the crack happens at laser irradiation termination. The correctness of the theoretical analysis results is verified.

  11. Background considerations for the 2H(7Be,3H)6Be experimental data II: Three-body continuum

    NASA Astrophysics Data System (ADS)

    Chae, K. Y.; Guimarães, V.

    2015-11-01

    The present article reports second background considerations for the experimentally obtained 2H(7Be,3H)6Be differential cross sections. The one-neutron transfer reaction was measured in inverse kinematics by using radioactive 7Be ( t 1/2 = 53.2 days) beams at the Holifield Radioactive Ion Beam Facility of the Oak Ridge National Laboratory in 2004 in order to search for the resonances in the unbound 6Be nucleus. Resonances in this nucleus would affect the 3He(3He,2 p)4He reaction rate of the proton-proton chain occurring in stars such as our sun. The result shows, however, that the direct transfer to 6Be resonances is not particularly strong compared to other reaction channels that can produce tritons in the exit channels. The goals of the present work is to better understand the cross section data from transfer reaction measurements by adopting background considerations using the three-body continuum.

  12. Combined FPPE-PTR Calorimetry Involving TWRC Technique II. Experimental: Application to Thermal Effusivity Measurements of Solids

    NASA Astrophysics Data System (ADS)

    Dadarlat, Dorin; Pop, Mircea Nicolae; Streza, Mihaela; Longuemart, Stephane; Depriester, Michael; Sahraoui, Abdelhak Hadj; Simon, Viorica

    2011-10-01

    Photopyroelectric calorimetry in the front detection configuration (FPPE) and photothermal radiometry (PTR) were simultaneously used, together with the thermal-wave resonator cavity method (TWRC), in order to investigate the thermal effusivity of solids inserted as backing layers in a detection cell. A new combined FPPE-PTR-TWRC setup was designed. It was demonstrated experimentally that the PTR technique, combined with the TWRC method, is able to provide calorimetric information about the third layer of a detection cell. Applications on solids with different values of the thermal effusivity (starting from metals, down to thermal isolators) are presented. The values of the thermal effusivity obtained with the PTR technique are similar to those obtained with the PPE technique, and in agreement with literature values; the two methods reciprocally support each other. The accuracy of both methods is higher when the values of the thermal effusivity of the backing layer and coupling fluid are close.

  13. The inward bulge type buckling of monocoque cylinders II : experimental investigation of the buckling in combined bending and compression

    NASA Technical Reports Server (NTRS)

    Hoff, N J; Fuchs, S J; Cirillo, Adam J

    1944-01-01

    This paper is the second part of a series of reports on the inward bulge type buckling of monocoque cylinders. It presents the results of an experimental investigation of buckling in combined bending and compression. In the investigation it was found that the theory developed in part I of the present series predicts the buckling load in combined bending and compression with the same degree of accuracy as the older theory does in pure bending. In the realm covered by the experiments no systematic variation of the parameter N was observed. The analysis of the test results afforded a check on the theories of buckling of a curved panel. The agreement between experiment and theory was reasonably good. In addition, the effect of the end conditions upon the stress distribution under loads and upon initial stresses was investigated.

  14. Absorption of laser radiation in a H-He plasma. II - Experimental measurement of the absorption coefficient

    NASA Technical Reports Server (NTRS)

    Billman, K. W.; Rowley, P. D.; Stallcop, J. R.; Presley, L.

    1974-01-01

    The absorption coefficients of 0.633-, 1.15-, and 3.39-micron laser radiation for a homogeneous H-He plasma have been measured in the temperature range from 12.2 to 21.7 (x 1000 K) and in the electron number density range 0.45 to 6.5 (x 10 to the 17th power per cu cm). Good agreement is found between the experimentally determined total absorption for each of the wavelengths and that calculated from theory. Furthermore, because the 3.39-micron absorption is dominated by inverse bremsstrahlung, while the 0.633-micron absorption is dominated by photoionization and resonance absorption, the experiment indicates a correct assessment by the theory of these individual absorption mechanisms.

  15. Detailed Consideration of Experimental Results of Gyrotron FU CW II Developed as a Radiation Source for DNP-NMR Spectroscopy

    NASA Astrophysics Data System (ADS)

    Agusu, La; Idehara, T.; Ogawa, I.; Saito, T.; Kanemaki, T.; Takahashi, H.; Fujiwara, T.

    2007-07-01

    A CW gyrotron for the sensitivity enhancement of NMR spectroscopy through dynamic nuclear polarization has been designed. The gyrotron operates at the second harmonic and frequency of 394.6 GHz with the main operating mode TE0,6. Operating conditions of other neighboring cavity modes such as TE2,6 at frequency of 392.6 GHz and TE2,3 at frequency of 200.7 GHz were also considered. The experimental conditions of the gyrotron at low and high voltages are simulated. The output power of 56 watts corresponds to the efficiency of 2 percent at low voltage operation and frequency of 394.6 GHz is expected.

  16. Synthesis, X-ray structure, spectroscopic characterization and nonlinear optical properties of Nickel (II) complex with picolinate: A combined experimental and theoretical study

    NASA Astrophysics Data System (ADS)

    Tamer, Ömer; Avcı, Davut; Atalay, Yusuf

    2015-10-01

    A novel Nickel (II) complex with picolinate was prepared and its structural characterization was carried out by X-ray diffraction method. Its vibration spectra (FT-IR and Raman) were recorded to investigate the vibrational wavenumbers and the coordination environment of Ni(II) ion. In order to demonstrate electronic transitions and molecular charge transfers within complex 1, UV-vis spectrum was measured in ethanol solvent. Furthermore, the density functional theory (DFT) calculations were performed to both support the experimental results and convert this study to more advanced work. The geometry optimization and calculations of vibration spectra and electronic transitions were performed by using DFT level. Obtained small HOMO-LUMO energy gap displayed that complex 1 can be easily polarized and molecular charge transfer occurs within complex 1. Molecular stability and hyperconjugative interactions were investigated by applying natural bond orbital (NBO) analysis. The nonlinear optical properties of complex 1 were determined, and obtained results showed that complex 1 can be considered as a potential candidate for NLO material.

  17. Circular dichroism and optical absorption spectra of mononuclear and trinuclear chiral Cu(II) amino-alcohol coordinated compounds: A combined theoretical and experimental study

    NASA Astrophysics Data System (ADS)

    Valencia, Israel; Ávila-Torres, Yenny; Barba-Behrens, Norah; Garzón, Ignacio L.

    2015-04-01

    Studies on the physicochemical properties of biomimetic compounds of multicopper oxidases are fundamental to understand their reaction mechanisms and catalytic behavior. In this work, electronic, optical, and chiroptical properties of copper(II) complexes with amino-alcohol chiral ligands are theoretically studied by means of time-dependent density functional theory. The calculated absorption and circular dichroism spectra are compared with experimental measurements of these spectra for an uncoordinated pseudoephedrine derivative, as well as for the corresponding mononuclear and trinuclear copper(II)-coordinated complexes. This comparison is useful to gain insights into their electronic structure, optical absorption and optical activity. The optical absorption and circular dichroism bands of the pseudoephedrine derivative are located in the UV-region. They are mainly due to transitions originated from n to π anti-bonding orbitals of the alcohol and amino groups, as well as from π bonding to π anti-bonding orbitals of carboxyl and phenyl groups. In the case of the mononuclear and trinuclear compounds, additional signals in the visible spectral region are present. In both systems, the origin of these bands is due to charge transfer from ligand to metal and d-d transitions.

  18. A combined theoretical and experimental study of chelidamate cadmium (II) complex, [Cd2(dpa)2(chel)2]⋅2[Cd(dpa)(chel)]⋅6H2O.

    PubMed

    Vural, Hatice; Uçar, Ibrahim

    2014-11-01

    A new chelidamate complex of Cd (II) ion, [Cd2(dpa)2(chel)2]⋅2[Cd(dpa)(chel)]⋅6H2O [(chel: chelidamate or 4-hydroxypyridine-2,6-dicarboxylate, dpa: di (2-picolyl)amine)] was synthesized and characterized by spectroscopic (UV-Vis and FT-IR spectroscopy) and structural (single-crystal X-ray diffraction) methods. Quantum chemical calculations were carried out by using Hartree Fock (HF) and Density Functional Theory (DFT)/B3LYP methods Stuttgart/Dresden (SDD) basis set. The asymmetric unit of the title compound contains two symmetry unrelated monomeric units, one dimeric unit and six water molecules of crystallization. The geometries around the Cd (II) metal centers in the units can be described as distorted octahedral for the monomeric units and distorted monocapped trigonal prism for the dimeric unit. The electronic structure of the complex was calculated using time dependent DFT (TD-DFT) method with polarizable continuum model (PCM). Molecular stability and bond strength were investigated by applying natural bond orbital analysis (NBO). The computed frequencies were compared with experimental frequencies. PMID:25456672

  19. A combined theoretical and experimental study of chelidamate cadmium (II) complex, [Cd2(dpa)2(chel)2]ṡ2[Cd(dpa)(chel)]ṡ6H2O

    NASA Astrophysics Data System (ADS)

    Vural, Hatice; Uçar, İbrahim

    2015-02-01

    A new chelidamate complex of Cd (II) ion, [Cd2(dpa)2(chel)2]ṡ2[Cd(dpa)(chel)]ṡ6H2O [(chel: chelidamate or 4-hydroxypyridine-2,6-dicarboxylate, dpa: di (2-picolyl)amine)] was synthesized and characterized by spectroscopic (UV-Vis and FT-IR spectroscopy) and structural (single-crystal X-ray diffraction) methods. Quantum chemical calculations were carried out by using Hartree Fock (HF) and Density Functional Theory (DFT)/B3LYP methods Stuttgart/Dresden (SDD) basis set. The asymmetric unit of the title compound contains two symmetry unrelated monomeric units, one dimeric unit and six water molecules of crystallization. The geometries around the Cd (II) metal centers in the units can be described as distorted octahedral for the monomeric units and distorted monocapped trigonal prism for the dimeric unit. The electronic structure of the complex was calculated using time dependent DFT (TD-DFT) method with polarizable continuum model (PCM). Molecular stability and bond strength were investigated by applying natural bond orbital analysis (NBO). The computed frequencies were compared with experimental frequencies.

  20. An atlas of DNA methylation in diverse bovine tissues

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We launched an effort to produce a reference cattle DNA methylation resource to improve animal production. We will employ experimental pipelines built around next generation sequencing technologies to map DNA methylation in cultured cells and primary tissues systems frequently involved in animal pro...

  1. Analyses of cattle DNA methylation patterns in diverse tissues

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We launched an effort to produce a reference cattle DNA methylation resource to improve animal production. We will employ experimental pipelines built around next generation sequencing technologies to map DNA methylation in culture cells and primary tissues systems frequently involved in animal prod...

  2. Structural, vibrational, and electronic properties of an uncoordinated pseudoephedrine derivative and its mononuclear and trinuclear copper(II)-coordinated compounds: A combined theoretical and experimental study

    NASA Astrophysics Data System (ADS)

    Valencia, Israel; Ávila-Torres, Yenny; Barba-Behrens, Norah; Garzón, Ignacio L.

    2014-11-01

    Multicopper oxidases are fundamental in a variety of biological processes in bacteria, fungi and vertebrates. The catalytic center in these enzymes is formed basically by three copper ions, bridged by oxygen bonds. In order to get insights into the reactivity of these complex systems, biomimetic compounds are usually synthesized. Accordingly, in this work, we studied structural, vibrational, and electronic properties of an uncoordinated pseudoephedrine derivative, as well as its corresponding mononuclear and trinuclear copper(II)-coordinated complexes by means of density functional theory. The calculations are compared with experimental results using measurements of the infrared spectra. It is obtained that the molecular configuration of the pseudoephedrine amino-alcohol derivative is stabilized by hydrogen bonding Osbnd H⋯N and by Csbnd H⋯π interactions that are not present in the mononuclear and trinuclear compounds. The coordination compounds show octahedral and square pyramid geometries, respectively, which are slightly distorted by Jahn-Teller effects. The analysis of their theoretical and experimental IR spectra reveals signals related with hydrogen bonding as well as metal-ligand vibrational modes. Regarding the electronic structure, the density of states was calculated in order to analyze the atomic orbital contributions present in these compounds. This analysis would provide useful insights about the optical behavior, for example, in the visible region of the spectrum of the coordinated compounds. At these energies, the optical absorption would be influenced by the orbital interaction of the Cu2+d orbitals with sp ones of the ligand, reflecting a decrease of the HOMO-LUMO gap of the organic ligand due to the presence of the copper(II) ions.

