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Sample records for complex lhca4 mixing

  1. Excitation Energy Transfer Pathways in Lhca4

    PubMed Central

    Gibasiewicz, K.; Croce, R.; Morosinotto, T.; Ihalainen, J. A.; van Stokkum, I. H. M.; Dekker, J. P.; Bassi, R.; van Grondelle, R.

    2005-01-01

    EET in reconstituted Lhca4, a peripheral light-harvesting complex from Photosystem I of Arabidopsis thaliana, containing 10 chlorophylls and 2 carotenoids, was studied at room temperature by femtosecond transient absorption spectroscopy. Two spectral forms of Lut were observed in the sites L1 and L2, characterized by significantly different interactions with nearby chlorophyll a molecules. A favorable interpretation of these differences is that the efficiency of EET to Chls is about two times lower from the “blue” Lut in the site L1 than from the “red” Lut in the site L2 due to fast IC in the former case. A major part of the energy absorbed by the “red” Lut, ∼60%–70%, is transferred to Chls on a sub-100-fs timescale from the state S2 but, in addition, minor EET from the hot S1 state within 400–500 fs is also observed. EET from the S1 state to chlorophylls occurs also within 2–3 ps and is ascribed to Vio and/or “blue” Lut. EET from Chl b to Chl a is biphasic and characterized by time constants of ∼300 fs and 3.0 ps. These rates are ascribed to EET from Chl b spectral forms absorbing at ∼644 nm and ∼650 nm, respectively. About 25% of the excited Chls a decays very fast—within ∼15 ps. This decay is proposed to be related to the presence of the interacting Chls A5 and B5 located next to the carotenoid in the site L2 and may imply some photoprotective role for Lhca4 in the photosystem I super-complex. PMID:15653744

  2. The low-energy forms of photosystem I light-harvesting complexes: spectroscopic properties and pigment-pigment interaction characteristics.

    PubMed

    Croce, Roberta; Chojnicka, Agnieszka; Morosinotto, Tomas; Ihalainen, Janne A; van Mourik, Frank; Dekker, Jan P; Bassi, Roberto; van Grondelle, Rienk

    2007-10-01

    In this work the spectroscopic properties of the special low-energy absorption bands of the outer antenna complexes of higher plant Photosystem I have been investigated by means of low-temperature absorption, fluorescence, and fluorescence line-narrowing experiments. It was found that the red-most absorption bands of Lhca3, Lhca4, and Lhca1-4 peak, respectively, at 704, 708, and 709 nm and are responsible for 725-, 733-, and 732-nm fluorescence emission bands. These bands are more red shifted compared to "normal" chlorophyll a (Chl a) bands present in light-harvesting complexes. The low-energy forms are characterized by a very large bandwidth (400-450 cm(-1)), which is the result of both large homogeneous and inhomogeneous broadening. The observed optical reorganization energy is untypical for Chl a and resembles more that of BChl a antenna systems. The large broadening and the changes in optical reorganization energy are explained by a mixing of an Lhca excitonic state with a charge transfer state. Such a charge transfer state can be stabilized by the polar residues around Chl 1025. It is shown that the optical reorganization energy is changing through the inhomogeneous distribution of the red-most absorption band, with the pigments contributing to the red part of the distribution showing higher values. A second red emission form in Lhca4 was detected at 705 nm and originates from a broad absorption band peaking at 690 nm. This fluorescence emission is present also in the Lhca4-N-47H mutant, which lacks the 733-nm emission band.

  3. Mixed real/complex factorization

    SciTech Connect

    Lima, L.T.G. . Dept. of Electrical Engineering); Martines, N.; Pinto, H.J.C.P. . Centro de Pesquisas de Energia Electrica)

    1993-02-01

    This paper describes a mixed real/complex sparse matrix factorization and solution scheme applied to a large matrix problem. Large system eigenanalysis and frequency domain methods will directly benefit from the proposed scheme, which can reduce both memory and CPU time requirements when compared to conventional complex-only solutions. The application in hand is the small signal electromechanical stability analysis of large power systems. The savings obtained are significant considering the CPU intensive nature of these matrix problems.

  4. 40 CFR 721.10104 - Halophosphate mixed metal complex (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Halophosphate mixed metal complex... Specific Chemical Substances § 721.10104 Halophosphate mixed metal complex (generic). (a) Chemical... as halophosphate mixed metal complex (PMN P-04-254) is subject to reporting under this section...

  5. 40 CFR 721.10104 - Halophosphate mixed metal complex (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Halophosphate mixed metal complex... Specific Chemical Substances § 721.10104 Halophosphate mixed metal complex (generic). (a) Chemical... as halophosphate mixed metal complex (PMN P-04-254) is subject to reporting under this section...

  6. 40 CFR 721.10104 - Halophosphate mixed metal complex (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Halophosphate mixed metal complex... Specific Chemical Substances § 721.10104 Halophosphate mixed metal complex (generic). (a) Chemical... as halophosphate mixed metal complex (PMN P-04-254) is subject to reporting under this section...

  7. 40 CFR 721.10104 - Halophosphate mixed metal complex (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Halophosphate mixed metal complex... Specific Chemical Substances § 721.10104 Halophosphate mixed metal complex (generic). (a) Chemical... as halophosphate mixed metal complex (PMN P-04-254) is subject to reporting under this section...

  8. 40 CFR 721.10104 - Halophosphate mixed metal complex (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Halophosphate mixed metal complex... Specific Chemical Substances § 721.10104 Halophosphate mixed metal complex (generic). (a) Chemical... as halophosphate mixed metal complex (PMN P-04-254) is subject to reporting under this section...

  9. What is mixing and can it be complex?

    NASA Astrophysics Data System (ADS)

    Klimenko, A. Y.

    2013-07-01

    While the concept of mixing is commonly used in science and engineering, its exact interpretation may vary between different disciplines. In the present work, we analyse the concept of mixing in context of mechanical mixing, the ergodic theory, modelling of turbulent reacting fluid flows and complex competitive systems. Although mixing represents a dissipative process, which is responsible for irreversible increase of molecular disorder, mixing nevertheless can be associated with emergence of complexity under certain conditions. This dual role of mixing is noted and examined here. The appendix discusses three fundamental hypotheses, which are related to understanding of mixing and were introduced by Boltzmann.

  10. Mixing and Processing of Complex Biological Fluids

    DTIC Science & Technology

    2003-03-01

    Microfabricated Microneedles ," Technical Proceedings of the 2002 International Conference on Computational Nanoscienceand Nanotechnology, and Technical...France, 12-14 Oct. 2000, 311-15. Zahn, J.D. and Liepmann, D. (2000) "Complex Biological Fluid Flow Through Microfabricated Microneedles ," Proceedings

  11. Active mixing of complex fluids at the microscale

    SciTech Connect

    Ober, Thomas J.; Foresti, Daniele; Lewis, Jennifer A.

    2015-09-22

    Mixing of complex fluids at low Reynolds number is fundamental for a broad range of applications, including materials assembly, microfluidics, and biomedical devices. Of these materials, yield stress fluids (and gels) pose the most significant challenges, especially when they must be mixed in low volumes over short timescales. New scaling relationships between mixer dimensions and operating conditions are derived and experimentally verified to create a framework for designing active microfluidic mixers that can efficiently homogenize a wide range of complex fluids. As a result, active mixing printheads are then designed and implemented for multimaterial 3D printing of viscoelastic inks with programmable control of local composition.

  12. Active mixing of complex fluids at the microscale

    PubMed Central

    Ober, Thomas J.; Foresti, Daniele; Lewis, Jennifer A.

    2015-01-01

    Mixing of complex fluids at low Reynolds number is fundamental for a broad range of applications, including materials assembly, microfluidics, and biomedical devices. Of these materials, yield stress fluids (and gels) pose the most significant challenges, especially when they must be mixed in low volumes over short timescales. New scaling relationships between mixer dimensions and operating conditions are derived and experimentally verified to create a framework for designing active microfluidic mixers that can efficiently homogenize a wide range of complex fluids. Active mixing printheads are then designed and implemented for multimaterial 3D printing of viscoelastic inks with programmable control of local composition. PMID:26396254

  13. Active mixing of complex fluids at the microscale

    DOE PAGES

    Ober, Thomas J.; Foresti, Daniele; Lewis, Jennifer A.

    2015-09-22

    Mixing of complex fluids at low Reynolds number is fundamental for a broad range of applications, including materials assembly, microfluidics, and biomedical devices. Of these materials, yield stress fluids (and gels) pose the most significant challenges, especially when they must be mixed in low volumes over short timescales. New scaling relationships between mixer dimensions and operating conditions are derived and experimentally verified to create a framework for designing active microfluidic mixers that can efficiently homogenize a wide range of complex fluids. As a result, active mixing printheads are then designed and implemented for multimaterial 3D printing of viscoelastic inks withmore » programmable control of local composition.« less

  14. Mixed and Complex Mixed Migration during Armed Conflict: Multidimensional Empirical Evidence from Nepal.

    PubMed

    Williams, Nathalie E

    Historically, legal, policy, and academic communities largely ascribed to a dichotomy between forced and voluntary migration, creating a black and white vision that was convenient for legal and policy purposes. More recently, discussions have begun addressing the possibility of mixed migration, acknowledging that there is likely a wide continuum between forced and voluntary, and most migrants likely move with some amount of compulsion and some volition, even during armed conflict. While the mixed migration hypothesis is well-received, empirical evidence is disparate and somewhat blunt at this point. In this article, I contribute a direct theoretical and causal pathway discussion of mixed migration. I also propose the complex mixed migration hypothesis, which argues that not only do non-conflict related factors influence migration during conflict, but they do so differently than during periods of relative peace. I empirically test both hypotheses in the context of the recent armed conflict in Nepal. Using detailed survey data and event history models, results provide strong evidence for both mixed migration and complex mixed migration during conflict hypotheses. These hypotheses and evidence suggest that armed conflict might have substantial impacts on long-term population growth and change, with significant relevance in both academic and policy spheres.

  15. Mixed and Complex Mixed Migration during Armed Conflict: Multidimensional Empirical Evidence from Nepal

    PubMed Central

    Williams, Nathalie E.

    2015-01-01

    Historically, legal, policy, and academic communities largely ascribed to a dichotomy between forced and voluntary migration, creating a black and white vision that was convenient for legal and policy purposes. More recently, discussions have begun addressing the possibility of mixed migration, acknowledging that there is likely a wide continuum between forced and voluntary, and most migrants likely move with some amount of compulsion and some volition, even during armed conflict. While the mixed migration hypothesis is well-received, empirical evidence is disparate and somewhat blunt at this point. In this article, I contribute a direct theoretical and causal pathway discussion of mixed migration. I also propose the complex mixed migration hypothesis, which argues that not only do non-conflict related factors influence migration during conflict, but they do so differently than during periods of relative peace. I empirically test both hypotheses in the context of the recent armed conflict in Nepal. Using detailed survey data and event history models, results provide strong evidence for both mixed migration and complex mixed migration during conflict hypotheses. These hypotheses and evidence suggest that armed conflict might have substantial impacts on long-term population growth and change, with significant relevance in both academic and policy spheres. PMID:26366007

  16. Complex earthquake networks: Hierarchical organization and assortative mixing

    NASA Astrophysics Data System (ADS)

    Abe, Sumiyoshi; Suzuki, Norikazu

    2006-08-01

    To characterize the dynamical features of seismicity as a complex phenomenon, the seismic data are mapped to a growing random graph, which is a small-world scale-free network. Here, hierarchical and mixing properties of such a network are studied. The clustering coefficient is found to exhibit asymptotic power-law decay with respect to connectivity, showing hierarchical organization. This structure is supported by not only main shocks but also small shocks, and may have its origin in the combined effect of vertex fitness and deactivation by stress release at faults. The nearest-neighbor average connectivity and the Pearson correlation coefficient are also calculated. It is found that the earthquake network has assortative mixing. This is a main difference of the earthquake network from the Internet with disassortative mixing. Physical implications of these results are discussed.

  17. Multikernel linear mixed models for complex phenotype prediction

    PubMed Central

    Weissbrod, Omer; Geiger, Dan; Rosset, Saharon

    2016-01-01

    Linear mixed models (LMMs) and their extensions have recently become the method of choice in phenotype prediction for complex traits. However, LMM use to date has typically been limited by assuming simple genetic architectures. Here, we present multikernel linear mixed model (MKLMM), a predictive modeling framework that extends the standard LMM using multiple-kernel machine learning approaches. MKLMM can model genetic interactions and is particularly suitable for modeling complex local interactions between nearby variants. We additionally present MKLMM-Adapt, which automatically infers interaction types across multiple genomic regions. In an analysis of eight case-control data sets from the Wellcome Trust Case Control Consortium and more than a hundred mouse phenotypes, MKLMM-Adapt consistently outperforms competing methods in phenotype prediction. MKLMM is as computationally efficient as standard LMMs and does not require storage of genotypes, thus achieving state-of-the-art predictive power without compromising computational feasibility or genomic privacy. PMID:27302636

  18. Complexation-triggerable liposome mixed with silk protein and chitosan.

    PubMed

    Hong, Yeon-Ji; Kim, Jin-Chul

    2015-01-01

    Complexation-triggerable liposomes were prepared by modifying the surface of egg phosphatidylcholine (EPC) liposomes with hydrophobicized silk fibroin (HmSF) and hydrophobicized chitosan (HmCh). Maximum complexation, determined by measuring the diameter of complexation, was found when the ratio of HmSF to HmCh was 14:1, so they were immobilized on the surface of liposomes at the same ratio. The degree of fluorescence quenching of calcein in liposomal suspension was as high as 68% when the ratio of surface modifier (HmSF + HmCh) to EPC was 1:15. When the ratio was increased to 1:5, the degree of quenching decreased to 32%, indicating the inefficient formation of liposome. Liposome mixed with the surface modifier was multi-lamellar vesicle on TEM photo. And, the mean diameter was larger than those of liposome mixed with either HmSF or HmCh, possibly due to insoluble complex on the liposomal surface. The liposome exhibited a pH-sensitive release and triggered the release at pH 5.5 and 6.0. It is believed that complexation is responsible for the promoted release at those pH values.

  19. Using jet mixing to prepare polyelectrolyte complexes: complex properties and their interaction with silicon oxide surfaces.

    PubMed

    Ankerfors, Caroline; Ondaral, Sedat; Wågberg, Lars; Odberg, Lars

    2010-11-01

    The influence of mixing procedure on the properties of polyelectrolyte complexes (PECs) was investigated using two complexation techniques, polyelectrolyte titration and jet mixing, the latter being a new method for PEC preparation. For the low-molecular-weight polyelectrolytes polyacrylic acid (PAA) and polyallyl amine hydrochloride (PAH), shorter mixing times produced smaller PECs, whereas for higher molecular weights of the same polyelectrolytes, PEC size first decreased with decreasing mixing time to a certain level, after which it started increasing again. This pattern was likely due to the diffusion-controlled formation of "pre-complexes", which, in the case of low-molecular-weight polymers, occurs sufficiently quickly to form stable complexes; when polyelectrolytes are larger, however, non-equilibrium pre-complexes, more prone to aggregation, are formed. Comparing the techniques revealed that jet mixing produced smaller complexes, allowing PEC size to be controlled by mixing time, which was not the case with polyelectrolyte titration. Higher polyelectrolyte concentration during jet mixing led to the formation of larger PECs. It was also demonstrated that PEC size could be changed after preparation: increasing the pH of the PEC dispersion led to an irreversible increase in PEC size, whereas lowering the pH did not influence PEC size. The adsorption behavior of PECs formed from weak polyelectrolytes on model substrates was studied using QCM-D, SPAR, and AFM imaging; the results indicated that increasing the pH increased the amount of PECs adsorbed to model surfaces. However, the amount of PECs adsorbed to the model surfaces was low compared with other systems in all studied cases. Copyright 2010 Elsevier Inc. All rights reserved.

  20. Synthesis, spectroscopic, thermogravimetric and antimicrobial studies of mixed ligands complexes

    NASA Astrophysics Data System (ADS)

    Mahmoud, Walaa H.; Mahmoud, Nessma F.; Mohamed, Gehad G.; El-Sonbati, Adel Z.; El-Bindary, Ashraf A.

    2015-09-01

    An interesting series of mixed ligand complexes have been synthesized by the reaction of metal chloride with guaifenesin (GFS) in the presence of 2-aminoacetic acid (HGly) (1:1:1 molar ratio). The elemental analysis, magnetic moments, molar conductance, spectral (UV-Vis, IR, 1H NMR and ESR) and thermal studies were used to characterize the isolated complexes. The molecular structure of GFS is optimized theoretically and the quantum chemical parameters are calculated. The IR showed that the ligand (GFS) acts as monobasic tridentate through the hydroxyl, phenoxy etheric and methoxy oxygen atoms and co-ligand (HGly) as monobasic bidentate through the deprotonated carboxylate oxygen atom and nitrogen atom of amino group. The molar conductivities showed that all the complexes are non-electrolytes except Cr(III) complex is electrolyte. Electronic and magnetic data proposed the octahedral structure for all complexes under investigation. ESR spectrum for Cu(II) revealed data which confirm the proposed structure. Antibacterial screening of the compounds were carried out in vitro on gram positive (Bacillus subtilis and Staphylococcus aureus), gram negative (Escherichia coli and Neisseria gonorrhoeae) bacteria and for in vitro antifungal activity against Candida albicans organism. However, some complexes showed more chemotherapeutic efficiency than the parent GFS drug. The complexes were also screened for their in vitro anticancer activity against the breast cell line (MFC7) and the results obtained showed that they exhibit a considerable anticancer activity.

  1. Supramolecular coordination and antimicrobial activities of constructed mixed ligand complexes

    NASA Astrophysics Data System (ADS)

    El-Sonbati, A. Z.; Diab, M. A.; El-Bindary, A. A.; Abou-Dobara, M. I.; Seyam, H. A.

    2013-03-01

    A novel series of copper(II) and palladium(II) with 4-derivatives benzaldehyde pyrazolone (Ln) were synthesized. The mixed ligand complexes were prepared by using 1,10-phenanthroline (Phen) as second ligand. The structure of these complexes was identified and confirm by elemental analysis, molar conductivity, UV-Vis, IR and 1H NMR spectroscopy and magnetic moment measurements as well as thermal analysis. The ligand behaves as a neutral bidentate ligand through ON donor sites. ESR spectra show the simultaneous presence of a planar trans and a nearly planar cis isomers in the 1:2 ratio for all N,O complexes [Cu(Ln)2]Cl2ṡ2H2O. Schiff bases (Ln) were tested against bacterial species; namely two Gram positive bacteria (Staphylococcus aureus and Bacillus cereus) and two Gram negative bacteria (Escherichia coli and Klebsiella pneumoniae) and fungal species (Aspergillus niger, Fusarium oxysporium, Penicillium italicum and Alternaria alternata). The tested compounds have antibacterial activity against S. aureus, B. cereus and K. pneumoniae.

  2. Mixed Waste Focus Area: Department of Energy complex needs report

    SciTech Connect

    Roach, J.A.

    1995-11-16

    The Assistant Secretary for the Office of Environmental Management (EM) at the US Department of Energy (DOE) initiated a new approach in August of 1993 to environmental research and technology development. A key feature of this new approach included establishment of the Mixed Waste Characterization, Treatment, and Disposal Focus Area (MWFA). The mission of the MWFA is to identify, develop, and implement needed technologies such that the major environmental management problems related to meeting DOE`s commitments for treatment of mixed wastes under the Federal Facility Compliance Act (FFCA), and in accordance with the Land Disposal Restrictions (LDR) of the Resource Conservation and Recovery Act (RCRA), can be addressed, while cost-effectively expending the funding resources. To define the deficiencies or needs of the EM customers, the MWFA analyzed Proposed Site Treatment Plans (PSTPs), as well as other applicable documents, and conducted site visits throughout the summer of 1995. Representatives from the Office of Waste Management (EM-30), the Office of Environmental Restoration (EM-40), and the Office of Facility Transition and Management (EM-60) at each site visited were requested to consult with the Focus Area to collaboratively define their technology needs. This report documents the needs, deficiencies, technology gaps, and opportunities for expedited treatment activities that were identified during the site visit process. The defined deficiencies and needs are categorized by waste type, namely Wastewaters, Combustible Organics, Sludges/Soils, Debris/Solids, and Unique Wastes, and will be prioritized based on the relative affect the deficiency has on the DOE Complex.

  3. Finding community structures in complex networks using mixed integer optimisation

    NASA Astrophysics Data System (ADS)

    Xu, G.; Tsoka, S.; Papageorgiou, L. G.

    2007-11-01

    The detection of community structure has been used to reveal the relationships between individual objects and their groupings in networks. This paper presents a mathematical programming approach to identify the optimal community structures in complex networks based on the maximisation of a network modularity metric for partitioning a network into modules. The overall problem is formulated as a mixed integer quadratic programming (MIQP) model, which can then be solved to global optimality using standard optimisation software. The solution procedure is further enhanced by developing special symmetry-breaking constraints to eliminate equivalent solutions. It is shown that additional features such as minimum/maximum module size and balancing among modules can easily be incorporated in the model. The applicability of the proposed optimisation-based approach is demonstrated by four examples. Comparative results with other approaches from the literature show that the proposed methodology has superior performance while global optimum is guaranteed.

  4. PT L 3 near edge structure of halogen-bridged mixed-valence pt complexes and pd-pt mixed-metal complexes

    NASA Astrophysics Data System (ADS)

    Tanino, H.; Oyanagi, H.; Yamashita, M.; Kobayashi, K.

    1985-03-01

    X-ray absorption near edge structure (XANES) of halogen-bridged mixed-valence Pt complexes and halogen-bridged Pd-Pt mixed-metal complexes have been measured using synchrotron radiation with a high energy resolution. In Pd-Pt mixed metal complexes, we demonstrate that the degree of the valence is estimated from the intensity of the white line at the Pt L 3 edge. In the mixed-valence complexes, the electron system is proved to be the Peierls insulator with a charge density wave of renormalized d electrons of Pt, where the total valence of Pt IV- and Pt 11 is conserved without excess electrons from ligands or anions.

  5. Complexity of case mix in a regional allergy service

    PubMed Central

    2012-01-01

    Background Currently in the United Kingdom (UK), there is a mismatch between limited financial resources and the large proportion of patients with suspected allergies actually being referred to specialist allergy clinics. To better understand the case mix of patients being referred, we audited referrals to a regional allergy service over an 8 year period. The main source of data was consultant letters to General Practitioners (GP) summarising the diagnosis of patients, archived from January 2002 to September 2009. Letters were reviewed, extracting the clinic date, doctor seen, gender, date of birth, postcode, GP, and diagnoses. Diagnoses were classified into seven groups and illustrative cases for each group noted. Findings Data from 2,028 new referrals with suspected allergy were analysed. The largest group of patients (43%) were diagnosed with a type I hypersensitivity. The other diagnostic groups were chronic idiopathic (spontaneous) urticaria (35%), suspected type I hypersensitivity but no allergen identified (8%), idiopathic (spontaneous) angioedema (8%), physical urticaria (2.5%), non-allergic symptoms (1.6%), type IV hypersensitivity (0.8%) and ACE inhibitor sensitivity (0.5%). Two thirds of patients seen were female with a higher percentage of female patients in the non type-I hypersensitivity group (71%) than the type 1 hypersensitivity (66%) (χ2 = 5.1, 1df, p = 0.024). The type 1 hypersensitivity patients were younger than other patients (38 Vs 46 years, t = -10.8, p < 0.001) Conclusions This study highlights the complexity of specialist allergy practice and the large proportion of patients referred with non-type I hypersensitivities, chronic idiopathic (spontaneous) urticaria being by far the largest group. Such information is critical to inform commissioning decisions, define referral pathways and in primary care education. PMID:22340023

  6. Using mixed methods to develop and evaluate complex interventions in palliative care research.

    PubMed

    Farquhar, Morag C; Ewing, Gail; Booth, Sara

    2011-12-01

    there is increasing interest in combining qualitative and quantitative research methods to provide comprehensiveness and greater knowledge yield. Mixed methods are valuable in the development and evaluation of complex interventions. They are therefore particularly valuable in palliative care research where the majority of interventions are complex, and the identification of outcomes particularly challenging. this paper aims to introduce the role of mixed methods in the development and evaluation of complex interventions in palliative care, and how they may be used in palliative care research. the paper defines mixed methods and outlines why and how mixed methods are used to develop and evaluate complex interventions, with a pragmatic focus on design and data collection issues and data analysis. Useful texts are signposted and illustrative examples provided of mixed method studies in palliative care, including a detailed worked example of the development and evaluation of a complex intervention in palliative care for breathlessness. Key challenges to conducting mixed methods in palliative care research are identified in relation to data collection, data integration in analysis, costs and dissemination and how these might be addressed. the development and evaluation of complex interventions in palliative care benefit from the application of mixed methods. Mixed methods enable better understanding of whether and how an intervention works (or does not work) and inform the design of subsequent studies. However, they can be challenging: mixed method studies in palliative care will benefit from working with agreed protocols, multidisciplinary teams and engaging staff with appropriate skill sets.

  7. Photo- and electroluminescence of mixed-ligand Eu(III) complexes

    NASA Astrophysics Data System (ADS)

    Eremina, N. S.; Meshkova, S. B.; Degtyarenko, K. M.; Kopylova, T. N.; Topilova, Z. M.; Gadirov, R. M.; Samsonova, L. G.

    2012-05-01

    Spectral and luminescent properties of mixed-ligand Eu(III) complexes were studied in solutions and in polyvinylcarbazole (PVC) thin films. Trends in their variations were found depending on the complex structure and excitation mode. The electroluminescence was observed in ITO/PEDOT/Eu complex:PVC/CaMg/Al devices. Their current-voltage and voltage-brightness characteristics were investigated.

  8. Laboratory simulations of the atmospheric mixed-layer in flow over complex topography

    EPA Science Inventory

    A laboratory study of the influence of complex terrain on the interface between a well-mixed boundary layer and an elevated stratified layer was conducted in the towing-tank facility of the U.S. Environmental Protection Agency. The height of the mixed layer in the daytime boundar...

  9. Cognitive Task Complexity Effects on L2 Writing Performance: An Application of Mixed-Methods Approaches

    ERIC Educational Resources Information Center

    Abdi Tabari, Mahmoud; Ivey, Toni A.

    2015-01-01

    This paper provides a methodological review of previous research on cognitive task complexity, since the term emerged in 1995, and investigates why much research was more quantitative rather than qualitative. Moreover, it sheds light onto the studies which used the mixed-methods approach and determines which version of the mixed-methods designs…

  10. Laboratory simulations of the atmospheric mixed-layer in flow over complex topography

    EPA Science Inventory

    A laboratory study of the influence of complex terrain on the interface between a well-mixed boundary layer and an elevated stratified layer was conducted in the towing-tank facility of the U.S. Environmental Protection Agency. The height of the mixed layer in the daytime boundar...

  11. Electron localization in a mixed-valence diniobium benzene complex

    DOE PAGES

    Gianetti, Thomas L.; Nocton, Grégory; Minasian, Stefan G.; ...

    2014-11-11

    Reaction of the neutral diniobium benzene complex {[Nb(BDI)NtBu]2(μ-C6H6)} (BDI = N,N'-diisopropylbenzene-β-diketiminate) with Ag[B(C6F5)4] results in a single electron oxidation to produce a cationic diniobium arene complex, {[Nb(BDI)NtBu]2(μ-C6H6)}{B(C6F5)4}. Investigation of the solid state and solution phase structure using single-crystal X-ray diffraction, cyclic voltammetry, magnetic susceptibility, and multinuclear NMR spectroscopy indicates that the oxidation results in an asymmetric molecule with two chemically inequivalent Nb atoms. Further characterization using density functional theory (DFT) calculations, UV-visible, Nb L3,2-edge X-ray absorption near-edge structure (XANES), and EPR spectroscopies supports assignment of a diniobium complex, in which one Nb atom carries a single unpaired electron that ismore » not largely delocalized on the second Nb atom. During the oxidative transformation, one electron is removed from the δ-bonding HOMO, which causes a destabilization of the molecule and formation of an asymmetric product. Subsequent reactivity studies indicate that the oxidized product allows access to metal-based chemistry with substrates that did not exhibit reactivity with the starting neutral complex.« less

  12. Electron localization in a mixed-valence diniobium benzene complex

    SciTech Connect

    Gianetti, Thomas L.; Nocton, Grégory; Minasian, Stefan G.; Kaltsoyannis, Nikolas; Kilcoyne, A. L. David; Kozimor, Stosh A.; Shuh, David K.; Tyliszczak, Tolek; Bergman, Robert G.; Arnold, John

    2014-11-11

    Reaction of the neutral diniobium benzene complex {[Nb(BDI)NtBu]2(μ-C6H6)} (BDI = N,N'-diisopropylbenzene-β-diketiminate) with Ag[B(C6F5)4] results in a single electron oxidation to produce a cationic diniobium arene complex, {[Nb(BDI)NtBu]2(μ-C6H6)}{B(C6F5)4}. Investigation of the solid state and solution phase structure using single-crystal X-ray diffraction, cyclic voltammetry, magnetic susceptibility, and multinuclear NMR spectroscopy indicates that the oxidation results in an asymmetric molecule with two chemically inequivalent Nb atoms. Further characterization using density functional theory (DFT) calculations, UV-visible, Nb L3,2-edge X-ray absorption near-edge structure (XANES), and EPR spectroscopies supports assignment of a diniobium complex, in which one Nb atom carries a single unpaired electron that is not largely delocalized on the second Nb atom. During the oxidative transformation, one electron is removed from the δ-bonding HOMO, which causes a destabilization of the molecule and formation of an asymmetric product. Subsequent reactivity studies indicate that the oxidized product allows access to metal-based chemistry with substrates that did not exhibit reactivity with the starting neutral complex.

  13. On complexity of the mixed volume of parallelograms

    SciTech Connect

    Gurvits, Leonid

    2009-01-01

    Let K = (K{sub 1}...K{sub n}) be a n-tuple of convex compact subsets in the Euclidean space R{sup n}, and let V({center_dot}) be the Euclidean volume in R{sup n}. It is well known Herman Minkowski result (see for instance 5), that the value of the V{sub K}({gamma}{sub 1}K{sub 1} + ... {gamma}{sub n}K{sub n}) is a homogeneous polynomial of degree n, called the Minkowski polynomial, in nonnegative variables {gamma}{sub 1}...{gamma}{sub n1}, where '+' denotes Minkowski sum, and {gamma}K denotes the dilatation of K with coefficient {gamma}. The coefficient V(K{sub 1}...K{sub n}) of {gamma}{sub 1}{center_dot}{gamma}{sub 2}...{center_dot}{gamma}{sub n} is called the mixed volume of K{sub 1}...K{sub n}. Alternatively, V(K{sub 1}...K{sub n}) = ({partial_derivative}{sup n} / {partial_derivative}{gamma}{sub 1}...{partial_derivative}{gamma}{sub n})V{sub K}({gamma}{sub 1}K{sub 1}+...{gamma}{sub n}K{sub n}).

  14. Dynamics around solutes and solute-solvent complexes in mixed solvents.

    PubMed

    Kwak, Kyungwon; Park, Sungnam; Fayer, M D

    2007-09-04

    Ultrafast 2D-IR vibrational echo experiments, IR pump-probe experiments, and FT-IR spectroscopy of the hydroxyl stretch of phenol-OD in three solvents, CCl4, mesitylene (1, 3, 5 trimethylbenzene), and the mixed solvent of mesitylene and CCl4 (0.83 mole fraction CCl4), are used to study solute-solvent dynamics via observation of spectral diffusion. Phenol forms a complex with Mesitylene. In the mesitylene solution, there is only complexed phenol; in the CCl4 solution, there is only uncomplexed phenol; and in the mixed solvent, both phenol species are present. Dynamics of the free phenol in CCl4 or the mixed solvent are very similar, and dynamics of the complex in mesitylene and in the mixed solvent are very similar. However, there are differences in the slowest time scale dynamics between the pure solvents and the mixed solvents. The mixed solvent produces slower dynamics that are attributed to first solvent shell solvent composition variations. The composition variations require a longer time to randomize than is required in the pure solvents, where only density variations occur. The experimental results and recent MD simulations indicate that the solvent structure around the solute may be different from the mixed solvent's mole fraction.

  15. Structural and Functional Association of Trypanosoma brucei MIX Protein with Cytochrome c Oxidase Complex ▿ †

    PubMed Central

    Zíková, Alena; Panigrahi, Aswini K.; Uboldi, Alessandro D.; Dalley, Rachel A.; Handman, Emanuela; Stuart, Kenneth

    2008-01-01

    A mitochondrial inner membrane protein, designated MIX, seems to be essential for cell viability. The deletion of both alleles was not possible, and the deletion of a single allele led to a loss of virulence and aberrant mitochondrial segregation and cell division in Leishmania major. However, the mechanism by which MIX exerts its effect has not been determined. We show here that MIX is also expressed in the mitochondrion of Trypanosoma brucei, and using RNA interference, we found that its loss leads to a phenotype that is similar to that described for Leishmania. The loss of MIX also had a major effect on cytochrome c oxidase activity, on the mitochondrial membrane potential, and on the production of mitochondrial ATP by oxidative phosphorylation. Using a tandem affinity purification tag, we found that MIX is associated with a multiprotein complex that contains subunits of the mitochondrial cytochrome c oxidase complex (respiratory complex IV), the composition of which was characterized in detail. The specific function of MIX is unknown, but it appears to be important for the function of complex IV and for mitochondrial segregation and cell division in T. brucei. PMID:18776036

  16. Lagrangian simulation of mixing and reactions in complex geochemical systems

    NASA Astrophysics Data System (ADS)

    Engdahl, Nicholas B.; Benson, David A.; Bolster, Diogo

    2017-04-01

    Simulations of detailed geochemical systems have traditionally been restricted to Eulerian reactive transport algorithms. This note introduces a Lagrangian method for modeling multicomponent reaction systems. The approach uses standard random walk-based methods for the particle motion steps but allows the particles to interact with each other by exchanging mass of their various chemical species. The colocation density of each particle pair is used to calculate the mass transfer rate, which creates a local disequilibrium that is then relaxed back toward equilibrium using the reaction engine PhreeqcRM. The mass exchange is the only step where the particles interact and the remaining transport and reaction steps are entirely independent for each particle. Several validation examples are presented, which reproduce well-known analytical solutions. These are followed by two demonstration examples of a competitive decay chain and an acid-mine drainage system. The source code, entitled Complex Reaction on Particles (CRP), and files needed to run these examples are hosted openly on GitHub (https://github.com/nbengdahl/CRP), so as to enable interested readers to readily apply this approach with minimal modifications.

  17. A Survey of Mixed-Waste HEPA Filters in the DOE Complex

    SciTech Connect

    Felicione, F. S.; Barber, D. B.; Carney, K. P.

    2002-02-28

    A brief investigation was made to determine the quantities of spent, mixed-waste HEPA filters within the DOE Complex. The quantities of both the mixed-waste filters that are currently being generated, as well as the legacy mixed-waste filters being stored and awaiting disposition were evaluated. Seven DOE sites representing over 89% of the recent HEPA filter usage were identified. These sites were then contacted to determine the number of these filters that were likely destined to become mixed waste and to survey the legacy-filter quantities. Inquiries into the disposition plans for the filters were also made. It was determined that the seven sites surveyed possess approximately 500 m3 of legacy mixed-waste HEPA filters that will require processing, with an annual generation rate of approximately 25 m3. No attempt was made to extrapolate the results of this survey to the entire DOE Complex. These results were simply considered to be the lower bound of the totality of mixed-waste HEPA filters throughout the Complex. The quantities determined encourage the development of new treatment technologies for these filters, and provide initial data on which an appropriate capacity for a treatment process may be based.

  18. Chemical Composition of Martian Soil and Rocks: Complex Mixing and Sedimentary Transport

    NASA Technical Reports Server (NTRS)

    McLennan, Scott M.

    2000-01-01

    Chemical compositions of Martian soil and rocks indicate complex mixing relationships. Mixing of rock and soil clearly takes place and explains some of the chemical variation because sulfur, chlorine, magnesium, and perhaps iron are positively correlated due to their control from a secondary 'sedimentary' mineralogy (e.g., Mg- and possibly Fe-sulfate; Fe-oxides) that is present within the soils. Certain deviations from simple soil-rock mixing are consistent with mineralogical fractionation of detrital iron and titanium oxides during sedimentary transport.

  19. The configurational entropy of mixing of metastable random solid solution in complex multicomponent alloys

    NASA Astrophysics Data System (ADS)

    He, Q. F.; Ye, Y. F.; Yang, Y.

    2016-10-01

    Since the advent of "high-entropy" alloys, the simple ideal mixing rule has been commonly used to calculate the configurational entropy of mixing for these multicomponent alloys. However, there have been increasing experimental evidence reported recently showing that the ideal mixing rule tends to overestimate the configurational entropy of mixing in the multicomponent alloys, particularly at a low temperature. In contrast to the ideal mixing rule, here we provide a formula to assess the configurational entropy of mixing in random solid-solution multicomponent alloys by considering the possible correlations among the constituent elements due to various factors, such as atomic size misfit and chemic bond misfit, which may disturb the potential energy of the system and thus reduce the configurational entropy of mixing. With our entropy formulation, the correlation is explored between the configuration entropy of mixing of different alloys and the general character of the phases formed, such as single- or multiple-phased crystalline phase versus amorphous phase. Being in good agreement with the simulation and experimental results, our work provides an analytical framework that could be further used to explore phase stability in complex multicomponent alloys.

  20. Neptunium(vi) chain and neptunium(vi/v) mixed valence cluster complexes.

    PubMed

    Cornet, Stéphanie M; Häller, L Jonas L; Sarsfield, Mark J; Collison, David; Helliwell, Madeleine; May, Iain; Kaltsoyannis, Nikolas

    2009-02-28

    The synthesis of [Np(VI)O(2)Cl(2)(thf)](n) offers the potential for more detailed exploration of neptunyl(vi) chemistry, while the synthesis of the mixed valence cluster complex [{Np(VI)O(2)Cl(2)}{Np(V)O(2)Cl(thf)(3)}(2)] allows molecular neptunyl(v) 'cation-cation' interactions to be probed.

  1. The Complexities of Teachers' Commitment to Environmental Education: A Mixed Methods Approach

    ERIC Educational Resources Information Center

    Sosu, Edward M.; McWilliam, Angus; Gray, Donald S.

    2008-01-01

    This article argues that a mixed methods approach is useful in understanding the complexity that underlies teachers' commitment to environmental education. Using sequential and concurrent procedures, the authors demonstrate how different methodological approaches highlighted different aspects of teacher commitment. The quantitative survey examined…

  2. What We Learned about Mentoring Research Assistants Employed in a Complex, Mixed-Methods Health Study

    ERIC Educational Resources Information Center

    Weeks, Lori E.; Villeneuve, Michelle A.; Hutchinson, Susan; Roger, Kerstin; Versnel, Joan; Packer, Tanya

    2015-01-01

    We investigated the experiences of research assistants in their dual role as both employees and trainees, when they were employed in a complex, mixed-methods, Canadian study on the everyday experience of living with and managing a chronic condition. A total of 13 research assistants participated in one or more components of this study: a survey (n…

  3. Laboratory simulations of the atmospheric mixed-layer in flow over complex topography

    NASA Astrophysics Data System (ADS)

    Perry, Steven G.; Snyder, William H.

    2017-02-01

    A laboratory study of the influence of complex terrain on the interface between a well-mixed boundary layer and an elevated stratified layer was conducted in the towing-tank facility of the U.S. Environmental Protection Agency. The height of the mixed layer in the daytime boundary layer can have a strong influence on the concentration of pollutants within this layer. Deflections of streamlines at the height of the interface are primarily a function of hill Froude number (Fr), the ratio of mixed-layer height (zi) to terrain height (h), and the crosswind dimension of the terrain. The magnitude of the deflections increases as Fr increases and zi/h decreases. For mixing-height streamlines that are initially below the terrain top, the response is linear with Fr; for those initially above the terrain feature the response to Fr is more complex. Once Fr exceeds about 2, the terrain-related response of the mixed layer interface decreases somewhat with increasing Fr (toward more neutral flow). Deflections are also shown to increase as the crosswind dimensions of the terrain increase. Comparisons with numerical modeling, limited field data, and other laboratory measurements reported in the literature are favorable. Additionally, visual observations of dye streamers suggest that the flow structure exhibited for our elevated inversions passing over three dimensional hills is similar to that reported in the literature for continuously stratified flow over two-dimensional hills.

  4. Molecular organization of a water-insoluble iridium(III) complex in mixed monolayers.

    PubMed

    Giner-Casares, Juan J; Pérez-Morales, Marta; Bolink, Henk J; Muñoz, Eulogia; de Miguel, Gustavo; Martín-Romero, María T; Camacho, Luis

    2007-11-01

    In this work, organized mixed monolayers containing a cationic water-insoluble iridium(III) complex, Ir-dye, [Ir(ppy)(2)(tmphen)]PF(6), (tmphen = 3,4,7,8-tetramethyl-1,10-phenanthroline, and ppy = 2-phenylpyridine), and an anionic lipid matrix, DMPA, dimyristoyl-phosphatidic acid, with different molar proportions, were formed by the co-spreading method at the air-water interface. The presence of the dye at the interface, as well as the molecular organization of the mixed films, is deduced from surface techniques such as pi-A isotherms, Brewster angle microscopy (BAM) and reflection spectroscopy. The results obtained remark the formation of an equimolar mixed film, Ir-dye/DMPA = 1:1. BAM images reveal a whole homogeneous monolayer, with gradually increasing reflectivity along the compression process up to reaching the collapse of this equimolecular monolayer at pi approximately equal to 37 mNm(-1). Increasing the molar ratio of DMPA in the mixture, the excess of lipid molecules organizes themselves forming dark flower-like domains of pure DMPA at high surface pressures, coexisting with the mixed Ir-dye/DMPA = 1:1 monolayer. On the other hand, unstable mixed monolayers are obtained by using an initial dye surface concentration higher than the equimolecular one. These mixed Langmuir monolayers have been successfully transferred onto solid substrates by the LB (Langmuir-Blodgett) technique.

  5. Rotational State Microwave Mixing for Laser Cooling of Complex Diatomic Molecules

    NASA Astrophysics Data System (ADS)

    Yeo, Mark; Hummon, Matthew T.; Collopy, Alejandra L.; Yan, Bo; Hemmerling, Boerge; Chae, Eunmi; Doyle, John M.; Ye, Jun

    2015-06-01

    We demonstrate the mixing of rotational states in the ground electronic state using microwave radiation to enhance optical cycling in the molecule yttrium (II) monoxide (YO). This mixing technique is used in conjunction with a frequency modulated and chirped continuous wave laser to slow longitudinally a cryogenic buffer-gas beam of YO. We generate a flux of YO below 10 m /s , directly loadable into a three-dimensional magneto-optical trap. This technique opens the door for laser cooling of diatomic molecules with more complex loss channels due to intermediate states.

  6. EXAFS Studies of Some Copper(II) Mixed-Ligand Complexes

    SciTech Connect

    Joshi, S. K.; Katare, R. K.; Shrivastava, B. D.

    2007-02-02

    X-ray K-absorption spectroscopic studies have been carried out on copper (II) mixed-ligand complexes with glutamic acid and aspartic acid as the primary ligands, where as water, pyridine, imidazole and benz-imidazole have been used as secondary ligands. Chemical shifts obtained from the X-ray absorption data have indicated that the glutamic acid complexes are more ionic as compared to their corresponding aspartic acid complexes having similar secondary ligands. Further, we have estimated the average metal-ligand bond distances from the from structure data. For the different complexes studied under the present investigation, the studies reveal that the bonding parameter {alpha}1 decreases with the increase in the percentage covalency of the metal-ligand bond. Thus, the bonding parameter {alpha}1 may be used for the estimation of percentage covalency of the metal-ligand bond in other similar complexes.

  7. Di- and Trinuclear Mixed-Valence Copper Amidinate Complexes from Reduction of Iodine

    PubMed Central

    Lane, Andrew C.; Barnes, Charles L.; Antholine, William E.; Wang, Denan; Fiedler, Adam T.; Walensky, Justin R.

    2016-01-01

    Molecular examples of mixed-valence copper complexes through chemical oxidation are rare but invoked in the mechanism of substrate activation, especially oxygen, in copper-containing enzymes. To examine the cooperative chemistry between two metals in close proximity to each other we have begun to study the reactivity of a dinuclear Cu(I) amidinate complex. The reaction of [(2,6-Me2C6H3N)2C(H)]2Cu2, 1, with I2 in THF, CH3CN, and toluene affords three new mixed-valence copper complexes, [(2,6-Me2C6H3N)2C(H)]2Cu2(μ2-I3)(THF)2, 2, [(2,6-Me2C6H3N)2C(H)]2Cu2(μ2-I)(NCMe)2, 3, and [(2,6-Me2C6H3N)2C(H)]3Cu3(μ3-I)2, 4, respectively. The first two compounds have been characterized by UV-Vis and EPR spectroscopy and their molecular structure determined by X-ray crystallography. Both di- and trinuclear mixed-valence intermediates have been characterized for the reaction of compound 1 to compound 4 and the molecular structure of 4 has been determined by X-ray crystallography. The electronic structure of each of these complexes has also been investigated using density functional theory. PMID:26252561

  8. Mixed donor quinone complexes of nickel, zinc, cobalt, manganese and vanadium

    SciTech Connect

    Scotto, C.S.

    1992-01-01

    Mixed donor complexes of several first row metals have been prepared and examined for variations in redox properties, charge distribution and stability in comparison with homoleptic metal quinone species. Schiff base condensation between 3,5-di-tert-butylcatechol and ammonia provided the 3,5 di-tert-butyl-1,2-quinone-1-(2-hydroxy-3,5-di-tert-butlyphenyl)imine ligand for known M(QNQ)[sub 2] compounds. X-ray diffraction, cyclic voltammetry and solution susceptibility measurements were employed to compare properties with the pure quinone complexes and, in the case of Mn(QNQ)[sub 2] and CO(QNQ)[sub 2], with mixed ligand pyridyl quinone compounds of the two metals. Synthesis of the V(QNQ)[sub 2] analog was undertaken with partial characterization achieved through EPR, cyclic voltammetry and mass spectrometry. The vanadium chemistry was extended to mixed ligand catecholate complexes of V[sup III] and V[sup IV]. Such species are currently of interest in tunicate vanadium studies and in the catalytic oxygenation of pyrocatechols. Tetrachlorocatecholate analogs of known compounds were prepared and fully characterized. The x-ray structure of V(bipyridyl)(tetrachlorocatecholate)[sub 2] provided an unusual example of trigonal prismataic geometry about the metal center. A proposed intermediate in the synthesis of the target complex anion [V(bipyridyl)(tetrachlorocatecholate)[sub 2

  9. Di- and Trinuclear Mixed-Valence Copper Amidinate Complexes from Reduction of Iodine.

    PubMed

    Lane, Andrew C; Barnes, Charles L; Antholine, William E; Wang, Denan; Fiedler, Adam T; Walensky, Justin R

    2015-09-08

    Molecular examples of mixed-valence copper complexes through chemical oxidation are rare but invoked in the mechanism of substrate activation, especially oxygen, in copper-containing enzymes. To examine the cooperative chemistry between two metals in close proximity to each other we began studying the reactivity of a dinuclear Cu(I) amidinate complex. The reaction of [(2,6-Me2C6H3N)2C(H)]2Cu2, 1, with I2 in tetrahydrofuran (THF), CH3CN, and toluene affords three new mixed-valence copper complexes [(2,6-Me2C6H3N)2C(H)]2Cu2(μ2-I3)(THF)2, 2, [(2,6-Me2C6H3N)2C(H)]2Cu2(μ2-I) (NCMe)2, 3, and [(2,6-Me2C6H3N)2C(H)]3Cu3(μ3-I)2, 4, respectively. The first two compounds were characterized by UV-vis and electron paramagnetic resonance spectroscopies, and their molecular structure was determined by X-ray crystallography. Both di- and trinuclear mixed-valence intermediates were characterized for the reaction of compound 1 to compound 4, and the molecular structure of 4 was determined by X-ray crystallography. The electronic structure of each of these complexes was also investigated using density functional theory.

  10. Wave-induced upper-ocean mixing in a climate model of intermediate complexity

    NASA Astrophysics Data System (ADS)

    Babanin, Alexander V.; Ganopolski, Andrey; Phillips, William R. C.

    Climate modelling, to a great extent, is based on simulating air-sea interactions at larger scales. Small-scale interactions and related phenomena, such as wind-generated waves and wave-induced turbulence are sub-grid processes for such models and therefore cannot be simulated explicitly. In the meantime, the waves play the principal role in the upper-ocean mixing. This role is usually parameterized, mostly to account for the wave-breaking turbulence and to describe downward diffusion of such turbulence. The main purpose of the paper is to demonstrate that an important physical mechanism, that is the ocean mixing due to waves, is presently missing in the climate models, whereas the effect of this mixing is significant. It is argued that the mixing role of the surface waves is not limited to the mere transfer of the wind stress and energy across the ocean interface by means of breaking and surface currents. The waves facilitate two processes in the upper-ocean which can deliver turbulence to the depths of the order of 100 m directly, rather than diffusing it from the surface. The first process is due to capacity of the waves to generate turbulence, unrelated to the wave breaking, at all depths where the wave orbital motion is significant. The second process is Langmuir circulation, triggered by the waves. Such wave-controlled mixing should cause seasonal variations of the mixed-layer depth, which regulates the thermodynamic balance between the ocean and atmosphere. In the present paper, these variations are parameterized in terms of the global winds. The variable mixed-layer depth is then introduced in the climate model of intermediated complexity CLIMBER-2 with a purpose of reproducing the pre-industrial climate. Comparisons are conducted with the NRL global atlas of the mixed layer, and performance of the wave-mixing parameterisations was found satisfactory in circumstances where the mixing is expected to be dominated by the wind-generated waves. It is shown that

  11. Complex permittivity measurements and mixing laws of ceramic materials and application to microwave processing

    NASA Astrophysics Data System (ADS)

    Gershon, David Louis

    The complex permittivity of alumina composites was examined with respect to its dependence on the volume fraction of constituents, microstructure, processing temperature, and processing method. In addition, the effective permittivity of these composites was quantitatively modeled based on the permittivities, volume fractions, and microstructures of the constituents. The studies focused on the complex permittivity of alumina composites, which contained the lossy additives silicon carbide and copper oxide. Two composite systems were prepared by physically mixing alumina and one of the additives. A third composite system was produced by chemically precipitating copper oxide onto alumina. The two synthesis methods produced composites with different microstructures and complex permittivities. The imaginary part of the complex permittivity was generally larger in the chemically precipitated composites than in the physically mixed composites. The dependence of the complex permittivities of the composites on volume fraction and microstructure were compared with several algebraic mixing laws and with three dimensional, electrostatic numerical simulations. The algebraic mixing laws do not take into account for the dependence of the imaginary part of the complex permittivity on absorbed water and microstructure, which is affected by composite synthesis. By incorporating general physical characteristics of the composites, the electrostatic simulations were able to accurately predict their permittivity. Heating some selected alumina composites in conventional and microwave furnaces demonstrate several interesting results. The densification and dielectric proper-ties of the alumina/copper oxide composites varied due to processing temperature. The changes in these properties depended upon preparation method and not on heating method. The density and real part of the complex permittivity of alumina/silicon carbide also varied due to processing temperature and not on heating method

  12. Synthesis and spectral characterization of ternary mixed-vanadyl β-diketonate complexes with Schiff bases.

    PubMed

    Baranwal, Balram Prasad; Tripathi, Kiran; Singh, Alok Kumar; Tripathi, Saurabh

    2012-06-01

    A new method to synthesize some mononuclear ternary oxovanadium(IV) complexes of the general formula [VO(β-dike)(SB)] (where Hβ-dike=acetylacetone; benzoylacetone or dibenzoylmethane, HSB=Schiff bases) has been explored by stepwise substitutions of acetylacetonate ion of VO(acac)(2) with Schiff bases. The substituted acetylacetone could be fractionated out with p-xylene as an azeotrope. The complexes were characterized by elemental analyses, molecular weight determinations, spectral (electronic, infrared, (1)H NMR, EPR and powder XRD) studies, magnetic susceptibility measurements and cyclic voltammetry. Molar conductance measurements indicated the complexes to be non-electrolytes in nitrobenzene. Bidentate chelating nature of β-diketones and Schiff base anions in the complexes was established by infrared and NMR spectra. Molecular weight determinations confirmed mononuclear nature of the complexes. The EPR spectra illustrated coupling of the unpaired electron with (51)V nucleus (I=7/2). Cyclic voltammograms of all the complexes displayed two-step oxidation processes. The oxidation peak potential corresponded to the quasireversible one-electron oxidation process of the metal center, yielding V(V) species. Transmission electron microscopy (TEM) indicated spherical particles of ∼200 nm diameter. The synthesized complexes are mixed-ligand complexes showing a considerable hydrolytic stability in which vanadium is having coordination number 5. A square pyramidal geometry around vanadium has been assigned in all the complexes.

  13. [Characteristics of mixed association and deactivation of electron excitation in chlorophyll-pheophytin complexes].

    PubMed

    Zen'kevich, E I; Zen'kevich, T V

    1984-01-01

    The regularities of the individual and mixed association of chlorophylls (Chl a, PChl a) with pheophytin (Pheo) were investigated. The complex studies of optical activity, spectral--luminescent and energetic characteristics of aggregates were carried out in mixture of solvents aceton-water (1:49). The formation of pigment mixed associates leads to intracomplex energy transfer from Chl (or PChl) to Pheo. It is shown that the efficiencies of such process, determined by independent ways via the luminescence quenching of energy donor or the emission sensibilization of acceptor, are identical. The energy migration mechanism is the inductive resonance one in studied complexes. The main patterns of the electronic excitation energy deactivation in such systems are discussed. The obtained results are analysed taking into account the contemporary background of the role of pheophytin in the primary processes of photosynthesis.

  14. Spectroscopic characterisation of indium(III) chloride and mixed ligand complexes

    NASA Astrophysics Data System (ADS)

    Kloo, Lars; Taylor, Michael J.

    2002-03-01

    Acidic solutions of InCl 3 plus InBr 3 contain mixed halide complexes and solvent extraction yields the four-coordinate anions InCl nBr 4- n- whose ν(InCl) and ν(InBr) modes are reported. Two solid products of InCl 3 with 15-crown-5 have been identified; crystallisation from aqueous HCl gave a molecular adduct containing InCl 3(H 2O) 2, whereas the ionic complex [InCl 2(15-crown-5)][InCl 4] was produced under anhydrous conditions. The vibrational spectra are assigned.

  15. Complexes with mixed primary and secondary cellulose synthases are functional in Arabidopsis thaliana plants

    SciTech Connect

    Carroll, Andrew; Mansoori, N; Li, Shundai; Lei, Lei; Vernhettes, Samantha; Visser, Richard G. F.; Somerville, Chris R; Gu, Ying; Trindade, Luisa M.

    2012-10-01

    In higher plants, cellulose is synthesized by so-called rosette protein complexes with cellulose synthases (CESAs) as catalytic subunits of the complex. The CESAs are divided into two distinct families, three of which are thought to be specialized for the primary cell wall and three for the secondary cell wall. In this article, the potential of primary and secondary CESAs forming a functional rosette complex has been investigated. The membrane-based yeast two-hybrid and biomolecular fluorescence systems were used to assess the interactions between three primary (CESA1, CESA3, CESA6), and three secondary (CESA4, CESA7, CESA8) Arabidopsis (Arabidopsis thaliana) CESAs. The results showed that all primary CESAs can physically interact both in vitro and in planta with all secondary CESAs. Although CESAs are broadly capable of interacting in pairwise combinations, they are not all able to form functional complexes in planta. Analysis of transgenic lines showed that CESA7 can partially rescue defects in the primary cell wall biosynthesis in a weak cesa3 mutant. Green fluorescent protein-CESA protein fusions revealed that when CESA3 was replaced by CESA7 in the primary rosette, the velocity of the mixed complexes was slightly faster than the native primary complexes. CESA1 in turn can partly rescue defects in secondary cell wall biosynthesis in a cesa8ko mutant, resulting in an increase of cellulose content relative to cesa8ko. These results demonstrate that sufficient parallels exist between the primary and secondary complexes for cross-functionality and open the possibility that mixed complexes of primary and secondary CESAs may occur at particular times.

  16. Enthused research on DNA-binding and DNA-cleavage aptitude of mixed ligand metal complexes

    NASA Astrophysics Data System (ADS)

    Mahalakshmi, Rajkumar; Raman, Natarajan

    2013-08-01

    Five new Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) mixed ligand complexes have been synthesized using a Schiff base precursor (obtained by the condensation of N-(4-aminophenyl)acetamide and 4-chlorobenzaldehyde) as main ligand and 1,10-phenanthroline as co-ligand. They have been characterized by microanalytical data, IR, UV-Vis, magnetic moment values, conductivity and electrochemical measurements. The spectral data reveal that all the complexes exhibit octahedral geometry. The high electrical conductance of the complexes supports their electrolytic nature. The monomeric nature of the complexes has been assessed from their magnetic susceptibility values. These complexes are better antimicrobial active agents than the free ligands. DNA (CT) binding properties of these complexes have been explored by UV-Vis., viscosity measurements, cyclic voltammetry, and differential pulse voltammetry measurements. The oxidative cleavage activity of the complexes has been studied using supercoiled pUC19 DNA by gel electrophoresis. The experimental results show that the complexes are good intercalators.

  17. Enthused research on DNA-binding and DNA-cleavage aptitude of mixed ligand metal complexes.

    PubMed

    Mahalakshmi, Rajkumar; Raman, Natarajan

    2013-08-01

    Five new Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) mixed ligand complexes have been synthesized using a Schiff base precursor (obtained by the condensation of N-(4-aminophenyl)acetamide and 4-chlorobenzaldehyde) as main ligand and 1,10-phenanthroline as co-ligand. They have been characterized by microanalytical data, IR, UV-Vis, magnetic moment values, conductivity and electrochemical measurements. The spectral data reveal that all the complexes exhibit octahedral geometry. The high electrical conductance of the complexes supports their electrolytic nature. The monomeric nature of the complexes has been assessed from their magnetic susceptibility values. These complexes are better antimicrobial active agents than the free ligands. DNA (CT) binding properties of these complexes have been explored by UV-Vis., viscosity measurements, cyclic voltammetry, and differential pulse voltammetry measurements. The oxidative cleavage activity of the complexes has been studied using supercoiled pUC19 DNA by gel electrophoresis. The experimental results show that the complexes are good intercalators.

  18. Sensitized photo- and electroluminescence from Er complexes mixed with Ir complex

    NASA Astrophysics Data System (ADS)

    Zhang, Dongyu; Li, Wenlian; Chu, Bei; Li, Xiao; Han, Liangliang; Zhu, Jianzhuo; Li, Tianle; Bi, Defeng; Yang, Dongfang; Yan, Fei; Liu, Huihui; Wang, Dan

    2008-03-01

    We investigated the sensitized effect of fac-tris(2-phenylpyridine) iridium [Ir(ppy)3] on tris-(dibenzoylmethanato)-mono-(bathophenanthroline) erbium (Er-DB) for 1.5μm near-infrared emission. Compared with the neat Er-DB film, the blend film composed of Er-DB and Ir(ppy)3 with a 1:1 of the weight ratio shows 20 times and 4 times enhancement on intensity of photoluminescence (PL) and electroluminescence (EL), respectively. The improvement in both PL and EL intensities was conjectured to be the result of the energy transfer from Ir(ppy)3 to Er-DB complex, and the detailed mechanisms of the enhancement were also discussed.

  19. Tah1 helix-swap dimerization prevents mixed Hsp90 co-chaperone complexes

    SciTech Connect

    Morgan, Rhodri M. L.; Pal, Mohinder; Roe, S. Mark; Pearl, Laurence H. Prodromou, Chrisostomos

    2015-05-01

    A helix swap involving the fifth helix between two adjacently bound Tah1 molecules restores the normal binding environment of the conserved MEEVD peptide of Hsp90. Dimerization also explains how other monomeric TPR-domain proteins are excluded from forming inappropriate mixed co-chaperone complexes with Hsp90 and Tah1. Specific co-chaperone adaptors facilitate the recruitment of client proteins to the Hsp90 system. Tah1 binds the C-terminal conserved MEEVD motif of Hsp90, thus linking an eclectic set of client proteins to the R2TP complex for their assembly and regulation by Hsp90. Rather than the normal complement of seven α-helices seen in other tetratricopeptide repeat (TPR) domains, Tah1 unusually consists of the first five only. Consequently, the methionine of the MEEVD peptide remains exposed to solvent when bound by Tah1. In solution Tah1 appears to be predominantly monomeric, and recent structures have failed to explain how Tah1 appears to prevent the formation of mixed TPR domain-containing complexes such as Cpr6–(Hsp90){sub 2}–Tah1. To understand this further, the crystal structure of Tah1 in complex with the MEEVD peptide of Hsp90 was determined, which shows a helix swap involving the fifth α-helix between two adjacently bound Tah1 molecules. Dimerization of Tah1 restores the normal binding environment of the bound Hsp90 methionine residue by reconstituting a TPR binding site similar to that in seven-helix-containing TPR domain proteins. Dimerization also explains how other monomeric TPR-domain proteins are excluded from forming inappropriate mixed co-chaperone complexes.

  20. Association between polyclonal and mixed mycobacterial Mycobacterium avium complex infection and environmental exposure.

    PubMed

    Fujita, Kohei; Ito, Yutaka; Hirai, Toyohiro; Kubo, Takeshi; Maekawa, Koichi; Togashi, Kaori; Ichiyama, Satoshi; Mishima, Michiaki

    2014-01-01

    Polyclonal and mixed mycobacterial Mycobacterium avium complex (MAC) infection is observed in pulmonary MAC disease. Human living environments contain multiple species or genotypes of nontuberculous mycobacterial strains and are considered sources of infection. To investigate the association of environmental exposure with polyclonal and mixed mycobacterial infection in pulmonary MAC disease after adjustments for potential confounding diseases and conditions and radiographic findings. We collected two separate sputum samples from 102 patients and single sputum samples from 18 patients in whom the second MAC strain was not isolated in our prospective cohort of pulmonary MAC disease. MAC isolates from sputum samples and patients' residential soils were used for variable number of tandem repeats (VNTR) analyses. Polyclonal and mixed mycobacterial MAC infections were defined as having different VNTR genotypes and other mycobacterial species, respectively. Monoclonal MAC infection was defined as all isolates showing a single VNTR genotype. Associations of the type of infection with clinical and radiographic findings and environmental exposure were measured. Polyclonal and mixed mycobacterial MAC and monoclonal infections were observed in 42 and 78 patients, respectively. By stepwise regression analysis, patients with polyclonal and mixed mycobacterial MAC infections were associated with history of asthma (odds ratio [OR], 11.56; 95% confidence interval [CI], 1.41-255.77; P = 0.021), high soil exposure (≥2 h/wk; OR, 4.31; 95% CI, 1.72-11.45; P < 0.01), shower use in a bathroom (OR, 4.57; 95% CI, 1.28-23.23; P = 0.018), and swimming in a pool (OR, 9.69; 95% CI, 1.21-206.92; P < 0.01). Environmental exposure was associated with polyclonal and mixed mycobacterial MAC infection in pulmonary MAC disease.

  1. Spectroscopic studies on Solvatochromism of mixed-chelate copper(II) complexes using MLR technique.

    PubMed

    Golchoubian, Hamid; Moayyedi, Golasa; Fazilati, Hakimeh

    2012-01-01

    Mixed-chelate copper(II) complexes with a general formula [Cu(acac)(diamine)]X where acac=acetylacetonate ion, diamine=N,N-dimethyl,N'-benzyl-1,2-diaminoethane and X=BPh(4)(-), PF(6)(-), ClO(4)(-) and BF(4)(-) have been prepared. The complexes were characterized on the basis of elemental analysis, molar conductance, UV-vis and IR spectroscopies. The complexes are solvatochromic and their solvatochromism were investigated by visible spectroscopy. All complexes demonstrated the positive solvatochromism and among the complexes [Cu(acac)(diamine)]BPh(4)·H(2)O showed the highest Δν(max) value. To explore the mechanism of interaction between solvent molecules and the complexes, different solvent parameters such as DN, AN, α and β using multiple linear regression (MLR) method were employed. The statistical results suggested that the DN parameter of the solvent plays a dominate contribution to the shift of the d-d absorption band of the complexes.

  2. Developing theory from complexity: reflections on a collaborative mixed method participatory action research study.

    PubMed

    Westhues, Anne; Ochocka, Joanna; Jacobson, Nora; Simich, Laura; Maiter, Sarah; Janzen, Rich; Fleras, Augie

    2008-05-01

    Research studies are increasingly complex: They draw on multiple methods to gather data, generate both qualitative and quantitative data, and frequently represent the perspectives of more than one stakeholder. The teams that generate them are increasingly multidisciplinary. A commitment to engaging community members in the research process often adds a further layer of complexity. How to approach a synthesizing analysis of these multiple and varied data sources with a large research team requires considerable reflection and dialogue. In this article, we outline the strategies used by one multidisciplinary team committed to a participatory action research (PAR) approach and engaged in a mixed method program of research to synthesize the findings from four subprojects into a conceptual framework that could guide practice in community mental health organizations. We also summarize factors that hold promise for increasing productivity when managing complex research projects.

  3. Experimental and computational fluid dynamic studies of mixing for complex oral health products

    NASA Astrophysics Data System (ADS)

    Garcia, Marti Cortada; Mazzei, Luca; Angeli, Panagiota

    2015-11-01

    Mixing high viscous non-Newtonian fluids is common in the consumer health industry. Sometimes this process is empirical and involves many pilot plants trials which are product specific. The first step to study the mixing process is to build on knowledge on the rheology of the fluids involved. In this research a systematic approach is used to validate the rheology of two liquids: glycerol and a gel formed by polyethylene glycol and carbopol. Initially, the constitutive equation is determined which relates the viscosity of the fluids with temperature, shear rate, and concentration. The key variable for the validation is the power required for mixing, which can be obtained both from CFD and experimentally using a stirred tank and impeller of well-defined geometries at different impeller speeds. A good agreement between the two values indicates a successful validation of the rheology and allows the CFD model to be used for the study of mixing in the complex vessel geometries and increased sizes encountered during scale up.

  4. Mixed DNA/Oligo(ethylene glycol) Functionalized Gold Surface Improve DNA Hybridization in Complex Media

    SciTech Connect

    Lee,C.; Gamble, L.; Grainger, D.; Castner, D.

    2006-01-01

    Reliable, direct 'sample-to-answer' capture of nucleic acid targets from complex media would greatly improve existing capabilities of DNA microarrays and biosensors. This goal has proven elusive for many current nucleic acid detection technologies attempting to produce assay results directly from complex real-world samples, including food, tissue, and environmental materials. In this study, we have investigated mixed self-assembled thiolated single-strand DNA (ssDNA) monolayers containing a short thiolated oligo(ethylene glycol) (OEG) surface diluent on gold surfaces to improve the specific capture of DNA targets from complex media. Both surface composition and orientation of these mixed DNA monolayers were characterized with x-ray photoelectron spectroscopy (XPS) and near-edge x-ray absorption fine structure (NEXAFS). XPS results from sequentially adsorbed ssDNA/OEG monolayers on gold indicate that thiolated OEG diluent molecules first incorporate into the thiolated ssDNA monolayer and, upon longer OEG exposures, competitively displace adsorbed ssDNA molecules from the gold surface. NEXAFS polarization dependence results (followed by monitoring the N 1s{yields}{pi}* transition) indicate that adsorbed thiolated ssDNA nucleotide base-ring structures in the mixed ssDNA monolayers are oriented more parallel to the gold surface compared to DNA bases in pure ssDNA monolayers. This supports ssDNA oligomer reorientation towards a more upright position upon OEG mixed adlayer incorporation. DNA target hybridization on mixed ssDNA probe/OEG monolayers was monitored by surface plasmon resonance (SPR). Improvements in specific target capture for these ssDNA probe surfaces due to incorporation of the OEG diluent were demonstrated using two model biosensing assays, DNA target capture from complete bovine serum and from salmon genomic DNA mixtures. SPR results demonstrate that OEG incorporation into the ssDNA adlayer improves surface resistance to both nonspecific DNA and protein

  5. Hierarchical statistical analysis of complex analog and mixed-signal systems

    NASA Astrophysics Data System (ADS)

    Webb, Matthew; Tang, Hua

    2014-12-01

    With increasing process parameter variations in nanometre regime, circuits and systems encounter significant performance variations and therefore statistical analysis has become increasingly important. For complex analog and mixed-signal circuits and systems, efficient yet accurate statistical analysis has been a challenge mainly due to significant simulation and modelling time. In the past years, there have been various approaches proposed for statistical analysis of analog and mixed-signal circuits. A recent work is reported to address statistical analysis for continuous-time Delta-Sigma modulators. In this article, we generalise that method and present a hierarchical method for efficient statistical analysis of complex analog and mixed-signal circuits while maintaining reasonable accuracy. At circuit level, we use the response surface modelling method to extract quadratic models of circuit-level performance parameters in terms of process parameters. Then at system level, we use behavioural models and apply the Monte-Carlo method for statistical evaluation of system performance parameters. We illustrate and validate the method on a continuous-time Delta-Sigma modulator and an analog filter.

  6. Recharge mixing in a complex distributary spring system in the Missouri Ozarks, USA

    NASA Astrophysics Data System (ADS)

    Miller, Benjamin V.; Lerch, Robert N.; Groves, Christopher G.; Polk, Jason S.

    2015-05-01

    Toronto Springs is a complex distributary karst spring system with 11 perennial springs in the Missouri Ozarks, USA. Carroll Cave (CC) and Wet Glaize Creek (WG) were previously identified as principal recharge sources. This study (1) characterized physical and chemical properties of springs and recharge sources; (2) developed end-member mixing models to estimate contributing proportions of CC and WG; and (3) created a conceptual model for the system. Samples analyzed for major ions and specific conductivity, in conjunction with a rotating continuous monitoring program to identify statistically comparable baseflow conditions, were used to assess differences among the sites. Monitoring data showed that the springs differed depending upon recharge proportions. Cluster analysis of average ion concentrations supported the choice of CC and WG as mixing model end members. Results showed a range in the proportions of the recharge sources, from surface-water to groundwater dominated. A conceptual model suggests that a system of distinct conduits beneath the WG flood plain transmits water to the individual springs. These conduits controlled the end-member recharge contributions and water chemistry of the springs. Interpretation of relative proportions of recharge contributions extends existing knowledge of karst hydrologic geometry beyond that of point-to-point connections to revealing complex surface-water/groundwater mixing in heterogeneous distributary spring systems.

  7. Optoelectronic Properties of Color-Tunable Mixed Ligand-Based Light-Emitting Zinc Complexes

    NASA Astrophysics Data System (ADS)

    Singh, Devender; Bhagwan, Shri; Saini, Raman Kumar; Tanwar, Vijeta; Nishal, Vandna

    2016-10-01

    A series of mixed ligand-based zinc complexes (Zn1-Zn5); [(8-hydroxyquinolinato)(2-(2-hydroxyphenyl)benzimidazolato)zinc(II)] (Zn1), [(5-chloro-8-hydroxyquinolinato)(2-(2-hydroxyphenyl)benzimidazolato)zinc(II)] (Zn2), [(5,7-dichloro-8-hydroxyquinolinato)(2-(2-hydroxyphenyl)benzimidazolato)zinc(II)] (Zn3), [(2-methyl-8-hydroxyquinolinato)(2-(2-hydroxyphenyl)benzimidazolato)zinc(II)] (Zn4) and [(5,7-dimethyl-8-hydroxyquinolinato)(2-(2-hydroxyphenyl)benzimidazolato)zinc(II)] (Zn5) were synthesized and characterized. The photophysical properties of zinc complexes were examined by ultraviolet-visible absorption and photoluminescence emission spectroscopy. All prepared metal complexes produced intense luminescence on excitation with a UV light source. In this study, the color-tunable characteristics of metal complexes were investigated by introducing the electron-donating and electron-withdrawing groups on the 8-hydroxyquinoline ligand. The emission spectra of metal complexes showed emission wavelength at 500 nm for [ZnHBI(q)], 509 nm for [ZnHBI(Clq)], 504 nm for [Zn(HBI)(Cl2q)], 496 nm for [ZnHBI (Meq)] and 573 nm for [ZnHBI(Me2Q)] materials. A temperature-dependent PL spectrum was used to study the emission profile of zinc complex and observed that variation in the temperature altered the position and the intensity of emission peak. The synthesized metal complex also exhibited good thermal stability (>300°C). Photophysical characteristics of color-tunable light-emitting zinc complexes suggested that these materials could be efficiently used for emissive display device applications.

  8. Complex-path prediction of resonance-assisted tunneling in mixed systems.

    PubMed

    Fritzsch, Felix; Bäcker, Arnd; Ketzmerick, Roland; Mertig, Normann

    2017-02-01

    We present a semiclassical prediction of regular-to-chaotic tunneling in systems with a mixed phase space, including the effect of a nonlinear resonance chain. We identify complex paths for direct and resonance-assisted tunneling in the phase space of an integrable approximation with one nonlinear resonance chain. We evaluate the resonance-assisted contribution analytically and give a prediction based on just a few properties of the classical phase space. For the standard map excellent agreement with numerically determined tunneling rates is observed. The results should similarly apply to ionization rates and quality factors.

  9. Mixed outer synchronization of coupled complex networks with time-varying coupling delay.

    PubMed

    Wang, Jun-Wei; Ma, Qinghua; Zeng, Li; Abd-Elouahab, Mohammed Salah

    2011-03-01

    In this paper, the problem of outer synchronization between two complex networks with the same topological structure and time-varying coupling delay is investigated. In particular, we introduce a new type of outer synchronization behavior, i.e., mixed outer synchronization (MOS), in which different state variables of the corresponding nodes can evolve into complete synchronization, antisynchronization, and even amplitude death simultaneously for an appropriate choice of the scaling matrix. A novel nonfragile linear state feedback controller is designed to realize the MOS between two networks and proved analytically by using Lyapunov-Krasovskii stability theory. Finally, numerical simulations are provided to demonstrate the feasibility and efficacy of our proposed control approach.

  10. Prediction of Traffic Complexity and Controller Workload in Mixed Equipage NextGen Environments

    NASA Technical Reports Server (NTRS)

    Lee, Paul U.; Prevot, Thomas

    2012-01-01

    Controller workload is a key factor in limiting en route air traffic capacity. Past efforts to quantify and predict workload have resulted in identifying objective metrics that correlate well with subjective workload ratings during current air traffic control operations. Although these metrics provide a reasonable statistical fit to existing data, they do not provide a good mechanism for estimating controller workload for future air traffic concepts and environments that make different assumptions about automation, enabling technologies, and controller tasks. One such future environment is characterized by en route airspace with a mixture of aircraft equipped with and without Data Communications (Data Comm). In this environment, aircraft with Data Comm will impact controller workload less than aircraft requiring voice communication, altering the close correlation between aircraft count and controller workload that exists in current air traffic operations. This paper outlines a new trajectory-based complexity (TBX) calculation that was presented to controllers during a human-in-the-loop simulation. The results showed that TBX accurately estimated the workload in a mixed Data Comm equipage environment and the resulting complexity values were understood and readily interpreted by the controllers. The complexity was represented as a "modified aircraft account" that weighted different complexity factors and summed them in such a way that the controllers could effectively treat them as aircraft count. The factors were also relatively easy to tune without an extensive data set. The results showed that the TBX approach is well suited for presenting traffic complexity in future air traffic environments.

  11. Modeling mixed boundary conditions in a Hilbert space with the complex variable boundary element method (CVBEM).

    PubMed

    Johnson, Anthony N; Hromadka, T V

    2015-01-01

    The Laplace equation that results from specifying either the normal or tangential force equilibrium equation in terms of the warping functions or its conjugate can be modeled as a complex variable boundary element method or CVBEM mixed boundary problem. The CVBEM is a well-known numerical technique that can provide solutions to potential value problems in two or more dimensions by the use of an approximation function that is derived from the Cauchy Integral in complex analysis. This paper highlights three customizations to the technique.•A least squares approach to modeling the complex-valued approximation function will be compared and analyzed to determine if modeling error on the boundary can be reduced without the need to find and evaluated additional linearly independent complex functions.•The nodal point locations will be moved outside the problem domain.•Contour and streamline plots representing the warping function and its complementary conjugate are generated simultaneously from the complex-valued approximating function.

  12. Modeling mixed boundary conditions in a Hilbert space with the complex variable boundary element method (CVBEM)

    PubMed Central

    Johnson, Anthony N.; Hromadka, T.V.

    2015-01-01

    The Laplace equation that results from specifying either the normal or tangential force equilibrium equation in terms of the warping functions or its conjugate can be modeled as a complex variable boundary element method or CVBEM mixed boundary problem. The CVBEM is a well-known numerical technique that can provide solutions to potential value problems in two or more dimensions by the use of an approximation function that is derived from the Cauchy Integral in complex analysis. This paper highlights three customizations to the technique.•A least squares approach to modeling the complex-valued approximation function will be compared and analyzed to determine if modeling error on the boundary can be reduced without the need to find and evaluated additional linearly independent complex functions.•The nodal point locations will be moved outside the problem domain.•Contour and streamline plots representing the warping function and its complementary conjugate are generated simultaneously from the complex-valued approximating function. PMID:26151000

  13. Synthesis, characterization and biological activities of mixed ligand Zr(IV) complexes.

    PubMed

    Malghe, Yuvraj S; Prabhu, Rakesh C; Raut, Rajesh W

    2009-01-01

    Mixed ligand ternary Zr(IV) complexes of type [M(Q)2LNO3xH2O] have been synthesized using 8-hydroxyquinoline (HQ) as a primary ligand and N- and/O-donor amino acids (HL) such as L-serine, L-alanine and glycine as secondary ligands. These complexes were characterized on the basis of elemental analysis, conductance measurement, spectral and thermal studies. The molar conductance study of the complexes in DMF solvent signifies their non-electrolytic nature whereas the thermal analyses specify presence of a coordinated water molecule. The complexes were tested for antifungal and antibacterial activity by using agar well diffusion bioassay. The antibacterial activity was tested against the pathogenic bacteria Staphylococcus aureus and Enterococcus faecium. The results obtained were evaluated with antibacterial standard vancomycin. The antifungal activity was tested against Candida albicans, Candida krusei, Aspergillus fumigatus and the results obtained were compared with antifungal standard amphotericin B. The complexes were also screened for cytotoxicity studies against Ehrlich ascites cells and Daltons lymphoma ascites cells and show very low cytotoxicity.

  14. Synthesis, structural elucidation, biological, antioxidant and nuclease activities of some 5-Fluorouracil-amino acid mixed ligand complexes

    NASA Astrophysics Data System (ADS)

    Shobana, Sutha; Subramaniam, Perumal; Mitu, Liviu; Dharmaraja, Jeyaprakash; Arvind Narayan, Sundaram

    2015-01-01

    Some biologically active mixed ligand complexes (1-9) have been synthesized from 5-Fluorouracil (5-FU; A) and amino acids (B) such as glycine (gly), L-alanine (ala) and L-valine (val) with Ni(II), Cu(II) and Zn(II) ions. The synthesized mixed ligand complexes (1-9) were characterized by various physico-chemical, spectral, thermal and morphological studies. 5-Fluorouracil and its mixed ligand complexes have been tested for their in vitro biological activities against some pathogenic bacterial and fungal species by the agar well diffusion method. The in vitro antioxidant activities of 5-Fluorouracil and its complexes have also been investigated by using the DPPH assay method. The results demonstrate that Cu(II) mixed ligand complexes (4-6) exhibit potent biological as well as antioxidant activities compared to 5-Fluorouracil and Ni(II) (1-3) and Zn(II) (7-9) mixed ligand complexes. Further, the cleaving activities of CT DNA under aerobic conditions show moderate activity with the synthesized Cu(II) and Ni(II) mixed ligand complexes (1-6) while no activity is seen with Zn(II) complexes (7-9). Binding studies of CT DNA with these complexes show a decrease in intensity of the charge transfer band to the extent of 5-15% along with a minor red shift. The free energy change values (Δ‡G) calculated from intrinsic binding constants indicate that the interaction between mixed ligand complex and DNA is spontaneous.

  15. Synthesis, structural elucidation, biological, antioxidant and nuclease activities of some 5-Fluorouracil-amino acid mixed ligand complexes.

    PubMed

    Shobana, Sutha; Subramaniam, Perumal; Mitu, Liviu; Dharmaraja, Jeyaprakash; Arvind Narayan, Sundaram

    2015-01-05

    Some biologically active mixed ligand complexes (1-9) have been synthesized from 5-Fluorouracil (5-FU; A) and amino acids (B) such as glycine (gly), L-alanine (ala) and L-valine (val) with Ni(II), Cu(II) and Zn(II) ions. The synthesized mixed ligand complexes (1-9) were characterized by various physico-chemical, spectral, thermal and morphological studies. 5-Fluorouracil and its mixed ligand complexes have been tested for their in vitro biological activities against some pathogenic bacterial and fungal species by the agar well diffusion method. The in vitro antioxidant activities of 5-Fluorouracil and its complexes have also been investigated by using the DPPH assay method. The results demonstrate that Cu(II) mixed ligand complexes (4-6) exhibit potent biological as well as antioxidant activities compared to 5-Fluorouracil and Ni(II) (1-3) and Zn(II) (7-9) mixed ligand complexes. Further, the cleaving activities of CT DNA under aerobic conditions show moderate activity with the synthesized Cu(II) and Ni(II) mixed ligand complexes (1-6) while no activity is seen with Zn(II) complexes (7-9). Binding studies of CT DNA with these complexes show a decrease in intensity of the charge transfer band to the extent of 5-15% along with a minor red shift. The free energy change values (Δ(‡)G) calculated from intrinsic binding constants indicate that the interaction between mixed ligand complex and DNA is spontaneous.

  16. Microwave photonic notch filter with complex coefficient based on four wave mixing

    NASA Astrophysics Data System (ADS)

    Xu, Dong; Cao, Ye; Tong, Zheng-rong; Yang, Jing-peng

    2016-11-01

    A microwave photonic notch filter with a complex coefficient is proposed and demonstrated based on four wave mixing (FWM). FWM effect of two single-frequency laser beams occurs in a highly nonlinear fiber (HNLF), and multi-wavelength optical signals are generated and used to generate the multi-tap of microwave photonic filter (MPF). The complex coefficient is generated by using a Fourier-domain optical processor (FD-OP) to control the amplitude and phase of the optical carrier and phase modulation sidebands. The results show that this filter can be changed from bandpass filter to notch filter by controlling the FD-OP. The center frequency of the notch filter can be continuously tuned from 5.853 GHz to 29.311 GHz with free spectral range ( FSR) of 11.729 GHz. The shape of the frequency response keeps unchanged when the phase is tuned.

  17. B Plant complex hazardous, mixed and low level waste certification plan

    SciTech Connect

    Beam, T.G.

    1994-11-01

    This plan describes the administrative steps and handling methodology for certification of hazardous waste, mixed waste, and low level waste generated at B Plant Complex. The plan also provides the applicable elements of waste reduction and pollution prevention, including up front minimization and end product reduction of volume and/or toxicity. The plan is written to satisfy requirements for Hanford Site waste generators to have a waste certification program in place at their facility. This plan, as described, applies only to waste which is generated at, or is the responsibility of, B Plant Complex. The scope of this plan is derived from the requirements found in WHC-EP-0063, Hanford Site Solid Waste Acceptance Criteria.

  18. Bis- and Tetrakis(carboxylato)platinum(IV) complexes with mixed axial ligands - synthesis, characterization, and cytotoxicity.

    PubMed

    Hoffmeister, Björn R; Hejl, Michaela; Adib-Razavi, Mahsa S; Jakupec, Michael A; Galanski, Markus; Keppler, Bernhard K

    2015-04-01

    A series of twelve novel diamminetetrakis(carboxylato)platinum(IV) and 18 novel bis(carboxylato)dichlorido(ethane-1,2-diamine)platinum(IV) complexes with mixed axial carboxylato ligands was synthesized and characterized by multinuclear (1) H-, (13) C-, (15) N-, and (195) Pt-NMR spectroscopy. Their cytotoxic potential was evaluated (by MTT assay) against three human cancer cell lines derived from ovarian teratocarcinoma (CH1/PA-1), lung (A549), and colon carcinoma (SW480). In the cisplatin-sensitive CH1/PA-1 cancer cell line, diamminetetrakis(carboxylato)platinum(IV) complexes showed IC50 values in the low micromolar range, whereas, for the most lipophilic compounds of the bis(carboxylato)dichlorido(ethane-1,2-diamine)platinum(IV) series, IC50 values in the nanomolar range were found. Copyright © 2015 Verlag Helvetica Chimica Acta AG, Zürich.

  19. Hydrogen activation by unsaturated mixed-metal cluster complexes: new directions.

    PubMed

    Adams, Richard D; Captain, Burjor

    2008-01-01

    There has been a renewed interest in the chemistry of hydrogen as a result of the ever-increasing global demands for energy. Recent studies have revealed new electronically unsaturated polynuclear metal complexes containing bulky ligands that exhibit a variety of reactions with hydrogen, including facile addition and elimination under mild conditions. Materials and molecules that can reversibly absorb large quantities of hydrogen are very attractive for hydrogen storage and hydrogenation catalysis. This Minireview summarizes recent studies of reactions of hydrogen with unsaturated mixed-metal cluster complexes containing platinum and bulky phosphine ligands. Some related studies on bimetallic cooperativity and the synthesis of trimetallic nanoparticles on mesoporous supports that exhibit high activity and selectivity for catalytic hydrogenations are also discussed.

  20. Organic nanostructures with controllable morphology fabricated from mixed (phthalocyaninato)(porphyrinato) europium double-decker complexes.

    PubMed

    Zhang, Xiaomei; Wang, Quanbo; Wu, Lizhen; Lv, Wei; Lu, Jitao; Bian, Yongzhong; Jiang, Jianzhuang

    2010-01-28

    The self-assembly behavior of two sandwich-type mixed (phthalocyaninato)(porphyrinato) europium double-decker complexes, namely Eu(Pc)(TClPP) [Pc = phthalocyaninate; TClPP = meso-tetrakis(4-chlorophenyl)porphyrinate] (1) and optically active (R)- and (S)-EuH[Pc(OBNP)(2)](TClPP)] [Pc(OBNP)(2) = phthalocyaninate with two aromatic chiral binaphthayl units attached at the nonperipheral positions] (2), has been comparatively studied. In addition, a hydrophilic additive with intense adhesive ability, sodium carboxymethylcellulose (CMC), was also introduced onto the sandwich-type self-assembly systems to combine with double-decker molecules to induce additional hydrophilic/hydrophobic interaction. In the absence of the additive CMC, the double-decker molecules of 1 self-assemble into nanobelts in mixed solvent of chloroform and methanol. Introduction of two aromatic chiral binaphthayl units onto the nonperipheral positions of phthalocyanine ligand in the sandwich-type mixed double-decker complex 2 leads to the formation of tubal nanostructures. Observation of significant difference in the circular dichroism (CD) spectra of (R)- and (S)-2 in chloroform from their aggregates dispersed in methanol confirms the effective intermolecular interaction due to the interplay of pi-pi interaction between adjacent double-decker molecules with chiral discrimination among chiral side chains at supramolecular level. With addition of CMC, cooperation of intrinsic intermolecular pi-pi interaction with additionally introduced hydrophilic/hydrophobic interaction between adjacent double-decker molecules induces the formation of nanoscale hollow spheres at 45 degrees C during the self-assembly process of 1 and 2.

  1. X-ray absorption spectral studies of copper (II) mixed ligand complexes

    NASA Astrophysics Data System (ADS)

    Soni, B.; Dar, Davood Ah; Shrivastava, B. D.; Prasad, J.; Srivastava, K.

    2014-09-01

    X-ray absorption spectra at the K-edge of copper have been studied in two copper mixed ligand complexes, one having tetramethyethylenediamine (tmen) and the other having tetraethyethylenediamine (teen) as one of the ligands. The spectra have been recorded at BL-8 dispersive extended X-ray absorption fine structure (EXAFS) beamline at the 2.5 GeV INDUS- 2 synchrotron, RRCAT, Indore, India. The data obtained has been processed using the data analysis program Athena. The energy of the K-absorption edge, chemical shift, edge-width and shift of the principal absorption maximum in the complexes have been determined and discussed. The values of these parameters have been found to be approximately the same in both the complexes indicating that the two complexes possess similar chemical environment around the copper metal atom. The chemical shift has been utilized to estimate effective nuclear charge on the absorbing atom. The normalized EXAFS spectra have been Fourier transformed. The position of the first peak in the Fourier transform gives the value of first shell bond length, which is shorter than the actual bond length because of energy dependence of the phase factors in the sine function of the EXAFS equation. This distance is thus the phase- uncorrected bond length. Bond length has also been determined by Levy's, Lytle's and Lytle, Sayers and Stern's (LSS) methods. The results obtained from LSS and the Fourier transformation methods are comparable with each other, since both are phase uncorrected bond lengths.

  2. Mixed complexes of palladium(II) with 1-aminoethylidene-1,1-diphosphonic acid and glycine

    NASA Astrophysics Data System (ADS)

    Kozachkova, A. N.; Tsaryk, N. V.; Dudko, A. V.; Pekhnyo, V. I.; Trachevsky, V. V.; Rozhenko, A. B.; Novotortsev, V. M.; Eremenko, I. L.

    2012-10-01

    The complexing of palladium(II) with two biological active reagents: glycine (Gly, HA) and 1-aminoethylidene-1,1-diphosphonic acid (AEDP, H4L) at concentrations of chloride ions (0.15 mol/L) corresponding to physiological levels is studied by means of spectrophotometry, pH potentiometry, and 31P NMR spectroscopy. The formation constants for mixed complexes with compositions of [PdH2LA]- (logβ = 43.7) and [PdHLA]2- (logβ = 39.05) are determined. The both ligands are found to be coordinated to palladium(II) in a bidentant-cyclic manner: through amine nitrogen and the oxygen atom of the carboxyl group (in the case of Gly), or through the phosphonic group (in the case of AEDP). A diagram of the distribution of equilibrium concentrations of the complexes depending on pH is calculated for the system K2[PdCl4]: Gly: AEDP = 1: 1: 1. It is demonstrated that there are complexes with compositions of [PdHLA]2-, [PdA2], and [Pd(HL)2]4- in solutions with C_{Cl^ - } = 0.15 mol/L and pH 6-7.

  3. Design of vanadium mixed-ligand complexes as potential anti-protozoa agents.

    PubMed

    Benítez, Julio; Guggeri, Lucía; Tomaz, Isabel; Arrambide, Gabriel; Navarro, Maribel; Pessoa, João Costa; Garat, Beatriz; Gambino, Dinorah

    2009-04-01

    In the search for new therapeutic tools against Chagas' disease (American Trypanosomiasis) four novel mixed-ligand vanadyl complexes, [V(IV)O(L(2)-2H)(L(1))], including a bidentate polypyridyl DNA intercalator (L(1)) and a tridentate salycylaldehyde semicarbazone derivative (L(2)) as ligands were synthesized, characterized by a combination of techniques, and in vitro evaluated. EPR suggest a distorted octahedral geometry with the tridentate semicarbazone occupying three equatorial positions and the polypyridyl ligand coordinated in an equatorial/axial mode. Both complexes including dipyrido[3,2-a: 2',3'-c]phenazine (dppz) as polypyridyl coligand showed IC(50) values in the muM range against Dm28c strain (epimastigotes) of Trypanosoma cruzi, causative agent of the disease, being as active as the anti-trypanosomal reference drug Nifurtimox. To get an insight into the trypanocidal mechanism of action of these compounds, DNA was evaluated as a potential parasite target and EPR, and (51)V NMR experiments were also carried out upon aging aerated solutions of the complexes. Data obtained by electrophoretic analysis suggest that the mechanism of action of these complexes could include DNA interactions.

  4. Group 13 and lanthanide complexes with mixed O,S anionic ligands derived from maltol.

    PubMed

    Monga, Vishakha; Patrick, Brian O; Orvig, Chris

    2005-04-18

    Four mixed O,S binding ligand precursors derived from maltol (3-hydroxy-2-methyl-4-pyrone) have been chelated to gallium(III), indium(III), and lanthanide(III) ions to yield a series of metal complexes. The four ligand precursors include two pyranthiones, 3-hydroxy-2-methyl-4-pyranthione, commonly known as thiomaltol (Htma), and 2-ethyl-3-hydroxy-4-pyranthione, commonly known as ethylthiomaltol (Hetma), and two pyridinethiones, 3-hydroxy-2-methyl-4(H)-pyridinethione (Hmppt) and 3-hydroxy-1,2-dimethyl-4-pyridinethione (Hdppt). Dimeric forms of the pyridinethiones, Hmppt dimer and Hdppt dimer, were also isolated and characterized. Complete characterization of the monomeric organic compounds is reported including acidity constants and crystal structures of Htma, Hetma, and Hdppt dimer. Reacting the four monomeric ligand precursors with Ga(3+) and In(3+) ions yielded new tris(bidentate ligand) complexes. X-ray-quality crystals of the fac isomer of Ga(tma)(3) were also obtained. New complexes with a range of lanthanides (Ln(3+)) were also synthesized with the two pyranthiones, Htma and Hetma. The synthesis reactions yielded complexes of the type LnL(3).xH(2)O and LnL(2)(OH).xH(2)O, as indicated by elemental analysis and spectroscopic evidence such as mass spectral data and IR and NMR spectra.

  5. Organometallic Iridium Complex Containing a Dianionic, Tridentate, Mixed Organic-Inorganic Ligand.

    PubMed

    Bloomfield, Aaron J; Matula, Adam J; Mercado, Brandon Q; Batista, Victor S; Crabtree, Robert H

    2016-08-15

    A pentamethylcyclopentadienyl-iridium complex containing a tricyclic, dianionic, tridentate, scorpionate (facial binding), mixed organic-inorganic ligand was synthesized and characterized by single-crystal X-ray crystallography, as well as polynuclear NMR, UV-vis, and IR spectroscopies. The central cycle of the tridentate ligand consists of a modified boroxine in which two of the boron centers are tetrahedral, anionic borates. The complex is stable to hydrolysis in aqueous solution for >9 weeks at 25 °C but reacts with a 50 mM solution of sodium periodate within 12 s to form a periodate-driven oxygen evolution catalyst that has a turnover frquency of >15 s(-1). However, the catalyst is almost completely deactivated within 5 min, achieving an average turnover number of ca. 2500 molecules of oxygen per atom of iridium. Nanoparticles were not observed on this time scale but did form within 4 h of catalyst activation under these experimental conditions. The parent complex was modeled using density functional theory, which accurately reflected the geometry of the complex and indicated significant interaction of iridium- and boracycle-centered orbitals.

  6. Mixed-complexity artificial grammar learning in humans and macaque monkeys: evaluating learning strategies.

    PubMed

    Wilson, Benjamin; Smith, Kenny; Petkov, Christopher I

    2015-03-01

    Artificial grammars (AG) can be used to generate rule-based sequences of stimuli. Some of these can be used to investigate sequence-processing computations in non-human animals that might be related to, but not unique to, human language. Previous AG learning studies in non-human animals have used different AGs to separately test for specific sequence-processing abilities. However, given that natural language and certain animal communication systems (in particular, song) have multiple levels of complexity, mixed-complexity AGs are needed to simultaneously evaluate sensitivity to the different features of the AG. Here, we tested humans and Rhesus macaques using a mixed-complexity auditory AG, containing both adjacent (local) and non-adjacent (longer-distance) relationships. Following exposure to exemplary sequences generated by the AG, humans and macaques were individually tested with sequences that were either consistent with the AG or violated specific adjacent or non-adjacent relationships. We observed a considerable level of cross-species correspondence in the sensitivity of both humans and macaques to the adjacent AG relationships and to the statistical properties of the sequences. We found no significant sensitivity to the non-adjacent AG relationships in the macaques. A subset of humans was sensitive to this non-adjacent relationship, revealing interesting between- and within-species differences in AG learning strategies. The results suggest that humans and macaques are largely comparably sensitive to the adjacent AG relationships and their statistical properties. However, in the presence of multiple cues to grammaticality, the non-adjacent relationships are less salient to the macaques and many of the humans.

  7. Novel dinuclear platinum(II) complexes containing mixed nitrogen-sulfur donor ligands.

    PubMed

    Hochreuther, Stephanie; Puchta, Ralph; van Eldik, Rudi

    2011-12-19

    A series of novel dinuclear platinum(II) complexes were synthesized containing a mixed nitrogen-sulfur donor bidentate chelate system in which the two platinum centers are connected by an aliphatic chain of variable length. The bidentate chelating ligands were selected to stabilize the complex toward decomposition. The pK(a) values and reactivity of the four synthesized complexes, namely, [Pt(2)(S(1),S(4)-bis(2-pyridylmethyl)-1,4-butanedithioether)(OH(2))(4)](4+) (4NSpy), [Pt(2)(S(1),S(6)-bis(2-pyridylmethyl)-1,6-hexanedithioether)(OH(2))(4)](4+) (6NSpy), [Pt(2)(S(1),S(8)-bis(2-pyridylmethyl)-1,8-octanedithioether)(OH(2))(4)](4+) (8NSpy), and [Pt(2)(S(1),S(10)-bis(2-pyridylmethyl)-1,10-decanedithioether)(OH(2))(4)](4+) (10NSpy), were investigated. This system is of special interest because only little is known about the substitution behavior of dinuclear platinum complexes that contain a bidentate chelate that forms part of the aliphatic bridging ligand. Moreover, the ligands as well as the dinuclear complexes were examined in terms of their cytotoxic activity, and the 10NSpy complex was found to be active. Spectrophotometric acid-base titrations were performed to determine the pK(a) values of all the coordinated water molecules. The substitution of coordinated water by thiourea was studied under pseudo-first-order conditions as a function of nucleophile concentration, temperature, and pressure, using stopped-flow techniques and UV-vis spectroscopy. The results for the dinuclear complexes were compared to those for the corresponding mononuclear reference complex [Pt(methylthiomethylpyridine)(OH(2))(2)](2+) (Pt(mtp)), by which the effect of the increasing aliphatic chain length of the bridged complexes could be investigated. The results indicate that there is a clear interaction between the two platinum centers, which becomes weaker as the chain length between the metal centers increases. Furthermore, differences and similarities of the N,S-system were compared to

  8. Unusual structures and reactivity of mixed metal cluster complexes containing the palladium/platinum tri-t-butylphosphine grouping.

    PubMed

    Adams, Richard D; Captain, Burjor

    2009-03-17

    Polynuclear metal carbonyl complexes have a range of applications in chemical research: for example, they can serve as surface models to probe features of heterogeneous catalysis and can perform novel transformations of organic molecules in solutions. Mixed metal complexes can demonstrate bimetallic cooperativity and synergism and can also serve as precursors to multimetallic heterogeneous catalysts that have superior activities and selectivities. This Account describes the results of our recent comprehensive study of the chemistry of mixed metal cluster complexes containing the sterically encumbered M(PBu(t)(3)), M = Pd or Pt, group. This grouping readily adds to the metal-metal bonds of metal carbonyl cluster complexes and modifies their reactivity. We have prepared new, highly electronically unsaturated mixed metal complexes that exhibit unusually high reactivity toward hydrogen. The platinum atom of the Pt(PBu(t)(3)) grouping can bond to as many as five metal atoms, and it can interconvert, sometimes rapidly, between the different bonding modes. The large steric effects of the PBu(t)(3) ligand allowed us to prepare highly unsaturated, stable, mixed-metal complexes, and these complexes react with hydrogen, sometimes reversibly, under very mild conditions to yield polyhydride complexes. Strong evidence suggests that the Pt(PBu(t)(3)) group can also activate metal-hydrogen bonds in other complexes. In the future, we expect that researchers will prepare a greater variety of mixed metal complexes containing the Pd/Pt(PBu(t)(3)) group or other similar bulky groups, and that some of these complexes will exhibit even more unusual chemistry than what we have observed so far.

  9. Modulating the morphology of hydrogel particles by thermal annealing: mixed biopolymer electrostatic complexes

    NASA Astrophysics Data System (ADS)

    Wu, Bi-cheng; McClements, David Julian

    2015-11-01

    Biopolymer hydrogel particles formed by electrostatic complexation of proteins and polysaccharides have various applications within the food and other industries, including as delivery systems for bioactive compounds, as texture modifiers, and as fat replacers. The functional attributes of these electrostatic complexes are strongly influenced by their morphology, which is determined by the molecular interactions between the biopolymer molecules. In this study, electrostatic complexes were formed using an amphoteric protein (gelatin) and an anionic polysaccharide (pectin). Gelatin undergoes a helix-to-coil transition when heated above a critical temperature, which impacts its molecular interactions and hydrogel formation. The aim of this research was to study the influence of thermal annealing on the properties of hydrogel particles formed by electrostatic complexation of gelatin and pectin. Hydrogel particles were fabricated by mixing 0.5 wt% gelatin and 0.01 wt% pectin at pH 10 (where both were negatively charged) at various temperatures, followed by acidification to pH 5 (where they have opposite charges) with controlled acidification and stirring. The gelation ({{T}\\text{g}} ) and melting temperature ({{T}\\text{m}} ) of the electrostatic complexes were measuring using a small amplitude oscillation test: {{T}\\text{g}}=26.3 °C and {{T}\\text{m}}=32.3 °C. Three annealing temperatures (5, 30 and 50 °C) corresponding to different regimes (T<{{T}\\text{g}} , {{T}\\text{g}}\\text{m}} , and T>{{T}\\text{m}} ) were selected to control the configuration of the gelatin chain. The effects of formation temperature, annealing temperature, and incubation time on the morphology of the hydrogel particles were characterized by turbidity, static light scattering, and microscopy. The results of this study will facilitate the rational design of hydrogel particles with specific particle dimensions and morphologies, which has important implications for tailoring their

  10. Copper(ii) mixed-ligand polypyridyl complexes with doxycycline - structures and biological evaluation.

    PubMed

    Abosede, Olufunso O; Vyas, Nilima A; Singh, Sushma B; Kumbhar, Avinash S; Kate, Anup; Kumbhar, Anupa A; Khan, Ayesha; Erxleben, Andrea; Smith, Peter; de Kock, Carmen; Hoffmann, Frank; Obaleye, Joshua A

    2016-02-21

    Mixed-ligand Cu(ii) complexes of the type [Cu(doxycycline)(L)(H2O)2](NO3)2, where doxycycline = [4-(dimethylamino)-3,5,10,12,12a-pentahydroxy-6-methyl-1,11-dioxo-1,4,4a,5,5a,6,11,12a-octahydrotetracene-2-carboxamide] and L = 2,2'-bipyridine (bpy, 1), 1,10-phenanthroline (phen, 2), dipyrido[3,2-d:2',3'-f]quinoxaline (dpq, 3) and dipyrido[3,2-a:2',3'-c]phenazine (dppz, 4) have been synthesised and characterised by structural, analytical, and spectral methods. The single-crystal X-ray structures of 1 and 2 exhibited two different geometries, distorted square-pyramidal and octahedral respectively as well as different coordination modes of doxycycline. Complexes 2-4 exhibit prominent plasmid DNA cleavage at significantly low concentrations probably by an oxidative mechanism. Matrix Metalloproteinase (MMP-2) inhibition studies revealed that all complexes inhibit MMP-2 similar to doxycycline which is a well-known MMP inhibitor with 3 being the most potent. IC50 values of doxycycline and 1-4 against MCF-7 (human breast cancer) and HeLa cell lines were almost equal in which 3 showed the highest efficiency (IC50 = 0.46 ± 0.05 μM), being consistent with its increased MMP inhibition potency. The antimalarial activities of these complexes against the chloroquine-sensitive Plasmodium falciparum NF54 and chloroquine-resistant Plasmodium falciparum Dd2 strains reveal that complex 3 exhibited a higher activity than artesunate drug against the chloroquine-resistant Dd2 strain.

  11. Mixed Linear Model Approaches of Association Mapping for Complex Traits Based on Omics Variants.

    PubMed

    Zhang, Fu-Tao; Zhu, Zhi-Hong; Tong, Xiao-Ran; Zhu, Zhi-Xiang; Qi, Ting; Zhu, Jun

    2015-07-30

    Precise prediction for genetic architecture of complex traits is impeded by the limited understanding on genetic effects of complex traits, especially on gene-by-gene (GxG) and gene-by-environment (GxE) interaction. In the past decades, an explosion of high throughput technologies enables omics studies at multiple levels (such as genomics, transcriptomics, proteomics, and metabolomics). The analyses of large omics data, especially two-loci interaction analysis, are very time intensive. Integrating the diverse omics data and environmental effects in the analyses also remain challenges. We proposed mixed linear model approaches using GPU (Graphic Processing Unit) computation to simultaneously dissect various genetic effects. Analyses can be performed for estimating genetic main effects, GxG epistasis effects, and GxE environment interaction effects on large-scale omics data for complex traits, and for estimating heritability of specific genetic effects. Both mouse data analyses and Monte Carlo simulations demonstrated that genetic effects and environment interaction effects could be unbiasedly estimated with high statistical power by using the proposed approaches.

  12. Mixed micelles loaded with silybin-polyene phosphatidylcholine complex improve drug solubility

    PubMed Central

    Duan, Rui-ling; Sun, Xun; Liu, Jie; Gong, Tao; Zhang, Zhi-rong

    2011-01-01

    Aim: To prepare a novel formulation of phosphatidylcholine (PC)-bile salts (BS)-mixed micelles (MMs) loaded with silybin (SLB)-PC complex for parenteral applications. Methods: SLB-PC-BS-MMs were prepared using the co-precipitation method. Differential scanning calorimetry (DSC) analysis was used to confirm the formation of the complex and several parameters were optimized to obtain a high quality formulation. The water-solubility, drug loading, particle size, zeta potential, morphology and in vivo properties of the SLB-PC-BS-MMs were determined. Results: The solubility of SLB in water was increased from 40.83±1.18 μg/mL to 10.14±0.36 mg/mL with a high drug loading (DL) of 14.43%±0.44% under optimized conditions. The SLB-PC-BS-MMs were observed by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) and showed spherical shapes. The particle size and zeta potential, as measured by photon correlation spectroscopy (PCS), were about 30±4.8 nm and −39±5.0 mV, respectively. In vivo studies showed that incorporation of the SLB-PC complex into PC-BS-MMs led to a prolonged circulation time of the drug. Conclusion: This novel formulation appears to be a good candidate for drug substances that exhibit poor solubility for parenteral administration. PMID:21170082

  13. A complex magma mixing origin for rocks erupted in 1915, Lassen Peak, California

    USGS Publications Warehouse

    Clynne, M.A.

    1999-01-01

    The eruption of Lassen Peak in May 1915 produced four volcanic rock types within 3 days, and in the following order: (1) hybrid black dacite lava containing (2) undercooled andesitic inclusions, (3) compositionally banded pumice with dark andesite and light dacite bands, and (4) unbanded light dacite. All types represent stages of a complex mixing process between basaltic andesite and dacite that was interrupted by the eruption. They contain disequilibrium phenocryst assemblages characterized by the co-existence of magnesian olivine and quartz and by reacted and unreacted phenocrysts derived from the dacite. The petrography and crystal chemistry of the phenocrysts and the variation in rock compositions indicate that basaltic andesite intruded dacite magma and partially hybridized with it. Phenocrysts from the dacite magma were reacted. Cooling, cyrstallization, and vesiculation of the hybrid andesite magma converted it to a layer of mafic foam. The decreased density of the andesite magma destabilized and disrupted the foam. Blobs of foam rose into and were further cooled by the overlying dacite magma, forming the andesitic inclusions. Disaggregation of andesitic inclusions in the host dacite produced the black dacite and light dacite magmas. Formation of foam was a dynamic process. Removal of foam propagated the foam layer downward into the hybrid andesite magma. Eventually the thermal and compositional contrasts between the hybrid andesite and black dacite magmas were reduced. Then, they mixed directly, forming the dark andesite magma. About 40-50% andesitic inclusions were disaggregated into the host dacite to produce the hybrid black dacite. Thus, disaggregation of inclusions into small fragments and individual crystals can be an efficient magma-mixing process. Disaggregation of undercooled inclusions carrying reacted host-magma phenocrysts produces co-existing reacted and unreacted phenocrysts populations.

  14. Calculation of equilibrium binding constants and cooperativity of Cu(II) mixed solvated complexes formation.

    PubMed

    Kudrev, A G

    2012-11-15

    A new extension of matrix approach is proposed to calculate the equilibrium constants of coordinated solvent substitution in a metal ion first salvation shell in the mixed solvent system. The proposed method allows reducing the number of independent variables, necessary to calculate the fractions of species in solution. The equilibrium model of MeCN substitution with DMF and DMSO in the presence of Cu(II) ion for the assessment of structure of intermediate species is presented and verified. The distribution diagrams of Cu(II) species in mixed organic solvents have been analyzed using the modified matrix method. The intrinsic equilibrium constants K of the first solvent molecule replacement in the Cu(II) coordination shell and the correction for the mutual influence between the solvent molecules as ligands in the successive complex formation (cooperativity parameter w) in acetonitrile solution have been calculated from the fitting procedure. It is shown that anticooperative substitution of MeCN by donor ligands in the first coordination shell of the Cu(II) ion is always governed by the change of coordination number during the stepwise process.

  15. Capturing complexity: Mixing methods in the analysis of a European tobacco control policy network

    PubMed Central

    Weishaar, Heide; Amos, Amanda; Collin, Jeff

    2015-01-01

    Social network analysis (SNA), a method which can be used to explore networks in various contexts, has received increasing attention. Drawing on the development of European smoke-free policy, this paper explores how a mixed method approach to SNA can be utilised to investigate a complex policy network. Textual data from public documents, consultation submissions and websites were extracted, converted and analysed using plagiarism detection software and quantitative network analysis, and qualitative data from public documents and 35 interviews were thematically analysed. While the quantitative analysis enabled understanding of the network's structure and components, the qualitative analysis provided in-depth information about specific actors' positions, relationships and interactions. The paper establishes that SNA is suited to empirically testing and analysing networks in EU policymaking. It contributes to methodological debates about the antagonism between qualitative and quantitative approaches and demonstrates that qualitative and quantitative network analysis can offer a powerful tool for policy analysis. PMID:26185482

  16. Capturing complexity: Mixing methods in the analysis of a European tobacco control policy network.

    PubMed

    Weishaar, Heide; Amos, Amanda; Collin, Jeff

    Social network analysis (SNA), a method which can be used to explore networks in various contexts, has received increasing attention. Drawing on the development of European smoke-free policy, this paper explores how a mixed method approach to SNA can be utilised to investigate a complex policy network. Textual data from public documents, consultation submissions and websites were extracted, converted and analysed using plagiarism detection software and quantitative network analysis, and qualitative data from public documents and 35 interviews were thematically analysed. While the quantitative analysis enabled understanding of the network's structure and components, the qualitative analysis provided in-depth information about specific actors' positions, relationships and interactions. The paper establishes that SNA is suited to empirically testing and analysing networks in EU policymaking. It contributes to methodological debates about the antagonism between qualitative and quantitative approaches and demonstrates that qualitative and quantitative network analysis can offer a powerful tool for policy analysis.

  17. [Component analysis of complex mixed solution based on multidimensional diffuse reflectance spectroscopy].

    PubMed

    Li, Gang; Xiong, Chan; Zhao, Li-ying; Lin, Ling; Tong, Ying; Zhang, Bao-ju

    2012-02-01

    In the present paper, the authors proposed a method for component analysis of complex mixed solutions based on multidimensional diffuse reflectance spectroscopy by analyzing the information carried by spectrum signals from various optical properties of various components of the analyte. The experiment instrument was designed with supercontinuum laser source, the motorized precision translation stage and the spectrometer. The Intralipid-20% was taken as an analyte, and was diluted over a range of 1%-20% in distilled water. The diffuse reflectance spectrum signal was measured at 24 points within the distance of 1.5-13 mm (at an interval of 0.5 mm) above the incidence point. The partial least squares algorithm model was used to perform a modeling and forecasting analysis for the spectral analysis data collected from single-point and multi-point. The results showed that the most accurate calibration model was created by the spectral data acquired from the nearest 1-13 points above the incident point; the most accurate prediction model was created by the spectral signal acquired from the nearest 1-7 points above the incident point. It was proved that multidimensional diffuse reflectance spectroscopy can improve the spectral signal to noise ratio. Compared with the traditional spectrum technology using a single optical property such as absorbance or reflectance, this method increased the impact of scattering characteristics of the analyte. So the use of a variety of optical properties of the analytes can make an improvement of the accuracy of the modeling and forecasting, and also provide a basis for component analysis of the complex mixed solution based on multidimensional diffuse reflectance spectroscopy.

  18. Multifunctional DNA interactions of Ru-Pt mixed metal supramolecular complexes with substituted terpyridine ligands.

    PubMed

    Jain, Avijita; Wang, Jing; Mashack, Emily R; Winkel, Brenda S J; Brewer, Karen J

    2009-10-05

    The coupling of a light absorbing unit to a bioactive site allows for the development of supramolecules with multifunctional interactions with DNA. A series of mixed metal supramolecular complexes that couple a DNA-binding cis-Pt(II)Cl(2) center to a ruthenium chromophore via a polyazine bridging ligand have been prepared, and their DNA interactions have been studied, [(TL)RuCl(dpp)PtCl(2)](PF(6)) (TL = tpy (2,2':6',2''-terpyridine), MePhtpy (4'-(4-methylphenyl)-2,2':6',2''-terpyridine), or (t)Bu(3)tpy (4,4',4''-tri-tert-butyl-2,2':6',2''-terpyridine and dpp = 2,3-bis(2-pyridyl)pyrazine). This series provides for unique tridentate coordinated Ru(II) systems to photocleave DNA with preassociation with the DNA target via coordination of the Pt(II) center. Electronic absorption spectroscopy of the complexes displays intense ligand-based pi-->pi* transitions in the UV region and metal to ligand charge transfer (MLCT) transitions in the visible region. The Ru(dpi)-->dpp(pi*) MLCT transitions occur at 545 nm, red-shifted relative to the 520 nm maxima for the monometallic synthons, [(TL)RuCl(dpp)](PF(6)). The title RuPt complexes display reversible Ru(II/III) oxidative couples at 1.10, 1.10, and 1.01 V vs Ag/AgCl for TL = tpy, MePhtpy, and (t)Bu(3)tpy, respectively. The TL(0/-) reduction occurred at -1.43, -1.44, and -1.59 V vs Ag/AgCl for TL = tpy, MePhtpy, and (t)Bu(3)tpy, respectively. These complexes display a dpp(0/-) couple (-0.50 -0.55, and -0.59 V) significantly shifted to positive potential relative to their monometallic synthons (-1.15, -1.16, and -1.22 V), consistent with the bridging coordination of the dpp ligand. Coupling of (TL)Ru(II)Cl(BL) subunit to a cis-Pt(II)Cl(2) site provides for the application of photochemically inactive Ru(II)(tpy)-based chromophores in DNA photocleavage applications. The [(TL)RuCl(dpp)PtCl(2)](+) complexes display covalent binding to DNA and photocleavage upon irradiation with visible light modulated by TL identity. The redox

  19. Geostatistical reservoir characterization of complex lateral and vertical sequences in a mixed carbonate platform

    SciTech Connect

    Norris, R.J.; Alabert, F.G.; Massonnat, G.J. )

    1994-07-01

    In recent years reservoir characterization through the use of geostatistics has become an almost routine part of production geology. Many techniques are available within the broad title of geostatistics, having been developed in response to many types of problem. One characteristic feature of almost all techniques (Stochastic Indicator Simulation, Boolean [open quotes]object[close quotes] Modeling, Gaussian [and Truncated Gaussian] methods and Optimized Markov-fields) is their reliance on the concept of quantifiable correlations, which reflect some aspect of the shape of [open quotes]objects.[close quotes] For example, almost any of the above noted techniques, and their variants, could be used to model fluvial, deltaic, or turbiditic reservoirs because in each case facies can be described in terms of geometries (channels, lobes, etc.). This study considers the complex lateral and vertical variations of a mixed carbonate platform environment, where facies cannot be easily characterized by simple geometries. The complex heterogeneities are a function of changes in sea level, representing fluctuations over several orders of cyclicity. Given facies have no characteristic form, being the product of the interplay between sediment supply and sea level change. This type of environment is, therefore, characterized by a good deal of information concerning trends in the data, while correlations and geometries are almost meaningless. Associated with the concepts of cyclicity, rules concerning the reappearance of facies, or otherwise, were developed. For example, minor recurrences of maximum flooding surfaces could be tolerated within individual units but other specified recurrences need to be excluded.

  20. Mixed-mode oscillations and population bursting in the pre-Bötzinger complex

    PubMed Central

    Bacak, Bartholomew J; Kim, Taegyo; Smith, Jeffrey C; Rubin, Jonathan E; Rybak, Ilya A

    2016-01-01

    This study focuses on computational and theoretical investigations of neuronal activity arising in the pre-Bötzinger complex (pre-BötC), a medullary region generating the inspiratory phase of breathing in mammals. A progressive increase of neuronal excitability in medullary slices containing the pre-BötC produces mixed-mode oscillations (MMOs) characterized by large amplitude population bursts alternating with a series of small amplitude bursts. Using two different computational models, we demonstrate that MMOs emerge within a heterogeneous excitatory neural network because of progressive neuronal recruitment and synchronization. The MMO pattern depends on the distributed neuronal excitability, the density and weights of network interconnections, and the cellular properties underlying endogenous bursting. Critically, the latter should provide a reduction of spiking frequency within neuronal bursts with increasing burst frequency and a dependence of the after-burst recovery period on burst amplitude. Our study highlights a novel mechanism by which heterogeneity naturally leads to complex dynamics in rhythmic neuronal populations. DOI: http://dx.doi.org/10.7554/eLife.13403.001 PMID:26974345

  1. Mixed amido-/imido-/guanidinato niobium complexes: synthesis and the effect of ligands on insertion reactions.

    PubMed

    Elorriaga, David; Carrillo-Hermosilla, Fernando; Antiñolo, Antonio; López-Solera, Isabel; Fernández-Galán, Rafael; Villaseñor, Elena

    2014-12-14

    The new monoguanidinato complexes [Nb(NMe2)2{N(2,6-(i)Pr2C6H3)}{(NR)(NR')C(NMe2)}] (R = R' = (i)Pr, 2; R = (t)Bu, R' = Et, 3) were obtained by the insertion reaction of either diisopropylcarbodiimide or 1-tert-butyl-3-ethylcarbodiimide with the triamido precursor [Nb(NMe2)3(N-2,6-(i)Pr2C6H3)] (1) bearing a bulky imido moiety. The μ-oxo derivative [{N(2,6-(i)Pr2C6H3)}{(N(i)Pr)2C(NMe2)}(NMe2)Nb]2(μ-O) (2a) was formed by an unexpected hydrolysis reaction of the amido niobium compound 2. Alternatively, monoguanidinato complexes [Nb(NMe2)2{N(2,6-(i)Pr2C6H3)}{(N(i)Pr)2C(NHR)}] (R = (i)Pr, 4, (n)Bu, 5) can be obtained by protonolysis of 1 with N,N',N''-alkylguanidines [(NH(i)Pr)2C(NR)] (R = (i)Pr, (n)Bu). Compound also reacts with either tert-butylisocyanide or 2,6-xylylisocyanide to give, by a migratory insertion reaction, the corresponding iminocarbamoyl compounds [Nb(NMe2)2{(NMe2)C=NR}{N(2,6-(i)Pr2C6H3)}] (R = (t)Bu, 6, Xy, 7). Addition of the neutral alkylguanidines to complex 6 results in a facile C-N bond cleavage at room temperature in a process directed by the formation of the stable chelate complex 4 or 5. Complex reacts with heterocumulenic CS2 to produce new imido dithiocarbamato complexes [Nb(NMe2){S2C(NMe2)}2{N(2,6-(i)Pr2C6H3)}] (8) and [Nb{S2C(NMe2)}3{N(2,6-(i)Pr2C6H3)}] (9). These complexes do not react with alkylguanines, although new mixed guanidinato dithiocarbamato complexes [Nb(NMe2){S2C(NMe2)}{(N(i)Pr)2C(NHiPr)}{N(2,6-(i)Pr2C6H3)}] (10) and [Nb{(S2C(NMe2)}2{(N(i)Pr)2C(NH(i)Pr)}{N(2,6-(i)Pr2C6H3)}] (11) can be obtained by reaction of complex 4 with one or two equivalents of CS2, respectively. All of the complexes were characterized spectroscopically and the dynamic behaviour of some of them was studied by variable-temperature NMR. The molecular structures of 2a, 3, 6 and 10 were also established by X-ray diffraction studies.

  2. Complex aberrations in lymphocytes exposed to mixed beams of (241)Am alpha particles and X-rays.

    PubMed

    Staaf, Elina; Deperas-Kaminska, Marta; Brehwens, Karl; Haghdoost, Siamak; Czub, Joanna; Wojcik, Andrzej

    2013-08-30

    Modern radiotherapy treatment modalities are associated with undesired out-of-field exposure to complex mixed beams of high and low energy transfer (LET) radiation that can give rise to secondary cancers. The biological effectiveness of mixed beams is not known. The aim of the investigation was the analysis of chromosomal damage in human peripheral blood lymphocytes (PBL) exposed to a mixed beam of X-rays and alpha particles. Using a dedicated exposure facility PBL were exposed to increasing doses of alpha particles (from (241)Am), X-rays and a mixture of both. Chromosomal aberrations were analysed in chromosomes 2, 8 and 14 using fluorescence in situ hybridisation. The found and expected frequencies of simple and complex aberrations were compared. Simple aberrations showed linear dose-response relationships with doses. A higher than expected frequency of simple aberrations was only observed after the highest mixed beam dose. A linear-quadratic dose response curve for complex aberrations was observed after mixed-beam exposure. Higher than expected frequencies of complex aberrations were observed for the two highest doses. Both the linear-quadratic dose-response relationship and the calculation of expected frequencies show that exposure of PBL to mixed beams of high and low LET radiation leads to a higher than expected frequency of complex-type aberrations. Because chromosomal changes are associated with cancer induction this result may imply that the cancer risk of exposure to mixed beams in radiation oncology may be higher than expected based on the additive action of the individual dose components.

  3. Synthesis and spectral characterization of trinuclear, oxo-centered, carboxylate-bridged, mixed-valence iron complexes with Schiff bases.

    PubMed

    Singh, Atresh Kumar; Singh, Alok Kumar

    2012-10-01

    Some novel trinuclear, oxo-centered, carboxylate-bridged, mixed-valence iron complexes of the general formula [Fe(3)O(OOCR)(3)(SB)(3)L(3)] (where R=C(13)H(27), C(15)H(31) or C(17)H(35,) HSB=Schiff bases and L=Ethanol) have been synthesized by the stepwise substitutions of acetate ions from μ(3)-oxo-hexa(acetato)tri(aqua)iron(II)diiron(III), first with straight chain carboxylic acids and then with Schiff bases. The complexes were characterized by elemental analyses, molecular weight determinations and spectral (electronic, infrared, FAB mass, Mössbauer and powder XRD) studies. Molar conductance measurements indicated the complexes to be non-electrolytes in nitrobenzene. Bridging nature of carboxylate and Schiff base anions in the complexes was established by their infrared spectra. Mössbauer spectroscopic studies indicated two quadrupole-split doublets due to Fe(II) and Fe(III) ions at 80, 200 and 295K, confirming the complexes are mixed-valence species. This was also supported by the observed electronic spectra of the complexes. Magnetic susceptibility measurements displayed octahedral geometry around iron in mixed-valence state and a net antiferromagnetic exchange coupling via μ-oxo atom. Trinuclear nature of the complexes was confirmed by their molecular weight determination and FAB mass spectra. A plausible structure for these complexes has been established on the basis of spectral and magnetic moment data. Copyright © 2012 Elsevier B.V. All rights reserved.

  4. Synthesis and spectral characterization of trinuclear, oxo-centered, carboxylate-bridged, mixed-valence iron complexes with Schiff bases

    NASA Astrophysics Data System (ADS)

    Singh, Atresh Kumar; Singh, Alok Kumar

    2012-10-01

    Some novel trinuclear, oxo-centered, carboxylate-bridged, mixed-valence iron complexes of the general formula [Fe3O(OOCR)3(SB)3L3] (where R = C13H27, C15H31 or C17H35, HSB = Schiff bases and L = Ethanol) have been synthesized by the stepwise substitutions of acetate ions from μ3-oxo-hexa(acetato)tri(aqua)iron(II)diiron(III), first with straight chain carboxylic acids and then with Schiff bases. The complexes were characterized by elemental analyses, molecular weight determinations and spectral (electronic, infrared, FAB mass, Mössbauer and powder XRD) studies. Molar conductance measurements indicated the complexes to be non-electrolytes in nitrobenzene. Bridging nature of carboxylate and Schiff base anions in the complexes was established by their infrared spectra. Mössbauer spectroscopic studies indicated two quadrupole-split doublets due to Fe(II) and Fe(III) ions at 80, 200 and 295 K, confirming the complexes are mixed-valence species. This was also supported by the observed electronic spectra of the complexes. Magnetic susceptibility measurements displayed octahedral geometry around iron in mixed-valence state and a net antiferromagnetic exchange coupling via μ-oxo atom. Trinuclear nature of the complexes was confirmed by their molecular weight determination and FAB mass spectra. A plausible structure for these complexes has been established on the basis of spectral and magnetic moment data.

  5. Mixed-spin [2 × 2] Fe4 grid complex optimized for quantum cellular automata.

    PubMed

    Schneider, Benjamin; Demeshko, Serhiy; Neudeck, Sven; Dechert, Sebastian; Meyer, Franc

    2013-11-18

    The new pyrazolate-bridged proligand 4-methyl-3,5-bis{6-(2,2'-bipyridyl)}pyrazole ((Me)LH) has been synthesized. Similar to its congener that lacks the backbone methyl substituent ((H)LH) it forms a robust Fe(II)4 grid complex, [(Me)L4Fe(II)4](BF4)4. The molecular structure of [(Me)L4Fe(II)4](BF4)4·2MeCN has been elucidated by X-ray diffraction, revealing two high-spin (HS) and two low-spin (LS) ferrous ions at opposite corners of the rhombic metal ion arrangement. SQUID and (57)Fe Mössbauer data for solid material showed that this [HS-LS-HS-LS] configuration persists over a wide temperature range, between 7 and 250 K, while spin-crossover sets in only above 250 K. According to Mössbauer spectroscopy a [1HS-3LS] configuration is present in solution at 80 K. Thus, the methyl substituent in [(Me)L](-) leads to a stronger ligand field compared to parent [(H)L](-) and hence to a higher LS fraction both in the solid state and in solution. Cyclic voltammetry of [(Me)L4Fe(II)4](BF4)4 reveals four sequential oxidations coming in two pairs with pronounced stability of the di-mixed-valence species [(Me)L4Fe(II)2Fe(III)2](6+) (K(C) = 3.35 × 10(8)). The particular [HS-LS-HS-LS] configuration as well as the di-mixed-valence configuration, both with identical spin or redox states at diagonally opposed vertices of the grid, make this system attractive as a molecular component for quantum cellular automata.

  6. A novel iterative mixed model to remap three complex orthopedic traits in dogs

    PubMed Central

    Huang, Meng; Hayward, Jessica J.; Corey, Elizabeth; Garrison, Susan J.; Wagner, Gabriela R.; Krotscheck, Ursula; Hayashi, Kei; Schweitzer, Peter A.; Lust, George; Boyko, Adam R.; Todhunter, Rory J.

    2017-01-01

    Hip dysplasia (HD), elbow dysplasia (ED), and rupture of the cranial (anterior) cruciate ligament (RCCL) are the most common complex orthopedic traits of dogs and all result in debilitating osteoarthritis. We reanalyzed previously reported data: the Norberg angle (a quantitative measure of HD) in 921 dogs, ED in 113 cases and 633 controls, and RCCL in 271 cases and 399 controls and their genotypes at ~185,000 single nucleotide polymorphisms. A novel fixed and random model with a circulating probability unification (FarmCPU) function, with marker-based principal components and a kinship matrix to correct for population stratification, was used. A Bonferroni correction at p<0.01 resulted in a P< 6.96 ×10−8. Six loci were identified; three for HD and three for RCCL. An associated locus at CFA28:34,369,342 for HD was described previously in the same dogs using a conventional mixed model. No loci were identified for RCCL in the previous report but the two loci for ED in the previous report did not reach genome-wide significance using the FarmCPU model. These results were supported by simulation which demonstrated that the FarmCPU held no power advantage over the linear mixed model for the ED sample but provided additional power for the HD and RCCL samples. Candidate genes for HD and RCCL are discussed. When using FarmCPU software, we recommend a resampling test, that a positive control be used to determine the optimum pseudo quantitative trait nucleotide-based covariate structure of the model, and a negative control be used consisting of permutation testing and the identical resampling test as for the non-permuted phenotypes. PMID:28614352

  7. Lidar Descriptions of Mixing-Layer Thickness Characteristics in a Complex Terrain/Coastal Environment.

    NASA Astrophysics Data System (ADS)

    McElroy, James L.; Smith, Ted B.

    1991-05-01

    Airborne lidar and supplementary measurements made during a major study of air chemistry in southern California (SCCCAMP 1985) provided a rare opportunity to examine atmospheric boundary-layer structure in a coastal area with complex terrain. This structure results from a combination of daytime heating or convection in the boundary layer (CBL), the intrusion of a marine layer into the inland areas, the thermal internal boundary layer (TIBL) formed within the marine onshore flow, inland growth of the TIBL, interactions of the CBL and the TIBL, and airflow interactions with terrain features.Measurements showed offshore mixing-layer thicknesses during SCCCAMP to be quite uniform spatially and day to day at 100-200 m. Movement of this layer onshore occurred readily with terrain that sloped gradually upward (e.g., to 300 m MSL at 50 km inland), but was effectively blocked by a 400-500 m high coastal ridge. In the higher terrain beyond the coastal ridge, aerosol layers aloft were often created as a result of deep convection and of a combination of onshore flow and heated, upslope airflow activity. Such aerosol layers can extend far offshore when embedded in reverse circulations aloft.The forward boundary of the marine layer was quite sharp, resembling a miniature cold front. Within the marine layer the onshore flow initiates a TIBL at the coastline, which increases in depth with distance inland due to roughness and convective influences. A coherent marine layer with imbedded TIBL was maintained for inland distances of 20-50 km, depending on terrain. Intense heating occurred inland prior to the arrival and undercutting by the marine front. The resulting, effective mixing layer increased in thickness from a few hundred meters to nearly two kilometers in a very short distance.Comparisons of a representative, physically based TIBL and convective mixing-layer models with observed data indicate that they generally do a credible job of estimating the depth of the marine layer

  8. Complex resistivity spectra in relation to multiscale pore geometry in carbonates and mixed-siliciclastic rocks

    NASA Astrophysics Data System (ADS)

    Norbisrath, Jan Henrik

    Carbonate rocks are known to have complex and heterogeneous pore structures, which result from their biogenic origin and strong affinity for diagenetic processes that change their pore structure after burial. The combination of sheer endless variations of precursor biogenic material, depositional environments, and diagenetic effects results in rocks that are interesting to study but intricate to understand. Many schemes to categorize the diversity of carbonate rocks are in use today; most are based on the macropore structure and qualitative thin-section analysis. Many studies, however, acknowledge that micropores have a significant influence on the macroscopic petrophysical rock properties, which are essential to determine reservoir quality. Micropores are, by definition, smaller than the thickness of a thin-section (< 30 microm) and hence cannot be quantified with conventional methods. For their analysis, scanning electron microscopy (SEM) is the logical next step. The challenge is that mechanical polishing methods produce excessive surface roughness at micron scale; the resulting surfaces are not suited for quantification of micropores. Advances in broad-ion-beam (BIB) milling enable preparation of nanometer-precision 2D sections that are suited for quantitative analysis with the SEM. To accomplish the objective of accurate quantification of carbonate micropores, part one of this dissertation employs the BIB-SEM technique on a variety of carbonate rock samples and finds four major carbonate microporosity types: (1) small intercrystalline, (2) large inter-crystalline, (3) intercement, and (4) micromoldic. Each microporosity type shows a distinct capacity to conduct electrical charge, which largely controls the magnitude and range of cementation factors (m) in rocks with such microporosity type. The BIB-SEM method is also used on a dataset of mixed carbonate-siliciclastic (mudrock) samples with high kerogen and pyrite content. Results show that the nanopore

  9. CHARMM-GUI micelle builder for pure/mixed micelle and protein/micelle complex systems.

    PubMed

    Cheng, Xi; Jo, Sunhwan; Lee, Hui Sun; Klauda, Jeffery B; Im, Wonpil

    2013-08-26

    Micelle Builder in CHARMM-GUI, http://www.charmm-gui.org/input/micelle , is a web-based graphical user interface to build pure/mixed micelle and protein/micelle complex systems for molecular dynamics (MD) simulation. The robustness of Micelle Builder is tested by simulating four detergent-only homogeneous micelles of DHPC (dihexanoylphosphatidylcholine), DPC (dodecylphosphocholine), TPC (tetradecylphosphocholine), and SDS (sodium dodecyl sulfate) and comparing the calculated micelle properties with experiments and previous simulations. As a representative protein/micelle model, Pf1 coat protein is modeled and simulated in DHPC micelles with three different numbers of DHPC molecules. While the number of DHPC molecules in direct contact with Pf1 protein converges during the simulation, distinct behavior and geometry of micelles lead to different protein conformations in comparison to that in bilayers. It is our hope that CHARMM-GUI Micelle Builder can be used for simulation studies of various protein/micelle systems to better understand the protein structure and dynamics in micelles as well as distribution of detergents and their dynamics around proteins.

  10. Site-selective XANES and EXAFS. A demonstration with manganese mixtures and mixed-valence complexes

    SciTech Connect

    Grush, M.M.; Christou, G.; Hamaelaeinen, K.; Cramer, S.P. |

    1995-05-31

    This paper presents the first demonstration that chemical shifts in X-ray fluorescence energies can be used to obtain site-selective X-ray absorption spectra. X-ray absorption spectroscopy (XAS) has become a powerful tool for probing both geometric and electronic structure. Here site-selective XANES and EXAFS using high-resolution fluorescence detection are demonstrated for a physical mixture of MnF{sub 2} and BaMn{sub 8}O{sub 16}{center_dot}2H{sub 2}O and for a Mn{sup II}Mn{sup III}{sub 2} mixed-valence complex, Mn{sub 3}O(O{sub 2}CPh){sub 6}(py){sub 2}(H{sub 2}O). There are many cases where fluorescence lines change with chemical environment; hence this method of site-selective XAS should have broad applicability. The main obstacle at the moment is signal-to-noise, but with new high-brightness synchrotron radiation sources and a larger collection solid angle, site-selective XAS using high-resolution fluorescence detection should become a more common and valuable technique. 24 refs., 2 figs.

  11. Study on spin configuration in photoresponsive iron mixed-valence complexes by Mössbauer spectroscopy

    NASA Astrophysics Data System (ADS)

    Okazawa, A.; Yoshida, J.; Kida, N.; Kashima, I.; Murata, W.; Enomoto, M.; Kojima, N.

    2014-04-01

    We have investigated magnetic properties in a series of photoresponsive dithiooxalato (dto)-bridged iron mixed-valence complexes, (SP-R)[FeIIFeIII(dto)3] (SP-R = R-substituted pyridospiropyran cation; R = Me, Et, and Pr; abbreviated as 1 Me, 1 Et, and 1 Pr, respectively). As for our previous reports, 1 Me and 1 Et show two-step succeeding ferromagnetic transitions at T C = 25 & 8 K and 22 & 5 K, respectively. However, 1 Et has no hysteresis in the magnetic susceptibility, while 1 Me undergoes the charge transfer phase transition with thermal hysteresis around 75 K. To elucidate the two-step transitions of them, we measured 57Fe Mössbauer spectra of 1 Et. The spectra of FeII ( S = 2) and FeIII ( S = 1/2) in the HTP were observed in the magnetically ordered state as well as the paramagnetic state, and revealed that only HTP exists in a temperature range up to 5 K. The result is consistent with that of 1 Pr, where one ferromagnetic phase transition occurs at T C = 10 K. 57Fe Mössbauer spectroscopy is useful to clarify the origin of the succeeding magnetic transition for these systems.

  12. Synthesizing evidence on complex interventions: how meta-analytical, qualitative, and mixed-method approaches can contribute.

    PubMed

    Petticrew, Mark; Rehfuess, Eva; Noyes, Jane; Higgins, Julian P T; Mayhew, Alain; Pantoja, Tomas; Shemilt, Ian; Sowden, Amanda

    2013-11-01

    Although there is increasing interest in the evaluation of complex interventions, there is little guidance on how evidence from complex interventions may be reviewed and synthesized, and the relevance of the plethora of evidence synthesis methods to complexity is unclear. This article aims to explore how different meta-analytical approaches can be used to examine aspects of complexity; describe the contribution of various narrative, tabular, and graphical approaches to synthesis; and give an overview of the potential choice of selected qualitative and mixed-method evidence synthesis approaches. The methodological discussions presented here build on a 2-day workshop held in Montebello, Canada, in January 2012, involving methodological experts from the Campbell and Cochrane Collaborations and from other international review centers (Anderson L, Petticrew M, Chandler J, et al. systematic reviews of complex interventions. In press). These systematic review methodologists discussed the broad range of existing methods and considered the relevance of these methods to reviews of complex interventions. The evidence from primary studies of complex interventions may be qualitative or quantitative. There is a wide range of methodological options for reviewing and presenting this evidence. Specific contributions of statistical approaches include the use of meta-analysis, meta-regression, and Bayesian methods, whereas narrative summary approaches provide valuable precursors or alternatives to these. Qualitative and mixed-method approaches include thematic synthesis, framework synthesis, and realist synthesis. A suitable combination of these approaches allows synthesis of evidence for understanding complex interventions. Reviewers need to consider which aspects of complex interventions should be a focus of their review and what types of quantitative and/or qualitative studies they will be including, and this will inform their choice of review methods. These may range from

  13. Complex regional pain syndrome (reflex sympathetic dystrophy) in a patient with essential mixed cryoglobulinemia and chronic hepatitis C.

    PubMed

    Bant, Ankur; Hurowitz, Bertram; Hassan, Nadeem; Du, Van Thiel; Nadir, Abdul

    2007-02-01

    Essential mixed cryoglobulinemia (EMC) is a common extra-hepatic manifestation of hepatitis C virus (HCV). Complex Regional Pain Syndrome type I (CRPS) or Reflex sympathetic dystrophy (RSD) has never been reported in association with HCV. This is the first case report of RSD in a patient with HCV related cirrhosis and EMC.

  14. Mixed metal hydroxycarboxylic acid complexes. Spectrophotometric study of complexes of U(VI) with In(III), Cu(II), Zn(II) and Cd(II)

    SciTech Connect

    Manzurola, E.; Apelblat, A.; Markovits, G.; Levy, O. )

    1988-01-01

    The formation of mixed metal complexes between uranium (VI), as the central metal ion, and aluminum (III), indium (III), copper (II), zinc (II) and cadmium (II), as the additional metal ions, with a hydroxycarboxylic acid chosen between citric, tartaric or malic, has been studied using spectrophotometric methods. The effect of pH has been examined, and the results show that at pH = 4 stable complexes are formed for most of the systems. At this pH the method of mole ratio and Job's method of continuous variations, were employed to determine the stoichiometry of the mixed metal complexes. Al(III), In(III) and Cu(II) showed a high tendency to form mixed metal complexes with U(VI), while the formation of complexes is uncertain for Cd(II) and Zn(II). The ratio of the ligand to the total metal ion has been found to be 2:1 and metal:metal ratios of 1:1 and 1:2 have been observed.

  15. Uncertainty estimation in sediment fingerprinting un-mixing models: impact of source characterisation and complexity

    NASA Astrophysics Data System (ADS)

    Sherriff, Sophie; Rowan, John; Franks, Stewart; Walden, John; Melland, Alice; Jordan, Phil; Fenton, Owen; hUallacháin, Daire Ó.

    2014-05-01

    Sediment fingerprinting techniques are being applied more frequently to inform soil and water management issues. Identification of sediment source areas and assessment of their relative contributions are essential in targeting cost-effective mitigation strategies. Sediment fingerprinting utilises natural sediment properties (e.g. chemical, magnetic, radiometric) to trace the contributions from different source areas by 'unmixing' a catchment outlet sample back to its constituent sources. Early qualitative approaches have been superseded by quantitative methodologies using multiple (composite) tracers coupled with linear programming. Despite the inclusion of fingerprinting results in environmental management strategies, techniques are subject to potentially significant uncertainties. Intra-source heterogeneity, although widely recognised as a source of uncertainty, is difficult to address, particularly in large study catchments, or where source collection is restricted. Inadequate characterisation may result in the translation of significant uncertainties to a group fingerprint and onward to contribution estimates. Franks and Rowan (2000) developed an uncertainty inclusive un-mixing model (FR2000+) based on Bayesian Monte-Carlo methods. Source area contributions are reported with confidence intervals which incorporate sampling and un-mixing uncertainties. Consequently the impact of uncertainty on the reliability of predictions can be considered. The aim of this study is to determine the impact of source area sampling resolution and spatial complexity on source area contribution estimates and their relative uncertainty envelope. High resolution source area sampling was conducted in a 10 km2 intensive grassland catchment in Co. Wexford, Ireland, according to potential field and non-field sources. Seven potential source areas were sampled; channel banks (n=55), road verges (n=44), topsoils (n=35), subsoils (n=32), tracks (n=6), drains (n=2) and eroding ditches (n=5

  16. Inpatient Complexity in Radiology-a Practical Application of the Case Mix Index Metric.

    PubMed

    Mabotuwana, Thusitha; Hall, Christopher S; Flacke, Sebastian; Thomas, Shiby; Wald, Christoph

    2017-01-12

    With ongoing healthcare payment reforms in the USA, radiology is moving from its current state of a revenue generating department to a new reality of a cost-center. Under bundled payment methods, radiology does not get reimbursed for each and every inpatient procedure, but rather, the hospital gets reimbursed for the entire hospital stay under an applicable diagnosis-related group code. The hospital case mix index (CMI) metric, as defined by the Centers for Medicare and Medicaid Services, has a significant impact on how much hospitals get reimbursed for an inpatient stay. Oftentimes, patients with the highest disease acuity are treated in tertiary care radiology departments. Therefore, the average hospital CMI based on the entire inpatient population may not be adequate to determine department-level resource utilization, such as the number of technologists and nurses, as case length and staffing intensity gets quite high for sicker patients. In this study, we determine CMI for the overall radiology department in a tertiary care setting based on inpatients undergoing radiology procedures. Between April and September 2015, CMI for radiology was 1.93. With an average of 2.81, interventional neuroradiology had the highest CMI out of the ten radiology sections. CMI was consistently higher across seven of the radiology sections than the average hospital CMI of 1.81. Our results suggest that inpatients undergoing radiology procedures were on average more complex in this hospital setting during the time period considered. This finding is relevant for accurate calculation of labor analytics and other predictive resource utilization tools.

  17. Ru, Os, Rh mixed-metal complexes are a potential novel class of oxygen independent photosensitizers for photodynamic therapy (PDT)

    NASA Astrophysics Data System (ADS)

    Storrie, Brian; Holder, Alvin; Brewer, Karen J.

    2006-02-01

    Mixed-metal supramolecular complexes coupling Ru and Os light absorber units to a central, reactive Rh site have been designed of the type [{(bpy)2M(dpp)}2RhCl2]5+. These complexes possess intense metal-to-ligand charge transfer transitions when excited at 500-700 nm making them good light absorbers. The presence of the Rh site introduces low lying metal-to-metal charge transfer states that are capable of visible light induced photocleavage of DNA via an oxygen independent pathway.1 We report here a study of the photodynamic action of supramolecular mixed-metal complexes showing that these systems inhibit cell replication after exposure to light while displaying no impact on cell replication in the dark. This photodynamic action has been studied using cultured Vero cells with a pre-incubation with the complexes, rinsing to remove complex from the media, followed by photo-activation and cell growth assay. The photodynamic action of this new series of complexes can be tuned as a function of components of the supramolecular assembly and complexes capable of coupling to targeting proteins and fluorescent reporter groups have been synthesized.

  18. A mixed quantum-classical description of excitation energy transfer in supramolecular complexes: Förster theory and beyond.

    PubMed

    Megow, Jörg; Röder, Beate; Kulesza, Alexander; Bonačić-Koutecký, Vlasta; May, Volkhard

    2011-02-25

    Electronic excitation energy transfer (EET) is described theoretically for the chromophore complex P(4) formed by a butanediamine dendrimer to which four pheophorbide-a molecules are covalently linked. To achieve a description with atomic resolution, and to account for the effect of an ethanol solvent, a mixed quantum-classical methodology is utilized. Room-temperature molecular dynamics simulations are used to describe the nuclear dynamics, and EET is accounted for in utilizing a mixed quantum-classical formulation of the transition rates. Therefore, the full quantum expression of the EET rates is given and the change to a mixed quantum-classical version is briefly explained. The description results in the calculation of transition rates which coincide rather satisfactory with available experimental data on P(4). It is also shown that different assumptions of classical Förster theory are not valid for P(4). The temporal behavior of EET deduced from the rate equations is confronted with that following from the solution of the time-dependent Schrödinger equation entering the mixed quantum-classical description of EET. From this we can conclude that EET in flexible chromophore complexes such as P(4) can be rather satisfactory estimated by single transition rates. A correct description, however, is only achievable by using a sufficiently large set of rates that correspond to the various possible equilibrium configurations of the complex.

  19. The impact of mixed solvents on the complexation thermodynamics of Eu(III) by simple carboxylate and amino carboxylate ligands

    DOE PAGES

    Felmy, Heather M.; Bennett, Kevin T.; Clark, Sue B.

    2017-05-12

    To gain insight on the role of mixed solvents on the thermodynamic driving forces for the complexation between trivalent f-elements and organic ligands, solution phase thermodynamic parameters were determined for Eu(III) complexation with 2-hydroxyisobutyric acid (HIBA) and 2-aminoisobutyric acid (AIBA) in mixed methanol (MeOH)-water and N,N-dimethylformamide (DMF)-water solvents. Included in this study were the determination of mixed solvent autoprotolysis constants (pKα) as well as the thermodynamic formation constants: log β, ΔG, ΔH, and ΔS, for ligand protonation and Eu(III)-ligand complexation utilizing potentiometry and calorimetry techniques. The results presented are conditional thermodynamic values determined at an ionic strength of 1.0 Mmore » NaClO4 and a temperature of 298 K. It was found that moving from an aqueous solution to a binary aqueous-organic solvent affected all solution equilibria to some degree and that the extent of change depended on both the type of mixed solvent and the ligand in each study. Here, the ability to understand and predict these changes in thermodynamic values as a function of solvent composition provides important information about the chemistry of the trivalent f-elements.« less

  20. Synthesis, spectral and thermal studies of some transition metal mixed ligand complexes: Modeling of equilibrium composition and biological activity

    NASA Astrophysics Data System (ADS)

    Neelakantan, M. A.; Sundaram, M.; Nair, M. Sivasankaran

    2011-09-01

    Several mixed ligand Ni(II), Cu(II) and Zn(II) complexes of 2-amino-3-hydroxypyridine (AHP) and imidazoles viz., imidazole (him), benzimidazole (bim), histamine (hist) and L-histidine (his) have been synthesized and characterized by elemental and spectral (vibrational, electronic, 1H NMR and EPR) data as well as by magnetic moment values. On the basis of elemental analysis and molar conductance values, all the complexes can be formulated as [MAB]Cl except histidine complexes as MAB. Thermogravimetric studies reveal the presence of coordinated water molecules in most of the complexes. From the magnetic measurements and electronic spectral data, octahedral structure was proposed for Ni(II) and Cu(II)-AHP-his, tetrahedral for Cu(II)-AHP-him/bim/hist, but square planar for the Cu(II)-AHP complex. The g∥/ A∥ calculated supports tetrahedral environment around the Cu(II) in Cu(II)-AHP-him/bim/hist and distorted octahedral for Cu(II)-AHP-his complexes. The morphology of the reported metal complexes was investigated by scanning electron micrographs (SEM). The potentiometric study has been performed in aqueous solution at 37 °C and I = 0.15 mol dm -3 NaClO 4. MABH, MAB and MAB 2 species has been identified in the present systems. Proton dissociation constants of AHP and stability constants of metal complexes were determined using MINIQUAD-75. The most probable structure of the mixed ligand species is discussed based upon their stability constants. The in vitro biological activity of the complexes was tested against the Gram positive and Gram negative bacteria, fungus and yeast. The oxidative DNA cleavage studies of the complexes were performed using gel electrophoresis method. Cu(II) complexes have been found to promote DNA cleavage in presence of biological reductant such as ascorbate and oxidant like hydrogen peroxide.

  1. Mixed Heritage Said to Present Complex Issues: Multiracial Children Attracting Interest as Visibility Increases

    ERIC Educational Resources Information Center

    Viadero, Debra

    2009-01-01

    With Barack Obama making history by becoming the United States' first mixed-race president, his inauguration is calling attention to the nation's growing multiracial population, whose youngest members are showing up with increasing frequency at schoolhouse doors. Yet while the growth of the U.S. population of children with mixed-race backgrounds…

  2. Mixed-valence state of a pyrazine-bridged dimer of oxocarboxylatotriruthenium complexes with a nitrosyl ligand.

    PubMed

    Ohtsu, Hiroyoshi; Fujiwara, Naoya; Yamaguchi, Tadashi

    2011-08-15

    Three new pyrazine-bridged dimers of oxoacetatotriruthenium with an NO ligand are synthesized. These complexes show two types of stable mixed-valence states. The ν(NO) stretches for five oxidation states were obtained, and the intramolecular electron-transfer rate within the mixed-valence state is evaluated from the IR spectral line-shape simulation based on Bloch-type analysis, which is the first application of this method to a spectator ligand of NO. © 2011 American Chemical Society

  3. THz generation by two-color femtosecond filaments with complex polarization states: four-wave mixing versus photocurrent contributions

    NASA Astrophysics Data System (ADS)

    Fedorov, V. Yu; Koulouklidis, A. D.; Tzortzakis, S.

    2017-01-01

    Two-color filamenation in gases is known to produce intense and broadband THz radiation. There are two physical mechanisms responsible for the THz generation in this scheme: four-wave mixing and emission from the induced plasma currents. The case when the main and second harmonic are linearly polarized is well studied including the impact from each of the above mechanisms. However, for the cases when the two-color fields have complex polarization states the role of the four-wave mixing and plasma mechanisms in the formation of the THz polarization is still under-explored. Here we use both the four-wave mixing and photocurrent models in order to consider the THz generation by two-color fields with arbitrary polarizations. We show that under specific polarizations of the two-color field components it is possible to determine which of the mechanisms is responsible for the THz polarization formation.

  4. Recent advances in phenoxyl radical complexes of salen-type ligands as mixed-valent galactose oxidase models

    PubMed Central

    Lyons, Christopher T.; Stack, T. Daniel P.

    2012-01-01

    The interplay between redox-active transition metal ions and redox-active ligands in metalloenzyme sites is an area of considerable research interest. Galactose oxidase (GO) is the archetypical example, catalyzing the aerobic oxidation of primary alcohols to aldehydes via two one-electron cofactors: a copper atom and a cysteine-modified tyrosine residue. The electronic structure of the oxidized form of the enzyme (GOox) has been investigated extensively through small molecule analogues including metal-salen phenoxyl radical complexes. Similar to GOox, one-electron oxidized metal-salen complexes are mixed-valent species, in which molecular orbitals (MOs) with predominantly phenolate and phenoxyl π-character act as redox-active centers bridged by mixing with metal d-orbitals. A detailed evaluation of the electronic distribution in these odd electron species using a variety of spectroscopic, electrochemical, and theoretical techniques has led to keen insights into the electronic structure of GOox. PMID:23264696

  5. Synthesis, structure characterization and biological activity of selected metal complexes of sulfonamide Schiff base as a primary ligand and some mixed ligand complexes with glycine as a secondary ligand

    NASA Astrophysics Data System (ADS)

    Sharaby, Carmen M.; Amine, Mona F.; Hamed, Asmaa A.

    2017-04-01

    The current work reports synthesis of metal complexes and mixed ligand complexes of a novel sulfonamide Schiff base ligand (HL) resulted from the condensation of sulfametrole [N‧-(4-methoxy-1,2,5-thiadiazol-3-yl]sulfanilamide and acetyl-acetone as a primary ligand and glycine as a secondary ligand. The metal complexes and mixed ligand complexes of HL Schiff base ligand were synthesized and characterized using different physicochemical studies as elemental analyses, mass spectra, conductivity measurement, IR spectra, 1H NMR spectra, UV-vis Spectra, solid reflectance, magnetic susceptibility, thermal analyses (TGA and DTA) and their microbial and anticancer activities. The spectroscopic data of the complexes suggest their 1:2(L1:M) complex structures and 1:2:2(L1:L2:M) mixed ligand complex structures, where L1 = HL and L2 = glycine. Also, the spectroscopic studies suggested the octahedral structure for all complexes. The synthesized Schiff base, its metal and mixed ligand complexes were screened for their bacterial, antifungal and anticancer activity. The activity data show that the metal complexes and mixed ligand complexes exhibited promising microbial and anticancer activities than their parent HL Schiff base ligand, also the data show that the mixed ligand complexes more effective than the metal complexes.

  6. A Comparison Study of Fixed and Mixed Effect Models for Gene Level Association Studies of Complex Traits.

    PubMed

    Fan, Ruzong; Chiu, Chi-Yang; Jung, Jeesun; Weeks, Daniel E; Wilson, Alexander F; Bailey-Wilson, Joan E; Amos, Christopher I; Chen, Zhen; Mills, James L; Xiong, Momiao

    2016-12-01

    In association studies of complex traits, fixed-effect regression models are usually used to test for association between traits and major gene loci. In recent years, variance-component tests based on mixed models were developed for region-based genetic variant association tests. In the mixed models, the association is tested by a null hypothesis of zero variance via a sequence kernel association test (SKAT), its optimal unified test (SKAT-O), and a combined sum test of rare and common variant effect (SKAT-C). Although there are some comparison studies to evaluate the performance of mixed and fixed models, there is no systematic analysis to determine when the mixed models perform better and when the fixed models perform better. Here we evaluated, based on extensive simulations, the performance of the fixed and mixed model statistics, using genetic variants located in 3, 6, 9, 12, and 15 kb simulated regions. We compared the performance of three models: (i) mixed models that lead to SKAT, SKAT-O, and SKAT-C, (ii) traditional fixed-effect additive models, and (iii) fixed-effect functional regression models. To evaluate the type I error rates of the tests of fixed models, we generated genotype data by two methods: (i) using all variants, (ii) using only rare variants. We found that the fixed-effect tests accurately control or have low false positive rates. We performed simulation analyses to compare power for two scenarios: (i) all causal variants are rare, (ii) some causal variants are rare and some are common. Either one or both of the fixed-effect models performed better than or similar to the mixed models except when (1) the region sizes are 12 and 15 kb and (2) effect sizes are small. Therefore, the assumption of mixed models could be satisfied and SKAT/SKAT-O/SKAT-C could perform better if the number of causal variants is large and each causal variant contributes a small amount to the traits (i.e., polygenes). In major gene association studies, we argue that the

  7. Synthesis of mixed Cp/Tp(Me2) lanthanide complexes from lanthanocene precursors and their structures and reactivities.

    PubMed

    Han, Fuyan; Zhang, Jie; Han, Yanan; Zhang, Zhengxing; Chen, Zhenxia; Weng, Linhong; Zhou, Xigeng

    2009-02-16

    Reaction of Cp(2)LnCl with 1 equiv of KTp(Me2) in toluene gives the mixed Tp(Me2)/Cp lanthanide complexes Cp(2)Ln(Tp(Me2)) (Ln = Yb (1a), Er (1b), Dy (1c)), while unexpected complexes CpLn(Tp(Me2))Cl(THF) (Ln = Yb (2a), Er (2b.THF), Dy (2c), Y (2d)) are obtained when the reactions are carried out in THF. Complex 2b can also be formed by the reaction of CpErCl(2)(THF)(3) with 1 equiv of KTp(Me2) in THF. Moreover, complex 1a can also be obtained from the reaction of Cp(3)Yb and KTp(Me2). The results not only represent an efficient and versatile method for the synthesis of mixed Cp/Tp(Me2) lanthanide complexes but also provide new insight into the reactivity of Cp(2)LnCl. Furthermore, the reactivities of complexes 1a-c toward proton-donating reagents are examined. It has been found that 1b reacts with benzotriazole (C(6)H(4)NHN(2)) in THF to yield a lanthanide metallomacrocyclic complex [(Tp(Me2))CpEr(mu-N(3)C(6)H(4))](3) (3), while the reaction of 1a with 1 equiv of 2-aminopyridine in THF gives an unexpected oxide complex [(Tp(Me2))Yb(2-HNC(5)H(4)N)](2)(mu-O) (4). Presumably, the oxide ligand of compound 4 results from adventitious water. In addition, treatment of 1c with 2 equiv of 3,5-dimethylpyrazole yields a completely Cp-abstracted product (Tp(Me2))Dy(Pz(Me2))(2)(THF) (5), which can also be directly obtained from a three-component reaction of Cp(2)DyCl, KTp(Me2), and 3,5-dimethylpyrazole in THF. These results further indicate that the new mixed Tp(Me2)/Cp lanthanide complexes are practical and versatile precursors for the synthesis of poly(pyrazolyl)borate lanthanide derivatives. All new compounds have been characterized by elemental analysis and spectroscopic methods. The structures of complexes 1a,b and 2-5 have also been determined through single-crystal X-ray diffraction analysis.

  8. Mixed-method research protocol: defining and operationalizing patient-related complexity of nursing care in acute care hospitals.

    PubMed

    Huber, Evelyn; Kleinknecht-Dolf, Michael; Müller, Marianne; Kugler, Christiane; Spirig, Rebecca

    2017-06-01

    To define the concept of patient-related complexity of nursing care in acute care hospitals and to operationalize it in a questionnaire. The concept of patient-related complexity of nursing care in acute care hospitals has not been conclusively defined in the literature. The operationalization in a corresponding questionnaire is necessary, given the increased significance of the topic, due to shortened lengths of stay and increased patient morbidity. Hybrid model of concept development and embedded mixed-methods design. The theoretical phase of the hybrid model involved a literature review and the development of a working definition. In the fieldwork phase of 2015 and 2016, an embedded mixed-methods design was applied with complexity assessments of all patients at five Swiss hospitals using our newly operationalized questionnaire 'Complexity of Nursing Care' over 1 month. These data will be analysed with structural equation modelling. Twelve qualitative case studies will be embedded. They will be analysed using a structured process of constructing case studies and content analysis. In the final analytic phase, the quantitative and qualitative data will be merged and added to the results of the theoretical phase for a common interpretation. Cantonal Ethics Committee Zurich judged the research programme as unproblematic in December 2014 and May 2015. Following the phases of the hybrid model and using an embedded mixed-methods design can reach an in-depth understanding of patient-related complexity of nursing care in acute care hospitals, a final version of the questionnaire and an acknowledged definition of the concept. © 2016 John Wiley & Sons Ltd.

  9. Molybdenum complexes supported by mixed NHC/phosphine ligands: activation of N2 and reaction with P(OMe)3 to the first meta-phosphite complex.

    PubMed

    Gradert, Christian; Stucke, Nadja; Krahmer, Jan; Näther, Christian; Tuczek, Felix

    2015-01-12

    Molybdenum(0) dinitrogen complexes, supported by the mixed NHC/phosphine pincer ligand PCP, exhibit an extreme activation of the N2 ligand due to a very π-electron-rich metal center. The low thermal stability of these compounds can be increased using phosphites instead of phosphines as coligands. Through an amalgam reduction of [MoCl3(PCP)] in the presence of trimethyl phosphite and N2 the highly activated and room-temperature stable dinitrogen complex [Mo(N2)(PCP)(P(OMe)3)2] is obtained. As a second product, the first transition metal complex containing the meta-phosphite ligand P(O)(OMe) originates from this reaction. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Influence of mixed-ligand complexes on retention and distribution of radioniobium in mice

    SciTech Connect

    Gachalyi, A.; Namenyi, J.; Szegedi, I.; Varga, L.P.

    1987-11-01

    The individual effects of desferrioxamine B (DFOA), Na3Ca diethylenetriaminepentaacetic acid (DTPA), Na-salicylate, DL-penicillamine, and 2-aminoethylisothiouronium bromide hydrobromide, as well as the effect of mixed-ligand treatment on the retention and elimination of /sup 95/Nb in mice have been examined. It was found that /sup 95/Nb could easily be mobilized by a single dose of DFOA, but the best result was obtained with the DFOA and DTPA combination. Mixed-ligand treatment did not change the deposition characteristics and translocation kinetics of /sup 95/Nb.

  11. Synthesis, Characterization, and Antibacterial Studies of Mixed Ligand Dioxouranium Complexes with 8-Hydroxyquinoline and Some Amino Acids

    PubMed Central

    Patil, Sunil S.; Thakur, Ganesh A.; Shaikh, Manzoor M.

    2011-01-01

    Mixed ligand complexes of dioxouranium (VI) of the type [UO2(Q)(L)·2H2O] have been synthesized using 8-hydroxyquinoline (HQ) as a primary ligand and amino acids (HL) such as L-threonine, L-tryptophan, and L-isoleucine as secondary ligands. The metal complexes have been characterized by elemental analysis, electrical conductance, magnetic susceptibility measurements, and spectral and thermal studies. The electrical conductance studies of the complexes indicate their nonelectrolytic nature. Magnetic susceptibility measurements revealed diamagnetic nature of the complexes. Electronic absorption spectra of the complexes show intraligand and charge transfer transitions, respectively. Bonding of the metal ion through N- and O-donor atoms of the ligands is revealed by IR studies, and the chemical environment of the protons is confirmed by NMR studies. The thermal analysis data of the complexes indicate the presence of coordinated water molecules. The agar cup and tube dilution methods have been used to study the antibacterial activity of the complexes against the pathogenic bacteria S. aureus, C. diphtheriae, S. typhi, and E. coli. PMID:22389843

  12. Synthesis, DNA/HSA Interaction Spectroscopic Studies and In Vitro Cytotoxicity of a New Mixed Ligand Cu(II) Complex.

    PubMed

    Gan, Qian; Fu, Xiabing; Chen, Weijiang; Xiong, Yahong; Fu, Yinlian; Chen, Shi; Le, Xueyi

    2016-05-01

    A new mixed ligand copper(II)-dipeptide complex with 2-(2'-pyridyl)benzothiazole (pbt), [Cu(Gly-L-leu)(pbt)(H2O)]·ClO4 (Gly-L-leu = Glycyl-L-leucine anion) was synthesized and characterized by various physico-chemical means. The DNA binding and cleavage properties of the complex investigated by viscosity, agarose gel electrophoresis and multi-spectroscopic techniques (UV, circular dichroism (CD) and fluorescence) showed that the complex was bound to CT-DNA through intercalation mode with moderate binding constant (K b = 3.132 × 10(4) M(-1)), and cleaved pBR322 DNA efficiently (~ 5 μM) in the presence of Vc, probably via an oxidative mechanism induced by •OH. Additionally, the interaction of the complex with human serum albumin (HSA) was explored by UV-visible, CD, fluorescence, synchronous fluorescence and 3D fluorescence spectroscopy. The complex exhibits desired affinity to HSA through hydrophobic interaction. Moreover, the cytotoxicity of the complex against three human carcinoma cell lines (HeLa, HepG2 and A549) was evaluated by MTT assay, which showed that the complex had effective cytotoxicity and higher inhibition toward A549 cell lines with IC50 of 38.0 ± 3.2 μM.

  13. Facile preparation of mono-, di- and mixed-carboxylato platinum(IV) complexes for versatile anticancer prodrug design.

    PubMed

    Zhang, Jenny Z; Bonnitcha, Paul; Wexselblatt, Ezequiel; Klein, Alice V; Najajreh, Yousef; Gibson, Dan; Hambley, Trevor W

    2013-01-28

    Facile strategies were developed for the versatile functionalization of platinum(IV) axial sites, allowing for easy accessibility to unsymmetric mono- and mixed-carboxylato, as well as symmetric di-substituted platinum(IV) complexes. The first method involves the direct oxidation and carboxylation of the platinum(II) center using an appropriate peroxide and the carboxylate of choice to firstly yield a monocarboxylato monohydroxido platinum(IV) complex. This platinum(IV) intermediate can undergo further carboxylation to give rise to a mixed-carboxylato platinum(IV) complex. The second method involves the activation of the carboxylate of choice by a common carbodiimide coupling reagent, and its reaction with a dihydroxido platinum(IV) precursor to give the monocarboxylato platinum(IV) complex. Uronium salts can be employed to promote efficient dicarboxylation of the dihydroxido platinum(IV) precursor. Lastly, an axial azide pendant group was demonstrated to be suitable for orthogonal "click" conjugation reactions. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Estimation of Complex Generalized Linear Mixed Models for Measurement and Growth

    ERIC Educational Resources Information Center

    Jeon, Minjeong

    2012-01-01

    Maximum likelihood (ML) estimation of generalized linear mixed models (GLMMs) is technically challenging because of the intractable likelihoods that involve high dimensional integrations over random effects. The problem is magnified when the random effects have a crossed design and thus the data cannot be reduced to small independent clusters. A…

  15. Estimation of Complex Generalized Linear Mixed Models for Measurement and Growth

    ERIC Educational Resources Information Center

    Jeon, Minjeong

    2012-01-01

    Maximum likelihood (ML) estimation of generalized linear mixed models (GLMMs) is technically challenging because of the intractable likelihoods that involve high dimensional integrations over random effects. The problem is magnified when the random effects have a crossed design and thus the data cannot be reduced to small independent clusters. A…

  16. Turbulent Fluxes and Pollutant Mixing during Wintertime Air Pollution Episodes in Complex Terrain.

    PubMed

    Holmes, Heather A; Sriramasamudram, Jai K; Pardyjak, Eric R; Whiteman, C David

    2015-11-17

    Cold air pools (CAPs) are stagnant stable air masses that form in valleys and basins in the winter. Low wintertime insolation limits convective mixing, such that pollutant concentrations can build up within the CAP when pollutant sources are present. In the western United States, wintertime CAPs often persist for days or weeks. Atmospheric models do not adequately capture the strength and evolution of CAPs. This is in part due to the limited availability of data quantifying the local turbulence during the formation, maintenance, and destruction of persistent CAPs. This paper presents observational data to quantify the turbulent mixing during two CAP episodes in Utah's Salt Lake Valley during February of 2004. Particulate matter (PM) concentration data and turbulence measurements for CAP and non-CAP time periods indicate that two distinct types of mixing scenarios occur depending on whether the CAP is dry or cloudy. Where cloudy, CAPs have enhanced vertical mixing due to top-down convection from the cloud layer. A comparison between the heat and momentum fluxes during 5 days of a dry CAP episode in February to those of an equivalent 5 day time period in March with no CAP indicates that the average turbulent kinetic energy during the CAP was suppressed by approximately 80%.