  3. Crystal structure of aqua­{μ-N-[3-(di­methyl­amino)­prop­yl]-N′-2-(oxidophen­yl)oxamidato}(1,10-phen­anthroline-5,6-dione)dicopper(II) perchlorate hemihydrate

    PubMed Central

    Zhang, Xin; Li, Yan-Tuan; Wu, Zhi-Yong

    2015-01-01

    The title compound, [Cu2(C13H16N3O3)(C12H6N2O2)(H2O)]ClO4·0.5H2O, consists of a cis-oxamide-bridged binuclear CuII complex cation, a perchlorate anion and half a solvent water mol­ecule. One CuII cation is N,N′,N",O-chelated by an N-[3-(di­methyl­amino)­prop­yl]-N′-(2-hy­droxy­phen­yl)oxamide trianion in a distorted square-planar geometry, whereas the other CuII cation is O,O′-chelated by the oxamide moiety of the anion and N,N′-chelated by a 1,10-phenanthroline-5,6-dione mol­ecule, and a water mol­ecule further coordinates the second CuII cation, completing a distorted square-pyramidal coordination geometry. In the crystal, classical O—H⋯O hydrogen bonds, weak C—H⋯O hydrogen-bonding inter­actions and π–π stacking inter­actions link the complex cations, anions and solvent water mol­ecules into a three-dimensional supra­molecular architecture. In the crystal, the di­methyl­amino­propyl unit of the oxamide anion is disordered over two positions with an occupancy ratio of 0.561 (11):0.439 (11); the solvent water mol­ecule is also disordered over two positions, the occupancy ratio being 0.207 (10):0.293 (10). PMID:26090146

  4. Carbon Monoxide (CO) Released from Tricarbonyldichlororuthenium (II) Dimer (CORM-2) in Gastroprotection against Experimental Ethanol-Induced Gastric Damage

    PubMed Central

    Magierowska, Katarzyna; Magierowski, Marcin; Hubalewska-Mazgaj, Magdalena; Adamski, Juliusz; Surmiak, Marcin; Sliwowski, Zbigniew; Kwiecien, Slawomir; Brzozowski, Tomasz

    2015-01-01

    The physiological gaseous molecule, carbon monoxide (CO) becomes a subject of extensive investigation due to its vasoactive activity throughout the body but its role in gastroprotection has been little investigated. We determined the mechanism of CO released from its donor tricarbonyldichlororuthenium (II) dimer (CORM-2) in protection of gastric mucosa against 75% ethanol-induced injury. Rats were pretreated with CORM-2 30 min prior to 75% ethanol with or without 1) non-selective (indomethacin) or selective cyclooxygenase (COX)-1 (SC-560) and COX-2 (celecoxib) inhibitors, 2) nitric oxide (NO) synthase inhibitor L-NNA, 3) ODQ, a soluble guanylyl cyclase (sGC) inhibitor, hemin, a heme oxygenase (HO)-1 inductor or zinc protoporphyrin IX (ZnPPIX), an inhibitor of HO-1 activity. The CO content in gastric mucosa and carboxyhemoglobin (COHb) level in blood was analyzed by gas chromatography. The gastric mucosal mRNA expression for HO-1, COX-1, COX-2, iNOS, IL-4, IL-1β was analyzed by real-time PCR while HO-1, HO-2 and Nrf2 protein expression was determined by Western Blot. Pretreatment with CORM-2 (0.5–10 mg/kg) dose-dependently attenuated ethanol-induced lesions and raised gastric blood flow (GBF) but large dose of 100 mg/kg was ineffective. CORM-2 (5 mg/kg and 50 mg/kg i.g.) significantly increased gastric mucosal CO content and whole blood COHb level. CORM-2-induced protection was reversed by indomethacin, SC-560 and significantly attenuated by celecoxib, ODQ and L-NNA. Hemin significantly reduced ethanol damage and raised GBF while ZnPPIX which exacerbated ethanol-induced injury inhibited CORM-2- and hemin-induced gastroprotection and the accompanying rise in GBF. CORM-2 significantly increased gastric mucosal HO-1 mRNA expression and decreased mRNA expression for iNOS, IL-1β, COX-1 and COX-2 but failed to affect HO-1 and Nrf2 protein expression decreased by ethanol. We conclude that CORM-2 released CO exerts gastroprotection against ethanol-induced gastric

  5. Stability constants and molar absorptivities for complexes of copper(II) with N-methyldiethanolamine, 1,4-bis(2-hydroxypropyl)-2-methylpiperazine, and 2-amino-2-methyl-1-propanol.

    PubMed

    Siefker, J R; Aroc, R V

    1986-09-01

    The stability constants and molar absorptivities of complexes of Cu(2+) with N-methyldiethanolamine, 1,4-bis(2-hydroxypropyl)-2-methylpiperazine, and 2-amino-2-methyl-1-propanol have been determined from spectrophotometric data for very dilute aqueous solutions. PMID:18964197

  6. Experimental study of stable imbibition displacements in a model open fracture. II. Scale-dependent avalanche dynamics.

    PubMed

    Clotet, Xavier; Santucci, Stéphane; Ortín, Jordi

    2016-01-01

    We report the results of an experimental investigation of the spatiotemporal dynamics of stable imbibition fronts in a disordered medium, in the regime of capillary disorder, for a wide range of experimental conditions. We have used silicone oils of various viscosities μ and nearly identical oil-air surface tension, and forced them to slowly invade a model open fracture at very different flow rates v. In this second part of the study we have carried out a scale-dependent statistical analysis of the front dynamics. We have specifically analyzed the influence of μ and v on the statistical properties of the velocity V_{ℓ}, the spatial average of the local front velocities over a window of lateral size ℓ. We have varied ℓ from the local scale defined by our spatial resolution up to the lateral system size L. Even though the imposed flow rate is constant, the signals V_{ℓ}(t) present very strong fluctuations which evolve systematically with the parameters μ, v, and ℓ. We have verified that the non-Gaussian fluctuations of the global velocity V_{ℓ}(t) are very well described by a generalized Gumbel statistics. The asymmetric shape and the exponential tail of those distributions are controlled by the number of effective degrees of freedom of the imbibition fronts, given by N_{eff}=ℓ/ℓ_{c} (the ratio of the lateral size of the measuring window ℓ to the correlation length ℓ_{c}∼1/sqrt[μv]). The large correlated excursions of V_{ℓ}(t) correspond to global avalanches, which reflect extra displacements of the imbibition fronts. We show that global avalanches are power-law distributed, both in sizes and durations, with robustly defined exponents-independent of μ, v, and ℓ. Nevertheless, the exponential upper cutoffs of the distributions evolve systematically with those parameters. We have found, moreover, that maximum sizes ξ_{S} and maximum durations ξ_{T} of global avalanches are not controlled by the same mechanism. While ξ_{S} are also

  7. Experimental study of stable imbibition displacements in a model open fracture. II. Scale-dependent avalanche dynamics

    NASA Astrophysics Data System (ADS)

    Clotet, Xavier; Santucci, Stéphane; Ortín, Jordi

    2016-01-01

    We report the results of an experimental investigation of the spatiotemporal dynamics of stable imbibition fronts in a disordered medium, in the regime of capillary disorder, for a wide range of experimental conditions. We have used silicone oils of various viscosities μ and nearly identical oil-air surface tension, and forced them to slowly invade a model open fracture at very different flow rates v . In this second part of the study we have carried out a scale-dependent statistical analysis of the front dynamics. We have specifically analyzed the influence of μ and v on the statistical properties of the velocity Vℓ, the spatial average of the local front velocities over a window of lateral size ℓ . We have varied ℓ from the local scale defined by our spatial resolution up to the lateral system size L . Even though the imposed flow rate is constant, the signals Vℓ(t ) present very strong fluctuations which evolve systematically with the parameters μ , v , and ℓ . We have verified that the non-Gaussian fluctuations of the global velocity Vℓ(t ) are very well described by a generalized Gumbel statistics. The asymmetric shape and the exponential tail of those distributions are controlled by the number of effective degrees of freedom of the imbibition fronts, given by Neff=ℓ /ℓc (the ratio of the lateral size of the measuring window ℓ to the correlation length ℓc˜1 /√{μ v } ). The large correlated excursions of Vℓ(t ) correspond to global avalanches, which reflect extra displacements of the imbibition fronts. We show that global avalanches are power-law distributed, both in sizes and durations, with robustly defined exponents—independent of μ , v , and ℓ . Nevertheless, the exponential upper cutoffs of the distributions evolve systematically with those parameters. We have found, moreover, that maximum sizes ξS and maximum durations ξT of global avalanches are not controlled by the same mechanism. While ξS are also determined by

  8. DNA methylation in plants.

    PubMed

    Vanyushin, B F

    2006-01-01

    DNA in plants is highly methylated, containing 5-methylcytosine (m5C) and N6-methyladenine (m6A); m5C is located mainly in symmetrical CG and CNG sequences but it may occur also in other non-symmetrical contexts. m6A but not m5C was found in plant mitochondrial DNA. DNA methylation in plants is species-, tissue-, organelle- and age-specific. It is controlled by phytohormones and changes on seed germination, flowering and under the influence of various pathogens (viral, bacterial, fungal). DNA methylation controls plant growth and development, with particular involvement in regulation of gene expression and DNA replication. DNA replication is accompanied by the appearance of under-methylated, newly formed DNA strands including Okazaki fragments; asymmetry of strand DNA methylation disappears until the end of the cell cycle. A model for regulation of DNA replication by methylation is suggested. Cytosine DNA methylation in plants is more rich and diverse compared with animals. It is carried out by the families of specific enzymes that belong to at least three classes of DNA methyltransferases. Open reading frames (ORF) for adenine DNA methyltransferases are found in plant and animal genomes, and a first eukaryotic (plant) adenine DNA methyltransferase (wadmtase) is described; the enzyme seems to be involved in regulation of the mitochondria replication. Like in animals, DNA methylation in plants is closely associated with histone modifications and it affects binding of specific proteins to DNA and formation of respective transcription complexes in chromatin. The same gene (DRM2) in Arabidopsis thaliana is methylated both at cytosine and adenine residues; thus, at least two different, and probably interdependent, systems of DNA modification are present in plants. Plants seem to have a restriction-modification (R-M) system. RNA-directed DNA methylation has been observed in plants; it involves de novo methylation of almost all cytosine residues in a region of si

  9. Experimental allergic encephalomyelitis in rhesus monkeys: II. Treatment of EAE with anti-T lymphocyte subset monoclonal antibodies.

    PubMed Central

    Van Lambalgen, R; Jonker, M

    1987-01-01

    Experimental allergic encephalomyelitis was induced in rhesus monkeys by immunization with bovine brain homogenate emulsified in complete Freund's adjuvant. Four monkeys were treated with anti-CD4 (OKT4+4A) monoclonal antibodies after the onset of clinical signs. One monkey developed a chronic-progressive course of EAE and was killed after a significantly prolonged disease of 19 days. One monkey had a relapse and survived with stable neurological signs. Two monkeys fully recovered. OKT4+4A treatment resulted in a short-term clearance of CD4+ lymphocytes and a reduction in granulocytes. Granulocytes may be attracted to the brain by chemotactic factors produced by CD4+ lymphocytes and are responsible for the development of the lethal granulocytic lesions. Clearance of CD4+ lymphocytes successfully prevented granulocytes from migrating to the brain. Nuclear magnetic resonance imaging showed extensive lesions during an acute attack, but these lesions became undetectable when the monkeys recovered. These results indicate that treatment with OKT4+4A can successfully reverse clinical signs of EAE. Four untreated monkeys and one monkey treated with OKT8F died of acute EAE within 3 days of the onset of clinical signs. Images Fig. 5 PMID:3498570

  10. Backspatter from experimental close-range shots to the head. II. Microbackspatter and the morphology of bloodstains.

    PubMed

    Karger, B; Nüsse, R; Tröger, H D; Brinkmann, B

    1997-01-01

    Backspatter is the ejection of biological material from a gunshot entrance wound against the line of fire. Backspatter of blood was investigated experimentally in transverse gunshots to the heads of calves (n = 9) from shooting distances of 0-10 cm. The resulting bloodstains were documented on white paper placed horizontally 60 cm below the impact site. The morphology of bloodstains and the distribution of microstains (diameter < 0.5 mm) is reported. The number of microbackspatter stains per gunshot varied between 39 and 262 and the maximum travelling distance was 69 cm while the vast majority of micro-droplets accumulated between 0 and 40 cm. The direction a single droplet can take comprises every possible angle between the most tangential ones to the skin surface. Microstains exclusively were circular to slightly oval. The morphology of macrobackspatter stains (diameter > 0.5 mm) varied from round to elongated with circular, drop-like and stains in the form of exclamation marks predominating. Small macrostains (0.5-4 mm) made up more than 90% of the macrostains and no systematic relationship between distance travelled and size of the stains could be established. The necessity of appropriate lighting and magnification in the investigation of surfaces for backspatter is stressed because many microstains are located in the proximity of the entrance wound where the firearm and the shooting hand are located in cases of close-range shots. PMID:9081237

  11. Structural damage detection based on stochastic subspace identification and statistical pattern recognition: II. Experimental validation under varying temperature

    NASA Astrophysics Data System (ADS)

    Lin, Y. Q.; Ren, W. X.; Fang, S. E.

    2011-11-01

    Although most vibration-based damage detection methods can acquire satisfactory verification on analytical or numerical structures, most of them may encounter problems when applied to real-world structures under varying environments. The damage detection methods that directly extract damage features from the periodically sampled dynamic time history response measurements are desirable but relevant research and field application verification are still lacking. In this second part of a two-part paper, the robustness and performance of the statistics-based damage index using the forward innovation model by stochastic subspace identification of a vibrating structure proposed in the first part have been investigated against two prestressed reinforced concrete (RC) beams tested in the laboratory and a full-scale RC arch bridge tested in the field under varying environments. Experimental verification is focused on temperature effects. It is demonstrated that the proposed statistics-based damage index is insensitive to temperature variations but sensitive to the structural deterioration or state alteration. This makes it possible to detect the structural damage for the real-scale structures experiencing ambient excitations and varying environmental conditions.

  12. Humoral immunity in experimental syphilis. II. The relationship of neutralizing factors in immune serum to acquired resistance.

    PubMed

    Bishop, N H; Miller, J N

    1976-07-01

    Evidence for a humoral mechanism in immunity to experimental syphilis was provided by the demonstration of immune rabbit serum factor(s) capable of inactivating virulent Treponema pallidum, Nichols strain, in an in vitro-in vivo neutralization test. After intratesticular infection, rabbits were bled periodically and their resistance to reinfection was determined by challenge with T. pallidum. The results of challenge showed that resistance to reinfection begins to develop by 11 days after infection, becomes complete by 3 months, and persists for at least 2 years. In the neutralization test, a mixture of treponemal suspension and serum from the infected animals was incubated anaerobically at 34 degrees C and the virulence of the treponemes was determined by intradermal inoculation into normal rabbits. Complete inactivation of treponemes by immune serum required heat-stable and heat-labile (56 degrees C, 30 min) serum components and 16 hr of incubation, and was accelerated by pre-incubation of the treponemes for 4 hr with nonimmune serum but not by 100 mug/ml of added lysozyme. Serum-neutralizing activity, first demonstrable 1 month postinfection, was quantitated by a neutralizing endpoint (NEP). A relatively close quantitative correlation was shown between the development of resistance to symptomatic reinfection and the appearance and persistence of both TPI antibody and neutralizing serum factor(s). The nature of the serum factor(s), the mechanism of treponemal inactivation, and the application of the test in assessing the immune status are discussed. PMID:778262

  13. Experimental and theoretical vibrational spectroscopic investigation of Zn(II) halide complexes of 3-aminopyridine and 3-chloropyridine

    NASA Astrophysics Data System (ADS)

    Akalin, E.; Akyuz, S.

    2011-05-01

    The aim of this study is to analyse the influence of the formation of metal-ligand bond through the ring nitrogen on the vibrational wavenumbers of pyridine derivatives, depending on the electron releasing (NH 2) or electron withdrawing (Cl) substituent, in the same position. As pyridine derivatives, 3-aminopyridine (3apy) and 3-chloropyridine (3Clpy) were used. Moreover, determination of the wavenumbers of metal-ligand bond vibrations has a separate interest. In order to investigate the influence of the counter ligand, halide, on pyridine derivative vibrations, calculations were carried out on both Zn(L) 2Cl 2and Zn(L) 2Br 2 (where L = 3-aminopyridine or 3-chloropyridine) compounds. Full assignment of the spectra is proposed and the analysis of the experimental data are supported by DFT calculations performed with B3LYP functional and the 6-311++G(d,p) basis set. The FT-IR (400-4000 cm -1) and Raman (100-3200 cm -1) spectra of compounds are recorded and are compared with that of the calculated spectra. Anharmonic corrections to the harmonic wavenumbers are done with the same method and level of theory. The coordination effects on vibrational wavenumbers of 3apy and 3Clpy were discussed by comparing the spectra of free and coordinated molecules.

  14. Methylation and Release of Mercury From the Solid Phase. What Comes First?

    NASA Astrophysics Data System (ADS)

    Regnell, O.

    2004-05-01

    It is a well-known fact that methylation leads to a dramatic increase in the bioavailability of mercury (Hg). All recent observations support the notion that Hg methylation is almost exclusively an anaerobic process. According to the reigning paradigm, methylation of Hg takes place in the cytoplasm of anaerobic bacteria, notably sulfate-reducing bacteria. It is believed that certain forms of inorganic divalent Hg (Hg(II)), can readily diffuse across the cell membrane. In addition, a recent study suggested that active uptake may occur when Hg is bound to low weight organic molecules. In the cytoplasm, cobalamin-dependent biochemical pathways, designed to methylate substrates other than Hg(II), are held responsible for the methylation of Hg(II). However, recent results from studies in a Swedish wetland (within the project "Svartsjoprojektet", aiming at understanding Hg dynamics in a Hg-polluted river-lake system) have led us to question whether Hg methylation does occur exclusively within cells. A provocative interpretation of our results is that methylation preceded the release of Hg from the solid phase, e.g. that Hg(II) sorbed to solid surfaces was methylated and subsequently released as methyl Hg to the sulfidic water. I will discuss this possibility in light of existing evidence that Hg methylation is an intra cellular process.

  15. Genetic Control of Methyl Halide Production in Arabidopsis

    NASA Astrophysics Data System (ADS)

    Rhew, R. C.; Ostergaard, L.; Saltzman, E. S.; Yanofsky, M. F.

    2003-12-01

    Methyl chloride and methyl bromide are the primary carriers of natural chlorine and bromine to the stratosphere where they catalyze the destruction of ozone, whereas methyl iodide influences aerosol formation and ozone loss in the troposphere. Methyl bromide is also an agricultural fumigant whose use is scheduled to be phased out by international agreement. Despite the economic and environmental importance of these methyl halides, their natural sources and biological production mechanisms are poorly understood. Currently identified sources include oceans, biomass burning, industrial and agricultural use, fuel combustion, salt marshes, wetlands, rice paddies, certain terrestrial plants and fungi, and abiotic processes. We demonstrate that the model plant Arabidopsis thaliana produces and emits methyl halides and that the enzyme primarily responsible for the production is encoded by the HARMLESS TO OZONE LAYER (HOL) gene located on chromosome II. In mutant plants that have a disruption of the HOL gene, methyl halide production is largely eliminated. A phylogenetic analysis using the HOL gene suggests that the ability to produce methyl halides is widespread among vascular plants. This approach provides a genetic basis for understanding and predicting patterns of methyl halide production by plants.

  16. Filtering Chromatic Aberration for Wide Acceptance Angle Electrostatic Lenses II--Experimental Evaluation and Software-Based Imaging Energy Analyzer.

    PubMed

    Fazekas, Ádám; Daimon, Hiroshi; Matsuda, Hiroyuki; Tóth, László

    2016-03-01

    Here, the experimental results of the method of filtering the effect of chromatic aberration for wide acceptance angle electrostatic lens-based system are described. This method can eliminate the effect of chromatic aberration from the images of a measured spectral image sequence by determining and removing the effect of higher and lower kinetic energy electrons on each different energy image, which leads to significant improvement of image and spectral quality. The method is based on the numerical solution of a large system of linear equations and equivalent with a multivariate strongly nonlinear deconvolution method. A matrix whose elements describe the strongly nonlinear chromatic aberration-related transmission function of the lens system acts on the vector of the ordered pixels of the distortion free spectral image sequence, and produces the vector of the ordered pixels of the measured spectral image sequence. Since the method can be applied not only on 2D real- and $k$ -space diffraction images, but also along a third dimension of the image sequence that is along the optical or in the 3D parameter space, the energy axis, it functions as a software-based imaging energy analyzer (SBIEA). It can also be applied in cases of light or other type of optics for different optical aberrations and distortions. In case of electron optics, the SBIEA method makes possible the spectral imaging without the application of any other energy filter. It is notable that this method also eliminates the disturbing background significantly in the present investigated case of reflection electron energy loss spectra. It eliminates the instrumental effects and makes possible to measure the real physical processes better. PMID:26863662

  17. Micromorphological Aspects of Forensic Geopedology II: Ultramicroscopic vs Microscopic Characterization of Phosphatic Impregnations on Soil Particles in Experimental Burials

    NASA Astrophysics Data System (ADS)

    Ern, S. I. E.; Trombino, L.; Cattaneo, C.

    2012-04-01

    Grows up the importance of the role played by soil scientists in the modern forensic sciences, in particular when buried human remains strongly decomposed or skeletonized are found in different environment situations. Among the different techniques normally used in geopedology, it is usefull to apply in such forensic cases, soil micromorphology (including optical microscopy and ultramicroscopy) that has been underused up today, for various kind of reasons. An interdisciplinary Italian-team, formed by earth scientists and legal medicine, is working on several sets of experimental burial of pigs and piglets in different soil types and for different times of burial, in order to get new evidences on environmental behaviour related to the burial, focalising on geopedological and micropedological aspects. The present work is focused on: - ultramicroscopic (SEM-EDS) characterization of the phosphatic impregnation (by body fluids) on soils sampled under the dead bodies of five couples of pigs, buried respectively for one month, six month, one year, two years and two years and half in two different areas; - microscopic (petrographic microscope) and ultramicroscopic (SEM-EDS) cross characterization of the phosphatic impregnation (by body fluids) on soils sampled under the dead bodies of several piglets, buried for twenty months. The first results show trends of persistency of such phosphatic features, mainly related to the grain size of the impregnated soil particles and weather conditions (or seasons) of exhumation, while apparently time since burial is only marginally effective for the investigated burial period. Further experiments are in progress in order to clarify the pathways of phosphorus precipitation and leaching for longer times of burial and different seasons of exhumation, both from the microscopic and the pedological/chemical point of view.

  18. Combined theoretical and experimental studies on the molecular structure, spectral and Hirshfeld surface studies of NLO tris(thiourea)zinc(II) sulfate crystals

    NASA Astrophysics Data System (ADS)

    Muthu, K.; Meenatchi, V.; Rajasekar, M.; Aditya Prasad, A.; Meena, K.; Agilandeshwari, R.; Kanagarajan, V.; Meenakshisundaram, SP.

    2015-07-01

    Transparent single crystals of tris(thiourea)zinc(II) sulfate (ZTS) were grown by slow evaporation technique at room temperature from an aqueous solution containing zinc sulfate and thiourea in the molar ratio 1:3. The experimental and theoretical studies on the molecular structure and vibrational spectra of ZTS were investigated by single crystal X-ray diffraction, FT-IR and density functional theory (DFT). The recorded X-ray diffraction bond parameters are compared with theoretical values calculated at B3LYP/LANL2DZ level. The observed vibrational patterns were compared with the computed wave numbers. The energy and oscillator strength calculated by TD-DFT results complement with the experimental findings. The first-order molecular hyperpolarizability, polarizability, dipole moment and HOMO-LUMO band gap energies were derived. The molecular stability and bond strength were investigated by applying the natural bond orbital analysis (NBO). Information about the size, shape, charge density distribution and site of chemical reactivity of the molecule has been obtained by mapping electron density with molecular electrostatic potential (MEP) using the same level of basis set. Intermolecular hydrogen bonding was investigated by means of the Hirshfeld surfaces, and the role of the Nsbnd H⋯O interactions as driving force for crystal structure formation has been demonstrated. The percentages of hydrogen bonding interactions are analyzed by Fingerprint plots of Hirshfeld surface.

  19. Experimental characterization and macro-modeling of mechanical strength of multi-sheets and multi-materials spot welds under pure and mixed modes I and II

    NASA Astrophysics Data System (ADS)

    Chtourou, Rim; Haugou, Gregory; Leconte, Nicolas; Zouari, Bassem; Chaari, Fahmi; Markiewicz, Eric

    2015-09-01

    Resistance Spot Welding (RSW) of multiple sheets with multiple materials are increasingly realized in the automotive industry. The mechanical strength of such new generation of spot welded assemblies is not that much dealt with. This is true in particular for experiments dedicated to investigate the mechanical strength of spot weld made by multi sheets of different grades, and their macro modeling in structural computations. Indeed, the most published studies are limited to two sheet assemblies. Therefore, in the first part of this work an advanced experimental set-up with a reduced mass is proposed to characterize the quasi-static and dynamic mechanical behavior and rupture of spot weld made by several sheets of different grades. The proposed device is based on Arcan test, the plates contribution in the global response is, thus, reduced. Loading modes I/II are, therefore, combined and well controlled. In the second part a simplified spot weld connector element (macroscopic modeling) is proposed to describe the nonlinear response and rupture of this new generation of spot welded assemblies. The weld connector model involves several parameters to be set. The remaining parameters are finally identified through a reverse engineering approach using mechanical responses of experimental tests presented in the first part of this work.

  20. Advances in light-induced polymerizations: I. Shadow cure in free radical photopolymerizations II. Experimental and modeling studies of photoinitiator systems for effective polymerizations with LEDs

    NASA Astrophysics Data System (ADS)

    Kitano, Hajime

    Photopolymerization has become the standard for many coating and printing applications that require rapid curing at room temperature due to its potential to reduce volatile organic compound (VOC) emissions while providing a means for efficient manufacturing processes. These advantages could be useful in a variety of emerging applications, such as anisotropic conductive films (ACF) if photopolymerization could extend into relatively narrow shadow regions which are not directly illuminated, and if visible wavelengths that are not absorbed by polyimide films could be used to trigger the reaction. The broad objectives of this research are i) to examine the factors that determine the attainable extent of shadow cure in free radical polymerizations, and ii) to develop initiator systems effective for polymerization using visible light and light emitting diode (LED) lamps. Project I: Shadow Cure in Free Radical Photopolymerizations. In this project, the extent of shadow cure in visible-light-induced free radical photopolymerization is investigated. A number of effective methods such as adding additives, utilizing a reflective stage, and increasing the light intensity are introduced. In addition, the use of fluorescent dyes in multi-component photoinitiator systems proved to be very effective for shadow cure because the fluorescent light emitted from the dye could irradiate the shadow region. When considering practical resins, mixtures of oligomers and monomers, the viscosity is the major barrier that must be overcome in order to achieve high conversion in the shadow regions using visible-light-induced multi-component photoinitiator systems. Hence, instead of using multi-component systems, a commercial visible-light-induced single-component photoinitiator is investigated. As a result, a high conversion in shadow regions of the viscous oligomer containing resin is achieved. Project II: Experimental and Modeling Studies of Photoinitiator Systems for Effective Polymerizations

  1. Improved Experimental and Computational Methodology for Determining the Kinetic Equation and the Extant Kinetic Constants of Fe(II) Oxidation by Acidithiobacillus ferrooxidans▿

    PubMed Central

    Molchanov, Sharon; Gendel, Yuri; Ioslvich, Ilya; Lahav, Ori

    2007-01-01

    The variety of kinetics expressions encountered in the literature and the unreasonably broad range of values reported for the kinetics constants of Acidithiobacillus ferrooxidans underscore the need for a unifying experimental procedure and for the development of a reliable kinetics equation. Following an extensive and critical review of reported experimental techniques, a method based on batch pH-controlled kinetics experiments lasting less than one doubling time was developed for the determination of extant kinetics constants. The Fe(II) concentration in the experiments was measured by a method insensitive to Fe(III) interference. Kinetics parameters were determined by nonlinear fitting of the integrated form of the Monod equation to yield a KS of 31 ± 4 mg Fe2+ liter−1 (mean ± standard deviation), a KP of 139 ± 20 mg Fe3+ liter−1, and a μmax of 0.082 ± 0.002 h−1. The corresponding kinetics equation was as follows: \\documentclass[10pt]{article} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{pmc} \\pagestyle{empty} \\oddsidemargin -1.0in \\begin{document} \\begin{equation*}\\frac{dS}{dt}= \\left \\left(-\\frac{0.082}{2.3{\\cdot}10^{7}}\\right) \\right \\frac{S{\\cdot}X}{31(1+\\displaystyle\\frac{P_{0}+S_{0}-S}{139})+S}\\end{equation*}\\end{document} where S represents the Fe(II) concentration in mg liter−1, P0 represents the initial Fe(III) concentration in mg liter−1, X represents the suspended bacterial cell concentration in cells ml−1, and t represents time in hours. The measured data fit this equation exceptionally well, with an R2 of >0.99. Fe(III) inhibition was found to be of a competitive nature. Contrary to previous reports, the results show that the concentration of Acidithiobacillus ferrooxidans cells has no affect on the kinetics constants. The kinetics equation can be considered applicable only to A. ferrooxidans cells grown under

  2. Experimental study of the hydrothermal reactivity of organic acids and acid anions: II. Acetic acid, acetate, and valeric acid

    NASA Astrophysics Data System (ADS)

    McCollom, Thomas M.; Seewald, Jeffrey S.