  17. Mixed-ligand copper(II) phenolate complexes: Synthesis, spectral characterization, phosphate-hydrolysis, antioxidant, DNA interaction and cytotoxic studies

    NASA Astrophysics Data System (ADS)

    Gurumoorthy, Perumal; Mahendiran, Dharmasivam; Prabhu, Durai; Arulvasu, Chinnasamy; Rahiman, Aziz Kalilur

    2015-01-01

    A series of phenol-based mixed-ligand copper(II) complexes of the type [CuL1-4(diimine)] (1-8), where L1-4 = N1,N2-bis(5-substituted-2-hydroxybenzylidene)-1,2-ethylene/phenylenediimine and diimine = 2,2‧-bipyridyl (bpy) or 1,10-phenanthroline (phen), have been isolated and fully characterized by analytical and spectral techniques. Electronic spectra of complexes suggest Cu(II) cation has a d9 electronic configuration, adopting distorted octahedral geometry with axial elongation, due to Jahn-Teller effect. Electrochemical studies of complexes evidenced one-electron irreversible reduction wave in the cathodic region. The observed rate constant (k) values for the hydrolysis of 4-nitrophenylphosphate (4-NPP) are in the range of 0.25-3.82 × 10-2 min-1. The obtained room temperature magnetic moment values (1.79-1.90 BM) lies within the range observed for octahedral copper(II) complexes. Antioxidant studies revealed that these complexes possess considerable radical scavenging potency against DPPH. The binding studies of complexes with calf thymus DNA (CT-DNA) revealed intercalation with minor-groove binding, and the complex 4 exhibits highest binding activity than the other complexes. The cleavage activity on supercoiled pBR322 DNA revealed the involvement of hydroxyl radical and singlet-oxygen as reactive oxygen species, and complexes encourage binding to minor-groove. Further, the cytotoxicity of complex 4 on human hepatocellular liver carcinoma HepG2 cell line implies the cell death through apoptosis.

  18. Stability Constants of Mixed Ligand Complexes of Nickel(II) with Adenine and Some Amino Acids

    PubMed Central

    Türkel, Naciye

    2015-01-01

    Nickel is one of the essential trace elements found in biological systems. It is mostly found in nickel-based enzymes as an essential cofactor. It forms coordination complexes with amino acids within enzymes. Nickel is also present in nucleic acids, though its function in DNA or RNA is still not clearly understood. In this study, complex formation tendencies of Ni(II) with adenine and certain L-amino acids such as aspartic acid, glutamic acid, asparagine, leucine, phenylalanine, and tryptophan were investigated in an aqueous medium. Potentiometric equilibrium measurements showed that both binary and ternary complexes of Ni(II) form with adenine and the above-mentioned L-amino acids. Ternary complexes of Ni(II)-adenine-L-amino acids are formed by stepwise mechanisms. Relative stabilities of the ternary complexes are compared with those of the corresponding binary complexes in terms of Δlog10⁡K, log10⁡X, and % RS values. It was shown that the most stable ternary complex is Ni(II):Ade:L-Asn while the weakest one is Ni(II):Ade:L-Phe in aqueous solution used in this research. In addition, results of this research clearly show that various binary and ternary type Ni(II) complexes are formed in different concentrations as a function of pH in aqueous solution. PMID:26843852

  19. A new generation of metal string complexes: structure, magnetism, spectroscopy, theoretical analysis, and single molecular conductance of an unusual mixed-valence linear [Ni5]8+ complex.

    PubMed

    Liu, Isiah Po-Chun; Bénard, Marc; Hasanov, Hasan; Chen, I-Wen Peter; Tseng, Wei-Hsiang; Fu, Ming-Dung; Rohmer, Marie-Madeleine; Chen, Chun-hsien; Lee, Gene-Hsiang; Peng, Shie-Ming

    2007-01-01

    Two new linear pentanickel complexes [Ni5(bna)4(Cl)2][PF6]2 (1) and [Ni5(bna)4(Cl)2][PF6]4 (2; bna=binaphthyridylamide), were synthesized and structurally characterized. A derivative of 1, [Ni5(bna)4(NCS)2][NCS]2 (3), was also isolated for the purpose of the conductance experiments carried out in comparison with [Ni5(tpda)4(NCS)2] (4; tpda=tripyridyldiamide). The metal framework of complex 2 is a standard [Ni5]10+ core, isoelectronic with that of [Ni5(tpda)4Cl2] (5). Also as in 5, complex 2 has an antiferromagnetic ground state (J=-15.86 cm(-1)) resulting from a coupling between the terminal nickel atoms, both in high-spin sate (S=1). Complex 1 displays the first characterized linear nickel framework in which the usual sequence of NiII atoms has been reduced by two electrons. Each dinickel unit attached to the naphthyridyl moieties is assumed to undergo a one-electron reduction, whereas the central nickel formally remains NiII. DFT calculations suggest that the metal framework of the mixed-valence complex 1 should be described as intermediate between a localized picture corresponding to NiII-NiI-NiII-NiI-NiII and a fully delocalized model represented as (Ni2)3+-NiII-(Ni2)3+. Assuming the latter model, the ground state of 1 results from an antiferromagnetic coupling (J=-34.03 cm(-1)) between the two (Ni2)3+ fragments, considered each as a single magnetic centre (S=3/2). An intervalence charge-transfer band is observed in the NIR spectrum of 1 at 1186 nm, suggesting, in accordance with DFT calculations, that 1 should be assigned to Robin-Day class II of mixed-valent complexes. Scanning tunnelling microscopy (STM) methodology was used to assess the conductance of single molecules of 3 and 4. Compound 3 was found approximately 40% more conductive than 4, a result that could be assigned to the electron mobility induced by mixed-valency in the naphthyridyl fragments.

  20. Mixing Bandt-Pompe and Lempel-Ziv approaches: another way to analyze the complexity of continuous-state sequences

    NASA Astrophysics Data System (ADS)

    Zozor, S.; Mateos, D.; Lamberti, P. W.

    2014-05-01

    In this paper, we propose to mix the approach underlying Bandt-Pompe permutation entropy with Lempel-Ziv complexity, to design what we call Lempel-Ziv permutation complexity. The principle consists of two steps: (i) transformation of a continuous-state series that is intrinsically multivariate or arises from embedding into a sequence of permutation vectors, where the components are the positions of the components of the initial vector when re-arranged; (ii) performing the Lempel-Ziv complexity for this series of `symbols', as part of a discrete finite-size alphabet. On the one hand, the permutation entropy of Bandt-Pompe aims at the study of the entropy of such a sequence; i.e., the entropy of patterns in a sequence (e.g., local increases or decreases). On the other hand, the Lempel-Ziv complexity of a discrete-state sequence aims at the study of the temporal organization of the symbols (i.e., the rate of compressibility of the sequence). Thus, the Lempel-Ziv permutation complexity aims to take advantage of both of these methods. The potential from such a combined approach - of a permutation procedure and a complexity analysis - is evaluated through the illustration of some simulated data and some real data. In both cases, we compare the individual approaches and the combined approach.

  1. Dinuclear Zn(II) and mixed Cu(II)-Zn(II) complexes of artificial patellamides as phosphatase models.

    PubMed

    Comba, Peter; Eisenschmidt, Annika; Gahan, Lawrence R; Hanson, Graeme R; Mehrkens, Nina; Westphal, Michael

    2016-12-21

    The patellamides (cyclic pseudo-octapeptides) are produced by Prochloron, a symbiont of the ascidians, marine invertebrate filter feeders. These pseudo-octapeptides are present in the cytoplasm and a possible natural function of putative metal complexes of these compounds is hydrolase activity, however the true biological role is still unknown. The dinuclear Cu(II) complexes of synthetic patellamide derivatives have been shown in in vitro experiments to be efficient hydrolase model catalysts. Many hydrolase enzymes, specifically phosphatases and carboanhydrases, are Zn(II)-based enzymes and therefore, we have studied the Zn(II) and mixed Zn(II)/Cu(II) solution chemistry of a series of synthetic patellamide derivatives, including solution structural and computational work, with the special focus on model phosphatase chemistry with bis-(2,4-dinitrophenyl)phosphate (BDNPP) as the substrate. The Zn(II) complexes of a series of ligands are shown to form complexes of similar structure and stability compared to the well-studied Cu(II) analogues and the phosphatase reactivities are also similar. Since the complex stabilities and phosphatase activities are generally a little lower compared to those of Cu(II) and since the concentration of Zn(II) in Prochloron cells is slightly smaller, we conclude that the Cu(II) complexes of the patellamides are more likely to be of biological importance.

  2. Synthesis and cytotoxicity of new platinum(IV) complexes of mixed carboxylates.

    PubMed

    Song, Rita; Park, Sun Young; Kim, Yeong Sang; Kim, Youngmee; Kim, Sung Jin; Ahn, Byung Tae; Sohn, Youn Soo

    2003-08-01

    In order to develop new antitumor platinum(IV) complexes with highly tuned lipophilicity, a series of (diamine)Pt(IV) complexes of the formula [Pt(IV)(dach)L(3)L'] or [Pt(IV)(dach)L(2)L"(2)] (dach=trans-(+/-)-1,2-diaminocyclohexane; L=acetato, propionato; L'=acetato, propionato, valerato or pivalato; L"=trifluoroacetato) have been synthesized by electrophilic substitution of the tris(carboxylato)hydroxoplatinum(IV) complexes, [Pt(IV)(dach)L(3)OH] (L=acetato, propionato), with various carboxylic anhydrides such as acetic, trifluoroacetic, pivalic and valeric anhydrides. The present platinum(IV) complexes were fully characterized by means of elemental analyses, 1H NMR, mass and IR spectroscopies. The complexes 8 and 10, satisfying the appropriate range of lipophilicity (logP=0.18-1.54), exhibited high activity (ED(50), 5.1 and 1.3 microM, respectively) compared with other complexes, which implies that the lipophilicity is an important factor for the antitumor activity of this series of complexes.

  3. Stoichiometry of the heparin-Cu2+-glycine mixed-ligand complex according to differential thermal analysis and IR spectroscopy data

    NASA Astrophysics Data System (ADS)

    Feofanova, M. A.; Frantseva, Yu. V.; Zhuravlev, E. V.; Baranova, N. V.; Ryasenskii, S. S.

    2015-02-01

    A method or the synthesis, isolation, and purification of a mixed-ligand complex of heparin with copper and glycine cations was suggested. The complex was studied by elemental, thermal, and spectral analyses. The elemental and crystalline hydrate compositions of the complex were determined and the molecular formula was suggested to be Na3CuHepGly · 2H2O.

  4. Capturing the multiscale dynamics of membrane protein complexes with all-atom, mixed-resolution, and coarse-grained models.

    PubMed

    Liao, Chenyi; Zhao, Xiaochuan; Liu, Jiyuan; Schneebeli, Severin T; Shelley, John C; Li, Jianing

    2017-03-20

    The structures and dynamics of protein complexes are often challenging to model in heterogeneous environments such as biological membranes. Herein, we meet this fundamental challenge at attainable cost with all-atom, mixed-resolution, and coarse-grained models of vital membrane proteins. We systematically simulated five complex models formed by two distinct G protein-coupled receptors (GPCRs) in the lipid-bilayer membrane on the ns-to-μs timescales. These models, which suggest the swinging motion of an intracellular loop, for the first time, provide the molecular details for the regulatory role of such a loop. For the models at different resolutions, we observed consistent structural stability but various levels of speed-ups in protein dynamics. The mixed-resolution and coarse-grained models show two and four times faster protein diffusion than the all-atom models, in addition to a 4- and 400-fold speed-up in the simulation performance. Furthermore, by elucidating the strengths and challenges of combining all-atom models with reduced resolution models, this study can serve as a guide to simulating other complex systems in heterogeneous environments efficiently.

  5. Monomeric mixed cadmium-2,2‧-dipyridylamine complex derived from ferrocenecarboxylic acid: Structural, electrochemical and biological studies

    NASA Astrophysics Data System (ADS)

    Senthilkumar, Kabali; Gopalakrishnan, Mohan; Palanisami, Nallasamy

    2015-09-01

    A mixed Cd(II) complex {[Cd(FcCOO)2(dpyam)(H2O)][Cd(dpyam)2 (H2O)2]·(ClO4)2·CH3OH} (1) (where FcCOO = ferrocenecarboxylic acid and dpyam = 2,2‧-dipyridylamine), has been synthesized and characterized by FT-IR, 1H & 13C NMR, UV-Vis spectroscopy and elemental analysis. The molecular structure of compound 1 has been determined by the single crystal X-ray diffraction technique, which consists of mixed two different cadmium(II) complexes and two uncoordinated perchlorate ions. The crystal packing shows that the compound 1 self-assembled by intermolecular hydrogen bonding via pyridyl N-H⋯O and coordinated water O⋯H-O-H⋯O, to afford the molecule 2D supramolecular network. Compound 1 exhibits high-energy intraligand (π-π∗) fluorescence emission. In electrochemical studies of compound 1 shows negative potential compared with ferrocenecarboxylic acid due to formation of coordination complex with Cd ions. The antibacterial study against the distinct bacterial strains show compound 1 has significant activity.

  6. Monomeric mixed cadmium-2,2'-dipyridylamine complex derived from ferrocenecarboxylic acid: Structural, electrochemical and biological studies.

    PubMed

    Senthilkumar, Kabali; Gopalakrishnan, Mohan; Palanisami, Nallasamy

    2015-09-05

    A mixed Cd(II) complex {[Cd(FcCOO)2(dpyam)(H2O)][Cd(dpyam)2 (H2O)2]·(ClO4)2·CH3OH} (1) (where FcCOO=ferrocenecarboxylic acid and dpyam=2,2'-dipyridylamine), has been synthesized and characterized by FT-IR, (1)H &(13)C NMR, UV-Vis spectroscopy and elemental analysis. The molecular structure of compound 1 has been determined by the single crystal X-ray diffraction technique, which consists of mixed two different cadmium(II) complexes and two uncoordinated perchlorate ions. The crystal packing shows that the compound 1 self-assembled by intermolecular hydrogen bonding via pyridyl N-H⋯O and coordinated water O⋯H-O-H⋯O, to afford the molecule 2D supramolecular network. Compound 1 exhibits high-energy intraligand (π-π(∗)) fluorescence emission. In electrochemical studies of compound 1 shows negative potential compared with ferrocenecarboxylic acid due to formation of coordination complex with Cd ions. The antibacterial study against the distinct bacterial strains show compound 1 has significant activity.

  7. X-ray absorption fine structure study of multinuclear copper(I) thiourea mixed ligand complexes

    NASA Astrophysics Data System (ADS)

    Gaur, Abhijeet; Shrivastava, B. D.; Srivastava, K.; Prasad, J.; Raghuwanshi, V. S.

    2013-07-01

    X-ray absorption fine structure spectra of five copper(I) thiourea complexes [Cu4(thu)6 (NO3)4 (H2O)4] (1), [Cu4(thu)9 (NO3)4 (H2O)4] (2), [Cu2(thu)6 (SO4) H2O] (3), [Cu2(thu)5 (SO4) (H2O)3] (4), and [Cu(thu)Cl 0.5H2O] (5) have been investigated. Complexes 1 and 3 are supposed to have one type of copper centers in trigonal planar and tetrahedral environment, respectively. Complexes 2 and 4 are supposed to have two types of copper centers, one center having trigonal planar geometry and another center having tetrahedral geometry. The aim of the present work is to show how extended X-ray absorption fine structure (EXAFS) spectra of these complexes, having different types of coordination environment, can be analyzed to yield the coordination geometry around one type of copper centers present in complexes 1 and 3, and two types of copper centers present in complexes 2 and 4. The crystal structure of complex 5 is unavailable due to inability of growing its single crystals, and hence the coordination geometry of this complex has been determined from EXAFS. The structural parameters determined from the EXAFS spectra have been reported and the coordination geometry has been depicted for the metal centers present in all the five complexes. Also, the chemical shifts have been used to determine the oxidation state of copper in these complexes. The X-ray absorption near edge spectra features have also been correlated with the coordination geometry. Also, the presence of both three and four coordinated Cu(I) centers in complexes 2 and 4 has been suggested from a comparison of the intensity of the feature at 8984 eV with those of 1 and 3. Further, in case of complex 5, the high intensity of peak A at 8986.5 eV is found to correspond to the presence of Cl coordinated to the copper center.

  8. The Grizzly Lake complex (Yellowstone Volcano, USA): Mixing between basalt and rhyolite unraveled by microanalysis and X-ray microtomography

    NASA Astrophysics Data System (ADS)

    Morgavi, Daniele; Arzilli, Fabio; Pritchard, Chad; Perugini, Diego; Mancini, Lucia; Larson, Peter; Dingwell, Donald B.

    2016-09-01

    Magma mixing is a widespread petrogenetic process. It has long been suspected to operate in concert with fractional crystallization and assimilation to produce chemical and temperature gradients in magmas. In particular, the injection of mafic magmas into felsic magma chambers is widely regarded as a key driver in the sudden triggering of what often become highly explosive volcanic eruptions. Understanding the mechanistic event chain leading to such hazardous events is a scientific goal of high priority. Here we investigate a mingling event via the evidence preserved in mingled lavas using a combination of X-ray computed microtomographic and electron microprobe analyses, to unravel the complex textures and attendant chemical heterogeneities of the mixed basaltic and rhyolitic eruption of Grizzly Lake in the Norris-Mammoth corridor of the Yellowstone Plateau volcanic field (YVF). We observe evidence that both magmatic viscous inter-fingering of magmas and disequilibrium crystallization/dissolution processes occur. Furthermore, these processes constrain the timescale of interaction between the two magmatic components prior to their eruption. X-ray microtomography images show variegated textural features, involving vesicle and crystal distributions, filament morphology, the distribution of enclaves, and further textural features otherwise obscured in conventional 2D observations and analyses. Although our central effort was applied to the determination of mixing end members, analysis of the hybrid portion has led to the discovery that mixing in the Grizzly Lake system was also characterized by the disintegration and dissolution of mafic crystals in the rhyolitic magma. The presence of mineral phases in both end member, for example, forsteritic olivine, sanidine, and quartz and their transport throughout the magmatic mass, by a combination of both mixing dynamics and flow imposed by ascent of the magmatic mass and its eruption, might have acted as a "geometric

  9. DNA interactions of cobalt(III) mixed-polypyridyl complexes containing asymmetric ligands.

    PubMed

    Wang, Xiang-Li; Chao, Hui; Li, Hong; Hong, Xian-Lan; Liu, Yun-Jun; Tan, Li-Feng; Ji, Liang-Nian

    2004-06-01

    Three novel asymmetric ligands, 3-(pyridine-2-yl)-5,6-diphenyl-as-triazine (pdtb), 3-(pyridine-2-yl)-as-triazino[5,6-f]acenaphthylene (pdta) and 3-(pyridine-2-yl)-as-triazino[5,6-f]phenanthroline (pdtp) and their cobalt(III) complexes have been synthesized and characterized. Binding of the three complexes with calf thymus DNA (CT-DNA) has been investigated by spectroscopic methods, viscosity, cyclic voltammetry, and electrophoresis measurements. The experimental results indicate that the size and shape of the intercalated ligand have a marked effect on the binding affinity of complexes to CT-DNA. Complexes 2 and 3 have also been found to promote cleavage of plasmid pBR322 DNA from the supercoiled form I to the open circular form II upon irradiation.

  10. A sandwich-type triple-decker lanthanide complex with mixed phthalocyanine and Schiff base ligands.

    PubMed

    Gao, Feng; Li, Yu-Yang; Liu, Cai-Ming; Li, Yi-Zhi; Zuo, Jing-Lin

    2013-08-21

    A new triple-decker dinuclear sandwich-type dysprosium complex based on both the phthalocyanine ligand and the tetradentate Schiff base ligand was synthesized, which is of interest for synthetic chemistry and also shows single-molecule magnetic behaviour.

  11. New organic-inorganic hybrid compounds constructed from polyoxometalates and transition metal mixed-organic-ligand complexes.

    PubMed

    Hu, Yang-Yang; Zhang, Ting-Ting; Zhang, Xiao; Zhao, De-Chuan; Cui, Xiao-Bing; Huo, Qi-Sheng; Xu, Ji-Qing

    2016-02-14

    Five new organic-inorganic hybrid compounds based on different polyoxoanions [HxGeW12O40](n-) or [H3As2W18O62](3-) (x = 0, 2; n = 4, 2), namely [Cu3(2,2'-bpy)3(inic)(OH)(H2O)][GeW12O40]·1.5H2O (1), [Cu2(phen)2(μ2-Cl)2(inic)]2[H2GeW12O40]·2H2O (2), [Cu2(phen)2(μ2-Cl)Cl(nic)]2[H2GeW12O40] (3), [Cu2(2,2'-bpy)2(hnic)Cl]2[H2GeW12O40] (4), [Cu(phen)(inic)H2O][Cu2(phen)2(inic)2(H2O)][H3As2W18O62]·3H2O (5) (inic = isonicotinic acid, nic = nicotinic acid, hnic = 2-hydroxy-nicotinic acid, 2,2'-bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline), have been synthesized and characterized by IR, UV-Vis, XRD, cyclic voltammetric measurements and single crystal X-ray diffraction analysis. Single crystal X-ray analysis reveals that compound 1 is isomorphous and isostructural with a compound reported by us recently, the main difference between the two is the heteroatom of the polyoxoanions in the two compounds. Compound 2 is a supramolecular structure constructed from polyoxoanions and transition metal mixed-organic-ligand complexes. Compound 3 is a novel polyoxoanion bi-supported transition metal mixed-organic-ligand complex. Compound 4 is a 1-D chain structure constructed from polyoxoanions and transition metal mixed-organic-ligand complexes. The photodegradation properties of compounds 1-5 have been analyzed.

  12. Optically active mixed (phthalocyaninato)(porphyrinato) rare earth triple-decker complexes. Synthesis, spectroscopy, and effective chiral information transfer.

    PubMed

    Lu, Jitao; Deng, Yanhua; Zhang, Xiaomei; Kobayashi, Nagao; Jiang, Jianzhuang

    2011-03-21

    With the view to creating novel sandwich-type tetrapyrrole rare earth complexes toward potential applications in material science and chiral catalysis, two new optically active mixed (phthalocyaninato)(porphyrinato) rare earth triple-decker complexes with both (R)- and (S)-enantiomers [M(2)(Pc)(2)(TCBP)] {TCBP = Meso-tetrakis [3,4-(11,12:13,14-di(1',2'-naphtho)-1,4,7,10,15,18-hexaoxacycloeicosa-2,11,13-triene)-phenyl] porphyrinate; M = Eu (1), Y (2)} have been designed and prepared by treating optically active metal free porphyrin (R)-/(S)-H(2)TCBP with M(Pc)(2) in the presence of corresponding M(acac)(3)·nH(2)O (acac = acetylacetonate) in refluxing 1,2,4-trichlorobenzene (TCB). These novel mixed ring rare earth triple-decker compounds were characterized by a wide range of spectroscopic methods including MS, (1)H NMR, IR, electronic absorption, and magnetic circular-dichroism (MCD) spectroscopic measurements in addition to elemental analysis. Perfect mirror image relationship was observed in the Soret and Q absorption regions in the circular-dichroism (CD) spectra of the (R)- and (S)-enantiomers, indicating the optically active nature of these two mixed (phthalocyaninato)(porphyrinato) rare earth triple-decker complexes. This result reveals the effective chiral information transfer from the peripheral chiral binaphthyl units to the porphyrin and phthalocyanine chromophores in the triple-decker molecule because of the intense π-π interaction between porphyrin and phthalocyanine rings. In addition, their electrochemical properties have also been investigated by cyclic voltammetry (CV).

  13. Studies on Photocleavage, DNA Binding, Cytotoxicity, and Docking Studies of Ruthenium(II) Mixed Ligand Complexes.

    PubMed

    Kumar, Yata Praveen; Devi, C Shobha; Srishailam, A; Deepika, N; Kumar, V Ravi; Reddy, P Venkat; Nagasuryaprasad, K; Singh, Surya S; Nagababu, Penumaka; Satyanarayana, S

    2016-11-01

    This article describes the synthesis and characterization of three new Ru(II) polypyridyl complexes including [Ru(phen)2(dpphz)](2+) (1), [Ru(bpy)2(dpphz)](2+) (2) and [Ru(dmb)2(dpphz)](2+) (3) where dpphz = dipyrido[3,2-a:2',3'-c] phenazine-11-hydrazide, phen =1,10-phenanthroline, bpy = 2,2'-bipyridine and dmb = 4,4'-dimethyl2,2'-bipyridine. The binding behaviors of these complexes to calf thymus DNA (CT-DNA) were explored by spectroscopic titrations, viscosity measurements. Results suggest that these complexes can bind to CT-DNA through intercalation. However, their binding strength differs from each other; this may be attributed to difference in the ancillary ligand. The cytotoxicity of 1-3 was evaluated by MTT assay; results indicated that all complexes have significant dose dependent cytotoxicity with HeLa tumor cell line. All complexes exhibited efficient photocleavage of pBR322 DNA upon irradiation. The DNA binding ability of 1-3 was also studied by docking the complexes into B-DNA using docking program.

  14. Synthesis, electronic, photoacoustic and electron spin resonance investigations on some tetrathiocyanate binuclear mixed-metal complexes

    NASA Astrophysics Data System (ADS)

    Singh, Raghuvir

    Complexes of the type M 1M 2(SCN) 4xL[M 1 = Ni(II); M 2 = Cd(II) and Hg(II) and L = pyridine, morpholine, dioxan, benzo(f)quinoline, 2,2'-bipyridine, 2,2'-bipyridine N, N'-dioxide, isonicotinic acid hydrazide and 1,10-phenanthroline: x = 2 or 4] have been synthesized and characterized by chemical analysis, magnetic susceptibility, infrared, electronic and photoacoustic (PAS) spectra as well as electron spin resonance (ESR) spectral studies in the solid and solution state. The different coordination sites have been investigated in these ligands towards metal coordination and the behaviour of thiocyanate anions studied. Electron spin resonance spectral data for copper complexes show the distorted octahedral stereochemistry around copper(II) in these complexes. The parameters such as g∥, g⊥, A∥, A⊥, < g>, < A> and α 2 calculated for the copper complexes from their ESR spectra indicate the presence of unpaired electron in d x2- y2 or d z2 orbitals. The photoacoustic and electronic spectra of these complexes were studied in the solid state to see the nature of thiocyanate and overall symmetry of the complexes. The results on electronic and photoacoustic spectral studies are in good agreement with ESR data.

  15. Disequilibrium phenocryst textures in an Andean volcanic complex: mixing or rapid decompression?

    NASA Astrophysics Data System (ADS)

    Feineman, M. D.; Sruoga, P.; Drew, D.; Murray, T.

    2010-12-01

    Mantle-derived magmas of the Andean Central Volcanic Zone and northern Southern Volcanic Zone pass through >50 km of continental crust prior to eruption. Geochemical and geophysical evidence suggests that these magmas pause in both the lower and upper crust prior to eruption. As upper crustal magma chambers must be periodically replenished from deep-rooted magma sources, it is reasonable to expect some degree of cyclical magma mixing over the life span of a volcano. Lavas erupted from Maipo Volcano in the northern Southern Volcanic Zone display cyclical variability in silica content from 54% to 68% over its 86 Ka eruptive history to date. Disequilibrium phenocryst textures, including sieve-textured plagioclase, embayed and anhedral phenocrysts, oxidized horblende rims, and olivine phenocrysts with orthopyroxene overgrowths are ubiquitous. While these disequilibrium features are characteristic of magma mixing, many of these could also be brought on by rapid magma ascent, which changes the position of the liquidus relative to the crystallizing assemblage. Some of the most primitive lavas found at Maipo are the 28 (±17) Ka basaltic andesites (SiO2 = 57-61%; 87Sr/86Sr = 0.7049), constituting the fourth of seven major eruptive events. These lavas appear to emanate from the base of the eastern flank and are found only on the caldera floor, suggesting a lateral or fissure eruption. The location and relatively primitive nature of the Event IV lavas may be interpreted as indicating that they have bypassed extensive interaction (i.e., mixing) with magmas in the main upper crustal chamber. However, basaltic andesites of comparable composition (SiO2 = 53-59%, 87Sr/86Sr = 0.7048) are also associated with the ultimate (potentially historic) Event VII, consisting of scoria bombs sampled within and emanating from the central crater. While it is unlikely that these lavas could have bypassed the shallow magma chamber, it is conceivable that these flows tap a deep, relatively

  16. Computational studies of penetration and mixing for complex jet injectors to aid in design of hypersonic systems

    NASA Astrophysics Data System (ADS)

    Campioli, Theresa Lynn

    A computational study of sonic light-gas jet injection into a supersonic cross flow was conducted. The scope of the numerical analysis encompassed many studies that affect how the flow-field is numerically modeled and the behavior, specifically mixing, of the flow-field itself. A single, round injector was used for the Baseline design. Simulated conditions involved sonic injection of helium heated to 313 K into a Mach 4 air cross-stream with average Reynolds number 5.77 e+7 per meter and a freestream momentum flux ratio of 2.1. Experiments at these conditions were available for comparison. The primary numerical flow solver employed was GASP v. 4.2. The Menter Shear Stress Transport (SST) turbulence model was used, since the algorithm has good capability of solving both wall-bounded and free-shear flows. The SST model was able to capture the mixing behavior of the complex flow-field. Important numerical parameters that affect the capabilities of the numerical solver were studied for the Baseline injector. These sensitivity studies varied the choice of turbulent Prandtl number, Schmidt number, freestream turbulence intensity, boundary layer size, steady and unsteady approaches and computational software packages. A decrease in the turbulent Prandtl number resulted in better mixing behavior of the prediction and better agreement with the experiment. An increase in the turbulent Schmidt number had a small adverse effect on the predictions. The mixing characteristics remained constant with an increase in freestream turbulence intensity. The best Baseline prediction was then compared to three different injector configurations: an aerodynamic ramp consisting of four injectors in an array, a diamond injector both aligned and yawed 15° to the oncoming flow. The Computational Fluid Dynamics (CFD) tools were more accurate compared to experiment in the prediction of the aeroramp injector than the diamond-shaped injectors. The aeroramp injector slightly improved mixing

  17. Mixed ligand Cu(II)N2O2 complexes: biomimetic synthesis, activities in vitro and biological models, theoretical calculations.

    PubMed

    Li, Chen; Yin, Bing; Kang, Yifan; Liu, Ping; Chen, Liang; Wang, Yaoyu; Li, Jianli

    2014-12-15

    Three new mixed ligand Cu(II)N2O2 complexes, namely, [Cu(II)(2-A-6-MBT)2(m-NB)2] (1), [Cu(II)(2-ABT)2(m-NB)2] (2), and [Cu(II)(2-ABT)2(o-NB)2] (3), (2-A-6-MBT = 2-amino-6-methoxybenzothiazole, m-NB = m-nitrobenzoate, 2-ABT = 2-aminobenzothiazole, and o-NB = o-nitrobenzoate), have been prepared by the biomimetic synthesis strategy, and their structures were determined by X-ray crystallography studies and spectral methods. These complexes exhibited the effective superoxide dismutase (SOD) activity and catecholase activity. On the basis of the experimental data and computational studies, the structure-activity relationship for these complexes was investigated. The results reveal that electron-accepting abilities of these complexes and coordination geometries have significant effects on the SOD activity and catecholase activity. Then, we found that 1 and 2 exerted potent intracellular antioxidant capacity in the model of H2O2-induced oxidative stress based on HeLa cervical cancer cells, which were screened out by the cytotoxicity assays of different kinds of cells. Furthermore, 1-3 showed the favorable biocompatibility in two different biological models: Saccharomyces cerevisiae and human vascular endothelial cells. These biological experimental data are indicative of the promising application potential of these complexes in biology and pharmacology.

  18. Theoretical studies on vibrational spectra of mixed cyanide-halide complexes of platinum(IV) and palladium(IV)

    NASA Astrophysics Data System (ADS)

    Zhang, Yu; Zhang, Lin; Tao, Hanbing; Sun, Xiaojuan; Zhu, Longgen

    2003-02-01

    The vibrational spectra of mixed cyanide-halide complexes, M(CN) 4X 22- and M(CN) 5X 2- (M=Pt and Pd; X=F, Cl, Br and I), have been systematically investigated by ab initio RHF, B3LYP and MP2 methods with LanL2DZ and SDD basis sets. The calculated vibrational frequencies of platinum complexes are evaluated via comparison with the experimental values. In the infrared frequency region, the CN stretching vibrational frequencies calculated at B3LYP level with two basis sets are in good agreement with the observed values with deviations, -16-4 cm -1 for Pt(CN) 4X 22- and -18 to -2 cm -1 for Pt(CN) 5X 2-. However, in far-infrared region, the results obtained at RHF level are better than those calculated at B3LYP and MP2 levels. For RHF/SDD method, the deviations for PtX and PtC stretching vibrational frequencies are -14-1 and -12 to -2 cm -1 in the complex Pt(CN) 4X 22-, -19 to -11 and -15-14 cm -1 in the Pt(CN) 5X 2- complex, respectively. The vibrational frequencies of palladium(IV) and some platinum(IV) complexes that have not been experimentally reported are predicted.

  19. Environmental assessment: Solid waste retrieval complex, enhanced radioactive and mixed waste storage facility, infrastructure upgrades, and central waste support complex, Hanford Site, Richland, Washington

    SciTech Connect

    1995-09-01

    The U.S. Department of Energy (DOE) needs to take action to: retrieve transuranic (TRU) waste because interim storage waste containers have exceeded their 20-year design life and could fail causing a radioactive release to the environment provide storage capacity for retrieved and newly generated TRU, Greater-than-Category 3 (GTC3), and mixed waste before treatment and/or shipment to the Waste Isolation Pilot Project (WIPP); and upgrade the infrastructure network in the 200 West Area to enhance operational efficiencies and reduce the cost of operating the Solid Waste Operations Complex. This proposed action would initiate the retrieval activities (Retrieval) from Trench 4C-T04 in the 200 West Area including the construction of support facilities necessary to carry out the retrieval operations. In addition, the proposed action includes the construction and operation of a facility (Enhanced Radioactive Mixed Waste Storage Facility) in the 200 West Area to store newly generated and the retrieved waste while it awaits shipment to a final disposal site. Also, Infrastructure Upgrades and a Central Waste Support Complex are necessary to support the Hanford Site`s centralized waste management area in the 200 West Area. The proposed action also includes mitigation for the loss of priority shrub-steppe habitat resulting from construction. The estimated total cost of the proposed action is $66 million.

  20. The analysis of complex mixed-radiation fields using near real-time imaging.

    PubMed

    Beaumont, Jonathan; Mellor, Matthew P; Joyce, Malcolm J

    2014-10-01

    A new mixed-field imaging system has been constructed at Lancaster University using the principles of collimation and back projection to passively locate and assess sources of neutron and gamma-ray radiation. The system was set up at the University of Manchester where three radiation sources: (252)Cf, a lead-shielded (241)Am/Be and a (22)Na source were imaged. Real-time discrimination was used to find the respective components of the neutron and gamma-ray fields detected by a single EJ-301 liquid scintillator, allowing separate images of neutron and gamma-ray emitters to be formed. (252)Cf and (22)Na were successfully observed and located in the gamma-ray image; however, the (241)Am/Be was not seen owing to surrounding lead shielding. The (252)Cf and (241)Am/Be neutron sources were seen clearly in the neutron image, demonstrating the advantage of this mixed-field technique over a gamma-ray-only image where the (241)Am/Be source would have gone undetected.

  1. Parametric analysis of a complex flow: a mixing layer- wake interaction

    NASA Astrophysics Data System (ADS)

    Braud, Caroline; Heitz, Dominique

    2004-11-01

    The flow studied is a cross interaction from two canonical flows, a wake and a mixing layer, realized for the first time by Heitz(1999) for a particular configuration (Reynolds number 7, 500, aspect ratio 18, shear parameter 0.42). He found that the difference of velocity between two sides of the mixing layer gives rise to a pressure gradient along the cylinder responsible for a secondary flow from the low to high velocity side in the near wake. As a consequence the suction coefficient (C_p), the frequency distribution (f) and the vortex length formation (L_f) are locally greatly modified if we compare them to uniform flow. Nevertheless, the aspect ratio, according to Norberg (1994), and the shear parameter (in uniform shear wake: 0.02) are control parameters of great importance for the shedding organization in the near wake. In order to investigate the influence of those control parameters (Reynolds numbers, two aspects ratio and five shear parameters) hot wire and pressure measurement have been carried out. We mainly found that even if the magnitude of the mean characteristic parameters is locally strongly perturbated along the cylinder, the resulting wake keeps its general behavior.

  2. Clasts in the CM2 carbonaceous chondrite Lonewolf Nunataks 94101: Evidence for aqueous alteration prior to complex mixing

    NASA Astrophysics Data System (ADS)

    Lindgren, Paula; Lee, Martin R.; Sofe, Mahmood R.; Zolensky, Michael E.

    2013-06-01

    Clasts in the CM2 carbonaceous chondrite Lonewolf Nunataks (LON) 94101 have been characterized using scanning and transmission electron microscopy and electron microprobe analysis to determine their degrees of aqueous alteration, and the timing of alteration relative to incorporation of clasts into the host. The provenance of the clasts, and the mechanism by which they were incorporated and mixed with their host material are also considered. Results show that at least five distinct types of clasts occur in LON 94101, of which four have been aqueously altered to various degrees and one is largely anhydrous. The fact that they have had different alteration histories implies that the main part of aqueous activity occurred prior to the mixing and assimilation of the clasts with their host. Further, the presence of such a variety of clasts suggests complex mixing in a dynamic environment involving material from various sources. Two of the clasts, one containing approximately 46 vol% carbonate and the other featuring crystals of pyrrhotite up to approximately 1 mm in size, are examples of unusual lithologies and indicate concentration of chemical elements in discrete areas of the parent body(ies), possibly by flow of aqueous solutions.

  3. Mixing and chemical interdiffusion of trachytic and latitic magma in a subvolcanic complex of the Tertiary Westerwald (Germany)

    NASA Astrophysics Data System (ADS)

    Schreiber, Ulrich; Anders, Dirk; Koppen, Joachim

    1999-04-01

    A special kind of magma mixing is extraordinarily well exposed in the Bittersberg subvolcanic complex in the Tertiary volcanic field of the German Westerwald: A trachytic melt has been penetrated by a latitic dyke which has been dispersed within the host magma as small spherical enclaves (globules). Whole rock analyses of the globules show a change in composition that cannot be explained by a simple mechanical mixing between the endmembers. The most evolved globules have a phonolitic composition. Microprobe measurements in the microlithic matrix of the host rock and the guest indicate a diffusive motion of the alkalis from the host into the globules. On the other hand, an opposite trend can be observed for Ca, Mg, Fe and Ti, which are impoverished in the globules. The trace elements and the middle rare earth elements (MREE) has also been involved in the diffusive exchange. The REE-pattern of the most evolved (phonolitic) globules shows a characteristic trough in the area of the MREE which is almost identical to the REE-pattern of many phonolites. The phonolites and the alkali-rich trachytes of the Westerwald show similar globular textures as the Bittersberg volcanics. Therefore, generation of these rocks involving diffusive element exchange during mixing processes in a magma reservoir situated on a deeper crustal level may be possible.

  4. Final Report of the Grant: ''Vertical Transport and Mixing in Complex Terrain Airsheds''

    SciTech Connect

    Fernando, Joseph Harindra; Anderson, James; Boyer, Don; Berman, Neil

    2004-12-29

    Stable stratification associated with nocturnal thermal circulation in areas of complex terrain leads to interesting and important phenomena that govern local meteorology and contaminant dispersion. Given that most urban areas are in complex topography, understanding and prediction of such phenomena are of immediate practical importance. This project dealt with theoretical, laboratory, numerical and field experimental studies aimed at understanding stratified flow and turbulence phenomena in urban areas, with particular emphasis on flow, turbulence and contaminant transport and diffusion in such flows. A myriad of new results were obtained and some of these results were used to improve the predictive capabilities of the models.

  5. Recharge mixing in a complex distributary spring system in the Missouri Ozarks, USA

    USDA-ARS?s Scientific Manuscript database

    Toronto Springs is a complex distributary karst spring system with 11 perennial springs in the central Missouri Ozarks, USA. Carroll Cave (CC) and Wet Glaize Creek (WG) were previously identified as principal recharge sources. This study 1) characterized physical and chemical properties of the sprin...

  6. Combined LDV and Rayleigh measurements in a complex turbulent mixing flow

    NASA Astrophysics Data System (ADS)

    de Groot, W. A.; Walterick, R. E.; Jagoda, J. I.

    1987-06-01

    Velocities and bleed gas concentrations of the cold flow over a backward facing step with bleeding from the wall behind the step was measured by an LDV/Rayleigh-scattering technique to study the flow field in the flame stabilization region in a solid-fueled ramjet. A reduction technique was used in which the background noise due to glare, electronic noise, and scattering due to seed particles was removed from the Rayleigh scattering signal. Good agreement was found between the experimental results and results from an analytical model based upon a modified k-epsilon code, although the model was found to underpredict the mixing downstream of reattachment, and to overpredict the velocity-concentration covariance.

  7. Major Histocompatibilty Complex-Restricted Adaptive Immune Responses to CT26 Colon Cancer Cell Line in Mixed Allogeneic Chimera.

    PubMed

    Lee, K W; Choi, B; Kim, Y M; Cho, C W; Park, H; Moon, J I; Choi, G-S; Park, J B; Kim, S J

    2017-06-01

    Although the induction of mixed allogeneic chimera shows promising clinical tolerance results in organ transplantation, its clinical relevance as an anti-cancer therapy is yet unknown. We introduced a mixed allogenic chimera setting with the use of a murine colon cancer cell line, CT26, by performing double bone marrow transplantation. We analyzed donor- and recipient-restricted anti-cancer T-cell responses, and phenotypes of subpopulations of T cells. The protocol involves challenging 1 × 10(5) cells of CT26 cells intra-hepatically on day 50 after bone marrow transplantation, and, by use of CT26 lysates and an H-2L(d)-restricted AH1 pentamer, flow cytometric analysis was performed to detect the generation of cancer-specific CD4(+) and CD8(+) T cells at various time points. We found that immunocompetence against tumors depends heavily on cancer-specific CD8(+) T-cell responses in a major histocompatibility complex-restricted manner; the evidence was further supported by the increase of interferon-γ-secreting CD4(+) T cells. Moreover, we demonstrated that during the effector immune response to CT26 cancer challenge, there was a presence of central memory cells (CD62L(hi)CCR7(+)) as well as effector memory cells (CD62L(lo)CCR7(-)). Moreover, mixed allogeneic chimeras (BALB/c to C56BL/6 or vice versa) showed similar or heightened immune responses to CT26 cells compared with that of wild-type mice. Our results suggest that the responses of primary immunocompetency and of pre-existing memory T cells against allogeneic cancer are sustained and preserved long-term in a mixed allogeneic chimeric environment. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Membrane-surfactant interactions. The role of surfactant in mitochondrial complex III-phospholipid-Triton X-100 mixed micelles

    SciTech Connect

    Valpuesta, J.M.; Arrondo, J.L.; Barbero, M.C.; Pons, M.; Goni, F.M.

    1986-05-15

    Complex III (ubiquinol-cytochrome c reductase) was purified from beef heart mitochondria in the form of protein-phospholipid-Triton X-100 mixed micelles (about 1:80:100 molar ratio). Detergent may be totally removed by sucrose density gradient centrifugation, and the resulting lipoprotein complexes retain full enzyme activity. In order to understand the role of surfactant in the mixed micelles, and the interaction of Triton X-100 with integral membrane proteins and phospholipid bilayers, both the protein-lipid-surfactant mixed micelles and the detergent-free lipoprotein system were examined from the point of view of particle size and ultrastructure, enzyme activity, tryptophan fluorescence quenching, 31P NMR, and Fourier transform infrared spectroscopy. The NMR and IR spectroscopic studies show that surfactant withdrawal induces a profound change in phospholipid architecture, from a micellar to a lamellar-like phase. However, electron microscopic observations fail to reveal the existence of lipid bilayers in the absence of detergent. We suggest that, under these conditions, the lipid:protein molar ratio (80:1) is too low to permit the formation of lipid bilayer planes, but the relative orientation and mobility of phospholipids with respect to proteins is similar to that of the lamellar phase. Protein conformational changes are also detected as a consequence of surfactant removal. Fourier transform infrared spectroscopy indicates an increase of peptide beta-structure in the absence of Triton X-100; changes in the amide II/amide I intensity ratio are also detected, although the precise meaning of these observations is unclear.

  9. Vanadium complexes with mixed O,S anionic ligands derived from maltol: synthesis, characterization, and biological studies.

    PubMed

    Monga, Vishakha; Thompson, Katherine H; Yuen, Violet G; Sharma, Vijay; Patrick, Brian O; McNeill, John H; Orvig, Chris

    2005-04-18

    Four mixed O,S binding bidentate ligand precursors derived from maltol (3-hydroxy-2-methyl-4-pyrone) have been chelated to vanadium to yield new bis(ligand)oxovanadium(IV) and tris(ligand)vanadium(III) complexes. The four ligand precursors include two pyranthiones, 3-hydroxy-2-methyl-4-pyranthione, commonly known as thiomaltol (Htma), and 2-ethyl-3-hydroxy-4-pyranthione, commonly known as ethylthiomaltol (Hetma), as well as two pyridinethiones, 3-hydroxy-2-methyl-4(H)-pyridinethione (Hmppt) and 3-hydroxy-1,2-dimethyl-4-pyridinethione (Hdppt). Vanadium complex formation was confirmed by elemental analysis, mass spectrometry, and IR and EPR (where possible) spectroscopies. The X-ray structure of oxobis(thiomaltolato)vanadium(IV),VO(tma)(2), was also determined; both cis and trans isomers were isolated in the same asymmetric unit. In both isomers, the two thiomaltolato ligands are arranged around the base of the square pyramid with the V=O linkage perpendicular; the vanadium atom is slightly displaced from the basal plane [V(1) = 0.656(3) A, V(2) = 0.664(2) A]. All of the new complexes were screened for insulin-enhancing effectiveness in streptozotocin-induced diabetes in rats, and VO(tma)(2) was profiled metabolically for urinary vanadium and ligand clearance by GFAAS and ESIMS, respectively. The new vanadium complexes did not lower blood glucose levels acutely, possibly because of rapid dissociation and excretion.

  10. Synthesis and characterization of oxo-bridged, trinuclear, six-coordinate mixed-carboxylato complexes of chromium (III)

    NASA Astrophysics Data System (ADS)

    Baranwal, B. P.; Fatma, Talat

    2005-08-01

    Mixed-carboxylato β-diketonato complexes of chromium (III) (R=C13H27, C15H31 or C17H35 and L=CH3OH) [Cr3O(OOCR)3(dike)3L3]+ have been synthesized by enforced substitution reactions of [Cr3O(OOCCH3)7(H2O)] first with straight chain fatty acids (myristic, palmitic or stearic acid) and then with β-diketones (Hβ-dike) like acetylacetone(Hacac) or benzoylacetone(Hbzac) in toluene under reflux. These are new type of oxo-bridged chromium(III) complexes in which one ligand is a fatty acid while the other one is a β-diketone. The complexes were characterized by elemental analyses, spectral (infrared, electronic, FAB mass and powder XRD) studies, molar conductance and magnetic susceptibility measurements. Bridging coordination modes for both carboxylate and β-diketonate anions were indicated by presence of νasym(Cr3O) vibrations in the infrared spectra. Trinuclear nature of the complexes and their structural features have been discussed on the basis of physicochemical studies.

  11. Mixed sandwich thorium complexes incorporating bis(tri-isopropylsilyl)cyclooctatetraenyl and pentamethylcyclopentadienyl ligands: synthesis, structure and reactivity.

    PubMed

    Button, Zoë E; Higgins, Jessica A; Suvova, Markéta; Cloke, F Geoffrey N; Roe, S Mark

    2015-02-14

    The Th(iv) mixed-sandwich halide complexes Th(COT(TIPS2))Cp*X (where COT(TIPS2) = 1,4-{Si(i)Pr(3)}(2)C(8)H(6), X = Cl, I) have been synthesised, and structurally characterised. When Th(COT(TIPS2))Cp*I is reduced in situ in the presence of CO(2), a mixture of dimeric carboxylate and oxalate complexes {Th(COT(TIPS2))Cp*}(2)(μ-κ(1):κ(2)-CO(3)) and {Th(COT(TIPS2))Cp*}(2)(μ-κ(2):κ(2)-C(2)O(4)) are formed, possibly via a transient Th(iii) species. Th(COT(TIPS2))Cp*Cl is readily alkylated to yield the benzyl complex Th(COT(TIPS2))Cp*CH(2)Ph, which reacts with CO(2) to form a carboxylate and with H(2) to form a hydride; the latter inserts CO(2), giving the bridging formate complex {Th(COT(TIPS2))Cp*(μ-κ(1):κ(1)-O(2)CH)}(2).

  12. Eruption-triggered mixing of extra-caldera basalt and rhyolite complexes along the East Gallatin-Washburn fault zone, Yellowstone National Park, WY, USA

    NASA Astrophysics Data System (ADS)

    Pritchard, C. J.; Larson, P. B.; Spell, T. L.; Tarbert, K. D.

    2013-08-01

    Though mixing and commingling of magmas is common, mixing between rhyolite and basalt magmas is not commonly preserved in volcanic rocks. The presence of at least four mixed magma complexes at Yellowstone National Park suggests that mingling is not due to random intersections of feeder dikes, geochemical analyses also show that though these magmas appear to be commingled, there is mixing between the two disparate end members. Our model combines previous work on the Grizzly Lake, Gardner River, Crystal Spring, and Appolinaris Spring mixed magma complexes with results from new analyses, recent mixing experiments, and regional structural geology. Coeval extensional tectonism, as seen in the East Gallatin-Washburn fault zone, is also present in other areas of basalt and rhyolite mixing/mingling (e.g. Iceland). The central portions, or core, of the complexes contain increased concentrations of emulsion rock, occasional basaltic pillows in a rhyolite matrix, net veining, and mixed magma with highly variable geochemistry (SiO2 ranges from 50 to 78 wt.%). Phenocrysts have been transferred between mafic and felsic portions of the complexes and suggest that these mixed magmas did not have enough time, or energy (e.g. heat), to thoroughly mix into complete hybrid intermediate magmas. This implies that mixing occurred during eruption. Furthermore, analyses at the micron-scale suggest that zones of chaotic mixing between basalt and high-silica rhyolites may be more complete than previously thought during mixing of high silica rhyolites and basalts with greater than 4 wt.% MgO. The temperature of the rhyolitic magmas was approximately 850 °C with a viscosity between 1 × 106 and 3 × 106 Pas. The basalt was approximately 1070 °C with a viscosity of 2 × 102 to 9 × 103 Pas prior to mixing. Mixing of these two extreme end members may have required decompression of the lower basaltic magma chamber during eruption of the overlying rhyolitic magma chamber into through structurally

  13. Communication: Physical origins of ionization potential shifts in mixed carboxylic acids and water complexes

    NASA Astrophysics Data System (ADS)

    Gu, Quanli; Tang, Zhen; Su, Peifeng; Wu, Wei; Yang, Zhijun; Trindle, Carl O.; Knee, Joseph L.

    2016-08-01

    The ionization potential (IP) of the aromatic alpha hydroxy carboxylic acid, 9-hydroxy-9-fluorene carboxylic acid (9HFCA), is shifted by complexation with hydrogen bonding ligands such as water and formic acid. Generalized Kohn-Sham energy decomposition analysis decomposes the intermolecular binding energies into a frozen energy term, polarization, correlation, and/or dispersion energy terms, as well as terms of geometric relaxation and zero point energy. We observe that in each dimer the attractive polarization always increases upon ionization, enhancing binding in the cation and shifting the IP toward the red. For 9HFCA—H2O, a substantial decrease of the repulsive frozen energy in cation further shifts the IP toward red. For 9HFCA—HCOOH, the increase of the frozen energy actually occurs in the cation and shifts the IP toward blue. Consistent with the experimental measurements, our analysis provides new, non-intuitive perspectives on multiple hydrogen bonds interactions in carboxylic acids and water complexes.

  14. Preliminary observation of complex salt-fresh water mixing in a beach aquifer.

    PubMed

    Thorn, Paul; Urish, Daniel

    2013-01-01

    Continuous observations of beach groundwater salinity over a 35-d period from a monitoring well established in the intertidal zone of a coastal harbor provided intriguing data on the interaction in the intertidal zone between the salt and fresh groundwater. During the monitoring period of the study, both semidiurnal variations and longer temporal trends in groundwater salinity were observed. The semidiurnal salinity variations were observed to occur nearly synchronously, but inconsistently with the tides. However, the salinity relationship with the tides was more complex, switching back and forth from being in-sync (higher salinities at high tide) to out-of-sync (higher salinities at low tide) a total of four times during the 35-d test period. The longer temporal trends showed chloride concentration (representing salinity) varying from as low as 50 mg/L to as high as 3600 mg/L over a period of between 9 to 12 d. The observations from the monitoring well reveal a complex pattern likely resulting from a combination of tidal pumping, density-induced convection, and changes in the terrestrial hydraulic gradient. However, these observations are based upon data from only one monitoring well, and are speculative at this point. A more thorough study of the complex fresh water-saline water relationship in the intertidal zone seems to have merit. © 2012, The Author(s). Ground Water © 2012, National Ground Water Association.

  15. The role of magma mixing in the petrogenesis of mafic alkaline lavas, Rockeskyllerkopf Volcanic Complex, West Eifel, Germany

    NASA Astrophysics Data System (ADS)

    Shaw, Cliff S. J.; Woodland, Alan B.

    2012-03-01

    The quaternary Rockeskyllerkopf Volcanic Complex (RVC) comprises three spatially and temporally distinct volcanic centers that can also be distinguished on the basis of their geochemical signatures. All the volcanic products in the complex are olivine basanites whose major and trace element compositions span almost the entire range defined for the West Eifel field as a whole. The RVC lavas have lower Al2O3, Na2O and Y contents and higher TiO2, CaO, K2O, Sc, V, Co, Rb, and Ba than the Tertiary lavas in nearby Hocheifel volcanic field. Within the complex, the oldest South East Lammersdorf Center (SEL) comprises primitive lavas with an average MgO content of ˜11 wt.% and LaN/YbN of 29 ± 2. The second center, Mäuseberg, has similar MgO to SEL but is distinct in its much higher LaN/YbN of 42 ± 2. The Rockeskyllerkopf Center, which was erupted after a break in activity, comprises lavas similar in composition to the SEL Center but with distinctly higher Al2O3 and lower MgO contents. Given the lack of evidence for significant fractionation or assimilation in the RVC lavas, we attribute the compositional variations within and between the centers of the RVC to be due to variations in the composition of the source region in combination with magma mixing. Our preferred model involves 1-5% partial melting of LREE-enriched mantle in the garnet stability field, likely within the thermal boundary layer at the base of the lithospheric mantle. These melts mixed to variable degrees with 2-4% partial melts of phlogopite-spinel peridotite formed at higher levels in the modally metasomatised lithospheric mantle.

  16. Complex catalytic behaviors of CuTiOx mixed-oxide during CO oxidation

    DOE PAGES

    Kim, Hyun You; Liu, Ping

    2015-09-21

    Mixed metal oxides have attracted considerable attention in heterogeneous catalysis due to the unique stability, reactivity, and selectivity. Here, the activity and stability of the CuTiOx monolayer film supported on Cu(111), CuTiOx/Cu(111), during CO oxidation was explored using density functional theory (DFT). The unique structural frame of CuTiOx is able to stabilize and isolate a single Cu+ site on the terrace, which is previously proposed active for CO oxidation. Furthermore, it is not the case, where the reaction via both the Langmuir–Hinshelwood (LH) and the Mars-van Krevelen (M-vK) mechanisms are hindered on such single Cu+ site. Upon the formation ofmore » step-edges, the synergy among Cuδ+ sites, TiOx matrix, and Cu(111) is able to catalyze the reaction well. Depending on temperatures and partial pressure of CO and O2, the surface structure varies, which determines the dominant mechanism. In accordance with our results, the Cuδ+ ion alone does not work well for CO oxidation in the form of single sites, while the synergy among multiple active sites is necessary to facilitate the reaction.« less

  17. Mixing Induced By Slope and Valley Flow Collisions in Complex Terrain

    NASA Astrophysics Data System (ADS)

    Fernando, H. J.; Hocut, C. M.; Zhong, Q.; Hoch, S.; Leo, L.; Di Sabatino, S.; Pardyjak, E.; Whiteman, C. D.

    2014-12-01

    A fascinating observation made during the fall 2012 field campaign of the Mountain Terrain Atmospheric Modeling and Observations Program (MATERHORN) was the collision of slope and valley flows that led to powerful but spasmodic turbulence generating events. The contributions of these collisions to overall basin (meso) scale mixing were studied using the MATERHORN field data as well as laboratory measurements conducted under controlled conditions using counter flowing gravity currents. The collisions cause localized shear layers and Kelvin Helmholtz billowing, which, together with turbulence generated by impingement of fronts on one another, generate a turbulence field that decays rapidly under local stable stratification. Buoyancy fluxes measured using these events are parameterized in terms of a suitably defined Richardson number and dimensionless geometric parameters. The time and lengthscales of initial turbulence as well as its decay time scale are measured and quantified using governing parameters. Mechanisms responsible for the recurrence of collision events are elicited based on data from a large number of flux towers, remote sensors and infrared cameras located in the domain of observations.

  18. Complex serpentinizing systems and the deep biosphere: metabolic opportunities depend on the geochemistry of mixing waters

    NASA Astrophysics Data System (ADS)

    Cardace, D.; Meyer-Dombard, D. R.; Hoehler, T. M.; Uzunlar, N.

    2010-12-01

    A suite of field sites located on or near serpentine associated with a peridotite from Turkey (southern strand of the Northern Anatolian Fault Zone) allow simultaneous evaluation of the geology, mineralogy, aqueous geochemistry, and microbiology. In this work, we present aqueous geochemistry of spring fluids tapping subsurface hydrological regimes impacted to differing extents by serpentinization of regionally important ultramafic blocks and also by ongoing hydrothermal activity and infiltration of meteoric water (see summary table below). We model the feasibility of metabolisms including sulfate reduction, iron oxidation, nitrate reduction, methanogenesis, and methanotrophy based on the geochemistry of spring, seep, and thermal well waters. We predict that microbiology should follow geochemistry in this subsurface environment, and clarify geochemical controls on chemosynthetic metabolisms in serpentinizing systems and systems in which serpentinization co-occurs with other geological processes, in relevant mixing scenarios. The finding that subsurface mafic and ultramafic rock formations can, and apparently do (see companion poster, Meyer-Dombard et al.), host microbial life has direct implications for origin of life debates and astrobiology.

  19. Easy Synthesis and Characterization of Poly(alkoxysilane)s Promoted by Silver-Platinum Mixed Complexes.

    PubMed

    Roh, Sung-Hee; Lee, In-Hwa; Cheong, Hyeonsook; Noh, Ji Eun; Lee, Ki Bok; Woo, Hee-Gweon; Kim, Bo Hye; Jun, Jin; Sohn, Honglae

    2015-01-01

    One-pot Si-Si/Si-O dehydrocoupling of hydrosilanes with alcohols (1:1.5 mole ratio), promoted by a mixture of AgNO3-H2PtCl6 (150/1 mole ratio) readily gave poly(alkoxysilane)s in good yield (62-91%). The addition of small amount of platinum complex to form nanoparticles facilitated the silicon polymer formation when compared to the reaction rate with AgNO3 alone. The primary/secondary hydrosilanes [p-X-C6H4SiH3 (X = H, CH3, OCH3, F), PhCH2SiH3, and (PhSiH2)2] and alcohols [MeOH, EtOH, (i)PrOH, PhOH, and CF3(CF2)2CH2OH] were used for the reaction. The weight average molecular weight and polydispersity of the poly(alkoxysilane)s were in the range of 1,690-7,100 Dalton and 1.44-3.49, respectively. The reaction of phenylsilane with ethanol (1:3 mole ratio) using the Ag-Pt complexes produced triethoxyphenylsilane only, as expected. The reaction of phenylsilane with Ge-132 produced an insoluble cross-linked gel.

  20. Mixed-Valent Dicobalt and Iron-Cobalt Complexes with High-Spin Configurations and Short Metal-Metal Bonds

    SciTech Connect

    Zall, Christopher M.; Clouston, Laura J.; Young, Jr., Victor G.; Ding, Keying; Kim, Hyun Jung; Zherebetskyy, Danylo; Chen, Yu-Sheng; Bill, Eckhard; Gagliardi, Laura; Lu, Connie C.

    2013-09-23

    Cobalt–cobalt and iron–cobalt bonds are investigated in coordination complexes with formally mixed-valent [M2]3+ cores. The trigonal dicobalt tris(diphenylformamidinate) compound, Co2(DPhF)3, which was previously reported by Cotton, Murillo, and co-workers (Inorg. Chim. Acta 1996, 249, 9), is shown to have an energetically isolated, high-spin sextet ground-state by magnetic susceptibility and electron paramagnetic resonance (EPR) spectroscopy. A new tris(amidinato)amine ligand platform is introduced. By tethering three amidinate donors to an apical amine, this platform offers two distinct metal-binding sites. Using the phenyl-substituted variant (abbreviated as LPh), the isolation of a dicobalt homobimetallic and an iron–cobalt heterobimetallic are demonstrated. The new [Co2]3+ and [FeCo]3+ cores have high-spin sextet and septet ground states, respectively. Their solid-state structures reveal short metal–metal bond distances of 2.29 Å for Co–Co and 2.18 Å for Fe–Co; the latter is the shortest distance for an iron–cobalt bond to date. To assign the positions of iron and cobalt atoms as well as to determine if Fe/Co mixing is occurring, X-ray anomalous scattering experiments were performed, spanning the Fe and Co absorption energies. These studies show only a minor amount of metal-site mixing in this complex, and that FeCoLPh is more precisely described as (Fe0.94(1)Co0.06(1))(Co0.95(1)Fe0.05(1))LPh. The iron–cobalt heterobimetallic has been further characterized by Mössbauer spectroscopy. Its isomer shift of 0.65 mm/s and quadrupole splitting of 0.64 mm/s are comparable to the related diiron complex, Fe2(DPhF)3. On the basis of spectroscopic data and theoretical calculations, it is proposed that the formal [M2]3+ cores are fully delocalized.

  1. Characterization of the mixed axial ligand complex (4-cyanopyridine)(imidazole)(tetramesitylporphinato)iron(iii) perchlorate. Stabilization by synergic bonding

    PubMed Central

    Serth-Guzzo, Judith A.; Turowska-Tyrk, Ilona; Safo, Martin K.; Walker, F. Ann; Debrunner, Peter G.; Scheidt, W. Robert

    2016-01-01

    The reaction of [Fe(TMP)(OClO3)], where TMP is the dianion of tetramesitylporphyrin, with a combination of a strong π-acceptor ligand and a π-donating imidazole can lead to the preparation of mixed-ligand complexes [Fe(Porph)(4-CNPy)(L)]+ where L is imidazole itself or 1-acetylimidazole and 4-cyanopyridine is the strong π acceptor ligand. The stability of the new mixed-ligand pair is the presumed result of synergic bonding between the two axial ligands. The molecular structure and other characterization of the new mixed axial ligand complex, [Fe(TMP)(4-CNPy)(HIm)]ClO4 is described. The axial ligands have a relative perpendicular arrangement with Fe–N(imidazole) = 1.945 Å and Fe–N(pyridine) = 2.021 Å The average equatorial Fe–Np distance is 1.963 Å, which is consistent with the S4-ruffled TMP core. Despite the relative perpendicular arrangement of axial ligands, the EPR spectrum of the complex is a rhombic signal and not a large gmax signal. The EPR g-values are g1 = 3.05, g2 = 2.07, and g3 = 1.22. A quadrupole doublet was seen in the Mössbauer spectrum with an isomer shift of 0.197 mm/s and quadrupole splitting of 1.935 mm/s. Two crystalline forms of [Fe(TMP)(4-CNPy)(HIm)]ClO4 have been characterized; the two forms differ only in the solvent content of the lattice. Crystal data for form A: a = 15.432 (12) Å, b = 20.696 (2) Å, c = 19.970 (5) Å, and β = 99.256 (14)°, monoclinic, space group P21/n, V = 6295 (2) Å3, Z = 4, formula FeCl3O4N8C69H69, 8397 observed data, R1 = 0.086, wR2 = 0.210, refinement on F 2. Crystal data for form B: a = 15.267 (3) Å, b = 20.377 (6) Å, c = 19.670 (4) Å, and β = 98.14 (1)°, monoclinic, space group P21/n, V = 6058 (4) Å3, Z = 4, formula C65.25H60.5Cl1.5FeN8O4, 5464 observed data, R1 = 0.096, wR2 = 0.112, refinement on F. PMID:27574390

  2. Ligand redox activity and mixed valency in first-row transition-metal complexes containing tetrachlorocatecholate and radical tetrachlorosemiquinonate ligands.

    PubMed

    Pierpont, Cortlandt G

    2011-10-17

    Ligand noninnocence occurs for complexes composed of redox-active ligands and metals, with frontier orbitals of similar energy. Usually methods of analysis can be used to define the charge distribution, and cases where the metal oxidation state and ligand charge are unclear are unusual. Ligands derived from o-benzoquinones can bond with metals as radical semiquinonates (SQ(•-)) or as catecholates (Cat(2-)). Spectroscopic, magnetic, and structural properties can be used to assess the metal and ligand charges. With the redox activity at both the metal and ligands, reversible multicomponent redox series can be observed using electrochemical methods. Steps in the series may occur at either the ligand or metal, and ligand substituent effects can be used to tune the range of ligand-based redox steps. Complexes that appear as intermediates in a ligand-based redox series may contain both SQ and Cat ligands "bridged" by the metal as mixed-valence complexes. Properties reflect the strength of metal-mediated interligand electronic coupling in the same way that ligand-bridged bimetallics conform to the Robin and Day classification scheme. In this review, we will focus specifically on complexes of first-row transition-metal ions coordinated with three ligands derived from tetrachloro-1,2-benzoquinone (Cl(4)BQ). The redox activity of this ligand overlaps with the potentials of common metal oxidation states, providing examples of metal- and ligand-based redox activity, in some cases, within a single redox series. The strength of the interligand electronic coupling is important in defining the separation between ligand-based couples of a redox series. The complex of ferric iron will be described as an example where coupling is weak, and the steps associated with the Fe(III)(Cl(4)SQ)(3)/[Fe(III)(Cl(4)Cat)(3)](3-) redox series are observed over a narrow range in electrochemical potential.

  3. DNA-interaction and in vitro antimicrobial studies of some mixed-ligand complexes of cobalt(II) with fluoroquinolone antibacterial agent ciprofloxacin and some neutral bidentate ligands.

    PubMed

    Patel, M N; Chhasatia, M R; Gandhi, D S

    2009-05-15

    Six new mixed-ligand complexes of Co(II) with ciprofloxacin (Cip) and neutral bidentate ligands have been synthesized and characterized. Binding and cleavage of DNA with the complex were investigated using spectroscopic method, viscosity measurements and gel electrophoresis techniques. Antibacterial activity has been assayed against two Gram((-ve)) and three Gram((+ve)) microorganisms using the doubling dilution technique.

  4. Synthesis, structure, and single-molecule magnetic properties of rare-earth sandwich complexes with mixed phthalocyanine and Schiff base ligands.

    PubMed

    Wang, Hailong; Cao, Wei; Liu, Tao; Duan, Chunying; Jiang, Jianzhuang

    2013-02-11

    Double- and quadruple-decker complexes of rare-earth metals with mixed phthalocyanine and Schiff base ligands have been synthesized and structurally and magnetically characterized. These complexes (see picture: Dy pink, Ca green, N blue, C black) extend the scope of sandwich-type tetrapyrrole-based rare-earth molecular materials.

  5. Sleep deprivation in parents caring for children with complex needs at home: a mixed methods systematic review.

    PubMed

    McCann, Damhnat; Bull, Rosalind; Winzenberg, Tania

    2015-02-01

    A significant number of children with a range of complex conditions and health care needs are being cared for by parents in the home environment. This mixed methods systematic review aimed to determine the amount of sleep obtained by these parents and the extent to which the child-related overnight health or care needs affected parental sleep experience and daily functioning. Summary statistics were not able to be determined due to the heterogeneity of included studies, but the common themes that emerged are that parents of children with complex needs experience sleep deprivation that can be both relentless and draining and affects the parents themselves and their relationships. The degree of sleep deprivation varies by diagnosis, but a key contributing factor is the need for parents to be vigilant at night. Of particular importance to health care professionals is the inadequate overnight support provided to parents of children with complex needs, potentially placing these parents at risk of poorer health outcomes associated with sleep deprivation and disturbance. This needs to be addressed to enable parents to remain well and continue to provide the care that their child and family require. © The Author(s) 2014.

  6. Two mixed-NH3/amine platinum (II) anticancer complexes featuring a dichloroacetate moiety in the leaving group

    PubMed Central

    Liu, Weiping; Su, Jia; Jiang, Jing; Li, Xingyao; Ye, Qingsong; Zhou, Hongyu; Chen, Jialin; Li, Yan

    2013-01-01

    Two mixed-NH3/amine platinum (II) complexes of 3-dichoroacetoxylcyclobutane-1, 1-dicarboxylate have been prepared in the present study and characterized by elemental analysis and IR, HPLC-MS and 1H, 13C-NMR. The complexes exist in equilibrium between two position isomeric forms and undergo hydrolysis reaction in aqueous solution, releasing the platinum pharmacophores and dichloroacetate which is a small-molecular cell apoptosis inducer. Both complexes were evaluated for in vitro cytotoxic profile in A549, SGC-7901 and SK-OV-3 caner cells as well as in BEAS-2B normal cells. They exhibit markedly cytoxicity toward cancer cells by selectively inducing the apoptosis of cancer cells, whereas leaving normal cells less affected. They have also the ability to overcome the resistance of SK-OV-3 cancer cells to cisplatin. Our findings offer an alternative novel way to develop platinum drugs which can both overcome the drug resistance and selectively target tumor cells. PMID:23955304

  7. Mixed dinitrogen-organocyanamide complexes of molybdenum(0) and their protic conversion into hydrazide and amidoazavinylidene derivatives.

    PubMed

    Cunha, Sónia M P R M; Guedes da Silva, M Fátima C; Pombeiro, Armando J L

    2003-03-24

    Organocyanamides, Ntbd1;CNR(2) (R = Me or Et), react with trans-[Mo(N(2))(2)(dppe)(2)] (1, dppe = Ph(2)PCH(2)CH(2)PPh(2)), in THF, to give the first mixed molybdenum dinitrogen-cyanamide complexes trans-[Mo(N(2))(NCNR(2))(dppe)(2)] (R = Me 2a or Et 2b) which are selectively protonated at N(2) by HBF(4) to yield the hydrazide(2-) complexes trans-[Mo(NNH(2))(NCNR(2))(dppe)(2)][BF(4)](2) (R = Me, 3a, or Et, 3b). On treatment with Ag[BF(4)], oxidation and metal fluorination occur, and the ligating cyanamide undergoes an unprecedented beta-protonation at the unsaturated C atom to form trans-[MoF(NCHNR(2))(dppe)(2)][BF(4)](2) (R = Me, 4a, or Et, 4b) compounds which present the novel amidoazavinylidene (or amidomethyleneamide) ligands. Complexes 4 are also formed from the corresponding compounds 3, with liberation of ammonia and hydrazine. The crystal structure of 2b was determined by single-crystal X-ray diffraction analysis which indicates that the N atom of the amide group has a trigonal planar geometry.

  8. Sequential energy and charge transfer processes in mixed host-guest complexes of subphthalocyanine, porphyrin and phthalocyanine chromophores.

    PubMed

    Menting, Roel; Ng, Dennis K P; Röder, Beate; Ermilov, Eugeny A

    2012-11-14

    Porphyrins, phthalocyanines and subphthalocyanines are three attractive classes of chromophores with intriguing properties making them suitable for the design of artificial photosynthetic systems. The assembly of these components by a supramolecular approach is of particular interest as it provides a facile means to build multi-chromophoric arrays with various architectures and tuneable photophysical properties. In this paper, we show the formation of mixed host-guest supramolecular complexes that consist of a β-cyclodextrin-conjugated subphthalocyanine, a tetrasulfonated porphyrin and a series of silicon(IV) phthalocyanines substituted axially with two β-cyclodextrins via different spacers. We found that the three components form supramolecular complexes held by host-guest interactions in aqueous solution. Upon excitation of the subphthalocyanine part of the complex, the excitation energy is delivered to the phthalocyanine unit via excitation energy transfer and the porphyrin chromophore acts as an energy transfer bridge enabling this process. It was shown that photo-induced charge transfer also takes place. A sequential electron transfer process from the porphyrin unit to the phthalocyanine moiety and subsequently from the subphthalocyanine moiety to the porphyrin unit takes place, and the probability of this process is controlled by the linker between β-cyclodextrin and phthalocyanine. The lifetime of the charge-separated state was found to be 1.7 ns by transient absorption spectroscopy.

  9. Crystal structures of two mixed-valence copper cyanide complexes with N-methyl-ethylenedi-amine.

    PubMed

    Corfield, Peter W R; Sabatino, Alexander

    2017-02-01

    The crystal structures of two mixed-valence copper cyanide compounds involving N-methyl-ethylenedi-amine (meen), are described. In compound (I), poly[bis(μ3-cyanido-κ3C:C:N)tris(μ2-cyanido-κ2C:N)bis(N-methylethane-1,2-di-amine-κ2N,N')tricopper(I)copper(II)], [Cu4(CN)5(C3H10N2)2] or Cu4(CN)5meen2, cyanide groups link Cu(I) atoms into a three-dimensional network containing open channels parallel to the b axis. In the network, two tetra-hedrally bound Cu(I) atoms are bonded by the C atoms of two end-on bridging CN groups to form Cu2(CN)6 moieties with the Cu atoms in close contact at 2.560 (1) Å. Other trigonally bound Cu(I) atoms link these units together to form the network. The Cu(II) atoms, coordinated by two meen units, are covalently linked to the network via a cyanide bridge, and project into the open network channels. In the mol-ecular compound (II), [(N-methylethylenediamine-κ(2)N,N')copper(II)]-μ(2)-cyanido-κ(2)C:N-[bis(cyanido-κC)copper(I)] monohydrate, [Cu2(CN)3(C3H10N2)2]·H2O or Cu2(CN)3meen2·H2O, a CN group connects a Cu(II) atom coordinated by two meen groups with a trigonal-planar Cu(I) atom coordinated by CN groups. The mol-ecules are linked into centrosymmetric dimers via hydrogen bonds to two water mol-ecules. In both compounds, the bridging cyanide between the Cu(II) and Cu(I) atoms has the N atom bonded to Cu(II) and the C atom bonded to Cu(I), and the Cu(II) atoms are in a square-pyramidal coordination.

  10. Horizontal heat fluxes over complex terrain computed using a simple mixed-layer model and a numerical model

    SciTech Connect

    Kimura, Fujio; Kuwagata, Tuneo

    1995-02-01

    The thermally induced local circulation over a periodic valley is simulated by a two-dimensional numerical model that does-not include condensational processes. During the daytime of a clear, calm day, heat is transported from the mountainous region to the valley area by anabatic wind and its return flow. The specific humidity is, however, transported in an inverse manner. The horizontal exchange rate of sensible heat has a horizontal scale similarity, as long as the horizontal scale is less than a critical width of about 100 km. The sensible heat accumulated in an atmospheric column over an arbitrary point can be estimated by a simple model termed the uniform mixed-layer model (UML). The model assumes that the potential temperature is both vertically and horizontally uniform in the mixed layer, even over the complex terrain. The UML model is valid only when the horizontal scale of the topography is less than the critical width and the maximum difference in the elevation of the topography is less than about 1500 m. Latent heat is accumulated over the mountainous region while the atmosphere becomes dry over the valley area. When the horizontal scale is close to the critical width, the largest amount of humidity is accumulated during the late afternoon over the mountainous region. 18 refs., 15 figs., 1 tab.

  11. Mixed (phthalocyaninato)(Schiff-base) di-dysprosium sandwich complexes. Effect of magnetic coupling on the SMM behavior.

    PubMed

    Wang, Hailong; Liu, Chenxi; Liu, Tao; Zeng, Suyuan; Cao, Wei; Ma, Qi; Duan, Chunying; Dou, Jianmin; Jiang, Jianzhuang

    2013-11-21

    Reaction between Schiff-base ligand and half-sandwich complex M(Pc)(acac) led to the isolation of new sandwich-type mixed (phthalocyaninato)(Schiff-base) di-lanthanide compounds M2(Pc)2(L)H2O (M = Dy, Gd) (1, 2) [H2Pc = metal free phthalocyanine, Hacac = acetylacetone, H2L = N,N'-bis(3-methyloxysalicylidene)benzene-1,2-diamine] with the triple-decker molecular structure clearly revealed by single crystal X-ray diffraction analysis. For the comparative studies, sandwich triple-decker analogues with pure Schiff-base ligand M2(L)3H2O (M = Dy, Gd) (3, 4) were also prepared. Dynamic magnetic measurement result reveals the single-molecule magnet (SMM) nature of the di-dysprosium derivative 1, while the static magnetic investigation over both pure and the diamagnetic diluted samples of this compound discloses the interionic ferromagnetic coupling between the two dysprosium ions, which in turn effectively suppresses the QTM and enhances the energy barrier of this SMM. Nevertheless, comparative studies over the static magnetic properties of the di-dysprosium triple-decker complexes 1 and 3 indicate the stronger magnetic coupling between the two lanthanide ions in mixed (phthalocyaninato)(Schiff-base) species than in the pure Schiff-base triple-decker analogue, suggesting the special coordination sphere around the dysprosium ions in the former compound over the latter one on the more intense inter-ionic ferromagnetic coupling. As a very small step towards understanding the structure-property relationship, the present result will be surely helpful for the design and synthesis of the multinuclear lanthanide-based SMMs with good properties.

  12. Consonant and syllable complexity of toddlers with Down syndrome and mixed-aetiology developmental delays

    PubMed Central

    SOKOL, SHARI B.; FEY, MARC E.

    2014-01-01

    This study examines whether speech sound production of toddlers with Down syndrome (DS) is on par with or more severely impaired than that of mental age (MA) peers with developmental delay due to aetiologies other than Down syndrome at two points within an 18-month period near the onset of spoken word production. The utterances of 26 children with DS, aged 24–33 months, with a mean MA of 14.3 months, originally studied by Fey et al. (2006) and Warren et al. (2008) were compared to those of a group of 22 children with similar intellectual and communication delay but no DS (NDS). Phonological measures included the size of the consonant inventory, syllable shape complexity, and number of communication acts with canonical vocalizations. At Time 1, the DS group performed as well as or better than the NDS group on these measures of speech production. At Time 2, 18 months later, the DS group was behind the NDS group on the same measures. Results extended the pattern of more severe impairment in children with DS than NDS peers commonly noted in expressive language to measures of phonological development. PMID:24050845

  13. Exchange Interactions on the Highest-Spin Reported Molecule: the Mixed-Valence Fe42 Complex

    PubMed Central

    Aravena, Daniel; Venegas-Yazigi, Diego; Ruiz, Eliseo

    2016-01-01

    The finding of high-spin molecules that could behave as conventional magnets has been one of the main challenges in Molecular Magnetism. Here, the exchange interactions, present in the highest-spin molecule published in the literature, Fe42, have been analysed using theoretical methods based on Density Functional Theory. The system with a total spin value S = 45 is formed by 42 iron centres containing 18 high-spin FeIII ferromagnetically coupled and 24 diamagnetic low-spin FeII ions. The bridging ligands between the two paramagnetic centres are two cyanide ligands coordinated to the diamagnetic FeII cations. Calculations were performed using either small Fe4 or Fe3 models or the whole Fe42 complex, showing the presence of two different ferromagnetic couplings between the paramagnetic FeIII centres. Finally, Quantum Monte Carlo simulations for the whole system were carried out in order to compare the experimental and simulated magnetic susceptibility curves from the calculated exchange coupling constants with the experimental one. This comparison allows for the evaluation of the accuracy of different exchange-correlation functionals to reproduce such magnetic properties. PMID:27033418

  14. Extended X-ray absorption fine structure data analysis of copper (II) hydroxamic acid mixed ligand complexes

    NASA Astrophysics Data System (ADS)

    Parsai, N.; Mishra, A.; Shrivastava, B. D.

    2014-09-01

    The X-ray absorption spectra of copper mixed ligand complexes, having hydroxamic acid as one of the ligands, have been recorded at the K-edge of copper at BL-8 Dispersive EXAFS beamline at the 2.5 GeV INDUS-2 Synchrotron, RRCAT, Indore, India. For the analysis of EXAFS data, crystallographic data of the complex or of its analog is required, which is not available. Hence, for the analysis of EXAFS data, theoretical EXAFS data of the studied complexes have been generated using the EXAFS equation employing computer software program Mathcad. Firstly, the experimental data has been processed using the computer program Athena to obtain the normalized absorption versus energy data. From the experimental EXAFS data, the phase shift parameter (an energy independent constant 5) has been computed using Lytle, Sayers and Stern's (LSS) method. The backscattering amplitude has been taken from the available theoretical tabulations and other parameters have been taken from crystallographic data of the copper metal. Fourier transforms of both the experimental and theoretical data have been computed, and the two Fourier transforms are found to agree with each other for all the complexes. The position of the first peak in the Fourier transform gives the value of the first shell bond length, which is shorter than the actual bond length as a result of energy dependence of the phase factor (5(k)) in the sine function of the EXAFS equation. Since, the Fourier transform method and LSS method both are uncorrected for phase and other parameters of the EXAFS equation, the present method gives phase uncorrected bond length of the first coordination shell.

  15. Extended X-ray absorption fine structure data analysis of copper (II) hydroxamic acid mixed ligand complexes

    NASA Astrophysics Data System (ADS)

    Parsai, N.; Mishra, A.; Shrivastava, B. D.