    2003-10-01

    Organic acids and acid anions occur in substantial concentrations in many aqueous geologic fluids and are thought to take part in a variety of geochemical processes ranging from the transport of metals in ore-forming fluids to the formation of natural gas to serving as a metabolic energy source for microbes in subsurface habitats. The widespread occurrence of organic acids and their potential role in diverse geologic processes has led to numerous experimental studies of their thermal stability, yet there remain substantial gaps in our knowledge of the factors that control the rates and reaction pathways for the decomposition of these compounds under geologic conditions. In order to address some of these uncertainties, a series of laboratory experiments were conducted to examine the behavior of organic acids and acid anions under hydrothermal conditions in the presence of minerals. Reported here are results of experiments where aqueous solutions of acetic acid, sodium acetate, or valeric acid ( n-pentanoic acid) were heated at 325°C, 350 bars in the presence of the mineral assemblages hematite + magnetite + pyrite, pyrite + pyrrhotite + magnetite, and hematite + magnetite. The results indicate that aqueous acetic acid and acetate decompose by a combination of two reaction pathways: decarboxylation and oxidation. Both reactions are promoted by minerals, with hematite catalyzing the oxidation reaction while magnetite catalyzes decarboxylation. The oxidation reaction is much faster, so that oxidation dominates the decomposition of acetic acid and acetate when hematite is present. In contrast to previous reports that acetate decomposed more slowly than acetic acid, we found that acetate decomposed at slightly faster rates than the acid in the presence of minerals. Although longer-chain monocarboxylic acids are generally thought to decompose by decarboxylation, valeric acid appeared to decompose primarily by "deformylation" to 1-butene plus formic acid. Subsequent

  3. Doppler-broadened NICE-OHMS beyond the cavity-limited weak absorption condition - II: Experimental verification

    NASA Astrophysics Data System (ADS)

    Hausmaninger, Thomas; Silander, Isak; Ma, Weiguang; Axner, Ove

    2016-01-01

    Doppler-broadened (Db) noise-immune cavity-enhanced optical heterodyne molecular spectrometry (NICE-OHMS) is normally described by an expression, here termed the conventional (CONV) description, that is restricted to the conventional cavity-limited weak absorption condition (CCLWA), i.e. when the single pass absorbance is significantly smaller than the empty cavity losses, i.e. when α0 L < < π / F. To describe NICE-OHMS signals beyond this limit two simplified extended descriptions (termed the extended locking and extended transmission description, ELET, and the extended locking and full transmission description, ELFT), which are assumed to be valid under the relaxed cavity-limited weak absorption condition (RCLWA), i.e. when α0 L < π / F, and a full description (denoted FULL), presumed to be valid also when the α0 L < π / F condition does not hold, have recently been derived in an accompanying work (Ma W, et al. Doppler-broadened NICE-OHMS beyond the cavity-limited weak absorption condition - I. Theoretical Description. J Quant Spectrosc Radiat Transfer, 2015, http://dx.doi.org/10.1016/j.jqsrt.2015.09.007). The present work constitutes an experimental verification and assessment of the validity of these, performed in the Doppler limit for a set of Fα0 L / π values (up to 3.5); it is shown under which conditions the various descriptions are valid. It is concluded that for samples with Fα0 L / π up to 0.01, all descriptions replicate the data well. It is shown that the CONV description is adequate and provides accurate assessments of the signal strength (and thereby the analyte concentration) up to Fα0 L / π of around 0.1, while the ELET is accurate for Fα0 L / π up to around 0.3. The ELFT description mimics the Db NICE-OHMS signal well for Fα0 L / π up to around unity, while the FULL description is adequate for all Fα0 L / π values investigated. Access to these descriptions both increases considerably the dynamic range of the technique and

  4. Ab initio structural modeling of and experimental validation for Chlamydia trachomatis protein CT296 reveal structural similarity to Fe(II) 2-oxoglutarate-dependent enzymes

    SciTech Connect

    Kemege, Kyle E.; Hickey, John M.; Lovell, Scott; Battaile, Kevin P.; Zhang, Yang; Hefty, P. Scott

    2012-02-13

    Chlamydia trachomatis is a medically important pathogen that encodes a relatively high percentage of proteins with unknown function. The three-dimensional structure of a protein can be very informative regarding the protein's functional characteristics; however, determining protein structures experimentally can be very challenging. Computational methods that model protein structures with sufficient accuracy to facilitate functional studies have had notable successes. To evaluate the accuracy and potential impact of computational protein structure modeling of hypothetical proteins encoded by Chlamydia, a successful computational method termed I-TASSER was utilized to model the three-dimensional structure of a hypothetical protein encoded by open reading frame (ORF) CT296. CT296 has been reported to exhibit functional properties of a divalent cation transcription repressor (DcrA), with similarity to the Escherichia coli iron-responsive transcriptional repressor, Fur. Unexpectedly, the I-TASSER model of CT296 exhibited no structural similarity to any DNA-interacting proteins or motifs. To validate the I-TASSER-generated model, the structure of CT296 was solved experimentally using X-ray crystallography. Impressively, the ab initio I-TASSER-generated model closely matched (2.72-{angstrom} C{alpha} root mean square deviation [RMSD]) the high-resolution (1.8-{angstrom}) crystal structure of CT296. Modeled and experimentally determined structures of CT296 share structural characteristics of non-heme Fe(II) 2-oxoglutarate-dependent enzymes, although key enzymatic residues are not conserved, suggesting a unique biochemical process is likely associated with CT296 function. Additionally, functional analyses did not support prior reports that CT296 has properties shared with divalent cation repressors such as Fur.

  5. Experimental and quantum-chemical studies of 1H, 13C and 15N NMR coordination shifts in Pd(II) and Pt(II) chloride complexes with quinoline, isoquinoline, and 2,2'-biquinoline.

    PubMed

    Pazderski, Leszek; Tousek, Jaromír; Sitkowski, Jerzy; Kozerski, Lech; Szłyk, Edward

    2007-12-01

    1H, 13C, and 15N NMR studies of platinide(II) (M=Pd, Pt) chloride complexes with quinolines (L=quinoline-quin, or isoquinoline-isoquin; LL=2,2'-biquinoline-bquin), having the general formulae trans-/cis-[ML2Cl2] and [M(LL)Cl2], were performed and the respective chemical shifts (delta1H, delta13C, delta15N) reported. 1H coordination shifts of various signs and magnitudes (Delta1Hcoord=delta1Hcomplex-delta1Hligand) are discussed in relation to the changes of diamagnetic contribution to the relevant 1H shielding constants. The comparison to the literature data for similar complexes containing auxiliary ligands other than chlorides exhibited a large dependence of delta1H parameters on electron density variations and ring-current effects (inductive and anisotropic phenomena). The influence of deviations from planarity, concerning either MN2Cl2 chromophores or azine ring systems, revealed by the known X-ray structures of [Pd(bquin)Cl2] and [Pt(bquin)Cl2], is discussed in respect to 1H NMR spectra. 15N coordination shifts (Delta15Ncoord=delta15Ncomplex-delta15Nligand) of ca. 78-100 ppm (to lower frequency) are attributed mainly to the decrease of the absolute value of paramagnetic contribution in the relevant 15N shielding constants, this phenomenon being noticeably dependent on the type of a platinide metal and coordination sphere geometry. The absolute magnitude of Delta15Ncoord parameter increased by ca 15 ppm upon Pd(II)-->Pt(II) replacement but decreased by ca. 15 ppm following trans-->cis transition. Experimental 1H, 13C, 15N NMR chemical shifts are compared to those quantum-chemically calculated by B3LYP/LanL2DZ+6-31G**//B3LYP/LanL2DZ+6-31G*, both in vacuo and in CHCl3 or DMF solution. PMID:18044805

  6. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... substituted methyl styrene, methyl methacrylate, and substituted silane. 721.6920 Section 721.6920 Protection... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

  7. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... substituted methyl styrene, methyl methacrylate, and substituted silane. 721.6920 Section 721.6920 Protection... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

  8. 40 CFR 721.6920 - Butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... substituted methyl styrene, methyl methacrylate, and substituted silane. 721.6920 Section 721.6920 Protection... acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted silane. (a... butyl acrylate, polymer with substituted methyl styrene, methyl methacrylate, and substituted...

  9. Statistical model based iterative reconstruction (MBIR) in clinical CT systems. Part II. Experimental assessment of spatial resolution performance

    PubMed Central

    Li, Ke; Garrett, John; Ge, Yongshuai; Chen, Guang-Hong

    2014-01-01

    Purpose: Statistical model based iterative reconstruction (MBIR) methods have been introduced to clinical CT systems and are being used in some clinical diagnostic applications. The purpose of this paper is to experimentally assess the unique spatial resolution characteristics of this nonlinear reconstruction method and identify its potential impact on the detectabilities and the associated radiation dose levels for specific imaging tasks. Methods: The thoracic section of a pediatric phantom was repeatedly scanned 50 or 100 times using a 64-slice clinical CT scanner at four different dose levels [CTDIvol =4, 8, 12, 16 (mGy)]. Both filtered backprojection (FBP) and MBIR (Veo®, GE Healthcare, Waukesha, WI) were used for image reconstruction and results were compared with one another. Eight test objects in the phantom with contrast levels ranging from 13 to 1710 HU were used to assess spatial resolution. The axial spatial resolution was quantified with the point spread function (PSF), while the z resolution was quantified with the slice sensitivity profile. Both were measured locally on the test objects and in the image domain. The dependence of spatial resolution on contrast and dose levels was studied. The study also features a systematic investigation of the potential trade-off between spatial resolution and locally defined noise and their joint impact on the overall image quality, which was quantified by the image domain-based channelized Hotelling observer (CHO) detectability index d′. Results: (1) The axial spatial resolution of MBIR depends on both radiation dose level and image contrast level, whereas it is supposedly independent of these two factors in FBP. The axial spatial resolution of MBIR always improved with an increasing radiation dose level and/or contrast level. (2) The axial spatial resolution of MBIR became equivalent to that of FBP at some transitional contrast level, above which MBIR demonstrated superior spatial resolution than FBP (and vice

  10. Statistical model based iterative reconstruction (MBIR) in clinical CT systems. Part II. Experimental assessment of spatial resolution performance

    SciTech Connect

    Li, Ke; Chen, Guang-Hong; Garrett, John; Ge, Yongshuai

    2014-07-15

    Purpose: Statistical model based iterative reconstruction (MBIR) methods have been introduced to clinical CT systems and are being used in some clinical diagnostic applications. The purpose of this paper is to experimentally assess the unique spatial resolution characteristics of this nonlinear reconstruction method and identify its potential impact on the detectabilities and the associated radiation dose levels for specific imaging tasks. Methods: The thoracic section of a pediatric phantom was repeatedly scanned 50 or 100 times using a 64-slice clinical CT scanner at four different dose levels [CTDI{sub vol} =4, 8, 12, 16 (mGy)]. Both filtered backprojection (FBP) and MBIR (Veo{sup ®}, GE Healthcare, Waukesha, WI) were used for image reconstruction and results were compared with one another. Eight test objects in the phantom with contrast levels ranging from 13 to 1710 HU were used to assess spatial resolution. The axial spatial resolution was quantified with the point spread function (PSF), while the z resolution was quantified with the slice sensitivity profile. Both were measured locally on the test objects and in the image domain. The dependence of spatial resolution on contrast and dose levels was studied. The study also features a systematic investigation of the potential trade-off between spatial resolution and locally defined noise and their joint impact on the overall image quality, which was quantified by the image domain-based channelized Hotelling observer (CHO) detectability index d′. Results: (1) The axial spatial resolution of MBIR depends on both radiation dose level and image contrast level, whereas it is supposedly independent of these two factors in FBP. The axial spatial resolution of MBIR always improved with an increasing radiation dose level and/or contrast level. (2) The axial spatial resolution of MBIR became equivalent to that of FBP at some transitional contrast level, above which MBIR demonstrated superior spatial resolution than

  11. Methyl salicylate overdose

    MedlinePlus

    Deep heating rubs overdose; Oil of wintergreen overdose ... These products contain methyl salicylate: Deep-heating creams used to relieve sore muscles and joints (Ben Gay, Icy Hot) Oil of wintergreen Solutions for vaporizers Other products ...