    2014-09-01

    The X-ray absorption spectra of copper mixed ligand complexes, having hydroxamic acid as one of the ligands, have been recorded at the K-edge of copper at BL-8 Dispersive EXAFS beamline at the 2.5 GeV INDUS-2 Synchrotron, RRCAT, Indore, India. For the analysis of EXAFS data, crystallographic data of the complex or of its analog is required, which is not available. Hence, for the analysis of EXAFS data, theoretical EXAFS data of the studied complexes have been generated using the EXAFS equation employing computer software program Mathcad. Firstly, the experimental data has been processed using the computer program Athena to obtain the normalized absorption versus energy data. From the experimental EXAFS data, the phase shift parameter (an energy independent constant 5) has been computed using Lytle, Sayers and Stern's (LSS) method. The backscattering amplitude has been taken from the available theoretical tabulations and other parameters have been taken from crystallographic data of the copper metal. Fourier transforms of both the experimental and theoretical data have been computed, and the two Fourier transforms are found to agree with each other for all the complexes. The position of the first peak in the Fourier transform gives the value of the first shell bond length, which is shorter than the actual bond length as a result of energy dependence of the phase factor (δ(k)) in the sine function of the EXAFS equation. Since, the Fourier transform method and LSS method both are uncorrected for phase and other parameters of the EXAFS equation, the present method gives phase uncorrected bond length of the first coordination shell.

  16. Heat- and light-induced detachment of the light harvesting complex from isolated photosystem I supercomplexes.

    PubMed

    Nellaepalli, Sreedhar; Zsiros, Ottó; Tóth, Tünde; Yadavalli, Venkateswarlu; Garab, Győző; Subramanyam, Rajagopal; Kovács, László

    2014-08-01

    In a previous study, using photosystem I enriched stroma thylakoid membrane vesicles, we have shown that the light harvesting complexes of this photosystem are prone to heat- and light-induced, thermo-optically driven detachment from the supercomplex [43]. We have also shown that the splitting of the supercomplex occurs in a gradual and specific manner, selectively affecting the different constituents of the antenna complexes. Here we further analyse these heat- and light-induced processes in isolated Photosystem I supercomplex using circular dichroism and 77K fluorescence emission spectroscopy and immuno blotting, and obtain further details on the sequence of events of the dissociation process as well as on the thermal stability of the different components. Our absorption and circular dichroism spectroscopy and immuno blotting data show that the dissociation of LHCI from PSI-LHCI supercomplex starts above 50°C. Also, the low temperature fluorescence emission spectra depicts decrease of maximum fluorescence emission at 730nm and an increase of the intensity at 685nm, and about 10nm blue-shifts, from 730 to 720nm and from 685 to 676nm, respectively, indicating the heat (50°C) induced detachment of LHCI from PSI core complexes. The reaction centre proteins are highly stable even at high temperatures. Lhca2 is more heat stable than the other light harvesting protein complexes of PSI, whereas Lhca4 and Lhca3 are rather labile. Combined heat and light treatments significantly enhances the disorganization of PSI-LHCI supercomplexes, indicating a thermo-optic mechanism, which might have significant role under combined heat and light stress conditions. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Single-step preparation of the mixed Ba(II)-Nb(V) oxides from a heteropolynuclear oxalate complex.

    PubMed

    Jurić, Marijana; Popović, Jasminka; Šantić, Ana; Molčanov, Krešimir; Brničević, Nevenka; Planinić, Pavica

    2013-02-18

    A novel oxalate-based complex of the formula {Ba(2)(H(2)O)(5)[NbO(C(2)O(4))(3)]HC(2)O(4)}·H(2)O (1) was prepared from an aqueous solution containing the [NbO(C(2)O(4))(3)](3-) and Ba(2+) entities in the molar ratio 1:2, and characterized by X-ray single-crystal diffraction, IR spectroscopy, and thermal analysis. The crystal packing of 1 reveals a complex three-dimensional (3D) network: the Nb polyhedron is connected to eight neighboring Ba polyhedra through the oxalate ligands and the oxo-oxygen group, whereas the Ba polyhedra share edges and vertices. The ability of compound 1 to act as a single-source precursor for the formation of bimetallic oxides was investigated by the thermal analysis (TGA and DSC) and X-ray powder diffraction. Thermal processing of 1 resulted in the formation of mixed-metal oxide phases, Ba(4)Nb(2)O(9) and Ba(5)Nb(4)O(15). Three stable polymorphs of Ba(4)Nb(2)O(9) were isolated: the known, hexagonal α- and orthorhombic γ-Ba(4)Nb(2)O(9), and another one, not previously reported, hexagonal δ-Ba(4)Nb(2)O(9) polymorph. The new, δ-Ba(4)Nb(2)O(9) polymorph has the 6H-perovskite structure (space group P6(3)/m), in which the Nb(2)O(9)(8-) face-sharing octahedral dimers are interconnected via corners to the regular BaO(6)(10-) octahedra. Formation of the mixed-metal oxides takes place at different temperatures: the Ba(5)Nb(4)O(15) oxide occurred at ∼700 °C, as the major crystalline oxide phase; by heating the sample up to 1135 °C, the α-Ba(4)Nb(2)O(9) form was obtained, whereas the heating at 1175 °C caused the crystallization of two polymorphs, γ-Ba(4)Nb(2)O(9) and δ-Ba(4)Nb(2)O(9). Special focus was set on the electrical properties of the prepared mixed Ba(II)-Nb(V) oxides obtained by this molecular pathway in a single-step preparation.

  18. Evidence for Complex Mixing Processes Controlling the Composition of a Wide Range of Alkaline Volcanic Rocks at Minna Bluff, Antarctica.

    NASA Astrophysics Data System (ADS)

    Dunbar, N. W.; Panter, K.; Scanlan, M. K.; Fargo, A.; McIntosh, W. C.; Wilch, T. I.

    2008-12-01

    Minna Bluff, a 45-km-long chain of coalesced volcanic centers formed by a wide range of alkaline magmatic compositions. Compositions between basanite and phonolite are represented and these form volcanic features ranging from small, primitive, cinder cones to large, evolved domes. Abundant stacked lava flows (subaerial to subglacial), feeder dikes, and vent complexes are exposed in cliffs up to ~1000 m in height. A notable field feature of many of the volcanic rocks at Minna Bluff is the presence of large (up to 5 cm) amphibole and feldspar megacrysts, which are found in rocks of a range of compositions and eruptive styles. Microprobe analysis shows that many lavas exhibit strikingly common disequilibrium textures, consisting primarily of phenocrystic kaersutitic to ferro-kaersutitic amphibole that is either partially, or fully, broken down to a combination of plagioclase, pyroxene and magnetite. The extent to which breakdown has occurred varies from crystal to crystal. In some cases, a breakdown rim of only a few 10s of microns thickness is present, whereas in other parts of the sample, mm-scale kaersutites are almost completely reacted. Although individual phenocrysts are compositionally uniform, a range of kaersutite compositions are present (even within a single sample) with FeO and MgO contents between 9.5-18 and 7.5-13.5 wt. percent respectively. Approximately the same compositional range of kaersutite (as well as the same disequilibrium textures) is observed in samples with a range of bulk compositions. Some of the same samples contain feldspar phenocrysts with relatively evolved plagioclase (andesine) cores and more primitive (labradorite) rims. Amphibole-related disequilibrium textures are observed in basanitic lavas containing olivine with Mg- rich cores (Fo87). The textural and compositional characteristics of the Minna Bluff volcanic rocks suggest that, for many, mixing between one or more magmatic sources, shortly before the eruption process, controls

  19. Isovalent Ag(III) /Ag(III) , Ag(II) /Ag(II) , Mixed-Valent Ag(II) /Ag(III) , and Corrolato-Based Mixed-Valency in β,β'-Linked [Bis{corrolato-silver}](n) Complexes.

    PubMed

    Patra, Bratati; Sobottka, Sebastian; Sinha, Woormileela; Sarkar, Biprajit; Kar, Sanjib

    2017-07-28

    Mixed-valent compounds are fascinating entities that are useful as models for investigating electron-transfer reactions, and find use in a host of biologically relevant redox processes. Though the bio-relevant metal copper is well established in mixed-valent chemistry, the Ag(II) /Ag(III) mixed-valent combination of its higher congener in a molecular complex has rarely been reported before. This work reports the synthesis of a new β,β'-linked bis{corrolato-silver(III)} complex and its characterization in five different redox states. A combination of electrochemistry, spectroelectrochemistry, and DFT calculations point to the existence of a mixed-valent Ag(II) /Ag(III) and an isovalent Ag(II) /Ag(II) form. Additionally, characterization of the Ag(III) /Ag(III) form and ligand-based corrolato-centered mixed-valency is presented as well. These results thus open new avenues for bis-corrolato ligands and for mixed-valency in disilver compounds. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Genesis of emulsion texture due to magma mixing: a case study from Chotanagpur Granite Gneiss Complex of Eastern India

    NASA Astrophysics Data System (ADS)

    Gogoi, Bibhuti; Saikia, Ashima; Ahmad, Mansoor

    2016-04-01

    The emulsion texture is a rare magma mixing feature in which rounded bodies of one magmatic phase remain dispersed in the other coherent phase (Freundt and Schmincke, 1992). This type of special texture in hybrid rocks can significantly contribute toward understanding the mechanisms facilitating magma mixing and magma chamber dynamics involving two disparate magmas as the exact processes by which mixing occurs still remain unclear. Recent developments in microfluidics have greatly helped us to understand the complex processes governing magma mixing occurring at micro-level. Presented work uses some of the results obtained from microfluidic experiments with a view to understand the formation mechanism of emulsions preserved in the hybrid rocks of the Ghansura Rhyolite Dome (GRD) of Proterozoic Chotanagpur Granite Gneiss Complex (CGGC), Eastern India. The GRD has preserved hybrid rocks displaying emulsion texture that formed due to the interaction of a phenocryst-rich basaltic magma and host rhyolite magma. The emulsions are more or less spherical in shape and dominantly composed of amphibole having biotite rinds set in a matrix of biotite, plagioclase, K-feldspar and quartz. Amphibole compositions were determined from the core of the emulsions to the rim with a view to check for cationic substitutions. The amphibole constituting the emulsions is actinolite in composition, and commonly shows tschermakite (Ts) and pargasite (Prg) substitutions. From petrographical and mineral-chemical analyses we infer that when mafic magma, containing phenocrysts of augite, came in contact with felsic magma, diffusion of cations like H+, Al3+and others occurred from the felsic to the mafic system. These cations reacted with the clinopyroxene phenocrysts in the mafic magma to form amphibole (actinolite) crystals. The formation of amphibole crystals in the mafic system greatly increased the viscosity of the system allowing the amphibole crystals to venture into the adjacent felsic

  1. Reactivity towards nitriles, cyanamides, and carbodiimides of palladium complexes derived from benzyl alcohol. Synthesis of a mixed Pd2Ag complex.

    PubMed

    Fernández-Rodríguez, María-José; Martínez-Viviente, Eloísa; Vicente, José; Jones, Peter G

    2016-01-14

    The chelate complex [Pd(κ(2)-C,O-C6H4CH2O-2)(bpy)] () reacts with acetonitrile, cyanamides, or carbodiimides, in the presence of AgOTf (1 : 5 : 1 molar ratio) and residual water, to form complexes [Pd{κ(2)-C,N-C6H4{CH2OC([double bond, length as m-dash]NX)Y}-2}(bpy)](OTf), where X = H, Y = Me (), NMe2 (), NEt2 (), X = R, Y = NHR (R = (i)Pr (), Tol ()), as a result of the insertion of the unsaturated reagent into the O-Pd bond of and the protonation of one of the N atoms. In the absence of AgOTf the reaction of with TolN[double bond, length as m-dash]C[double bond, length as m-dash]NTol (Tol = p-Tolyl) results in the formation of the neutral complex [Pd{κ(2)-C,N-C6H4{CH2OC([double bond, length as m-dash]NTol)NTol}-2}(bpy)] (). Complexes and can be interconverted by deprotonation ( + KO(t)Bu) or protonation ( + KOTf + HOTf) reactions. When the reaction of with TolN[double bond, length as m-dash]C[double bond, length as m-dash]NTol in the presence of AgOTf is carried out in a 1 : 1 : 1 stoichiometric ratio, or for a short period of time, a mixture of and a mixed heterometallic Ag2Pd complex is obtained ( = [Ag(N-)2](OTf)). Complex is the major product when the AgOTf is added before the carbodiimide, and the reaction is stopped immediately. can also be obtained by reaction of with 0.5 equiv. of AgOTf. When complex [PdI(C6H4CH2OH-2)(bpy)] () reacts with (i)PrN[double bond, length as m-dash]C[double bond, length as m-dash]N(i)Pr in the presence of TlOTf, instead of AgOTf, a ca. 1 : 1 mixture of and [Pd{κ(2)-O,N-OCH2{C6H4{C([double bond, length as m-dash]NH(i)Pr)N(i)Pr}-2}}(bpy)](OTf) () forms. Complex is the result of the insertion of the carbodiimide into the C-Pd bond. Complexes have been extensively characterized by NMR spectroscopy, and the crystal structures of , , and ·2.5CHCl3·0.5Et2O have been determined by X-ray diffraction studies.

  2. Electrochemical and spectroscopic effects of mixed substituents in bis(phenolate)–copper(II) galactose oxidase model complexes

    PubMed Central

    Pratt, Russell C.; Lyons, Christopher T.; Wasinger, Erik C.; Stack, T. Daniel. P.

    2012-01-01

    Non-symmetric substitution of salen (1R1,R2) and reduced salen (2R1,R2) CuII-phenoxyl complexes with a combination of -tBu, -SiPr, and -OMe substituents leads to dramatic differences in their redox and spectroscopic properties, providing insight into the influence of the cysteine-modified tyrosine cofactor in the enzyme galactose oxidase (GO). Using a modified Marcus-Hush analysis, the oxidized copper complexes are characterized as Class II mixed-valent due to the electronic differentiation between the two substituted phenolates. Sulfur K-edge X-ray absorption spectroscopy (XAS) assesses the degree of radical delocalization onto the single sulfur atom of non-symmetric [1tBu,SMe]+ at 7%, consistent with other spectroscopic and electrochemical results that suggest preferential oxidation of the -SMe bearing phenolate. Estimates of the thermodynamic free-energy difference between the two localized states (ΔG∘) and reorganizational energies (λR1R2) of [1R1,R2]+ and [2R1,R2]+ leads to accurate predictions of the spectroscopically observed IVCT transition energies. Application of the modified Marcus-Hush analysis to GO using parameters determined for [2R1,R2]+ predicts a νmax of ~ 13600 cm−1, well within the energy range of the broad Vis-NIR band displayed by the enzyme. PMID:22471355

  3. Plasmon enhanced molecular absorption: A mixed quantum-classical description of supramolecular complexes attached to a metal nanoparticle

    NASA Astrophysics Data System (ADS)

    Megow, Jörg; May, Volkhard

    2014-01-01

    The application of a mixed quantum-classical methodology for an investigation of single pheophorbide-a molecules (Pheos) and respective supramolecular complexes is continued to effects caused by a nearby placed metal nanoparticle (MNP). Therefore, the classical simulation of the molecular nuclear degrees of freedom is combined with a uniform quantum description of the molecular electronic excitations coupled to those of the MNP. To account for the short MNP plasmon life time the quantum dynamics of the electronic degrees of freedom is formulated in the framework of a system-bath theory. Linear absorption spectra are calculated for a spherical 14 nm diameter Au-MNP decorated with isolated Pheos or with P16 complexes formed by 16 Pheos. The spectra are analyzed with respect to the molecular orientation at the MNP surface. While all studies on P16 only account for the Pheo Qy-transition we also present data on the MNP induced change of the single Pheo Qx-absorption.

  4. Flux balance analysis of mixed microbial cultures: application to the production of polyhydroxyalkanoates from complex mixtures of volatile fatty acids.

    PubMed

    Pardelha, Filipa; Albuquerque, Maria G E; Reis, Maria A M; Dias, João M L; Oliveira, Rui

    2012-12-31

    Fermented agro-industrial wastes are potential low cost substrates for polyhydroxyalkanoates (PHA) production by mixed microbial cultures (MMC). The use of complex substrates has however profound implications in the PHA metabolism. In this paper we investigate PHA accumulation using a lumped metabolic model that describes PHA storage from arbitrary mixtures of volatile fatty acids (VFA). Experiments were conducted using synthetic and complex VFA mixtures obtained from the fermentation of sugar cane molasses. Metabolic flux analysis (MFA) and flux balance analysis (FBA) were performed at different stages of culture enrichment in order to investigate the effect of VFA composition and time of enrichment in PHA storage efficiency. Substrate uptake and PHA storage fluxes increased over enrichment time by 70% and 73%, respectively. MFA calculations show that higher PHA storage fluxes are associated to an increase in the uptake of VFA with even number of carbon atoms and a more effective synthesis of hydroxyvalerate (HV) precursors from VFA with odd number of carbons. Furthermore, FBA shows that the key metabolic objective of a MMC subjected to the feast and famine regimen is the minimization of the tricarboxylic acid cycle fluxes. The PHA flux and biopolymer composition (hydroxybutyrate (HB): HV) could be accurately predicted in several independent experiments. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. The Microgeographical Patterns of Morphological and Molecular Variation of a Mixed Ploidy Population in the Species Complex Actinidia chinensis

    PubMed Central

    Liu, Yifei; Li, Dawei; Yan, Ling; Huang, Hongwen

    2015-01-01

    Polyploidy and hybridization are thought to have significant impacts on both the evolution and diversification of the genus Actinidia, but the structure and patterns of morphology and molecular diversity relating to ploidy variation of wild Actinidia plants remain much less understood. Here, we examine the distribution of morphological variation and ploidy levels along geographic and environmental variables of a large mixed-ploidy population of the A. chinensis species complex. We then characterize the extent of both genetic and epigenetic diversity and differentiation exhibited between individuals of different ploidy levels. Our results showed that while there are three ploidy levels in this population, hexaploids were constituted the majority (70.3%). Individuals with different ploidy levels were microgeographically structured in relation to elevation and extent of niche disturbance. The morphological characters examined revealed clear difference between diploids and hexaploids, however tetraploids exhibited intermediate forms. Both genetic and epigenetic diversity were high but the differentiation among cytotypes was weak, suggesting extensive gene flow and/or shared ancestral variation occurred in this population even across ploidy levels. Epigenetic variation was clearly correlated with changes in altitudes, a trend of continuous genetic variation and gradual increase of epigenomic heterogeneities of individuals was also observed. Our results show that complex interactions between the locally microgeographical environment, ploidy and gene flow impact A. chinensis genetic and epigenetic variation. We posit that an increase in ploidy does not broaden the species habitat range, but rather permits A. chinensis adaptation to specific niches. PMID:25658107

  6. Theoretical investigation of non-covalent interactions and spectroscopic properties of a new mixed-ligand Co(II) complex

    NASA Astrophysics Data System (ADS)

    Chahkandi, Mohammad

    2016-05-01

    A new mixed ligand complex formulated as [Co(pydc)(2-apym)(H2O)2]·H2O (1) (pydcH2 = pyridine-2,6-dicarboxylic acid, 2-apym = 2-aminopyrimidine) has been used for density functional theory (DFT) calculations. The neutral monomeric complex participates in a variety of non-covalent interactions including H-bonding and π-stacking to create a 1-D coordination chain. In order to determine the binding energy of the non-covalent interactions responsible for the crystalline network formation of 1 they have been studied by dispersion corrected density functional theory (DFT-D) calculations. For this purpose, the independent smallest fragment (monomer) and subsequently the related network including seven monomers bearing all non-covalent interactions have been optimized. The results demonstrate that hydrogen bonds, especially N-H···O interactions, govern the network formation. The calculated electronic absorption spectrum agrees with experiment in which three major electron-transition bands derived from (σ, p) → π∗ and π → π∗ ligand to ligand charge transfer (LLCT), and π → n and π → π∗ pydc intra-ligand charge transfer (ILCT) transitions are seen.

  7. Synthesis, characterization and potent superoxide dismutase like activity of novel bis(pyrazole) – 2,2′-bipyridyl mixed ligand copper(II) complexes

    PubMed Central

    Potapov, Andrei S.; Nudnova, Evgenia A.; Domina, Galina A.; Kirpotina, Liliya N.; Quinn, Mark T.; Khlebnikov, Andrei I.; Schepetkin, Igor A.

    2010-01-01

    Eleven new complexes of Cu(II) chloride and nitrate with bis(pyrazol-1-yl)propane and bis[2-(pyrazol-1-yl)ethyl]ether ligands were prepared and characterized by spectral and electrochemical methods. X-ray crystal structure determination of bis[2-(3,5-dimethylpyrazol-1-yl)ethyl]etherdinitratocopper revealed a hepta-coordinated structure with the bis(pyrazole) ligand coordinated in a tridentate NNO-fashion and both of the nitrate ions in a bidentate fashion. Reaction of Cu(II) nitrate complexes with 2,2′-bipyridyl led to the displacement of one of the nitrate ions into the outer sphere and the formation of mixed-ligand complexes. Mixed-ligand bipyridyl Cu(II) complexes demonstrated the highest superoxide dismutase (SOD)-like activity in a chemical superoxide anion-generating system, with IC50 values in the low micromolar range. Density functional theory calculations showed that introduction of a bipypidyl ligand into the complexes dramatically lowered the lowest unoccupied molecular orbital (LUMO) energy level, which explains the increased SOD-like activity of these complexes compared to non-bipy species. These bipy complexes were also effective scavengers of reactive oxygen species generated by phagocytes (human neutrophils and murine bone marrow leukocytes) ex vivo. Thus, these bipy mixed-ligand complexes represent a promising class of SOD mimetics for future development. PMID:19488447

  8. Quinoxaline based bio-active mixed ligand transition metal complexes: Synthesis, characterization, electrochemical, antimicrobial, DNA binding, cleavage, antioxidant and molecular docking studies.

    PubMed

    Dhanaraj, C Justin; Johnson, Jijo

    2015-10-01

    Co(II), Ni(II), Cu(II) and Zn(II) mixed ligand complexes have been synthesized from N(2), N(3)-bis(4-nitrophenyl)quinoxaline-2,3-diamine and 1,10-phenanthroline. The compounds were characterized by elemental analyses, molar conductance, magnetic susceptibility, IR, UV-Vis., (1)H NMR, mass and ESR spectra. Octahedral geometry has been assigned for Co(II), Ni(II) and Zn(II) complexes and distorted octahedral geometry for Cu(II) complex. Electrochemical behavior of the synthesized complexes was studied using cyclic voltammetry. Grain size and surface morphologies of the complexes were determined by powder XRD and SEM analyses. The mixed ligand metal complexes were screened for antimicrobial activity against bacterial species Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus; fungal species Aspergillus niger, and Candida albicans by disc diffusion method. The DNA binding and DNA cleavage activities of the compounds were determined using electronic absorption titration and agarose gel electrophoresis respectively. The superoxide radical scavenging and free radical scavenging activities of the Cu(II) complex was also evaluated. Molecular docking studies of the synthesized mixed ligand metal complexes were carried out against B-DNA dodecamer and the protein Plasmodium falciparum dihydrofolate reductase (pf DHFR).

  9. Hydride reactivity of Ni(II)-X-Ni(II) entities: mixed-valent hydrido complexes and reversible metal reduction.

    PubMed

    Gehring, Henrike; Metzinger, Ramona; Herwig, Christian; Intemann, Julia; Harder, Sjoerd; Limberg, Christian

    2013-01-28

    After the lithiation of PYR-H(2) (PYR(2-) =[{NC(Me)C(H)C(Me)NC(6)H(3)(iPr)(2)}(2)(C(5)H(3)N)](2-)), which is the precursor of an expanded β-diketiminato ligand system with two binding pockets, its reaction with [NiBr(2) (dme)] led to a dinuclear nickel(II)-bromide complex, [(PYR)Ni(μ-Br)NiBr] (1). The bridging bromide ligand could be selectively exchanged for a thiolate ligand to yield [(PYR)Ni(μ-SEt)NiBr] (3). In an attempt to introduce hydride ligands, both compounds were treated with KHBEt(3). This treatment afforded [(PYR)Ni(μ-H)Ni] (2), which is a mixed valent Ni(I)-μ-H-Ni(II) complex, and [(PYR-H)Ni(μ-SEt)Ni] (4), in which two tricoordinated Ni(I) moieties are strongly antiferromagnetically coupled. Compound 4 is the product of an initial salt metathesis, followed by an intramolecular redox process that separates the original hydride ligand into two electrons, which reduce the metal centres, and a proton, which is trapped by one of the binding pockets, thereby converting it into an olefin ligand on one of the Ni(I) centres. The addition of a mild acid to complex 4 leads to the elimination of H(2) and the formation of a Ni(II)Ni(II) compound, [(PYR)Ni(μ-SEt)NiOTf] (5), so that the original Ni(II) (μ-SEt)Ni(II) X core of compound 3 is restored. All of these compounds were fully characterized, including by X-ray diffraction, and their molecular structures, as well as their formation processes, are discussed.

  10. Multi and mixed 3D-printing of graphene-hydroxyapatite hybrid materials for complex tissue engineering.

    PubMed

    Jakus, Adam E; Shah, Ramille N

    2017-01-01

    With the emergence of three-dimensional (3D)-printing (3DP) as a vital tool in tissue engineering and medicine, there is an ever growing need to develop new biomaterials that can be 3D-printed and also emulate the compositional, structural, and functional complexities of human tissues and organs. In this work, we probe the 3D-printable biomaterials spectrum by combining two recently established functional 3D-printable particle-laden biomaterial inks: one that contains hydroxyapatite microspheres (hyperelastic bone, HB) and another that contains graphene nanoflakes (3D-graphene, 3DG). We demonstrate that not only can these distinct, osteogenic, and neurogenic inks be co-3D-printed to create complex, multimaterial constructs, but that composite inks of HB and 3DG can also be synthesized. Specifically, the printability, microstructural, mechanical, electrical, and biological properties of a hybrid material comprised of 1:1 HA:graphene by volume is investigated. The resulting HB-3DG hybrid exhibits mixed characteristics of the two distinct systems, while maintaining 3D-printability, electrical conductivity, and flexibility. In vitro assessment of HB-3DG using mesenchymal stem cells demonstrates the hybrid material supports cell viability and proliferation, as well as significantly upregulates both osteogenic and neurogenic gene expression over 14 days. This work ultimately demonstrates a significant step forward towards being able to 3D-print graded, multicompositional, and multifunctional constructs from hybrid inks for complex composite tissue engineering. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 274-283, 2017.

  11. Investigating vibrational anharmonic couplings in cyanide-bridged transition metal mixed valence complexes using two-dimensional infrared spectroscopy

    SciTech Connect

    Slenkamp, Karla M.; Lynch, Michael S.; Van Kuiken, Benjamin E.; Brookes, Jennifer F.; Bannan, Caitlin C.; Daifuku, Stephanie L.; Khalil, Munira

    2014-02-28

    Using polarization-selective two-dimensional infrared (2D IR) spectroscopy, we measure anharmonic couplings and angles between the transition dipole moments of the four cyanide stretching (ν{sub CN}) vibrations found in [(NH{sub 3}){sub 5}Ru{sup III}NCFe{sup II}(CN){sub 5}]{sup −} (FeRu) dissolved in D{sub 2}O and formamide and [(NC){sub 5}Fe{sup II}CNPt{sup IV}(NH{sub 3}){sub 4}NCFe{sup II}(CN){sub 5}]{sup 4−} (FePtFe) dissolved in D{sub 2}O. These cyanide-bridged transition metal complexes serve as model systems for studying the role of high frequency vibrational modes in ultrafast photoinduced charge transfer reactions. Here, we focus on the spectroscopy of the ν{sub CN} modes in the electronic ground state. The FTIR spectra of the ν{sub CN} modes of the bimetallic and trimetallic systems are strikingly different in terms of frequencies, amplitudes, and lineshapes. The experimental 2D IR spectra of FeRu and FePtFe and their fits reveal a set of weakly coupled anharmonic ν{sub CN} modes. The vibrational mode anharmonicities of the individual ν{sub CN} modes range from 14 to 28 cm{sup −1}. The mixed-mode anharmonicities range from 2 to 14 cm{sup −1}. In general, the bridging ν{sub CN} mode is most weakly coupled to the radial ν{sub CN} mode, which involves the terminal CN ligands. Measurement of the relative transition dipole moments of the four ν{sub CN} modes reveal that the FeRu molecule is almost linear in solution when dissolved in formamide, but it assumes a bent geometry when dissolved in D{sub 2}O. The ν{sub CN} modes are modelled as bilinearly coupled anharmonic oscillators with an average coupling constant of 6 cm{sup −1}. This study elucidates the role of the solvent in modulating the molecular geometry and the anharmonic vibrational couplings between the ν{sub CN} modes in cyanide-bridged transition metal mixed valence complexes.

  12. Dual emission and excited-state mixed-valence in a quasi-symmetric dinuclear Ru-Ru complex.

    PubMed

    Kreitner, Christoph; Grabolle, Markus; Resch-Genger, Ute; Heinze, Katja

    2014-12-15

    The synthesis and characterization of the new dinuclear dipeptide [(EtOOC-tpy)Ru(tpy-NHCO-tpy)Ru(tpy-NHCOCH3)](4+) 3(4+) of the bis(terpyridine)ruthenium amino acid [(HOOC-tpy)Ru(tpy-NH2)](2+) 1(2+) are described, and the properties of the dipeptide are compared to those of the mononuclear complex [(EtOOC-tpy)Ru(tpy-NHCOCH3)](2+) 4(2+) carrying the same functional groups. 3(4+) is designed to serve a high electronic similarity of the two ruthenium sites despite the intrinsic asymmetry arising from the amide bridge. This is confirmed via UV-vis absorption and NMR spectroscopy as well as cyclic voltammetry. 4(2+) and 3(4+) are emissive at room temperature, as expected. Moreover, 3(4+) exhibits dual emission from two different triplet states with different energies and lifetimes at room temperature. This is ascribed to the presence of a unique thermal equilibrium between coexisting [Ru(II)(tpy-NHCO-tpy(·-))Ru(III)] and [Ru(III)(tpy-NHCO-tpy(·-))Ru(II)] states leading to an unprecedented excited-state Ru(II)Ru(III) mixed-valent system via the radical anion bridge tpy-NHCO-tpy(·-). The mixed-valent cation 3(5+), on the other hand, shows no measurable interaction of the Ru(II)Ru(III) centers via the neutral bridge tpy-NHCO-tpy (Robin-Day class I). Reduction of 3(4+) to the radical cation 3(3+) by decamethylcobaltocene is bridge-centered as evidenced by rapid-freeze electron paramagnetic resonance spectroscopy. Interestingly, all attempts to observe 3(3+) via NMR and UV-vis absorption spectroscopy only led to the detection of the diamagnetic complex 3-H(3+) in which the bridging amide is deprotonated. Hence 3-H(3+) (and 4-H(+)) appear to reduce protons to dihydrogen. The ease of single and double deprotonation of 4(2+) and 3(4+) to 4-H(+), 3-H(3+), and 3-2H(2+) was demonstrated using a strong base and was studied using NMR and UV-vis absorption spectroscopies. The equilibrating excited triplet states of 3(4+) are reductively quenched by N,N-dimethylaniline assisted by

  13. Design, synthesis, characterisation and chemical reactivity of mixed-ligand platinum(II) oxadiazoline complexes with potential cytotoxic properties.

    PubMed

    Wagner, Gabriele; Marchant, Anthony; Sayer, James

    2010-09-07

    A series of mixed ligand platinum(II) oxadiazoline complexes bearing 7-nitro-1,3,5-triazaadamantane (7-NO(2)TAA) as a labile and reactive nitrogen ligand has been synthesised from easily accessible starting materials. [2+3] cycloaddition of nitrones R(1)R(2)C-N(+)(Me)O(-) to only one of the nitrile ligands in trans-[PtX(2)(PhCN)(2)] (X = Cl, Br) results in the selective formation of mono-oxadiazoline complexes trans-[PtX(2)(PhCN){N=C(Ph)-O-N(Me)-CR(1)R(2)}] from which the remaining nitrile can be replaced by 7-NO(2)TAA. The resulting complexes trans-[PtX(2)(7-NO(2)TAA) {N=C(Ph)-O-N(Me)-CR(1)R(2)}] and their precursors were characterised by elemental analysis, IR and multinuclear NMR spectroscopy.The suitability of the target complexes as anticancer agents was extrapolated from their general chemical reactivity. They are stable in DMSO, but react with thiols and undergo aquation of a chloro ligand. In the absence of a competing ligand, the coordinated 7-NO(2)TAA ligand slowly hydrolyses in an aqueous medium under release of formaldehyde, and this could induce bioactivity independent of the one typically found with platinum compounds. With nitrogen heterocycles such as pyridine a slow exchange of the 7-NO(2)TAA ligand occurs. A combined DFT/AIM study confirms the reaction observed in the experiment and predicts that other nitrogen heterocycles such as DNA nucleobases should react in the same way. Moreover, the 7-NO(2)TAA should be even more labile in an aqueous medium where protonation of the remaining amines can occur. A PM6 molecular modelling study suggests that the PtCl(oxadiazoline) fragment formed after release of one chloro and the labile 7-NO(2)TAA ligand fits well into the DNA groove and is able to form d(GpG) intrastrand crosslinks similar to the ones observed with cisplatin.

  14. New route to the mixed valence semiquinone-catecholate based mononuclear FeIII and catecholate based dinuclear MnIII complexes: first experimental evidence of valence tautomerism in an iron complex.

    PubMed

    Shaikh, Nizamuddin; Goswami, Sanchita; Panja, Anangamohan; Wang, Xin-Yi; Gao, Song; Butcher, Ray J; Banerjee, Pradyot

    2004-09-20

    The semiquinone-catecholate based mixed valence complex, [FeIII(bispicen)(Cl4Cat)(Cl4SQ)] x DMF (1), and catecholate based (H2bispictn)[Mn2III(Cl4Cat)4(DMF)2] (2) (bispicen = N,N'-bis(2-pyridylmethyl)-1,2-ethanediamine, bispictn = N,N'-bis(2-pyridylmethyl)-1,3-propanediamine, Cl4Cat = tetrachlorocatecholate dianion, and Cl4SQ = tetrachlorosemiquinone radical anion) were synthesized directly utilizing a facile route. Both the complexes have been characterized by single crystal X-ray diffraction study. The electronic structures have been elucidated by UV-vis-NIR absorption spectroscopy, cyclic voltammetry, EPR, and magnetic properties. The structural as well as spectroscopic features support the mixed valence tetrachlorosemiquinone-tetrachlorocatecholate charge distribution in 1. The ligand based mixed valence state was further confirmed by the presence of an intervalence charge transfer (IVCT) band in the 1900 nm region both in solution and in the solid. The intramolecular electron transfer, a phenomenon known as valence tautomerism (VT), has been followed by electronic absorption spectroscopy. For 1, the isomeric form [FeIII(bispicen)(Cl4Cat)(Cl4SQ)] is favored at low temperature, while at an elevated temperature, the [FeII(bispicen)(Cl4SQ)2] redox isomer dominates. Infrared as well as UV-vis-NIR spectral characterization for 2 suggest that the MnIII(Cat)2- moiety is admixed with its mixed valence semiquinone-catecholate isomer MnII(SQ)(Cat)-, and the electronic absorption spectrum is dominated by the mixed charged species. The origin of the intervalence charge transfer band in the 1900 nm range is associated with the mixed valence form, MnII(Cl4Cat)(Cl4SQ)-. The observation of VT in complex 1 is the first example where a mixed valence semiquinone-catecholate iron(III) complex undergoes intramolecular electron transfer similar to manganese and cobalt complexes.

  15. Study of complexation process between 4'-nitrobenzo-15-crown-5 and yttrium(III) cation in binary mixed non-aqueous solvents using conductometric method

    NASA Astrophysics Data System (ADS)

    Habibi, N.; Rounaghi, G. H.; Mohajeri, M.

    2012-12-01

    The complexation reaction of macrocyclic ligand (4'-nitrobenzo-15C5) with Y3+ cation was studied in acetonitrile-methanol (AN-MeOH), acetonitrile-ethanol (AN-EtOH), acetonitrile-dimethylformamide (AN-DMF) and ethylacetate-methanol (EtOAc-MeOH) binary mixtures at different temperatures using conductometry method. The conductivity data show that in all solvent systems, the stoichiometry of the complex formed between 4'-nitrobenzo-15C5 and Y3+ cation is 1: 1 (ML). The stability order of (4'-nitrobenzo-15C5). Y3+ complex in pure non-aqueous solvents at 25°C was found to be: EtOAc > EtOH > AN ≈ DMF > MeOH, and in the case of most compositions of the binary mixed solvents at 25°C it was: AN≈MeOH ≈ AN-EtOH > AN-DMF > EtOAc-MeOH. But the results indicate that the sequence of the stability of the complex in the binary mixed solutions changes with temperature. A non-linear behavior was observed for changes of log K f of (4'-nitrobenzo-15C5 · Y3+) complex versus the composition of the binary mixed solvents, which was explained in terms of solvent-solvent interactions and also the hetero-selective solvation of the species involved in the complexation reaction. The values of thermodynamic parameters (Δ H {c/ℴ} and Δ S {c/ℴ}) for formation of the complex were obtained from temperature dependent of the stability constant using the van't Hoff plots. The results represent that in most cases, the complex is both enthalpy and entropy stabilized and the values and also the sign of thermodynamic parameters are influenced by the nature and composition of the mixed solvents.

  16. Effect of acidity on the equilibria of formation of mixed Co2+ complexes with heparin and arginine in aqueous solutions at 37°C

    NASA Astrophysics Data System (ADS)

    Feofanova, M. A.; Frantseva, Yu. V.; Semenov, A. N.; Baranova, N. V.; Zhuravlev, E. V.

    2014-02-01

    Results from studying interactions in the heparin-Co2+ ion-arginine system are presented. The constants of formation of mixed Co2+ complexes with heparin and arginine in aqueous solutions in a broad pH range at 37°C are determined potentiometrically. The chemical equilibria in the system are simulated and the stoichiometry of formation of the complex forms is determined.

  17. Manganese L-edge X-ray absorption spectroscopy of manganese catalase from Lactobacillus plantarum and mixed valence manganese complexes

    SciTech Connect

    Grush, M.M.; Chen, J.; George, S.J.

    1996-01-10

    The first Mn L-edge absorption spectra of a Mn metalloprotein are presented in this paper. Both reduced and superoxidized Mn catalase have been examined by fluorescence-detected soft X-ray absorption spectroscopy, and their Mn L-edge spectra are dramatically different. The spectrum of reduced Mn(II)Mn(II) catalase has been interpreted by ligand field atomic multiplet calculations and by comparison to model compound spectra. The analysis finds a 10 Dq value of nearly 1.1 eV, consistent with coordination by predominately nitrogen and oxygen donor ligands. For interpretation of mixed valence Mn spectra, an empirical simulation procedure based on the addition of homovalent model compound spectra has been developed and was tested on a variety of Mn complexes and superoxidized Mn catalase. This routine was also used to determine the oxidation state composition of the Mn in [Ba{sub 8}Na{sub 2}ClMn{sub 16}(OH){sub 8}(CO{sub 3}){sub 4}L{sub 8}] .53 H{sub 2}O (L=1,3-diamino-2-hydroxypropane-N,N,N`N`-tetraacetic acid). 27 refs., 6 figs.

  18. Magma mixing in late-stage granitoids of the Pioneer intrusive complex, south central Idaho and tectonic implications

    SciTech Connect

    Woods, A.J.; Geist, D. . Dept. of Geology)

    1993-04-01

    Eocene granitoids that intrude the Pioneer Mountain core complex, located approximately twenty miles northeast of Sun Valley, Idaho, grad west to east from mafic granodiorite to porphyritic quartz monzonite. The two main phases, porphyritic coarse-grained quartz monzonite and fine-grained granodiorite, exhibit field evidence suggestive of magma mixing as indicated by gradational contacts with swirling textures on scales from centimeters to tens of meters, and both phases are found as inclusion within each other. Generally, granodiorite intrudes quartz monzonite and may represent a late stage injection into the center of the semi-consolidated monzonitic magma. Petrological modeling indicates the hybrids are mixtures of the monzonite and granodiorite. Field and petrographic evidence suggest emplacement of the granitoids occurred before latest faulting, as demonstrated by a lack of contact metamorphic effects on the surrounding Paleozoic sediments. Moreover, the development of gneissic fabric, cataclastic and mylonitic fabrics, development of cross-cutting chlorite, epidote, and quartz veinlets, and brecciated fault contacts within the granitoids provide further support for Eocene emplacement prior to or contemporaneous with faulting. These observations provide additional constraints on the cessation of extensional tectonics in south central Idaho.

  19. The complex nature of mixed farming systems requires multidimensional actions supported by integrative research and development efforts.

    PubMed

    González-García, E; Gourdine, J L; Alexandre, G; Archimède, H; Vaarst, M

    2012-05-01

    Mixed farming systems (MFS) have demonstrated some success by focusing on the use of integrative and holistic mechanisms, and rationally building on and using the natural and local resource base without exhausting it, while enhancing biodiversity, optimizing complementarities between crops and animal systems and finally increasing opportunities in rural livelihoods. Focusing our analysis and discussion on field experiences and empirical knowledge in the Caribbean islands, this paper discusses the opportunities for a change needed in current MFS research-development philosophy. The importance of shifting from fragile/specialized production systems to MFS under current global conditions is argued with an emphasis on the case of Small Islands Developing States (SIDS) and the Caribbean. Particular vulnerable characteristics as well as the potential and constraints of SIDS and their agricultural sectors are described, while revealing the opportunities for the 'richness' of the natural and local resources to support authentic and less dependent production system strategies. Examples are provided of the use of natural grasses, legumes, crop residues and agro-industrial by-products. We analyse the requirement for a change in research strategies and initiatives through the development of a complex but necessary multi-/inter-/trans-disciplinary teamwork spirit. We stress as essential the collaboration and active participation of local and regional actors, stakeholders and end-users in the identification of research priorities, as well as the generation, exchange and dissemination of knowledge and technology innovations, while strengthening the leadership roles in the conduct of integrative and participative research and development projects.

  20. Magnetic anisotropy of copper(II) complxes from ESR studies in solution. Use of mixed ligand complexes

    NASA Astrophysics Data System (ADS)

    Das, Ranjan; Prabhananda, B. S.

    ESR linewidhts of the complex Cu(Q) 2 and that of the mixed ligand complx Cu(P)(Q) in liquid solution, where P and Q are two different ligand groups, can be used to determine or confirm the anisotropy of Cu(Q) 2, when the anisotropy parameters associated with Cu(P) 2 are known. This method makes use of (i) the equations derived by Kivelson and coworkers (Wilson and Kivelson, J. Chem. Phys., 44, 154 (1966) ; Atkins and Kivelson, J. Che. Phys., 44, 169 (1966)) ; (ii) equations which find justification in the model proposed by Kuska and coworkers (Kuska, Rogers, and Drullinger, J. Phys. Chem., 71, 109 (1967) ; Kuska, J. Am. Chem. Soc., 97, 2289 (1975)) to explain the variation of metal hyperfine constant. Our proecedure is shown to be promising by taking the example of Cu {i-C 3H 7O) 2PSe 2} 2. This method could be useful when it is difficult to obtain good frozen solution/single crystal ESR spectra.

  1. Child abuse and neglect in complex dissociative disorder, abuse-related chronic PTSD, and mixed psychiatric samples.

    PubMed

    Dorahy, Martin J; Middleton, Warwick; Seager, Lenaire; Williams, Mary; Chambers, Ron

    2016-01-01

    Only a select number of studies have examined different forms of child maltreatment in complex dissociative disorders (DDs) in comparison to other groups. Few of these have used child abuse-related chronic posttraumatic stress disorder (C-PTSD) and mixed psychiatric (MP) patients with maltreatment as comparison groups. This study examined child sexual, physical, and emotional abuse as well as physical and emotional neglect in DD (n = 39), C-PTSD (n = 13), and MP (n = 21) samples, all with abuse and neglect histories. The predictive capacity of these different forms of maltreatment across the 3 groups was assessed for pathological dissociation, shame, guilt, relationship esteem, relationship anxiety, relationship depression, and fear of relationships. All forms of maltreatment differentiated the DD from the MP group, and sexual abuse differentiated the DD sample from the C-PTSD group. Childhood sexual abuse was the only predictor of pathological dissociation. Emotional abuse predicted shame, guilt, relationship anxiety, and fear of relationships. Emotional neglect predicted relationship anxiety and relationship depression. Physical neglect was associated with less relationship anxiety. Different forms of abuse and neglect are associated with different symptom clusters in psychiatric patients with maltreatment histories.

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

    PubMed

    Adeloye, Adewale O

    2011-09-30

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

  3. Carbene-anchored/pendent-imidazolium species as precursors to di-N-heterocyclic carbene-bridged mixed-metal complexes.

    PubMed

    Zamora, Matthew T; Ferguson, Michael J; McDonald, Robert; Cowie, Martin

    2009-09-21

    Reaction of a series of linked diimidazolium dibromide salts with one-half equivalent of [Rh(mu-OAc)(COD)](2) under reflux conditions generates a series of carbene-anchored/pendent-imidazolium complexes, [RhBr(COD)((R)C(H)-eta(1)-C(eth))][Br] ((Me)C(H)-eta(1)-C(eth) = ethylene[(N-methyl)imidazolium][(N-methyl)imidazole-2-ylidene] and (tBu)C(H)-eta(1)-C(eth) = ethylene[(N-tert-butyl)imidazolium][(N-tert-butyl)imidazole-2-ylidene]) via deprotonation of one end of the diimidazolium salt and coordination of the resulting carbene to Rh. Reaction of these complexes with carbon monoxide or the appropriate diphosphine yields either [RhBr(CO)(2)((R)C(H)-eta(1)-C(eth))][Br] (R = Me, (t)Bu) or [RhBr(P( intersection)P)((Me)C(H)-eta(1)-C(eth))][Br] (P( intersection)P = Ph(2)PCH(2)PPh(2), Ph(2)PCH(2)CH(2)PPh(2), Et(2)PCH(2)PEt(2)), respectively. The resulting diphosphine complexes readily decompose in solution. A series of palladium complexes [PdI(3-n)(PR(3))(n)(L)][I](n) (n = 1,2) and [PdI(P( intersection)P)(L)][I](2) (L = (tBu)C(H)-eta(1)-C(meth), (tBu)C(H)-eta(1)-C(eth); (tBu)C(H)-eta(1)-C(meth) = methylene[(N-tert-butyl)imidazolium][(N-tert-butyl)imidazole-2-ylidene]), containing the linked NHC-imidazolium moiety, have also been prepared by reacting the triiodo complexes, [PdI(3)((tBu)C(H)-eta(1)-C(meth))] and [PdI(3)((tBu)C(H)-eta(1)-C(eth))] with several mono- and diphosphines. Attempts to generate mixed Rh/Pd complexes using Pd(OAc)(2) to deprotonate the pendent arm of several of the above carbene-anchored/pendent-imidazolium complexes of Rh have proven unsuccessful. However, a targeted di-NHC-bridged heterobimetallic complex [PdI(2)(PEt(3))(mu-(tBu)CC(meth))RhI(COD)] ((tBu) CC(meth) = 1,1'-methylene-3,3'-di-tert-butyldiimidazol-2,2'-diylidene) can be generated by deprotonation of the imidazolium group in [PdI(2)(PEt(3))((tBu)C(H)-eta(1)-C(meth))][I] using half an equivalent of [Rh(mu-OAc)(COD)](2). The X-ray structure determination of this Pd/Rh complex confirms the

  4. Studies on Mixed Monolayers and Langmuir-Blodgett Films of Schiff-Base Complex Cu(SBC(18))(2) and Calix

    PubMed

    Pang, Shufeng; Ye, Zhifeng; Li, Chun; Liang, Yingqiu

    2001-08-15

    Mixed monolayers of Schiff-base complex Cu(SBC(18))(2) with an octadecyl hydrocarbon chain and Calix[4]arene without a long alkyl chain at an air/water interface were studied in ultrapure water at different temperatures. Interface behavior and thermodynamic estimation of the mixed monolayer indicate that a strong intermolecular interaction exists between the mixed components (Cu(SBC(18))(2) and calix[4]arene) and the two-dimensional miscibility decreases with the molar fraction of Cu(SBC(18))(2). It is noticeable that the calix[4]arene monolayer can be transferred successfully onto solid substrates due to the introduction of Cu(SBC(18))(2). FTIR transmission and UV-Vis absorption spectra of mixed LB films provide further evidence of molecular interaction between the headgroups. Copyright 2001 Academic Press.

  5. Trinuclear nickel complexes with triplesalen ligands: simultaneous occurrence of mixed valence and valence tautomerism in the oxidized species.

    PubMed

    Glaser, Thorsten; Heidemeier, Maik; Fröhlich, Roland; Hildebrandt, Peter; Bothe, Eberhart; Bill, Eckhard

    2005-07-25

    The coordination chemistries of the triple tetradentate triplesalen ligands H(6)talen, H(6)talen(t)(-)(Bu)(2), and H(6)talen(NO)(2) have been investigated with nickel(II). These triplesalen ligands provide three salen-like coordination environments bridged in a meta-phenylene arrangement by a phloroglucinol backbone. The structures of the complexes [(talen)Ni(II)(3)], [(talen(t)(-)(Bu)(2)Ni(II)(3)], and [(talen(NO)(2)Ni(II)(3)] have been determined by single-crystal X-ray diffraction. All three compounds are composed of neutral trinuclear complexes with square-planar coordinated Ni(II) ions in a salen-like coordination environment. Whereas the overall molecular structure of [(talen(NO)(2)Ni(II)(3)] is nearly planar, the structures of [(talen)Ni(II)(3)] and [(talen(t)(-)(Bu)(2)Ni(II)(3)] are bowl-shaped as a result of ligand folding. The strongest ligand folding occurs at the central nickel-phenolate bond of [(talen(t)(-)(Bu)(2)Ni(II)(3)], resulting in the formation of a chiral hemispherical pocket. The dependence of the physical properties by the substituents on the terminal phenolates has been studied by FTIR, resonance Raman, UV-vis-NIR absorption, and electrochemistry. The three nickel-salen subunits are electronically interacting via the pi system of the bridging phloroglucinol backbone. The strength of this interaction is mediated by two opposing effects: the electron density at the terminal phenolates and the folding of the ligand at the central phenolates. The parent complex [(talen)Ni(II)(3)] is irreversibly oxidized at 0.32 V versus ferrocenium/ferrocene (Fc(+)/Fc), whereas [(talen(t)(-)(Bu)2)Ni(II)(3)] and [(talen(NO)(2)Ni(II)(3)] exhibit reversible oxidations at 0.22 V versus Fc(+)/Fc and 0.52 V versus Fc(+)/Fc, respectively. The oxidized species [(talen(t)(-)(Bu)(2)Ni(3)](+) and [(talen(NO)(2)Ni(3)](+) undergo a valence-tautomeric transformation involving a Ni(III) and a phenoxyl radical species, as observed by EPR spectroscopy. Thus, these oxidized

  6. Mixed ligand complexation of some transition metal ions in solution and solid state: Spectral characterization, antimicrobial, antioxidant, DNA cleavage activities and molecular modeling

    NASA Astrophysics Data System (ADS)

    Shobana, Sutha; Dharmaraja, Jeyaprakash; Selvaraj, Shanmugaperumal

    2013-04-01

    Equilibrium studies of Ni(II), Cu(II) and Zn(II) mixed ligand complexes involving a primary ligand 5-fluorouracil (5-FU; A) and imidazoles viz., imidazole (him), benzimidazole (bim), histamine (hist) and L-histidine (his) as co-ligands(B) were carried out pH-metrically in aqueous medium at 310 ± 0.1 K with I = 0.15 M (NaClO4). In solution state, the stoichiometry of MABH, MAB and MAB2 species have been detected. The primary ligand(A) binds the central M(II) ions in a monodentate manner whereas him, bim, hist and his co-ligands(B) bind in mono, mono, bi and tridentate modes respectively. The calculated Δ log K, log X and log X' values indicate higher stability of the mixed ligand complexes in comparison to binary species. Stability of the mixed ligand complex equilibria follows the Irving-Williams order of stability. In vitro biological evaluations of the free ligand(A) and their metal complexes by well diffusion technique show moderate activities against common bacterial and fungal strains. Oxidative cleavage interaction of ligand(A) and their copper complexes with CT DNA is also studied by gel electrophoresis method in the presence of oxidant. In vitro antioxidant evaluations of the primary ligand(A), CuA and CuAB complexes by DPPH free radical scavenging model were carried out. In solid, the MAB type of M(II)sbnd 5-FU(A)sbnd his(B) complexes were isolated and characterized by various physico-chemical and spectral techniques. Both the magnetic susceptibility and electronic spectral analysis suggest distorted octahedral geometry. Thermal studies on the synthesized mixed ligand complexes show loss of coordinated water molecule in the first step followed by decomposition of the organic residues subsequently. XRD and SEM analysis suggest that the microcrystalline nature and homogeneous morphology of MAB complexes. Further, the 3D molecular modeling and analysis for the mixed ligand MAB complexes have also been carried out.

  7. Mixed-metal chloro sulfido cluster complex of molybdenum and platinum, (Mo sub 3 Pt sub 2 S sub 4 Cl sub 4 (PEt sub 3 ) sub 6 )

    SciTech Connect

    Saito, Taro; Tsuboi, Toshio; Kajitani, Yoshimichi; Yamagata, Tsuneaki; Imoto, Hideo )

    1991-09-04

    In the authors recent publication, syntheses of mixed-metal chloro sulfido and chloro selenido complexes of molybdenum and nickel were reported. They were prepared by the reaction of (Mo{sub 3}X{sub 4}Cl{sub 4}(PEt{sub 3}){sub 3}(MeOH){sub 2}) (X = S, Se){sup 2} with Ni(cod){sub 2} (cod = 1,5-cyclooctadiene). In the present study, another excellent building block compound, Pt(cot){sub 2}, was reacted with the same trinuclear molybdenum complex, and the mixed-metal cluster complex (Mo{sub 3}Pt{sub 2}S{sub 4}Cl{sub 4}(PEt{sub 3}){sub 6}) (1) with an unexpected structure was obtained.

  8. Unstable flow, magma mixing and magma-rock deformation in a deep-seated conduit: the Gil-Márquez Complex, south-west Spain

    NASA Astrophysics Data System (ADS)

    Castro, A.; la Rosa, J. D. De; Fernández, C.; Moreno-Ventas, I.

    The Gil-Márquez Complex is an exceptional outcrop of plutonic rocks ranging in composition from diorites to granites emplaced into Devonian terrigenous metasediments of the southernmost part of the Hercynian basement of Iberia. A combined study of this complex, including field geology, petrology, structural geology and geochemistry, reveals that it represents an ancient conduit of magma transport through the continental crust. This conduit allowed the intrusion of magmas of contrasted compositions. Two end-members and several hybrids are identified. The first end-member is a biotite granite and the second is a basaltic magma generated by partial melting of a depleted-mantle source. Both magmas rose through a common channel in which favorable conditions for unstable flow and magma mixing occurred. The observed relations in the Gil-Márquez Complex show that mixing in conduits may be an important mechanism for producing homogeneous hybrid magmas.

  9. Unstable flow, magma mixing and magma-rock deformation in a deep-seated conduit: the Gil-Márquez Complex, south-west Spain

    NASA Astrophysics Data System (ADS)

    Castro, A.; de La Rosa, J. D.; Fernández, C.; Moreno-Ventas, I.

    1995-06-01

    The Gil-Marquez Complex is an exceptional outcrop of plutonic rocks ranging in composition from diorites to granites emplaced into Devonian terrigenous metasediments of the southernmost part of the Hercynian basement of Iberia. A combined study of this complex, including field geology, petrology, structural geology and geochemistry, reveals that it represents an ancient conduit of magma transport through the continental crust. This conduit allowed the intrusion of magmas of contrasted compositions. Two end-members and several hybrids are identified. The first end-member is a biotite granite and the second is a basaltic magma generated by partial melting of a depletedmantle source. Both magmas rose through a common channel in which favorable conditions for unstable flow and magma mixing occurred. The observed relations in the Gil-Márquez Complex show that mixing in conduits may be an important mechanism for producing homogeneous hybrid magmas.

  10. Developing a case mix classification for child and adolescent mental health services: the influence of presenting problems, complexity factors and service providers on number of appointments.

    PubMed

    Martin, Peter; Davies, Roger; Macdougall, Amy; Ritchie, Benjamin; Vostanis, Panos; Whale, Andy; Wolpert, Miranda

    2017-09-01

    Case-mix classification is a focus of international attention in considering how best to manage and fund services, by providing a basis for fairer comparison of resource utilization. Yet there is little evidence of the best ways to establish case mix for child and adolescent mental health services (CAMHS). To develop a case mix classification for CAMHS that is clinically meaningful and predictive of number of appointments attended and to investigate the influence of presenting problems, context and complexity factors and provider variation. We analysed 4573 completed episodes of outpatient care from 11 English CAMHS. Cluster analysis, regression trees and a conceptual classification based on clinical best practice guidelines were compared regarding their ability to predict number of appointments, using mixed effects negative binomial regression. The conceptual classification is clinically meaningful and did as well as data-driven classifications in accounting for number of appointments. There was little evidence for effects of complexity or context factors, with the possible exception of school attendance problems. Substantial variation in resource provision between providers was not explained well by case mix. The conceptually-derived classification merits further testing and development in the context of collaborative decision making.

  11. Spectroscopic, cyclic voltammetric and biological studies of transition metal complexes with mixed nitrogen-sulphur (NS) donor macrocyclic ligand derived from thiosemicarbazide

    NASA Astrophysics Data System (ADS)

    Chandra, Sulekh; Gupta, Lokesh Kumar; Sangeetika

    2005-11-01

    The complexation of new mixed thia-aza-oxa macrocycle viz., 2,12-dithio-5,9,14,18-tetraoxo-7,16-dithia-1,3,4,10,11,13-hexaazacyclooctadecane containing thiosemicarba-zone unit with a series of transition metals Co(II), Ni(II) and Cu(II) has been investigated, by different spectroscopic techniques. The structural features of the ligand have been studied by EI-mass, 1H NMR and IR spectral techniques. Elemental analyses, magnetic moment susceptibility, molar conductance, IR, electronic, and EPR spectral studies characterized the complexes. Electronic absorption and IR spectra of the complexes indicate octahedral geometry for chloro, nitrato, thiocyanato or acetato complexes. The dimeric and neutral nature of the sulphato complexes are confirmed from magnetic susceptibility and low conductance values. Electronic spectra suggests square-planar geometry for all sulphato complexes. The redox behaviour was studied by cyclic voltammetry, show metal-centered reduction processes for all complexes. The complexes of copper show both oxidation and reduction process. The redox potentials depend on the conformation of central atom in the macrocyclic complexes. Newly synthesized macrocyclic ligand and its transition metal complexes show markedly growth inhibitory activity against pathogenic bacterias and plant pathogenic fungi under study. Most of the complexes have higher activity than that of the metal free ligand.

  12. Novel low temperature preparation methods for mixed complex oxide catalysts and their characterisation using in situ SR techniques

    NASA Astrophysics Data System (ADS)

    Beale, Andrew Michael

    The crystallisation of complex mixed oxide and metal phosphate oxidation catalysts prepared using a number of synthetic methods have been studied using in situ synchrotron radiation techniques. Some of these synthesis procedures have previously been employed to produce catalysts whilst others were new methods, making use of hydrothermal technology and zeolite precursors. For the iron phosphates catalysts studied it was observed that all of the synthetic methods employed produced a catalyst precursor having the chemical composition FePO4.2H2O. During calcination this phase transformed into the tridymite and quartz forms of FePO4 although, the material produced by hydrothermal methods was found to be the most phase pure and possess a higher surface area. A comparative study of the three catalytically active forms of bismuth molybdate revealed similar findings with two of the three phases observed (by EDXRD) to form directly from a precursor gel with an Avrami-Erofe'ev kinetic analysis of the crystallisation process suggesting that the mechanisms of formation were different for each phase. Hydrothermal methods were also used to prepare cobalt and manganese substituted aluminophosphate structures API and AEI, which were found to be efficient catalysts for the methanol to olefin reaction. However, it was also observed that during calcination to remove the structure-directing agent, that some of the cobalt and manganese in the tetrahedral framework sites underwent oxidation from 2+ to 3+ although the extent of this was found to be dependent upon both structure type and metal ion. Finally an investigation was carried out into the use of ion-exchanged zeolites as precursors for the low temperature crystallisation of the spinel structure CoA12O4. The results from this study suggested that very small spinel particles formed within the XRD amorphous collapsed zeolites although both zeolite structure type and cobalt salt were thought to have an effect on phase formation.

  13. Non-enveloped HCV core protein as constitutive antigen of cold-precipitable immune complexes in type II mixed cryoglobulinaemia

    PubMed Central

    SANSONNO, D; LAULETTA, G; NISI, L; GATTI, P; PESOLA, F; PANSINI, N; DAMMACCO, F

    2003-01-01

    Hepatitis C virus (HCV) infection has been detected in a large proportion of patients with mixed cryoglobulinaemia (MC). Circulating ‘free’ non-enveloped HCV core protein has been demonstrated in HCV-infected patients, and this suggests its possible involvement in the formation of cryoprecipitable immune complexes (ICs). Thirty-two anti-HCV, HCV RNA-positive patients with type II MC were evaluated. Non-enveloped HCV core protein, HCV RNA sequences, total IgM, rheumatoid factor (RF) activity, IgG and IgG subclasses, C3 and C4 fractions, C1q protein and C1q binding activity were assessed in both cryoprecipitates and supernatants. Non-enveloped HCV core protein was demonstrated in 30 of 32 (93·7%) type II MC patients. After separation of cold-precipitable material, the protein was removed completely from supernatant in 12 patients (40%), whereas it was enriched in the cryoprecipitates of the remaining 18. In addition, HCV RNA and IgM molecules with RF activity were concentrated selectively in the cryoprecipitates. Differential precipitation was found for both total IgG and IgG subclasses, as they were less represented in the cryoglobulins and no selective enrichment was noted. Immunological characterization of HCV core protein-containing cryoprecipitating ICs after chromatographic fractionation showed that the IgM monoclonal component had RF activity, whereas anti-HCV core reactivity was confined to the IgG fraction. C1q enrichment in addition to high avidity of ICs for C1q binding in the cryoprecipitates suggest that complement activation may occur through the C1q protein pathway. The present data demonstrate that non-enveloped HCV core protein is a constitutive component of cryoprecipitable ICs in type II MC patients. PMID:12869035

  14. Developing the clinical components of a complex intervention for a glaucoma screening trial: a mixed methods study

    PubMed Central

    2011-01-01

    Background Glaucoma is a leading cause of avoidable blindness worldwide. Open angle glaucoma is the most common type of glaucoma. No randomised controlled trials have been conducted evaluating the effectiveness of glaucoma screening for reducing sight loss. It is unclear what the most appropriate intervention to be evaluated in any glaucoma screening trial would be. The purpose of this study was to develop the clinical components of an intervention for evaluation in a glaucoma (open angle) screening trial that would be feasible and acceptable in a UK eye-care service. Methods A mixed-methods study, based on the Medical Research Council (MRC) framework for complex interventions, integrating qualitative (semi-structured interviews with 46 UK eye-care providers, policy makers and health service commissioners), and quantitative (economic modelling) methods. Interview data were synthesised and used to revise the screening interventions compared within an existing economic model. Results The qualitative data indicated broad based support for a glaucoma screening trial to take place in primary care, using ophthalmic trained technical assistants supported by optometry input. The precise location should be tailored to local circumstances. There was variability in opinion around the choice of screening test and target population. Integrating the interview findings with cost-effectiveness criteria reduced 189 potential components to a two test intervention including either optic nerve photography or screening mode perimetry (a measure of visual field sensitivity) with or without tonometry (a measure of intraocular pressure). It would be more cost-effective, and thus acceptable in a policy context, to target screening for open angle glaucoma to those at highest risk but for both practicality and equity arguments the optimal strategy was screening a general population cohort beginning at age forty. Conclusions Interventions for screening for open angle glaucoma that would be

  15. Social cohesion through football: a quasi-experimental mixed methods design to evaluate a complex health promotion program

    PubMed Central

    2010-01-01

    The complexity of the Football United program poses challenges for measurement, and requires the study design to be responsive to the dynamic nature of the program and context. Assessment of change is needed at multiple levels, drawing on mixed methods and multidisciplinary approaches in implementation and evaluation. Attention to these challenges has underpinned the design and methods in the Social Cohesion through Football study, which will use a unique and innovative combination of measures that have not been applied together previously in social inclusion/cohesion and sport and social inclusion/cohesion program research. PMID:20920361

  16. Synthesis, spectroscopic characterization, electrochemical behavior and computational analysis of mixed diamine ligand gold(III) complexes: antiproliferative and in vitro cytotoxic evaluations against human cancer cell lines.

    PubMed

    Al-Jaroudi, Said S; Monim-ul-Mehboob, M; Altaf, Muhammad; Al-Saadi, Abdulaziz A; Wazeer, Mohammed I M; Altuwaijri, Saleh; Isab, Anvarhusein A

    2014-12-01

    The gold(III) complexes of the type [(DACH)Au(en)]Cl3, 1,2-Diaminocyclohexane ethylenediamine gold(III) chloride [where 1,2-DACH = cis-, trans-1,2- and S,S-1,2diaminocyclohexane and en = ethylenediamine] have been synthesized and characterized using various analytical and spectroscopic techniques including elemental analysis, UV-Vis and FTIR spectra; and solution as well as solid-state NMR measurements. The solid-state (13)C NMR shows that 1,2-diaminocyclohexane (1,2-DACH) and ethylenediamine (en) are strongly bound to the gold(III) center via N donor atoms. The stability of the mixed diamine ligand gold(III) was determined by (1)H and (13)C NMR spectra. Their electrochemical behavior was studied by cyclic voltammetry. The structural details and relative stabilities of the four possible isomers of the complexes were also reported at the B3LYP/LANL2DZ level of theory. The coordination sphere of these complexes around gold(III) center adopts distorted square planar geometry. The computational study also demonstrates that trans- conformations is slightly more stable than the cis-conformations. The antiproliferative effects and cytotoxic properties of the mixed diamine ligand gold(III) complexes were evaluated in vitro on human gastric SGC7901 and prostate PC3 cancer cells using MTT assay. The antiproliferative study of the gold(III) complexes on PC3 and SGC7901 cells indicate that complex 1 is the most effective antiproliferative agent among mixed ligand based gold(III) complexes 1-3. The IC50 data reveal that the in vitro cytotoxicity of complexes 1 and 3 against SGC7901 cancer cells are fairly better than that of cisplatin.

  17. Experimental study of complex mixed-mode oscillations generated in a Bonhoeffer-van der Pol oscillator under weak periodic perturbation.

    PubMed

    Shimizu, Kuniyasu; Sekikawa, Munehisa; Inaba, Naohiko

    2015-02-01

    Bifurcations of complex mixed-mode oscillations denoted as mixed-mode oscillation-incrementing bifurcations (MMOIBs) have frequently been observed in chemical experiments. In a previous study [K. Shimizu et al., Physica D 241, 1518 (2012)], we discovered an extremely simple dynamical circuit that exhibits MMOIBs. Our model was represented by a slow/fast Bonhoeffer-van der Pol circuit under weak periodic perturbation near a subcritical Andronov-Hopf bifurcation point. In this study, we experimentally and numerically verify that our dynamical circuit captures the essence of the underlying mechanism causing MMOIBs, and we observe MMOIBs and chaos with distinctive waveforms in real circuit experiments.

  18. Experimental study of complex mixed-mode oscillations generated in a Bonhoeffer-van der Pol oscillator under weak periodic perturbation

    SciTech Connect

    Shimizu, Kuniyasu; Sekikawa, Munehisa; Inaba, Naohiko

    2015-02-15

    Bifurcations of complex mixed-mode oscillations denoted as mixed-mode oscillation-incrementing bifurcations (MMOIBs) have frequently been observed in chemical experiments. In a previous study [K. Shimizu et al., Physica D 241, 1518 (2012)], we discovered an extremely simple dynamical circuit that exhibits MMOIBs. Our model was represented by a slow/fast Bonhoeffer-van der Pol circuit under weak periodic perturbation near a subcritical Andronov-Hopf bifurcation point. In this study, we experimentally and numerically verify that our dynamical circuit captures the essence of the underlying mechanism causing MMOIBs, and we observe MMOIBs and chaos with distinctive waveforms in real circuit experiments.

  19. Synthesis and spectroscopic studies of novel Cu(II), Co(II), Ni(II) and Zn(II) mixed ligand complexes with saccharin and nicotinamide

    NASA Astrophysics Data System (ADS)

    Çakır, S.; Bulut, İ.; Naumov, P.; Biçer, E.; Çakır, O.

    2001-01-01

    Four novel mixed ligand complexes of Cu(II), Co(II), Ni(II) and Zn(II) with saccharin and nicotinamide were synthesised and characterised on the basis of elemental analysis, FT-IR spectroscopic study, UV-Vis spectrometric and magnetic susceptibility data. The structure of the Cu (II) complex is completely different from those of the Co(II), Ni(II) and Zn(II) complexes. From the frequencies of the saccharinato CO and SO2 modes, it has been proven that the saccharinato ligands in the structure of the Cu complex are coordinated to the metal ion ([Cu(NA)2(Sac)2(H2O)], where NA - nicotinamide, Sac - saccharinato ligand or ion), whilst in the Co(II), Ni(II) and Zn(II) complexes are uncoordinated and exist as ions ([M(NA)2(H2O)4](Sac)2).

  20. Synthesis, crystal structures and properties of three new mixed-ligand d{sup 10} metal complexes constructed from pyridinecarboxylate and in situ generated amino-tetrazole ligand

    SciTech Connect

    Liu Dongsheng; Huang, Xihe; Huang Changcang; Huang Gansheng; Chen Jianzhong

    2009-07-15

    Three new metal-organic frameworks, [Zn(atz)(nic)]{sub n}(1), [Zn(atz)(isonic)]{sub n}.nHisonic(2) and [Cd(atz)(isonic)]{sub n}(3) (Hnic=nicotinic acid, Hisonic=isonicotinic acid), have been firstly synthesized by employing mixed-ligand of pyridinecarboxylate with the in situ generated ligand of 5-amino-tetrazolate(atz{sup -}), and characterized by elemental analysis, IR spectroscopy, TGA and single crystal X-ray diffraction. The results revealed that 1 presents a two-dimensional (2D) 'sql' topological network constructed from the linear chain subunit of Zn(nic){sub 2} and atz{sup -} ligand. A remarkable feature of 2 is a 2-fold interpenetrated diamondoid network with free Hisonic molecules locating in the channels formed by the zigzag chain subunits of Zn(isonic){sub 2}. Complex 3 is a 3D non-interpenetrated pillared framework constructed from the double chain subunits of Cd-COO{sup -}Cd. It possesses a rarely observed (4,6)-connected 'fsc' topology. The thermal stabilities and fluorescent properties of the complexes were investigated. All of these complexes exhibited intense fluorescent emissions in the solid state at room temperature. - Graphical abstract: Three new mixed-ligand d{sup 10} metal complexes have been synthesized by employing mixed-ligand synthetic approach. Complex 1 presents a 2D 'sql' topological network. Complex 2 is a 2-fold interpenetrated diamondoid network with microporous channels. Rarely observed (4,6)-connected 'fsc' topological network was found in complex 3.

  1. Newer mixed ligand Schiff base complexes from aquo-N-(2‧-hydroxy acetophenone) glycinatocopper(II) as synthon: DFT, antimicrobial activity and molecular docking study

    NASA Astrophysics Data System (ADS)

    Pramanik, Harun A. R.; Das, Dharitri; Paul, Pradip C.; Mondal, Paritosh; Bhattacharjee, Chira R.

    2014-02-01

    Synthesis of a series of newer mixed ligand copper(II) complexes of aminoacid Schiff base of the type [CuL(X)] (L = N-(2‧-hydroxy acetophenone) glycinate, X = imidazole (im) 2, benzimidazole (benz) 3, pyridine (py) 4, hydrazine (hz) 5,8-hydroxyquinoline (8-hq) 6, pyrrolidine (pyrr) 7, piperidine (pip) 8, and nicotinamide (nic) 9) have been accomplished from the interaction of an aquated Schiff base complex, [CuL(H2O)]·H2O, 1 with some selected neutral nitrogen-donor ligands. The copper(II) Schiff base complex, [CuL(H2O)]·H2O, L = N-(2‧-hydroxy acetophenone) glycinate was synthesized from the reaction of glycine and 2‧ hydroxy acetophenone and copper(II) acetate. The compounds were characterised by elemental analysis, spectral, magnetic and thermal studies. The density functional theory calculations were performed using LANL2DZ and 6-311 G(d, p) basis sets with B3LYP correlation functional to ascertain the stable electronic structure, HOMO-LUMO energy gap, chemical hardness and dipole moment of the mixed ligand complexes. A distorted square planar geometry has been conjectured for the complexes. Antibacterial activities of the ligand and its metal complexes have been tested against selected gram-positive and gram-negative strains and correlated with computational docking scores.

  2. U1-RNP and TLR receptors in the pathogenesis of mixed connective tissue diseasePart I. The U1-RNP complex and its biological significance in the pathogenesis of mixed connective tissue disease.

    PubMed

    Paradowska-Gorycka, Agnieszka

    2015-01-01

    Mixed connective tissue disease (MCTD) is a rare autoimmune syndrome, signified by complex interactions between disease-related phenomena, including inflammation, proliferative vascular arteriopathy, thrombotic events and humoral autoimmune processes. It is still controversial whether MCTD is a distinct clinical entity among systemic connective tissue diseases, although several authors consider that it is distinct and underline characteristic, distinct clinical, serological and immunogenetic features. The putative target of autoimmunity in MCTD is U1-RNP, which is a complex of U1-RNA and small nuclear RNP. Both the U1-RNA component and the specific proteins, particularly U1-70K, engage immune cells and their receptors in a complex network of interactions that ultimately lead to autoimmunity, inflammation, and tissue injury. U1-RNA is capable of inducing manifestations consistent with TLR activation. Stimulation of innate immunity by native RNA molecules with a double-stranded secondary structure may help explain the high prevalence of autoimmunity to RNA binding proteins.

  3. Mixed Methods Research in the Development and Evaluation of Complex Interventions in Palliative and End-of-Life Care: Report on the MORECare Consensus Exercise

    PubMed Central

    Preston, Nancy; Evans, Catherine J.; Grande, Gunn; Short, Vicky; Benalia, Hamid; Higginson, Irene J.; Todd, on behalf of MORECare, Chris

    2013-01-01

    Abstract Background: Complex interventions are common in palliative and end-of-life care. Mixed methods approaches sit well within the multiphase model of complex intervention development and evaluation. Generic mixed methods guidance is useful but additional challenges in the research design and operationalization within palliative and end-of-life care may have an impact on the use of mixed methods. Objective: The objective of the study was to develop guidance on the best methods for combining quantitative and qualitative methods for health and social care intervention development and evaluation in palliative and end-of-life care. Methods: A one-day workshop was held where experts participated in facilitated groups using Transparent Expert Consultation to generate items for potential recommendations. Agreement and consensus were then sought on nine draft recommendations (DRs) in a follow-up exercise. Results: There was at least moderate agreement with most of the DRs, although consensus was low. Strongest agreement was with DR1 (usefulness of mixed methods to palliative and end-of-life care) and DR5 (importance of attention to respondent burden), and least agreement was with DR2 (use of theoretical perspectives) and DR6 (therapeutic effects of research interviews). Narrative comments enabled recommendation refinement. Two fully endorsed, five partially endorsed, and two refined DRs emerged. The relationship of these nine to six key challenges of palliative and end-of-life care research was analyzed. Conclusions: There is a need for further discussion of these recommendations and their contribution to methodology. The recommendations should be considered when designing and operationalizing mixed methods studies of complex interventions in palliative care, and because they may have wider relevance, should be considered for other applications. PMID:24195755

  4. Mixed methods research in the development and evaluation of complex interventions in palliative and end-of-life care: report on the MORECare consensus exercise.

    PubMed

    Farquhar, Morag; Preston, Nancy; Evans, Catherine J; Grande, Gunn; Short, Vicky; Benalia, Hamid; Higginson, Irene J; Todd, Chris

    2013-12-01

    Complex interventions are common in palliative and end-of-life care. Mixed methods approaches sit well within the multiphase model of complex intervention development and evaluation. Generic mixed methods guidance is useful but additional challenges in the research design and operationalization within palliative and end-of-life care may have an impact on the use of mixed methods. The objective of the study was to develop guidance on the best methods for combining quantitative and qualitative methods for health and social care intervention development and evaluation in palliative and end-of-life care. A one-day workshop was held where experts participated in facilitated groups using Transparent Expert Consultation to generate items for potential recommendations. Agreement and consensus were then sought on nine draft recommendations (DRs) in a follow-up exercise. There was at least moderate agreement with most of the DRs, although consensus was low. Strongest agreement was with DR1 (usefulness of mixed methods to palliative and end-of-life care) and DR5 (importance of attention to respondent burden), and least agreement was with DR2 (use of theoretical perspectives) and DR6 (therapeutic effects of research interviews). Narrative comments enabled recommendation refinement. Two fully endorsed, five partially endorsed, and two refined DRs emerged. The relationship of these nine to six key challenges of palliative and end-of-life care research was analyzed. There is a need for further discussion of these recommendations and their contribution to methodology. The recommendations should be considered when designing and operationalizing mixed methods studies of complex interventions in palliative care, and because they may have wider relevance, should be considered for other applications.

  5. Modeling of Flow, Transport and Controlled Sedimentation Phenomena during Mixing of Salt Solutions in Complex Porous Formations

    NASA Astrophysics Data System (ADS)

    Skouras, Eugene D.; Jaho, Sofia; Pavlakou, Efstathia I.; Sygouni, Varvara; Petsi, Anastasia; Paraskeva, Christakis A.

    2015-04-01

    The deposition of salts in porous media is a major engineering phenomenon encountered in a plethora of industrial and environmental applications where in some cases is desirable and in other not (oil production, geothermal systems, soil stabilization etc). Systematic approach of these problems requires knowledge of the key mechanisms of precipitating salts within the porous structures, in order to develop new methods to control the process. In this work, the development and the solution of spatiotemporally variable mass balances during salt solution mixing along specific pores were performed. Both analytical models and finite differences CFD models were applied for the study of flow and transport with simultaneous homogeneous and heterogeneous nucleation (by crystal growth on the surface of the pores) in simple geometries, while unstructured finite elements and meshless methods were developed and implemented for spatial discretization, reconstruction, and solution of transport equations and homogeneous / heterogeneous reactions in more complex geometries. At initial stages of this work, critical problem parameters were identified, such as the characteristics of the porosity, the number of dissolved components, etc. The parameters were then used for solving problems which correspond to available experimental data. For each combination of ions and materials, specific data and process characteristics were included: (a) crystal kinetics (nucleation, growth rates or reaction surface rates of crystals, critical suspension concentrations), (b) physico-chemical properties (bulk density, dimensions of generated crystals, ion diffusion coefficients in the solution), (c) operating parameters (macroscopic velocity, flow, or pressure gradient of the solution, ion concentration) (d) microfluidic data (geometry, flow area), (e) porosity data in Darcy description (initial porosity, specific surface area, tortuosity). During the modeling of flow and transport in three

  6. Evaluating complex health financing interventions: using mixed methods to inform further implementation of a novel PBI intervention in rural Malawi.

    PubMed

    McMahon, Shannon A; Brenner, Stephan; Lohmann, Julia; Makwero, Christopher; Torbica, Aleksandra; Mathanga, Don P; Muula, Adamson S; De Allegri, Manuela

    2016-08-19

    Gaps remain in understanding how performance-based incentive (PBI) programs affect quality of care and service quantity, whether programs are cost effective and how programs could be tailored to meet client and provider needs while remaining operationally viable. In 2014, Malawi's Ministry of Health launched the Service Delivery Integration-PBI (SSDI-PBI) program. The program is unique in that no portion of performance bonuses are paid to individual health workers, and it shifts responsibility for infrastructure and equipment procurement from facility staff to implementing partners. This protocol outlines an approach that analyzes processes and outcomes, considers expected and unexpected consequences of the program and frames the program's outputs relative to its costs. Findings from this evaluation will inform the intended future scale-up of PBI in Malawi. This study employs a prospective controlled before-and-after triangulation design to assess effects of the PBI program by analyzing quantitative and qualitative data from intervention and control facilities. Guided by a theoretical framework, the evaluation consists of four main components: service provision, health worker motivation, implementation processes and costing. Quality and access outcomes are assessed along four dimensions: (1) structural elements (related to equipment, drugs, staff); (2) process elements (providers' compliance with standards); (3) outputs (service utilization); (4) experiential elements (experiences of service delivery). The costing component includes costs related to start-up, ongoing management, and the cost of incentives themselves. The cost analysis considers costs incurred within the Ministry of Health, funders, and the implementing agency. The evaluation relies on primary data (including interviews and surveys) and secondary data (including costing and health management information system data). Through the lens of a PBI program, we illustrate how complex interventions can be

  7. Mixed N-Heterocyclic Carbene-Bis(oxazolinyl)borato Rhodium and Iridium Complexes in Photochemical and Thermal Oxidative Addition Reactions

    SciTech Connect

    Xu, Songchen; Manna, Kuntal; Ellern, Arkady; Sadow, Aaron D

    2014-12-08

    In order to facilitate oxidative addition chemistry of fac-coordinated rhodium(I) and iridium(I) compounds, carbene–bis(oxazolinyl)phenylborate proligands have been synthesized and reacted with organometallic precursors. Two proligands, PhB(OxMe2)2(ImtBuH) (H[1]; OxMe2 = 4,4-dimethyl-2-oxazoline; ImtBuH = 1-tert-butylimidazole) and PhB(OxMe2)2(ImMesH) (H[2]; ImMesH = 1-mesitylimidazole), are deprotonated with potassium benzyl to generate K[1] and K[2], and these potassium compounds serve as reagents for the synthesis of a series of rhodium and iridium complexes. Cyclooctadiene and dicarbonyl compounds {PhB(OxMe2)2ImtBu}Rh(η4-C8H12) (3), {PhB(OxMe2)2ImMes}Rh(η4-C8H12) (4), {PhB(OxMe2)2ImMes}Rh(CO)2 (5), {PhB(OxMe2)2ImMes}Ir(η4-C8H12) (6), and {PhB(OxMe2)2ImMes}Ir(CO)2 (7) are synthesized along with ToMM(η4-C8H12) (M = Rh (8); M = Ir (9); ToM = tris(4,4-dimethyl-2-oxazolinyl)phenylborate). The spectroscopic and structural properties and reactivity of this series of compounds show electronic and steric effects of substituents on the imidazole (tert-butyl vs mesityl), effects of replacing an oxazoline in ToM with a carbene donor, and the influence of the donor ligand (CO vs C8H12). The reactions of K[2] and [M(μ-Cl)(η2-C8H14)2]2 (M = Rh, Ir) provide {κ4-PhB(OxMe2)2ImMes'CH2}Rh(μ-H)(μ-Cl)Rh(η2-C8H14)2 (10) and {PhB(OxMe2)2ImMes}IrH(η3-C8H13) (11). In the former compound, a spontaneous oxidative addition of a mesityl ortho-methyl to give a mixed-valent dirhodium species is observed, while the iridium compound forms a monometallic allyl hydride. Photochemical reactions of dicarbonyl compounds 5 and 7 result in C–H bond oxidative addition providing the compounds {κ4-PhB(OxMe2)2ImMes'CH2}RhH(CO) (12) and {PhB(OxMe2)2ImMes}IrH(Ph)CO (13). In 12, oxidative addition results in cyclometalation of the mesityl ortho-methyl similar to 10, whereas the iridium compound reacts with the benzene solvent to give a rare crystallographically characterized cis

  8. Synthesis, spectral, thermal and biological studies of mixed ligand complexes with newly prepared Schiff base and 1,10-phenanthroline ligands

    NASA Astrophysics Data System (ADS)

    Abd El-Halim, Hanan F.; Mohamed, Gehad G.; Khalil, Eman A. M.

    2017-10-01

    A series of mixed ligand complexes were prepared from the Schiff base (L1) as a primary ligand, prepared by condensation of oxamide and furan-2-carbaldehyde, and 1,10-phenanthroline (1,10-phen) as a secondary ligand. The Schiff base ligand and its mixed ligand chelates were characterized based on elemental analysis, IR, 1H NMR, thermal analysis, UV-Visible, mass, molar conductance, magnetic moment. X-ray diffraction, solid reflectance and ESR also have been studied. The mixed ligand complexes were found to have the formulae of [M(L1) (1,10-phen)]Clm.nH2O (M = Cr(III) and Fe(III) (m = 3) (n = 0); M = Mn(II), Cu(II) and Cd(II) (m = 2) (n = 0); and M = Co(II) (m = 2) (n = 1), Ni(II) (m = 2) (n = 2) and Zn(II) (m = 2) (n = 3)) and that the geometrical structure of the complexes were octahedral. The parameters of thermodynamic using Coats-Redfern and Horowitz-Metzger equations were calculated. The synthesized Schiff base ligand, 1,10-phenanthroline ligand and Their mixed ligand complexes were also investigated for their antibacterial and antifungal activity against bacterial species (Gram-Ve bacteria: Pseudomonas aeruginosa and Escherichia coli) and (Gram + Ve bacteria: Bacillus subtilis and Streptococcus pneumonia) and fungi (Aspergillus fumigates and Candida albicans). The anticancer activity of the new compounds had been tested against breast (MFC7) and colon (HCT-116) cell lines. The results showed high activity for the synthesized compounds.

  9. Pressure effects and Mössbauer spectroscopic studies on a 3D mixed-valence iron spin-crossover complex with NiAs topology.

    PubMed

    Bai, Yue-Ling; Tao, Jun; Huang, Rong-Bin; Zheng, Lan-Sun; Zheng, Shao-Liang; Oshida, Kazuyoshi; Einaga, Yasuaki

    2008-04-21

    A three-dimensional mixed-valence iron complex with NiAs-type topology, [(Fe(III)(3)O)Fe(II)(TA)(6)(H(2)O)(3)].(ClO(4))(2)(NO(3))(EtOH)(H(2)O)(2) (1, HTA = tetrazole-1H-acetic acid), shows spin-crossover behavior that was characterized via variable-temperature crystal structures, Mössbauer spectra and magnetic susceptibilities, the pressure effects on the transition behavior were also studied.

  10. Synthesis, characterization and antimicrobial activities of mixed ligand transition metal complexes with isatin monohydrazone Schiff base ligands and heterocyclic nitrogen base

    NASA Astrophysics Data System (ADS)

    Devi, Jai; Batra, Nisha

    2015-01-01

    Mixed ligand complexes of Co(II), Ni(II), Cu(II) and Zn(II) with various uninegative tridentate ligands derived from isatin monohydrazone with 2-hydroxynapthaldehyde/substituted salicylaldehyde and heterocyclic nitrogen base 8-hydroxyquinoline have been synthesized and characterized by elemental analysis, conductometric studies, magnetic susceptibility and spectroscopic techniques (IR, UV-VIS, NMR, mass and ESR). On the basis of these characterizations, it was revealed that Schiff base ligands existed as monobasic tridentate ONO bonded to metal ion through oxygen of carbonyl group, azomethine nitrogen and deprotonated hydroxyl oxygen and heterocyclic nitrogen base 8-hydroxyquinoline existed as monobasic bidentate ON bonded through oxygen of hydroxyl group and nitrogen of quinoline ring with octahedral or distorted octahedral geometry around metal ion. All the compounds have been tested in vitro against various pathogenic Gram positive bacteria, Gram negative bacteria and fungi using different concentrations (25, 50, 100, 200 μg/mL) of ligands and their complexes. Comparative study of antimicrobial activity of ligands, and their mixed complexes indicated that complexes exhibit enhanced activity as compared to free ligands and copper(II) Cu(LIV)(Q)ṡH2O complex was found to be most potent antimicrobial agent.

  11. Enhancement of lanthanide evaporation by complexation: Dysprosium tri-iodide mixed with indium iodide and thulium tri-iodide mixed with thallium iodide

    SciTech Connect

    Curry, J. J.; Henins, A.; Hardis, J. E.; Estupiñán, E. G.; Lapatovich, W. P.; Shastri, S. D.

    2013-09-28

    The vapors in equilibrium with condensates of DyI{sub 3}, DyI{sub 3}/InI, TmI{sub 3}, and TmI{sub 3}/TlI were observed over the temperature range from 900 K to 1400 K using x-ray induced fluorescence. The total densities of each element (Dy, Tm, In, Tl, and I) in the vapor, summed over all atomic and molecular species, were determined. Dramatic enhancements in the total vapor densities of Dy and Tm were observed in the vapors over DyI{sub 3}/InI and TmI{sub 3}/TlI as compared to the vapors over pure DyI{sub 3} and pure TmI{sub 3}, respectively. An enhancement factor exceeding 10 was observed for Dy at T≈ 1020 K, decreasing to 0 at T≈ 1250 K. An enhancement factor exceeding 20 was observed for Tm at T≈ 1040 K, decreasing to 0 at T≈ 1300 K. Such enhancements are expected from the formation of the vapor-phase hetero-complexes DyInI{sub 4} and TmTlI{sub 4}. Numerical simulations of the thermo-chemical equilibrium suggest the importance of additional complexes in liquid phases. A description of the measurement technique is given. Improvements in the absolute calibration lead to an approximately 40% correction to previously reported preliminary results [J. J. Curry et al., Chem. Phys. Lett. 507, 52 (2011); Appl. Phys. Lett. 100, 083505 (2012)].

  12. Hornblende gabbro sill complex at Onion Valley, California, and a mixing origin for the Sierra Nevada batholith

    NASA Astrophysics Data System (ADS)

    Sisson, T. W.; Grove, T. L.; Coleman, D. S.

    1996-12-01

    The steep crest of the Sierra Nevada, California, near Onion Valley, exposes natural cross sections through a mafic intrusive complex that formed as part of the Mesozoic Sierra Nevada batholith. Sheeted sills of hornblende gabbro to hornblende diorite, individually as thick as 1.5 m, form the upper 200 to 300 m of the complex. Thicker, multiply-injected sills, as well as mafic stocks, lie underneath at elevations below 3600 m. Lens-shaped cumulate bodies, as thick as 200 m and more than 700 m broad, lie near the base of the sheeted sill suite. Cumulates are flat-lying, modally layered hornblende gabbro with subsidiary ultramafic olivine hornblendite, plagioclase hornblendite, and late-mobile hornblende-plagioclase pegmatite. Fine grain size, scarce phenocrysts and xenocrysts, and quench mineral textures are evidence that hornblende gabbro sills injected in a largely liquid state and preserve basaltic melt compositions. Most sills reached volatile saturation, as shown by tiny miarolitic cavities that are also widespread in cumulates. Although some sills chilled directly against others, most chilled against septa, millimeters to a few centimeters thick, of medium-grained diorite to granodiorite. Mutually crosscutting relations, as well as chilling, show that the septa were partly molten at the time the sills injected and likely formed the lower portions of an overlying more silicic magma chamber that has since been removed by erosion. Sill compositions range from evolved high-alumina basalt to aluminous andesite with major and trace element abundances similar to those of modern arc magmas. Experimental phase equilibria indicate dissolved water contents near 6 wt% (Sisson and Grove 1993a). The sills show unequivocally that hydrous arc basaltic magmas reached shallow levels in the crust during formation of the largely granodioritic Sierra Nevada batholith. The basaltic magmas appear to have been produced from an enriched mantle source with 87Sr/86Sr ˜0.7065, ɛNd ˜-4

  13. Supramolecular structure and spectral studies on mixed-ligand complexes derived from β-diketone with azodye rhodanine derivatives.

    PubMed

    El-Sonbati, A Z; Diab, M A; Belal, A A M; Morgan, Sh M

    2012-12-01

    A novel method to synthesize some mononuclear ternary palladium(II) complexes of the general formula [Pd(L(n))L] (where LH=diketone=acetylacetone, HL(n)=azorhodanine) has been synthesize. The structure of the new mononuclear ternary palladium(II) complexes was characterized using elemental analysis, spectral (electronic, infrared and (1)H &(13)C NMR) studies, magnetic susceptibility measurements and thermal studies. The IR showed that the ligands (HL(n) & LH) act as monobasic bidentate through the azodye nitrogen, oxygen keto moiety and two enolato oxygen atoms. The molar conductivities show that all the complexes are non-electrolytes. Bidentate chelating nature of β-diketone and azorhodanine anions in the complexes was characterized by (electronic, infrared and (1)H &(13)C NMR) spectra. Square planar geometry around palladium has been assigned in all complexes. Various ligand and nephelouxetic parameter have been calculated for the complexes. The thermal decomposition for complexes was studied.

  14. Supramolecular structure and spectral studies on mixed-ligand complexes derived from β-diketone with azodye rhodanine derivatives

    NASA Astrophysics Data System (ADS)

    El-Sonbati, A. Z.; Diab, M. A.; Belal, A. A. M.; Morgan, Sh. M.

    2012-12-01

    A novel method to synthesize some mononuclear ternary palladium(II) complexes of the general formula [Pd(Ln)L] (where LH = diketone = acetylacetone, HLn = azorhodanine) has been synthesize. The structure of the new mononuclear ternary palladium(II) complexes was characterized using elemental analysis, spectral (electronic, infrared and 1H &13C NMR) studies, magnetic susceptibility measurements and thermal studies. The IR showed that the ligands (HLn & LH) act as monobasic bidentate through the azodye nitrogen, oxygen keto moiety and two enolato oxygen atoms. The molar conductivities show that all the complexes are non-electrolytes. Bidentate chelating nature of β-diketone and azorhodanine anions in the complexes was characterized by (electronic, infrared and 1H &13C NMR) spectra. Square planar geometry around palladium has been assigned in all complexes. Various ligand and nephelouxetic parameter have been calculated for the complexes. The thermal decomposition for complexes was studied.

  15. Magma mixing in the Kalaqin core complex, northern North China Craton: Linking deep lithospheric destruction and shallow extension

    NASA Astrophysics Data System (ADS)

    Fu, Lebing; Wei, Junhao; Tan, Jun; Santosh, M.; Zhang, Daohan; Chen, Jiajie; Li, Yanjun; Zhao, Shaoqing; Peng, Lina

    2016-09-01

    .4, T2DM(Nd)Group 1 = 1705-1775 Ma, (87Sr/86Sr)iGroup 2 = 0.70586-0.70587, εNd(t)Group 2 = - 0.6 to - 0.7, T2DM(Nd)Group 2 = 971-978 Ma, and εHf(t)Group 2 = - 4.5 to - 10.0. The mineralogical and geochemical features suggest that the host Jiguanzi adamellite and Group 2 enclaves were generated through synchronous mixing and fractional crystallization accompanied by mechanical and chemical exchanges. The Group 1 enclaves showing cogenetic affinity with their felsic host represent the mechanical concentrations of mafic minerals and accessory phases from evolved hybrid host magma. Magma sources of the host Jiguanzi adamellite and its Group 1 enclaves are dominated by lower crust (LCC) components, whereas those for the Group 2 enclaves are dominated by metasomatized lithospheric mantle. The magma genesis involved complex multi-stage crust-mantle interaction processes including: (1) lithospheric mantle modification induced by Triassic subduction of the Paleo-Asian Ocean slab and/or Triassic-Cretaceous asthenospheric melt underplating; and (2) melting of the ancient LCC and lithospheric mantle, and hybridization of mantle- and crust-derived melts. In conjunction with regional geological and geochemical data, we argue that the Late Jurassic-Early Cretaceous shallow extension events represented by the Kalaqin MCC triggered deep-seated multi-stage magmatism and lithospheric destruction, and the continuous generation of magma further strengthened the extension and result in more extensive lithospheric thinning.

  16. A thermodynamic study of complexation process between N, N'-dipyridoxylidene(1,4-butanediamine) and Cd2+ in some binary mixed solvents using conductometry

    NASA Astrophysics Data System (ADS)

    Ebrahimpoor, Sonia; Khoshnood, Razieh Sanavi; Beyramabadi, S. Ali

    2016-12-01

    Complexation of the Cd2+ ion with N, N'-dipyridoxylidene(1,4-butanediamine) Schiff base was studied in pure solvents including acetonitrile (AN), ethanol (EtOH), methanol (MeOH), tetrahydrofuran (THF), dimethylformamide (DMF), water (H2O), and various binary solvent mixtures of acetonitrile-ethanol (AN-EtOH), acetonitrile-methanol (AN-MeOH), acetonitrile-tetrahydrofuran (AN-THF), acetonitrile-dimethylformamide (AN-DMF), and acetonitrile-water (AN-H2O) systems at different temperatures using the conductometric method. The conductance data show that the stoichiometry of complex is 1: 1 [ML] in all solvent systems. A non-linear behavior was observed for changes of log K f of [Cd( N, N'-dipyridoxylidene(1,4-butanediamine)] complex versus the composition of the binary mixed solvents, which was explained in terms of solvent-solvent interactions. The results show that the thermodynamics of complexation reaction is affected by the nature and composition of the mixed solvents.

  17. Selective enrichment media bias the types of salmonella enterica strains isolated from mixed strain cultures and complex enrichment broths

    USDA-ARS?s Scientific Manuscript database

    For foodborne outbreak investigations it can be difficult to isolate the relevant strain from food and/or environmental sources. If the sample is contaminated by more than one strain of the organism the relevant strain might be missed. In this study mixed cultures of Salmonella enterica were grown...

  18. Quantities and characteristics of the contact-handled low-level mixed waste streams for the DOE complex

    SciTech Connect

    Huebner, T.L.; Wilson, J.M.; Ruhter, A.H.; Bonney, S.J.

    1994-08-01

    This report supports the Integrated Thermal Treatment System (ITTS) Study initiated by the Department of Energy (DOE) Office of Technology Development (EM-50), which is a system engineering assessment of a variety of mixed waste treatment process. The DOE generates and stores large quantities of mixed wastes that are contaminated with both chemically hazardous and radioactive species. The treatment of these mixed wastes requires meeting the standards established by the Environmental Protection Agency for the specific hazardous contaminants regulated under the Resource Conservation and Recovery Act while also providing adequate control of the radionuclides. The thrust of the study is to develop preconceptual designs and life-cycle cost estimates for integrated thermal treatment systems ranging from conventional incinerators, such as rotary kiln and controlled air systems, to more innovative but not yet established technologies, such as molten salt and molten metal waste destruction systems. Prior to this engineering activity, the physical and chemical characteristics of the DOE low-level mixed waste streams to be treated must be defined or estimated. This report describes efforts to estimate the DOE waste stream characteristics.

  19. Solution study of a structurally characterized monoalkoxo-bound monooxo-vanadium(V) complex: spontaneous generation of the corresponding oxobridged divanadium(V,V) complex and its electroreduction to a mixed-valence species in solution.

    PubMed

    Dinda, Rupam; Sengupta, Parbati; Sutradhar, Manas; Mak, Thomas C W; Ghosh, Saktiprosad

    2008-07-07

    An interesting transformation of a structurally characterized monooxoalkoxovanadium(V) complex [VO(OEt)L] (LH 2 = a dibasic tridentate ONO donor ligand) in solution leading to the formation of the corresponding monooxobridged divanadium(V,V) complex (VOL) 2O is reported. This binuclear species in solution is adequately characterized by elemental analysis, measurement of conductance (in solution), various spectroscopic (UV-vis, IR, NMR, and mass spectrometry) techiniques and by cyclic voltammetry. The corresponding mixed-valence vanadium(IV,V) species has been generated in CH 3CN solution by controlled potential electrolysis of (VOL) 2O. This mixed-valence species is identified and studied by EPR technique (at room temperature and at liquid nitrogen temperature) and also by UV-vis spectroscopy. This study may be regarded as a general method of obtaining monooxo-bridged binuclear vanadium(V,V) species from the corresponding mononuclear monooxoalkoxovanadium(V) complexes of some selected dibasic tridentate ONO chelating ligands, which can be utilized as the precursor of monooxobridged divanadium(IV,V) mixed-valence species in solution obtainable by controlled potential electrolysis.

  20. Electrochemical synthesis and structural characterization of a novel mixed-valence copper(I)-copper(II) complex: {[bis(ethylenediamine)copper(II)] bis[diiodocuprate(I)]}.

    PubMed

    Fotouhi, Lida; Dehghanpour, Saeed; Heravi, Majid M; Ardakani, Mahboobeh Dashti

    2007-07-12

    A novel, mixed-valent copper(I)-copper(II) complex, {[bis(ethylene-diamine)copper(II)] bis[diiodocuprate(I)]} (1), has been prepared by electrochemical dissolution of a sacrificial copper anode in a solution of ethylenediamine (en), I2 and tetraethylammoniumperchlorate (TEAP) as supporting electrolyte in acetonitrile (AcN)and characterized by single-crystal X-ray structure determination. The crystal structure of the complex 1 shows that it consists of a CuI2 polymer formed from I- ligands bridging Cu(I) ions, with a nearly square planar geometry of bivalent Cu(II) atoms chelated by two ethylenediamine ligands. The results also show that direct electrosynthesis of the complex had high current efficiency, purity and electrolysis yield.

  1. Chitosan supported Zn(II) mixed ligand complexes as heterogeneous catalysts for one-pot synthesis of amides from ketones via Beckmann rearrangement

    NASA Astrophysics Data System (ADS)

    Anuradha; Kumari, Shweta; Layek, Samaresh; Pathak, Devendra D.

    2017-02-01

    Chitosan supported Zn(II) mixed ligand complexes have been synthesized and characterized by FT-IR, UV-Vis, TGA, XRD, FESEM, EDX, AAS and Elemental Analysis. These complexes have been found to be efficient and recyclable heterogeneous catalysts for the one-pot synthesis of amides via Beckmann rearrangement. All three complexes can be easily filtered out from the reaction medium and reused up to five times without significant loss of catalytic activity. The reported protocol is economical and novel in the sense that amides can be easily synthesized in only one-step. All products were obtained as white to off-white crystalline solids and fully characterized by 1H NMR, FT-IR and Mass Spectra.

  2. Norfloxacin and N-Donor Mixed-Ligand Copper(II) Complexes: Synthesis, Albumin Interaction, and Anti-Trypanosoma cruzi Activity

    PubMed Central

    Martins, Darliane A.; Gouvea, Ligiane R.; Muniz, Gabriel S. Vignoli; Louro, Sonia R. W.; Batista, Denise da Gama Jaen; Soeiro, Maria de Nazaré C.; Teixeira, Letícia R.

    2016-01-01

    Copper(II) complexes with the first-generation quinolone antibacterial agent norfloxacin containing a nitrogen donor heterocyclic ligand 2,2′-bipyridine (bipy) or 1,10-phenanthroline (phen) were prepared and characterized by IR, EPR spectra, molar conductivity, and elemental analyses. The experimental data suggest that norfloxacin was coordinated to copper(II) through the carboxylato and ketone oxygen atoms. The interaction of the copper(II) complexes with bovine serum albumin (BSA) and human serum albumin (HSA) was investigated using fluorescence quenching of the tryptophan residues and copper(II) EPR spectroscopy. The results of fluorescence titration revealed that copper(II) complexes have a moderate ability to quench the intrinsic fluorescence of the albumins through a static quenching mechanism. EPR experiments showed that BSA and HSA Cu(II) sites compete with NOR for Cu(II)-bipy and Cu(II)-phen to form protein mixed-ligand complexes. Copper(II) complexes, together with the corresponding ligands, were evaluated for their trypanocidal activity in vitro against Trypanosoma cruzi, the causative agent of Chagas disease. The tests performed using bloodstream trypomastigotes showed that the Cu(II)-N-donor precursors and the metal complexes were more active than the free fluoroquinolone. PMID:26924953

  3. Thermal, spectroscopic, and solvent influence studies on mixed-ligand copper(II) complexes containing the bulky ligand: Bis[N-(p-tolyl)imino]acenaphthene.

    PubMed

    El-Ayaan, Usama; Gabr, I M

    2007-05-01

    Four mixed-ligand copper(II) complexes containing the rigid bidentate nitrogen ligand bis[N-(p-tolyl)imino]acenaphthene (abb. p-Tol-BIAN) ligand are reported. These complexes, namely [Cu(p-Tol-BIAN)(2)](ClO(4))(2)1, [Cu(p-Tol-BIAN)(acac)](ClO(4)) 2, [Cu(p-Tol-BIAN)Cl(2)] 3 and [Cu(p-Tol-BIAN)(AcOH)(2)](ClO(4))(2)4 (where acac, acetylacetonate and AcOH, acetic acid) have been prepared and characterized by elemental analysis, spectroscopic, magnetic and molar conductance measurements. ESR spectra suggest a square planar geometry for complexes 1 and 2. In complexes 3 and 4, a distorted tetrahedral arrangement around copper(II) centre was suggested. Solvatochromic behavior of all studied complexes indicates strong solvatochromism of their solutions. The observed solvatochromism is mainly due to the solute-solvent interaction between the chelate cation and the solvent molecules. Thermal properties and decomposition kinetics of all complexes are investigated. The kinetic parameters (E, A, Delta H, Delta S and Delta G) of all thermal decomposition stages have been calculated using the Coats-Redfern and other standard equations.

  4. Syntheses, crystal structures, and characterization of three 1D, 2D and 3D complexes based on mixed multidentate N- and O-donor ligands

    SciTech Connect

    Yang, Huai-Xia; Liang, Zhen; Hao, Bao-Lian; Meng, Xiang-Ru

    2014-10-15

    Three new 1D to 3D complexes, namely, ([Ni(btec)(Himb){sub 2}(H{sub 2}O){sub 2}]·6H{sub 2}O){sub n} (1), ([Cd(btec){sub 0.5}(imb)(H{sub 2}O)]·1.5H{sub 2}O){sub n} (2), and ([Zn(btec){sub 0.5}(imb)]·H{sub 2}O){sub n} (3) (H{sub 4}btec=1,2,4,5-benzenetetracarboxylic acid, imb=2-(1H-imidazol-1-methyl)-1H-benzimidazole) have been synthesized by adjusting the central metal ions. Single-crystal X-ray diffraction analyses reveal that complex 1 possesses a 1D chain structure which is further extended into the 3D supramolecular architecture via hydrogen bonds. Complex 2 features a 2D network with Schla¨fli symbol (5{sup 3}·6{sup 2}·7)(5{sup 2}·6{sup 4}). Complex 3 presents a 3D framework with a point symbol of (4·6{sup 4}·8)(4{sup 2}·6{sup 2}·8{sup 2}). Moreover, their IR spectra, PXRD patterns, thermogravimetric curves, and luminescent emissions were studied at room temperature. - Graphical abstract: Three new 1D to 3D complexes with different structural and topological motifs have been obtained by modifying the central metal ions. Additionally, their IR, TG analyses and fluorescent properties are also investigated. - Highlights: • Three complexes based on mixed multidentate N- and O-donor ligands. • The complexes are characterized by IR, luminescence and TGA techniques. • Benzenetetracarboxylates display different coordination modes in complexes 1–3. • Changing the metal ions can result in complexes with completely different structures.

  5. Theoretical calculations, DNA interaction, topoisomerase I and phosphatidylinositol-3-kinase studies of water soluble mixed-ligand nickel(II) complexes.

    PubMed

    Gurumoorthy, Perumal; Mahendiran, Dharmasivam; Kalilur Rahiman, Aziz

    2016-03-25

    Eight water soluble mixed-ligand nickel(II) complexes of the type [NiL(1-4)(diimine)H2O]·(ClO4)2, (1-8) where L(1-4) = 2-((2-(piperazin-1-yl)ethylimino)methyl)-4-substituted phenols, and diimine = 2,2'-bipyridyl (bpy) or 1,10-phenanthroline (phen) were synthesized and characterized by elemental analysis and spectroscopic methods. The uncoordinated perchlorate anions was ascertained form IR spectra of the complexes, and the absorption spectra reveal the octahedron geometry around nickel(II) ion with tridentate Schiff base ligand, diimine and a coordinated water molecule. Cyclic voltammograms of the complexes indicate the one-electron irreversible processes in the cathodic and anodic region. In vitro antioxidant activity proved the significant radical scavenging activity of the complexes against DPPH radical. The groove/electrostatic binding nature of complexes with CT-DNA (calf thymus deoxyribonucleic acid) were affirmed by absorption, hydrodynamic and voltammetric titration experiments and docking analysis. All the complexes exhibit significant cleavage activity on plasmid DNA via hydrolytic and oxidatively, in which the oxidative mechanism involves hydroxyl radicals and supports the possibility of minor-groove binding. The complex 4 shows significant topoisomerase I (Topo-I) inhibitory activity. The molecular modeling analysis of complexes with phosphatidylinositol-3-kinase (PI3K) receptor indicate the hydrogen bonding with Met1039, Asp837 and Leu1027, and hydrophobic interactions with Ser488, Asn498, Asp500, Gln662, Lys668, Ile844, Ile847, Ile850, Val941, Leu942, Leu1020, Met1034, Leu1035, Thr1037, Met1039, Gln1041 and Ile1051 of subdomain IIA of BSA. The complexes show σ-π interaction between diimines and amino groups of Leu1030 and Arg839. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  6. Effect of mixed ligand complex therapy on the retention of 95Nb and 144Ce in mice

    SciTech Connect

    Gachalyi, A.; Namenyi, J.; Szegedi, I.; Varga, P.L. )

    1989-10-01

    We have examined in mice the effects of mixed ligand treatments with desferrioxamine B (DFOA), Na3Ca-diethylenetriamine pentaacetic acid (DTPA), and DL-penicillamine (PA) on the retention of a mixture of 95Nb and 144Ce. The results show that 95Nb + 144Ce could be mobilized effectively by simultaneous application of specific agents (i.e., DFOA, DTPA) with no decrease in their efficiencies.

  7. Complexity.

    PubMed

    Gómez-Hernández, J Jaime

    2006-01-01

    It is difficult to define complexity in modeling. Complexity is often associated with uncertainty since modeling uncertainty is an intrinsically difficult task. However, modeling uncertainty does not require, necessarily, complex models, in the sense of a model requiring an unmanageable number of degrees of freedom to characterize the aquifer. The relationship between complexity, uncertainty, heterogeneity, and stochastic modeling is not simple. Aquifer models should be able to quantify the uncertainty of their predictions, which can be done using stochastic models that produce heterogeneous realizations of aquifer parameters. This is the type of complexity addressed in this article.

  8. A cure for murine sickle cell disease through stable mixed chimerism and tolerance induction after nonmyeloablative conditioning and major histocompatibility complex-mismatched bone marrow transplantation.

    PubMed

    Kean, Leslie S; Durham, Megan M; Adams, Andrew B; Hsu, Lewis L; Perry, Jennifer R; Dillehay, Dirck; Pearson, Thomas C; Waller, Edmund K; Larsen, Christian P; Archer, David R

    2002-03-01

    The morbidity and mortality associated with sickle cell disease (SCD) is caused by hemolytic anemia, vaso-occlusion, and progressive multiorgan damage. Bone marrow transplantation (BMT) is currently the only curative therapy; however, toxic myeloablative preconditioning and barriers to allotransplantation limit this therapy to children with major SCD complications and HLA-matched donors. In trials of myeloablative BMT designed to yield total marrow replacement with donor stem cells, a subset of patients developed mixed chimerism. Importantly, these patients showed resolution of SCD complications. This implies that less toxic preparative regimens, purposefully yielding mixed chimerism after transplantation, may be sufficient to cure SCD without the risks of myeloablation. To rigorously test this hypothesis, we used a murine model for SCD to investigate whether nonmyeloablative preconditioning coupled with tolerance induction could intentionally create mixed chimerism and a clinical cure. We applied a well-tolerated, nonirradiation-based, allogeneic transplantation protocol using nonmyeloablative preconditioning (low-dose busulfan) and costimulation blockade (CTLA4-Ig and anti-CD40L) to produce mixed chimerism and transplantation tolerance to fully major histocompatibility complex-mismatched donor marrow. Chimeric mice were phenotypically cured of SCD and had normal RBC morphology and hematologic indices (hemoglobin, hematocrit, reticulocyte, and white blood cell counts) without evidence of graft versus host disease. Importantly, they also showed normalization of characteristic spleen and kidney pathology. These experiments demonstrate the ability to produce a phenotypic cure for murine SCD using a nonmyeloablative protocol with fully histocompatibility complex-mismatched donors. They suggest a future treatment strategy for human SCD patients that reduces the toxicity of conventional BMT and expands the use of allotransplantation to non-HLA-matched donors.

  9. X-ray diffraction and absorption spectroscopic studies of copper mixed ligand complexes with aminophenol as one of the ligands

    NASA Astrophysics Data System (ADS)

    Mishra, A.; Jain, Garima; Patil, H.

    2012-05-01

    X-ray diffraction (XRD) and X-ray absorption spectroscopic (XAS) studies have been conducted on two copper complexes, i.e., copper macrocyclic complex of succinic acid and ortho aminophenol (complex-1) and copper macrocyclic complex of pthalic acid and ortho aminophenol (complex-2). The diffraction pattern of the complexes have been recorded using Rigaku RINT-2000 X-ray diffractometer equipped with rotating anode X-ray tube operated at 40 kV and 100 mA. The X-ray absorption spectra of the complexes have been recorded at the K-edge of copper on Cauchois type bent crystal spectrograph having radius 0.4 m employing a mica crystal, oriented to reflect from (100) planes, for dispersion. The X-ray absorption near edge structure (XANES) parameters, viz., chemical shift, energy position of the principal absorption maximum and edge-width have been determined and discussed. From the extended X-ray absorption fine structure (EXAFS) data, the bond lengths have been calculated using three methods, namely, Levy's method, Lytle, Sayers and Stern's (LSS) method and Fourier transformation method. The results obtained have been compared with each other and discussed.

  10. Neutral-Type One-Dimensional Mixed-Valence Halogen-Bridged Platinum Chain Complexes with Large Charge-Transfer Band Gaps.

    PubMed

    Otake, Ken-ichi; Otsubo, Kazuya; Sugimoto, Kunihisa; Fujiwara, Akihiko; Kitagawa, Hiroshi

    2016-03-07

    One-dimensional (1D) electronic systems have attracted significant attention for a long time because of their various physical properties. Among 1D electronic systems, 1D halogen-bridged mixed-valence transition-metal complexes (the so-called MX chains) have been thoroughly studied owing to designable structures and electronic states. Here, we report the syntheses, structures, and electronic properties of three kinds of novel neutral MX-chain complexes. The crystal structures consist of 1D chains of Pt-X repeating units with (1R,2R)-(-)-diaminocychlohexane and CN(-) in-plane ligands. Because of the absence of a counteranion, the neutral MX chains have short interchain distances, so that strong interchain electronic interaction is expected. Resonance Raman spectra and diffuse-reflectance UV-vis spectra indicate that their electronic states are mixed-valence states (charge-density-wave state: Pt(2+)···X-Pt(4+)-X···Pt(2+)···X-Pt(4+)-X···). In addition, the relationship between the intervalence charge-transfer (IVCT) band gap and the degree of distortion of the 1D chain shows that the neutral MX chains have a larger IVCT band gap than that of cationic MX-chain complexes. These results provide new insight into the physical and electronic properties of 1D chain compounds.

  11. Mixed-Mode Fracture and Fatigue Analysis of Cracked 3D Complex Structures using a 3D SGBEM-FEM Alternating Method

    NASA Astrophysics Data System (ADS)

    Bhavanam, Sharada

    The aim of this thesis is to numerically evaluate the mixed-mode Stress Intensity Factors (SIFs) of complex 3D structural geometries with arbitrary 3D cracks using the Symmetric Galerkin Boundary Element Method-Finite Element Method (SGBEM-FEM) Alternating Method. Various structural geometries with different loading scenarios and crack configurations were examined in this thesis to understand the behavior and trends of the mixed-mode SIFs as well as the fatigue life for these complex structural geometries. Although some 3D structures have empirical and numerical solutions that are readily available in the open literature, some do not; therefore this thesis presents the results of fracture and fatigue analyses of these 3D complex structures using the SGBEM-FEM Alternating Method to serve as reference for future studies. Furthermore, there are advantages of using the SGBEM-FEM Alternating Method compared to traditional FEM methods. For example, the fatigue-crack-growth and fatigue life can be better estimated for a structure because different fatigue models (i.e. Walker, Paris, and NASGRO) can be used within the same framework of the SGBEM-FEM Alternating Method. The FEM (un-cracked structure)/BEM(crack model) meshes are modeled independently, which speeds up the computation process and reduces the cost of human labor. A simple coarse mesh can be used for all fracture and fatigue analyses of complex structures. In this thesis, simple coarse meshes were used for 3D complex structures, which were below 5000 elements as compared to traditional FEM, which require meshes where the elements range on the order of ˜250,000 to ˜106 and sometimes even more than that.

  12. Mixed metal copper(II)-nickel(II) and copper(II)-zinc(II) complexes of multihistidine peptide fragments of human prion protein.

    PubMed

    Jószai, Viktória; Turi, Ildikó; Kállay, Csilla; Pappalardo, Giuseppe; Di Natale, Giuseppe; Rizzarelli, Enrico; Sóvágó, Imre

    2012-07-01

    Mixed metal copper(II)-nickel(II) and copper(II)-zinc(II) complexes of four peptide fragments of human prion protein have been studied by potentiometric, UV-vis and circular dichroism spectroscopic techniques. One peptide contained three histidyl residues: HuPrP(84-114) with H85 inside and H96, H111 outside the octarepeat domain. The other three peptides contained two histidyl residues; H96 and H111 for HuPrP(91-115) and HuPrP(84-114)H85A while HuPrP(84-114)H96A contained the histidyl residues at positions 85 and 111. It was found that both histidines of the latter peptides can simultaneously bind copper(II) and nickel(II) ions and dinuclear mixed metal complexes can exist in slightly alkaline solution. One molecule of the peptide with three histidyl residues can bind two copper(II) and one nickel(II) ions. H85 and H111 were identified as the major copper(II) and H96 as the preferred nickel(II) binding sites in mixed metal species. The studies on the zinc(II)-PrP peptide binary systems revealed that zinc(II) ions can coordinate to the 31-mer PrP peptide fragments in the form of macrochelates with two or three coordinated imidazol-nitrogens but the low stability of these complexes cannot prevent the hydrolysis of the metal ion in slightly alkaline solution. These data provide further support for the outstanding affinity of copper(II) ions towards the peptide fragments of prion protein but the binding of nickel(II) can significantly modify the distribution of copper(II) among the available metal binding sites.

  13. Structural, molecular orbital and optical characterizations of binuclear mixed ligand copper (II) complex of phthalate with N,N,N',N'-tetramethylethylenediamine and its applications.

    PubMed

    Taha, A; Farag, A A M; Ammar, A H; Ahmed, H M

    2014-09-15

    A new binuclear mixed ligand complex, [Cu2(Phth)(Me4en)2(H2O)2(NO3)2]·H2O (where, Phth=phthalate, and (Me4en)=N,N,N',N'tetramethylethylenediamine) was synthesized and characterized using analytical, spectral, magnetic, molar conductance, thermal gravimetric analysis (TGA), X-ray diffraction (XRD) and transmission electron microscope (TEM) measurements. The XRD data of Cu(II)-complex was analyzed on the basis of Williamson-Hall (W-H) and compared with TEM results. The results indicate that the complex is well crystalline and correspond to hexagonal crystal structure. Analysis of the absorption coefficient near the absorption edge reveals that the optical band gaps are indirect allowed transition with values of 1.17 and 1.78 eV. The d-d absorption bands of the complex (dissolved in various solvents) exhibit a color changes (solvatochromic). Specific and non-specific interactions of solvent molecules with the complex were investigated using Multiple Linear Regression Analysis (MLRA). Transient photocurrent characteristics of Cu(II)-complex/n-Si heterojunctions indicate that photocurrent under illumination increase with increasing of light intensity and explained by continuous distribution of traps. Structural parameters of the free ligands and their Cu(II)-complex were calculated on the basis of semi-empirical PM3 level and compared with the experimental data. The present copper (II) complex was screened for its antimicrobial activity against some Gram-positive and Gram-negative bacteria and fungus strain. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Structural, molecular orbital and optical characterizations of binuclear mixed ligand copper (II) complex of phthalate with N,N,N‧,N‧-tetramethylethylenediamine and its applications

    NASA Astrophysics Data System (ADS)

    Taha, A.; Farag, A. A. M.; Ammar, A. H.; Ahmed, H. M.

    2014-09-01

    A new binuclear mixed ligand complex, [Cu2(Phth)(Me4en)2(H2O)2(NO3)2]·H2O (where, Phth = phthalate, and (Me4en) = N,N,N‧,N‧tetramethylethylenediamine) was synthesized and characterized using analytical, spectral, magnetic, molar conductance, thermal gravimetric analysis (TGA), X-ray diffraction (XRD) and transmission electron microscope (TEM) measurements. The XRD data of Cu(II)-complex was analyzed on the basis of Williamson-Hall (W-H) and compared with TEM results. The results indicate that the complex is well crystalline and correspond to hexagonal crystal structure. Analysis of the absorption coefficient near the absorption edge reveals that the optical band gaps are indirect allowed transition with values of 1.17 and 1.78 eV. The d-d absorption bands of the complex (dissolved in various solvents) exhibit a color changes (solvatochromic). Specific and non-specific interactions of solvent molecules with the complex were investigated using Multiple Linear Regression Analysis (MLRA). Transient photocurrent characteristics of Cu(II)-complex/n-Si heterojunctions indicate that photocurrent under illumination increase with increasing of light intensity and explained by continuous distribution of traps. Structural parameters of the free ligands and their Cu(II) - complex were calculated on the basis of semi-empirical PM3 level and compared with the experimental data. The present copper (II) complex was screened for its antimicrobial activity against some Gram-positive and Gram-negative bacteria and fungus strain.

  15. Highly luminescent mixed-metal Pt(II)/Ir(III) complexes: bis-cyclometalation of 4,6-diphenylpyrimidine as a versatile route to rigid multimetallic assemblies.

    PubMed

    Kozhevnikov, Valery N; Durrant, Marcus C; Williams, J A Gareth

    2011-07-04

    The proligand 4,6-di-(4-tert-butylphenyl)pyrimidine LH(2) can undergo cycloplatination with K(2)PtCl(4) at one of the two aryl rings to give, after treatment with sodium acetylacetonate, a mononuclear complex Pt(N^C-LH)(acac) (denoted Pt). If an excess of K(2)PtCl(4) is used, a dinuclear complex of the form [Pt(acac)](2){μ-(N^C-L-N^C)} (Pt(2)) is obtained instead, where the pyrimidine ring acts as a bridging unit. Alternatively, the mononuclear complex can undergo cyclometalation with a different metal ion. Thus, reaction of Pt with IrCl(3)·3H(2)O (2:1 ratio) leads, after treatment with sodium acetylacetonate, to an unprecedented mixed-metal complex of the form Ir{μ-(N^C-L-N^C)Pt(acac)}(2)(acac) (Pt(2)Ir). The mononuclear iridium complex Ir(N^C-LH)(2)(acac) (Ir) has also been prepared for comparison. The UV-visible absorption and photoluminesence properties of the four complexes and of the proligand have been investigated. The complexes are all highly luminescent, with quantum yields of around 0.5 in solution at room temperature. The introduction of the additional metal centers is found to lead to a substantial red-shift in absorption and emission, with λ(max) in the order Pt < Pt(2) < Ir < Pt(2)Ir. The trend is interpreted with the aid of electrochemical data and density functional theory calculations, which suggest that the red-shift is due primarily to a progressive stabilization of the lowest unoccupied molecular orbital (LUMO). The radiative decay constant is also increased. This versatile design strategy may offer a new approach for tuning and optimizing the luminescence properties of d-block metal complexes for contemporary applications. © 2011 American Chemical Society

  16. Unusual mixed valent FeIIIFeII complex (St = 3/2) stabilised by a reduced bulky 1,2-diketone.

    PubMed

    Spikes, Geoffrey H; Bill, Eckhard; Weyhermüller, Thomas; Wieghardt, Karl

    2007-11-14

    The reduction of the bulky 1,2-diketone bis(2,6-diisopropylphenyl)glyoxal () and FeBr(2) with 1.5 equivalents of Na results in a Class 2 mixed valent H.S. Fe(II) L.S. Fe(III) complex (2) with two five-coordinate Fe centres which are antiferromagnetically exchange-coupled to give a total spin S(t) = 3/2 ground state and an S(t) = 5/2 excited state that are separated by about 25 cm(-1) (for Delta(J) approximately 5J).

  17. Reactivity of tris(acetylacetonato) iron(III) with tridentate [ONO] donor Schiff base as an access to newer mixed-ligand iron(III) complexes

    NASA Astrophysics Data System (ADS)

    Bhattacharjee, Chira R.; Goswami, Pankaj; Pramanik, Harun A. R.; Paul, Pradip C.; Mondal, Paritosh

    2011-05-01

    Two new mixed-ligand iron(III) complexes, [Fe(L n)(acac)(C 2H 5OH)] incorporating coordinated ethanol from the reaction solvent were accessed from the reaction of [Fe(acac) 3] with [ONO] donor dibasic tridentate unsymmetrical Schiff base ligands derived from condensation of 2-hydroxy-1-napthaldehyde with 2-aminophenol (H 2L 1) or 2-aminobenzoic acid (H 2L 2). The thermal study (TGA-DTA) provided evidence for weakly bound ethanol which is readily substituted by neutral N-donor molecule imidazole, benzimidazole or pyridine to produce an array of newer complexes, [Fe(L n)(acac)X] ( n = 1, 2; X = Im, Bim, Py). The compounds were characterized by elemental analyses, FT-IR, UV-vis, solution electrical conductivity, FAB mass, 1H and 13C NMR spectroscopy. Room temperature magnetic susceptibility measurements ( μeff ˜ 5.8 B.M.) are consistent with spin-free octahedral iron(III) complexes. Cyclic voltammetry of ethanol complexes revealed a quasi-reversible one electron redox response (Δ Ep > 100 mV) for the Fe(III)/Fe(II) couple. Low half wave redox potential ( E1/2) values suggested easy redox susceptibility. The ground state geometries of the ethanol and imidazole complexes have been ascertained to be distorted octahedral by density functional theory using DMol3 program at BLYP/DNP level.

  18. Mixed ligand complexes of cobalt(III) and iron(III) containing N2O2-chelating Schiff base: Synthesis, characterisation, antimicrobial activity, antioxidant and DFT study

    NASA Astrophysics Data System (ADS)

    Pramanik, Harun A. R.; Paul, Pradip C.; Mondal, Paritosh; Bhattacharjee, Chira R.

    2015-11-01

    Six mixed ligand complexes, namely, [Co(acac)L1] (1), [Fe(acac)L1] (2), [Co(acac)L2] (3), [Fe(acac)L2] (4), [Co(acac)L3] (5), and [Fe(acac)L3] (6) (H2L1 = NN/-bis(salicylidene)-trans 1,2 diaminocyclohexane, H2L2 = NN/-bis(salicylidene)-1,2 phenylenediamine, H2L3 = NN/-bis(salicylidene)-4-methyl-1,2-phenylenediamine) were synthesised and characterized using elemental analysis, IR spectra, UV-Vis spectra, mass spectra, magnetic susceptibility measurements, 1H and 13C NMR spectroscopy, thermogravimetric analysis. The molar conductance measurement confirmed the non-electrolytic nature of the complexes in DMF solution. Antioxidant activity of the complexes was studied using the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) scavenging method. Biological studies of the complexes have been carried out in vitro for antimicrobial activity against some selected gram-positive and gram-negative bacteria. DFT calculations were performed using GAUSSIAN 09 program to ascertain the stable electronic structure, HOMO-LUMO energy gap, chemical hardness and dipole moment of the complexes.

  19. Synthesis, characterization, and activity of yttrium(III) nitrate complexes bearing tripodal phosphine oxide and mixed phosphine-phosphine oxide ligands.

    PubMed

    Sues, Peter E; Lough, Alan J; Morris, Robert H

    2012-09-03

    A series of four tripodal phosphine oxide ligands, (OPR(2))(2)CHCH(2)POR(2) (1a-1d), and four mixed phosphine-phosphine oxide ligands, (OPR(2))(2)CHCH(2)PR(2) (3a-3d), were synthesized and coordinated to yttrium to produce Y(NO(3))(3)[(OPR(2))(2)CHCH(2)POR(2)] (2a-2d) and Y(NO(3))(3)[(OPR(2))(2)CHCH(2)PR(2)](OPPh(3)) (4a-4d) complexes. The previously reported ligand 1a and unknown phosphine oxide ligands 1b-1d were generated in an unprecedented trisubstitution reaction of bromoacetaldehyde diethyl acetal, while the novel partially reduced ligands 3a-3d were synthesized from 1a-1d according to a known literature protocol for the selective monoreduction of bisphosphine oxides. The neutral yttrium complexes 2a-2d are nine-coordinate and display a tricapped trigonal-prismatic geometry. Complexes 4a-4d are also neutral, nine-coordinate species and have a pendant phosphine functionality, which provides the potential to form bimetallic early-late transition-metal complexes. Additionally, yttrium complexes 2a-2d were activated with base and tested for the ring-opening polymerization of ε-caprolactone, but the results showed that base by itself was significantly more effective than the yttrium species investigated.

  20. Luminescent dinuclear copper(I) complexes bearing 1,4-bis(diphenylphosphino)butane and functionalized 3-(2'-pyridyl)pyrazole mixed ligands.

    PubMed

    Chen, Jing-Lin; Guo, Zong-Hao; Yu, Hua-Guang; He, Li-Hua; Liu, Sui-Jun; Wen, He-Rui; Wang, Jin-Yun

    2016-01-14

    A family of new dinuclear Cu(i) complexes with 1,4-bis(diphenylphosphino)butane (dppb) and functionalized 3-(2'-pyridyl)pyrazole mixed ligands has been synthesized and characterized. It is revealed that all these Cu(i) complexes include a [Cu2(dppb)2](2+) framework with the two Cu(i) atoms doubly bridged by a pair of dppb to generate a fourteen-membered Cu2P4C8 ring, and functionalized 3-(2'-pyridyl)pyrazole adopts a neutral chelating coordination mode without the N-H bond cleavage of the pyrazolyl ring. All these dinuclear Cu(i) complexes display a relatively weak low-energy absorption in CH2Cl2 solution, which is closely related to the variation of the Cu-N and Cu-P bonds caused by the substituent on the pyrazolyl ring. These dinuclear Cu(i) complexes are all emissive in solution and solid states at ambient temperature, which can be well modulated through structural modification of 3-(2'-pyridyl)pyrazole. It is shown that introduction of the trifluoromethyl group into the pyrazolyl ring is helpful for enhancing the luminescence properties of Cu(i) pyrazole phosphine complexes.

  1. Mixed Ligand Complexes of N-Methyl-N-phenyl Dithiocarbamate: Synthesis, Characterisation, Antifungal Activity, and Solvent Extraction Studies of the Ligand

    PubMed Central

    Ekennia, Anthony C.; Onwudiwe, Damian C.; Ume, Cyril; Ebenso, Eno E.

    2015-01-01

    A series of mixed ligand dithiocarbamate complexes with a general formula [ML2(py)2], where M = Mn(II), Co(II), Ni(II), and Cu(II), py = pyridine, and L = N-methyl-N-phenyl dithiocarbamate have been prepared and characterised by elemental analysis, FTIR and Uv spectroscopy, magnetic moment, and thermogravimetric and conductance analysis. The infrared spectra showed that symmetrical bidentate coordination occurred with the dithiocarbamate moiety through the sulfur atoms, while neutral monodentate coordination occurred through the nitrogen atom for the pyridine molecule in the complexes. The electronic spectra, elemental analysis, and magnetic moment results proved that the complexes adopted octahedral geometry. The conductance measurement showed that the complexes are nonelectrolytes proving their nonionic nature. The compounds were screened for three human pathogenic fungi: Aspergillus flavus, Aspergillus niger, and Candida albicans. The cobalt complex showed the best antifungal activity among the test compounds. Liquid-liquid extractive abilities of the ligand towards copper and nickel ions in different solvent media were investigated. The ligand showed a strong binding affinity towards the metals ions with an extractive efficiency of about 99%. PMID:26543441

  2. Complexities in Isolation and Purification of Multiple Viruses from Mixed Viral Infections: Viral Interference, Persistence and Exclusion.

    PubMed

    Kumar, Naveen; Barua, Sanjay; Riyesh, Thachamvally; Chaubey, Kundan K; Rawat, Krishan Dutt; Khandelwal, Nitin; Mishra, Anil K; Sharma, Nitika; Chandel, Surender S; Sharma, Shalini; Singh, Manoj K; Sharma, Dinesh K; Singh, Shoor V; Tripathi, Bhupendra N

    2016-01-01

    Successful purification of multiple viruses from mixed infections remains a challenge. In this study, we investigated peste des petits ruminants virus (PPRV) and foot-and-mouth disease virus (FMDV) mixed infection in goats. Rather than in a single cell type, cytopathic effect (CPE) of the virus was observed in cocultured Vero/BHK-21 cells at 6th blind passage (BP). PPRV, but not FMDV could be purified from the virus mixture by plaque assay. Viral RNA (mixture) transfection in BHK-21 cells produced FMDV but not PPRV virions, a strategy which we have successfully employed for the first time to eliminate the negative-stranded RNA virus from the virus mixture. FMDV phenotypes, such as replication competent but noncytolytic, cytolytic but defective in plaque formation and, cytolytic but defective in both plaque formation and standard FMDV genome were observed respectively, at passage level BP8, BP15 and BP19 and hence complicated virus isolation in the cell culture system. Mixed infection was not found to induce any significant antigenic and genetic diversity in both PPRV and FMDV. Further, we for the first time demonstrated the viral interference between PPRV and FMDV. Prior transfection of PPRV RNA, but not Newcastle disease virus (NDV) and rotavirus RNA resulted in reduced FMDV replication in BHK-21 cells suggesting that the PPRV RNA-induced interference was specifically directed against FMDV. On long-term coinfection of some acute pathogenic viruses (all possible combinations of PPRV, FMDV, NDV and buffalopox virus) in Vero cells, in most cases, one of the coinfecting viruses was excluded at passage level 5 suggesting that the long-term coinfection may modify viral persistence. To the best of our knowledge, this is the first documented evidence describing a natural mixed infection of FMDV and PPRV. The study not only provides simple and reliable methodologies for isolation and purification of two epidemiologically and economically important groups of viruses, but

  3. An Application of the Multivariate Linear Mixed Model to the Analysis of Shoulder Complexity in Breast Cancer Patients.

    PubMed

    Oskrochi, Gholamreza; Lesaffre, Emmanuel; Oskrochi, Youssof; Shamley, Delva

    2016-03-02

    In this study, four major muscles acting on the scapula were investigated in patients who had been treated in the last six years for unilateral carcinoma of the breast. Muscle activity was assessed by electromyography during abduction and adduction of the affected and unaffected arms. The main principal aim of the study was to compare shoulder muscle activity in the affected and unaffected shoulder during elevation of the arm. A multivariate linear mixed model was introduced and applied to address the principal aims. The result of fitting this model to the data shows a huge improvement as compared to the alternatives.

  4. Complexities in Isolation and Purification of Multiple Viruses from Mixed Viral Infections: Viral Interference, Persistence and Exclusion

    PubMed Central

    Kumar, Naveen; Barua, Sanjay; Riyesh, Thachamvally; Chaubey, Kundan K.; Rawat, Krishan Dutt; Khandelwal, Nitin; Mishra, Anil K.; Sharma, Nitika; Chandel, Surender S.; Sharma, Shalini; Singh, Manoj K.; Sharma, Dinesh K.; Singh, Shoor V.; Tripathi, Bhupendra N.

    2016-01-01

    Successful purification of multiple viruses from mixed infections remains a challenge. In this study, we investigated peste des petits ruminants virus (PPRV) and foot-and-mouth disease virus (FMDV) mixed infection in goats. Rather than in a single cell type, cytopathic effect (CPE) of the virus was observed in cocultured Vero/BHK-21 cells at 6th blind passage (BP). PPRV, but not FMDV could be purified from the virus mixture by plaque assay. Viral RNA (mixture) transfection in BHK-21 cells produced FMDV but not PPRV virions, a strategy which we have successfully employed for the first time to eliminate the negative-stranded RNA virus from the virus mixture. FMDV phenotypes, such as replication competent but noncytolytic, cytolytic but defective in plaque formation and, cytolytic but defective in both plaque formation and standard FMDV genome were observed respectively, at passage level BP8, BP15 and BP19 and hence complicated virus isolation in the cell culture system. Mixed infection was not found to induce any significant antigenic and genetic diversity in both PPRV and FMDV. Further, we for the first time demonstrated the viral interference between PPRV and FMDV. Prior transfection of PPRV RNA, but not Newcastle disease virus (NDV) and rotavirus RNA resulted in reduced FMDV replication in BHK-21 cells suggesting that the PPRV RNA-induced interference was specifically directed against FMDV. On long-term coinfection of some acute pathogenic viruses (all possible combinations of PPRV, FMDV, NDV and buffalopox virus) in Vero cells, in most cases, one of the coinfecting viruses was excluded at passage level 5 suggesting that the long-term coinfection may modify viral persistence. To the best of our knowledge, this is the first documented evidence describing a natural mixed infection of FMDV and PPRV. The study not only provides simple and reliable methodologies for isolation and purification of two epidemiologically and economically important groups of viruses, but

  5. [Dimensional characteristics and spatial distribution patterns of pit and mound complexes in Pinus koraiensis-dominated broadleaved mixed forest].

    PubMed

    Duan, Wen-Biao; Wei, Quan-Shuai; Qiao, Lu; Chen, Li-Xin; Wang, Ting; Zhang, Xin; Gu, Wei; Sun, Hu

    2014-11-01

    Characteristics of pit and mound complexes in different sizes of forest gaps and closed stands and their distribution patterns were compared and analyzed. The results showed that mean mound width, mound height, mound thickness of all pit and mound complexes were larger than corresponding mean pit length, pit width, pit depth in large, medium and small gaps as well as in closed stands. Mound width, mound height, mound thickness, pit length, pit width, pit depth were the largest in large gap, being 2.85, 0.37, 2.00, 2.99, 2.10, 0.39 m, respectively, and the smallest in closed stands, being 2.35, 0.19, 1.60, 2.66, 1.65, 0.21, respectively. Mean mound volume (1.66 m3) was larger than mean pit volume (1.44 m3). The difference in characteristic values between the most of pit and mound complexes was significant for the same size of forest gap, not significant for closed stands, significant for different sizes of forest gaps and closed stands. Most of characteristic values for pit and mound complexes within the plot in 2012 were significantly less than those in 2011. 89.5% and 60.5% of type and shape of pit and mound complexes were hinge and semiellipse, respectively. Their distribution was relatively centralized.

  6. Crystal structure and EPR studies of mixed ligand complex of cobalt(II) with saccharin and ethylisonicotine

    NASA Astrophysics Data System (ADS)

    Uçar, İbrahim; Karabulut, Bünyamin; Bulut, Ahmet; Büyükgüngör, Orhan

    2008-12-01

    The tetraaquabis(ethylisonicotinate)cobalt(II) disaccharinate, [Co(ein) 2(H 2O) 4]·(sac) 2, (CENS), (ein: ethylisonicotinate and sac: saccharinate) complex has been synthesized and its crystal structure has been determined by X-ray diffraction analysis. The title complex crystallizes in monoclinic system with space group P2 1/ c and Z = 2. The Co(II) cations present a slightly distorted CoN 2O 4 octahedral environment, with equatorially coordinated water molecules and axially pyridine N-bound ethylisonicotinate ligands. The magnetic environments of Cu 2+-doped Co(II) complex have been identified by electron paramagnetic resonance (EPR) technique. Cu 2+-doped CENS single crystals have been studied at room temperature in three mutually perpendicular planes. The calculated results of the Cu 2+-doped CENS indicate that Cu 2+ ion substitute with the Co 2+ ion in the host lattice. The angular variations of the EPR spectra have shown that two different Cu 2+ complexes are located in different chemical environments, and each environment contains two magnetically inequvalent Cu 2+sites in distinct orientations occupying substitutional positions in the lattice and show very high angular dependence. The cyclic voltammogram of the title complex investigated in dimethylformamide (DMF) solution exhibits only metal centerd electroactivity in the potential range -1.0-1.25 V versus Ag/AgCl reference electrode.

  7. Novel mixed ligand di-n-butyltin(IV) complexes derived from acylpyrazolones and fluorinated benzoic acids: synthesis, characterization, cytotoxicity and the induction of apoptosis in Hela cancer cells.

    PubMed

    Zhao, Bin; Shang, Xianmei; Xu, Ling; Zhang, Wendian; Xiang, Guangya

    2014-04-09

    Twenty one novel mixed ligand di-n-butyltin(IV) complexes [(n)Bu2SnAL] (A = substituted 4-acyl-5-pyrazolone, and L = fluorinated benzoic acid) were prepared by condensation of di-n-butyltin(IV) oxide with HL and HA in 1:1:1 molar ratio in refluxing methanol. All of the complexes were characterized by elemental analyses, IR, NMR ((1)H, (13)C, (119)Sn) and in four cases by X-ray diffraction. Cytotoxicity of the compounds was studied against two human cancer cell lines (KB and Hela) by means of the MTT assay compared to cisplatin, featuring IC₅₀ values in the low micromolar range. Hela cancer cell apoptosis-induced by 2 was examined by flow cytometry analysis, and preliminary results showed that 2 at concentrations of more than 1.0 μM can induce apoptosis.

  8. Electrochemical-driven hydrogen evolution from acetic acid and water catalyzed by a mixed-valent CoII-CoI complex with high turnover frequency

    NASA Astrophysics Data System (ADS)

    Cao, Jie-Ping; Fu, Ling-Zhi; Zhou, Ling-Ling; Zhan, Shu-Zhong

    2015-04-01

    The reaction of 2,3-bis(2-hydroxybenzylideneimino)-2,3-butenedinitrile (H2L1) and CoCl2·6H2O affords a mixed-valent dinuclear CoII-CoI complex [CoIL(py)3][CoIIL2] 1 (L = 2-(2-hydroxybenzylideneimino)-butenedinitrile ion), a new molecular electrocatalyst, which has been determined by X-ray crystallography and XPS spectrum. Electrochemical studies indicate that the catalyst is the first CoII-CoI complex species, that is among the most rapid homogeneous water-reduction catalysts, with a turnover frequency (TOF) of 2387 mol of hydrogen per mole of catalyst per hour at an overpotential of 787 mV vs SHE (pH 7.0). Sustained proton reduction catalysis occurs at glassy carbon (GC) to give H2 over a 46 h electrolysis period with 97% Faradaic yield and no observable decomposition of the catalyst.

  9. Effects of structural complexity on within-canopy light environments and leaf traits in a northern mixed deciduous forest

    NASA Astrophysics Data System (ADS)

    Fotis, A. T.; Curtis, P.

    2016-12-01

    Canopy structure influences forest productivity through its effects on the distribution of radiation and the light-induced changes in leaf physiological traits. Due to the difficulty of accessing and measuring forest canopies, few field-based studies have quantitatively linked these divergent scales of canopy functioning. The objective of our study was to investigate how canopy structure affects light profiles within a forest canopy and whether leaves of mature trees adjust morphologically and biochemically to the light environments characteristic of canopies with different structural complexity. We used a combination of light detection and ranging (LiDAR) data and hemispherical photographs to quantify canopy structure and light environments, respectively, and a telescoping pole to sample leaves. Leaf mass per area (LMA), nitrogen on an area basis (Narea) and chlorophyll on a mass basis (Chlmass) were measured in four co-dominant species (Acer rubrum, Fagus grandifolia, Pinus strobus and Quercus rubra) at different heights in plots with similar leaf area index (LAI) but contrasting canopy complexity (rugosity). We found that more complex canopies had greater porosity and reduced light variability in the midcanopy while total light interception was unchanged relative to less complex canopies. Leaves of F. grandifolia, Q. rubra, and P. strobus shifted towards sun-acclimation phenotypes with increasing canopy complexity while leaves of A. rubrum became more shade-acclimated (lower LMA) in the upper canopy of more complex stands, despite no differences in total light interception. Broadleaf species showed further acclimation by increasing Narea and reducing Chlmass as LMA increased, while P. strobus showed no change in Narea and Chlmass with increasing LMA. Our results provide new insight on how light distribution and leaf acclimation in mature trees might be altered when natural and anthropogenic disturbances cause structural changes in the canopy.

  10. Effects of structural complexity on within-canopy light environments and leaf traits in a northern mixed deciduous forest.

    PubMed

    Fotis, Alexander T; Curtis, Peter S

    2017-01-18

    Canopy structure influences forest productivity through its effects on the distribution of radiation and the light-induced changes in leaf physiological traits. Due to the difficulty of accessing and measuring forest canopies, few field-based studies have quantitatively linked these divergent scales of canopy functioning. The objective of our study was to investigate how canopy structure affects light profiles within a forest canopy and whether leaves of mature trees adjust morphologically and biochemically to the light environments characteristic of canopies with different structural complexity. We used a combination of light detection and ranging (LiDAR) data and hemispherical photographs to quantify canopy structure and light environments, respectively, and a telescoping pole to sample leaves. Leaf mass per area (LMA), nitrogen on an area basis (Narea) and chlorophyll on a mass basis (Chlmass) were measured in red maple (Acer rubrum), american beech (Fagus grandifolia), white pine (Pinus strobus), and northern red oak (Quercus rubra) at different heights in plots with similar leaf area index but contrasting canopy complexity (rugosity). We found that more complex canopies had greater porosity and reduced light variability in the midcanopy while total light interception was unchanged relative to less complex canopies. Leaf phenotypes of F. grandifolia, Q. rubra and P strobus were more sun-acclimated in the midstory of structurally complex canopies while leaf phenotypes of A. rubrum were more shade-acclimated (lower LMA) in the upper canopy of more complex stands, despite no differences in total light interception. Broadleaf species showed further differences in acclimation with increased Narea and reduced Chlmass in leaves with higher LMA, while P. strobus showed no change in Narea and Chlmass with higher LMA. Our results provide new insight on how light distribution and leaf acclimation in mature trees might be altered when natural and anthropogenic disturbances

  11. Preparation, characterization and cytotoxicity studies of some transition metal complexes with ofloxacin and 1,10-phenanthroline mixed ligand

    NASA Astrophysics Data System (ADS)

    Sadeek, S. A.; El-Hamid, S. M. Abd

    2016-10-01

    [Zn(Ofl)(Phen)(H2O)2](CH3COO)·2H2O (1), [ZrO(Ofl)(Phen)(H2O)]NO3·2H2O (2) and [UO2(Ofl)(Phen)(H2O)](CH3COO)·H2O (3) complexes of fluoroquinolone antibacterial agent ofloxacin (HOfl), containing a nitrogen donor heterocyclic ligand, 1,10-phenathroline monohydrate (Phen), were prepared and their structures were established with the help of elemental analysis, molar conductance, magnetic properties, thermal studies and different spectroscopic studies like IR, UV-Vis., 1H NMR and Mass. The IR data of HOfl and Phen ligands suggested the existing of a bidentate binding involving carboxylate O and pyridone O for HOfl ligand and two pyridine N atoms for Phen ligand. The coordination geometries and electronic structures are determined from electronic absorption spectra and magnetic moment measurements. From molar conductance studies reveals that metal complexes are electrolytes and of 1:1 type. The calculated bond length and force constant, F(Udbnd O), in the uranyl complex are 1.751 Å and 641.04 Nm-1. The thermal properties of the complexes were investigated by thermogravimetry (TGA) technique. The activation thermodynamic parameters are calculated using Coats-Redfern and Horowitz-Metzger methods. Antimicrobial activity of the compounds was evaluated against some bacteria and fungi species. The activity data show that most metal complexes have antibacterial activity than that of the parent HOfl drug. The in vitro cytotoxicities of ligands and their complexes were also evaluated against human breast and colon carcinoma cells.

  12. Toward Rational Design of Protein Detergent Complexes: Determinants of Mixed Micelles That Are Critical for the In Vitro Stabilization of a G-Protein Coupled Receptor

    PubMed Central

    O'Malley, Michelle A.; Helgeson, Matthew E.; Wagner, Norman J.; Robinson, Anne S.

    2011-01-01

    Although reconstitution of membrane proteins within protein detergent complexes is often used to enable their structural or biophysical characterization, it is unclear how one should rationally choose the appropriate micellar environment to preserve native protein folding. Here, we investigated model mixed micelles consisting of a nonionic glucosylated alkane surfactant from the maltoside and thiomaltoside families, bile salt surfactant, and the steryl derivative cholesteryl hemisuccinate. We correlated several key attributes of these micelles with the in vitro ligand-binding activity of hA2aR in these systems. Through small-angle neutron scattering and radioligand-binding analysis, we found several key aspects of mixed micellar systems that preserve the activity of hA2aR, including a critical amount of cholesteryl hemisuccinate per micelle, and an optimal hydrophobic thickness of the micelle that is analogous to the thickness of native mammalian bilayers. These features are closely linked to the headgroup chemistry of the surfactant and the hydrocarbon chain length, which influence both the morphology and composition of resulting micelles. This study should serve as a general guide for selecting the appropriate mixed surfactant systems to stabilize membrane proteins for biophysical analysis. PMID:22004748

  13. Infrared spectroscopic characteristics of mixed rare earth triple-decker complexes with phthalocyaninato and 5-(4-hydroxyphenyl)-10,15,20-tris(4-octyloxy)porphyrinato ligands.

    PubMed

    Wang, Wendong; Bao, Guihong; Mao, Yajun; Lu, Fanli

    2013-03-01

    The infrared (IR) spectroscopic data for a series of nine mixed rare earth triple-deckers M(2)(III)[TO(OH)PP](Pc)(2)] [M=La···Dy, except Pm, Y and Ho⋯Lu; H(2)Por=5-(4-hydroxyphenyl)-10,15,20-tris(4-octyloxyphenyl)porphyrin, Pc=unsubstituted phthalocyanine] with tervalent rare earths have been collected. For M(2)(III)[TO(OH)PP](Pc)(2)], typical IR marker bands for the unsubstituted phthalocyanine dianion Pc(2-) are strong bands at 1327-1329 cm(-1), and a weak band around 1370-1383 cm(-1). They can be assigned to pyrrole CC stretchings. The absence of Pc(2-) another marker IR band around 1376 cm(-1) demonstrates that the cerium metal ion in the IR spectrum of Ce(2)(III)[TO(OH)PP](Pc)(2)] exists as intermediate valence state between III and IV. The IR spectra of these mixed triple-decker complexes reveal that the frequencies of pyrrole stretching, isoindole breathing, and aza stretchings are decreased sensitive to the rare earth ionic size, and remain basically unchanged along with the lanthanide contraction. These facts indicate that the π-π interactions in these mixed triple-deckers are weaker than those in the double-deckers.

  14. Infrared spectroscopic characteristics of mixed rare earth triple-decker complexes with phthalocyaninato and 5-(4-hydroxyphenyl)-10,15,20-tris(4-octyloxy)porphyrinato ligands

    NASA Astrophysics Data System (ADS)

    Wang, Wendong; Bao, Guihong; Mao, Yajun; Lu, Fanli

    2013-03-01

    The infrared (IR) spectroscopic data for a series of nine mixed rare earth triple-deckers M2III[TO(OH)PP](Pc)2] [M = La⋯Dy, except Pm, Y and Ho⋯Lu; H2Por = 5-(4-hydroxyphenyl)-10,15,20-tris(4-octyloxyphenyl)porphyrin, Pc = unsubstituted phthalocyanine] with tervalent rare earths have been collected. For M2III[TO(OH)PP](Pc)2], typical IR marker bands for the unsubstituted phthalocyanine dianion Pc2- are strong bands at 1327-1329 cm-1, and a weak band around 1370-1383 cm-1. They can be assigned to pyrrole Cdbnd C stretchings. The absence of Pc2- another marker IR band around 1376 cm-1 demonstrates that the cerium metal ion in the IR spectrum of Ce2III[TO(OH)PP](Pc)2] exists as intermediate valence state between III and IV. The IR spectra of these mixed triple-decker complexes reveal that the frequencies of pyrrole stretching, isoindole breathing, and aza stretchings are decreased sensitive to the rare earth ionic size, and remain basically unchanged along with the lanthanide contraction. These facts indicate that the π-π interactions in these mixed triple-deckers are weaker than those in the double-deckers.

  15. Linkage effects to nonlinear optical properties of porphyrin-appended mixed (porphyrinato)(phthalocyaninato) yttrium(III) double-decker complexes

    NASA Astrophysics Data System (ADS)

    Li, Yong; Zhang, Xianyao; Yan, Xingzhong; Bian, Yongzhong; Jiang, Jianzhuang

    2011-10-01

    Third-order nonlinear optical properties of three isomeric tetrapyrrole triads, i.e. mixed (porphyrinato)(phthalocyaninato) yttrium double-decker complexes appended with one metal free porphyrin chromophore at the para, meta, and orthoposition, respectively, of one meso-phenyl group of the porphyrin ligand in the double-decker unit through ester linkage, 3-5, were comparatively investigated along with the model compounds metal free meso-tetrakis(4-tert-butylphenyl) porphyrin H2TBPP (1) and mixed [meso-tetrakis(4-tert-butylphenyl)porphyrinato] [1,4,8,11,15,18,22,25-octakis(butyloxyl)phthalocyaninato] yttrium double-decker complex YIIIH(TBPP) [Pc(α-OC4H9)8] (2) by using Z-scan technique with the fundamental (800 nm) laser emission from a Ti:sapphire femtosecond laser system. Strong reverse saturable absorption (RSA) properties of complexes 2-5 were observed. Interestingly, under highly intense irradiation, an RSA-SA-RSA-SA-RSA switch behavior was evolved in the tight focal intensity regime on the Z-scan profiles of complexes 3-5. Under the laser irradiation with focal intensity of 7.48-8.39 GW.cm-2, the triads 3 and 4 with the metal free porphyrin chromophore appended at the para or meta positions of the meso-phenyl group of the porphyrin ligand in the double-decker unit retained a characteristic response of RSA. In contrast, the triad 5 with the metal free porphyrin chromophore appended at the ortho position has already shown a trend of SA peaks at the same intensity range, revealing the effect of the position of porphyrin-substituent on the nonlinear optical properties of the triads.

  16. Oxidative DNA damage of mixed copper(II) complexes with sulfonamides and 1,10-phenanthroline. Crystal structure of [Cu(N-quinolin-8-yl-p-toluenesulfonamidate)2(1,10-phenanthroline)].

    PubMed

    Macías, Benigno; García, Isabel; Villa, María V; Borrás, Joaquín; González-Alvarez, Marta; Castiñeiras, Alfonso

    2003-08-01

    Mixed coordination compounds of Cu(II) with sulfonamides and 1,10-phenanthroline as ligands have been prepared and characterised. Single crystal structural determination of the complex [Cu(N-quinolin-8-yl-p-toluenesulfonamidate)(2)(phen)] shows Cu(II) ions are located in a highly distorted octahedral environment, probably as a consequence of the Jahn-Teller effect. The FT-IR and electronic paramagnetic resonance (EPR) spectra are also discussed. The mixed complexes prepared undergo an extensive DNA cleavage in the presence of ascorbate and hydrogen peroxide. Two of the complexes have higher nucleolytic efficiency than the bis(o-phenanthroline)copper(II) complex.

  17. New mixed ligand zinc(II) complexes based on the antiepileptic drug sodium valproate and bioactive nitrogen-donor ligands. Synthesis, structure and biological properties.

    PubMed

    Darawsheh, Mohanad; Abu Ali, Hijazi; Abuhijleh, A Latif; Rappocciolo, Emilia; Akkawi, Mutaz; Jaber, Suhair; Maloul, Salam; Hussein, Yasmeen

    2014-07-23

    Starting from the precursor [Zinc Valproate complex] (1), new mixed ligand zinc(II) complexes of valproic acid and nitrogen-based ligands, formulating as, [Zn(valp)22,9-dmphen] (2), [Zn2(valp)4(quin)2] (3), [Zn(valp)2(2-ampy)2] (4), and [Zn(valp)2(2-ampic)2] (5) (valp = valproate, 2,9-dmphen = 2,9-dimethyl-1,10-phenanthroline, quin = quinoline, 2-ampy = 2-aminopyridine, 2-ampic = 2-amino-6-picoline) were synthesized and characterized using IR, (1)H NMR, (13)C{(1)H} NMR and UV-Vis spectrometry. The crystal structures of complexes 2, 3 and 4 were determined using single-crystal X-ray diffraction. The complexes were also evaluated for their anti-bacterial activity using in-vitro agar diffusion method against three Gram-positive (Micrococcus luteus, Staphylococcus aureus, and Bacillus subtilis) and three Gram-negative (Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis) species. Complex 2 showed considerable activity against all tested microorganisms and the effect of complexation on the anti-bacterial activity of the parent ligand of 2 was also investigated. The anti-bacterial activity of 2,9-dmphen against Gram-negative bacteria was enhanced upon complexation with zinc valproate. On the other hand, complexes 1 and 3 showed weak inhibition activity against the tested species and complexes 4 and 5 didn't show any activity at all. Two methods were used for testing the inhibition of ferriprotoporphyrinIX bio-mineralization: a semi-quantitative micro-assay and a previously self-developed quantitative in-vitro method. Both were used to study the efficiency of these complexes in inhibiting the formation of the Malaria pigment which considered being the target of many known anti-malarial drugs such as Chloroquine and Amodiaquine. Results showed that the efficiency of complex 2 in preventing the formation of β-Hematin was 80%. The efficiency of Amodiaquine as a standard drug was reported to give 91%.

  18. Petrogenesis of alkaline magmas at Minna Bluff, Antarctica: evidence for multi-stage differentiation and complex mixing processes

    NASA Astrophysics Data System (ADS)

    Panter, K. S.; Dunbar, N. W.; Scanlan, M. K.; Wilch, T. I.; Fargo, A. J.; McIntosh, W. C.

    2011-12-01

    Minna Bluff, a 45-km-long peninsula that extends SE into the Ross Ice Shelf from the Mt. Discovery stratovolcano, consists of coalesced late Miocene volcanic centers formed through eruption of alkaline magma compositions in a continental rift setting. Highly silica-undersaturated compositions vary from basanite to phonolite and are exposed in volcanic features ranging from small, primitive, cinder cones to large, evolved domes. Lava compositions are more evolved on the eastern end of Minna Bluff and show an overall age progression to younger, more mafic compositions towards Mt. Discovery. Phenocrysts in lava include amphibole, plagioclase and alkali feldspar, pyroxene, olivine, magnetite and apatite. A notable feature of volcanic rocks at Minna Bluff is the presence of large (up to 5 cm) kaersutite and feldspar megacrysts and deposits that contain abundant comagmatic inclusions (kaersutite-rich) and rare mantle xenoliths. Many lavas exhibit strong disequilibrium textures, mainly expressed by breakdown rims on kaersutite that vary dramatically in thickness from crystal to crystal, but reverse compositional zoning in plagioclase is also common. Kaersutite compositions vary within a single sample and show the same compositional range and similar disequilibrium textures in rocks that vary significantly in bulk composition. The textural and compositional characteristics suggest that, for many, mixing between one or more magmas controlled the final composition of the magmas. We envisage a scenario by which some of the primitive, mantle-derived, fluid-rich magmas rose relatively unimpeded to erupt at the surface, while others stalled at or near the crust-mantle boundary and differentiated. Semi-quantitative thermobarometric results for kaersutite and clinopyroxene indicate maximum P-T-X conditions for crystallization of hydrous magmas at 5-9 kbar, ≧1000°C and ≈3 wt. % equiv. H2O. The P-T estimates closely match geophysical and petrologic geotherm estimates for Moho

  19. Organizational Agility and Complex Enterprise System Innovations: A Mixed Methods Study of the Effects of Enterprise Systems on Organizational Agility

    ERIC Educational Resources Information Center

    Kharabe, Amol T.

    2012-01-01

    Over the last two decades, firms have operated in "increasingly" accelerated "high-velocity" dynamic markets, which require them to become "agile." During the same time frame, firms have increasingly deployed complex enterprise systems--large-scale packaged software "innovations" that integrate and automate…

  20. Organizational Agility and Complex Enterprise System Innovations: A Mixed Methods Study of the Effects of Enterprise Systems on Organizational Agility

    ERIC Educational Resources Information Center

    Kharabe, Amol T.

    2012-01-01

    Over the last two decades, firms have operated in "increasingly" accelerated "high-velocity" dynamic markets, which require them to become "agile." During the same time frame, firms have increasingly deployed complex enterprise systems--large-scale packaged software "innovations" that integrate and automate…

  1. Dipyridyl β-diketonate complexes and their use as metalloligands in the formation of mixed-metal coordination networks.

    PubMed

    Burrows, Andrew D; Mahon, Mary F; Renouf, Catherine L; Richardson, Christopher; Warren, Anna J; Warren, John E

    2012-04-14

    The iron(III) and aluminium(III) complexes of 1,3-di(4-pyridyl)propane-1,3-dionato (dppd) and 1,3-di(3-pyridyl)propane-1,3-dionato (dmppd), [Fe(dppd)(3)] 1, [Fe(dmppd)(3)] 2, [Al(dppd)(3)] 3 and [Al(dmppd)(3)] 4 have been prepared. These complexes adopt molecular structures in which the metal centres contain distorted octahedral geometries. In contrast, the copper(II) and zinc(II) complexes [Cu(dppd)(2)] 5 and [Zn(dmppd)(2)] 6 both form polymeric structures in which coordination of the pyridyl groups into the axial positions of neighbouring metal centres links discrete square-planar complexes into two-dimensional networks. The europium complex [Eu(dmppd)(2)(H(2)O)(4)]Cl·2EtOH·0.5H(2)O 7 forms a structure containing discrete cations that are linked into sheets through hydrogen bonds, whereas the lanthanum complex [La(dmppd)(3)(H(2)O)]·2H(2)O 8 adopts a one-dimensional network structure, connected into sheets by hydrogen bonds. The iron complexes 1 and 2 act as metalloligands in reactions with silver(I) salts, with the nature of the product depending on the counter-ions present. Thus, the reaction between 1 and AgBF(4) gave [AgFe(dppd)(3)]BF(4)·DMSO 9, in which the silver centres link the metalloligands into discrete nanotubes, whereas reactions with AgPF(6) and AgSbF(6) gave [AgFe(dppd)(3)]PF(6)·3.28DMSO 10 and [AgFe(dppd)(3)]SbF(6)·1.25DMSO 11, in which the metalloligands are linked into sheets. In all three cases, only four of the six pyridyl groups present on the metalloligands are coordinated. The reaction between 2 and AgNO(3) gave [Ag(2)Fe(dmppd)(3)(ONO(2))]NO(3)·MeCN·CH(2)Cl(2)12. Compound 12 adopts a layer structure in which all pyridyl groups are coordinated to silver centres and, in addition, a nitrate ion bridges between two silver centres. A similar structure is adopted by [Ag(2)Fe(dmppd)(3)(O(2)CCF(3))]CF(3)CO(2)·2MeCN·0.25CH(2)Cl(2)13, with a bridging trifluoroacetate ion playing the same role as the nitrate ion in 12.

  2. Mixed methods research.

    PubMed

    Halcomb, Elizabeth; Hickman, Louise

    2015-04-08

    Mixed methods research involves the use of qualitative and quantitative data in a single research project. It represents an alternative methodological approach, combining qualitative and quantitative research approaches, which enables nurse researchers to explore complex phenomena in detail. This article provides a practical overview of mixed methods research and its application in nursing, to guide the novice researcher considering a mixed methods research project.

  3. A Comparative Analysis of Reynolds-Averaged Navier-Stokes Model Predictions for Rayleigh-Taylor Instability and Mixing with Constant and Complex Accelerations

    NASA Astrophysics Data System (ADS)

    Schilling, Oleg

    2016-11-01

    Two-, three- and four-equation, single-velocity, multicomponent Reynolds-averaged Navier-Stokes (RANS) models, based on the turbulent kinetic energy dissipation rate or lengthscale, are used to simulate At = 0 . 5 Rayleigh-Taylor turbulent mixing with constant and complex accelerations. The constant acceleration case is inspired by the Cabot and Cook (2006) DNS, and the complex acceleration cases are inspired by the unstable/stable and unstable/neutral cases simulated using DNS (Livescu, Wei & Petersen 2011) and the unstable/stable/unstable case simulated using ILES (Ramaprabhu, Karkhanis & Lawrie 2013). The four-equation models couple equations for the mass flux a and negative density-specific volume correlation b to the K- ɛ or K- L equations, while the three-equation models use a two-fluid algebraic closure for b. The lengthscale-based models are also applied with no buoyancy production in the L equation to explore the consequences of neglecting this term. Predicted mixing widths, turbulence statistics, fields, and turbulent transport equation budgets are compared among these models to identify similarities and differences in the turbulence production, dissipation and diffusion physics represented by the closures used in these models. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  4. [Effect of Invasive Herb Species on the Structure of Soil Yeast Complexes in Mixed Forests Exemplified by Impatiens parviflora DC].

    PubMed

    Glushakova, A M; Kachalkin, A V; Chernov, I Yu

    2015-01-01

    Yeast abundance and diversity in a mixed forest sod-podzol soil under Impatiens parviflora DC plants was studied in comparison with unimpaired aboriginal herbaceous plants typical of the Mid-Russian secondary, after-forest meadow. The study was carried out throughout the vegetation period. Standard microbiological plating techniques revealed 36 yeast species. Typical pedobiotic (Cryptococcus podzolicus, Wickerhamomyces anomalus) and eurybiotic yeast species (Rhodotorula mucilaginosa) predominated in both biotopes. The relative abundance of the autochthonous soil yeast species Cryptococcus podzolicus was higher in the soil under aboriginal herbs than under Impatiens parviflora. Sites with aboriginal vegetation were also characterized by high abundance of the pedogamous species Schwanniomyces castelli and Torulaspora delbrueckii. The share of yeastlike Trichosporon fungi with high hydrolytic activity was considerably higher under adventitious plants Impatiens parviflora, as well as in the previously studied soil under Heracleum sosnowskyi.