  12. Analysis of DNA Methylation in Various Swine Tissues

    PubMed Central

    Niu, Weiping; Yang, Runjun; Zhang, Yonghong; Qiu, Zhengyan; Sun, Boxing; Zhao, Zhihui

    2011-01-01

    DNA methylation is known to play an important role in regulating gene expression during biological development and tissue differentiation in eukaryotes. In this study, we used the fluorescence-labeled methylation-sensitive amplified polymorphism (F-MSAP) method to assess the extent and pattern of cytosine methylation in muscle, heart, liver, spleen, lung, kidney and stomach from the swine strain Laiwu, and we also examined specific methylation patterns in the seven tissues. In total, 96,371 fragments, each representing a recognition site cleaved by either or both EcoRI + HpaII and EcoRI + MspI, the HpaII and MspI are isoschizomeric enzymes, were amplified using 16 pairs of selective primers. A total of 50,094 sites were found to be methylated at cytosines in seven tissues. The incidence of DNA methylation was approximately 53.99% in muscle, 51.24% in the heart, 50.18% in the liver, 53.31% in the spleen, 51.97% in the lung, 51.15% in the kidney and 53.39% in the stomach, as revealed by the incidence of differential digestion. Additionally, differences in DNA methylation levels imply that such variations may be related to specific gene expression during tissue differentiation, growth and development. Three types of bands were generated in the F-MSAP profile, the total numbers of these three types of bands in the seven tissues were 46,277, 24,801 and 25,293, respectively. In addition, different methylation patterns were observed in seven tissues from pig, and almost all of the methylation patterns detected by F-MSAP could be confirmed by Southern analysis using the isolated amplified fragments as probes. The results clearly demonstrated that the F-MSAP technique can be adapted for use in large-scale DNA methylation detection in the pig genome. PMID:21283691

  13. Progression of Prostate Carcinogenesis and Dietary Methyl Donors: Temporal Dependence

    PubMed Central

    Shabbeer, Shabana; Williams, Simon A.; Simons, Brian W.; Herman, James G.; Carducci, Michael A.

    2011-01-01

    Insufficient dose of dietary methyl groups are associated with a host of conditions ranging from neural tube defects to cancer. On the other hand, it is not certain what effect excess dietary methyl groups could have on cancer. This is especially true for prostate cancer (PCa), a disease that is characterized by increasing DNA methylation changes with increasing grade of the cancer. In this three-part study in animals, we look at (i) the effect of excess methyl donors on the growth rate of PCa in vivo, (ii) the ability of 5-aza-2'-deoxycytidine, a demethylating agent, to demethylate in the presence of excess dietary methyl donors and (iii) the effect of in utero feeding of excess methyl donors to the later onset of PCa. The results show that when mice are fed a dietary excess of methyl donors, we do not see (i) an increase in the growth rate of DU-145 and PC-3 xenografts in vivo, or (ii) interference in the ability of 5-aza-2'-deoxycytidine to demethylate the promoters of Androgen Receptor or Reprimo of PCa xenografts but (iii) a protective effect on the development of higher grades of PCa in the “Hi-myc” mouse model of PCa which were fed the increased methyl donors in utero. We conclude that the impact of dietary methyl donors on PCa progression depends upon the timing of exposure to the dietary agents. When fed before the onset of cancer, i.e. in utero, excess methyl donors can have a protective effect on the progression of cancer. PMID:22139053

  14. The metal complexes of heterocyclic β-diketones and their derivatives—VI. The synthesis, structure and i.r. spectral studies of some new metal(II) complexes of 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5 (HPMBP)

    NASA Astrophysics Data System (ADS)

    Okafor, Emmanuel Chukwuemeka

    The monovalent metal complex of Na and the divalent metal complexes of Be, Mn, Co, Ni, Cu, Zn, Mg, Ba, Hg and Pb with 1-phenyl-3-methyl-4-benzoyl-pyrazolone-5 (HPMBP), have been synthesized. It is shown that HPMBP behaves like a bidentate enol forming neutral metal chelates through the carbonyl and enolic hydroxyl groups. Characterization of the complexes were by means of elemental analyses, conductivity measurements, i.r. and proton NMR spectroscopy. The i.r. spectra were recorded between 4000 and 200 cm -1 and assignments are proposed for the observed frequencies. Replacement of the methyl group of the 4-acetyl moiety by the phenyl group in the metal chelates of 1-phenyl-3-methyl-4-acetyl-pyrazolone-5 (HPMAP), is found to decrease the C ?O, C ?C and MO stretching frequencies of the chelate ring. The magnitudes of the MO stretching frequencies for the transition metals show good agreement with the Irving—Williams stability order Cu>Ni>Co>Zn>Mn.

  15. Electrorefining of copper from a cuprous ion complexing electrolyte. II. Experimental comparison of possible alternative electrolytes and preliminary cost engineering analysis

    SciTech Connect

    Brown, A.P.; Loutfy, R.O.; Cook, G.M.

    1980-04-01

    The energy saving potential and refining capability of three copper(I)/electrolyte systems for the electrorefining of copper were compared experimentally. The alternative electrolyte systems studied were copper(I)/acid chloride, copper(I)/acetonitrile and sulfuric acid, and copper(I)/ammonia solutions. These were compared to the conventional copper(II)/sulfuric acid electrolyte. All of the alternative electrolyte systems demonstrated at least some potential for saving energy when run at an equal deposition rate to the conventional process; the chloride electrolyte showed the greatest energy saving potential, about 70%, and the ammonia electrolyte showed the least, about 25%. All of the alternative electrolyte systems, however, exhibited performance problems, primarily with regard to inadequate separation of impurities. A preliminary capital cost estimate was made for the copper(I)/chloride system. This estimate showed that, for the alternative electrolyte system to be cost competitive (that is, a reduction of capital cost of about 15 to 20%) with the conventional electrorefining process, the refining cells would have to be operated at a current density of about 25 to 30 mA-cm/sup -2/. At this current density, the estimated energy saving potential for the copper(I)/chloride system was still about 50%.

  16. The TcI and TcII Trypanosoma cruzi experimental infections induce distinct immune responses and cardiac fibrosis in dogs

    PubMed Central

    Duz, Ana Luiza Cassin; Vieira, Paula Melo de Abreu; Roatt, Bruno Mendes; Aguiar-Soares, Rodrigo Dian Oliveira; Cardoso, Jamille Mirelle de Oliveira; de Oliveira, Flávia Carvalho Bitencourt; Reis, Levi Eduardo Soares; Tafuri, Washington Luiz; Veloso, Vanja Maria; Reis, Alexandre Barbosa; Carneiro, Cláudia Martins

    2014-01-01

    Trypanosoma cruzi infection may be caused by different strains with distinct discrete typing units (DTUs) that can result in variable clinical forms of chronic Chagas disease. The present study evaluates the immune response and cardiac lesions in dogs experimentally infected with different T. cruzi strains with distinct DTUs, namely, the Colombian (Col) and Y strains of TcI and TcII DTU, respectively. During infection with the Col strain, increased levels of alanine aminotransferase, erythrocytes, haematocrit and haemoglobin were observed. In addition, CD8+ T-lymphocytes isolated from the peripheral blood produced higher levels of interleukin (IL)-4. The latter suggests that during the acute phase, infection with the Col strain may remain unnoticed by circulating mononuclear cells. In the chronic phase, a significant increase in the number of inflammatory cells was detected in the right atrium. Conversely, infection with the Y strain led to leucopoenia, thrombopoenia, inversion of the ratio of CD4+/CD8+ T-lymphocytes and alterations in monocyte number. The Y strain stimulated the production of interferon-γ by CD4+ and CD8+ T-lymphocytes and IL-4 by CD8+ T-cells. In the chronic phase, significant heart inflammation and fibrosis were observed, demonstrating that strains of different DTUs interact differently with the host. PMID:25591108

  17. Modeling of the oxidation of methyl esters - Validation for methyl hexanoate, methyl heptanoate, and methyl decanoate in a jet-stirred reactor

    SciTech Connect

    Glaude, Pierre Alexandre; Herbinet, Olivier; Bax, Sarah; Biet, Joffrey; Warth, Valerie; Battin-Leclerc, Frederique

    2010-11-15

    The modeling of the oxidation of methyl esters was investigated and the specific chemistry, which is due to the presence of the ester group in this class of molecules, is described. New reactions and rate parameters were defined and included in the software EXGAS for the automatic generation of kinetic mechanisms. Models generated with EXGAS were successfully validated against data from the literature (oxidation of methyl hexanoate and methyl heptanoate in a jet-stirred reactor) and a new set of experimental results for methyl decanoate. The oxidation of this last species was investigated in a jet-stirred reactor at temperatures from 500 to 1100 K, including the negative temperature coefficient region, under stoichiometric conditions, at a pressure of 1.06 bar and for a residence time of 1.5 s: more than 30 reaction products, including olefins, unsaturated esters, and cyclic ethers, were quantified and successfully simulated. Flow rate analysis showed that reactions pathways for the oxidation of methyl esters in the low-temperature range are similar to that of alkanes. (author)

  18. Modeling of the oxidation of methyl esters—Validation for methyl hexanoate, methyl heptanoate, and methyl decanoate in a jet-stirred reactor

    PubMed Central

    Glaude, Pierre Alexandre; Herbinet, Olivier; Bax, Sarah; Biet, Joffrey; Warth, Valérie; Battin-Leclerc, Frédérique

    2013-01-01

    The modeling of the oxidation of methyl esters was investigated and the specific chemistry, which is due to the presence of the ester group in this class of molecules, is described. New reactions and rate parameters were defined and included in the software EXGAS for the automatic generation of kinetic mechanisms. Models generated with EXGAS were successfully validated against data from the literature (oxidation of methyl hexanoate and methyl heptanoate in a jet-stirred reactor) and a new set of experimental results for methyl decanoate. The oxidation of this last species was investigated in a jet-stirred reactor at temperatures from 500 to 1100 K, including the negative temperature coefficient region, under stoichiometric conditions, at a pressure of 1.06 bar and for a residence time of 1.5 s: more than 30 reaction products, including olefins, unsaturated esters, and cyclic ethers, were quantified and successfully simulated. Flow rate analysis showed that reactions pathways for the oxidation of methyl esters in the low-temperature range are similar to that of alkanes. PMID:23710076

  19. Mineralisation studies of 14C-labelled metsulfuron-methyl, tribenuron-methyl, chlorsulfuron and thifensulfuron-methyl in one Danish soil and groundwater sediment profile.

    PubMed

    Andersen, S M; Hertz, P B; Holst, T; Bossi, R; Jacobsen, C S

    2001-11-01

    Bacterial mineralisation of four sulfonylurea herbicides at 20 microg kg(-1) in a sandy soil from nine different depths in a sandy soil horizon (5-780 cm) was investigated in laboratory studies. Metsulfuron-methyl, chlorsulfuron, and tribenuron-methyl were 14C-labelled in the sulfonamide ring, while thifensulfuron-methyl was labelled in the thiophene ring. The highest mineralised amount in 126 days was observed for metsulfuron-methyl (40%) followed by tribenuron-methyl (25%), and thifensulfuron-methyl (11%). Chlorsulfuron showed low mineralisation in all the soils tested (<4%). Mineralisation of the herbicides metsulfuron-methyl and tribenuron-methyl varied according to soil depth (upper profile: 5-70 cm, and lower profile: 165-780 cm) and were proven faster in soil taken from depths 5-7 and 30-35 cm, and slower in depths 45-50 and 70-75 cm. Mineralisation was absent in the lower profile (165-780 cm). As an indicator of microbial activity bacterial counts were taken at the experimental start; these counts grouped in three levels: highest in the surface layer (5-7 cm), slightly lower in the depths 30-75 cm, and lowest in the lower profile (165-780 cm). Residual concentrations of metsulfuron-methyl correlated to the accumulated amount mineralised, with high residual concentrations in soil showing low mineralisation. Also chlorsulfuron showed high residual concentrations with increasing depth in the upper profile, but the relatively high dissipation at 30-35 cm and lower one at 45-50 cm could not be related with the lack of mineralisation. This shows that hydrolysis occurs, but mineralisation of the chloro-substituted sulfonamide is restricted. Tribenuron-methyl and thifensulfuron-methyl could not be detected due to interference with other compounds. PMID:11695596

  20. Column solid phase extraction and flame atomic absorption spectrometric determination of manganese(II) and iron(III) ions in water, food and biological samples using 3-(1-methyl-1H-pyrrol-2-yl)-1H-pyrazole-5-carboxylic acid on synthesized graphene oxide.