  5. Synthesis, NMR spectral and structural studies on mixed ligand complexes of Pd(II) dithiocarbamates: First structural report on palladium(II) dithiocarbamate with SCN-ligand

    NASA Astrophysics Data System (ADS)

    Prakasam, Balasubramaniam Arul; Lahtinen, Manu; Peuronen, Anssi; Muruganandham, Manickavachagam; Kolehmainen, Erkki; Haapaniemi, Esa; Sillanpää, Mika

    2016-03-01

    Three new mixed ligand complexes of palladium(II) dithiocarbamates; [Pd(4-dpmpzdtc)(PPh3)(SCN)] (1), [Pd(4-dpmpzdtc)(PPh3)Cl] (2) and [Pd(bzbudtc)(PPh3)Cl] (3), (where, 4-dpmpzdtc = 4-(diphenylmethyl)piperazinecarbodithioato anion, bzbudtc = N-benzyl-N-butyldithiocarbamato anion and PPh3 = triphenylphosphine) have been synthesized from their respective parent dithiocarbamates by ligand exchange reactions and characterized by IR and NMR (1H, 13C and 31P) spectroscopy. IR and NMR spectral data support the isobidentate coordination of the dithiocarbamate ligands in all complexes (1-3) in solid and in solution, respectively. Single crystal diffraction analysis of complexes 1-3 evidences that all three complexes are exhibiting distorted square planar geometry. The Pd-S distances in 1-3 vary in accordance with the differences in trans influences of PPh3, SCN- and Cl- and it is in the order of PPh3 > SCN- > and Cl-. Interchange of the anionic auxiliary ligand (SCN- to Cl-) induces asymmetry to the dithiocarbamate-metal bonds. Thioureide C-N bond distances are short in 1-3, supporting a contribution of thioureide form to the structures. The observed distortions in the square planar geometry for 1-3, are in the order of 1 > 2 > 3.

  6. Doubly end-on azido bridged mixed-valence cobalt trinuclear complex: Spectral study, VTM, inhibitory effect and antimycobacterial activity on human carcinoma and tuberculosis cells

    NASA Astrophysics Data System (ADS)

    Datta, Amitabha; Das, Kuheli; Sen, Chandana; Karan, Nirmal Kumar; Huang, Jui-Hsien; Lin, Chia-Her; Garribba, Eugenio; Sinha, Chittaranjan; Askun, Tulin; Celikboyun, Pinar; Mane, Sandeep B.

    2015-09-01

    Doubly end-on azido-bridged mixed-valence trinuclear cobalt complex, [Co3(L)2(N3)6(CH3OH)2] (1) is afforded by employing a potential monoanionic tetradentate-N2O2 Schiff base precursor (2-[{[2-(dimethylamino)ethyl]imino}methyl]-6-methoxyphenol; HL). Single crystal X-ray structure reveals that in 1, the adjacent CoII and CoIII ions are linked by double end-on azido bridges and thus the full molecule is generated by the site symmetry of a crystallographic twofold rotation axis. Complex 1 is subjected on different spectral analysis such as IR, UV-vis, emission and EPR spectroscopy. On variable temperature magnetic study, we observe that during cooling, the χMT values decrease smoothly until 15 K and then reaches to the value 1.56 cm3 K mol-1 at 2 K. Complex 1 inhibits the cell growth on human lung carcinoma (A549 cells), human colorectal (COLO 205 and HT-29 cells), and human heptacellular (PLC5 cells) carcinoma cells. Complex 1 exhibits anti-mycobacterial activity and considerable efficacy on Mycobacterium tuberculosis H37Rv ATCC 27294 and H37Ra ATCC 25177 strains.

  7. X-ray absorption fine structure (XAFS) studies of copper (II) mixed ligand complexes having tetramethylethylenediamine as one of the ligands

    NASA Astrophysics Data System (ADS)

    Sharma, Sharad; Joshi, S. K.; Shrivastava, B. D.; Hinge, V. K.; Prasad, J.; Srivastava, K.

    2014-09-01

    X-ray absorption fine structure (XAFS) has been studied at the K-edge of copper in copper(II) mixed ligand complexes, having tetramethylethylenediamine (tmen) as one of the ligands, viz., Cu(tmen)(gly)ClO4, Cu(tmen)(bipy)(ClO4)2 and Cu(tmen)(phen)(ClO4)2. The spectra have been recorded at the dispersive XAFS beamline (BL-8) at the 2.5 GeV INDUS-2 synchrotron, RRCAT, Indore, India. The data obtained has been processed and analyzed using the computer program Athena. It has been observed that K-edge has been found to split in two edges, K and K', in each of the complex. The chemical shift has been utilized to determine the oxidation state of copper in the complexes and also the effective nuclear charge (ENC). The EXAFS data has been analyzed to obtain the bond lengths in the complexes using Levy's, Lytle's and Lytle, Sayers and Stern's (LSS) methods. The first peak in the Fourier transform of the spectra gives the value of first shell phase uncorrected bond length. The results obtained from the Fourier transformation and LSS methods are in good agreement.

  8. Synthesis and characterisation of a novel mixed donor P,O,P' nixantphos ligand and its metal complex

    NASA Astrophysics Data System (ADS)

    Marimuthu, Thashree; Bala, Muhammad D.; Friedrich, Holger B.

    2016-02-01

    The complex [(NixC8OH)Ir(cod)Cl] 4 has been synthesized and structurally characterized by NMR, IR and single crystal X-ray diffraction. The synthesis and characterisation of the novel ligand NixC8OH is also presented. The coordination around Ir is trigonal bipyramidal with both P groups of the NixC8OH ligand bound in a bis-equatorial mode. The bis-chelating cod (C8H12) ligand occupies the remaining equatorial position and an axial position. This mode of bonding has resulted in a large bite angle (P1-Ir-P2) of 102.92(12)° for the title complex 4. The IR and NMR data further support the elucidated structure. Thermal analyses of 4 indicate that it is thermally stable up to a decomposition temperature of >400 °C.

  9. Mixed-ligand copper(II) complexes activate aryl hydrocarbon receptor AhR and induce CYP1A genes expression in human hepatocytes and human cell lines.

    PubMed

    Kubešová, Kateřina; Dořičáková, Aneta; Trávníček, Zdeněk; Dvořák, Zdeněk

    2016-07-25

    The effects of four copper(II) mixed-ligand complexes [Cu(qui1)(L)]NO3·H2O (1-3) and [Cu(qui2)(phen)]NO3 (4), where qui1=2-phenyl-3-hydroxy-4(1H)-quinolinone, Hqui2=2-(4-amino-3,5-dichlorophenyl)-N-propyl-3-hydroxy-4(1H)-quinolinone-7-carboxamide, L=1,10-phenanthroline (phen) (1), 5-methyl-1,10-phenanthroline (mphen) (2), bathophenanthroline (bphen) (3), on transcriptional activities of steroid receptors, nuclear receptors and xenoreceptors have been studied. The complexes (1-4) did not influence basal or ligand-inducible activities of glucocorticoid receptor, androgen receptor, thyroid receptor, pregnane X receptor and vitamin D receptor, as revealed by gene reporter assays. The complexes 1 and 2 dose-dependently induced luciferase activity in stable gene reporter AZ-AhR cell line, and this induction was reverted by resveratrol, indicating involvement of aryl hydrocarbon receptor (AhR) in the process. The complexes 1, 2 and 3 induced CYP1A1 mRNA in LS180 cells and CYP1A1/CYP1A2 in human hepatocytes through AhR. Electrophoretic mobility shift assay EMSA showed that the complexes 1 and 2 transformed AhR in its DNA-binding form. Collectively, we demonstrate that the complexes 1 and 2 activate AhR and induce AhR-dependent genes in human hepatocytes and cancer cell lines. In conclusion, the data presented here might be of toxicological importance, regarding the multiple roles of AhR in human physiology and pathophysiology.

  10. Unusual saccharin-N,O (carbonyl) coordination in mixed-ligand copper(II) complexes: Synthesis, X-ray crystallography and biological activity

    NASA Astrophysics Data System (ADS)

    Mokhtaruddin, Nur Shuhada Mohd; Yusof, Enis Nadia Md; Ravoof, Thahira B. S. A.; Tiekink, Edward R. T.; Veerakumarasivam, Abhi; Tahir, Mohamed Ibrahim Mohamed

    2017-07-01

    Three tridentate Schiff bases containing N and S donor atoms were synthesized via the condensation reaction between S-2-methylbenzyldithiocarbazate with 2-acetyl-4-methylpyridine (S2APH); 4-methyl-3-thiosemicarbazide with 2-acetylpyridine (MT2APH) and 4-ethyl-3-thiosemicarbazide with 2-acetylpyridine (ET2APH). Three new, binuclear and mixed-ligand copper(II) complexes with the general formula, [Cu(sac)(L)]2 (sac = saccharinate anion; L = anion of the Schiff base) were then synthesized, and subsequently characterized by IR and UV/Vis spectroscopy as well as by molar conductivity and magnetic susceptibility measurements. The Schiff bases were also spectroscopically characterized using NMR and MS to further confirm their structures. The spectroscopic data indicated that the Schiff bases behaved as a tridentate NNS donor ligands coordinating via the pyridyl-nitrogen, azomethine-nitrogen and thiolate-sulphur atoms. Magnetic data indicated a square pyramidal environment for the complexes and the conductivity values showed that the complexes were essentially non-electrolytes in DMSO. The X-ray crystallographic analysis of one complex, [Cu(sac)(S2AP)]2 showed that the Cu(II) atom was coordinated to the thiolate-S, azomethine-N and pyridyl-N donors of the S2AP Schiff base and to the saccharinate-N from one anion, as well as to the carbonyl-O atom from a symmetry related saccharinate anion yielding a centrosymmetric binuclear complex with a penta-coordinate, square pyramidal geometry. All the copper(II) saccharinate complexes were found to display strong cytotoxic activity against the MCF-7 and MDA-MB-231 human breast cancer cell lines.

  11. Two novel 3D copper(II) complexes based on a rigid bis-pyridyl-bis-amide and two polycarboxylates mixed ligands: Assembly, structures and properties

    NASA Astrophysics Data System (ADS)

    Wang, Xiu-Li; Mu, Bao; Lin, Hong-Yan; Yang, Song; Liu, Guo-Cheng

    2013-03-01

    Two novel three-dimensional (3D) copper(II) complexes [Cu3(3-bpcb)(1,2-BDC)2(μ2-OH)2] (1) and [Cu2(3-bpcb)1.5(SIP)(μ3-OH)]·H2O (2), based on a rigid bis-pyridyl-bis-amide ligand [3-bpcb = N,N'-bis(3-pyridinecarboxamide)-1,4-benzene] and two different polycarboxylates [1,2-H2BDC = 1,2-benzenedicarboxylic acid, NaH2SIP = sodium 5-sulfoisophthalic acid] have been prepared under hydrothermal conditions. Single crystal X-ray diffraction analysis shows that complex 1 exhibits a 4-nodal mixed (3,4,4,5)-connected 3D structure with the (3·4·5)2(3·42·5·86)2(32·8·92·10)(42·82·102) Schläfli symbol, which is constructed from two-dimensional (2D) Cu(II)-μ2-OH-3-bpcb layers (3-bpcb: μ4-bridging coordination mode via two pyridyl nitrogen and two carbonyl oxygen atoms) and the 1,2-BDC bridging ligands. Complex 2 is also a 3D coordination polymer constructed from the μ2-bridging 3-bpcb ligands (via two pyridyl nitrogen atoms) and the 2D Cu(II)-μ3-OH-SIP sheets containing tetranuclear copper clusters, showing a novel 3-nodal (5,6,6)-connected (33·43·53·63·72·8)(33·43·53·6)(33·46·54·62) topology. The differences between the final 3D structures for complexes 1 and 2 might be attributed to the different aromatic polycarboxylates and the bis-pyridyl-bis-amide ligand with different coordination modes. Moreover, the electrochemical behavior of complex 1 and the fluorescence properties of the complexes 1-2 have been investigated.

  12. Spectral and redox studies on mixed ligand complexes of cobalt(III) phenanthroline/bipyridyl and benzoylhydrazones, their DNA binding and antimicrobial activity.

    PubMed

    Srinivasan, S; Annaraj, J; Athappan, Pr

    2005-03-01

    Cobalt(III) complexes of the type [Co(N-N)2L](ClO4)2.H2O [where L=anionic form of para-substituted benzaldehyde-benzoylhydrazone (BHBX-); X=H, Me, OMe, OH, Cl or NO2; N-N=2,2'-bipyridine (bpy) or 1,10-phenanthroline (phen)] have been synthesized and characterized through UV-Vis, IR, NMR and electrochemical studies. The IR spectral frequencies support the mode of coordination of BHBX to the metal through the imino nitrogen and enolic oxygen atoms. The electronic absorption spectra exhibit metal to ligand charge transfer (MLCT) transition around 450 nm together with intraligand (IL) bands that are comparable to that of [Co(phen/bpy)3]3+. In acetonitrile solution these complexes show two well defined redox couples corresponding to Co(III/II) and Co(II/I) processes. Binding of these complexes with herring sperm DNA have been investigated by spectroscopic and voltammetric methods. The lower binding constant values of these complexes with respect to the [Co(phen/bpy)3]3+ are ascribed to the polar interaction of the substituted benzoylhydrazone moiety with the sugar-phosphate backbone of the DNA. The UV spectrum shows reasonable hypochromism with slight (2-4 nm) red shift, while the cyclic voltammogram shows decrease in current intensity along with a very small shift in the formal potential of the Co(III/II) redox couple. These experimental results indicate that phen mixed ligand complexes bind to DNA through an intercalative mode more effectively than their bpy counterparts. These complexes are also found to have good antimicrobial activity.

  13. Insights into bonding interactions and excitation energies of 3d-4f mixed lanthanide transition metal macrocyclic complexes.

    PubMed

    Rabanal-León, Walter A; Murillo-López, Juliana A; Arratia-Pérez, Ramiro

    2016-12-07

    In this contribution, a computational study of equatorial bound tetranuclear macrocycle (butylene linked) [LnZn(HOM(Bu))](3+) (Ln = La(3+), Ce(3+)) complexes was carried out. Here, the electronic structure, bonding interaction and excitation energies were studied within the relativistic density functional theory framework. From the electronic structure analysis, the frontier molecular orbitals (FMOs) were strongly localized in the d-orbitals of the Zn centers and the f-orbitals of the lanthanide ions. Besides, the inner MOs were found to exhibit a π-character from the organic part of the macrocyclic chain. EDA-NOCV was used as a tool for evaluating the bonding interaction, taking the trinuclear metallomacrocycle (ZnHOM(Bu)) and the lanthanide center as fragments. This analysis showed that the interaction between these fragments was slightly covalent; with this covalency being the result of a charge transfer from the metallomacrocyclic ring to the lanthanide. This phenomenon was observed in the deformation density channels obtained from the EDA-NOCV study; in which π- and σ-charge transfer was observed. Finally, the TD-DFT study of the excitation energies evidenced three sets of bands: the first set with the highest intensity represented the ligand to metal charge transfer bands; the second set could be attributed to the 3d-4f electronic transitions between the metal centers; and the third set represented the f-f bands found for the open-shell cerium complex. This class of complexes accomplishes the "antenna effect" principle, which states that highly absorptive transition-metal (TM) complexes can be used to enhance the luminescence of poorly emissive systems, and are introduced in this study as self-sensitizer bimetallic d-f systems with potential applications in near infra-red (NIR) technologies.

  14. Versatile Reactivity and Theoretical Evaluation of Mono- and Dinuclear Oxidovanadium(V) Compounds of Aroylazines: Electrogeneration of Mixed-Valence Divanadium(IV,V) Complexes.

    PubMed

    Dash, Subhashree P; Roy, Satabdi; Mohanty, Monalisa; Carvalho, M Fernanda N N; Kuznetsov, Maxim L; Pessoa, João Costa; Kumar, Amit; Patil, Yogesh P; Crochet, Aurélien; Dinda, Rupam

    2016-09-06

    The substituted hydrazones H2L(1-4) (L(1-4) = dibasic tridentate ONO(2-) donor ligands) obtained by the condensation of 2-hydroxy-1-naphthaldehyde and 2-aminobenzoylhydrazine (H2hnal-abhz) (H2L(1)) , 2-hydroxy-1-naphthaldehyde and 2-hydroxybenzoylhydrazine (H2hnal-hbhz) (H2L(2)), 2-hydroxy-1-acetonaphthone and benzoylhydrazine (H2han-bhz) (H2L(3)), or 2-hydroxy-1-acetonaphthone and 2-aminobenzoylhydrazine (H2han-abhz) (H2L(4)) are prepared and characterized. Reaction of ammonium vanadate with the appropriate H2L(1-4) results in the formation of oxidoethoxidovanadium(V) [V(V)O(OEt)(L(1-4))] (1-4) complexes. All compounds are characterized in the solid state and in solution by spectroscopic techniques (IR, UV-vis, (1)H, (13)C, and (51)V NMR, and electrospray ionization mass spectrometry). Single-crystal X-ray diffraction analysis of 1, 3, and 4 confirms the coordination of the corresponding ligands in the dianionic (ONO(2-)) enolate tautomeric form. In solution, the structurally characterized [V(V)O(OEt)(L)] compounds transform into the monooxido-bridged divanadium(V,V) [(V(V)OL)2-μ-O] complexes, with the processes being studied by IR and (1)H, (13)C, and (51)V NMR. The density functional theory (DFT) calculated Gibbs free energy of reaction 2[V(V)O(OEt)(L(4))] + H2O ⇆ [(V(V)OL(4))2-μ-O] + 2EtOH is only 2-3 kcal mol(-1), indicating that the dinuclear complexes may form in a significant amount. The electrochemical behavior of the complexes is investigated by cyclic voltammetry, with the V(V)-V(IV) E1/2(red) values being in the range 0.27-0.44 V (vs SCE). Upon controlled potential electrolysis, the corresponding (L)(O)V(IV)-O-V(V)(O)(L) mixed-valence species are obtained upon partial reduction of the [(V(V)OL)2-μ-O] complexes formed in solution, and some spectroscopic characteristics of these dinuclear mixed-valence complexes are investigated using DFT calculations and by electron paramagnetic resonance (EPR), with the formation of V(IV)-O-V(V) species being

  15. Diazido mixed-amine platinum(IV) anticancer complexes activatable by visible-light form novel DNA adducts.

    PubMed

    Zhao, Yao; Woods, Julie A; Farrer, Nicola J; Robinson, Kim S; Pracharova, Jitka; Kasparkova, Jana; Novakova, Olga; Li, Huilin; Salassa, Luca; Pizarro, Ana M; Clarkson, Guy J; Song, Lijiang; Brabec, Viktor; Sadler, Peter J

    2013-07-15

    Platinum diam(m)ine complexes, such as cisplatin, are successful anticancer drugs, but suffer from problems of resistance and side-effects. Photoactivatable Pt(IV) prodrugs offer the potential of targeted drug release and new mechanisms of action. We report the synthesis, X-ray crystallographic and spectroscopic properties of photoactivatable diazido complexes trans,trans,trans-[Pt(N3)2(OH)2(MA)(Py)] (1; MA=methylamine, Py=pyridine) and trans,trans,trans-[Pt(N3)2(OH)2(MA)(Tz)] (2; Tz=thiazole), and interpret their photophysical properties by TD-DFT modelling. The orientation of the azido groups is highly dependent on H bonding and crystal packing, as shown by polymorphs 1p and 1q. Complexes 1 and 2 are stable in the dark towards hydrolysis and glutathione reduction, but undergo rapid photoreduction with UVA or blue light with minimal amine photodissociation. They are over an order of magnitude more potent towards HaCaT keratinocytes, A2780 ovarian, and OE19 oesophageal carcinoma cells than cisplatin and show particular potency towards cisplatin-resistant human ovarian cancer cells (A2780cis). Analysis of binding to calf-thymus (CT), plasmids, oligonucleotide DNA and individual nucleotides reveals that photoactivated 1 and 2 form both mono- and bifunctional DNA lesions, with preference for G and C, similar to transplatin, but with significantly larger unwinding angles and a higher percentage of interstrand cross-links, with evidence for DNA strand cross-linking further supported by a comet assay. DNA lesions of 1 and 2 on a 50 bp duplex were not recognised by HMGB1 protein, in contrast to cisplatin-type lesions. The photo-induced platination reactions of DNA by 1 and 2 show similarities with the products of the dark reactions of the Pt(II) compounds trans-[PtCl2(MA)(Py)] (5) and trans-[PtCl2(MA)(Tz)] (6). Following photoactivation, complex 2 reacted most rapidly with CT DNA, followed by 1, whereas the dark reactions of 5 and 6 with DNA were comparatively slow

  16. Diazido Mixed-Amine Platinum(IV) Anticancer Complexes Activatable by Visible-Light Form Novel DNA Adducts

    PubMed Central

    Zhao, Yao; Woods, Julie A; Farrer, Nicola J; Robinson, Kim S; Pracharova, Jitka; Kasparkova, Jana; Novakova, Olga; Li, Huilin; Salassa, Luca; Pizarro, Ana M; Clarkson, Guy J; Song, Lijiang; Brabec, Viktor; Sadler, Peter J

    2013-01-01

    Platinum diam(m)ine complexes, such as cisplatin, are successful anticancer drugs, but suffer from problems of resistance and side-effects. Photoactivatable PtIV prodrugs offer the potential of targeted drug release and new mechanisms of action. We report the synthesis, X-ray crystallographic and spectroscopic properties of photoactivatable diazido complexes trans,trans,trans-[Pt(N3)2(OH)2(MA)(Py)] (1; MA=methylamine, Py=pyridine) and trans,trans,trans-[Pt(N3)2(OH)2(MA)(Tz)] (2; Tz=thiazole), and interpret their photophysical properties by TD-DFT modelling. The orientation of the azido groups is highly dependent on H bonding and crystal packing, as shown by polymorphs 1 p and 1 q. Complexes 1 and 2 are stable in the dark towards hydrolysis and glutathione reduction, but undergo rapid photoreduction with UVA or blue light with minimal amine photodissociation. They are over an order of magnitude more potent towards HaCaT keratinocytes, A2780 ovarian, and OE19 oesophageal carcinoma cells than cisplatin and show particular potency towards cisplatin-resistant human ovarian cancer cells (A2780cis). Analysis of binding to calf-thymus (CT), plasmids, oligonucleotide DNA and individual nucleotides reveals that photoactivated 1 and 2 form both mono- and bifunctional DNA lesions, with preference for G and C, similar to transplatin, but with significantly larger unwinding angles and a higher percentage of interstrand cross-links, with evidence for DNA strand cross-linking further supported by a comet assay. DNA lesions of 1 and 2 on a 50 bp duplex were not recognised by HMGB1 protein, in contrast to cisplatin-type lesions. The photo-induced platination reactions of DNA by 1 and 2 show similarities with the products of the dark reactions of the PtII compounds trans-[PtCl2(MA)(Py)] (5) and trans-[PtCl2(MA)(Tz)] (6). Following photoactivation, complex 2 reacted most rapidly with CT DNA, followed by 1, whereas the dark reactions of 5 and 6 with DNA were comparatively slow

  17. A software system used for load distribution at a combined heat and power plant with the complex mix of the equipment and complex schemes of heat and electric power supply

    NASA Astrophysics Data System (ADS)

    Makarch'yan, V. A.; Chernyaev, A. N.; Andryushin, A. V.; Pechenkin, S. P.; Lisitsa, V. I.; Logvinov, E. I.; Molchanov, A. Yu.

    2013-05-01

    The authors describe various approaches to construction of an algorithm for the solution of the problem of load distribution at a combined heat and power (CHP) plant with the complex mix of the equipment and complex schemes of heat and electrical energy supply on the basis of which the software system has been developed. Methods of obtaining energy characteristics of the equipment used for solving the problem of load distribution were studied. The results of the implementation of the software system for load distribution at the CHP-23 plant belonging to OAO Mosenergo are given. Realization of recommendations on maintaining an operational mode of the equipment with due regard for its optimal loading makes it possible to obtain fuel savings of up to 1%.

  18. Developing and evaluating the implementation of a complex intervention: using mixed methods to inform the design of a randomised controlled trial of an oral healthcare intervention after stroke.

    PubMed

    Brady, Marian C; Stott, David J; Norrie, John; Chalmers, Campbell; St George, Bridget; Sweeney, Petrina M; Langhorne, Peter

    2011-07-05

    Many interventions delivered within the stroke rehabilitation setting could be considered complex, though some are more complex than others. The degree of complexity might be based on the number of and interactions between levels, components and actions targeted within the intervention. The number of (and variation within) participant groups and the contexts in which it is delivered might also reflect the extent of complexity. Similarly, designing the evaluation of a complex intervention can be challenging. Considerations include the necessity for intervention standardisation, the multiplicity of outcome measures employed to capture the impact of a multifaceted intervention and the delivery of the intervention across different clinical settings operating within varying healthcare contexts. Our aim was to develop and evaluate the implementation of a complex, multidimensional oral health care (OHC) intervention for people in stroke rehabilitation settings which would inform the development of a randomised controlled trial. After reviewing the evidence for the provision of OHC following stroke, multi-disciplinary experts informed the development of our intervention. Using both quantitative and qualitative methods we evaluated the implementation of the complex OHC intervention across patients, staff and service levels of care. We also adopted a pragmatic approach to patient recruitment, the completion of assessment tools and delivery of OHC, alongside an attention to the context in which it was delivered. We demonstrated the feasibility of implementing a complex OHC intervention across three levels of care. The complementary nature of the mixed methods approach to data gathering provided a complete picture of the implementation of the intervention and a detailed understanding of the variations within and interactions between the components of the intervention. Information on the feasibility of the outcome measures used to capture impact across a range of components was

  19. Developing and evaluating the implementation of a complex intervention: using mixed methods to inform the design of a randomised controlled trial of an oral healthcare intervention after stroke

    PubMed Central

    2011-01-01

    Background Many interventions delivered within the stroke rehabilitation setting could be considered complex, though some are more complex than others. The degree of complexity might be based on the number of and interactions between levels, components and actions targeted within the intervention. The number of (and variation within) participant groups and the contexts in which it is delivered might also reflect the extent of complexity. Similarly, designing the evaluation of a complex intervention can be challenging. Considerations include the necessity for intervention standardisation, the multiplicity of outcome measures employed to capture the impact of a multifaceted intervention and the delivery of the intervention across different clinical settings operating within varying healthcare contexts. Our aim was to develop and evaluate the implementation of a complex, multidimensional oral health care (OHC) intervention for people in stroke rehabilitation settings which would inform the development of a randomised controlled trial. Methods After reviewing the evidence for the provision of OHC following stroke, multi-disciplinary experts informed the development of our intervention. Using both quantitative and qualitative methods we evaluated the implementation of the complex OHC intervention across patients, staff and service levels of care. We also adopted a pragmatic approach to patient recruitment, the completion of assessment tools and delivery of OHC, alongside an attention to the context in which it was delivered. Results We demonstrated the feasibility of implementing a complex OHC intervention across three levels of care. The complementary nature of the mixed methods approach to data gathering provided a complete picture of the implementation of the intervention and a detailed understanding of the variations within and interactions between the components of the intervention. Information on the feasibility of the outcome measures used to capture impact

  20. Complex catalytic behaviors of CuTiOx mixed-oxide during CO oxidation

    SciTech Connect

    Kim, Hyun You; Liu, Ping

    2015-09-21

    Mixed metal oxides have attracted considerable attention in heterogeneous catalysis due to the unique stability, reactivity, and selectivity. Here, the activity and stability of the CuTiOx monolayer film supported on Cu(111), CuTiOx/Cu(111), during CO oxidation was explored using density functional theory (DFT). The unique structural frame of CuTiOx is able to stabilize and isolate a single Cu+ site on the terrace, which is previously proposed active for CO oxidation. Furthermore, it is not the case, where the reaction via both the Langmuir–Hinshelwood (LH) and the Mars-van Krevelen (M-vK) mechanisms are hindered on such single Cu+ site. Upon the formation of step-edges, the synergy among Cuδ+ sites, TiOx matrix, and Cu(111) is able to catalyze the reaction well. Depending on temperatures and partial pressure of CO and O2, the surface structure varies, which determines the dominant mechanism. In accordance with our results, the Cuδ+ ion alone does not work well for CO oxidation in the form of single sites, while the synergy among multiple active sites is necessary to facilitate the reaction.

  1. Combining mixed titania morphologies into a complex assembly thin film by iterative block-copolymer-based sol–gel templating.

    PubMed

    Niedermeier, M A; Magerl, D; Zhong, Q; Nathan, A; Körstgens, V; Perlich, J; Roth, S V; Müller-Buschbaum, P

    2012-04-13

    Sol–gel templating combined with iterative spin-coating steps are used to custom-tailor hierarchically structured titania thin films. Using poly(styrene-block-ethylene oxide) P(S-b-PEO) as the structure directing agent, a foam-like structure is combined with nanogranules. Both structural elements are merged into a complex assembly in thin film geometry. The resulting morphology is pictured by SEM and probed with GISAXS. The installed mesoporous titania sandwich structure exhibits holes with a size of 45 nm which makes it promising for applications in photovoltaics or photocatalysis. An optical characterization completes the structural investigation.

  2. Synthesis and Assessment of Antibacterial Activities of Ruthenium(III) Mixed Ligand Complexes Containing 1,10-Phenanthroline and Guanide

    PubMed Central

    Hailemariam, Tizazu

    2016-01-01

    In this work, two complexes of ruthenium(III) ([Ru(phen)2Cl2]Cl·2H2O and [Ru(phen)2(G)Cl]2Cl·H2O) were synthesized from 1,10-phenanthroline alone as well as from both 1,10-phenanthroline and guanide. The synthesis was checked using halide test, conductance measurement, and spectroscopic (ICP-OES, FTIR, and UV/Vis) analysis. Their in vitro antibacterial activities were also investigated on two Gram-positive (Staphylococcus aureus (S. aureus) and methicillin resistant Staphylococcus aureus (MRSA)) and two Gram-negative (Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae)) bacteria. These complexes showed wide-range better activities than the commercially available controls (Chloramphenicol and Ciprofloxacin) against even the most drug resistant K. pneumoniae. [Ru(phen)2(G)Cl]2Cl·H2O inhibited S. aureus, MRSA, E. coli, and K. pneumoniae by 17.5%, 27.4%, 16%, and 52%, respectively, better than Chloramphenicol. It also inhibited these pathogens by 5.9%, 5.1%, 2.3%, and 17.2%, respectively, better than Ciprofloxacin. Similarly, [Ru(Phen)2(Cl)2]Cl·2H2O inhibited these pathogens by 11%, 8.7%, 0.1%, and 31.2%, respectively, better than Chloramphenicol. Therefore, after in vivo cytotoxicity investigations, these compounds can be considered as potential antibiotic drugs. PMID:27833473

  3. Selective enrichment media bias the types of Salmonella enterica strains isolated from mixed strain cultures and complex enrichment broths.

    PubMed

    Gorski, Lisa

    2012-01-01

    For foodborne outbreak investigations it can be difficult to isolate the relevant strain from food and/or environmental sources. If the sample is contaminated by more than one strain of the pathogen the relevant strain might be missed. In this study mixed cultures of Salmonella enterica were grown in one set of standard enrichment media to see if culture bias patterns emerged. Nineteen strains representing four serogroups and ten serotypes were compared in four-strain mixtures in Salmonella-only and in cattle fecal culture enrichment backgrounds using Salmonella enrichment media. One or more strain(s) emerged as dominant in each mixture. No serotype was most fit, but strains of serogroups C2 and E were more likely to dominate enrichment culture mixtures than strains of serogroups B or C1. Different versions of Rappaport-Vassiliadis (RV) medium gave different patterns of strain dominance in both Salmonella-only and fecal enrichment culture backgrounds. The fittest strains belonged to serogroups C1, C2, and E, and included strains of S. Infantis, S. Thompson S. Newport, S. 6,8:d:-, and S. Give. Strains of serogroup B, which included serotypes often seen in outbreaks such as S. Typhimurium, S. Saintpaul, and S. Schwarzengrund were less likely to emerge as dominant strains in the mixtures when using standard RV as part of the enrichment. Using a more nutrient-rich version of RV as part of the protocol led to a different pattern of strains emerging, however some were still present in very low numbers in the resulting population. These results indicate that outbreak investigations of food and/or other environmental samples should include multiple enrichment protocols to ensure isolation of target strains of Salmonella.

  4. A new mixed-ligand copper(II) complex of (E)-N";-(2-hydroxybenzylidene) acetohydrazide: Synthesis, characterization, NLO behavior, DFT calculation and biological activities

    NASA Astrophysics Data System (ADS)

    Yousef Ebrahimipour, S.; Sheikhshoaie, Iran; Crochet, Aurelien; Khaleghi, Moj; Fromm, Katharina M.

    2014-08-01

    A tridentate hydrazone Schiff base ligand, (E)-N";-(2-hydroxybenzylidene)acetohydrazide [HL], and its mixed-ligand Cu(II) complex [CuL(phen)], have been synthesized and characterized by elemental analyses, FT-IR, molar conductivity, UV-Vis spectroscopy. The structure of the complex has been determined by X-ray diffraction. This complex has square pyramidal geometry and the positions around central atom are occupied with donor atoms of Schiff base ligand and two nitrogens of 1,10-phenanthroline. Computational studies of compounds were performed by using DFT calculations. The linear polarizabilities and first hyperpolarizabilities of the studied molecules indicate that these compounds can be good candidates of nonlinear optical materials. It is in accordance with experimental data. In addition, invitro antimicrobial results show that these compounds specially [CuL(phen)] have great potential of antibacterial activity against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Listeria monocytogenes bacteria and antifungal activity against Candida Albicans in comparison to some standard drugs.

  5. A Non-Linear Mixed Spectral Finite-Difference 3-D Model of Planetary Boundary-Layer Flow over Complex Terrain and Its Application

    NASA Astrophysics Data System (ADS)

    Weng, W.; Taylor, P. A.

    2010-09-01

    Based on the early linear and Non-Linear Mixed Spectral Finite-Difference (MSFD and NLMSFD) models, a 3-D non-linear model of planetary boundary-layer flow (NLMSFD-PBL) was developed to study neutral PBL flow over complex terrain. The model assumes upwind or zero-order profiles of mean and turbulence variables about which perturbation quantities are calculated due to the effects of the terrain. In early models, the mean zero-order wind profile was assumed to be a simple logarithmic surface-layer profile and Reynolds stresses were constant throughout the depth of the model domain. This formally limits the applications of model to the surface-layer flow. The new model utilizes the results of early 1-D planetary boundary layer model of Weng and Taylor as the zero-order or upstream profiles of mean and turbulent quantities. The limitations associated with the original MSFD/NLMSFD model (e.g. logarithmic wind profile and constant shear stress layer) are relaxed. The effect of earth's rotation is also included in the model. Model results for planetary boundary-layer flow over complex terrain are discussed, particularly, the flow over Askervein hill - the site of a detailed and much referenced field study of flow over hills in the 1980s. This type of modelling of flow over complex terrain has important applications for wind energy resource assessment and wind farm design.

  6. Perchlorate mixed-ligand copper(II) complexes of beta-diketone and ethylene diamine derivatives: thermal, spectroscopic and biochemical studies.

    PubMed

    El-Ayaan, Usama; El-Metwally, Nashwa M; Youssef, Magdy M; El Bialy, Serry A A

    2007-12-31

    The present work carried out a study on perchlorate mixed-ligand copper(II) complexes which have been synthesized from ethylenediamine derivatives (3a-c) and beta-diketones. These complexes, namely [Cu(DA-Cl)(acac)H(2)O]ClO(4)4, [Cu(DA-Cl)(bzac)H(2)O]H(2)O.ClO(4)5, [Cu(DA-OMe)(acac)H(2)O]ClO(4)6, [Cu(DA-OMe)(bzac)H(2)O]ClO(4)7, [Cu(DA-H)(acac)H(2)O]2H(2)O.ClO(4)8 and [Cu(DA-H)(bzac)H(2)O]ClO(4)9 (where acac, acetylacetonate and bzac, benzoylacetonate) were characterized by elemental analysis, spectral (IR and UV-vis) and magnetic moment measurements. Thermal properties and decomposition kinetics of all complexes are investigated. The interpretation, mathematical analysis and evaluation of kinetic parameters (E, A, DeltaH, DeltaS and DeltaG) of all thermal decomposition stages have been evaluated using Coats-Redfern equation. The biochemical studies showed that, the diamines 3a-c have powerful effects on degradation of DNA and protein. The antibacterial screening demonstrated that, the diamine (DA-Cl), 3b has the maximum and broad activities against Gram +ve and Gram -ve bacterial strains.

  7. Perchlorate mixed-ligand copper(II) complexes of β-diketone and ethylene diamine derivatives: Thermal, spectroscopic and biochemical studies

    NASA Astrophysics Data System (ADS)

    El-Ayaan, Usama; El-Metwally, Nashwa M.; Youssef, Magdy M.; El Bialy, Serry A. A.

    2007-12-01

    The present work carried out a study on perchlorate mixed-ligand copper(II) complexes which have been synthesized from ethylenediamine derivatives ( 3a- c) and β-diketones. These complexes, namely [Cu(DA-Cl)(acac)H 2O]ClO 44, [Cu(DA-Cl)(bzac)H 2O]H 2O.ClO 45, [Cu(DA-OMe)(acac)H 2O]ClO 46, [Cu(DA-OMe)(bzac)H 2O]ClO 47, [Cu(DA-H)(acac)H 2O]2H 2O.ClO 48 and [Cu(DA-H)(bzac)H 2O]ClO 49 (where acac, acetylacetonate and bzac, benzoylacetonate) were characterized by elemental analysis, spectral (IR and UV-vis) and magnetic moment measurements. Thermal properties and decomposition kinetics of all complexes are investigated. The interpretation, mathematical analysis and evaluation of kinetic parameters ( E, A, Δ H, Δ S and Δ G) of all thermal decomposition stages have been evaluated using Coats-Redfern equation. The biochemical studies showed that, the diamines 3a- c have powerful effects on degradation of DNA and protein. The antibacterial screening demonstrated that, the diamine (DA-Cl), 3b has the maximum and broad activities against Gram +ve and Gram -ve bacterial strains.

  8. Synthesis, crystal structures and properties of three new mixed-ligand d10 metal complexes constructed from pyridinecarboxylate and in situ generated amino-tetrazole ligand

    NASA Astrophysics Data System (ADS)

    Liu, Dongsheng; Huang, Xihe; Huang, Changcang; Huang, Gansheng; Chen, Jianzhong

    2009-07-01

    Three new metal-organic frameworks, [Zn(atz)(nic)] n(1), [Zn(atz)(isonic)] n· nHisonic(2) and [Cd(atz)(isonic)] n(3) (Hnic=nicotinic acid, Hisonic=isonicotinic acid), have been firstly synthesized by employing mixed-ligand of pyridinecarboxylate with the in situ generated ligand of 5-amino-tetrazolate(atz -), and characterized by elemental analysis, IR spectroscopy, TGA and single crystal X-ray diffraction. The results revealed that 1 presents a two-dimensional (2D) "sql" topological network constructed from the linear chain subunit of Zn(nic) 2 and atz - ligand. A remarkable feature of 2 is a 2-fold interpenetrated diamondoid network with free Hisonic molecules locating in the channels formed by the zigzag chain subunits of Zn(isonic) 2. Complex 3 is a 3D non-interpenetrated pillared framework constructed from the double chain subunits of Cd-COO --Cd. It possesses a rarely observed (4,6)-connected " fsc" topology. The thermal stabilities and fluorescent properties of the complexes were investigated. All of these complexes exhibited intense fluorescent emissions in the solid state at room temperature.

  9. New nickel mixed-ligand complex containing 2-aminopyrimidine and 5-bromosalicylaldehyde with a one-dimensional hydrogen bonded structure

    NASA Astrophysics Data System (ADS)

    Buvaylo, Olena A.; Kokozay, Vladimir N.; Ischenko, Mykola V.; Vassilyeva, Olga Yu; Skelton, Brian W.

    2013-09-01

    The compound [Ni(PymNH2)2(5-BrSal-H)2]n·2dmf (PymNH2 = 2-aminopyrimidine, 5-BrSal = 5-bromosalicylaldehyde, dmf = dimethylformamide) has been synthesized and characterized by elemental analysis, X-ray crystallography and infrared spectroscopy. Mutual trans arrangement of the 2 + 2 organic ligands that octahedrally coordinate one nickel centre enables intramolecular H-bonds to further stabilize the neutral molecule and vice versa. In the crystal lattice, each PymNH2 ring forms a dimer with its inversion-related counterpart via a hydrogen atom of the amino group and the non-coordinated ring nitrogen. The packing motif of the self-complementary hydrogen bonded PymNH2 dimers, which form chains of the complex molecules, is the structure-determining factor in the present study. Dmf molecules of crystallization are accommodated on both sides of the dimers.

  10. Preparation and Single-Crystal X-Ray Structures of Four Related Mixed-Ligand 4-Methylpyridine Indium Halide Complexes

    NASA Technical Reports Server (NTRS)

    Hepp, Aloysius F.; Clark, Eric B.; Schupp, John D.; Williams, Jennifer N.; Duraj, Stan A.; Fanwick, Philip E.

    2013-01-01

    We describe the structures of four related indium complexes obtained during synthesis of solid-state materials precursors. Indium adducts of halides and 4-methylpyridine, InX3(pic)3 (X = Cl, Br; pic = 4-methylpyridine) consist of octahedral molecules with meridional (mer) geometry. Crystals of mer-InCl3(pic)3 (1) are triclinic, space group P1(bar) (No. 2), with a = 9.3240(3), b = 13.9580(6), c = 16.7268 (7) A, alpha = 84.323(2), beta = 80.938(2), gamma = 78.274(3)Z = 4, R = 0.035 for 8820 unique reflections. Crystals of mer-InBr3(pic)3 (2) are monoclinic, space group P21/n (No. 14), with a = 15.010(2), b = 19.938(2), c = 16.593(3), beta = 116.44(1)Z = 8, R = 0.053 for 4174 unique reflections. The synthesis and structures of related compounds with phenylsulfide (chloride) (3) and a dimeric complex with bridging hydroxide (bromide) (4) coordination is also described. Crystals of trans-In(SC6H5)Cl2(pic)3 (3) are monoclinic, space group P21/n (No. 14), with a = 9.5265(2), b = 17.8729(6), c = 13.8296(4), beta = 99.7640(15)Z = 4, R = 0.048 for 5511 unique reflections. Crystals of [In(mu-OH)Br2(pic)22 (4) are tetragonal, space group = I41cd (No. 110) with a = 19.8560(4), b = 19.8560(4), c = 25.9528(6), Z = 8, R = 0.039 for 5982 unique reflections.

  11. Crystal structures of two mixed-valence copper cyanide complexes with N-methyl­ethylenedi­amine

    PubMed Central

    Sabatino, Alexander

    2017-01-01

    The crystal structures of two mixed-valence copper cyanide compounds involving N-methyl­ethylenedi­amine (meen), are described. In compound (I), poly[bis(μ3-cyanido-κ3 C:C:N)tris(μ2-cyanido-κ2 C:N)bis(N-methylethane-1,2-di­amine-κ2 N,N′)tricopper(I)copper(II)], [Cu4(CN)5(C3H10N2)2] or Cu4(CN)5meen2, cyanide groups link CuI atoms into a three-dimensional network containing open channels parallel to the b axis. In the network, two tetra­hedrally bound CuI atoms are bonded by the C atoms of two end-on bridging CN groups to form Cu2(CN)6 moieties with the Cu atoms in close contact at 2.560 (1) Å. Other trigonally bound CuI atoms link these units together to form the network. The CuII atoms, coordinated by two meen units, are covalently linked to the network via a cyanide bridge, and project into the open network channels. In the mol­ecular compound (II), [(N-methylethylenediamine-κ2 N,N′)copper(II)]-μ2-cyanido-κ2 C:N-[bis(cyanido-κC)copper(I)] monohydrate, [Cu2(CN)3(C3H10N2)2]·H2O or Cu2(CN)3meen2·H2O, a CN group connects a CuII atom coordinated by two meen groups with a trigonal–planar CuI atom coordinated by CN groups. The mol­ecules are linked into centrosymmetric dimers via hydrogen bonds to two water mol­ecules. In both compounds, the bridging cyanide between the CuII and CuI atoms has the N atom bonded to CuII and the C atom bonded to CuI, and the CuII atoms are in a square-pyramidal coordination. PMID:28217329

  12. Symptom management in complex post-traumatic stress disorder (ICD-11), view and experience of patients and their relatives: a mixed methods approach (Research Proposal).

    PubMed

    Stadtmann, Manuel P; Maercker, Andreas; Binder, Jochen; Schnepp, Wilfried

    2017-09-07

    Using the framework of IDC-11, complex post-traumatic stress disorder will be diagnosed using the core criteria of a post-traumatic stress disorder and the presence of at least one symptom from the following three domains: symptoms of emotional dysregulation, negative self-concept, and problems in interpersonal relationships. In the literature, these symptoms are discussed as a common reason for seeking treatment. The symptoms can influence and impair the quality of life. This article describes a mixed methods study with a sequential exploratory design. The aim is to describe specific patient characteristics, levels of symptom burden and perspectives of adult inpatients and to describe the experiences, views and needs of patients' relatives. The study will also investigate facilitators of and barriers to symptom management. The research will be conducted in four phases. The first phase will assess patients' symptom burdens. The second phase will use semi-structured interviews to explore attitudes to symptom management and perceptions of patients and their relatives. The third phase will statistically explore hypotheses generated after the qualitative interviews. The fourth phase will mix the quantitative and qualitative results and interpret critically. The present study will add new results to the growing literature on complex post-traumatic stress disorder. These results could serve as the basis for further research into the development of interventions to improve symptom management. Trial registration Ethical approval has been obtained from the Swiss cantonal ethic commission (Nr. 201500096). This research was also registered to the World Health Organization Clinical Trials Search Portal through the German Clinical Trial Register, Trial DRKS00012268 (21/04/2017).

  13. Phenocryst complexity in andesites and dacites from the Tequila volcanic field, Mexico: resolving the effects of degassing vs. magma mixing

    NASA Astrophysics Data System (ADS)

    Frey, Holli M.; Lange, Rebecca A.

    2011-08-01

    The petrology of five phenocryst-poor (2-5%) andesites and dacites, all of which were erupted from different short-lived, monogenetic vents, is compared to that of phenocryst-rich (10-25%) andesites erupted from the adjacent stratovolcano, Volcán Tequila, in the Mexican arc. Despite differences in phenocryst abundances, these magmas have comparable phase assemblages (plagioclase + orthopyroxene + titanomagnetite + ilmenite + apatite ± augite ± hornblende), and similarly wide variations in phenocryst compositions, coupled to complex zoning patterns. For the phenocryst-poor lavas, equilibrium pairs of two Fe-Ti oxides lead to a narrow range of calculated temperatures for each sample that range from 934 (±24) to 1,073 (±6)°C and oxygen fugacities that range from +0.1 to +0.7 log units relative to the Ni-NiO buffer. Application of the plagioclase-liquid hygrometer to each sample at these calculated temperatures leads to maximum melt water concentrations of 4.6-3.1 wt% during plagioclase crystallization, indicating that the magmas were fluid saturated at depths ≥6.4-4.5 km. There is a wide, continuous range in the composition of plagioclase (≤44 mol% An) and orthopyroxene (≤16% Mg#) phenocrysts in each sample, which is consistent with a loss of dissolved water (≤2.8 wt%) from the melt phase during degassing as the magmas ascended rapidly to the surface. Evidence is presented that shows the effect of dissolved water is to reduce the activity of MgO relative to FeO in the melt phase, which indicates that degassing will also affect the Mg# of pyroxene phenocrysts, with higher melt water concentrations favoring Fe-rich pyroxene. Both plagioclase and orthopyroxene commonly display diffusion-limited growth textures (e.g., skeletal and hopper crystals, large interior melt hollows, and swallow tails), which are consistent with large undercoolings produced by degassing-induced crystallization. Therefore, degassing is proposed as a possible cause for the phenocryst

  14. Synthesis, characterisation, and preliminary anti-cancer photodynamic therapeutic in vitro studies of mixed-metal binuclear ruthenium(II)-vanadium(IV) complexes

    PubMed Central

    Taylor, Patrick; Magnusen, Anthony R.; Moffett, Erick T.; Meyer, Kyle; Hong, Yiling; Ramsdale, Stuart E.; Gordon, Michelle; Stubbs, Javelyn; Seymour, Luke A.; Acharya, Dhiraj; Weber, Ralph T.; Smith, Paul F.; Dismukes, G. Charles; Ji, Ping; Menocal, Laura; Bai, Fengwei; Williams, Jennie L.; Cropek, Donald M.; Jarrett, William L.

    2013-01-01

    We report the synthesis and characterisation of mixed-metal binuclear ruthenium(II)-vanadium(IV) complexes, which were used as potential photodynamic therapeutic agents for melanoma cell growth inhibition. The novel complexes, [Ru(pbt)2(phen2DTT)](PF6)2•1.5H2O 1 (where phen2DTT = 1,4-bis(1,10-phenanthrolin-5-ylsulfanyl)butane-2,3-diol and pbt = 2-(2'-pyridyl)benzothiazole) and [Ru(pbt)2(tpphz)](PF6)2•3H2O 2 (where tpphz = tetrapyrido[3,2-a:2′,3′-c:3″,2″-h:2‴,3‴-j]phenazine) were synthesised and characterised. Compound 1 was reacted with [VO(sal-L-tryp)(H2O)] (where sal-L-tryp = N-salicylidene-L-tryptophanate) to produce [Ru(pbt)2(phen2DTT)VO(sal-L-tryp)](PF6)2•5H2O 4; while [VO(sal-L-tryp)(H2O)] was reacted with compound 2 to produce [Ru(pbt)2(tpphz)VO(sal-L-tryp)](PF6)2•6H2O 3. All complexes were characterised by elemental analysis, HRMS, ESI MS, UV-visible absorption, ESR spectroscopy, and cyclic voltammetry, where appropriate. In vitro cell toxicity studies (with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay) via dark and light reaction conditions were carried out with sodium diaqua-4,4',4”,4”'tetrasulfophthalocyaninecobaltate(II) (Na4[Co(tspc)(H2O)2]), [VO(sal-L-tryp)(phen)]•H2O, and the chloride salts of complexes 3 and 4. Such studies involved A431, human epidermoid carcinoma cells; human amelanotic malignant melanoma cells; and HFF, non-cancerous human skin fibroblast cells. Both chloride salts of complexes 3 and 4 were found to be more toxic to melanoma cells than to non-cancerous fibroblast cells, and preferentially led to apoptosis of the melanoma cells over non-cancerous skin cells. The anti-cancer property of the chloride salts of complexes 3 and 4 was further enhanced when treated cells were exposed to light, while no such effect was observed on non-cancerous skin fibroblast cells. ESR and 51V NMR spectroscopic studies were also used to assess the stability of the chloride salts of

  15. Extraction of uranium and lead from mixed waste debris using a variety of metal/ligand complexes

    SciTech Connect

    Needham, D.A.; Duran, B.L.; Ehler, D.S.; Sauer, N.N.

    1997-12-31

    To ensure the safety of our Nation`s nuclear stockpile, Los Alamos National Laboratory is in the process of constructing the DARHT (Dual Axis Radiographic Hydrodynamic Test) facility. DARHT will examine the effects of aging and the stability of our stockpile. Contained testing will be phased in to reduce the impact of these tests, which contain depleted uranium, on our environment. The main focus of this research is to develop a treatment scheme for the recovery of depleted uranium and lead from shot debris that will result from these tests. The goals of this research are to optimize the conditions on a bench scale using a commercially available water soluble polymer to bind the lead and a variety of metal/ligand complexes such as 4,5-dihydroxy-1,3-benzene-disulfonic acid, dithionite, sodium carbonate/bicarbonate, and sodium hypochlorite to bind the uranium. Studies were conducted on a mixture of debris, such as wood, cable, paper towels, and tubing that contained both uranium and lead ranging in concentration from 10-1000`s of ppm of contaminants. Experiments were done varying combinations and successions of extractant solutions as well as a number of sequential extractions. Studies show that a mixture of sodium hypochlorite and carbonate removed 90+% of both uranium and lead. We then focused on a separation scheme for the lead and uranium.

  16. DNA and protein binding, double-strand DNA cleavage and cytotoxicity of mixed ligand copper(II) complexes of the antibacterial drug nalidixic acid.

    PubMed

    Loganathan, Rangasamy; Ganeshpandian, Mani; Bhuvanesh, Nattamai S P; Palaniandavar, Mallayan; Muruganantham, Amsaveni; Ghosh, Swapan K; Riyasdeen, Anvarbatcha; Akbarsha, Mohammad Abdulkader

    2017-09-01

    The water soluble mixed ligand complexes [Cu(nal)(diimine)(H2O)](ClO4) 1-4, where H(nal) is nalidixic acid and diimine is 2,2'-bipyridine (1), 1,10-phenanthroline (2), 5,6-dimethyl-1,10-phenanthroline (3), and 3,4,7,8-tetramethyl-1,10-phenanthroline (4), have been isolated. The coordination geometry around Cu(II) in 1 and that in the Density Functional Theory optimized structures of 1-4 has been assessed as square pyramidal. The trend in DNA binding constants (Kb) determined using absorption spectral titration (Kb: 1, 0.79±0.1<2, 1.06±0.1<3, 1.79±0.2<4, 1.84±0.2×10(5)M(-1)) is in line with that (Kapp) determined by competitive ethidium bromide binding studies. The large red-shift (10nm) observed for 2 suggests that the phen co-ligand is stacked with a frayed DNA base pair. In contrast, 3 and 4 are involved in intimate hydrophobic interaction with DNA through the methyl substituents on phen ring, which is supported by viscosity and protein binding studies. DNA docking studies imply that 4 is involved preferentially in DNA major groove binding while 1-3 in minor groove binding and that all the complexes, upon removing the axially coordinated water molecule, bind in the major groove. Interestingly, 3 and 4 display prominent double-strand DNA cleavage while 1 and 2 effect only single-strand DNA cleavage in the absence of an activator. The complexes 3 and 4 show cytotoxicity higher than 1 and 2 against human breast cancer cell lines (MCF-7). The complex 4 induces apoptotic mode of cell death in cancer cells. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Homo- and heterobimetallic niobium(v) and tantalum(v) peroxo-tartrate complexes and their use as molecular precursors for Nb-Ta mixed oxides.

    PubMed

    Bayot, Daisy; Tinant, Bernard; Devillers, Michel

    2005-03-07

    New water-soluble bimetallic peroxo-tartrato complexes of niobium(V) and/or tantalum(V) have been prepared, characterized from the structural and spectroscopic point of view, and used as molecular precursors for Nb-Ta mixed oxides. Two new homometallic complexes, (gu)5[Nb2(O2)4(tart)(Htart)] x 4H2O (1a) and (gu)6[Ta2(O2)4(tart)2] x 4H2O (2a), and the corresponding heterometallic complex, (gu)5[NbTa(O2)4(tart)(Htart)] x 4H2O (3), have been obtained. The crystal structures of the homometallic compounds, (gu)5[Nb2(O2)4(tart)(Htart)] x 6H2O x 1H2O2 (1b) and (gu)6[Ta2(O2)4(tart)2] x 6H2O (2b), have been determined, showing, for both cases, two 8-fold-coordinated metal atoms, each surrounded by oxygen atoms belonging to two bidentate peroxides, two monodentate carboxylato, and two alkoxo groups from both bridging tartrato ligands. The coordination polyhedron around each metal atom is a dodecahedron. The thermal treatment of complexes 1a, 2a, and 3 in air at 700 or 800 degrees C, depending of the Ta content, provided Nb2O5, Ta2O5, and the solid solution TaNbO5, respectively. The thermal treatment of a 1:1 Nb/Ta molar ratio mixture of 1a and 2a has also been studied. BET and SEM measurements have been carried out and reveal these oxides possess relatively high specific surface areas and display a porous character. Comparison between the use of homo- and heterometallic precursors is discussed.

  18. Mixed-metal supramolecular complexes coupling phosphine-containing Ru(II) light absorbers to a reactive Pt(II) through polyazine bridging ligands.

    PubMed

    Swavey, Shawn; Fang, Zhenglai; Brewer, Karen J

    2002-05-06

    Supramolecular bimetallic Ru(II)/Pt(II) complexes [(tpy)Ru(PEt(2)Ph)(BL)PtCl(2)](2+) and their synthons [(tpy)Ru(L)(BL)](n)()(+) (where L = Cl(-), CH(3)CN, or PEt(2)Ph; tpy = 2,2':6',2''-terpyridine; and BL = 2,2'-bipyrimidine (bpm) or 2,3-bis(2-pyridyl)pyrazine (dpp)) have been synthesized and studied by cyclic voltammetry, electronic absorption spectroscopy, mass spectral analysis, and (31)P NMR. The mixed-metal bimetallic complexes couple phosphine-containing Ru chromophores to a reactive Pt site. These complexes show how substitution of the monodentate ligand on the [(tpy)RuCl(BL)](+) synthons can tune the properties of these light absorbers (LA) and incorporate a (31)P NMR tag by addition of the PEt(2)Ph ligand. The redox potentials for the Ru(III/II) couples occur at values greater than 1.00 V versus the Ag/AgCl reference electrode and can be tuned to more positive potentials on going from Cl(-) to CH(3)CN or PEt(2)Ph (E(1/2) = 1.01, 1.55, and 1.56 V, respectively, for BL = bpm). The BL(0/-) couple at -1.03 (bpm) and -1.05 V (dpp) for [(tpy)Ru(PEt(2)Ph)(BL)](2+) shifts dramatically to more positive potentials upon the addition of the PtCl(2) moiety to -0.34 (bpm) and -0.50 V (dpp) for the [(tpy)Ru(PEt(2)Ph)(BL)PtCl(2)](2+) bridged complex. The lowest energy electronic absorption for these complexes is assigned as the Ru(d pi) --> BL(pi*) metal-to-ligand charge transfer (MLCT) transition. These MLCT transitions are tuned to higher energy in the monometallic synthons when Cl(-) is replaced by CH(3)CN or PEt(2)Ph (516, 452, and 450 nm, for BL = bpm, respectively) and to lower energy when Pt(II)Cl(2) is coordinated to the bridging ligand (560 and 506 nm for BL = bpm or dpp). This MLCT state displays a broad emission at room temperature for all the dpp systems with the [(tpy)Ru(PEt(2)Ph)(dpp)PtCl(2)](2+) system exhibiting an emission centered at 750 nm with a lifetime of 56 ns. These supramolecular complexes [(tpy)Ru(PEt(2)Ph)(BL)PtCl(2)](2+) represent the

  19. Novel Di- and Trinuclear Palladium Complexes Supported by N,N'-Diphosphanyl NHC Ligands and N,N'-Diphosphanylimidazolium Palladium, Gold, and Mixed-Metal Copper-Gold Complexes.

    PubMed

    Ai, Pengfei; Gourlaouen, Christophe; Danopoulos, Andreas A; Braunstein, Pierre

    2016-02-01

    The reaction of the trinuclear complex [Ag3(μ3-PC(NHC)P,κP,κC(NHC),κP)2](OTf)3 (Ag3; PC(NHC)P = N,N'-bis(di-tert-butylphosphanyl)imidazol-2-ylidene) with [Pd(dba)2] afforded the trinuclear palladium complex [Pd3(μ3-PC(NHC)P,κP,κC(NHC),κP)2](OTf)2 (Pd3) and the dinuclear palladium(I) complex [Pd2(μ2-PC(NHC)P,κP,κC(NHC),κP)2](OTf)2 (Pd2). The assignment of the oxidation state of the metals in the mixed-valence Pd3 chain as Pd(0)-Pd(II)-Pd(0) was based on the reactivity of the complex with 2,6-dimethylphenyl isocyanide and density functional theory calculations. Reaction of PCNHCP with [PdMe2(tmeda)] afforded the palladium(II) complex [PdMe2(PC(NHC)P,κP,κC(NHC))] (Pd-Me2), with PC(NHC)P acting as a bidentate ligand. The reaction of PC(NHC)P with [Pd(dba)2] led to a dinuclear palladium(0) complex [Pd2(μ2-PC(NHC)P,κP,κC(NHC),κP)](dba) (Pd2-dba); attempted replacement of the remaining dba by PC(NHC)P failed. The imidazolium triflate PCHP, precursor to PC(NHC)P, was reacted with [Pd2(dba)3]·CHCl3 to give the (2 + 2) metalla-mesocyclic cationic palladium(0) complex [Pd2(μ2-PCHP,κP,κP)2] (PCHP-Pd2), which resisted further deprotonation of the imidazolium cation. In contrast, PCHP reacted with [AuCl(tht)] to give [Au2Cl2(μ2-PCHP,κP,κP)] (PCHP-Au2), in which one Au-Cl moiety is bound to each P donor. Further reaction of PCHP-Au2 with [Au{N(SiMe3)2}(PPh3)] afforded a mixture of the trinuclear [Au3(μ3-PC(NHC)P,κP,κC(NHC),κP)2](OTf)3 (Au3) and [AuCl(PPh3)], while reaction with [CuMes]5, where Mes = 2,4,6-trimethylphenyl, resulted in a novel, centrosymmetric, heterometallic complex [Au2Mes2(Cu4Cl4)(PCHP,κP,κP)2] (PCHP-AuCu) featuring a new PCHP-AuMes metalloligand bridging a Cu···Cu diagonal of a Cu4Cl4 cubane via the P and AuMes functionalities.

  20. Mixed Self-Assembly of Polyethylene Glycol and Aptamer on Polydopamine Surface for Highly Sensitive and Low-Fouling Detection of Adenosine Triphosphate in Complex Media.

    PubMed

    Wang, Guixiang; Xu, Qingjun; Liu, Lei; Su, Xiaoli; Lin, Jiehua; Xu, Guiyun; Luo, Xiliang

    2017-09-13

    Detection of disease biomarkers within complex biological media is a substantial outstanding challenge because of severe biofouling and nonspecific adsorptions. Herein, a reliable strategy for sensitive and low-fouling detection of a biomarker, adenosine triphosphate (ATP) in biological samples was developed through the formation of a mixed self-assembled sensing interface, which was constructed by simultaneously self-assembling polyethylene glycol (PEG) and ATP aptamer onto the self-polymerized polydopamine-modified electrode surface. The developed aptasensor exhibited high selectivity and sensitivity toward the detection of ATP, and the linear range was 0.1-1000 pM, with a detection limit down to 0.1 pM. Moreover, owing to the presence of PEG within the sensing interface, the aptasensor was capable of sensing ATP in complex biological media such as human plasma with significantly reduced nonspecific adsorption effect. Assaying ATP in real biological samples including breast cancer cell lysates further proved the feasibility of this biosensor for practical application.

  1. Ytterbocenes as one- and two-electron reductants in their reactions with diazadienes: YbIII mixed-ligand bent-sandwich complexes containing a dianion of diazabutadiene.

    PubMed

    Trifonov, Alexander A; Borovkov, Ivan A; Fedorova, Elena A; Fukin, Georgii K; Larionova, Joulia; Druzhkov, Nikolai O; Cherkasov, Vladimir K

    2007-01-01

    Ytterbocene [Yb(C(5)MeH(4))(2)(thf)(2)] reacts with diazabutadiene 2,6-iPr(2)C(6)H(3)-N=CH-CH=N-C(6)H(3)iPr(2)-2,6 (DAD) as a one-electron reductant to afford a bis(cyclopentadienyl) Yb(III) derivative containing a DAD radical anion [Yb(C(5)MeH(4))(2)(dad(-.))]. However, ytterbocenes [YbCp*(2)(thf)(2)] (Cp*=C(5)Me(5), C(5)Me(4)H) coordinated by sterically demanding cyclopentadienyl ligands act as two-electron reductants in their reactions with DAD. These reactions occur by abstraction of one Cp* ring and result in the formation of novel Yb(III) mixed-ligand bent-sandwich complexes, [YbCp*(dad)(thf)], in which the dianion of DAD has an uncommon terminal eta(4)-coordination to the ytterbium atom. The variable-temperature magnetic measurements of complex [Yb(C(5)Me(5))(dad)(thf)] suggest the existence of redox tautomerism for this compound.

  2. Mixed ligand μ-phenoxo-bridged dinuclear copper(II) complexes with diimine co-ligands: efficient chemical nuclease and protease activities and cytotoxicity.

    PubMed

    Loganathan, Rangasamy; Ramakrishnan, Sethu; Suresh, Eringathodi; Palaniandavar, Mallayan; Riyasdeen, Anvarbatcha; Akbarsha, Mohamad Abdulkadhar

    2014-04-28

    The water soluble mixed ligand copper(II) complexes of the type [Cu(sal)(diimine)(ClO4)]21-5, where sal is salicylaldehyde and diimine is 2,2'-bipyridine (bpy, 1), 1,10-phenanthroline (phen, 2), 5,6-dimethyl-1,10-phenanthroline (5,6-dmp, 3), 3,4,7,8-tetramethyl-1,10-phenanthroline (3,4,7,8-tmp, 4) or dipyrido[3,2-d:2',3'-f]quinoxaline (dpq, 5), and [Cu(sal)(phen)(NO3)]2 (2a) have been successfully isolated and characterized by elemental analysis and other spectral techniques. The DNA binding and cleavage properties of 1-5 have been explored by using various physical and biochemical methods. The coordination geometry around copper(II) in the X-ray structures of 1, 2, 2a and 4 is described as an elongated octahedron. The UV-Vis and EPR spectral and ESI-MS studies reveal that in solution the dinuclear complexes dissociate into essentially mononuclear [Cu(sal)(diimine)]+ species with square-based geometry. The absorption spectral titrations and competitive DNA binding studies reveal that the intrinsic DNA binding affinity of the complexes depends upon the diimine co-ligand and is of the order of dpq (5) > 3,4,7,8-tmp (4) > 5,6-dmp (3) > phen (2) > bpy (1). The complexes 2 and 5 are involved in a partial intercalative interaction with DNA base pairs, while 3 and 4 are involved in a hydrophobic interaction with DNA and 1 is involved in an electrostatic interaction with DNA, which is supported by viscosity studies. Interestingly, only 3 and 4 are selective in exhibiting a positive induced CD band (ICD) upon binding to DNA suggesting that they induce a B to A conformational change in DNA. All the complexes exhibit an oxidative DNA cleavage ability, which varies as 5 > 4 > 3 > 2 > 1. While 4 and 5 are unique in displaying prominent double-strand DNA cleavage even in the absence of an activator, 2 and 3 display only single-strand DNA cleavage. Interestingly, all the complexes exhibit oxidative double-strand DNA cleavage in the presence of ascorbic acid, with 4 and 5 showing

  3. Using mixed methods to assess fidelity of delivery and its influencing factors in a complex self-management intervention for people with osteoarthritis and low back pain.

    PubMed

    Toomey, Elaine; Matthews, James; Hurley, Deirdre A

    2017-08-04

    Despite an increasing awareness of the importance of fidelity of delivery within complex behaviour change interventions, it is often poorly assessed. This mixed methods study aimed to establish the fidelity of delivery of a complex self-management intervention and explore the reasons for these findings using a convergent/triangulation design. Feasibility trial of the Self-management of Osteoarthritis and Low back pain through Activity and Skills (SOLAS) intervention (ISRCTN49875385), delivered in primary care physiotherapy. 60 SOLAS sessions were delivered across seven sites by nine physiotherapists. Fidelity of delivery of prespecified intervention components was evaluated using (1) audio-recordings (n=60), direct observations (n=24) and self-report checklists (n=60) and (2) individual interviews with physiotherapists (n=9). Quantitatively, fidelity scores were calculated using percentage means and SD of components delivered. Associations between fidelity scores and physiotherapist variables were analysed using Spearman's correlations. Interviews were analysed using thematic analysis to explore potential reasons for fidelity scores. Integration of quantitative and qualitative data occurred at an interpretation level using triangulation. Quantitatively, fidelity scores were high for all assessment methods; with self-report (92.7%) consistently higher than direct observations (82.7%) or audio-recordings (81.7%). There was significant variation between physiotherapists' individual scores (69.8% - 100%). Both qualitative and quantitative data (from physiotherapist variables) found that physiotherapists' knowledge (Spearman's association at p=0.003) and previous experience (p=0.008) were factors that influenced their fidelity. The qualitative data also postulated participant-level (eg, individual needs) and programme-level factors (eg, resources) as additional elements that influenced fidelity. The intervention was delivered with high fidelity. This study contributes

  4. Synthesis, structure, and electrochemical characterization of a mixed-ligand diruthenium(III,II) complex with an unusual arrangement of the bridging ligands.

    PubMed

    Ngubane, Siyabonga; Kadish, Karl M; Bear, John L; Van Caemelbecke, Eric; Thuriere, Antoine; Ramirez, Kevin P

    2013-03-14

    A mixed-ligand metal-metal bonded diruthenium complex having the formula Ru(2)(2,4,6-(CH(3))(3)ap)(3)(O(2)CCH(3))Cl where ap is the anilinopyridinate anion was synthesized from the reaction of Ru(2)(O(2)CCH(3))(4)Cl and H(2,4,6-(CH(3))(3)ap), after which the isolated product was structurally, spectroscopically and electrochemically characterized. The crystal structure reveals an unusual arrangement of the bridging ligands around the dimetal unit where one ruthenium atom is coordinated to one anilino and two pyridyl nitrogen atoms while the other ruthenium atom is coordinated to one pyridyl and two anilino nitrogen atoms. To our knowledge, Ru(2)(2,4,6-(CH(3))(3)ap)(3)(O(2)CCH(3))Cl is the only example of a mixed-ligand diruthenium complex of the type [Ru(2)L(3)(O(2)CCH(3))](+), where L is an unsymmetrical anionic bridging ligand that has been structurally characterized with a "(2,1)" geometric conformation of the bridging ligands, all others being "(3,0)". The initial Ru(2)(5+) compound in CH(2)Cl(2) or CH(3)CN containing 0.1 M tetra-n-butylammonium perchlorate (TBAP) undergoes up to four one-electron redox processes involving the dimetal unit. The Ru(2)(5+/4+) and Ru(2)(5+/6+) processes were characterized under N(2) using thin-layer UV-visible spectroelectrochemistry and this data is compared to UV-visible spectral changes obtained during similar electrode reactions for related diruthenium compounds having the formula Ru(2)L(4)Cl or Ru(2)L(3)(O(2)CCH(3))Cl where L is an anionic bridging ligand. Ru(2)(2,4,6-(CH(3))(3)ap)(3)(O(2)CCH(3))Cl was also examined by UV-visible and FTIR spectroelectrochemistry under a CO atmosphere and two singly reduced Ru(2)(4+) species, [Ru(2)(2,4,6-(CH(3))(3)ap)(3)(O(2)CCH(3))(CO)Cl](-) and Ru(2)(2,4,6-(CH(3))(3)ap)(3)(O(2)CCH(3))(CO) were in situ generated for further characterization. The CO-bound complexes could be further reduced and exhibited additional reductions to their Ru(2)(3+) and Ru(2)(2+) oxidation states.

  5. Redox-Induced Single-Molecule Magnetism in Mixed-Valent [2 × 2] Co4 Grid Complexes.

    PubMed

    Tong, Jin; Demeshko, Serhiy; John, Michael; Dechert, Sebastian; Meyer, Franc

    2016-05-02

    Homovalent [2 × 2] Co4 grid complexes [Co(II)4L(H)4](BF4)4 (1) and [Co(II)4L(Me)4](BF4)4 (2) with two new bis(terdentate) pyrazolate-bridged ligands, HL(H) = 3,5-bis(6-(1H-pyrazol-1-yl)pyrid-2-yl)pyrazole and HL(Me) = 4-methyl-3,5-bis(6-(1H-pyrazol-1-yl)pyrid-2-yl)pyrazole, were synthesized and comprehensively characterized. X-ray crystallographic analyses of 1 and 2 showed a square arrangement of cobalt(II) ions, each metal ion in distorted octahedral {N6} coordination created by two terdentate compartments from orthogonal ligand strands. Magnetic measurements revealed the metal ions' high-spin (S = 3/2) state and moderate antiferromagnetic interactions to give an overall diamagnetic ST = 0 ground state of 1 and 2. Twofold oxidation, electrochemically or chemically, led to the dimixed-valent [2 × 2] Co4 grids [Co(II)2Co(III)2L(H)4](BF4)6 (3) and [Co(II)2Co(III)2L(Me)4](BF4)6 (4). ESI mass spectrometry confirmed the ruggedness of all grids 1-4 and their integrity in solution, and analysis of the UV/vis/NIR spectra suggested moderate electronic coupling. Solution (1)H and (13)C NMR spectra of paramagnetic 1-4 were recorded and confirmed that the dimixed-valent Co(II)2Co(III)2 grids are charge-localized on the NMR time scale. X-ray crystallography revealed significant structural grid distortion upon oxidation, with the low-spin Co(III) at opposite corners and in almost octahedral {N6} environment but the remaining Co(II) ions' coordination sphere approaching a trigonal prism. SQUID studies showed the high-spin Co(II) to be magnetically isolated in the dimixed-valent Co(II)2Co(III)2 grids, and both 3 and 4 to display frequency-dependent peaks in the out-of-phase (χ") component of the alternating-current (ac) magnetic susceptibility data, characteristic for single molecule magnet (SMM) properties (with energy barriers Ueff/kB = 16 and 26 K, and relaxation times τ0 = 6.7·10(-6) and 5.0·10(-6) s for 3 and 4, respectively). The results are discussed in terms of

  6. Dissociation, shame, complex PTSD, child maltreatment and intimate relationship self-concept in dissociative disorder, chronic PTSD and mixed psychiatric groups.

    PubMed

    Dorahy, Martin J; Middleton, Warwick; Seager, Lenaire; McGurrin, Patrick; Williams, Mary; Chambers, Ron

    2015-02-01

    Whilst a growing body of research has examined dissociation and other psychiatric symptoms in severe dissociative disorders (DDs), there has been no systematic examination of shame and sense of self in relationships in DDs. Chronic child abuse often associated with severe DDs, like dissociative identity disorder, is likely to heighten shame and relationship concerns. This study investigated complex posttraumatic stress disorder (PTSD), borderline and Schneiderian symptoms, dissociation, shame, child abuse, and various markers of self in relationships (e.g., relationship esteem, relationship depression, fear of relationships). Participants were assessed via clinical interview with psychometrically sound questionnaires. They fell into three diagnostic groups, dissociative disorder (n=39; primarily dissociative identity disorder), chronic PTSD (Chr-PTSD; n=13) or mixed psychiatric presentations (MP; n=21; primarily mood and anxiety disorders). All participants had a history of child abuse and/or neglect, and the groups did not differ on age and gender. The DD group was higher on nearly all measured variables than the MP group, and had more severe dissociative, borderline and Schneiderian symptoms than the Chr-PTSD sample. Shame and complex PTSD symptoms fell marginally short of predicting reductions in relationship esteem, pathological dissociative symptoms predicted increased relationship depression, and complex PTSD symptoms predicted fear of relationships. The representativeness of the samples was unknown. Severe psychiatric symptoms differentiate DDs from chronic PTSD, while dissociation and shame have a meaningful impact on specific markers of relationship functioning in psychiatric patients with a history of child abuse and neglect. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. [Microclimate dynamics of pit and mound complex within different sizes of forest gaps in Pinus koraiensis-dominated broadleaved mixed forest].

    PubMed

    Wei, Quan-Shuai; Wang, Jing-Hua; Duan, Wen-Biao; Chen, Li-Xin; Wang, Ting; Han, Dong-Hui; Gu, Wei

    2014-03-01

    An investigation was conducted in a 2.25 hm2 plot of Pinus koraiensis-dominated broad-leaved mixed forest to study basic characteristics of 7 small gaps, 5 middle gaps, 3 large gaps and 7 closed stands within 38 pit and mound complexes caused by treefall in May 2012. From June to September 2012, the soil temperature, soil water content and relative humidity at five microsites (pit bottom, pit wall, mound top, mound face and undisturbed closed stands) were measured in six sunny days each month. The results showed that among the five microsites in every month, the mound top had the highest soil temperature and the lowest water content and relative humidity, and vice versa for the pit bottom. Mostly, the differences in the above indicators among the five microsites were significant. From June to September, the mean soil temperatures for all microsites at pit and mound complex in the various gaps and closed stands were in the order of large gap>middle gap >small gap>closed stand; but the soil water content ranked differently every month. In June, August and September, the mean relative humidities for all microsites in the various gaps and closed stands were in the order of closed stand>small gap>middle gap>large gap. Mostly, the differences in the above indicators between all microsites in the various gaps and closed stand were significant. The mean monthly soil temperature and relative humidity were highest in July, but lowest in September. The maximal mean monthly soil water content occurred in July and the minimal one in September for each microsite except the undisturbed closed stands, where the maximal mean monthly soil water content occurred in July. The variation of the microclimate at the pit and mound complex was mainly influenced by gap size, microsite, and time.

  8. Synthesis, molecular orbital, optical and device characterization of mononuclear mixed ligand nickel(II) complex of phthalate with N,N,N‧,N‧-tetramethylethylenediamine for photodiode applications

    NASA Astrophysics Data System (ADS)

    Taha, A.; Farag, A. A. M.; Shebl, Magdy; Ammar, A. H.; Ahmed, H. M.

    2016-01-01

    In this work, a new synthesized mononuclear mixed ligand nickel(II) complex was characterized by various techniques. Crystalline characteristics of [Ni(Phth)(Me4en)(H2O)2]·4H2O were studied by using transmission electron microscope(TEM). Well crystalline structure corresponds to the hexagonal crystal system and identified by selected area electron diffraction (SAED) were achieved. Coordination of the nickel(II) ion with the functional groups of the ligands was established from the IR spectrum. Molar conductance of the current complex in DMF (10-3 mol/L) indicated a non-electrolytic nature of the complex. Electronic spectra showed a strong band in the region 661-684 nm; MeCN (661 nm), CHCl3 (663 nm), MeOH (667 nm), Me2CO (675 nm), DMSO (682 nm) and DMF (684 nm) which can be assigned to 3A2g(F) → 3T1g(F) transition of an octahedral structure around nickel(II). Multiple peaks were easily resolved from the spectral dependence of the absorption coefficient (α) measurements and the analysis near the fundamental absorption edge showed two direct allowed transition with energy gaps of 1.18 and 2.53 eV. Dark current-voltage and capacitance-voltage characteristics of [Ni(Phth)(Me4en)(H2O)2]·4H2O/n-Si heterojunctions were studied to extract the main important parameters of the heterojunction device. The electrical characteristics of the heterojunction device under illumination hold the suitability of the device for optoelectronic applications.

  9. Synthesis, structure and spectral and redox properties of new mixed ligand monomeric and dimeric Ru(II) complexes: predominant formation of the "cis-alpha" diastereoisomer and unusual 3MC emission by dimeric complexes.

    PubMed

    Murali, Mariappan; Palaniandavar, Mallayan

    2006-02-07

    ligands maintain their tendency to fold themselves even in solution. The bis-mu-chloro dimers 1 and 2 show a spin-allowed but Laporte-forbidden t(2g)(6)((1)A(1g))--> t(2g)(5) e(g)(1)((1)T(1g), (1)T(2g)) d-d transition. They also display an intense Ru(II) dpi--> py/bzim (pi*) metal-to-ligand charge transfer (MLCT) transition. The mononuclear complexes 3-8 exhibit dpi-->pi* MLCT transitions in the range 340-450 nm. The binuclear complexes 1 and 2 exhibit a ligand field ((3)MC) luminescence even at room temperature, whereas the mononuclear complexes 3 and 4 show a ligand based radical anion ((3)MLCT) luminescence. The binuclear complexes 1 and 2 undergo two successive oxidation processes corresponding to successive Ru(II)/Ru(III) couples, affording a stable mixed-valence Ru(II)Ru(III) state (K(c): 1, 3.97 x 10(6); 2, 1.10 x 10(6)). The mononuclear complexes 3-7 exhibit only one while 8 shows two quasi-reversible metal-based oxidative processes. The coordinated 'soft' thioether raises the redox potentials significantly by stabilising the 'soft' Ru(II) oxidation state. One or two ligand-based reduction processes were also observed for the mononuclear complexes.

  10. Synthesis and characterization of d{sup 10} metal complexes with mixed 1,3-di(1H-imidazol-4-yl)benzene and multicarboxylate ligands

    SciTech Connect

    Chen, Zhi-Hao; Zhao, Yue; Chen, Shui-Sheng; Wang, Peng; Sun, Wei-Yin

    2013-06-15

    Seven new coordination polymers [Zn(H{sub 2}L)(mbdc)] (1), [Zn(H{sub 3}L)(btc)] (2), [Zn(H{sub 2}L)(Hbtc)] (3), [Zn(H{sub 2}L)(Hbtc)]·H{sub 2}O (4), [Zn{sub 2}(H{sub 2}L)(btc)(μ{sub 2}-OH)] (5), [Cd(H{sub 2}L)(mbdc)] (6) and [Cd{sub 3}(H{sub 2}L){sub 2}(btc){sub 2}(H{sub 2}O)]·5H{sub 2}O (7) were synthesized by reactions of the corresponding metal salt with rigid ligand 1,3-di(1H-imidazol-4-yl)benzene (H{sub 2}L) and different carboxylic acids of 1,3-benzenedicarboxylic acid (H{sub 2}mbdc) and benzene-1,3,5-tricarboxylic acid (H{sub 3}btc), respectively. The results of X-ray crystallographic analysis indicate that complex 1 is 1D chain while 2 is a (3,3)-connected 2D network with Point (Schläfli) symbol of (4,8{sup 2}). Complexes 3 and 6 are 2D networks, 4 is a 3-fold interpenetrating 3D framework with Point (Schläfli) symbol of (6{sup 5},8) and 5 is a (3,8)-connected 2D network with Point (Schläfli) symbol of (3,4{sup 2}){sub 2}(3{sup 4},4{sup 6},5{sup 6},6{sup 8},7{sup 3},8), while 7 is a (3,10)-connected 3D net with Schläfli symbol of (3,4,5){sub 2}(3{sup 4},4{sup 8},5{sup 18},6{sup 12},7{sup 2},8). The thermal stability and photoluminescence of the complexes were investigated. Furthermore, DFT calculations were performed for 2–4 to discuss the temperature controlled self-assembly of the complexes. - Graphical abstract: Seven new coordination polymers with multicarboxylate and rigid ditopic 4-imidazole containing ligands have been obtained and found to show different structures and topologies. - Highlights: • Metal complexes with diverse structures of 1D chain, 2D network and 3D framework. • Mixed ligands of 1,3-di(1H-imidazol-4-yl)benzene and multicarboxylate. • Photoluminescence property.

  11. Structural, EPR, and Mössbauer characterization of (μ-alkoxo)(μ-carboxylato)diiron(II,III) model complexes for the active sites of mixed-valent diiron enzymes.