    PubMed

    Pourjavid, Mohammad Reza; Sehat, Ali Akbari; Arabieh, Masoud; Yousefi, Seyed Reza; Hosseini, Majid Haji; Rezaee, Mohammad

    2014-02-01

    A modified, selective, highly sensitive and accurate procedure for the determination of trace amounts of manganese and iron ions is established in the presented work. 3-(1-Methyl-1H-pyrrol-2-yl)-1H-pyrazole-5-carboxylic acid (MPPC) and graphene oxide (GO) were used in a glass column as chelating reagent and as adsorbent respectively prior to their determination by flame atomic absorption spectrometry. The adsorption mechanism of titled metals complexes on GO was investigated by using computational chemistry approach based on PM6 semi-empirical potential energy surface (PES). The effect of some parameters including pH, flow rate and volume of sample and type, volume and concentration of eluent, as well as the adsorption capacity of matrix ions on the recovery of Mn(II) and Fe(III) was investigated. The limit of detection was 145 and 162 ng L(-1) for Mn(II) and Fe(III), respectively. Calibration was linear over the range of 0.31-355 μg L(-1) for Mn(II) and 0.34-380 μg L(-1) for Fe(III) ions. The method was successfully applied for the determination of understudied ions in water, food and biological samples. PMID:24411390

  1. Crystal structure of poly[(4-amino­pyridine-κN)(N,N-di­methyl­formamide-κO)(μ3-pyridine-3,5-di­carboxyl­ato-κ3 N:O 3:O 5)copper(II)

    PubMed Central

    Shen, Cheng-Chen; Hua, Xiu-Ni; Han, Lei

    2016-01-01

    The title compound, [Cu(C7H3NO4)(C5H6N2)(C3H7NO]n, is an amino-function­alized chiral metal–organic framework with (10,3)-a topology. It has been constructed via the assembly of the achiral triconnected pyridine-3,5-di­carboxyl­ate (3,5-PDC) building block and a triconnected CuII atom. Each CuII ion is coordinated by two O atoms and one N atom, respectively, of three crystallographically independent 3,5-PDC ligands. The square-pyramidal (CuN2O3) coordination geometry of the CuII ion is completed by an N atom of a terminal 4-amino­pyridine (4-APY) ligand and the O atom of a terminal N,N-di­methyl­formamide (DMF) ligand to give a triconnected ‘T’-shaped secondary building unit, which becomes trigonal in the resulting (10,3)-a topology. In the three-dimensional structure, weak N—H⋯O hydrogen bonds are observed in which the donor N—H groups are provided by the 4-APY ligands and the acceptor O atoms are provided by the non-coordinating carboxylate O atoms of the 3,5-PDC ligands. PMID:27375859

  2. DNA methylation in fibrosis.

    PubMed

    Dowson, Christopher; O'Reilly, Steven

    2016-09-01

    Fibrosis is characterised by an exuberant wound healing response and the major cell type responsible is the myofibroblast. The myofibroblast is typified by excessive ECM production and contractile activity and is demarcated by alpha-smooth muscle actin expression. What has recently come to light is that the activation of the fibroblast to myofibroblast may be under epigenetic control, specifically methylation. Methylation of DNA is a conserved mechanism to precisely regulate gene expression in a specific context. Hypermethylation leads to gene repression and hypomethylation results in gene induction. Methylation abnormalities have recently been uncovered in fibrosis, both organ specific and widespread fibrosis. The fact that these methylation changes are rapid and reversible lends themselves amenable to therapeutic intervention. This review considers the role of methylation in fibrosis and the activation of the myofibroblasts and how this could be targeted for fibrosis. Fibrosis is of course currently intractable to therapeutics and is a leading cause of morbidity and mortality and is an urgent unmet clinical need. PMID:27346523

  3. Bis(1-methyl-1H-imidazole-κN 3)[N,N′-o-phenyl­enebis(pyridine-2-carbox­amido)-κ4 N]manganese(II)

    PubMed Central

    Zahran, Zaki N.; Xu, Nan; Powell, Douglas R.; Richter-Addo, George B.

    2009-01-01

    The title compound, [Mn(C18H12N4O2)(C4H6N2)2], belongs to the family of 1,2-bis­(pyridine-2-carboxamido)benzene (H2bpb) ligated metal complexes. The manganese center is octa­hedrally coordinated by a bpb ligand and two axial 1-methyl­imidazole mol­ecules. The axial N—Mn—N group is bent with a bond angle of 151.79 (7)°. PMID:21581541

  4. An Epigenetic Mechanism of High Gdnf Transcription in Glioma Cells Revealed by Specific Sequence Methylation.

    PubMed

    Zhang, Bao-Le; Liu, Jie; Lei, Yu; Xiong, Ye; Li, Heng; Lin, Xiaoqian; Yao, Rui-Qin; Gao, Dian-Shuai

    2016-09-01

    Glioma cells express high levels of GDNF. When investigating its transcriptional regulation mechanism, we observed increased or decreased methylation of different cis-acting elements in the gdnf promoter II. However, it is difficult to determine the contributions of methylation changes of each cis-acting element to the abnormally high transcription of gdnf gene. To elucidate the contributions of methylation changes of specific cis-acting elements to the regulation of gdnf transcription, we combined gene site-directed mutation, molecular cloning, and dual luciferase assay to develop the "specific sequence methylation followed by plasmid recircularization" method to alter methylation levels of specific cis-acting elements in the gdnf promoter in living cells and assess gene transcriptional activity. This method successfully introduced artificial changes in the methylation of different cis-acting elements in the gdnf promoter II. Moreover, compared with unmethylated gdnf promoter II, both silencer II hypermethylation plus enhancer II unmethylation and hypermethylation of the entire promoter II (containing enhancer II and silencer II) significantly enhanced gdnf transcriptional activity (P < 0.05), and no significant difference was noted between these two hypermethylation patterns (P > 0.05). Enhancer II hypermethylation plus silencer II unmethylation did not significantly affect gene transcription (P > 0.05). Furthermore, we found significantly increased DNA methylation in the silencer II of the gdnf gene in high-grade astroglioma cells with abnormally high gdnf gene expression (P < 0.01). The absence of silencer II significantly increased gdnf promoter II activity in U251 cells (P < 0.01). In conclusion, our specific sequence methylation followed by plasmid recircularization method successfully altered the methylation levels of a specific cis-acting element in a gene promoter in living cells. This method allows in-depth investigation of the impact

  5. Di-μ-chlorido-bis­{[μ-1,8-bis­(diisopropyl­phosphan­yl)-9,10-dihydro-9,10-ethano­anthracene-κ2 P:P′]-μ-chlorido-μ-methyl­idene-dipalladium(II)} tetra­hydro­furan penta­solvate

    PubMed Central

    Schnetz, Thomas; Rominger, Frank; Hofmann, Peter

    2010-01-01

    The title compound, [Pd4(CH2)2Cl4(C28H40P2)2]·5C4H8O, possesses a tetra­nuclear palladium core with four bridging chlorido ligands and two bridging methyl­ene units, as well as two bridging anthracene-based bis-phosphine ligands. This tetra­nuclear complex can be considered as being composed of two μ-chlorido-bridged LPd2 units. The structural motif of these LPd2 units shows two doubly bridged palladium centers between the P atoms of the bis-phosphine ligand. One of these bridges is a μ-Cl atom, the other a μ-methyl­ene group. The coordination environment around each palladium center is essentially square planar. We ascribe the oxidation state +II to the palladium centers and do not assume Pd—Pd bonds [shortest distances 2.8110 (5) and 2.8109 (6) Å]. Co-crystallized with the palladium complex we found five non-coordinating tetra­hydro­furan solvent mol­ecules, one of which is disordered over two positions in a 0.429 (9):0.571 (8) ratio. PMID:21580540

  6. Crystal structure of [N,N′-bis­(4-methyl­phen­yl)-1,2-di­phenyl­ethane-1,2-di­imine-κ2 N,N′]di­chlorido­palladium(II) methanol monosolvate

    PubMed Central

    Peñaloza, Alfredo; Fronczek, Frank R.; Isovitsch, Ralph

    2015-01-01

    The title compound, [PdCl2(C28H24N2)]·CH3OH, was pre­pared from the reaction of PdCl2(DMSO)2 (DMSO is di­methyl sulfoxide) and N,N′-bis­(4-methyl­phen­yl)-1,2-di­phenyl­ethane-1,2-di­imine in methanol. The chelating di­imine core of the title compound deviates slightly from planarity, with an N—C—C—N torsion angle of 5.3 (3)°. Delocalization in the di­imine core is indicated by N—C and C—C bonds that are, respectively, longer and shorter than those found in related nonchelating di­imines. The distorted square-planar coordination environment around the PdII atom is manifested as bond angles that are smaller and larger than 90°, and palladacycle torsion angles of −173.22 (16) and 167.06 (16)°. These deviations are attributed to the small bite angle of 79.13 (8)° of the di­imine chelate. The crystal packing exhibits weak inter­molecular hydrogen-bonding inter­actions involving aromatic H atoms, Cl atoms and inter­calated methanol solvent mol­ecules, defining layers parallel to (010). PMID:26396867

  7. [DNA methylation in obesity].

    PubMed

    Pokrywka, Małgorzata; Kieć-Wilk, Beata; Polus, Anna; Wybrańska, Iwona

    2014-01-01

    The number of overweight and obese people is increasing at an alarming rate, especially in the developed and developing countries. Obesity is a major risk factor for diabetes, cardiovascular disease, and cancer, and in consequence for premature death. The development of obesity results from the interplay of both genetic and environmental factors, which include sedentary life style and abnormal eating habits. In the past few years a number of events accompanying obesity, affecting expression of genes which are not directly connected with the DNA base sequence (e.g. epigenetic changes), have been described. Epigenetic processes include DNA methylation, histone modifications such as acetylation, methylation, phosphorylation, ubiquitination, and sumoylation, as well as non-coding micro-RNA (miRNA) synthesis. In this review, the known changes in the profile of DNA methylation as a factor affecting obesity and its complications are described. PMID:25531701

  8. The radical mechanism of biological methane synthesis by methyl-coenzyme M reductase.

    PubMed

    Wongnate, Thanyaporn; Sliwa, Dariusz; Ginovska, Bojana; Smith, Dayle; Wolf, Matthew W; Lehnert, Nicolai; Raugei, Simone; Ragsdale, Stephen W

    2016-05-20

    Methyl-coenzyme M reductase, the rate-limiting enzyme in methanogenesis and anaerobic methane oxidation, is responsible for the biological production of more than 1 billion tons of methane per year. The mechanism of methane synthesis is thought to involve either methyl-nickel(III) or methyl radical/Ni(II)-thiolate intermediates. We employed transient kinetic, spectroscopic, and computational approaches to study the reaction between the active Ni(I) enzyme and substrates. Consistent with the methyl radical-based mechanism, there was no evidence for a methyl-Ni(III) species; furthermore, magnetic circular dichroism spectroscopy identified the Ni(II)-thiolate intermediate. Temperature-dependent transient kinetics also closely matched density functional theory predictions of the methyl radical mechanism. Identifying the key intermediate in methanogenesis provides fundamental insights to develop better catalysts for producing and activating an important fuel and potent greenhouse gas. PMID:27199421

  9. Crystal structure of the inverse crown ether tetra­kis­[μ2-bis­(tri­methyl­sil­yl)amido]-μ4-oxido-dicobalt(II)disodium, [Co2Na2{μ2-N(SiMe3)2}4](μ4-O)

    PubMed Central

    Hansen, Christopher B.; Filatov, Alexander S.; Hillhouse, Gregory L.

    2016-01-01

    The title compound, [Co2Na2{μ2-N(SiMe3)2}4](μ4-O), (I), represents a new entry in the class of inverse crown ethers. In the mol­ecule, each Co atom is formally in the oxidation state +II. The structure contains one half of a unique mol­ecule per asymmetric unit with the central μ4-oxido ligand residing on an inversion center, leading to a planar coordination to the Na and Co atoms. In the crystal, bulky tri­methyl­silyl substituents prevent additional inter­actions with cobalt. However, weak inter­molecular Na⋯H3C—Si inter­actions form an infinite chain along [010]. The structure is isotypic with its Mg, Mn and Zn analogues. PMID:27308041

  10. Crystal structure of the inverse crown ether tetra-kis-[μ2-bis-(tri-methyl-sil-yl)amido]-μ4-oxido-dicobalt(II)disodium, [Co2Na2{μ2-N(SiMe3)2}4](μ4-O).

    PubMed

    Hansen, Christopher B; Filatov, Alexander S; Hillhouse, Gregory L

    2016-06-01

    The title compound, [Co2Na2{μ2-N(SiMe3)2}4](μ4-O), (I), represents a new entry in the class of inverse crown ethers. In the mol-ecule, each Co atom is formally in the oxidation state +II. The structure contains one half of a unique mol-ecule per asymmetric unit with the central μ4-oxido ligand residing on an inversion center, leading to a planar coordination to the Na and Co atoms. In the crystal, bulky tri-methyl-silyl substituents prevent additional inter-actions with cobalt. However, weak inter-molecular Na⋯H3C-Si inter-actions form an infinite chain along [010]. The structure is isotypic with its Mg, Mn and Zn analogues. PMID:27308041

  11. {N,N′-Bis­[2-(di­phenyl­phosphan­yl)ethan-1-yl­idene]ethyl­enedi­amine}bromido­(p-toluene­sulfonyl­methyl isocyanide)iron(II) tetra­phenyl­borate

    PubMed Central

    Sues, Peter E.; Lough, Alan J.; Morris, Robert H.