    PubMed

    Li, Feifei; Chakrabarti, Mrinmoy; Dong, Yanhong; Kauffmann, Karl; Bominaar, Emile L; Münck, Eckard; Que, Lawrence

    2012-03-05

    To obtain structural and spectroscopic models for the diiron(II,III) centers in the active sites of diiron enzymes, the (μ-alkoxo)(μ-carboxylato)diiron(II,III) complexes [Fe(II)Fe(III)(N-Et-HPTB)(O(2)CPh)(NCCH(3))(2)](ClO(4))(3) (1) and [Fe(II)Fe(III)(N-Et-HPTB)(O(2)CPh)(Cl)(HOCH(3))](ClO(4))(2) (2) (N-Et-HPTB = N,N,N',N'-tetrakis(2-(1-ethyl-benzimidazolylmethyl))-2-hydroxy-1,3-diaminopropane) have been prepared and characterized by X-ray crystallography, UV-visible absorption, EPR, and Mössbauer spectroscopies. Fe1-Fe2 separations are 3.60 and 3.63 Å, and Fe1-O1-Fe2 bond angles are 128.0° and 129.4° for 1 and 2, respectively. Mössbauer and EPR studies of 1 show that the Fe(III) (S(A) = 5/2) and Fe(II) (S(B) = 2) sites are antiferromagnetically coupled to yield a ground state with S = 1/2 (g= 1.75, 1.88, 1.96); Mössbauer analysis of solid 1 yields J = 22.5 ± 2 cm(-1) for the exchange coupling constant (H = JS(A)·S(B) convention). In addition to the S = 1/2 ground-state spectrum of 1, the EPR signal for the S = 3/2 excited state of the spin ladder can also be observed, the first time such a signal has been detected for an antiferromagnetically coupled diiron(II,III) complex. The anisotropy of the (57)Fe magnetic hyperfine interactions at the Fe(III) site is larger than normally observed in mononuclear complexes and arises from admixing S > 1/2 excited states into the S = 1/2 ground state by zero-field splittings at the two Fe sites. Analysis of the "D/J" mixing has allowed us to extract the zero-field splitting parameters, local g values, and magnetic hyperfine structural parameters for the individual Fe sites. The methodology developed and followed in this analysis is presented in detail. The spin Hamiltonian parameters of 1 are related to the molecular structure with the help of DFT calculations. Contrary to what was assumed in previous studies, our analysis demonstrates that the deviations of the g values from the free electron value (g = 2) for the

  12. Initial application in the EACTS and STS Congenital Heart Surgery Databases of an empirically derived methodology of complexity adjustment to evaluate surgical case mix and results†

    PubMed Central

    Jacobs, Jeffrey Phillip; Jacobs, Marshall Lewis; Maruszewski, Bohdan; Lacour-Gayet, Francois G.; Tchervenkov, Christo I.; Tobota, Zdzislaw; Stellin, Giovanni; Kurosawa, Hiromi; Murakami, Arata; Gaynor, J. William; Pasquali, Sara K.; Clarke, David R.; Austin, Erle H.; Mavroudis, Constantine

    2012-01-01

    OBJECTIVES Outcomes evaluation is enhanced by assignment of operative procedures to appropriate categories based upon relative average risk. Formal risk modelling is challenging when a large number of operation types exist, including relatively rare procedures. Complexity stratification provides an alternative methodology. We report the initial application in the Congenital Heart Surgery Databases of the Society of Thoracic Surgeons (STS) and the European Association for Cardio-thoracic Surgery (EACTS) of an empirically derived system of complexity adjustment to evaluate surgical case mix and results. METHODS Complexity stratification is a method of analysis in which the data are divided into relatively homogeneous groups (called strata). A complexity stratification tool named the STS–EACTS Congenital Heart Surgery Mortality Categories (STAT Mortality Categories) was previously developed based on the analysis of 77 294 operations entered in the Congenital Heart Surgery Databases of EACTS (33 360 operations) and STS (43 934 patients). Procedure-specific mortality rate estimates were calculated using a Bayesian model that adjusted for small denominators. Operations were sorted by increasing risk and grouped into five categories (the STAT Mortality Categories) that were designed to minimize within-category variation and maximize between-category variation. We report here the initial application of this methodology in the EACTS Congenital Heart Surgery Database (47 187 operations performed over 4 years: 2006–09) and the STS Congenital Heart Surgery Database (64 307 operations performed over 4 years: 2006–09). RESULTS In the STS Congenital Heart Surgery Database, operations classified as STAT Mortality Categories 1–5 were (1): 17332, (2): 20114, (3): 9494, (4): 14525 and (5): 2842. Discharge mortality was (1): 0.54%, (2): 1.6%, (3): 2.4%, (4): 7.5% and (5): 17.8%. In the EACTS Congenital Heart Surgery Database, operations classified as STAT Mortality

  13. Initial application in the EACTS and STS Congenital Heart Surgery Databases of an empirically derived methodology of complexity adjustment to evaluate surgical case mix and results.

    PubMed

    Jacobs, Jeffrey Phillip; Jacobs, Marshall Lewis; Maruszewski, Bohdan; Lacour-Gayet, Francois G; Tchervenkov, Christo I; Tobota, Zdzislaw; Stellin, Giovanni; Kurosawa, Hiromi; Murakami, Arata; Gaynor, J William; Pasquali, Sara K; Clarke, David R; Austin, Erle H; Mavroudis, Constantine

    2012-11-01

    Outcomes evaluation is enhanced by assignment of operative procedures to appropriate categories based upon relative average risk. Formal risk modelling is challenging when a large number of operation types exist, including relatively rare procedures. Complexity stratification provides an alternative methodology. We report the initial application in the Congenital Heart Surgery Databases of the Society of Thoracic Surgeons (STS) and the European Association for Cardio-thoracic Surgery (EACTS) of an empirically derived system of complexity adjustment to evaluate surgical case mix and results. Complexity stratification is a method of analysis in which the data are divided into relatively homogeneous groups (called strata). A complexity stratification tool named the STS-EACTS Congenital Heart Surgery Mortality Categories (STAT Mortality Categories) was previously developed based on the analysis of 77,294 operations entered in the Congenital Heart Surgery Databases of EACTS (33,360 operations) and STS (43,934 patients). Procedure-specific mortality rate estimates were calculated using a Bayesian model that adjusted for small denominators. Operations were sorted by increasing risk and grouped into five categories (the STAT Mortality Categories) that were designed to minimize within-category variation and maximize between-category variation. We report here the initial application of this methodology in the EACTS Congenital Heart Surgery Database (47,187 operations performed over 4 years: 2006-09) and the STS Congenital Heart Surgery Database (64,307 operations performed over 4 years: 2006-09). In the STS Congenital Heart Surgery Database, operations classified as STAT Mortality Categories 1-5 were (1): 17332, (2): 20114, (3): 9494, (4): 14525 and (5): 2842. Discharge mortality was (1): 0.54%, (2): 1.6%, (3): 2.4%, (4): 7.5% and (5): 17.8%. In the EACTS Congenital Heart Surgery Database, operations classified as STAT Mortality Categories 1-5 were (1): 19874, (2): 12196, (3

  14. Change of electrical conductivities between hydrated and dehydrated samples of honeycomb sheet structures with mixed oxidation state paddlewheel dirhodium complexes and halide ions.

    PubMed

    Fuma, Yasuhiro; Miyashita, Osamu; Kawamura, Takashi; Ebihara, Masahiro

    2012-07-21

    A series of mixed oxidation state compounds, [{Rh(2)(acam)(4)}(3)(μ(3)-X)(2)]·nH(2)O (Hacam = acetamide; X = Cl, n = 4 (1·4H(2)O); X = Br, n = 10 (2·10H(2)O); X = I, n = 10 (3·10H(2)O)) and [{Rh(2)(pram)(4)}(3)(μ(3)-X)(2)]·6H(2)O (Hpram = propionamide; X = Cl (4·6H(2)O), Br (5·6H(2)O), I (6·6H(2)O)) were synthesized and their X-ray structures were determined. In the crystal structure of all of these complexes, dirhodium complexes and halide ions construct 2-D honeycomb sheet arrangements in which the walls consist of Rh(2) units and halide ions lie at the corners. Complexes 1·4H(2)O, 4·6H(2)O, 5·6H(2)O and 6·6H(2)O have three independent Rh(2) units, in which there are two Rh(2)(5+) and one Rh(2)(4+). In these structures, the water molecules hydrogen bond to O atoms and from the N atoms of the amidate ligands. The number of hydrogen bonds from water molecules to the Rh(2)(4+) unit is greater than that to the Rh(2)(5+) units. This suggests that there exists pinning of the oxidation states by water molecules. In the structures of 2·10H(2)O and 3·10H(2)O, all of the Rh(2) units are crystallographically equivalent. In these structures, eight of the 10 water molecules form a honeycomb-like network between the {Rh(2)(acam)(4)}(3)X(2) honeycomb sheets. The former four structures show very low electrical conductivities of ca. 10(-8) S cm(-1) (room temperature, pellets) and the latter structures have the higher values of ca. 10(-4) S cm(-1). In the former complexes, improvement of the values to 10(-6) S cm(-1) was observed, caused by loss of pinning water.

  15. Subsurface Connections and Magma Mixing as revealed by Olivine- and Pyroxene-Hosted Melt Inclusions from Cerro Negro Volcano and the Las Pilas-El Hoyo Complex, Nicaragua.

    NASA Astrophysics Data System (ADS)

    Venugopal, S.; Moune, S.; Williams-Jones, G.

    2015-12-01

    Cerro Negro, the youngest volcano in the Central American Volcanic Belt, is a polygenetic cinder cone with relatively frequent explosive basaltic eruptions. Las Pilas, on the other hand, is a much larger and older complex with milder and less frequent eruptions. Based on historical data, these two closely spaced volcanoes have shown concurrent eruptive behavior, suggesting a subsurface connection. To further investigate this link, melt inclusions, which are blebs of melt trapped in growing crystals, were the obvious choice for optimal comparison of sources and determination of pre-eruptive volatile contents and magmatic conditions. Olivine-hosted inclusions were chosen for both volcanoes and pyroxene-hosted inclusions were also sampled from Las Pilas to represent the evolved melt. Major, volatile and trace elements reveal a distinct geochemical continuum with Cerro Negro defining the primitive end member and Las Pilas representing the evolved end member. Volatile contents are high for Cerro Negro (up to 1260 ppm CO2, 4.27 wt% H2O and 1700 ppm S) suggesting that volatile exsolution is likely the trigger for Cerro Negro's explosive eruptions. Las Pilas volatile contents are lower but consistent with degassing and evolutionary trends shown by major oxides. Trace element contents are rather unique and suggest Cerro Negro magmas fractionally crystallize while Las Pilas magmas are the products of mixing. Magmatic conditions were estimated with major and volatile contents: at least 2.4 kbar and 1170 °C for Cerro Negro melts and 1.3 kbar and 1130 °C for Las Pilas melts with an overall oxygen fugacity at the NNO buffer. In combination with available literature data, this study suggests an interconnected subsurface plumbing system and thus Cerro Negro should be considered as the newest vent within the Las Pilas-El Hoyo Complex.

  16. Complex vertical layering and mixing of aerosols over the eastern Mediterranean: active and passive remote sensing at the Cyprus University of Technology

    NASA Astrophysics Data System (ADS)

    Mamouri, R.-E.; Nisantzi, A.; Hadjimitsis, D. G.; Ansmann, A.; Schwarz, A.; Basart, S.; Baldasano, J. M.

    2013-08-01

    Aerosols can have a complicated influence on climate conditions, directly as well as indirectly via cloud formation. The southeastern Mediterranean region can be characterized as a cross road of aerosols originating from European, Asian and African continents. Complex vertical aerosol distributions are frequently detected over Cyprus by means of active remote sensing. Observations of such complex aerosol layering and comparison of the measurements with aerosol products of regional and global atmospheric transport models are required to improve our understanding of life cycles of aerosol mixtures and their impact on climate as well as on satellite remote sensing products. In this study, a case of an intense desert dust outbreak from Syria and Saudi Arabia towards the eastern Mediterranean in September 2011 is presented. The observations used in this study were performed with a 532-nm polarization Lidar and a sun/sky AERONET photometer operated at 8 channels from 340 to 1640 nm wavelength. Both instruments belong to remote sensing station of the Cyprus Technical University at Limassol, Cyprus (34°N, 33°E). The lofted dust plume was doped with air masses that crossed sources of biomass burning smoke and anthropogenic pollution. In addition, the shallow marine boundary layer over the Mediterranean Sea and over Limassol became mixed with the anthropogenic haze by sea breeze circulations. The case study demonstrates the potential of combined lidar/photometer observations to deliver detailed vertically resolved information of the aerosol characteristics in terms of particle optical and microphysical properties, separately for the spherical particle fraction as well as for the non-spherical aerosol mode.

  17. Development of CdS Nanostructures by Thermal Decomposition of Aminocaproic Acid-Mixed Cd-Thiourea Complex Precursor: Structural, Optical and Photocatalytic Characterization.

    PubMed

    Patel, Jayesh D; Mighri, Frej; Ajji, Abdellah; Chaudhuri, Tapas K

    2015-04-01

    The present work deals with two different CdS nanostructures produced via hydrothermal and solvothermal decompositions of aminocaproic acid (ACA)-mixed Cd-thiourea complex precursor at 175 °C. Both nanostructures were extensively characterized for their structural, morphological and optical properties. The powder X-ray diffraction characterization showed that the two CdS nanostructures present a wurtzite morphology. Scanning electron microscopy and energy-dispersive X-ray characterizations revealed that the hydrothermal decomposition produced well-shaped CdS flowers composed of six dendritic petals, and the solvothermal decomposition produced CdS microspheres with close stoichiometric chemical composition. The UV-vis absorption and photoluminescence spectra of CdS dendritic flowers and microsphere nanostructures showed that both nanostructures present a broad absorption between 200 and 700 nm and exhibit strong green emissions at 576 and 520 nm upon excitations at 290 nm and 260 nm, respectively. The transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) characterizations confirmed that CdS microspheres were mesoporous and were composed of small nanocrystals. A possible growth mechanism in the formation of the CdS nanostructures was proposed based on morphology evolution as a function of the reaction time. Furthermore, the as-synthesized CdS nanostructures were found to exhibit highly efficient photocatalytic activities for the degradation of methyl orange (MeO) and rhodamine B (RhB) dyes.

  18. Synthesis Characterization and Biological Activities of Coordination Compounds of 4-Hydroxy-3-nitro-2H-chromen-2-one and Its Aminoethanoic Acid and Pyrrolidine-2-carboxylic Acid Mixed Ligand Complexes

    PubMed Central

    Akinkunmi, Ezekiel; Obuotor, Efere; Olawuni, Idowu; Isabirye, David; Jordaan, Johan

    2017-01-01

    Coordination compounds of 4-hydroxy-3-nitro-2H-chromen-2-one and their mixed ligand complexes with aminoethanoic acid and pyrrolidine-2-carboxylic acid were synthesized by the reaction of Cu(II) and Zn(II) salts in molar ratio 1 : 2 for the coumarin complexes and 1 : 1 : 1 for the mixed ligand complexes, in basic media. The compounds formed were characterized using infrared, Uv-vis spectrophotometric analyses, mass spectrometry, magnetic susceptibility measurements, and EDX analyses. It was concluded that 4-hydroxy-3-nitro-2H-chromen-2-one coordinated as a monobasic ligand for all the complexes; it also coordinated via the carbonyl moiety in the case of the Cu(II) mixed ligand complexes. Similarly it was proposed that the amino acids also coordinated in a bidentate fashion via their amino nitrogen and carboxylate oxygen atoms. The synthesized compounds were screened for their antimicrobial and cytotoxic activities. The complexes exhibited marginal antimicrobial activity but good cytotoxic activity. PMID:28270743

  19. Influence of extrinsic factors on electron transfer in a mixed-valence Fe(2+)/Fe(3+) complex: experimental results and theoretical considerations.

    PubMed

    Achim, C; Bominaar, E L; Staples, R J; Münck, E; Holm, R H

    2001-08-13

    The crystal structure of the mixed-valence complex (NEt(4))[Fe(2)(salmp)(2)].xMeCN(crystal) (x = 2,3) [1].xMeCN(crystal) was determined at temperatures between 153 and 293 K. The complex shows distinct Fe(2+) and Fe(3+) sites over this temperature interval. Variable temperature Mössbauer spectra confirm the valence-localized character of the complex. In contrast, spectroscopic investigation of powder samples generated from [1].xMeCN(crystal) indicate the presence of a valence-averaged component at temperatures above 150 K. To elucidate this apparent contradiction we have conducted a variable-temperature Mössbauer investigation of different forms of 1, including [1].xMeCN(crystal), [1].2DMF(crystal), [1].yMeCN(powder), and solution samples of 1 in acetonitrile. The low-temperature Mössbauer spectra of all forms are virtually identical and confirm the valence-localized nature of the S = (9)/(2) ground state. The high-temperature spectra reveal a subtle control of electron hopping by the environment of the complexes. Thus, [1].xMeCN(crystal) has valence-localized spectra at all explored temperatures, [1].2DMF(crystal) exhibits a complete collapse into a valence-averaged spectrum over a narrow temperature range, the powder exhibits partial valence averaging over a broad temperature interval, and the solution sample shows at 210 K the presence of a valence-averaged component in a minor proportion. The spectral transformations are characterized by a coexistence of valence-localized and valence-averaged spectral components. This phenomenon cannot be explained by intramolecular electron hopping between the valence-localized states Fe(A)(2+)Fe(B)(3+) and Fe(A)(3+)Fe(B)(2+) in a homogeneous ensemble of complexes, but requires relaxation processes involving at least three distinguishable states of the molecular anion. Hopping rates for [1].2DMF(crystal) and [1].yMeCN(powder) have been determined from spectral simulations, based on stochastic line shape theory. Analysis of

  20. Fluorescent mixed ligand copper(II) complexes of anthracene-appended Schiff bases: studies on DNA binding, nuclease activity and cytotoxicity.

    PubMed

    Jaividhya, Paramasivam; Ganeshpandian, Mani; Dhivya, Rajkumar; Akbarsha, Mohammad Abdulkadher; Palaniandavar, Mallayan

    2015-07-14

    A series of mixed ligand copper(ii) complexes of the type [Cu(L)(phen)(ACN)](ClO4)21-5, where L is a bidentate Schiff base ligand (N(1)-(anthracen-10-ylmethylene)-N(2)-methylethane-1,2-diamine (L1), N(1)-(anthracen-10-ylmethylene)-N(2),N(2)-dimethylethane-1,2-diamine (L2), N(1)-(anthracen-10-yl-methylene)-N(2)-ethylethane-1,2-diamine (L3), N(1)-(anthracen-10-ylmethylene)-N(2),N(2)-diethylethane-1,2-diamine (L4) and N(1)-(anthracen-10-ylmethylene)-N(3)-methylpropane-1,3-diamine (L5)) and phen is 1,10-phenanthroline, have been synthesized and characterized by spectral and analytical methods. The X-ray crystal structure of 5 reveals that the coordination geometry around Cu(ii) is square pyramidal distorted trigonal bipyramidal (τ, 0.76). The corners of the trigonal plane of the geometry are occupied by the N2 nitrogen atom of phen, the N4 nitrogen atom of L5 and the N5 nitrogen of acetonitrile while the N1 nitrogen of phen and the N3 nitrogen of L5 occupy the axial positions with an N1-Cu1-N3 bond angle of 176.0(3)°. All the complexes display a ligand field band (600-705 nm) and three less intense anthracene-based bands (345-395 nm) in solution. The Kb values calculated from absorption spectral titration of the complexes (π→π*, 250-265 nm) with Calf Thymus (CT) DNA vary in the order 5 > 4 > 3 > 2 > 1. The fluorescence intensity of the complexes (520-525 nm) decreases upon incremental addition of CT DNA, which reveals the involvement of phen rather than the appended anthracene ring in partial DNA intercalation with the DNA base stack. The extent of quenching is in agreement with the DNA binding affinities and the relative increase in the viscosity of DNA upon binding to the complexes as well. Thus 5 interacts with DNA more strongly than 4 on account of the stronger involvement in hydrophobic DNA interaction of the anthracenyl moiety, which is facilitated by the propylene ligand backbone with chair conformation. The ability of complexes (100 μM) to cleave DNA (p

  1. Mechanistic aspects of the chemistry of mononuclear Cr(III) complexes with pendant-arm macrocyclic ligands and formation of discrete Cr(III)/Fe(II) and Cr(III)/Fe(II)/Co(III) cyano-bridged mixed valence compounds.

    PubMed

    Basallote, Manuel G; Bernhardt, Paul V; Calvet, Teresa; Castillo, Carmen E; Font-Bardia, Mercè; Martínez, Manuel; Rodríguez, Carlos

    2009-11-21

    The kinetics and mechanism of the redox reaction between [Fe(II)(CN)(6)](4-) and the macrocyclic ligand complex [CrClL(15)](2+) (L(15) = 6-methyl-1,4,8,12-tetraazacyclopentadecane-6-amine) has been studied at different pH values. In acidic solution, the expected redox process occurs with no formation of any of the possible Cr(III)/Fe(II) mixed valence complexes, as those seen for the Co(III) species of the same family, due to the enhanced lability of the Cr(II) species formed on Fe(II) to Fe(III) oxidation. In alkaline conditions, the formation of the complex [Cr(L(15))(OH)(2)](+) takes place as an initial step that precedes a simple substitution process producing the expected cyano-bridged Cr(III)/Fe(II) complex. In this species the potentially pentadentate ligand, L(15), has a tetradentate coordination mode with a protonated exocyclic primary amine group and the redox potential is shifted to more negative values, thus disfavouring a redox driven reaction; the equivalent complex [CrCl(HL(14))(H(2)O)](3+) (L(14) = 6-methyl-1,4,8,11-tetraazacyclotetradecane-6-amine) has been prepared by the same method and characterized by X-ray crystallography. The final [Fe(II)(CN)(6)](4-) substituted complex, [{(HL(15))(OH)Cr(III)NC}Fe(II)(CN)(5)](-) shows pK(a) values of 3.8 and 7.4, as expected for the aqua and amino ligands, respectively. Its characterization indicated its Class II mixed valence character with a very intense MMCT band at 350 nm showing a much larger extinction coefficient than that observed for the Co(III) complexes of the same family. This fact is in good agreement with the much larger Cr(III)-Fe(II) (t(2g)-t(2g)) coupling through cyanide bridging ligands expected for these complexes. The fully mixed metal/valence/ligand trimetallic complex [{(HL(15))(OH)Cr(III)NC}{L(13)Co(III)NC}Fe(II)(CN)(4)](2+) has been prepared following the same procedures and the results are comparable. The final complex has the same Class II mixed valence character and its electronic

  2. The complex mixed Wentzel–Kramers–Brillouin-full-wave approach and its application to the two dimensional mode structure analysis of ion temperature gradient/collisionless trapped electron mode drift waves

    SciTech Connect

    Lu, Z. X.

    2015-05-15

    The complex mixed Wentzel–Kramers–Brillouin (WKB)-full-wave approach is applied to the 2D mode structure analysis of ion temperature gradient/collisionless trapped electron mode drift waves in tokamak plasmas. The parallel mode structure is calculated with the full-wave approach, while the radial envelope is calculated with the complex WKB method. The tilting of the global mode structure along radius is demonstrated analytically. The effects of the phase and amplitude variation of the radial envelope on the parallel mode structure are included in terms of a complex radial wave vector in the parallel mode equation. It is shown that the radial equilibrium non-uniformity leads to the asymmetry of the parallel mode structure not only in configuration space but also in spectrum space. The mixed approach provides a practical way to analyze the asymmetric component of the global mode structure due to radial equilibrium non-uniformity.

  3. SNP-Based QTL Mapping of 15 Complex Traits in Barley under Rain-Fed and Well-Watered Conditions by a Mixed Modeling Approach

    PubMed Central

    Mora, Freddy; Quitral, Yerko A.; Matus, Ivan; Russell, Joanne; Waugh, Robbie; del Pozo, Alejandro

    2016-01-01

    This study identified single nucleotide polymorphism (SNP) markers associated with 15 complex traits in a breeding population of barley (Hordeum vulgare L.) consisting of 137 recombinant chromosome substitution lines (RCSL), evaluated under contrasting water availability conditions in the Mediterranean climatic region of central Chile. Given that markers showed a very strong segregation distortion, a quantitative trait locus/loci (QTL) mapping mixed model was used to account for the heterogeneity in genetic relatedness between genotypes. Fifty-seven QTL were detected under rain-fed conditions, which accounted for 5–22% of the phenotypic variation. In full irrigation conditions, 84 SNPs were significantly associated with the traits studied, explaining 5–35% of phenotypic variation. Most of the QTL were co-localized on chromosomes 2H and 3H. Environment-specific genomic regions were detected for 12 of the 15 traits scored. Although most QTL-trait associations were environment and trait specific, some important and stable associations were also detected. In full irrigation conditions, a relatively major genomic region was found underlying hectoliter weight (HW), on chromosome 1H, which explained between 27% (SNP 2711-234) and 35% (SNP 1923-265) of the phenotypic variation. Interestingly, the locus 1923-265 was also detected for grain yield at both environmental conditions, accounting for 9 and 18%, in the rain-fed and irrigation conditions, respectively. Analysis of QTL in this breeding population identified significant genomic regions that can be used for marker-assisted selection (MAS) of barley in areas where drought is a significant constraint. PMID:27446139

  4. SNP-Based QTL Mapping of 15 Complex Traits in Barley under Rain-Fed and Well-Watered Conditions by a Mixed Modeling Approach.

    PubMed

    Mora, Freddy; Quitral, Yerko A; Matus, Ivan; Russell, Joanne; Waugh, Robbie; Del Pozo, Alejandro

    2016-01-01

    This study identified single nucleotide polymorphism (SNP) markers associated with 15 complex traits in a breeding population of barley (Hordeum vulgare L.) consisting of 137 recombinant chromosome substitution lines (RCSL), evaluated under contrasting water availability conditions in the Mediterranean climatic region of central Chile. Given that markers showed a very strong segregation distortion, a quantitative trait locus/loci (QTL) mapping mixed model was used to account for the heterogeneity in genetic relatedness between genotypes. Fifty-seven QTL were detected under rain-fed conditions, which accounted for 5-22% of the phenotypic variation. In full irrigation conditions, 84 SNPs were significantly associated with the traits studied, explaining 5-35% of phenotypic variation. Most of the QTL were co-localized on chromosomes 2H and 3H. Environment-specific genomic regions were detected for 12 of the 15 traits scored. Although most QTL-trait associations were environment and trait specific, some important and stable associations were also detected. In full irrigation conditions, a relatively major genomic region was found underlying hectoliter weight (HW), on chromosome 1H, which explained between 27% (SNP 2711-234) and 35% (SNP 1923-265) of the phenotypic variation. Interestingly, the locus 1923-265 was also detected for grain yield at both environmental conditions, accounting for 9 and 18%, in the rain-fed and irrigation conditions, respectively. Analysis of QTL in this breeding population identified significant genomic regions that can be used for marker-assisted selection (MAS) of barley in areas where drought is a significant constraint.

  5. Three-Level Mixed-Effects Logistic Regression Analysis Reveals Complex Epidemiology of Swine Rotaviruses in Diagnostic Samples from North America.

    PubMed

    Homwong, Nitipong; Diaz, Andres; Rossow, Stephanie; Ciarlet, Max; Marthaler, Douglas

    2016-01-01

    Rotaviruses (RV) are important causes of diarrhea in animals, especially in domestic animals. Of the 9 RV species, rotavirus A, B, and C (RVA, RVB, and RVC, respectively) had been established as important causes of diarrhea in pigs. The Minnesota Veterinary Diagnostic Laboratory receives swine stool samples from North America to determine the etiologic agents of disease. Between November 2009 and October 2011, 7,508 samples from pigs with diarrhea were submitted to determine if enteric pathogens, including RV, were present in the samples. All samples were tested for RVA, RVB, and RVC by real time RT-PCR. The majority of the samples (82%) were positive for RVA, RVB, and/or RVC. To better understand the risk factors associated with RV infections in swine diagnostic samples, three-level mixed-effects logistic regression models (3L-MLMs) were used to estimate associations among RV species, age, and geographical variability within the major swine production regions in North America. The conditional odds ratios (cORs) for RVA and RVB detection were lower for 1-3 day old pigs when compared to any other age group. However, the cOR of RVC detection in 1-3 day old pigs was significantly higher (p < 0.001) than pigs in the 4-20 days old and >55 day old age groups. Furthermore, pigs in the 21-55 day old age group had statistically higher cORs of RV co-detection compared to 1-3 day old pigs (p < 0.001). The 3L-MLMs indicated that RV status was more similar within states than among states or within each region. Our results indicated that 3L-MLMs are a powerful and adaptable tool to handle and analyze large-hierarchical datasets. In addition, our results indicated that, overall, swine RV epidemiology is complex, and RV species are associated with different age groups and vary by regions in North America.

  6. Crystal structure of a mixed-ligand silver(I) complex of the non-steroidal anti-inflammatory drug diclofenac and pyrimidine

    PubMed Central

    Hamamci Alisir, Sevim; Dege, Necmi

    2016-01-01

    In the title mixed-ligand silver(I) coordination polymeric complex with the non-steroidal anti-inflammatory drug diclofenac (C14H11Cl2NO2) (diclH) and pyrimidine (pym), namely poly[{μ2-2-[2-(2,6-di­chloro­anilino)phen­yl]acetato-κ2 O:O′}(μ2-pyrimidine-κ2 N 1:N 3)silver(I)], [Ag(C14H10Cl2NO2)(C4H4N2)]n or [Ag(μ-dicl)(μ-pym)]n, the very distorted tetra­hedral AgN2O2 coordination centres comprise two N-atom donors from bridging pym ligands [Ag—N = 2.381 (3) and 2.412 (3) Å] and two carboxyl­ate O-atom donors from dicl ligands [Ag—O = 2.279 (2) and 2.280 (2) Å], which bridge Ag atoms, giving a centrosymmetric dinuclear units with a short Ag⋯Ag separation [2.8931 (5) Å]. Within the units are short intra­ligand C—Cl⋯π(pym) inter­actions [3.6409 (15) Å]. The units are linked through the bridging N atoms of the pym ligand into a two-dimensional sheet–polymer structure lying parallel to (100) and stabilized by inter-ring π–π inter­actions between the pym ligands [Cg⋯Cg = 3.4199 (17) Å]. Additional inter-unit C—H⋯O and C—H⋯Cg hydrogen-bonding inter­actions between the sheets give an overall three-dimensional structure. PMID:27746945

  7. Feasibility of Applied Gaming During Interdisciplinary Rehabilitation for Patients With Complex Chronic Pain and Fatigue Complaints: A Mixed-Methods Study.

    PubMed

    Vugts, Miel A P; Joosen, Margot C W; van Bergen, Alfonsus H M M; Vrijhoef, Hubertus J M

    2016-04-01

    Applied gaming holds potential as a convenient and engaging means for the delivery of behavioral interventions. For developing and evaluating feasible computer-based interventions, policy makers and designers rely on limited knowledge about what causes variation in usage. In this study, we looked closely at why and by whom an applied game (LAKA) is demanded and whether it is feasible (with respect to acceptability, demand, practicality, implementation, and efficacy) and devised a complementary intervention during an interdisciplinary rehabilitation program (IRP) for patients with complex chronic pain and fatigue complaints. A mixed-methods design was used. Quantitative process analyses and assessments of feasibility were carried out with patients of a Dutch rehabilitation center who received access to LAKA without professional support during a 16-week interdisciplinary outpatient program. The quantitative data included records of routinely collected baseline variables (t0), additional surveys to measure technology acceptance before (t1) and after 8 weeks of access to LAKA (t2), and automatic log files of usage behavior (frequency, length, and progress). Subsequently, semistructured interviews were held with purposively selected patients. Interview codes triangulated and illustrated explanations of usage and supplemented quantitative findings on other feasibility domains. Of the 410 eligible patients who started an IRP during the study period, 116 patients participated in additional data collections (108 with problematic fatigue and 47 with moderate or severe pain). Qualitative data verified that hedonic motivation was the most important factor for behavioral intentions to use LAKA (P<.001). Moreover, quotes illustrated a positive association between usage intentions (t1) and baseline level (t0) coping by active engagement (Spearman ρ=0.25; P=.008) and why patients who often respond by seeking social support were represented in a group of 71 patients who accessed

  8. Strategies for efficiently selecting PHA producing mixed microbial cultures using complex feedstocks: Feast and famine regime and uncoupled carbon and nitrogen availabilities.

    PubMed

    Oliveira, Catarina S S; Silva, Carlos E; Carvalho, Gilda; Reis, Maria A

    2017-07-25

    Production of polyhydroxyalkanoates (PHAs) by open mixed microbial cultures (MMCs) has been attracting increasing interest as an alternative technology to PHA production by pure cultures, due to the potential for lower costs associated with the use of open systems (eliminating the requirement for sterile conditions) and the utilisation of cheap feedstock (industrial and agricultural wastes). Such technology relies on the efficient selection of an MMC enriched in PHA-accumulating organisms. Fermented cheese whey, a protein-rich complex feedstock, has been used previously to produce PHA using the feast and famine regime for selection of PHA accumulating cultures. While this selection strategy was found efficient when operated at relatively low organic loading rate (OLR, 2g-CODL(-1)d(-1)), great instability and low selection efficiency of PHA accumulating organisms were observed when higher OLR (ca. 6g-CODL(-1)d(-1)) was applied. High organic loading is desirable as a means to enhance PHA productivity. In the present study, a new selection strategy was tested with the aim of improving selection for high OLR. It was based on uncoupling carbon and nitrogen supply and was implemented and compared with the conventional feast and famine strategy. For this, two selection reactors were fed with fermented cheese whey applying an OLR of ca. 8.5g-CODL(-1) (with 3.8g-CODL(-1) resulting from organic acids and ethanol), and operated in parallel under similar conditions, except for the timing of nitrogen supplementation. Whereas in the conventional strategy nitrogen and carbon substrates were added simultaneously at the beginning of the cycle, in the uncoupled substrates strategy, nitrogen addition was delayed to the end of the feast phase (i.e. after exogenous carbon was exhausted). The two different strategies selected different PHA-storing microbial communities, dominated by Corynebacterium and a Xantomonadaceae, respectively with the conventional and the new approaches. The new

  9. Feasibility of Applied Gaming During Interdisciplinary Rehabilitation for Patients With Complex Chronic Pain and Fatigue Complaints: A Mixed-Methods Study

    PubMed Central

    Joosen, Margot C W; van Bergen, Alfonsus H M M; Vrijhoef, Hubertus J M

    2016-01-01

    Background Applied gaming holds potential as a convenient and engaging means for the delivery of behavioral interventions. For developing and evaluating feasible computer-based interventions, policy makers and designers rely on limited knowledge about what causes variation in usage. Objective In this study, we looked closely at why and by whom an applied game (LAKA) is demanded and whether it is feasible (with respect to acceptability, demand, practicality, implementation, and efficacy) and devised a complementary intervention during an interdisciplinary rehabilitation program (IRP) for patients with complex chronic pain and fatigue complaints. Methods A mixed-methods design was used. Quantitative process analyses and assessments of feasibility were carried out with patients of a Dutch rehabilitation center who received access to LAKA without professional support during a 16-week interdisciplinary outpatient program. The quantitative data included records of routinely collected baseline variables (t0), additional surveys to measure technology acceptance before (t1) and after 8 weeks of access to LAKA (t2), and automatic log files of usage behavior (frequency, length, and progress). Subsequently, semistructured interviews were held with purposively selected patients. Interview codes triangulated and illustrated explanations of usage and supplemented quantitative findings on other feasibility domains. Results Of the 410 eligible patients who started an IRP during the study period, 116 patients participated in additional data collections (108 with problematic fatigue and 47 with moderate or severe pain). Qualitative data verified that hedonic motivation was the most important factor for behavioral intentions to use LAKA (P<.001). Moreover, quotes illustrated a positive association between usage intentions (t1) and baseline level (t0) coping by active engagement (Spearman ρ=0.25; P=.008) and why patients who often respond by seeking social support were represented in

  10. Vibrational energy relaxation of a hydrogen-bonded complex dissolved in a polar liquid via the mixed quantum-classical Liouville method.

    PubMed

    Hanna, Gabriel; Geva, Eitan

    2008-04-03

    The vibrational energy relaxation (VER) of the hydrogen stretch in a linear hydrogen-bonded complex dissolved in a polar solvent is studied. The study is based on the Azzouz-Borgis model [Azzouz, H.; Borgis, D. J. Chem. Phys. 1993, 98, 7361], which is known to account for many important features of real hydrogen-bonded systems, including ionic-to-covalent tautomerism and a broad distribution of hydrogen stretch frequencies. A description of VER in this strongly coupled system is considered, which consists of the following three consecutive steps: (1) solvation on the adiabatic excited vibrational surface; (2) nonadiabatic transition from the excited to the ground adiabatic vibrational surface; and (3) solvation on the adiabatic ground vibrational surface. The relaxation dynamics during those three steps were simulated via the mixed quantum-classical Liouville method, where the hydrogen is treated quantum-mechanically, while the other particles are treated in a classical-like manner. The solvation on the excited-state surface was found to occur rapidly ( approximately 0.5 ps) and to involve energy exchange with both the intramolecular and intermolecular degrees of freedom. It was also found that, while energy is released to the solvent during the solvation of the covalent tautomer, the solvation of the ionic tautomer involves absorption of energy from the solvent. The decrease in the transition frequency during the solvation process also facilitates the nonadiabatic transitions, which occur rapidly ( approximately 0.8 ps) thereafter. The nonadiabatic transitions were shown to be induced by interactions with a large number of solvent molecules and to be relatively insensitive to their location relative to the complex. Finally, solvation on the ground-state surface was seen to occur on a time scale of approximately 1.0 ps and leads to nonequilibrium ionic and covalent subpopulations. Equilibration on the ground-state surface occurs on a significantly slower time scale

  11. Spectroscopic studies of oxo-centered, carboxylate-bridged, trinuclear mixed-valence iron (ІІІ, ІІІ, ІІ) complexes with aromatic hydroxycarboxylic acids

    NASA Astrophysics Data System (ADS)

    Singh, Atresh Kumar; Singh, Alok Kumar

    2013-08-01

    New type of oxo-centered, carboxylate-bridged, trinuclear, mixed-valence iron complexes of the general formula [Fe3O(OOCR)3(OOCR*)3L3] (where R = C13H27 or C15H31 and R* = C6H4(OH), (R'); C6H5CH(OH), (R″) or (C6H5)2C(OH), (R) and L = Methanol) were synthesized by the reaction of [Fe3O(OOCCH3)6(H2O)3] with straight chain carboxylic acids and aromatic hydroxycarboxylic acids. These were characterized by elemental analyses, spectral (electronic, infrared, Mössbauer, FAB mass and powder XRD) studies, conductance and magnetic susceptibility measurements. Infrared spectra suggested bidentate and bridging mode of coordination of both the carboxylate and hydroxycarboxylate anions along with Fe3O vibrations in the complexes. Mössbauer parameters indicated the presence of high-spin Fe(ІІ) (S = 2) and high-spin Fe(ІІІ) (S = 5/2) centers in the complexes, confirming the valence-localized type of species. An intervalence-transfer band observed at 13,690-13,850 cm-1 range in the room-temperature electronic spectra of the complexes also suggested the complexes containing iron in mixed-valence state. Trinuclear nature of the complexes was confirmed by their FAB mass spectra. Magnetic moment values displayed octahedral geometry around each iron in the complexes and a net anti-ferromagnetic exchange coupling via μ-oxo atom related to mixed-valence pairs. A plausible structure for these complexes has been established on the basis of spectra and magnetic moment data.

  12. Sylgard® Mixing Study

    SciTech Connect

    Bello, Mollie; Welch, Cynthia F.; Goodwin, Lynne Alese; Keller, Jennie

    2014-08-22

    Sylgard® 184 and Sylgard® 186 silicone elastomers form Dow Corning® are used as potting agents across the Nuclear Weapons Complex. A standardized mixing procedure is required for filled versions of these products. The present study is a follow-up to a mixing study performed by MST-7 which established the best mixing procedure to use when adding filler to either 184 or 186 base resins. The most effective and consistent method of mixing resin and curing agent for three modified silicone elastomer recipes is outlined in this report. For each recipe, sample size, mixing type, and mixing time was varied over 10 separate runs. The results show that the THINKY™ Mixer gives reliable mixing over varying batch sizes and mixing times. Hand Mixing can give improved mixing, as indicated by reduced initial viscosity; however, this method is not consistent.

  13. Synthesis and characterization of mono and mixed ligand, Ni(II), Pd(II) and Pt(II) complexes of S-5-phenyl-1, 3, 4-oxadiazole-2-yl benzothioate with some tertiary diphosphines ligands

    NASA Astrophysics Data System (ADS)

    Saleh, R. A.; Mohammad, H. A.; Gerber, T. I.; Hosten, E. C.

    2017-09-01

    Mixed ligand transition metal Ni(II), Pd(II) and Pt(II)) complexes containing two sorts of ligands: S-5-phenyl-1,3,4-oxadiazole-2-yl benzothioate (phozbt) and terteiary diphosphines, have been prepared. Ni(II) complex have a tetrahedral geometry and all Pd and Pt complexes are square planer geometry. The diphosphines ligands act as a bidentate chelates that bonded to metal center (Ni, Pd and Pt) through both phosphorous atoms. On the other hand (phozbt) ligand bound to Ni(II) metal via carbonyl oxygen atom, while in palladium and platinum complexes it was bound at oxadiazole sulfur atom. The prepared ligand and complexes were characterized on the basis of FT-IR, 1H, 31P and 13C -NMR spectra as well as molar conductivity, magnetic susceptibility measurements, UV-visible and X-ray diffraction.

  14. Synthesis, structural characterization, thermal and electrochemical studies of mixed ligand Cu(II) complexes containing 2-phenyl-3-(benzylamino)-1,2-dihydroquinazoline-4-(3H)-one and bidentate N-donor ligands.

    PubMed

    Sawant, V A; Yamgar, B A; Sawant, S K; Chavan, S S

    2009-12-01

    Some mixed ligand Cu(II) complexes of the type [Cu(L)(en)X(2)] (1a-3a), [Cu(L)(en)](ClO(4))(2) (4a), [Cu(L)(phen)X(2)] (1b-3b) and [Cu(L)(phen)](ClO(4))(2) (4b) [where L = 2-phenyl-3-(benzylamino)-1,2-dihydroquinazoline-4-(3H)-one; en = ethylenediamine; phen = 1,10-phenanthroline; X = Cl(-), N(3)(-) and NCS(-)] have been prepared. The complexes were characterized on the basis of elemental analysis, molar conductance, magnetic moment, IR, UV-vis, mass, ESR and thermal studies. On the basis of electronic spectral data and magnetic susceptibility measurement octahedral geometry has been proposed for 1a-3a and 1b-3b and square-planer geometry for 4a and 4b. The ESR spectral data of complexes provided information about their structure on the basis of Hamiltonian parameters and degree of covalency. The electrochemical behaviour of mixed ligand Cu(II) complexes was studied which showed that complexes of phen appear at more positive potential as compared to those for corresponding en complexes.

  15. Mixed ligand complex formation of 2-aminobenzamide with Cu(II) in the presence of some amino acids: synthesis, structural, biological, pH-metric, spectrophotometric and thermodynamic studies.

    PubMed

    Dharmaraja, Jeyaprakash; Esakkidurai, Thirugnanasamy; Subbaraj, Paramasivam; Shobana, Sutha

    2013-10-01

    Mixed ligand Cu(II) complexes of 2-aminobenzamide (2AB) and amino acids viz., glycine (gly), L-alanine (ala), L-valine (val) and L-phenylalanine (phe) have been synthesised and characterized by various physico-chemical and spectral techniques. The calculated g-tensor values for Cu(II) complexes at 77 K and 300 K, show the distorted octahedral geometry which has been confirmed from the absorption studies. Consequently, the thermal studies illustrate that the loss of water and acetate molecules in the initial stage which are followed by the decomposition of organic residues. The powder X-ray diffraction and SEM analysis reflect that all the complexes have well-defined crystallinity nature with homogeneous morphology. The binding activities of CT DNA with CuAB complexes have been examined by absorption studies. Further, the oxidative cleavage interactions of 2-aminobenzamide and CuAB complexes with DNA were studied by gel electrophoresis method in H2O2 medium. Also, the complex formation of Cu(II) involving 2-aminobenzamide and amino acids were carried out by a combined pH-metric and spectrophotometric techniques in 50% (v/v) water-ethanol mixture at 300, 310, 320 and 330±0.1 K with I=0.15 mol dm(-3) (NaClO4). In solution, CuAB and CuAB2 species has been detected and the binding modes of 2-aminobenzamide and amino acids in both binary and mixed ligand complexes are same. The calculated stabilization value of ΔlogK, log X and log X' indicates higher stabilities for the mixed ligand complexes rather than their binary species. The thermodynamic parameters like ΔG, ΔH and ΔS have been determined from temperature dependence of the stability constant. In vitro biological activities of 2-aminobenzamide, CuA and CuAB complexes show remarkable activities against some bacterial and fungal strains. The percentage distribution of various binary and mixed ligand species in solution at dissimilar pH intervals were also evaluated. Copyright © 2013 Elsevier B.V. All rights

  16. Mixed ligand complex formation of 2-aminobenzamide with Cu(II) in the presence of some amino acids: Synthesis, structural, biological, pH-metric, spectrophotometric and thermodynamic studies

    NASA Astrophysics Data System (ADS)

    Dharmaraja, Jeyaprakash; Esakkidurai, Thirugnanasamy; Subbaraj, Paramasivam; Shobana, Sutha

    2013-10-01

    Mixed ligand Cu(II) complexes of 2-aminobenzamide (2AB) and amino acids viz., glycine (gly), L-alanine (ala), L-valine (val) and L-phenylalanine (phe) have been synthesised and characterized by various physico-chemical and spectral techniques. The calculated g-tensor values for Cu(II) complexes at 77 K and 300 K, show the distorted octahedral geometry which has been confirmed from the absorption studies. Consequently, the thermal studies illustrate that the loss of water and acetate molecules in the initial stage which are followed by the decomposition of organic residues. The powder X-ray diffraction and SEM analysis reflect that all the complexes have well-defined crystallinity nature with homogeneous morphology. The binding activities of CT DNA with CuAB complexes have been examined by absorption studies. Further, the oxidative cleavage interactions of 2-aminobenzamide and CuAB complexes with DNA were studied by gel electrophoresis method in H2O2 medium. Also, the complex formation of Cu(II) involving 2-aminobenzamide and amino acids were carried out by a combined pH-metric and spectrophotometric techniques in 50% (v/v) water-ethanol mixture at 300, 310, 320 and 330 ± 0.1 K with I = 0.15 mol dm-3 (NaClO4). In solution, CuAB and CuAB2 species has been detected and the binding modes of 2-aminobenzamide and amino acids in both binary and mixed ligand complexes are same. The calculated stabilization value of Δ log K, log X and log X' indicates higher stabilities for the mixed ligand complexes rather than their binary species. The thermodynamic parameters like ΔG, ΔH and ΔS have been determined from temperature dependence of the stability constant. In vitro biological activities of 2-aminobenzamide, CuA and CuAB complexes show remarkable activities against some bacterial and fungal strains. The percentage distribution of various binary and mixed ligand species in solution at dissimilar pH intervals were also evaluated.

  17. Deconstructing the complexity of substance use among young men who have sex with men (YMSM) by optimizing the role of qualitative strategies in a mixed methods study

    PubMed Central

    Kubicek, Katrina; Weiss, George; Iverson, Ellen F.; Kipke, Michele D.

    2010-01-01

    Qualitative data can be a powerful tool in developing interventions for substance use and other HIV-risk behaviors. Mixed-methods design offers researchers the ability to obtain data that provides both breadth and depth to their research. However, the integration of qualitative data in mixed-methods research has been limited. This paper describes the qualitative design of the Healthy Young Men’s Study, a longitudinal mixed-method study with an ethnically diverse cohort of young men who have sex with men (YMSM) (N=526) in Los Angeles. Integral to this discussion is how a mixed-methods study can address common challenges such as sampling, representation and integration. PMID:20222783

  18. The roles of fractional crystallization, magma mixing, crystal mush remobilization and volatile-melt interactions in the genesis of a young basalt-peralkaline rhyolite suite, the greater Olkaria volcanic complex, Kenya Rift valley

    USGS Publications Warehouse

    Macdonald, R.; Belkin, H.E.; Fitton, J.G.; Rogers, N.W.; Nejbert, K.; Tindle, A.G.; Marshall, A.S.

    2008-01-01

    The Greater Olkaria Volcanic Complex is a young (???20 ka) multi-centred lava and dome field dominated by the eruption of peralkaline rhyolites. Basaltic and trachytic magmas have been erupted peripherally to the complex and also form, with mugearites and benmoreites, an extensive suite of magmatic inclusions in the rhyolites. The eruptive rocks commonly represent mixed magmas and the magmatic inclusions are themselves two-, three- or four-component mixes. All rock types may carry xenocrysts of alkali feldspar, and less commonly plagioclase, derived from magma mixing and by remobilization of crystal mushes and/or plutonic rocks. Xenoliths in the range gabbro-syenite are common in the lavas and magmatic inclusions, the more salic varieties sometimes containing silicic glass representing partial melts and ranging in composition from anorthite ?? corundum- to acmite-normative. The peralkaline varieties are broadly similar, in major element terms, to the eruptive peralkaline rhyolites. The basalt-trachyte suite formed by a combination of fractional crystallization, magma mixing and resorption of earlier-formed crystals. Matrix glass in metaluminous trachytes has a peralkaline rhyolitic composition, indicating that the eruptive rhyolites may have formed by fractional crystallization of trachyte. Anomalous trace element enrichments (e.g. ??? 2000 ppm Y in a benmoreite) and negative Ce anomalies may have resulted from various Na- and K-enriched fluids evolving from melts of intermediate composition and either being lost from the system or enriched in other parts of the reservoirs. A small group of nepheline-normative, usually peralkaline, magmatic inclusions was formed by fluid transfer between peralkaline rhyolitic and benmoreitic magmas. The plumbing system of the complex consists of several independent reservoirs and conduits, repeatedly recharged by batches of mafic magma, with ubiquitous magma mixing. ?? The Author 2008. Published by Oxford University Press. All

  19. Environmental Assessment and Finding of No Significant Impact: Interim Measures for the Mixed Waste Management Facility Groundwater at the Burial Ground Complex at the Savannah River Site

    SciTech Connect

    N /A

    1999-12-08

    The U. S. Department of Energy (DOE) prepared this environmental assessment (EA) to analyze the potential environmental impacts associated with the proposed interim measures for the Mixed Waste Management Facility (MW) groundwater at the Burial Ground Complex (BGC) at the Savannah River Site (SRS), located near Aiken, South Carolina. DOE proposes to install a small metal sheet pile dam to impound water around and over the BGC groundwater seepline. In addition, a drip irrigation system would be installed. Interim measures will also address the reduction of volatile organic compounds (VOCS) from ''hot-spot'' regions associated with the Southwest Plume Area (SWPA). This action is taken as an interim measure for the MWMF in cooperation with the South Carolina Department of Health and Environmental Control (SCDHEC) to reduce the amount of tritium seeping from the BGC southwest groundwater plume. The proposed action of this EA is being planned and would be implemented concurrent with a groundwater corrective action program under the Resource Conservation and Recovery Act (RCRA). On September 30, 1999, SCDHEC issued a modification to the SRS RCRA Part B permit that adds corrective action requirements for four plumes that are currently emanating from the BGC. One of those plumes is the southwest plume. The RCRA permit requires SRS to submit a corrective action plan (CAP) for the southwest plume by March 2000. The permit requires that the initial phase of the CAP prescribe a remedy that achieves a 70-percent reduction in the annual amount of tritium being released from the southwest plume area to Fourmile Branch, a nearby stream. Approval and actual implementation of the corrective measure in that CAP may take several years. As an interim measure, the actions described in this EA would manage the release of tritium from the southwest plume area until the final actions under the CAP can be implemented. This proposed action is expected to reduce the release of tritium from

  20. Three-Level Mixed-Effects Logistic Regression Analysis Reveals Complex Epidemiology of Swine Rotaviruses in Diagnostic Samples from North America

    PubMed Central

    Diaz, Andres; Rossow, Stephanie; Ciarlet, Max; Marthaler, Douglas

    2016-01-01

    Rotaviruses (RV) are important causes of diarrhea in animals, especially in domestic animals. Of the 9 RV species, rotavirus A, B, and C (RVA, RVB, and RVC, respectively) had been established as important causes of diarrhea in pigs. The Minnesota Veterinary Diagnostic Laboratory receives swine stool samples from North America to determine the etiologic agents of disease. Between November 2009 and October 2011, 7,508 samples from pigs with diarrhea were submitted to determine if enteric pathogens, including RV, were present in the samples. All samples were tested for RVA, RVB, and RVC by real time RT-PCR. The majority of the samples (82%) were positive for RVA, RVB, and/or RVC. To better understand the risk factors associated with RV infections in swine diagnostic samples, three-level mixed-effects logistic regression models (3L-MLMs) were used to estimate associations among RV species, age, and geographical variability within the major swine production regions in North America. The conditional odds ratios (cORs) for RVA and RVB detection were lower for 1–3 day old pigs when compared to any other age group. However, the cOR of RVC detection in 1–3 day old pigs was significantly higher (p < 0.001) than pigs in the 4–20 days old and >55 day old age groups. Furthermore, pigs in the 21–55 day old age group had statistically higher cORs of RV co-detection compared to 1–3 day old pigs (p < 0.001). The 3L-MLMs indicated that RV status was more similar within states than among states or within each region. Our results indicated that 3L-MLMs are a powerful and adaptable tool to handle and analyze large-hierarchical datasets. In addition, our results indicated that, overall, swine RV epidemiology is complex, and RV species are associated with different age groups and vary by regions in North America. PMID:27145176

  1. Thermo-chemical fluxes, reactions and mixing in hydrothermal plumes at Oceanic Core complexes (Mid-Atlantic Ridge, 13°30'N and 13°20'N)

    NASA Astrophysics Data System (ADS)

    Destrigneville, C.; Chavagnac, V.; Olive, J. A. L.; Leleu, T.; Rommevaux, C.; Escartin, J.; Jamieson, J. W.; Petersen, S.

    2015-12-01

    Large-offset detachment faults are widespread along the slow-spreading Mid-Atlantic Ridge (MAR), exhume ultramafic rocks, and host a great diversity of hydrothermal systems. During the ODEMAR'13 cruise, the fully developed 13º20'N and 13º30'N oceanic core complexes (OCC) along MAR were investigated to constrain the tectonic, hydrothermal and magmatic processes enabling detachment formation. Here we focus on the composition and fluxes of hydrothermal fluids discharging out of these OCCs. ROV Victor6000 dives confirmed the occurrence of active discharge near the breakaway side of the 13º30'N OCC (Semenov-2), and observed high-temperature venting on the striated fault surface of the 13º20'N OCC (Irinovskoe). Black smoker fluids and hydrothermal plume waters (2-110ºC) were collected using gas-tight titanium syringes and in-situ pumping fluid samplers mounted on the ROV, respectively. The Semenov-2 fluids (3 vent sites at 317ºC) are characterized by lower chlorinity than seawater (Cl = 525 mmol/l) and extremely low metal concentrations (Fe, Mn, Cu, Zn < ~20 μmol/l). By contrast, the Irinovskoe fluids (2 vent sites at 364ºC) exhibit higher chlorinity than seawater at Cl = 605 mmol/l, high Fe and Mn concentrations, and yet low metal concentrations. Temperature and concentration of conservative species were also measured along the centerlines of selected plumes within the first ~3 m above the vents. These measurements were inverted to constrain vent heat and mass fluxes using a plume entrainment model, yielding for individual plumes values of ~1-95 MW and 1-60 10-3 m3/s, respectively. We use these to calculate annual filterable iron fluxes at both sites of the 13º20'N OCC of 2.6 - 3.9 106 mol/yr, which are 4 orders of magnitude higher than those calculated for the 13º30'N OCC. We estimate, however, that ~94% of this Fe flux is lost through precipitation when rising hydrothermal fluids mix with entrained seawater.

  2. Transferrin, is a mixed chelate-protein ternary complex involved in the mechanism of iron uptake by serum-transferrin in vitro?

    PubMed

    Pakdaman, R; Abdallah, F B; El Hage Chahine, J M

    1999-11-12

    Iron uptake by transferrin from triacetohydroxamatoFe(III) (Fe(AHA)3) in the presence of bicarbonate has been investigated between pH 7 and 8.2. The protein transits from the opened apo- to the closed holoform by several steps with the accumulation of at least three kinetic intermediates. All these steps are accompanied by proton losses, probably occurring from the protein ligands and the side-chains involved in the interdomain H-bonding nets. The minor bihydroxamatoFe(III) species Fe(AHA)2 exchanges its iron with the C-site of apotransferrin in interaction with bicarbonate without detectable formation of any intermediate protein-iron-ligand mixed complex; direct second-order rate constant k1=4.15(+/-0.05)x10(7) M(-1) s(-1). The kinetic product loses a single proton and undergoes a modification in its conformation followed by the loss of two or three protons; first-order rate constant k2=3.25(+/-0.15) s(-1). This induces a new modification in the conformation; first-order rate constant k3=5.90(+/-0.30)x10(-2) s(-1). This new modification in conformation rate controls iron uptake by the N-site of the protein and is followed by a single proton loss; K3a=6.80 nM. Finally, the holoprotein or the monoferric transferrin in its thermodynamic equilibrated state is produced by a last modification in the conformation occurring in about 4000 seconds. But for the Fe(AHA)3 dissociation and the involvement of Fe(AHA)2 in the first step of iron uptake, this mechanism is identical to that reported for iron uptake from FeNAc3. This implies that the exchange of iron between a chelate and serum-transferrin occurs by a single general mechanism. The nature of the iron-providing chelate is only important for the first kinetic step of the exchange, which can be slowed to such an extent that it rate limits the exchange of iron. Copyright 1999 Academic Press.

  3. Magma mixing, crustal contamination, contamination before chemical analysis or complex history? The case study from the Wołek Hill, SW Poland

    NASA Astrophysics Data System (ADS)

    Nowak, Monika

    2015-04-01

    Wołek Hill is one of the smallest exposures from ca. 300 occurrences of Cenozoic volcanic rocks from SW Poland. The outcrop is located about 100 km SW from Wrocław and belongs to the Złotoryja Volcanic Field, which is one of the largest volcanic fields in the Polish part of the Central European Volcanic Province (Ladenberger et al. 2006). The volcanic body, which is about 20 m wide, cross-cuts older Permian volcanic rocks (trachyandesites and rhyolites) and is well exposed in an old abandoned quarry. The occurrence was studied in detail because of great amount of mantle and crustal xenoliths brought to the surface by magma. Wołek Hill is one of the two occurrences in SW Poland where amphibole crystals were recognized as results of modal metasomatism in lithospheric mantle (Nowak et al. 2012). The volcanic rock from Wołek Hill represents complex history, difficult to explain by simple model. The rock was classified as basanite (Nowak, 2012). Its texture is porphyritic to glomeroporphyritic, olivine (Ol) and clinopyroxene (Cpx) occurs as phenocrysts, Cpx is also the dominant phase in the groundmass. Wołek Hill basanite differs from other exposures in Złotoryja Volcanic Field by presence of xenocrysts of Ol and Cpx from mantle rocks and also quartz (Qrtz) and feldspars (Feld) xenocrysts from crustal rocks. Those xenocrysts with additional carbonate veins, probably related with post-volcanic processes, were a great difficulty during rock preparation for whole-rock and isotopic analyses. The complex history of Wołek Hill basanite is visible in its chemical content (slight increase of SiO2, positive Pb anomaly, 87Sr/86Sr and 143Nd/144Nd values), but also in its petrography (e.g. by three types of olivine phenocrysts Fo82-91 with differences in zonation patterns reflecting Fo content; the most abundant are phenocrysts with normal zoning, but also crystals with opposite zoning and oscillatory zoning were recognised). According to available data from the basanite

  4. Photodamage of a Mn(III/IV)-oxo mixed-valence compound and photosystem II: evidence that a high-valent manganese species is responsible for UV-induced photodamage of the oxygen-evolving complex in photosystem II.

    PubMed

    Wei, Zi; Cady, Clyde W; Brudvig, Gary W; Hou, Harvey J M

    2011-01-01

    The Mn cluster in photosystem II (PS II) is believed to play an important role in the UV photoinhibition of green plants, but the mechanism is still not clear at a molecular level. In this work, the photochemical stability of [Mn(III)(O)(2)Mn(IV)(H(2)O)(2)(Terpy)(2)](NO(3))(3) (Terpy=2,2':6',2''-terpyridine), designated as Mn-oxo mixed-valence dimer, a well characterized functional model of the oxygen-evolving complex in PS II, was examined in aqueous solution by exposing the complex to excess light irradiation at six different wavelengths in the range of 250 to 700 nm. The photodamage of the Mn-oxo mixed-valence dimer was confirmed by the decrease of its oxygen-evolution activity measured in the presence of the chemical oxidant oxone. Ultraviolet light irradiation induced a new absorption peak at around 400-440 nm of the Mn-oxo mixed-valence dimer. Visible light did not have the same effect on the Mn-oxo mixed-valence dimer. We speculate that the spectral change may be caused by conversion of the Mn(III)O(2)Mn(IV) dimer into a new structure--Mn(IV)O(2)Mn(IV). In the processes, the appearance of a 514 nm fluorescence peak was observed in the solution and may be linked to the hydration or protonation of Terpy ligand in the Mn-oxo dimer. In comparing the response of the PS II functional model compound and the PS II complex to excess light radiation, our results support the idea that UV photoinhibition is triggered at the Mn(4)Ca center of the oxygen-evolution complex in PS II by forming a modified structure, possibly a Mn(IV) species, and that the reaction of Mn ions is likely the initial step.

  5. Analysis of the excitation profiles of Raman bands of linear-chain mixed-valence complexes. The geometry of [Pt(en) 2][Pt(en) 2Br 2]Br 4 in the intervalence state

    NASA Astrophysics Data System (ADS)

    Clark, Robin J. H.; Dines, Trevor J.

    1991-10-01

    Calculations of the resonance Raman excitation profiles for the ν 1 band and its overtones have been performed for the linear- chain mixed-valence platinum complex [Pt(en) 2Br 2]Br 4. It is found that the Pt IV length increases by 0.075 Å in the intervalence state. A satisfactory fit to the excitation profiles requires the inclusion of a second excited state at 16500 cm -1, which we have assigned to Br→Pt IV charge transfer.

  6. Mixed-mode acrylamide-based continuous beds bearing tert-butyl groups for capillary electrochromatography synthesized via complexation of N-tert-butylacrylamide with a water-soluble cyclodextrin. Part I: Retention properties.

    PubMed

    Al-Massaedh, Ayat Allah; Pyell, Ute

    2016-12-16

    With the aim to improve the understanding of morphology and efficiency properties, we investigate in this series the impact of the complex formation constant of the hydrophobic monomer with respect to statistically methylated-β-cyclodextrin (Me-β-CD) on the electrochromatographic properties of highly crosslinked amphiphilic mixed-mode acrylamide-based monolithic stationary phases. Based on our previous work on amphiphilic mixed-mode monolithic stationary phases for capillary electrochromatography (CEC) using N-(1-adamantyl)acrylamide (Ad-AAm) as hydrophobic monomer that forms an extremely strong water-soluble inclusion complex with Me-β-CD, we now selected N-tert-butylacrylamide (NTBA) as hydrophobic monomer forming an inclusion complex with Me-β-CD with a much lower value of the formation constant. Mixed-mode monolithic stationary phases are synthesized by in-situ free radical copolymerization of cyclodextrin-solubilized N-tert-butylacrylamide, a water soluble crosslinker (piperazinediacrylamide), a hydrophilic neutral monomer (methacrylamide), and a negatively charged monomer (vinylsulfonic acid) in aqueous medium in bind silane pre-treated fused silica capillaries. The synthesized monolithic stationary phases have both hydrophobic and hydrophilic moieties and can be employed in the reversed-phase mode, in the normal-phase mode, in a mixed-mode or in the hydrophilic interaction liquid chromatography (HILIC) mode (depending on the composition of the mobile phase and on the properties of the solute). Morphology and retention properties of this new type of stationary phase are compared to those reported in our previous series. With a homologues series of alkylphenones it is confirmed that the hydrophobicity (methylene selectivity αmeth) of the stationary phase is strongly dependent on the type of hydrophobic monomer employed. The studies reveal a significant influence of the formation constant of the involved host-guest inclusion complex on the morphology (i

  7. 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

  8. Mixed cryoglobulinemia

    PubMed Central

    Ferri, Clodoveo

    2008-01-01

    Mixed cryoglobulinemia (MC), type II and type III, refers to the presence of circulating cryoprecipitable immune complexes in the serum and manifests clinically by a classical triad of purpura, weakness and arthralgias. It is considered to be a rare disorder, but its true prevalence remains unknown. The disease is more common in Southern Europe than in Northern Europe or Northern America. The prevalence of 'essential' MC is reported as approximately 1:100,000 (with a female-to-male ratio 3:1), but this term is now used to refer to a minority of MC patients only. MC is characterized by variable organ involvement including skin lesions (orthostatic purpura, ulcers), chronic hepatitis, membranoproliferative glomerulonephritis, peripheral neuropathy, diffuse vasculitis, and, less frequently, interstitial lung involvement and endocrine disorders. Some patients may develop lymphatic and hepatic malignancies, usually as a late complication. MC may be associated with numerous infectious or immunological diseases. When isolated, MC may represent a distinct disease, the so-called 'essential' MC. The etiopathogenesis of MC is not completely understood. Hepatitis C virus (HCV) infection is suggested to play a causative role, with the contribution of genetic and/or environmental factors. Moreover, MC may be associated with other infectious agents or immunological disorders, such as human immunodeficiency virus (HIV) infection or primary Sjögren's syndrome. Diagnosis is based on clinical and laboratory findings. Circulating mixed cryoglobulins, low C4 levels and orthostatic skin purpura are the hallmarks of the disease. Leukocytoclastic vasculitis involving medium- and, more often, small-sized blood vessels is the typical pathological finding, easily detectable by means of skin biopsy of recent vasculitic lesions. Differential diagnoses include a wide range of systemic, infectious and neoplastic disorders, mainly autoimmune hepatitis, Sjögren's syndrome, polyarthritis, and B

  9. Mixed cryoglobulinemia.

    PubMed

    Ferri, Clodoveo

    2008-09-16

    Mixed cryoglobulinemia (MC), type II and type III, refers to the presence of circulating cryoprecipitable immune complexes in the serum and manifests clinically by a classical triad of purpura, weakness and arthralgias. It is considered to be a rare disorder, but its true prevalence remains unknown. The disease is more common in Southern Europe than in Northern Europe or Northern America. The prevalence of 'essential' MC is reported as approximately 1:100,000 (with a female-to-male ratio 3:1), but this term is now used to refer to a minority of MC patients only. MC is characterized by variable organ involvement including skin lesions (orthostatic purpura, ulcers), chronic hepatitis, membranoproliferative glomerulonephritis, peripheral neuropathy, diffuse vasculitis, and, less frequently, interstitial lung involvement and endocrine disorders. Some patients may develop lymphatic and hepatic malignancies, usually as a late complication. MC may be associated with numerous infectious or immunological diseases. When isolated, MC may represent a distinct disease, the so-called 'essential' MC. The etiopathogenesis of MC is not completely understood. Hepatitis C virus (HCV) infection is suggested to play a causative role, with the contribution of genetic and/or environmental factors. Moreover, MC may be associated with other infectious agents or immunological disorders, such as human immunodeficiency virus (HIV) infection or primary Sjögren's syndrome. Diagnosis is based on clinical and laboratory findings. Circulating mixed cryoglobulins, low C4 levels and orthostatic skin purpura are the hallmarks of the disease. Leukocytoclastic vasculitis involving medium- and, more often, small-sized blood vessels is the typical pathological finding, easily detectable by means of skin biopsy of recent vasculitic lesions. Differential diagnoses include a wide range of systemic, infectious and neoplastic disorders, mainly autoimmune hepatitis, Sjögren's syndrome, polyarthritis, and B

  10. Immunolocalization of the smooth muscle-specific protein calponin in complex and mixed tumors of the mammary gland of the dog: assessment of the morphogenetic role of the myoepithelium.

    PubMed

    Espinosa Los de Monteros, A; Millán, M Y; Ordás, J; Carrasco, L; Reymundo, C; Martín Las de Mulas, J

    2002-03-01

    The immunohistochemical expression of the smooth muscle-specific protein calponin was studied to assess the contribution of myoepithelial cells to the histogenesis of spindle cells of complex and mixed tumors of the mammary gland of the dog and the origin of cartilage and bone in mixed tumors. Formalin-fixed tissues from 55 benign and malignant tumors (49 also containing surrounding normal mammary gland) were evaluated. Periacinar and periductal myoepithelial cells of all the 49 normal mammary glands were diffusely stained by the anti-human calponin monoclonal antibody. Calponin was found in 53 (98%) of the tumors studied, reacting with the myoepithelium-like cells of 86% of benign tumors and their remnants in 85% of malignant tumors. Five different types of calponin-immunoreactive myoepithelial cells were identified: hypertrophic myoepithelial cells. fusiform cells, stellate myoepithelial cells, rounded (myoepithelial) cells, and chondroblasts. Differences in staining intensity and staining pattern among these five types of cells suggested a transition of myoepithelial cells to chondroblasts. Stromal myofibroblasts also showed calponin immunoreactivity, but they did not react with a cytokeratin 14 monoclonal antibody, which recognizes myoepithelial cells in mammary gland. Calponin appears to be a very sensitive marker of normal and neoplastic myoepithelium in the canine mammary gland, and its identification in different cell types of complex and mixed tumors of the mammary gland of the dog suggests a major histogenetic role for myoepithelial cells.

  11. Fluorescence and electron paramagnetic resonance studies of norfloxacin and N-donor mixed-ligand ternary copper(II) complexes: Stability and interaction with SDS micelles.

    PubMed

    Vignoli Muniz, Gabriel S; Incio, Jimmy Llontop; Alves, Odivaldo C; Krambrock, Klaus; Teixeira, Letícia R; Louro, Sonia R W

    2017-08-05

    The stability of ternary copper(II) complexes of a heterocyclic ligand, L (L being 2,2'-bipyridine (bipy) or 1,10-phenanthroline (phen)) and the fluorescent antibacterial agent norfloxacin (NFX) as the second ligand was studied at pH7.4 and different ionic strengths. Fluorescence quenching upon titration of NFX with the binary complexes allowed to obtain stability constants for NFX binding, Kb, as a function of ionic strength. The Kb values vary by more than two orders of magnitude when buffer concentration varies from 0.5 to 100mM. It was observed that previously synthesized ternary complexes dissociate in buffer according with the obtained stability constants. This shows that equimolar solutions of NFX and binary complexes are equivalent to solutions of synthesized ternary complexes. The interaction of the ternary copper complexes with anionic SDS (sodium dodecyl sulfate) micelles was studied by fluorescence and electron paramagnetic resonance (EPR). Titration of NFX-loaded SDS micelles with the complexes Cu:L allowed to determine the stability constants inside the micelles. Fluorescence quenching demonstrated that SDS micelles increase the stability constants by factors around 50. EPR spectra gave details of the copper(II) local environment, and demonstrated that the structure of the ternary complexes inside SDS micelles is different from that in buffer. Mononuclear ternary complexes formed inside the micelles, while in buffer most ternary complexes are binuclear. The results show that anionic membrane interfaces increase formation of copper fluoroquinolone complexes, which can influence bioavailability, membrane diffusion, and mechanism of action of the antibiotics. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Reactivity of phosphonodithioato-dppt Ni(II) mixed ligand complexes with halogens: first example of a metal-coordinating tribromide anion.

    PubMed

    Aragoni, M Carla; Arca, Massimiliano; Coles, Susanne L; Devillanova, Francesco A; Hursthouse, Michael B; Isaia, Francesco; Lippolis, Vito

    2012-06-14

    The first example of a metal complex containing a tribromide anion is presented and characterised by X-ray diffraction. Hybrid DFT calculations were used to investigate the nature of the bond in coordinating trihalides and the differences with the corresponding mono-halide complexes.

  13. Synthesis, structure and reactivity of Pd and Ir complexes based on new lutidine-derived NHC/phosphine mixed pincer ligands.

    PubMed

    Sánchez, Práxedes; Hernández-Juárez, Martín; Álvarez, Eleuterio; Paneque, Margarita; Rendón, Nuria; Suárez, Andrés

    2016-11-14

    Coordination studies of new lutidine-derived hybrid NHC/phosphine ligands (CNP) to Pd and Ir have been performed. Treatment of the square-planar [Pd(CNP)Cl](AgCl2) complex 2a with KHMDS produces the selective deprotonation at the CH2P arm of the pincer to yield the pyridine-dearomatised complex 3a. A series of cationic [Ir(CNP)(cod)](+) complexes 4 has been prepared by reaction of the imidazolium salts 1 with Ir(acac)(cod). These derivatives exhibit in the solid state, and in solution, a distorted trigonal bipyramidal structure in which the CNP ligands adopt an unusual C(axial)-N(equatorial)-P(equatorial) coordination mode. Reactions of complexes 4 with CO and H2 yield the carbonyl species 5a(Cl) and 6a(Cl), and the dihydrido derivatives 7, respectively. Furthermore, upon reaction of complex 4b(Br) with base, selective deprotonation at the methylene CH2P arms is observed. The, thus formed, deprotonated Ir complex 8b reacts with H2 in a ligand-assisted process leading to the trihydrido complex 9b, which can also be obtained by reaction of 7b(Cl) with H2 in the presence of KO(t)Bu. Finally, the catalytic activity of Ir-CNP complexes in the hydrogenation of ketones has been briefly assessed.

  14. Synthesis, characterization, X-ray crystal structure, DFT calculation, DNA binding, and antimicrobial assays of two new mixed-ligand copper(II) complexes

    NASA Astrophysics Data System (ADS)

    Ebrahimipour, S. Yousef; Sheikhshoaie, Iran; Mohamadi, Maryam; Suarez, Sebastian; Baggio, Ricardo; Khaleghi, Moj; Torkzadeh-Mahani, Masoud; Mostafavi, Ali

    2015-05-01

    Two new Cu(II) complexes, [Cu(L)(phen)] (1), [Cu(L)(bipy)] (2), where L2- = (3-methoxy-2oxidobenzylidene)benzohydrazidato, phen = 1,10 phenanthroline, and bipy = 2,2‧ bipyridine, were prepared and fully characterized using elemental analyses, FT-IR, molar conductivity, and electronic spectra. The structures of both complexes were also determined by X-ray diffraction. It was found that, both complexes possessed square pyramidal coordination environment in which, Cu(II) ions were coordinated by donor atoms of HL and two nitrogens of heterocyclic bases. Computational studies were performed using DFT calculations at B3LYP/6-311+G(d,p) level of theory. DNA binding activities of these complexes were also investigated using electronic absorption, competitive fluorescence titration and cyclic voltammetry studies. The obtained results indicated that binding of the complexes to DNA was of intercalative mode. Furthermore, antimicrobial activities of these compounds were screened against microorganisms.

  15. Interaction of DNA with Simple and Mixed Ligand Copper(II) Complexes of 1,10-Phenanthrolines as Studied by DNA-Fiber EPR Spectroscopy

    PubMed Central

    Chikira, Makoto; Ng, Chew Hee; Palaniandavar, Mallayan

    2015-01-01

    The interaction of simple and ternary Cu(II) complexes of 1,10-phenanthrolines with DNA has been studied extensively because of their various interesting and important functions such as DNA cleavage activity, cytotoxicity towards cancer cells, and DNA based asymmetric catalysis. Such functions are closely related to the DNA binding modes of the complexes such as intercalation, groove binding, and electrostatic surface binding. A variety of spectroscopic methods have been used to study the DNA binding mode of the Cu(II) complexes. Of all these methods, DNA-fiber electron paramagnetic resonance (EPR) spectroscopy affords unique information on the DNA binding structures of the complexes. In this review we summarize the results of our DNA-fiber EPR studies on the DNA binding structure of the complexes and discuss them together with the data accumulated by using other measurements. PMID:26402668

  16. Mixed-ligand cobalt(II) complexes of bioinorganic and medicinal relevance, involving dehydroacetic acid and β-diketones: Their synthesis, hyphenated experimental-DFT, thermal and bactericidal facets

    NASA Astrophysics Data System (ADS)

    Maurya, R. C.; Malik, B. A.; Mir, J. M.; Vishwakarma, P. K.; Rajak, D. K.; Jain, N.

    2015-11-01

    The present report pertains to synthesis and combined experimental-DFT studies of a series of four novel mixed-ligand complexes of cobalt(II) of the general composition [Co(dha)(L)(H2O)2], where dhaH = dehydroacetic acid, LH = β-ketoenolates viz., o-acetoacetotoluidide (o-aatdH), o-acetoacetanisidide (o-aansH), acetylacetone (acacH) or 1-benzoylacetone (1-bac). The resulting complexes were formulated based on elemental analysis, molar conductance, magnetic measurements, mass spectrometric, IR, electronic, electron spin resonance and cyclic voltammetric studies. The TGA based thermal behavior of one representative complex was evaluated. Molecular geometry optimizations and vibrational frequency calculations have been performed with Gaussian 09 software package by using density functional theory (DFT) methods with B3LYP/LANL2MB combination for dhaH and one of its complexes, [Co(dha)(1-bac)(H2O)2]. Theoretical data has been found in an excellent agreement with the experimental results. Based on experimental and theoretical data, suitable trans-octahedral structure has been proposed for the present class of complexes. Moreover, the complexes also showed a satisfactory antibacterial activity.

  17. Synthesis, structure information, DNA/BSA binding affinity and in vitro cytotoxic studies of mixed ligand copper(II) complexes containing a phenylalanine derivative and diimine co-ligands.

    PubMed

    Annaraj, B; Balakrishnan, C; Neelakantan, M A

    2016-07-01

    Binary [Cu(PAIC)(H2O)2]·H2O (1) and mixed ligand [Cu(PAIC)(L)]·2H2O complexes, where PAIC=phenylalanine imidazole carboxylic acid, L=diimine coligands [2,2'-bipyridine (bpy) (2) and 1,10-phenanthroline (phen) (3)] have been synthesized and fully characterized by analytical and spectral techniques. The X-ray structure of [Cu(PAIC)(phen)]·2H2O (3) shows a N4O coordination with square pyramidal geometry around the copper (II) atom. The spin Hamiltonian parameters calculated for the complexes account for the distorted square planar structure and rules out the possibility of a trigonal bipyramidal structure. Interaction of the complexes (1-3) with calf thymus DNA (CT DNA) was studied by using different techniques (absorption titration, fluorescence quenching and thermal melting) and the studies suggest that these complexes bind to CT DNA through intercalation. The DNA-binding affinity of the complexes has further been explained by DFT computational results. Binding activity of Bovine serum albumin (BSA) reveals that the complexes can strongly quench the intrinsic fluorescence of BSA through a static quenching mechanism. DNA cleavage experiments using plasmid DNA pUC 19 show that the complexes exhibit efficient chemical nuclease activity even in the absence of any external additives. The cytotoxicity of the complexes against human normal cell line (HBL 100) and human breast cancer cell line (MCF-7) shows that metal complexation of the ligands results in a significant enhancement in the cell death of MCF-7. Finally, docking studies on DNA and protein binding interactions were performed.

  18. Synthesis and Evaluation of In Vitro DNA/Protein Binding Affinity, Antimicrobial, Antioxidant and Antitumor Activity of Mononuclear Ru(II) Mixed Polypyridyl Complexes.

    PubMed

    Putta, Venkat Reddy; Chintakuntla, Nagamani; Mallepally, Rajender Reddy; Avudoddi, Srishailam; K, Nagasuryaprasad; Nancherla, Deepika; V V N, Yaswanth; R S, Prakasham; Surya, Satyanarayana Singh; Sirasani, Satyanarayana

    2016-01-01

    The four novel Ru(II) complexes [Ru(phen)2MAFIP](2+) (1) [MAFIP = 2-(5-(methylacetate)furan-2-yl)-1 H-imidazo[4,5-f] [1, 10]phenanthroline, phen = 1,10-Phenanthroline], [Ru(bpy)2MAFIP](2+) (2) (bpy = 2,2'-bipyridine) and [Ru(dmb)2MAFIP](2+) (3) (dmb = 4,4'-dimethyl-2,2'-bipyridine) and [Ru(hdpa)2MAFIP](2+) (4) (hdpa = 2,2-dipyridylamine) have been synthesized and fully characterized via elemental analysis, NMR spectroscopy, EI-MS and FT-IR spectroscopy. In addition, the DNA-binding behaviors of the complexes 1-4 with calf thymus DNA were investigated by UV-Vis absorption, fluorescence studies and viscosity measurement. The DNA-binding experiments showed that the complexes 1-4 interact with CT-DNA through an intercalative mode. BSA protein binding affinity of synthesized complexes was determined by UV/Vis absorption and fluorescence emission titrations. The binding affinity of ruthenium complexes was supported by molecular docking. The photoactivated cleavage of plasmid pBR322 DNA by ruthenium complexes 1-4 was investigated. All the synthesized compounds were tested for antimicrobial activity by using three Gram-negative (Escherichia coli, Salmonella typhi and Pseudomonas aeruginosa) and three Gram-positive (Micrococcus luteus, Bacillus subtilis and Bacillus megaterium) organisms, these results indicated that complex 3 was more activity compared to other complexes against all tested microbial strains while moderate antimicrobial activity profile was noticed for complex 4. The antioxidant activity experiments show that the complexes exhibit moderate antioxidant activity. The cytotoxicity of synthesized complexes on HeLa cell lines has been examined by MTT assay. The apoptosis assay was carried out with Acridine Orange (AO) staining methods and the results indicate that complexes can induce the apoptosis of HeLa cells. The cell cycle arrest investigated by flow cytometry and these results indicate that complexes 1-4 induce the cell cycle arrest at G0/G1

  19. Synergistic interaction between a mixed ligand copper (II) chelate complex and two anticancer agents in T47D human breast cancer cells in vitro.

    PubMed

    Geromichalos, G D; Trafalis, D T; Katsoulos, G A; Papageorgiou, A; Dalezis, P; Triandafillidis, E B; Hadjikostas, C C; Athanassiou, A

    2006-01-01

    We have developed a copper(II) chelate complex with a tridentate ONN-Schiff ligand and the anion of salicylate, showing a potent cytotoxic activity against a panel of human and murine cancer cell lines. In this experiment we have explored the combination effect between Cu(SalNEt(2))salicylate (Cu-Sal) complex and two widely used drugs in cancer chemotherapy, bleomycin (BLM) and 5-fluorouracil (5-FU), against T47D human breast cancer cells. Previous theoretical quantum-chemical studies of this complex and ass adducts with biological molecules elucidated the underlying mechanism of action of this complex. Cells grown in adherence in 96-well microplates were exposed simultaneously to both agents for 48 h. During cytotoxicity was assessed via the XTT colorimetric assay. The combined drug interaction was assessed with the median-effect analysis and the combination index (CI). Concurrent treatment of cells with Cu-Sal complex and the chemotherapeutic drugs BLM and 5-FU and the antioxidant agent ascorbic acid (AsA) resulted mainly in synergistic interaction for most concentration ratios. Cu-Sal complex interacts synergistically with the chemotherapeutic drugs for most schedules of administration. These findings call for prompting to search for possible interaction of this complex with other cellular elements of fundamental importance in cell proliferation.

  20. Metal Dependence of Signal Transmission through Molecular Quantum-Dot Cellular Automata (QCA): A Theoretical Study on Fe, Ru, and Os Mixed-Valence Complexes

    PubMed Central

    Tokunaga, Ken

    2010-01-01

    Dynamic behavior of signal transmission through metal complexes [L5M-BL-ML5]5+ (M=Fe, Ru, Os, BL=pyrazine (py), 4,4’-bipyridine (bpy), L=NH3), which are simplified models of the molecular quantum-dot cellular automata (molecular QCA), is discussed from the viewpoint of one-electron theory, density functional theory. It is found that for py complexes, the signal transmission time (tst) is Fe(0.6 fs) < Os(0.7 fs) < Ru(1.1 fs) and the signal amplitude (A) is Fe(0.05 e) < Os(0.06 e) < Ru(0.10 e). For bpy complexes, tst and A are Fe(1.4 fs) < Os(1.7 fs) < Ru(2.5 fs) and Os(0.11 e) < Ru(0.12 e) < Fe(0.13 e), respectively. Bpy complexes generally have stronger signal amplitude, but waste longer time for signal transmission than py complexes. Among all complexes, Fe complex with bpy BL shows the best result. These results are discussed from overlap integral and energy gap of molecular orbitals.