    2014-01-01

    In the title compound, [FeBr(C9H9NO2S)(C30H30N2P2)][B(C6H5)4], the FeII ion is in a distorted octa­hedral CBrN2P2 coordination geometry with a P—Fe—P angle of 109.95 (3)°. The relative orientation of the p-toluene­sulfonyl­methyl isocyanide ligand is defined by the C—S—C—N torsion angle of 67.1 (2)°. In the crystal, pairs of weak C—H⋯O hydrogen bonds connect the cations into inversion dimers, forming R 2 2(8) rings. PMID:24826104

  12. The metal complexes of heterocyclic β-diketones and their derivatives—V. The synthesis, structure and i.r. spectral studies of metal(II) complexes of 1-phenyl-3-methyl-4-acetyl-pyrazolone-5 (HPMAP)

    NASA Astrophysics Data System (ADS)

    Okafor, Emmanuel Chukwuemeka

    The divalent metal complexes of Be, Mn, Co, Ni, Cu, Zn, Pb, Hg and Ba with 1-phenyl-3-methyl-4-acetyl-pyrazolone-5 (HPMAP), have been synthesized for the first time. It is shown that even though the ligand, HPMAP, has four potential coordination sites, it behaves like a bidentate enol forming neutral metal chelates through the carbonyl and enolic hydroxyl groups. The complexes were characterized by means of elemental analyses, conductivity measurements, i.r. proton NMR spectroscopy. Proton magnetic resonance spectral data for some of the chelates have been recorded and discussed. The i.r. spectra of HPMAP and its chelates have been measured between 4000 and 200 cm -1 and assignments are proposed for the observed frequencies. Replacement of a methyl group in the acetylacetonate by the pyrazolone moiety fused to the chelate ring has been found to strengthen the C …O and MO bonds and weaken the C …C bond of the chelate ring. The magnitudes of MO stretching frequencies for the transition metals follow very closely the Irving-Williams stability order Cu > Ni > Zn > Co > Mn.

  13. (Glycol-κ2 O,O′)nitros­yl(η5-penta­methyl­cyclo­penta­dien­yl)ruthenium(II) bis­(tri­fluoro­methane­sulfonate)

    PubMed Central

    Munie, Semeret; Larsen, Anna; Gembicky, Milan

    2008-01-01

    The title compound, [Ru(C10H15)(NO)(HOCH2CH2OH)](CF3SO3)2, possesses a three-legged piano-stool geometry around the Ru atom, with an average Ru—O distance of 2.120 (6) Å and an Ru—N—O angle of 159.45 (14)°. The ethyl­eneglycol ligand forms a non-planar metallacyclic ring by chelating the Ru atom via the O atoms. The O⋯O distances of 2.554 (2) and 2.568 (2) Å are indicative of hydrogen bonding between coordinated ethyl­eneglycol and outer-sphere trifluoro­methane­sulfonate fragments. The crystal packing is stabilized by ionic forces and several CH3⋯·F (2.585 and 2.640 Å) and CH3⋯O inter­actions (2.391, 2.678, 2.694 and 2.699 Å) between the penta­methyl­cyclo­penta­dienyl ligand and trifluoro­methane­sulfonate anion. There is noticeable short inter­molecular contact [2.9039 (16) Å], between an O atom of the SO3 group and a C atom of the penta­methyl­cyclo­penta­dienyl ligand. PMID:21201270

  14. Pyroprocessing of oxidized sodium-bonded fast reactor fuel - An experimental study of treatment options for degraded EBR-II fuel

    SciTech Connect

    Hermann, S.D.; Gese, N.J.; Wurth, L.A.

    2013-07-01

    An experimental study was conducted to assess pyrochemical treatment options for degraded EBR-II fuel. As oxidized material, the degraded fuel would need to be converted back to metal to enable electrorefining within an existing electro-metallurgical treatment process. A lithium-based electrolytic reduction process was studied to assess the efficacy of converting oxide materials to metal with a particular focus on the impact of zirconium oxide and sodium oxide on this process. Bench-scale electrolytic reduction experiments were performed in LiCl-Li{sub 2}O at 650 C. degrees with combinations of manganese oxide (used as a surrogate for uranium oxide), zirconium oxide, and sodium oxide. In the absence of zirconium or sodium oxide, the electrolytic reduction of MnO showed nearly complete conversion to metal. The electrolytic reduction of a blend of MnO-ZrO{sub 2} in LiCl - 1 wt% Li{sub 2}O showed substantial reduction of manganese, but only 8.5% of the zirconium was found in the metal phase. The electrolytic reduction of the same blend of MnO-ZrO{sub 2} in LiCl - 1 wt% Li{sub 2}O - 6.2 wt% Na{sub 2}O showed substantial reduction of manganese, but zirconium reduction was even less at 2.4%. This study concluded that ZrO{sub 2} cannot be substantially reduced to metal in an electrolytic reduction system with LiCl - 1 wt% Li{sub 2}O at 650 C. degrees due to the perceived preferential formation of lithium zirconate. This study also identified a possible interference that sodium oxide may have on the same system by introducing a parasitic and cyclic reaction of dissolved sodium metal between oxidation at the anode and reduction at the cathode. When applied to oxidized sodium-bonded EBR-II fuel (e.g., U-10Zr), the prescribed electrolytic reduction system would not be expected to substantially reduce zirconium oxide, and the accumulation of sodium in the electrolyte could interfere with the reduction of uranium oxide, or at least render it less efficient.

  15. Experimental and Computational Studies of the Macrocyclic Effect of an Auxiliary Ligand on Electron and Proton Transfers Within Ternary Copper(II)–Histidine Complexes

    SciTech Connect

    Song, Tao; Lam, Corey; Ng, Dominic C.; Orlova, G.; Laskin, Julia; Fang, De-Cai; Chu, Ivan K.

    2009-06-01

    The dissociation of [CuII(L)His]•2+ complexes [L = diethylenetriamine (dien) or 1,4,7-triazacyclononane (9-aneN3)] bears a strong resemblance to the previously reported behavior of [CuII(L)GGH]•2+ complexes. We have used low energy collision-induced dissociation experiments and density functional theory (DFT) calculations at the B3LYP/6-31+G(d) level to study the macrocyclic effect of the auxiliary ligands on the formation of His•+ from prototypical [CuII(L)His]•2+ systems. DFT revealed that the relative energy barriers of the same electron transfer (ET) dissociation pathways of [CuII(9-aneN3)His]•2+ and [CuII(dien)His]•2+ are very similar, with the ET reactions of [CuII(9-aneN3)His]•2+ leading to the generation of two distinct His•+ species; in contrast, the proton transfer (PT) dissociation pathways of [CuII(9-aneN3)His]•2+ and [CuII(dien)His]•2+ differ considerably. The PT reactions of [CuII(9-aneN3)His]•2+ are associated with substantially higher barriers (>13 kcal/mol) than those of [CuII(dien)His]•2+. Thus, the sterically encumbered auxiliary 9-aneN3 ligand facilitates ET reactions while moderating PT reactions, allowing the formation of hitherto non-observable histidine radical cations.

  16. Experimental and theoretical proton affinities of methionine, methionine sulfoxide and their N- and C-terminal derivatives

    NASA Astrophysics Data System (ADS)

    Lioe, Hadi; O'Hair, Richard A. J.; Gronert, Scott; Austin, Allen; Reid, Gavin E.

    2007-11-01

    The proton affinities of methionine, methionine sulfoxide and their derivatives (methionine methyl ester, methionine sulfoxide methyl ester, methionine methyl amide, methionine sulfoxide methyl amide, N-acetyl methionine, N-acetyl methionine sulfoxide, N-acetyl methionine methyl ester, N-acetyl methionine sulfoxide methyl ester, N-acetyl methionine methyl amide and N-acetyl methionine sulfoxide methyl amide) were experimentally determined using the kinetic method, in which proton bound dimers formed via electrospray ionization (ESI) were subjected to collision induced dissociation (CID) in a triple quadrupole mass spectrometer. In addition, theoretical calculations carried out at the MP2/6-311 + G(2d,p)//B3LYP/6-31 + G(d,p) level of theory to determine the global minima of the neutral and protonated species of all derivatives studied, were used to predict theoretical proton affinities. The density function theory calculations not only support the experimental proton affinities, but also provide structural insights into the types of hydrogen bonding that stabilize the neutral and protonated methionine or methionine sulfoxide derivatives. Comparison of the proton affinities of the various methionine and methionine sulfoxide derivatives reveals that: (i) oxidation of methionine derivatives to methionine sulfoxide derivatives results in an increase in proton affinity due to higher intrinsic proton affinity and an increase in the ring size formed through charge complexation of the sulfoxide group, which allows more efficient hydrogen bonding compared to the sulfide group; (ii) C-terminal modification by methyl esterification or methyl amidation increases the proton affinity in the order of methyl amide > methyl ester > carboxylic acid due to improved charge stabilization; (iii) N-terminal modification by N-acetylation decreases proton affinity of the derivatives due to lower intrinsic proton affinity of the N-acetyl group as well as due to stabilization of the attached

  17. Methylation index as means of quantification of the compliance of sedimentary mercury to be methylated.

    PubMed

    Bełdowski, Jacek; Miotk, Michał; Pempkowiak, Janusz

    2015-08-01

    Methylmercury (MeHg) is the most bioavailable and toxic mercury species in the marine environment. MeHg concentration levels, methylation rates leading to MeHg formation, and methylation index (MI) are all used to assess the compliance of mercury to be methylated in the marine sedimentary environment. This paper reports on the works conducted on the MI upgrade. This paper proposes a new formula for calculating MI. Apart from labile mercury(II) and organic matter, it includes redox potential and abundance of sulfur-reducing bacteria (SRB), both essential factors for MeHg generation. The obtained MI is validated against actual sedimentary MeHg concentrations proving the potential usefulness of MI as a factor characterizing status of sedimentary environment regarding possible occurrence of MeHg. Moreover, values of the methylation index in particular regions show that MI values correspond well to environmental conditions in those areas. The values calculated correlate well with MeHg concentrations; however, the correlation coefficients vary between different regions. This has been attributed to the lack of empirical coefficients. Thus, MI could be used as a characteristic of the sedimentary environment indicating the potential presence of MeHg. It could also be used in methylation rate modeling, provided that empirical constants are applied to improve model performance. PMID:26160740

  18. Metabolic production of methylated selenium species requires adequate methylation status

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Obesity negatively impacts methylation status and markers of methylation status vary according to selenium status in supplemented subjects. We have proposed that disruptions in methylation capacity induced by obesity compromise demonstrable anti-cancer effects of Se supplementation. In order to addr...

  19. Different regulation of miR-29a-3p in glomeruli and tubules in an experimental model of angiotensin II-dependent hypertension: potential role in renal fibrosis.

    PubMed

    Castoldi, Giovanna; di Gioia, Cira; Giollo, Fabrizio; Carletti, Raffaella; Bombardi, Camila; Antoniotti, Marco; Roma, Francesca; Zerbini, Gianpaolo; Stella, Andrea

    2016-03-01

    The aim of this study was to evaluate the role of the angiotensin II (Ang II) induced-differential miRNA expression in renal glomerular and tubulo-interstitial fibrosis in an experimental model of Ang II-dependent hypertension. To clarify this issue, Sprague Dawley rats were treated with Ang II (200 ng/kg per minute, n = 15) or physiological saline (n = 14) for 4 weeks. Systolic blood pressure and albuminuria were measured every 2 weeks. At the end of the experimental period, renal glomerular and tubulo-interstitial fibrosis was evaluated by histomorphometric analysis, after Sirius-Red and Masson's trichrome staining. Ang II increased systolic blood pressure (P < 0.0001), albuminuria (P < 0.01) and both glomerular and tubulo-interstitial fibrosis (P < 0.01). Using laser capture microdissection and miRNA microarray analysis this study showed that miR-29a-3p was down-regulated in renal tubules and up-regulated in glomeruli. Real-time polymerase chain reaction (PCR) experiments confirmed in Ang II-treated rats a down-regulation of miR-29a-3p in tubules (P < 0.01), while no significant changes were observed in glomeruli. Matrix metalloproteinase-2 (MMP-2) was identified as putative miR-29a-3p target (by TargetScan, miRanda, Tarbase software) and functionally confirmed by luciferase activity assay. These data demonstrate that the effects of Ang II on miR-29a-3p expression in renal tubules is different from the one exerted in the glomeruli and that miR-29a-3p targets MMP-2. These results suggest that the development of renal fibrosis at glomerular and tubulo-interstitial level depends on different molecular mechanisms. PMID:26700017

  20. DNA Methylation in Osteoarthritis

    PubMed Central

    den Hollander, Wouter; Meulenbelt, Ingrid

    2015-01-01

    Osteoarthritis (OA) is a prevalent disease of articular joints and primarily characterized by degradation and calcification of articular cartilage. Presently, no effective treatment other than pain relief exists and patients ultimately need to undergo replacement surgery of the affected joint. During disease progression articular chondrocytes, the single cell type present in articular cartilage, show altered transcriptional profiles and undergo phenotypic changes that resemble the terminal differentiation route apparent in growth plate chondrocytes. Hence, given its prominent function in both regulating gene expression and maintaining cellular phenotypes, DNA methylation of CpG dinucleotides is intensively studied in the context of OA. An increasing number of studies have been published that employed a targeted approach on genes known to play a role in OA pathophysiology. As of such, it has become clear that OA responsive DNA methylation changes seem to mediate disease associated aberrant gene expression. Furthermore, established OA susceptibility alleles such as GDF5 and DIO2 appear to confer OA risk via DNA methylation and respective pathophysiological expression changes. In more recent years, genome wide profiling of DNA methylation in OA affected articular cartilage has emerged as a powerful tool to address the epigenetic changes in their entirety, which has resulted in the identification of putative patient subgroups as well as generic OA associated pathways. PMID:27019616

  1. DNA Methylation in Osteoarthritis.

    PubMed

    den Hollander, Wouter; Meulenbelt, Ingrid

    2015-12-01

    Osteoarthritis (OA) is a prevalent disease of articular joints and primarily characterized by degradation and calcification of articular cartilage. Presently, no effective treatment other than pain relief exists and patients ultimately need to undergo replacement surgery of the affected joint. During disease progression articular chondrocytes, the single cell type present in articular cartilage, show altered transcriptional profiles and undergo phenotypic changes that resemble the terminal differentiation route apparent in growth plate chondrocytes. Hence, given its prominent function in both regulating gene expression and maintaining cellular phenotypes, DNA methylation of CpG dinucleotides is intensively studied in the context of OA. An increasing number of studies have been published that employed a targeted approach on genes known to play a role in OA pathophysiology. As of such, it has become clear that OA responsive DNA methylation changes seem to mediate disease associated aberrant gene expression. Furthermore, established OA susceptibility alleles such as GDF5 and DIO2 appear to confer OA risk via DNA methylation and respective pathophysiological expression changes. In more recent years, genome wide profiling of DNA methylation in OA affected articular cartilage has emerged as a powerful tool to address the epigenetic changes in their entirety, which has resulted in the identification of putative patient subgroups as well as generic OA associated pathways. PMID:27019616

  2. Nutrients and DNA Methylation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Epigenetics is a new mechanism responsible for development, aging, and disease process such as cancer development. One major epigenetic phenomenon is DNA methylation, which attributes to gene expression and integrity. Deepening the knowledge on one-carbon metabolism is very important to understandin...

  3. Methyl Bromide Poisoning

    PubMed Central

    Rathus, E. M.; Landy, P. J.

    1961-01-01

    Seven cases of methyl bromide poisoning which occurred amongst workers engaged on a fumigation project are described. The methods adopted for investigation of the environmental situation are discussed and the measurement of blood bromide levels on random samples of workers is suggested as an index of the effectiveness of equipment and working methods. PMID:13739738

  4. Thiophanate-methyl

    Integrated Risk Information System (IRIS)

    Thiophanate - methyl ; CASRN 23564 - 05 - 8 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcino

  5. Pirimiphos-methyl

    Integrated Risk Information System (IRIS)

    Pirimiphos - methyl ; CASRN 29232 - 93 - 7 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinog

  6. Methyl isobutyl ketone (MIBK)

    Integrated Risk Information System (IRIS)

    Methyl Isobutyl Ketone ( MIBK ) ; CASRN 108 - 10 - 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

  7. Haloxyfop-methyl

    Integrated Risk Information System (IRIS)

    Haloxyfop - methyl ; CASRN 69806 - 40 - 2 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinoge

  8. Methyl ethyl ketone (MEK)

    Integrated Risk Information System (IRIS)

    Methyl ethyl ketone ( MEK ) ( CASRN 78 - 93 - 3 ) Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Nonc

  9. Chloromethyl methyl ether (CMME)

    Integrated Risk Information System (IRIS)

    Chloromethyl methyl ether ( CMME ) ; CASRN 107 - 30 - 2 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments fo

  10. Kenaf methyl esters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Additional or alternative feedstocks are one of the major areas of interest regarding biodiesel. In this paper, for the first time, the fuel properties of kenaf (Hibiscus cannabinus L.) seed oil methyl esters are comprehensively reported. This biodiesel is also relatively unique by containing small ...

  11. Kapok oil methyl esters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The increased need for biodiesel feedstocks has caused various vegetable oils to be examined for this purpose. In the present work, the methyl esters of kapok (Ceiba pentandra) oil were prepared. The essential fuel properties were comprehensively determined and evaluated in comparison to specificati...

  12. Protective vaccination against experimental canine visceral leishmaniasis using a combination of DNA and protein immunization with cysteine proteinases type I and II of L. infantum.

    PubMed

    Rafati, Sima; Nakhaee, Alireza; Taheri, Tahere; Taslimi, Yasaman; Darabi, Haideh; Eravani, Davood; Sanos, Stephanie; Kaye, Paul; Taghikhani, Mohammad; Jamshidi, Shahram; Rad, Mohammad Ali

    2005-05-25

    Leishmania infantum is known to be associated with visceral leishmaniasis in Iran and canids are natural reservoirs. Control of disease in dogs appears to be one of the most effective approaches for interrupting the domestic cycle of the disease. In search for successful vaccine strategies, we evaluated the cysteine proteinases (CPs) type I and II using a heterologous prime-boost regime for vaccination against experimental visceral leishmaniasis in dogs. Following vaccination and challenge, dogs were followed for 12 months. Ten dogs vaccinated by prime/boost with DNA/recombinant CPs (in combination with CpG ODN and Montanide 720) remained free of infection in their bone morrow. In contrast, three out of four dogs in the control groups had infection in their bone marrow. The peripheral lymphocytes from protected animals had generally higher proliferation responses to F/T antigen, recombinant CPA (rCPA) and recombinant CPB (rCPB) than controls. During post-challenge period, the difference in stimulation index is significant (p<0.05) on months 11 and 12 to F/T antigens, all months for rCPA and 5, 7, 9, 11 and 12 months for rCPB. Analysis of cytokine mRNA level suggested that vaccinated dogs had elevated IFN-gamma mRNA in peripheral blood mononuclear cells (PBMC), whereas there was a consistent increase in the level of IL-10 in the control groups and some vaccinated dogs. The level of total IgG and IgG2, but not IgG1, to rCPA and rCPB was significantly higher in the vaccinated group (p<0.05) than the control groups. We also showed that with the exception of one dog, all dogs in the vaccinated group in comparison to control dogs had strong DTH responses. We propose that the combination of DNA and recombinant protein vaccination using CPs could be instrumental to control (VL) in dogs. PMID:15882533

  13. 21 CFR 177.1030 - Acrylonitrile/butadiene/styrene/methyl methacrylate copolymer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    .../styrene/methyl methacrylate copolymer consists of: (1) 73 to 79 parts by weight of a matrix polymer... weight of methyl methacrylate; and (2) 21 to 27 parts by weight of a grafted rubber consisting of (i) 16... 28 parts by weight of styrene and (ii) 5 to 10 parts by weight of a graft polymer having the...

  14. 21 CFR 177.1030 - Acrylonitrile/butadiene/styrene/methyl methacrylate copolymer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    .../styrene/methyl methacrylate copolymer consists of: (1) 73 to 79 parts by weight of a matrix polymer... weight of methyl methacrylate; and (2) 21 to 27 parts by weight of a grafted rubber consisting of (i) 16... 28 parts by weight of styrene and (ii) 5 to 10 parts by weight of a graft polymer having the...

  15. 21 CFR 177.1030 - Acrylonitrile/butadiene/styrene/methyl methacrylate copolymer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    .../styrene/methyl methacrylate copolymer consists of: (1) 73 to 79 parts by weight of a matrix polymer... weight of methyl methacrylate; and (2) 21 to 27 parts by weight of a grafted rubber consisting of (i) 16... 28 parts by weight of styrene and (ii) 5 to 10 parts by weight of a graft polymer having the...

  16. Statistical Quantification of Methylation Levels by Next-Generation Sequencing

    PubMed Central

    Wu, Guodong; Yi, Nengjun; Absher, Devin; Zhi, Degui

    2011-01-01

    Background/Aims Recently, next-generation sequencing-based technologies have enabled DNA methylation profiling at high resolution and low cost. Methyl-Seq and Reduced Representation Bisulfite Sequencing (RRBS) are two such technologies that interrogate methylation levels at CpG sites throughout the entire human genome. With rapid reduction of sequencing costs, these technologies will enable epigenotyping of large cohorts for phenotypic association studies. Existing quantification methods for sequencing-based methylation profiling are simplistic and do not deal with the noise due to the random sampling nature of sequencing and various experimental artifacts. Therefore, there is a need to investigate the statistical issues related to the quantification of methylation levels for these emerging technologies, with the goal of developing an accurate quantification method. Methods In this paper, we propose two methods for Methyl-Seq quantification. The first method, the Maximum Likelihood estimate, is both conceptually intuitive and computationally simple. However, this estimate is biased at extreme methylation levels and does not provide variance estimation. The second method, based on Bayesian hierarchical model, allows variance estimation of methylation levels, and provides a flexible framework to adjust technical bias in the sequencing process. Results We compare the previously proposed binary method, the Maximum Likelihood (ML) method, and the Bayesian method. In both simulation and real data analysis of Methyl-Seq data, the Bayesian method offers the most accurate quantification. The ML method is slightly less accurate than the Bayesian method. But both our proposed methods outperform the original binary method in Methyl-Seq. In addition, we applied these quantification methods to simulation data and show that, with sequencing depth above 40–300 (which varies with different tissue samples) per cleavage site, Methyl-Seq offers a comparable quantification

  17. Chlorido[2-({[2-(diphenyl­phosphan­yl)­benzyl­idene]amino}­meth­yl)thio­phene-κ2 N,P]methyl­palladium(II)

    PubMed Central

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

    2012-01-01

    In the title compound, [Pd(CH3)Cl(C24H20NPS)], the PdII ion is coordinated in a distorted square-planar environment which includes the P and N atoms of the bis-chelating ligand. The thio­phene ring is rotationally ordered, unlike in the majority of crystal structures containing this group. PMID:22412470

  18. Novel features of telomere biology revealed by the absence of telomeric DNA methylation.

    PubMed

    Vega-Vaquero, Alejandro; Bonora, Giancarlo; Morselli, Marco; Vaquero-Sedas, María I; Rubbi, Liudmilla; Pellegrini, Matteo; Vega-Palas, Miguel A

    2016-08-01

    Cytosine methylation regulates the length and stability of telomeres, which can affect a wide variety of biological features, including cell differentiation, development, or illness. Although it is well established that subtelomeric regions are methylated, the presence of methylated cytosines at telomeres has remained controversial. Here, we have analyzed multiple bisulfite sequencing studies to address the methylation status of Arabidopsis thaliana telomeres. We found that the levels of estimated telomeric DNA methylation varied among studies. Interestingly, we estimated higher levels of telomeric DNA methylation in studies that produced C-rich telomeric strands with lower efficiency. However, these high methylation estimates arose due to experimental limitations of the bisulfite technique. We found a similar phenomenon for mitochondrial DNA: The levels of mitochondrial DNA methylation detected were higher in experiments with lower mitochondrial read production efficiencies. Based on experiments with high telomeric C-rich strand production efficiencies, we concluded that Arabidopsis telomeres are not methylated, which was confirmed by methylation-dependent restriction enzyme analyses. Thus, our studies indicate that telomeres are refractory to de novo DNA methylation by the RNA-directed DNA methylation machinery. This result, together with previously reported data, reveals that subtelomeric DNA methylation controls the homeostasis of telomere length. PMID:27405804

  19. Engineering of Bacterial Methyl Ketone Synthesis for Biofuels

    PubMed Central

    Goh, Ee-Been; Baidoo, Edward E. K.; Keasling, Jay D.

    2012-01-01

    We have engineered Escherichia coli to overproduce saturated and monounsaturated aliphatic methyl ketones in the C11 to C15 (diesel) range; this group of methyl ketones includes 2-undecanone and 2-tridecanone, which are of importance to the flavor and fragrance industry and also have favorable cetane numbers (as we report here). We describe specific improvements that resulted in a 700-fold enhancement in methyl ketone titer relative to that of a fatty acid-overproducing E. coli strain, including the following: (i) overproduction of β-ketoacyl coenzyme A (CoA) thioesters achieved by modification of the β-oxidation pathway (specifically, overexpression of a heterologous acyl-CoA oxidase and native FadB and chromosomal deletion of fadA) and (ii) overexpression of a native thioesterase (FadM). FadM was previously associated with oleic acid degradation, not methyl ketone synthesis, but outperformed a recently identified methyl ketone synthase (Solanum habrochaites MKS2 [ShMKS2], a thioesterase from wild tomato) in β-ketoacyl-CoA-overproducing strains tested. Whole-genome transcriptional (microarray) studies led to the discovery that FadM is a valuable catalyst for enhancing methyl ketone production. The use of a two-phase system with decane enhanced methyl ketone production by 4- to 7-fold in addition to increases from genetic modifications. PMID:22038610

  20. PTEN methylation involved in benzene-induced hematotoxicity.

    PubMed

    Yang, Jing; Zuo, Xin; Bai, Wenlin; Niu, Piye; Tian, Lin; Gao, Ai

    2014-06-01

    It is well known that benzene is a hematotoxic carcinogen. PTEN promoter methylation is a representative example of transcriptional silencing of tumor suppressor genes. However, the effect of PTEN methylation on benzene-induced hematotoxicity has not yet been elucidated. In this study, the animal model of benzene hematotoxicity was successfully established. WBC significantly decreased in experimental groups (P < 0.01). Compared with the control group, the weight of rats increased slowly and even declined with increasing doses of benzene in the benzene-treated groups. An increase in the level of PTEN methylation was observed in the low dose group, and PTEN methylation level increased significantly in a dose-dependent manner. However, it was interesting that PTEN mRNA expression increased in the low dose group, but declined with increasing doses of benzene. The decrease of tumor suppressor function caused by PTEN methylation may be an important mechanism of benzene hematotoxicity. Furthermore, lymphoblast cell line F32 was incubated by benzene and then treated with 5-aza and TSA, alone or in combination. A dramatic decrease in the PTEN mRNA expression and a significant increase of PTEN methylation level in benzene-treated cells were also shown. PTEN mRNA expression was up regulated and PTEN methylation level was reduced by the epigenetic inhibitors, 5-aza and TSA. In conclusion, PTEN methylation is involved in benzene-induced hematotoxicity through suppressing PTEN mRNA expression. PMID:24680972