  1. Synthesis and characterization of mixed-ligand diimine-piperonal thiosemicarbazone complexes of ruthenium(II): Biophysical investigations and biological evaluation as anticancer and antibacterial agents

    NASA Astrophysics Data System (ADS)

    Beckford, Floyd A.; Thessing, Jeffrey; Shaloski, Michael, Jr.; Canisius Mbarushimana, P.; Brock, Alyssa; Didion, Jacob; Woods, Jason; Gonzalez-Sarrías, Antonio; Seeram, Navindra P.

    2011-04-01

    We have used a novel microwave-assisted method developed in our laboratories to synthesize a series of ruthenium-thiosemicarbazone complexes. The new thiosemicarbazone ligands are derived from benzo[ d][1,3]dioxole-5-carbaldehyde (piperonal) and the complexes are formulated as [(diimine) 2Ru(TSC)](PF 6) 2 (where the TSC is the bidentate thiosemicarbazone ligand). The diimine in the complexes is either 2,2'-bipyridine or 1,10-phenanthroline. The complexes have been characterized by spectroscopic means (NMR, IR and UV-Vis) as well as by elemental analysis. We have studied the biophysical characteristics of the complexes by investigating their anti-oxidant ability as well as their ability to disrupt the function of the human topoisomerase II enzyme. The complexes are moderately strong binders of DNA with binding constants of 10 4 M -1. They are also strong binders of human serum albumin having binding constants on the order of 10 4 M -1. The complexes show good in vitro anticancer activity against human colon cancer cells, Caco-2 and HCT-116 and indeed show some cytotoxic selectivity for cancer cells. The IC 50 values range from 7 to 159 μM (after 72 h drug incubation). They also have antibacterial activity against Gram-positive strains of pathogenic bacteria with IC 50 values as low as 10 μM; little activity was seen against Gram-negative strains. It has been established that all the compounds are catalytic inhibitors of human topoisomerase II.

  2. Simulating Ru L 3 -Edge X-ray Absorption Spectroscopy with Time-Dependent Density Functional Theory: Model Complexes and Electron Localization in Mixed-Valence Metal Dimers

    SciTech Connect

    Van Kuiken, Benjamin E.; Valiev, Marat; Daifuku, Stephanie L.; Bannan, Caitlin; Strader, Matthew L.; Cho, Hana; Huse, Nils; Schoenlein, Robert W.; Govind, Niranjan; Khalil, Munira

    2013-05-30

    Ruthenium L3-edge X-ray absorption (XA) spectroscopy probes unoccupied 4d orbitals of the metal atom and is increasingly being used to investigate the local electronic structure in ground and excited electronic states of Ru complexes. The simultaneous development of computational tools for simulating Ru L3-edge spectra is crucial for interpreting the spectral features at a molecular level. This study demonstrates that time-dependent density functional theory (TDDFT) is a viable and predictive tool for simulating ruthenium L3-edge XA spectroscopy. We systematically investigate the effects of exchange correlation functional and implicit and explicit solvent interactions on a series of RuII and RuIII complexes in their ground and electronic excited states. The TDDFT simulations reproduce all of the experimentally observed features in Ru L3-edge XA spectra within the experimental resolution (0.4 eV). Our simulations identify ligand-specific charge transfer features in complicated Ru L3-edge spectra of [Ru(CN)6]4- and RuII polypyridyl complexes illustrating the advantage of using TDDFT in complex systems. We conclude that the B3LYP functional most accurately predicts the transition energies of charge transfer features in these systems. We use our TDDFT approach to simulate experimental Ru L3-edge XA spectra of transition metal mixed-valence dimers of the form [(NC)5MII-CN-RuIII(NH3)5] (where M = Fe or Ru) dissolved in water. Our study determines the spectral signatures of electron delocalization in Ru L3-edge XA spectra. We find that the inclusion of explicit solvent molecules is necessary for reproducing the spectral features and the experimentally determined valencies in these mixed-valence complexes. This study validates the use of TDDFT for simulating Ru 2p excitations using popular quantum chemistry codes and providing a powerful interpretive tool for equilibrium and ultrafast Ru L3-edge XA spectroscopy.

  3. In vitro DNA and BSA-binding, cell imaging and anticancer activity against human carcinoma cell lines of mixed ligand copper(II) complexes.

    PubMed

    Anjomshoa, Marzieh; Torkzadeh-Mahani, Masoud

    2015-01-01

    Binding studies of two water soluble copper(II) complexes of the type [Cu(phen-dion)(diimine)Cl]Cl, where phen-dione is 1,10-phenanthroline-5,6-dione and diimine is 1,10-phenanthroline (1) and 2,2'-bipyridine (2), with fish sperm DNA (FS-DNA) and bovine serum albumin (BSA) have been examined under physiological conditions by a series of experimental methods (UV-Vis absorption, fluorescence, viscosity, cyclic voltammetry (CV) and circular dichroism (CD) spectroscopic techniques). The experimental results indicate that the complexes interact with FS-DNA by electrostatic and partial insertion of pyridyl rings between the base stacks of double-stranded DNA. The complexes could quench the intrinsic fluorescence of BSA with the binding constants (Kbin) of 32×10(5) M(-1) (1) and 1.7×10(5) M(-1) (2) at 290 K. The quenching mechanism, thermodynamic parameters, the number of binding sites and the effect of the Cu(II) complexes on the secondary structure of BSA have been explored. The in vitro anticancer chemotherapeutic potential of two copper(II) complexes against the three human carcinoma cell lines (MCF-7, A-549, and HT-29) and one normal cell line (DPSC) were evaluated by MTT assay. The results of in vitro cytotoxicity indicate that the complex (1) has greater cytotoxicity activity against all of the cell lines, especially HT-29 with IC50 values of 1.8 μM. Based on the IC50 values, these complexes did not display an apparent cyto-selective profile, because it would appear that two complexes are toxic to all four model cell lines. The microscopic analyses of the cancer cells confirm results of cytotoxicity. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Synergistic interaction between a novel mixed ligand copper(II) chelate complex and a panel of anticancer agents in T47D human breast cancer cells in vitro.

    PubMed

    Geromichalos, G D; Katsoulos, G A; Trafalis, D T; Hadjikostas, C C; Papageorgiou, A

    2005-01-01

    We have developed a novel copper(II) chelate complex with a tridentate ONN-Schiff base ligand and the anion of salicylate, which presented a potent cytotoxic activity against a panel of human and murine cancer cell lines. In this experiment we explored the combined effect between Cu(SalNEt(2))salicylate (Cu-Sal) complex and the widely used anticancer drugs carboplatin (CBDCA), cyclophosphamide (CTX) and paclitaxel (TXL) against T47D human breast cancer cells. Theoretical (quantum-chemical) study of this complex and its adducts with biological molecules were carried out, aiming at the elucidation of the underlying mechanism of action. Cells grown in adherence in 96-well microplates were exposed simultaneously to both agents for 48 h. Drug cytotoxicity was assessed via the XTT colorimetric assay. The combined drug interaction was assessed with the median-effect analysis and the combination index (CI). Copper(II) salicylate complex was proved active against T47D human breast cancer cells. Concurrent treatment of cells with Cu-Sal complex and the chemotherapeutic drugs CBDCA, CTX and TXL, mainly showed a synergistic interaction in most concentration ratios. Cu-Sal complex interacts synergistically with tested chemotherapeutic drugs for most schedules of administration, and only occasionally an additive or antagonistic effect was apparent. With the aid of quantum-chemical calculations it was demonstrated that the mechanism of action of this complex involves binding to DNA and RNA. These findings prompt to search for possible interaction of this complex with other cellular elements of fundamental importance in cell proliferation.

  5. Potentiometric study of binary complexes of 3-[(1 R)-1-hydroxy-2-(methylamino)ethyl]phenol hydrochloride with some lanthanide ions in aqueous and mixed solutions

    NASA Astrophysics Data System (ADS)

    Sharma, S. S.; Kadia, M. V.

    2014-12-01

    The complexation of lanthanide ions (Y3+, La3+, Ce3+, Pr3+, Nd3+, Sm3+, Gd3+, Tb3+, and Dy3+) with 3-[(1 R)-1-hydroxy-2-(methylamino)ethyl]phenol hydrochloride was studied at different temperatures and different ionic strengths in aqueous solutions by Irving-Rossotti pH titration technique. Stepwise calculation, PKAS and BEST Fortran IV computer programs were used for determination of proton-ligand and metal-ligand stability constants. The formation of species like MA, MA2, and MA(OH) is considered in SPEPLOT. Thermodynamic parameters of complex formation (Δ G, Δ H, and Δ S) are also evaluated. Negative Δ G and Δ H values indicate that complex formation is favourable in these experimental conditions. The stability of complexes is also studied at in different solvent-aqueous (vol/vol). The stability series of lanthanide complexes has shown to have the "gadolinium break." Stability of complexes decreases with increase in ionic strength and temperature. Effect of systematic errors like effect of dissolved carbon dioxide, concentration of alkali, concentration of acid, concentration of ligand and concentration of metal have also been explained.

  6. Photoluminescent mixed ligand complexes of CuX (X = Cl, Br, I) with PPh3 and a polydentate imino-pyridyl ligand - Syntheses, structural variations and catalytic property

    NASA Astrophysics Data System (ADS)

    Ghorai, Anupam; Mondal, Jahangir; Patra, Goutam K.

    2015-10-01

    Three ternary copper(I) complexes [CuI2Cl2(L1)(PPh3)4] (1), [CuI2Br2(L1) (PPh3)4] (2) and [CuI2(μ-I)2 (μ-L1) (PPh3)2]n (3) have been prepared by reactions of CuX (X = Cl, Br and I) with PPh3 and the polydentate imino-pyridyl ligand L1. These complexes have been characterized by elemental analysis, IR, UV-Vis, NMR and X-ray crystallography. From single crystal structural analysis it has been found that complexes 1 and 2 are homo-dinuclear having non-bridging halide ions whereas complex 3 is a 1-D zig-zag co-ordination polymer containing bridged iodide ions. Complexes 1, 2 and 3 are photoluminescent at room temperature in chloroform whereas ligand L1 is non-emissive. The E½ values of the CuIsbnd CuII couple of 1, 2 and 3 are 0.98 V, 0.92 V and 0.42 V respectively (vs Ag/AgCl in 1 M KCl, scan rate 100 mV s-1). All three complexes function as effective catalysts for the synthesis of 2-substituted benzoxazoles.

  7. Bisamidate and Mixed Amine/Amidate NiN2S2 Complexes as Models for Nickel-Containing Acetyl Coenzyme A Synthase and Superoxide Dismutase: An Experimental and Computational Study

    PubMed Central

    Mathrubootham, Vaidyanathan; Thomas, Jason; Staples, Richard; McCraken, John; Shearer, Jason; Hegg, Eric L.

    2010-01-01

    The distal nickel site of acetyl-CoA synthase (Nid-ACS) and reduced nickel superoxide dismutase (Ni-SOD) display similar square-planar NiIIN2S2 coordination environments. One difference between these two sites, however, is that the nickel ion in Ni-SOD contains a mixed amine/amidate coordination motif while the Nid site in Ni-ACS contains a bisamidate coordination motif. To provide insight into the consequences of the different coordination environments on the properties of the Ni ions, we systematically examined two square-planar NiIIN2S2 complexes, one with bisthiolate-bisamidate ligation (Et4N)2(Ni(L1))·2H2O (2) [H4L1 = N-(2-mercaptoacetyl)-N’-(2-mercaptoethyl)glycinamide] and another with bisthiolate-amine/amidate ligation K(Ni(HL2)) (3) [H4L2 = N-(2“-mercaptoethyl)-2-((2’-mercaptoethyl)amino)acetamide]. Although these two complexes differ only by a single amine vs. amidate ligand, the chemical properties of them are quite different. The stronger in-plane ligand field in the bisamidate complex (NiII(L1))2− (2) results in an increase in the energies of the d → d transitions and a considerably more negative oxidation potential. Furthermore, while the bisamidate complex (NiII(L1))2− (2) readily forms a trinuclear species (Et4N)2({Ni(L1)}2Ni)·H2O (1) and reacts rapidly with O2, presumably via sulfoxidation, the mixed amine/amidate complex (NiII(HL2))− (3) remains monomeric and is stable for days in air. Interestingly, the NiIII species of the bisamidate complex formed by chemical oxidation with I2 can be detected by electron paramagnetic resonance (EPR) spectroscopy while the mixed amine/amidate complex immediately decomposes upon oxidation. In order to explain these experimentally observed properties, we performed S K-edge X-ray absorption spectroscopy and low-temperature (77 K) electronic absorption measurements as well as both hybrid density functional theory (hybrid-DFT) and spectroscopy oriented configuration interaction (SORCI) calculations

  8. Measurement of Black Carbon Particles and their Mixing State in Wildfire Plumes from New Mexico: Aged Whitewater Baldy Complex in 2012 and Fresh Las Conchas in 2011

    NASA Astrophysics Data System (ADS)

    Aiken, A. C.; Dubey, M. K.; Gorkowski, K.; Mazzoleni, C.; China, S.

    2012-12-01

    Approximately 50% of black carbon (BC) aerosols come from wildfires and are estimated to contribute up to ~0.6 W/m2 warming of the atmosphere globally. Organic carbon (OC) from fires condenses and/or mixes with BC resulting in an overall lower forcing of 0.03 ± 0.12 Wm-2 from biomass burning. However, this reduction depends strongly on the composition of the carbonaceous aerosols and on the mixing state of OC and BC. Detailed model treatments and laboratory measurements indicate that a BC core coated with a non-absorbing OC layer enhances absorption with a positive climate forcing. However, the real-time identification of the coating on this internally mixed BC in the field has only recently become detectable with the analysis of lag times between the scattering and incandescence signals in measurements from the single particle soot photometer (SP2). While fully coated BC has a positive lag time (cBC) in the SP2 data, BC that is located near the surface (nsBC) is associated with a negative lag time (Sedlacek et al. 2012). We investigate BC mixing states in concentrated wildfire plumes from the two largest wildfires in New Mexico's history with different ages. Plumes from the Las Conchas (LC) Fire, a wildfire that occurred in July-August of 2011 and burned ~157K acres, were sampled in the near-field after only a few hours of aging. Older plumes from the Whitewater Baldy (WB) Fire (May-June, 2012) that burned ~300K acres were sampled from further afield with an aging period of 7-9 hours. We find up to 23% of the internally mixed BC to be nsBC in the older WB plume. The nsBC fraction is smaller for the relatively fresh LC plume. Figure 1 shows %nsBC versus plume age as a conceptual framework of increasing %nsBC with age for the wildfire data shown here. SP2 results are corroborated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) of single particles collected on nuclepore membranes that clearly show the shifts in morphology. Furthermore

  9. The mixing of fluids

    SciTech Connect

    Ottino, J.M.

    1989-01-01

    What do the eruption of Krakatau, the manufacture of puff pastry and the brightness of stars have in common Each involves some aspect of mixing. Mixing also plays a critical role in modern technology. Chemical engineers rely on mixing to ensure that substances react properly, to produce polymer blends that exhibit unique properties and to disperse drag-reducing agents in pipelines. Yet in spite of its of its ubiquity in nature and industry, mixing is only imperfectly under-stood. Indeed, investigators cannot even settle on a common terminology: mixing is often referred to as stirring by oceanographers and geophysicists, as blending by polymer engineers and as agitation by process engineers. Regardless of what the process is called, there is little doubt that it is exceedingly complex and is found in a great variety of systems. In constructing a theory of fluid mixing, for example, one has to take into account fluids that can be miscible or partially miscible and reactive or inert, and flows that are slow and orderly or very fast and turbulent. It is therefore not surprising that no single theory can explain all aspect of mixing in fluids and that straightforward computations usually fail to capture all the important details. Still, both physical experiments and computer simulations can provide insight into the mixing process. Over the past several years the authors and his colleague have taken both approaches in an effort to increase understanding of various aspect of the process-particularly of mixing involving slow flows and viscous fluids such as oils.

  10. Mixed Dementia

    MedlinePlus

    ... community Use our Virtual Library Treatment and outcomes back to top Because most people with mixed dementia are diagnosed with a single type of dementia, physicians often base their prescribing decisions on the type of dementia ...

  11. Synthesis, characterization, DNA interaction and cleavage, and in vitro cytotoxicity of copper(II) mixed-ligand complexes with 2-phenyl-3-hydroxy-4(1H)-quinolinone.

    PubMed

    Buchtík, Roman; Trávníček, Zdeněk; Vančo, Ján; Herchel, Radovan; Dvořák, Zdeněk

    2011-10-07

    A series of mixed-ligand complexes [Cu(qui)(L)]NO(3)·xH(2)O (1-6), where Hqui = 2-phenyl-3-hydroxy-4(1H)-quinolinone, L = 2,2'-bipyridine (bpy) (1), 1,10-phenanthroline (phen) (2), bis(2-pyridyl)amine (ambpy) (3), 5-methyl-1,10-phenanthroline (mphen) (4), 5-nitro-1,10-phenanthroline (nphen) (5) and bathophenanthroline (bphen) (6), have been synthesized and fully characterized. The X-ray structures of [Cu(qui)(phen)]NO(3)·H(2)O (2) and [Cu(qui)(ambpy)]NO(3) (3a) show a slightly distorted square-planar geometry in the vicinity of the central copper(II) atom. An in vitro cytotoxicity study of the complexes found significant activity against human osteosarcoma (HOS) and human breast adenocarcinoma (MCF7) cell lines, with the best results for complex 6, where IC(50) equals to 2.1 ± 0.2 μM, and 2.2 ± 0.4 μM, respectively. The strong interactions of the complexes with calf thymus DNA (CT-DNA) and high ability to cleave pUC19 DNA plasmid were found. A correlation has been found between the in vitro cytotoxicity and DNA cleavage studies of the complexes.

  12. Synthesis and characterization of mixed-ligand diimine-piperonal thiosemicarbazone complexes of ruthenium(II): Biophysical investigations and biological evaluation as anticancer and antibacterial agents

    PubMed Central

    Beckford, Floyd A.; Thessing, Jeffrey; Shaloski, Michael; Mbarushimana, P. Canisius; Brock, Alyssa; Didion, Jacob; Woods, Jason; Gonzalez-Sarrías, Antonio; Seeram, Navindra P.

    2011-01-01

    We have used a novel microwave-assisted method developed in our laboratories to synthesize a series of ruthenium-thiosemicarbazone complexes. The new thiosemicarbazone ligands are derived from benzo[d][1,3]dioxole-5-carbaldehyde (piperonal) and the complexes are formulated as [(diimine)2Ru(TSC)](PF6)2 (where the TSC is the bidentate thiosemicarbazone ligand). The diimine in the complexes is either 2,2'-bipyridine or 1,10-phenanthroline. The complexes have been characterized by spectroscopic means (NMR, IR and UV-Vis) as well as by elemental analysis. We have studied the biophysical characteristics of the complexes by investigating their anti-oxidant ability as well as their ability to disrupt the function of the human topoisomerase II enzyme. The complexes are moderately strong binders of DNA with binding constants of 104 M−1. They are also strong binders of human serum albumin having binding constants on the order of 104 M−1. The complexes show good in vitro anticancer activity against human colon cancer cells, Caco-2 and HCT-116 and indeed show some cytotoxic selectivity for cancer cells. The IC50 values range from 7 – 159 μM (after 72 h drug incubation). They also have antibacterial activity against Gram-positive strains of pathogenic bacteria with IC50 values as low as 10 μM; little activity was seen against Gram-negative strains. It has been established that all the compounds are catalytic inhibitors of human topoisomerase II. PMID:21552381

  13. Synthesis and characterization of mixed-ligand diimine-piperonal thiosemicarbazone complexes of ruthenium(II): Biophysical investigations and biological evaluation as anticancer and antibacterial agents.

    PubMed

    Beckford, Floyd A; Thessing, Jeffrey; Shaloski, Michael; Mbarushimana, P Canisius; Brock, Alyssa; Didion, Jacob; Woods, Jason; Gonzalez-Sarrías, Antonio; Seeram, Navindra P

    2011-04-19

    We have used a novel microwave-assisted method developed in our laboratories to synthesize a series of ruthenium-thiosemicarbazone complexes. The new thiosemicarbazone ligands are derived from benzo[d][1,3]dioxole-5-carbaldehyde (piperonal) and the complexes are formulated as [(diimine)(2)Ru(TSC)](PF(6))(2) (where the TSC is the bidentate thiosemicarbazone ligand). The diimine in the complexes is either 2,2'-bipyridine or 1,10-phenanthroline. The complexes have been characterized by spectroscopic means (NMR, IR and UV-Vis) as well as by elemental analysis. We have studied the biophysical characteristics of the complexes by investigating their anti-oxidant ability as well as their ability to disrupt the function of the human topoisomerase II enzyme. The complexes are moderately strong binders of DNA with binding constants of 10(4) M(-1). They are also strong binders of human serum albumin having binding constants on the order of 10(4) M(-1). The complexes show good in vitro anticancer activity against human colon cancer cells, Caco-2 and HCT-116 and indeed show some cytotoxic selectivity for cancer cells. The IC(50) values range from 7 - 159 μM (after 72 h drug incubation). They also have antibacterial activity against Gram-positive strains of pathogenic bacteria with IC(50) values as low as 10 μM; little activity was seen against Gram-negative strains. It has been established that all the compounds are catalytic inhibitors of human topoisomerase II.

  14. New mixed ligand cobalt(II/III) complexes based on the drug sodium valproate and bioactive nitrogen-donor ligands. Synthesis, structure and biological properties

    NASA Astrophysics Data System (ADS)

    Abu Ali, Hijazi; Abu Shamma, Amani; Kamel, Shayma

    2017-08-01

    New cobalt valproate complexes with different nitrogen based ligands were synthesized and characterized using various techniques such as IR, UV-Vis, single crystal X-ray diffraction as well as other physical properties. The general formula of the prepared complexes is [Con(valp)m(L)z], (n = 1, 2 …; m = 1, 2, …; Z = 1, 2 …). The complexes [Co2(valp)4] (1), [Co(valp)2(2-ampy)2] (2) and [Co2(valp)4(quin)2] (3) showed different carboxylate coordination modes. The crystal structures of the complexes 2 and 3 were determined using single crystal X-ray diffraction. Kinetic studies of hydrolysis reactions of BNPP [bis-(p-nitrophenyl)phosphate] with complexes 2 and 3 were performed. The hydrolysis rate of BNPP was studied at different temperatures, pH and concentrations by UV-Vis spectrophotometric method. The results showed that the hydrolysis rate of BNPP was 7.70 × 102 L mol-1 s-1 for (3) and 2.60 × 10-1 L mol-1 s-1 for (2).

  15. Solvent influence on complex formation between Cd2+ and 2-hydroxy-1,4-naphthoquinone in binary mixed nonaqueous solvents at 15-45°C

    NASA Astrophysics Data System (ADS)

    Farazandeh, R.; Rounaghi, G. H.; Ebrahimi, M.; Basafa, S.

    2017-04-01

    The complexation reaction of Cd2+ cation with 2-hydroxy-1,4-naphthoquinone (HNQ) was studied in acetonitrile (AN), 2-PrOH, ethyl acetate (EtOAc), EtOH, dimethylformamide (DMF) and in binary solutions AN-2-PrOH, AN-DMF, AN-EtOH, and AN-EtOAc using conductometric method at 15-45°C. The conductance data show that the stoichiometry of the Cd2+ complex with HNQ in all solvent systems is 1 : 1. In the pure solvents the stability of the complex changes in the order AN > 2-PrOH > EtOH > DMF. The stability of the complex at 25°C in the studied mixtures changes in the following order : AN-EtOAc > AN-2-PrOH > AN-EtOH > AN-DMF. These orders are affected by the nature and composition of the solvent systems and by the temperature. From the temperature dependence data, the thermodynamic functions values (Δ H° and Δ S°) for the complex formation were calculated.

  16. Effect of decomposition and organic residues on resistivity of copper films fabricated via low-temperature sintering of complex particle mixed dispersions

    PubMed Central

    Yong, Yingqiong; Nguyen, Mai Thanh; Tsukamoto, Hiroki; Matsubara, Masaki; Liao, Ying-Chih; Yonezawa, Tetsu

    2017-01-01

    Mixtures of a copper complex and copper fine particles as copper-based metal-organic decomposition (MOD) dispersions have been demonstrated to be effective for low-temperature sintering of conductive copper film. However, the copper particle size effect on decomposition process of the dispersion during heating and the effect of organic residues on the resistivity have not been studied. In this study, the decomposition process of dispersions containing mixtures of a copper complex and copper particles with various sizes was studied. The effect of organic residues on the resistivity was also studied using thermogravimetric analysis. In addition, the choice of copper salts in the copper complex was also discussed. In this work, a low-resistivity sintered copper film (7 × 10−6 Ω·m) at a temperature as low as 100 °C was achieved without using any reductive gas. PMID:28338044

  17. Effect of decomposition and organic residues on resistivity of copper films fabricated via low-temperature sintering of complex particle mixed dispersions

    NASA Astrophysics Data System (ADS)

    Yong, Yingqiong; Nguyen, Mai Thanh; Tsukamoto, Hiroki; Matsubara, Masaki; Liao, Ying-Chih; Yonezawa, Tetsu

    2017-03-01

    Mixtures of a copper complex and copper fine particles as copper-based metal-organic decomposition (MOD) dispersions have been demonstrated to be effective for low-temperature sintering of conductive copper film. However, the copper particle size effect on decomposition process of the dispersion during heating and the effect of organic residues on the resistivity have not been studied. In this study, the decomposition process of dispersions containing mixtures of a copper complex and copper particles with various sizes was studied. The effect of organic residues on the resistivity was also studied using thermogravimetric analysis. In addition, the choice of copper salts in the copper complex was also discussed. In this work, a low-resistivity sintered copper film (7 × 10‑6 Ω·m) at a temperature as low as 100 °C was achieved without using any reductive gas.

  18. Structure, spectroscopy, and theory calculations of mononuclear mixed-ligand copper(II) complex with malonate and 2-propylimidazole, [Cu(mal)(PIM) 2(H 2O)

    NASA Astrophysics Data System (ADS)

    Peng, Xian; Cui, Guang-Hua; Li, De-Jie; Wu, Shang-Zhuo; Yu, Ya-Mei

    2010-05-01

    A mononuclear copper(II) complex, [Cu(mal)(PIM) 2(H 2O)] (1) [mal = malonate dianion, PIM = 2-propylimidazole] has been synthesized and characterized by elemental analysis, IR, UV-Vis, TG-DTA, and single crystal X-ray diffraction. The center Cu(II) atom in the complex has a distorted square-pyramidal geometry, being coordinated by two nitrogen atoms and three oxygen atoms. Density Functional Theory (DFT) with the B3LYP method and time-dependent DFT calculations were performed to provide insight into the structural, electronic, and electronic spectroscopic properties of the complex 1, and the UV-Vis spectrum of the title compound has been discussed on this basis. All the absorption bands in UV-Vis spectrum are mostly π/( P, σ) → d x2-y2 ligand-to-metal charge transfer (LMCT) transition, together with partial d → d ligand field (LF) transition.

  19. Effect of decomposition and organic residues on resistivity of copper films fabricated via low-temperature sintering of complex particle mixed dispersions.

    PubMed

    Yong, Yingqiong; Nguyen, Mai Thanh; Tsukamoto, Hiroki; Matsubara, Masaki; Liao, Ying-Chih; Yonezawa, Tetsu

    2017-03-24

    Mixtures of a copper complex and copper fine particles as copper-based metal-organic decomposition (MOD) dispersions have been demonstrated to be effective for low-temperature sintering of conductive copper film. However, the copper particle size effect on decomposition process of the dispersion during heating and the effect of organic residues on the resistivity have not been studied. In this study, the decomposition process of dispersions containing mixtures of a copper complex and copper particles with various sizes was studied. The effect of organic residues on the resistivity was also studied using thermogravimetric analysis. In addition, the choice of copper salts in the copper complex was also discussed. In this work, a low-resistivity sintered copper film (7 × 10(-6) Ω·m) at a temperature as low as 100 °C was achieved without using any reductive gas.

  20. Novel mixed ligand complexes of bioactive Schiff base (E)-4-(phenyl (phenylimino) methyl) benzene-1,3-diol and 2-aminophenol/2-aminobenzoic acid: Synthesis, spectral characterization, antimicrobial and nuclease studies

    NASA Astrophysics Data System (ADS)

    Subbaraj, P.; Ramu, A.; Raman, N.; Dharmaraja, J.

    2014-01-01

    A novel bidentate Schiff base ligand has been synthesized using 2,4-dihydroxybenzophenone and aniline. Its mixed ligand complexes of MAB type [M = Mn(II), Co(II), Ni(II), Cu(II) and Zn(II); HA = Schiff base and B = 2-aminophenol/2-aminobenzoic acid] have been synthesized and characterized on the basis of spectral data UV-Vis, IR, 1H NMR, FAB-Mass, EPR, SEM and magnetic studies. All the complexes were soluble in DMF and DMSO. Elemental analysis and molar conductance values indicate that the complexes are non-electrolytes. HA binds with M(II) ions through azomethine and deprotonated phenolic group and B binds through the primary amine group and deprotonated phenolic/carboxylic groups. Using FAB-Mass the cleavage pattern of the ligand (HA) has been established. All the complexes adopt octahedral geometry around the metal ions. It has been confirmed with the help of UV-Vis, IR, 1H NMR and FAB-Mass spectral data. DNA binding activities of the complexes 1d and 2d are studied by UV-Vis spectroscopy and cleavage studies of Schiff base ligand and its complexes 1d and 2d have been by agarose gel electrophoresis method. In vitro biological activities of the free ligand (HA) and their metal complexes (1a-1e and 2a-2e) were screened against few bacteria, Escherichia coli, Staphylococcus saphyphiticus, Staphylococcus aureus, Pseudomonas aeruginosa and fungi Aspergillus niger, Enterobacter species, Candida albicans by well diffusion technique.

  1. An electron-flow model can predict complex redox reactions in mixed-culture fermentative bioH2: microbial ecology evidence.

    PubMed

    Lee, Hyung-Sool; Krajmalinik-Brown, Rosa; Zhang, Husen; Rittmann, Bruce E

    2009-11-01

    We developed the first model for predicting community structure in mixed-culture fermentative biohydrogen production using electron flows and NADH2 balances. A key assumption of the model is that H2 is produced only via the pyruvate decarboxylation-ferredoxin-hydrogenase pathway, which is commonly the case for fermentation by Clostridium and Ethanoligenens species. We experimentally tested the model using clone libraries to gauge community structures with mixed cultures in which we did not pre-select for specific bacterial groups, such as spore-formers. For experiments having final pHs 3.5 and 4.0, where H2 yield and soluble end-product distribution were distinctly different, we established stoichiometric reactions for each condition by using experimentally determined electron equivalent balances. The error in electron balancing was only 3% at final pH 3.5, in which butyrate and acetate were dominant organic products and the H2 yield was 2.1 mol H2/mol glucose. Clone-library analysis showed that clones affiliated with Clostridium sp. BL-22 and Clostridium sp. HPB-16 were dominant at final pH 3.5. For final pH 4.0, the H2 yield was 0.9 mol H2/mol glucose, ethanol, and acetate were the dominant organic products, and the electron balance error was 13%. The significant error indicates that a second pathway for H2 generation was active. The most abundant clones were affiliated with Klebsiella pneumoniae, which uses the formate-cleavage pathway for H2 production. Thus, the clone-library analyses confirmed that the model predictions for when the pyruvate decarboxylation-ferredoxin-hydrogenase pathway was (final pH 3.5) or was not (final pH 4.0) dominant. With the electron-flow model, we can easily assess the main mechanisms for H2 formation and the dominant H2-producing bacteria in mixed-culture fermentative bioH2.

  2. Syntheses, crystal structures, and characterization of three 1D, 2D and 3D complexes based on mixed multidentate N- and O-donor ligands

    NASA Astrophysics Data System (ADS)

    Yang, Huai-Xia; Liang, Zhen; Hao, Bao-Lian; Meng, Xiang-Ru

    2014-10-01

    Three new 1D to 3D complexes, namely, {[Ni(btec)(Himb)2(H2O)2]·6H2O}n (1), {[Cd(btec)0.5(imb)(H2O)]·1.5H2O}n (2), and {[Zn(btec)0.5(imb)]·H2O}n (3) (H4btec=1,2,4,5-benzenetetracarboxylic acid, imb=2-(1H-imidazol-1-methyl)-1H-benzimidazole) have been synthesized by adjusting the central metal ions. Single-crystal X-ray diffraction analyses reveal that complex 1 possesses a 1D chain structure which is further extended into the 3D supramolecular architecture via hydrogen bonds. Complex 2 features a 2D network with Schla¨fli symbol (53·62·7)(52·64). Complex 3 presents a 3D framework with a point symbol of (4·64·8)(42·62·82). Moreover, their IR spectra, PXRD patterns, thermogravimetric curves, and luminescent emissions were studied at room temperature.

  3. Mixed metal bis(mu-oxo) complexes with [CuM(mu-O)2]n+(M = Ni(III) or Pd(II)) cores.

    PubMed

    Aboelella, Nermeen W; York, John T; Reynolds, Anne M; Fujita, Koyu; Kinsinger, Christopher R; Cramer, Christopher J; Riordan, Charles G; Tolman, William B

    2004-08-07

    Two highly reactive heterodinuclear bis(mu-oxo) complexes were prepared by combining mononuclear peroxo species with reduced metal precursors at -80 degrees C and were identified by UV-vis, EPR/NMR, and resonance Raman spectroscopy, with corroboration in the case of the CuPd system from density functional calculations.

  4. Determination of Equilibrium Constants of Some Novel Antioxidant Compounds and Study on their Complexes with Some Divalent Metal ions in Ethanol-water Mixed.

    PubMed

    Atabey, Hasan; Findik, Esra; Sari, Hayati; Ceylan, Mustafa

    2012-12-01

    This study aims to investigate the nature and type of complexes formed in solution, between novel antioxidant compounds [P1(4-(1-(3-hydroxy-4-methoxyphenyl)propyl)benzene-1,2-diol) and P2(4-(1-(3-hydroxy-4-methoxyphenyl)propyl)benzene-1,3-diol)] and the ions Cu2+, Ni2+, Zn2+ and Co2+. Potentiometric titration technique was used to follow the formation of complexes during the course of coordination. The stability of the complexes formed was controlled through the determination of stability constants in aqueous ethanol solution at 25 ± 0.1 C° and ionic strength of 0.1 M NaCl. Basicity of the ligand was also assessed by the determination of the dissociation constants of the ligand. All the constants were computed by computer refinement of pH-volume data using the SUPERQUAD program. The species distribution diagram of each type of complex has been obtained after computer calculation process.

  5. Mixed cerium-platinum oxides: Electronic structure of [CeO]Ptn (n = 1, 2) and [CeO2]Pt complex anions and neutrals

    NASA Astrophysics Data System (ADS)

    Ray, Manisha; Kafader, Jared O.; Topolski, Josey E.; Jarrold, Caroline Chick

    2016-07-01

    The electronic structures of several small Ce-Pt oxide complexes were explored using a combination of anion photoelectron (PE) spectroscopy and density functional theory calculations. Pt and Pt2 both accept electron density from CeO diatomic molecules, in which the cerium atom is in a lower-than-bulk oxidation state (+2 versus bulk +4). Neutral [CeO]Pt and [CeO]Pt2 complexes are therefore ionic, with electronic structures described qualitatively as [CeO+2]Pt-2 and [CeO+]Pt2-, respectively. The associated anions are described qualitatively as [CeO+]Pt-2 and [CeO+]Pt2-2, respectively. In both neutrals and anions, the most stable molecular structures determined by calculations feature a distinct CeO moiety, with the positively charged Ce center pointing toward the electron rich Pt or Pt2 moiety. Spectral simulations based on calculated spectroscopic parameters are in fair agreement with the spectra, validating the computationally determined structures. In contrast, when Pt is coupled with CeO2, which has no Ce-localized electrons that can readily be donated to Pt, the anion is described as [CeO2]Pt-. The molecular structure predicted computationally suggests that it is governed by charge-dipole interactions. The neutral [CeO2]Pt complex lacks charge-dipole stabilizing interactions, and is predicted to be structurally very different from the anion, featuring a single Pt-O-Ce bridge bond. The PE spectra of several of the complexes exhibit evidence of photodissociation with Pt- daughter ion formation. The electronic structures of these complexes are related to local interactions in Pt-ceria catalyst-support systems.

  6. DNA binding of iron(II) mixed-ligand complexes containing 1,10-phenanthroline and 4,7-diphenyl-1,10-phenanthroline.

    PubMed

    Mudasir; Yoshioka, N; Inoue, H

    1999-01-01

    Absorption spectroscopy and circular dichroism (CD) have been used to characterize the DNA binding of [Fe(phen)3]2+, [Fe(phen)2(DIP)]2+ and [Fe(phen)(DIP)2]2+ where phen and DIP stand for 1,10-phenanthroline and 4,7-diphenyl-1,10-phenanthroline, respectively. Both [Fe(phen)3]2+ and [Fe(phen)2(DIP)]2+ bind weakly to calf thymus DNA (CT-DNA) in an electrostatic mode, while [Fe(phen)(DIP)2]2+ binds more strongly to CT-DNA, possibly in an intercalation mode. The hypochromicity, red shift and Kb increase in the order [Fe(phen)3]2+ < [Fe(phen)2(DIP)]2+ < [Fe(phen)(DIP)2]2+ in accordance with the increase in size and hydrophobicity of the iron(II) complexes. The thermodynamic parameters obtained suggest that the DNA binding of both [Fe(phen)3]2+ and [Fe(phen)2(DIP)]2+ is entropically driven, while that of [Fe(phen)(DIP)2]2+ is enthalpically driven. A strong CD spectrum in the UV and visible region develops upon addition of CT-DNA into the racemate solution of each iron(II) complex (Pfeiffer effect). This has revealed that a shift in diastereomeric inversion equilibrium takes place in the solution to yield an excess of one of the DNA-complex diastereomers. The striking resemblance of the CD spectral profiles to those of the pure delta-enantiomer indicates that the delta-enantiomer of the iron(II) complexes is preferentially bound to CT-DNA. The mechanism of the development of Pfeiffer CD is proposed on the basis of kinetic studies on the DNA binding of the racemic iron(II) complexes.

  7. Basalt Magma, Whisky and Tequila: finely-crafted mixes of small liquid batches that defy the parent liquid concept but whose complexities teach us much

    NASA Astrophysics Data System (ADS)

    Rubin, K. H.; Sinton, J. M.; Perfit, M. R.

    2015-12-01

    Basalt is the most ubiquitous magma type we know of in the solar system. It comes in various varieties manifested as compositional sub groups, erupts from a wide variety of volcanic systems and tectonic settings, and its eruptions span many order of magnitude in duration and volume. Igneous petrology, thermodynamics, geochemistry, and geodynamical modelling have been used to develop a sophisticated understanding of source lithologies, compositions and formation conditions (e.g., pressure and temperature) for parent melts and their subsequent transport, storage and evolution. These demonstrate some striking systematics as a function of volcano tectonic setting (on Earth). Yet much like Whisky, what makes it into the bottle, or the eruption, is a mixture of different liquids with unique characteristics, sometimes stirred so well that successive batches are indistinguishable, and sometimes stirred more incompletely, preserving small batch characters that are unique. Recently, geochemical and petrological studies in high spatial density within the products of individual eruptions have shown chemical and mineralogical evidence for incompletely mixed heterogeneous magmas in a majority of systems examined, begging the question of when, if ever, is it realistic to speak of a single parent magma composition, and even in cases where it apparently is, if these are instead just more thoroughly stirred multi-parent magmas. For instance, do monogenetic fields really erupt basalts of more varied parent melt compositions than large hot spot and flood basalt eruptions, or are they just more poorly stirred? This presentation will focus on work by ourselves and others constraining spatial and temporal single-eruption basaltic magma histories at different settings, using them to unravel the time and space scales of magma formation and mixing, how these translate to the assembly of an erupted basalt magma, and the implications for deducing things about and from presumed parents.

  8. Synthesis, structure, and properties of a mixed-valent triiron complex of tetramethyl reductic acid, an ascorbic acid analogue, and its relationship to a functional non-heme iron oxidation catalyst system.

    PubMed

    Kim, YooJin; Feng, Xudong; Lippard, Stephen J

    2007-07-23

    The purple triiron(II,III,III) complex, [Fe(3)Cl(2)(TMRASQ)(4)(HTMRA)(2)] x C(5)H(12) (1 x C(5)H(12)), where H(2)TMRA is a tetramethyl reductic acid, 4,4,5,5-tetramethyl-2,3-dihydroxy-2-cyclopenten-1-one, and HTMRASQ is the semiquinone form of this ligand, was prepared from (Et(4)N)(2)[Fe(2)OCl(6)] and H(2)TMRA and characterized by X-ray crystallography, Mössbauer spectroscopy, and redox titrations. The physical properties of the complex in solution are consistent with its mixed-valent character, as delineated by a solid-state structure analysis. Assignments of the iron and ligand oxidation states in the crystal were made on the basis of a valence bond sum analysis and the internal ligand geometry. As the first well-characterized iron complex of an ascorbic acid H(2)AA analogue, 1 provides insight into the possible coordination geometry of the family of complexes containing H(2)AA and its analogues. In the presence of air and H(2)TMRA, 1 is able to catalyze the oxidation of cyclohexane to cyclohexanol with remarkable selectivity, but the nature of the true catalyst remains unknown.

  9. Syntheses, characterization and antioxidant activity studies of mixed-ligand copper(II) complexes of 2,2‧-bipyridine and glycine: The X-ray crystal structure of [Cu(BPy)(Gly)]ClO4

    NASA Astrophysics Data System (ADS)

    Ibrahim, Mohamed M.; Ramadan, Abd El-Motaleb M.; Shaban, Shaban Y.; Mersal, Gaber A. M.; El-Shazly, Samir A.; Al-Juaid, Salih

    2017-04-01

    A series of mixed-ligand complexes, viz., [CuLL'X]Y {L = bipyridine; L' = glycine; X = 0, Y = ClO4- (1); X = Cl, Y = 2H2O (2); X = H2O, Y = NO3- (3); X = CH3COO-, Y = H2O (4)} and {[Cu(Gly)(BPy)]2-μ-(SO4)}(5)} have been synthesized and characterized by means of elemental analysis, spectroscopic (FT-IR, UV-Vis and ESR), and thermal analysis, as well as magnetic moment measurements. Spectral and X-ray structural features led to the conclusion that complexes 2-5 have square-pyramidal environments around copper(II) center with coordination chromophores CuN3OCl and CuN3O2, respectively. Whereas complex 1 displays square planar geometry. The quasi-reversible CuII/CuI redox couple slightly improves its reversibility with considerable decrease in current intensity. Additionally, the antioxidant (superoxide dismutase and catalase) biomimetic catalytic activities of the obtained complexes have been tested and found to be promising candidates as dual functional mimic enzyme to serve for complete reactive oxygen species (ROS) detoxification, both with respect to the superoxide radicals and the related peroxides.

  10. Polyelectrolyte complex formation and stability when mixing polyanions and polycations in salted media: a model study related to the case of body fluids.

    PubMed

    Etrych, Tomás; Leclercq, Laurent; Boustta, Mahfoud; Vert, Michel

    2005-06-01

    Controlled drug delivery and gene transfection involve contact of artificial polyelectrolytic systems that can interact dramatically with biopolymers and cells when they are introduced in blood. Given the complexity of body aqueous media in terms of physical chemistry, a model approach was selected in attempt to understand the behavior of artificial polyelectrolytes introduced in body fluids. Selection in terms of molecular weight was highlighted in a previous paper. In the present study the formation and the stability of fractions obtained when a polycation is added to a polyanion according to a titrating process mimicking injection into blood was considered for different polycation/polyanion couples. Poly(amino serinate) and poly(L-lysine) were used as polybases, and poly(acrylic acid), poly(L-lysine citramide) and poly(L-lysine citramide imide) as polyacids. Four fractions corresponding to different positive/negative charge ratios were formed for each couple. At low polyion concentration (13 mg/L) and given salt concentration, the stability of the complex fractions depended on molecular weight and charge density of the polyions. The NaCl concentration required to destabilize the different interpolyelectrolyte complexes was found to decrease from the first fraction to the fourth one. Upon decreasing the salt concentration, macroscopic flocculation occurred in the case of PLL/PAA complex fractions only. For the other couples, dynamic light scattering showed that several hundreds nanometer sized particles were formed that were stable in a broad range of NaCl concentration, including the physiological 0.15 ionic strength. At higher polyion concentrations, stable solid precipitate was formed regardless of the system. The absence of flocculation in the case of highly diluted poly(L-lysine citramide) and poly(L-lysine citramide imide) polyanions in salted media is assigned to the presence of non-ionic hydroxyl and amide polar groups along the complexed chains. Data

  11. Polyoxometalate-based organic-inorganic hybrid compounds containing transition metal mixed-organic-ligand complexes of N-containing and pyridinecarboxylate ligands.

    PubMed

    Zhao, De-Chuan; Hu, Yang-Yang; Ding, Hong; Guo, Hai-Yang; Cui, Xiao-Bing; Zhang, Xiao; Huo, Qi-Sheng; Xu, Ji-Qing

    2015-05-21

    Five new organic–inorganic hybrid compounds based on the Keggin-type polyoxoanion [SiW12O40]4−, namely [Cu3(2,2′-bpy)3(inic)(μ2-OH)(H2O)][SiW12O40]·2H2O (1), [Cu6(phen)6(μ3-Cl)2(μ2-Cl)2Cl2(inic)2][SiW12O40]·6H2O (2), [Cu2(hnic)(2,2′-bpy)2Cl]2[H2SiW12O40] (3), [Cu2(nic)(phen)2Cl2]2[SiW12O40] (4) and [Cu2(pic)(2,2′-bpy)2Cl]2[SiW12O40] (5) (inic = isonicotinic acid, hnic = 2-hydroxy-nicotinic acid, nic = nicotinic acid, pic = picolinic acid, 2,2′-bpy = 2,2′-bipyridine, phen = 1,10-phenanthroline) have been synthesized and characterized by IR, UV-Vis, XPS, XRD, cyclic voltammetric measurements, photoluminescence analysis and single crystal X-ray diffraction analysis. Crystal analysis reveals that compound 1 exhibits a 2-D double layered framework structure constructed from [SiW12O40]4− and copper-aqua-2,2′-bipy-hydroxyl-isonicotinate complexes. Compound 2 is a 0-D discrete structure formed by [SiW12O40]4− and copper-chloro-isonicotinate-phenanthroline complexes. Compound 3 shows a 1-D single chain structure based on the linkage of copper-2,2-bpy-chloro-2-hydroxy-nicotinate complexes and [SiW12O40]4−. Compounds 4 and 5 both contain polyoxometalate supported transition metal complexes, one is a polyoxometalate supported copper-chloro-nicotinate-phenanthroline complex in 4, and the other is a polyoxometalate supported copper-2,2-bpy-chloro-nicotinate complex in 5. It should be noted that nicotinic, isonicotinic and picolinic acids are structural isomers and 2-hydroxy-nicotinic acid is an in situ hydroxylated product of nicotinic acid. In addition, photocatalytic degradation of Rhodamine B (RhB) by compounds 1–5 has been investigated in aqueous solutions.

  12. Ion mixing

    NASA Technical Reports Server (NTRS)

    Matteson, S.; Nicolet, M.-A.

    1983-01-01

    Recent experimental studies of the ion-mixing phenomenon are summarized. Ion mixing is differentiated from ion implantation and shown to be a useful technique for overcoming the sputter-dependent limitations of implantation processes. The fundamental physical principles of ion/solid interactions are explored. The basic experimental configurations currently in use are characterized: bilayered samples, multilayered samples, and samples with a thin marker layer. A table listing the binary systems (metal-semiconductor or metal-metal) which have been investigated using each configuration is presented. Results are discussed, and some sample data are plotted. The prospects for future application of ion mixing to the alteration of solid surface properties are considered. Practical applications are seen as restricted by economic considerations to the production of small, expensive components or to fields (such as the semiconductor industry) which already have facilities for ion implantation.

  13. Structural, molecular orbital and optical characterizations of solvatochromic mixed ligand copper(II) complex of 5,5-Dimethyl cyclohexanate 1,3-dione and N,N,N";,N";N″-pentamethyldiethylenetriamine

    NASA Astrophysics Data System (ADS)

    Taha, A.; Farag, A. A. M.; Ammar, A. H.; Ahmed, H. M.

    2014-03-01

    In this work, a new solvatochromic mononuclear mixed ligand complex with the formula, Cu(DMCHD)(Me5dien)NO3 (where, DMCHD = 5,5-Dimethyl cyclohexanate 1,3-dione and (Me5dien) = N,N,N";,N";N″-pentamethyldiethylenetriamine was synthesized and characterized by analytical, spectral, magnetic, molar conductance, thermal gravimetric analysis (TGA), X-ray diffraction (XRD) and transmission electron microscope (TEM) measurements. The formation constant-value for copper (II)-DMCHD was found to be much lower than the expected for similar β-diketones, revealing monobasic unidentate nature of this ligand. The d-d absorption bands of the prepared complex exhibit a color changes in various solvent (solvatochromic). Specific and non-specific interactions of solvent molecules with the complex were investigated using Multi Parametric Linear Regression Analysis (MLRA). Structural parameters of the free ligands and their Cu (II) - complex were calculated on the basis of semi-empirical PM3 level and compared with the experimental data. The crystallite size and morphology of Cu(DMCHD)(Me5dien)NO3 were examined using XRD analysis and TEM, revealing that the complex is well crystalline and correspond to the monoclinic crystal structure. The lattice strain and mean crystallite size were estimated by Williamson-Hall (W-H) plot using X-ray diffraction data. The main important absorption parameters such as extinction molar coefficient, oscillator strength and electric dipole strength of the principal optical transitions in the UV-Vis region were calculated. The analysis of absorption coefficient near the fundamental absorption edge reveals that the optical band gaps are direct allowed transitions with values of 2.78 eV and 3.59 eV. The present copper (II) complex was screened for its antimicrobial activity against Staphylococcus Aureus and Bacillus Subtilis as Gram-positive bacteria, Escherichia Coli and Salmonella Typhimurium as Gram-negative bacteria and Candida Albicans as fungus

  14. Investigation of Novel Electrode Materials for Electrochemically-Based Remediation of High- and Low-Level Mixed Wastes in the DOE Complex - Final Report

    SciTech Connect

    Lewis, N.S.; Anderson, M.

    2000-12-01

    New materials are investigated, based on degenerately-doped titanias, for use in the electrochemical degradation of organics and nitrogen-containing compounds in sites of concern to the DOE remediation effort. The data collected in this project appear to provide a rational approach for design of more efficient nanoporous electrodes. Also, osmium complexes appear to be promising candidates for further optimization in operating photo electrochemical cells for solar energy conversion applications.

  15. Mixed-ligand complexes of yttrium-90 dialkyldithiocarbamates with 1,10-phenanthroline as a possible agent for therapy of hepatocellular carcinoma.

    PubMed

    Lopez, A; Noiret, N; Garin, E; Lepareur, N

    2014-12-01

    Yttrium-90 is a radioelement which has found wide use in targeted radionuclide therapy because of its attractive physical and chemical properties. Radioembolisation of hepatocellular carcinoma with radiolabelled Lipiodol is a method of choice. We have synthesised a series of alkyldithiocarbamate yttrium complexes, easily extracted into Lipiodol due to their high lipophilicity. Among the prepared series, a new radioconjugate, which is stable over an extended period of time, has been prepared, and could represent a potential treatment procedure for hepatocellular carcinoma.

  16. Synthesis and characterization of d10 metal complexes with mixed 1,3-di(1H-imidazol-4-yl)benzene and multicarboxylate ligands

    NASA Astrophysics Data System (ADS)

    Chen, Zhi-Hao; Zhao, Yue; Chen, Shui-Sheng; Wang, Peng; Sun, Wei-Yin

    2013-06-01

    Seven new coordination polymers [Zn(H2L)(mbdc)] (1), [Zn(H3L)(btc)] (2), [Zn(H2L)(Hbtc)] (3), [Zn(H2L)(Hbtc)]·H2O (4), [Zn2(H2L)(btc)(μ2-OH)] (5), [Cd(H2L)(mbdc)] (6) and [Cd3(H2L)2(btc)2(H2O)]·5H2O (7) were synthesized by reactions of the corresponding metal salt with rigid ligand 1,3-di(1H-imidazol-4-yl)benzene (H2L) and different carboxylic acids of 1,3-benzenedicarboxylic acid (H2mbdc) and benzene-1,3,5-tricarboxylic acid (H3btc), respectively. The results of X-ray crystallographic analysis indicate that complex 1 is 1D chain while 2 is a (3,3)-connected 2D network with Point (Schläfli) symbol of (4,82). Complexes 3 and 6 are 2D networks, 4 is a 3-fold interpenetrating 3D framework with Point (Schläfli) symbol of (65,8) and 5 is a (3,8)-connected 2D network with Point (Schläfli) symbol of (3,42)2(34,46,56,68,73,8), while 7 is a (3,10)-connected 3D net with Schläfli symbol of (3,4,5)2(34,48,518,612,72,8). The thermal stability and photoluminescence of the complexes were investigated. Furthermore, DFT calculations were performed for 2-4 to discuss the temperature controlled self-assembly of the complexes.

  17. Synthesis, characterization, dynamics and reactivity toward amination of η3-allyl palladium complexes bearing mixed ancillary ligands. Evaluation of the electronic characteristics of the ligands from kinetic data.

    PubMed

    Canovese, Luciano; Visentin, Fabiano; Levi, Carlo; Dolmella, Alessandro

    2011-01-28

    On the basis of an original protocol, we have synthesized several complexes of the type [Pd(η(3)-C(3)H(3)R(2))(LL')]ClO(4) (R = H, Me; L, L' = PPh(3), P(OEt)(3), 2,6-dimethylphenylisocyanide, t-butylisocyanide, 1,3-dimesitylimidazolidine, 1,3-dimesitylimidazol-2-ylidene). The complexes, some of which are completely new species, were fully characterized and their behaviour in solution was studied by means of (1)H NMR. The reactions of the complexes bearing the symmetric allyl moiety [Pd(η(3)-C(3)H(5))(LL')]ClO(4) with piperidine in the presence of the olefin dimethylfumarate were followed under kinetically controlled conditions. Formation of allyl-amine and of the palladium(0) derivatives [Pd(η(2)-dmfu)(LL'] was observed. The reaction rates k(2) proved to be strongly dependent on the ancillary ligand nature and allowed a direct comparison among the electronic characteristics of the ligands. The reactivity trend determined appears to be mainly influenced by the capability of the ancillary ligands in transferring electron density to the metal centre and consequently on the allyl fragment.

  18. Lanthanide dinuclear complexes constructed from mixed oxygen-donor ligands: the effect of substituent positions of the neutral ligand on the magnetic dynamics in Dy analogues.

    PubMed

    Zhu, Wen-Hua; Li, Shan; Gao, Chen; Xiong, Xia; Zhang, Yan; Liu, Li; Powell, Annie K; Gao, Song

    2016-03-21

    Two series of lanthanide dinuclear complexes with the general formulae, [Ln(n-PNO)(Bza)3(H2O)] {Bza = benzoic acid; n = 3, n-PNO = 3-picoline N-oxide, Dy(1) and Er(2); and n = 4, n-PNO = 4-picoline N-oxide, Nd(3), Eu(4), Gd(5), Tb(6), Dy(7), Er(8) and Y(9)} have been successfully synthesized by the hydrothermal method. Single-crystal X-ray diffraction experiments illustrate that the two series of compounds possess similar carboxylic ligand-bridged dinuclear structure and coordination geometry around the lanthanide ions despite the different methyl-substituent positions on the neutral ligand. Comparative studies of the Dy analogues in the static-field measurements reveal only a little difference with a small butterfly-shaped opening for complex 1 and a close hysteresis loop for 7 at 2.0 K. However, systematic investigations of the alternating-current (ac) measurements indicate that the different substituent positions of the picoline N-oxide ligand have a significant effect on the magnetic relaxation dynamics. A more substantial suppression of the quantum tunnelling of magnetization (QTM) effect and pronounced slow magnetic relaxation were observed in complex 7 as compared to 1 under both zero and a 1 kOe static field.

  19. Synthesis and study of the spectroscopic and redox properties of Ru(II),Pt(II) mixed-metal complexes bridged by 2,3,5,6-tetrakis(2-pyridyl)pyrazine.

    PubMed

    Zhao, Shengliang; Arachchige, Shamindri M; Slebodnick, Carla; Brewer, Karen J

    2008-07-21

    The mixed-metal supramolecular complexes [(tpy)Ru(tppz)PtCl](PF6)3 and [ClPt(tppz)Ru(tppz)PtCl](PF6)4 (tpy = 2,2':6',2''-terpyridine and tppz = 2,3,5,6-tetrakis(2-pyridyl)pyrazine) were synthesized and characterized. These complexes contain ruthenium bridged by tppz to platinum centers to form stereochemically defined linear assemblies. X-ray crystallographic determinations of the two complexes confirm the identity of the metal complexes and reveal intermolecular interactions of the Pt sites in the solid state for [(tpy)Ru(tppz)PtCl](PF6)3 with a Pt...Pt distance of 3.3218(5) A. The (1)H NMR spectra show the expected splitting patterns characteristic of stereochemically defined mixed-metal systems and are assigned with the use of (1)H-(1)H COSY and NOESY. Electronic absorption spectroscopy displays intense ligand-based pi --> pi* transitions in the UV and MLCT transitions in the visible. Electrochemically [(tpy)Ru(tppz)PtCl](PF6)3 and [ClPt(tppz)Ru(tppz)PtCl](PF6)4 display reversible Ru (II/III) couples at 1.63 and 1.83 V versus Ag/AgCl, respectively. The complexes display very low potential tppz (0/-) and tppz(-/2-) couples, relative to their monometallic synthons, [(tpy)Ru(tppz)](PF6)2 and [Ru(tppz)2](PF6)2, consistent with the bridging coordination of the tppz ligand. The Ru(dpi) --> tppz(pi*) MLCT transitions are also red-shifted relative to the monometallic synthons occurring in the visible centered at 530 and 538 nm in CH3CN for [(tpy)Ru(tppz)PtCl](PF6)3 and [ClPt(tppz)Ru(tppz)PtCl](PF6)4, respectively. The complex [(tpy)Ru(tppz)PtCl](PF6)3 displays a barely detectable emission from the Ru(dpi) --> tppz(pi*) (3)MLCT in CH 3CN solution at RT. In contrast, [ClPt(tppz)Ru(tppz)PtCl](PF6)4 displays an intense emission from the Ru(dpi) --> tppz(pi*) (3)MLCT state at RT with lambda max(em) = 754 nm and tau = 80 ns.

  20. Synthesis, characterization and thermal studies of binary and/or mixed ligand complexes of Cd(II), Cu(II), Ni(II) and Co(III) based on 2-(Hydroxybenzylidene) thiosemicarbazone: DNA binding affinity of binary Cu(II) complex.

    PubMed

    Saif, M; Mashaly, Mahmoud M; Eid, Mohamed F; Fouad, R

    2012-06-15

    A new series of metal complexes of Cd(II), Cu(II), Ni(II) and Co(III) with Schiff base ligand, H(2)L, 2-(Hydroxybenzylidene) thiosemicarbazone were synthesized. The mixed ligand complexes were prepared by using glycine (Gly), 2-aminopyridine (2-Ampy) and 1,10-phenanthroline (Phen) as secondary ligands. The structure of these complexes was identified and confirmed by elemental analysis, molar conductivity, UV-Vis, FT-IR and (1)H NMR spectroscopy and magnetic moment measurements as well as TG-DSC technique. The discussions of the prepared complexes indicate that the ligand behaves as a monoanionic tridentate ligand through ONS donor sites. Thermal studies suggested a mechanism for the degradation of the metal complexes as a function of temperature supporting the chelation modes and showed the possibility of obtaining new complexes pyrolytically in the solid state which cannot be synthesized from the solution. The absorption studies support that the binary Cu(II) complex exhibits a significant binding affinity to HS-DNA through intercalative mode. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. The physical chemistry of coordinated aqua-, ammine-, and mixed-ligand Co2+ complexes: DFT studies on the structure, energetics, and topological properties of the electron density.

    PubMed

    Varadwaj, Pradeep R; Marques, Helder M

    2010-03-07

    Spin-unrestricted DFT-X3LYP/6-311++G(d,p) calculations have been performed on a series of complexes of the form [Co(H(2)O)(6-n)(NH(3))(n)](2+) (n = 0-6) to examine their equilibrium gas-phase structures, energetics, and electronic properties in their quartet electronic ground states. In all cases Co(2+) in the energy-minimised structures is in a pseudo-octahedral environment. The calculations overestimate the Co-O and Co-N bond lengths by 0.04 and 0.08 A, respectively, compared to the crystallographically observed mean values. There is a very small Jahn-Teller distortion in the structure of [Co(H(2)O)(6)](2+) which is in contrast to the very marked distortions observed in most (but not all) structures of this cation that have been observed experimentally. The successive replacement of ligated H(2)O by NH(3) leads to an increase in complex stability by 6 +/- 1 kcal mol(-1) per additional NH(3) ligand. Calculations using UB3LYP give stabilisation energies of the complexes about 5 kcal mol(-1) smaller and metal-ligand bond lengths about 0.005 A longer than the X3LYP values since the X3LYP level accounts for the London dispersion energy contribution to the overall stabilisation energy whilst it is largely missing at the B3LYP level. From a natural population analysis (NPA) it is shown that the formation of these complexes is accompanied by ligand-to-metal charge transfer the extent of which increases with the number of NH(3) ligands in the coordination sphere of Co(2+). From an examination of the topological properties of the electron charge density using Bader's quantum theory of atoms in molecules it is shown that the electron density rho(c) at the Co-O bond critical points is generally smaller than that at the Co-N bond critical points. Hence Co-O bonds are weaker than Co-N bonds in these complexes and the stability increases as NH(3) replaces H(2)O in the metal's coordination sphere. Several indicators, including the sign and magnitude of the Laplacian of the

  2. From high-temperature orientationally disordered mixed crystals to low-temperature complex formation in the two-component system (CH3)3CBr + Cl3CBr.

    PubMed

    Barrio, María; Negrier, Philippe; Tamarit, Josep Ll; Mondieig, Denise

    2011-02-24

    The phase diagram of the two-component systems (CH(3))(3)CBr + Cl(3)CBr has been experimentally determined by means of differential scanning calorimetry and X-ray powder diffraction techniques from the low-temperature ordered phases to the liquid state. Before melting, both components have the same orientationally disordered (OD) face-centered cubic (FCC) and rhombohedral (R) phases, and the two-phase equilibria [FCC + L] and [R + FCC] are accounted for by means of the existence of an isomorphic relationship between the OD phases of pure compounds. The thermodynamic assessment of such equilibria enables us to get the excess properties of the involved OD phases and to rationalize the existence of a maximum and a minimum in the [R + FCC] equilibrium on the basis of the contribution of the entropic term in the excess Gibbs energy function. At low temperature, two complexes, (CH(3))(3)CBr:Cl(3)CBr (1:1) and (CH(3))(3)CBr:2Cl(3)CBr (1:2), appear. The structures of 1:1 and 1:2 complexes have been determined to be monoclinic (P2(1)/n, c, Z = 4) and hexagonal (P6(3), Z = 6). Within both "ordered" structures, the Cl(3)CBr entities of the asymmetric unit were found to be disordered so that sites have fractional occupancies of 0.75 and 0.25 for Cl and Br atoms, in the same way that it occurs for the low-temperature monoclinic (C2/c, Z = 32) phase of Cl(3)CBr. Finally, the existence of complexes is connected with the special intermolecular interactions appearing between a methyl group and a halogen, as previously inferred by Calvet et al. [T. Calvet et al. J. Chem. Phys. 1999, 110, 4841].

  3. The Diphosphorus Complex [Cp2Mo2(CO)4(η(2)-P2)] as a Building Block for the Synthesis of Mixed-Hybrid Coordination Polymers.

    PubMed

    Moussa, Mehdi Elsayed; Attenberger, Bianca; Fleischmann, Martin; Schreiner, Andrea; Scheer, Manfred

    2016-10-01

    The three-component reaction of the tetrahedral diphosphorus complex [Cp2Mo2(CO)4(η(2)-P2)] (1), with Ag[BF4] (2) in the presence of 2,2'-bipyrimidine (3) leads to the formation of the two novel two-dimensional networks 4 and 5. Compound 4 is a new two-dimensional organometallic-organic hybrid polymer, while derivative 5 represents a unique two-dimensional organometallic-inorganic-organic hybrid polymer. These results show the possibility of synthesizing a new class of coordination polymers, which could not be obtained from two-component reactions with organic molecules in addition of metal ions.

  4. Extended X- ray absorption fine structure study at the K-edge of copper in mixed ligand complexes having benzimidazole as one of the ligands

    NASA Astrophysics Data System (ADS)

    Hinge, V. K.; Joshi, S. K.; Nitin Nair, N.; Singh Verma, Vikram; Shrivastava, B. D.; Prasad, J.; Srivastava, K.

    2014-09-01

    Extended X-ray absorption fine structure (EXAFS) spectra have been studied at the K-edge of copper in some of its biologically important complexes, viz., [Cu(BzImH)4X2] and [Cu(BzIm)2], where X= Cl, Br, 1/2SO4, ClO4, NO3, and BzIm = Benzimidazolato anion. The spectra have been recorded using a bent crystal 0.4 m Cauchois-type transmission spectrograph. The positions of EXAFS maxima and minima have been used to determine the bond lengths in the complexes with the help of three different methods, namely, Levy's, Lytle's and Lytle, Sayers and Stern's (L.S.S.) methods. The phase uncorrected bond lengths have also been determined from Fourier transforms of the experimental spectra. The results obtained from these methods have been discussed and it has been found that the results obtained by L.S.S. method are comparable with the results obtained by Fourier transformation method and that these two methods give phase uncorrected bond lengths.

  5. DNA binding, cytotoxicity and apoptosis induction activity of a mixed-ligand copper(II) complex with taurine Schiff base and imidazole

    NASA Astrophysics Data System (ADS)

    Li, Mei; kong, Lin Lin; Gou, Yi; Yang, Feng; Liang, Hong

    2014-07-01

    A novel binuclear copper(II) complex (complex 1) with taurine Schiff base and imidazole has been synthesized and structurally characterized by single crystal X-ray diffraction, elemental analysis, ESI-MS spectrometry, UV-vis and IR spectroscopy. Single-crystal analysis revealed that 1 displays the sulfonate-bridged dinuclear copper(II) centers. Both copper atoms are five-coordinated and exhibit slightly distorted square pyramidal geometries. Each of copper atom is surrounded by three oxygen atoms and one nitrogen atom from different taurine Schiff base ligands, and one nitrogen atom from one imidazole ligand. The interaction between 1 and calf thymus DNA (CT-DNA) was investigated by UV-vis, fluorescence, circular dichroism (CD) spectra and agarose gel electrophoresis. The experimental results indicated that 1 could bind to CT-DNA via an intercalative mode and show efficient cleavage activity. In addition, 1 showed an antitumor effect on cell cycle and apoptosis. Flow cytometric analysis revealed that MGC-803 cells were arrested in the S phase after treatment with 1. Fluorescence microscopic observation indicated that 1 could induce apoptosis of MGC-803 cells.

  6. Magnetically driven surface mixing

    NASA Astrophysics Data System (ADS)

    Belkin, M.; Snezhko, A.; Aranson, I. S.; Kwok, W.-K.

    2009-07-01

    Magnetic microparticles suspended on the surface of liquid and energized by vertical alternating magnetic field exhibit complex collective behavior. Various immobile and self-propelled self-assembled structures have been observed. Here, we report on experimental studies of mixing and surface diffusion processes in this system. We show that the pattern-induced surface flows have properties of quasi-two-dimensional turbulence. Correspondingly, the surface advection of tracer particle exhibits properties of Brownian diffusion.

  7. Mixed copper-platinum complex formation could explain synergistic antiproliferative effect exhibited by binary mixtures of cisplatin and copper-1,10-phenanthroline compounds: An ESI-MS study.

    PubMed

    Pivetta, Tiziana; Lallai, Viola; Valletta, Elisa; Trudu, Federica; Isaia, Francesco; Perra, Daniela; Pinna, Elisabetta; Pani, Alessandra

    2015-10-01

    Cisplatin, cis-diammineplatinum(II) dichloride, is a metal complex used in clinical practice for the treatment of cancer. Despite its great efficacy, it causes adverse reactions and most patients develop a resistance to cisplatin. To overcome these issues, a multi-drug therapy was introduced as a modern approach to exploit the drug synergy. A synergistic effect had been previously found when testing binary combinations of cisplatin and three copper complexes in vitro, namely, Cu(phen)(OH2)2(OClO3)2, [Cu(phen)2(OH2)](ClO4)2 and [Cu(phen)2(H2dit)](ClO4)2,(phen=1,10-phenanthroline, H2dit=imidazolidine-2-thione), against the human acute T-lymphoblastic leukaemia cell line (CCRF-CEM). In this work [Cu(phen)2(OH2)](ClO4)2 was also tested in combination with cisplatin against cisplatin-resistant sublines of CCRF-CEM (CCRF-CEM-res) and ovarian (A2780-res) cancer cell lines. The tested combinations show a synergistic effect against both the types of resistant cells. The possibility that this effect was caused by the formation of new adducts was considered and mass spectra of solutions containing cisplatin and one of the three copper complexes at a time were measured using electrospray ionisation at atmospheric-pressure mass spectrometry (ESI-MS). A mixed complex was detected and its stoichiometry was assessed on the basis of the isotopic pattern and the results of tandem mass spectrometry experiments. The formed complex was found to be [Cu(phen)(OH)μ-(Cl)2Pt(NH3)(H2O)](+).

  8. Automethylation activities within the mixed lineage leukemia-1 (MLL1) core complex reveal evidence supporting a "two-active site" model for multiple histone H3 lysine 4 methylation.

    PubMed

    Patel, Anamika; Vought, Valarie E; Swatkoski, Stephen; Viggiano, Susan; Howard, Benny; Dharmarajan, Venkatasubramanian; Monteith, Kelsey E; Kupakuwana, Gillian; Namitz, Kevin E; Shinsky, Stephen A; Cotter, Robert J; Cosgrove, Michael S

    2014-01-10

    The mixed lineage leukemia-1 (MLL1) core complex predominantly catalyzes mono- and dimethylation of histone H3 at lysine 4 (H3K4) and is frequently altered in aggressive acute leukemias. The molecular mechanisms that account for conversion of mono- to dimethyl H3K4 (H3K4me1,2) are not well understood. In this investigation, we report that the suppressor of variegation, enhancer of zeste, trithorax (SET) domains from human MLL1 and Drosophila Trithorax undergo robust intramolecular automethylation reactions at an evolutionarily conserved cysteine residue in the active site, which is inhibited by unmodified histone H3. The location of the automethylation in the SET-I subdomain indicates that the MLL1 SET domain possesses significantly more conformational plasticity in solution than suggested by its crystal structure. We also report that MLL1 methylates Ash2L in the absence of histone H3, but only when assembled within a complex with WDR5 and RbBP5, suggesting a restraint for the architectural arrangement of subunits within the complex. Using MLL1 and Ash2L automethylation reactions as probes for histone binding, we observed that both automethylation reactions are significantly inhibited by stoichiometric amounts of unmethylated histone H3, but not by histones previously mono-, di-, or trimethylated at H3K4. These results suggest that the H3K4me1 intermediate does not significantly bind to the MLL1 SET domain during the dimethylation reaction. Consistent with this hypothesis, we demonstrate that the MLL1 core complex assembled with a catalytically inactive SET domain variant preferentially catalyzes H3K4 dimethylation using the H3K4me1 substrate. Taken together, these results are consistent with a "two-active site" model for multiple H3K4 methylation by the MLL1 core complex.

  9. Effects of complex interventions in 'skin cancer prevention and treatment': protocol for a mixed-method systematic review with qualitative comparative analysis.

    PubMed

    Beifus, Karolina; Breitbart, Eckhard; Köberlein-Neu, Juliane

    2017-09-05

    Occurring from ultraviolet radiation combined with impairing ozone levels, uncritical sun exposure and use of tanning beds an increasing number of people are affected by different types of skin cancer. But preventive interventions like skin cancer screening are still missing the evidence for effectiveness and therefore are criticised. Fundamental for an appropriate course of action is to approach the defined parameters as measures for effectiveness critically. A prerequisite should be the critical application of used parameter that are defined as measures for effectiveness. This research seeks to establish, through the available literature, the effects and conditions that prove the effectiveness of prevention strategies in skin cancer. A mixed-method approach is employed to combine quantitative to qualitative methods and answer what effects can display effectiveness considering time horizon, perspective and organisational level and what are essential and sufficient conditions to prove effectiveness and cost-effectiveness in skin cancer prevention strategies. A systematic review will be performed to spot studies from any design and assess the data quantitatively and qualitatively. Included studies from each key question will be summarised by characteristics like population, intervention, comparison, outcomes, study design, endpoints, effect estimator and so on. Beside statistical relevancies for a systematic review the qualitative method of qualitative comparative analysis (QCA) will be performed. The estimated outcomes from this review and QCA are the accomplishment and absence of effects that are appropriate for application in effectiveness assessments and further cost-effectiveness assessment. Formal ethical approval is not required as primary data will not be collected. International Prospective Register for Systematic Reviews number CRD42017053859. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights

  10. Deciphering the Temporal and Spatial Complexity in Submarine Canyons in Antarctica: the Role of Mixed Layer Depth in Regulating Primary Production

    NASA Astrophysics Data System (ADS)

    Carvalho, F.; Kohut, J. T.; Schofield, O.; Oliver, M. J.; Gorbunov, M. Y.

    2016-02-01

    There is a high spatial and temporal variability in the biophysical processes regulating primary productivity in submarine canyons in the West Antarctic Peninsula (WAP). WAP canyon heads are considered biological "hotspots" by providing predictable food resource and driving penguin foraging locations. Because the physiology and composition of the phytoplankton blooms and the physical mechanisms driving them aren't well understood, we aim to characterize the dynamics of the spring phytoplankton bloom at the head of a canyon in the WAP. A 6-year record of Slocum glider deployments is analyzed, corresponding to over 16,000 water column profiles. The mixed layer depth (MLD), determined by the maximum of the buoyancy frequency criteria, was found to be the MLD definition with the highest ecological relevance. The same holds true for other regions in Antarctica such as the Ross and Amundsen Seas. A FIRe sensor on a glider was used to evaluate physiological responses of phytoplankton to canyon dynamics using fluorescence kinetics. Initial results show a spatial influence, with increased photosynthetic efficiencies found at the canyon head. The strongest signal was the seasonal cycle. The shoaling of the MLD in early January results in increased chlorophyll a concentrations and as MLD deepens in mid season due to wind forcing, phytoplankton concentrations decrease, likely due to decreased light availability. A consistent secondary peak in chlorophyll matches a shoaling in MLD later in the growth season. A steady warming and increase in salinity of the MLD is seen throughout the season. Spatial differences were recorded at the head of the canyon and result from the local circulation. Shallower MLD found on the northern region are consistent with a fresher surface ocean (coastal influence) and increased chlorophyll concentrations. The southern region is thought to be more oceanic influenced as intrusions of warm deep water (mUCDW) to the upper water column were recorded

  11. Metal-Metal Bonding in Trinuclear, Mixed-Valence [Ti3X12](4-) (X = F, Cl, Br, I) Face-Shared Complexes.

    PubMed

    Hewage, Jinasena W; Cavigliasso, Germán; Stranger, Robert

    2015-11-16

    Metal-metal bonding in structurally characterized In4Ti3Br12, comprising linear, mixed-valence d(1)d(2)d(1) face-shared [Ti3Br12](4-) units with a Ti-Ti separation of 3.087 Å and strong antiferromagnetic coupling (Θ = -1216 K), has been investigated using density functional theory. The antiferromagnetic configuration, in which the single d electron on each terminal Ti(III) (d(1)) metal center is aligned antiparallel to the two electrons occupying the central Ti(II) (d(2)) metal site, is shown to best agree with the reported structural and magnetic data and is consistent with an S = 0 ground state in which two of the four metal-based electrons are involved in a two-electron, three-center σ bond between the Ti atoms (formal Ti-Ti bond order of ∼0.5). However, the unpaired spin densities on the Ti sites indicate that while the metal-metal σ interaction is strong, the electrons are not fully paired off and consequently dominate the ground state antiferromagnetic coupling. The same overall partially delocalized bonding regime is predicted for the other three halide [Ti3X12](4-) (X = F, Cl, I) systems with the metal-metal bonding becoming weaker as the halide group is descended. The possibility of bond-stretch isomerism was also examined where one isomer has a symmetric structure with identical Ti-Ti bonds while the other is unsymmetric with one short and one long Ti-Ti bond. Although calculations indicate that the latter form is more stable, the barrier to interconversion between equivalent unsymmetric forms, where the short Ti-Ti bond is on one side of the trinuclear unit or the other, is relatively small such that at room temperature only the averaged (symmetric) structure is likely to be observed.

  12. Resolution of parenteral nutrition-associated jaundice on changing from a soybean oil emulsion to a complex mixed-lipid emulsion.

    PubMed

    Muhammed, Rafeeq; Bremner, Ronald; Protheroe, Sue; Johnson, Tracey; Holden, Chris; Murphy, M Stephen

    2012-06-01

    Resolution of parenteral nutrition (PN)-associated jaundice has been reported in children given a reduced dose of intravenous fat using a fish oil-derived lipid emulsion. The aim of the present study was to examine the effect on PN-associated jaundice of changing from a soybean oil-derived lipid to a mixed lipid emulsion derived from soybean, coconut, olive, and fish oils without reducing the total amount of lipid given. Retrospective cohort comparison examining serum bilirubin during 6 months in children with PN-associated jaundice who changed to SMOFlipid (n=8) or remained on Intralipid (n=9). At entry, both groups received most of their energy as PN (SMOFlipid 81.5%, range 65.5-100 vs Intralipid 92.2%, range 60.3-100; P=0.37). After 6 months, both tolerated increased enteral feeding but still received large proportions of their energy as PN (SMOFlipid 68.4%, range 36.6-100 vs Intralipid 50%, range 37.6-76; P=0.15). The median bilirubin at the outset was 143 μmol/L (range 71-275) in the SMOFlipid group and 91 μmol/L (range 78-176) in the Intralipid group. After 6 months, 5 of 8 children in the SMOFlipid and 2 of 9 children in the Intralipid group had total resolution of jaundice. The median bilirubin fell by 99 μmol/L in the SMOFlipid group but increased by 79 μmol/L in the Intralipid group (P=0.02). SMOFlipid may have important protective properties for the liver and may constitute a significant advance in PN formulation. Randomised trials are needed to study the efficacy of SMOFlipid in preventing PN liver disease.

  13. Unusual Development of Iatrogenic Complex, Mixed Biliary and Duodenal Fistulas Complicating Roux-en-Y Antrectomy for Stenotic Peptic Disease of the Supraampullary Duodenum Requiring Whipple Procedure: An Uncommon Clinical Dilemma

    PubMed Central

    Polistina, Francesco A.; Costantin, Giorgio; Settin, Alessandro; Lumachi, Franco; Ambrosino, Giovanni

    2010-01-01

    Complex fistulas of the duodenum and biliary tree are severe complications of gastric surgery. The association of duodenal and major biliary fistulas occurs rarely and is a major challenge for treatment. They may occur during virtually any kind of operation, but they are more frequent in cases complicated by the presence of difficult duodenal ulcers or cancer, with a mortality rate of up to 35%. Options for treatment are many and range from simple drainage to extended resections and difficult reconstructions. Conservative treatment is the choice for well-drained fistulas, but some cases require reoperation. Very little is known about reoperation techniques and technical selection of the right patients. We present the case of a complex iatrogenic duodenal and biliary fistula. A 42-year-old Caucasian man with a diagnosis of postoperative peritonitis had been operated on 3 days earlier; an antrectomy with a Roux-en-Y reconstruction for stenotic peptic disease was performed. Conservative treatment was attempted with mixed results. Two more operations were required to achieve a definitive resolution of the fistula and related local complications. The decision was made to perform a pancreatoduodenectomy with subsequent reconstruction on a double jejunal loop. The patient did well and was discharged on postoperative day 17. In our experience pancreaticoduodenectomy may be an effective treatment of refractory and complex iatrogenic fistulas involving both the duodenum and the biliary tree. PMID:21103208

  14. Investigating vibrational relaxation in cyanide-bridged transition metal mixed-valence complexes using two-dimensional infrared and infrared pump-probe spectroscopies

    PubMed Central

    Slenkamp, Karla M.; Lynch, Michael S.; Brookes, Jennifer F.; Bannan, Caitlin C.; Daifuku, Stephanie L.; Khalil, Munira

    2016-01-01

    Using polarization-selective two-dimensional infrared (2D IR) and infrared pump-probe spectroscopies, we study vibrational relaxation of the four cyanide stretching (νCN) vibrations found in [(NH3)5RuIIINCFeII(CN)5]− (FeRu) dissolved in D2O or formamide and [(NC)5FeIICNPtIV(NH3)4NCFeII(CN)5]4− (FePtFe) dissolved in D2O. These cyanide-bridged transition metal complexes serve as models for understanding the role high frequency vibrational modes play in metal-to-metal charge transfers over a bridging ligand. However, there is currently little information about vibrational relaxation and dephasing dynamics of the anharmonically coupled νCN modes in the electronic ground state of these complexes. IR pump-probe experiments reveal that the vibrational lifetimes of the νCN modes are ∼2 times faster when FeRu is dissolved in D2O versus formamide. They also reveal that the vibrational lifetimes of the νCN modes of FePtFe in D2O are almost four times as long as for FeRu in D2O. Combined with mode-specific relaxation dynamics measured from the 2D IR experiments, the IR pump-probe experiments also reveal that intramolecular vibrational relaxation is occurring in all three systems on ∼1 ps timescale. Center line slope dynamics, which have been shown to be a measure of the frequency-frequency correlation function, reveal that the radial, axial, and trans νCN modes exhibit a ∼3 ps timescale for frequency fluctuations. This timescale is attributed to the forming and breaking of hydrogen bonds between each mode and the solvent. The results presented here along with our previous work on FeRu and FePtFe reveal a picture of coupled anharmonic νCN modes where the spectral diffusion and vibrational relaxation dynamics depend on the spatial localization of the mode on the molecular complex and its specific interaction with the solvent. PMID:27158634

  15. Biogenic inputs to ocean mixing.

    PubMed

    Katija, Kakani

    2012-03-15

    Recent studies have evoked heated debate about whether biologically generated (or biogenic) fluid disturbances affect mixing in the ocean. Estimates of